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linux/fs/btrfs/extent-tree.c
Josef Bacik 6a9fb468f1 btrfs: make caching_thread use btrfs_find_next_key 
extent-tree.c has a find_next_key that just walks up the path to find
the next key, but it is used for both the caching stuff and the snapshot
delete stuff.  The snapshot deletion stuff is special so it can't really
use btrfs_find_next_key, but the caching thread stuff can.  We just need
to fix btrfs_find_next_key to deal with ->skip_locking and then it works
exactly the same as the private find_next_key helper.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09 14:59:05 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/blkdev.h>
#include <linux/sort.h>
#include <linux/rcupdate.h>
#include <linux/kthread.h>
#include <linux/slab.h>
#include <linux/ratelimit.h>
#include <linux/percpu_counter.h>
#include <linux/lockdep.h>
#include <linux/crc32c.h>
#include "tree-log.h"
#include "disk-io.h"
#include "print-tree.h"
#include "volumes.h"
#include "raid56.h"
#include "locking.h"
#include "free-space-cache.h"
#include "free-space-tree.h"
#include "math.h"
#include "sysfs.h"
#include "qgroup.h"
#include "ref-verify.h"
#include "space-info.h"
#include "block-rsv.h"
#include "delalloc-space.h"
#include "block-group.h"
#undef SCRAMBLE_DELAYED_REFS
static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node, u64 parent,
u64 root_objectid, u64 owner_objectid,
u64 owner_offset, int refs_to_drop,
struct btrfs_delayed_extent_op *extra_op);
static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
struct extent_buffer *leaf,
struct btrfs_extent_item *ei);
static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
u64 parent, u64 root_objectid,
u64 flags, u64 owner, u64 offset,
struct btrfs_key *ins, int ref_mod);
static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op);
static int find_next_key(struct btrfs_path *path, int level,
struct btrfs_key *key);
static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
{
return (cache->flags & bits) == bits;
}
/*
* this adds the block group to the fs_info rb tree for the block group
* cache
*/
static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
struct btrfs_block_group_cache *block_group)
{
struct rb_node **p;
struct rb_node *parent = NULL;
struct btrfs_block_group_cache *cache;
spin_lock(&info->block_group_cache_lock);
p = &info->block_group_cache_tree.rb_node;
while (*p) {
parent = *p;
cache = rb_entry(parent, struct btrfs_block_group_cache,
cache_node);
if (block_group->key.objectid < cache->key.objectid) {
p = &(*p)->rb_left;
} else if (block_group->key.objectid > cache->key.objectid) {
p = &(*p)->rb_right;
} else {
spin_unlock(&info->block_group_cache_lock);
return -EEXIST;
}
}
rb_link_node(&block_group->cache_node, parent, p);
rb_insert_color(&block_group->cache_node,
&info->block_group_cache_tree);
if (info->first_logical_byte > block_group->key.objectid)
info->first_logical_byte = block_group->key.objectid;
spin_unlock(&info->block_group_cache_lock);
return 0;
}
int btrfs_add_excluded_extent(struct btrfs_fs_info *fs_info,
u64 start, u64 num_bytes)
{
u64 end = start + num_bytes - 1;
set_extent_bits(&fs_info->freed_extents[0],
start, end, EXTENT_UPTODATE);
set_extent_bits(&fs_info->freed_extents[1],
start, end, EXTENT_UPTODATE);
return 0;
}
void btrfs_free_excluded_extents(struct btrfs_block_group_cache *cache)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
u64 start, end;
start = cache->key.objectid;
end = start + cache->key.offset - 1;
clear_extent_bits(&fs_info->freed_extents[0],
start, end, EXTENT_UPTODATE);
clear_extent_bits(&fs_info->freed_extents[1],
start, end, EXTENT_UPTODATE);
}
static int exclude_super_stripes(struct btrfs_block_group_cache *cache)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
u64 bytenr;
u64 *logical;
int stripe_len;
int i, nr, ret;
if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
cache->bytes_super += stripe_len;
ret = btrfs_add_excluded_extent(fs_info, cache->key.objectid,
stripe_len);
if (ret)
return ret;
}
for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
bytenr = btrfs_sb_offset(i);
ret = btrfs_rmap_block(fs_info, cache->key.objectid,
bytenr, &logical, &nr, &stripe_len);
if (ret)
return ret;
while (nr--) {
u64 start, len;
if (logical[nr] > cache->key.objectid +
cache->key.offset)
continue;
if (logical[nr] + stripe_len <= cache->key.objectid)
continue;
start = logical[nr];
if (start < cache->key.objectid) {
start = cache->key.objectid;
len = (logical[nr] + stripe_len) - start;
} else {
len = min_t(u64, stripe_len,
cache->key.objectid +
cache->key.offset - start);
}
cache->bytes_super += len;
ret = btrfs_add_excluded_extent(fs_info, start, len);
if (ret) {
kfree(logical);
return ret;
}
}
kfree(logical);
}
return 0;
}
struct btrfs_caching_control *btrfs_get_caching_control(
struct btrfs_block_group_cache *cache)
{
struct btrfs_caching_control *ctl;
spin_lock(&cache->lock);
if (!cache->caching_ctl) {
spin_unlock(&cache->lock);
return NULL;
}
ctl = cache->caching_ctl;
refcount_inc(&ctl->count);
spin_unlock(&cache->lock);
return ctl;
}
void btrfs_put_caching_control(struct btrfs_caching_control *ctl)
{
if (refcount_dec_and_test(&ctl->count))
kfree(ctl);
}
#ifdef CONFIG_BTRFS_DEBUG
void btrfs_fragment_free_space(struct btrfs_block_group_cache *block_group)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
u64 start = block_group->key.objectid;
u64 len = block_group->key.offset;
u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
fs_info->nodesize : fs_info->sectorsize;
u64 step = chunk << 1;
while (len > chunk) {
btrfs_remove_free_space(block_group, start, chunk);
start += step;
if (len < step)
len = 0;
else
len -= step;
}
}
#endif
/*
* This is only called by btrfs_cache_block_group, since we could have freed
* extents we need to check the pinned_extents for any extents that can't be
* used yet since their free space will be released as soon as the transaction
* commits.
*/
u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
u64 start, u64 end)
{
struct btrfs_fs_info *info = block_group->fs_info;
u64 extent_start, extent_end, size, total_added = 0;
int ret;
while (start < end) {
ret = find_first_extent_bit(info->pinned_extents, start,
&extent_start, &extent_end,
EXTENT_DIRTY | EXTENT_UPTODATE,
NULL);
if (ret)
break;
if (extent_start <= start) {
start = extent_end + 1;
} else if (extent_start > start && extent_start < end) {
size = extent_start - start;
total_added += size;
ret = btrfs_add_free_space(block_group, start,
size);
BUG_ON(ret); /* -ENOMEM or logic error */
start = extent_end + 1;
} else {
break;
}
}
if (start < end) {
size = end - start;
total_added += size;
ret = btrfs_add_free_space(block_group, start, size);
BUG_ON(ret); /* -ENOMEM or logic error */
}
return total_added;
}
static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
{
struct btrfs_block_group_cache *block_group = caching_ctl->block_group;
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct btrfs_root *extent_root = fs_info->extent_root;
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_key key;
u64 total_found = 0;
u64 last = 0;
u32 nritems;
int ret;
bool wakeup = true;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
#ifdef CONFIG_BTRFS_DEBUG
/*
* If we're fragmenting we don't want to make anybody think we can
* allocate from this block group until we've had a chance to fragment
* the free space.
*/
if (btrfs_should_fragment_free_space(block_group))
wakeup = false;
#endif
/*
* We don't want to deadlock with somebody trying to allocate a new
* extent for the extent root while also trying to search the extent
* root to add free space. So we skip locking and search the commit
* root, since its read-only
*/
path->skip_locking = 1;
path->search_commit_root = 1;
path->reada = READA_FORWARD;
key.objectid = last;
key.offset = 0;
key.type = BTRFS_EXTENT_ITEM_KEY;
next:
ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
while (1) {
if (btrfs_fs_closing(fs_info) > 1) {
last = (u64)-1;
break;
}
if (path->slots[0] < nritems) {
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
} else {
ret = btrfs_find_next_key(extent_root, path, &key, 0, 0);
if (ret)
break;
if (need_resched() ||
rwsem_is_contended(&fs_info->commit_root_sem)) {
if (wakeup)
caching_ctl->progress = last;
btrfs_release_path(path);
up_read(&fs_info->commit_root_sem);
mutex_unlock(&caching_ctl->mutex);
cond_resched();
mutex_lock(&caching_ctl->mutex);
down_read(&fs_info->commit_root_sem);
goto next;
}
ret = btrfs_next_leaf(extent_root, path);
if (ret < 0)
goto out;
if (ret)
break;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
continue;
}
if (key.objectid < last) {
key.objectid = last;
key.offset = 0;
key.type = BTRFS_EXTENT_ITEM_KEY;
if (wakeup)
caching_ctl->progress = last;
btrfs_release_path(path);
goto next;
}
if (key.objectid < block_group->key.objectid) {
path->slots[0]++;
continue;
}
if (key.objectid >= block_group->key.objectid +
block_group->key.offset)
break;
if (key.type == BTRFS_EXTENT_ITEM_KEY ||
key.type == BTRFS_METADATA_ITEM_KEY) {
total_found += add_new_free_space(block_group, last,
key.objectid);
if (key.type == BTRFS_METADATA_ITEM_KEY)
last = key.objectid +
fs_info->nodesize;
else
last = key.objectid + key.offset;
if (total_found > CACHING_CTL_WAKE_UP) {
total_found = 0;
if (wakeup)
wake_up(&caching_ctl->wait);
}
}
path->slots[0]++;
}
ret = 0;
total_found += add_new_free_space(block_group, last,
block_group->key.objectid +
block_group->key.offset);
caching_ctl->progress = (u64)-1;
out:
btrfs_free_path(path);
return ret;
}
static noinline void caching_thread(struct btrfs_work *work)
{
struct btrfs_block_group_cache *block_group;
struct btrfs_fs_info *fs_info;
struct btrfs_caching_control *caching_ctl;
int ret;
caching_ctl = container_of(work, struct btrfs_caching_control, work);
block_group = caching_ctl->block_group;
fs_info = block_group->fs_info;
mutex_lock(&caching_ctl->mutex);
down_read(&fs_info->commit_root_sem);
if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
ret = load_free_space_tree(caching_ctl);
else
ret = load_extent_tree_free(caching_ctl);
spin_lock(&block_group->lock);
block_group->caching_ctl = NULL;
block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
spin_unlock(&block_group->lock);
#ifdef CONFIG_BTRFS_DEBUG
if (btrfs_should_fragment_free_space(block_group)) {
u64 bytes_used;
spin_lock(&block_group->space_info->lock);
spin_lock(&block_group->lock);
bytes_used = block_group->key.offset -
btrfs_block_group_used(&block_group->item);
block_group->space_info->bytes_used += bytes_used >> 1;
spin_unlock(&block_group->lock);
spin_unlock(&block_group->space_info->lock);
btrfs_fragment_free_space(block_group);
}
#endif
caching_ctl->progress = (u64)-1;
up_read(&fs_info->commit_root_sem);
btrfs_free_excluded_extents(block_group);
mutex_unlock(&caching_ctl->mutex);
wake_up(&caching_ctl->wait);
btrfs_put_caching_control(caching_ctl);
btrfs_put_block_group(block_group);
}
int btrfs_cache_block_group(struct btrfs_block_group_cache *cache,
int load_cache_only)
{
DEFINE_WAIT(wait);
struct btrfs_fs_info *fs_info = cache->fs_info;
struct btrfs_caching_control *caching_ctl;
int ret = 0;
caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
if (!caching_ctl)
return -ENOMEM;
INIT_LIST_HEAD(&caching_ctl->list);
mutex_init(&caching_ctl->mutex);
init_waitqueue_head(&caching_ctl->wait);
caching_ctl->block_group = cache;
caching_ctl->progress = cache->key.objectid;
refcount_set(&caching_ctl->count, 1);
btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
caching_thread, NULL, NULL);
spin_lock(&cache->lock);
/*
* This should be a rare occasion, but this could happen I think in the
* case where one thread starts to load the space cache info, and then
* some other thread starts a transaction commit which tries to do an
* allocation while the other thread is still loading the space cache
* info. The previous loop should have kept us from choosing this block
* group, but if we've moved to the state where we will wait on caching
* block groups we need to first check if we're doing a fast load here,
* so we can wait for it to finish, otherwise we could end up allocating
* from a block group who's cache gets evicted for one reason or
* another.
*/
while (cache->cached == BTRFS_CACHE_FAST) {
struct btrfs_caching_control *ctl;
ctl = cache->caching_ctl;
refcount_inc(&ctl->count);
prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
spin_unlock(&cache->lock);
schedule();
finish_wait(&ctl->wait, &wait);
btrfs_put_caching_control(ctl);
spin_lock(&cache->lock);
}
if (cache->cached != BTRFS_CACHE_NO) {
spin_unlock(&cache->lock);
kfree(caching_ctl);
return 0;
}
WARN_ON(cache->caching_ctl);
cache->caching_ctl = caching_ctl;
cache->cached = BTRFS_CACHE_FAST;
spin_unlock(&cache->lock);
if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
mutex_lock(&caching_ctl->mutex);
ret = load_free_space_cache(cache);
spin_lock(&cache->lock);
if (ret == 1) {
cache->caching_ctl = NULL;
cache->cached = BTRFS_CACHE_FINISHED;
cache->last_byte_to_unpin = (u64)-1;
caching_ctl->progress = (u64)-1;
} else {
if (load_cache_only) {
cache->caching_ctl = NULL;
cache->cached = BTRFS_CACHE_NO;
} else {
cache->cached = BTRFS_CACHE_STARTED;
cache->has_caching_ctl = 1;
}
}
spin_unlock(&cache->lock);
#ifdef CONFIG_BTRFS_DEBUG
if (ret == 1 &&
btrfs_should_fragment_free_space(cache)) {
u64 bytes_used;
spin_lock(&cache->space_info->lock);
spin_lock(&cache->lock);
bytes_used = cache->key.offset -
btrfs_block_group_used(&cache->item);
cache->space_info->bytes_used += bytes_used >> 1;
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
btrfs_fragment_free_space(cache);
}
#endif
mutex_unlock(&caching_ctl->mutex);
wake_up(&caching_ctl->wait);
if (ret == 1) {
btrfs_put_caching_control(caching_ctl);
btrfs_free_excluded_extents(cache);
return 0;
}
} else {
/*
* We're either using the free space tree or no caching at all.
* Set cached to the appropriate value and wakeup any waiters.
*/
spin_lock(&cache->lock);
if (load_cache_only) {
cache->caching_ctl = NULL;
cache->cached = BTRFS_CACHE_NO;
} else {
cache->cached = BTRFS_CACHE_STARTED;
cache->has_caching_ctl = 1;
}
spin_unlock(&cache->lock);
wake_up(&caching_ctl->wait);
}
if (load_cache_only) {
btrfs_put_caching_control(caching_ctl);
return 0;
}
down_write(&fs_info->commit_root_sem);
refcount_inc(&caching_ctl->count);
list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
up_write(&fs_info->commit_root_sem);
btrfs_get_block_group(cache);
btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
return ret;
}
static u64 generic_ref_to_space_flags(struct btrfs_ref *ref)
{
if (ref->type == BTRFS_REF_METADATA) {
if (ref->tree_ref.root == BTRFS_CHUNK_TREE_OBJECTID)
return BTRFS_BLOCK_GROUP_SYSTEM;
else
return BTRFS_BLOCK_GROUP_METADATA;
}
return BTRFS_BLOCK_GROUP_DATA;
}
static void add_pinned_bytes(struct btrfs_fs_info *fs_info,
struct btrfs_ref *ref)
{
struct btrfs_space_info *space_info;
u64 flags = generic_ref_to_space_flags(ref);
space_info = btrfs_find_space_info(fs_info, flags);
ASSERT(space_info);
percpu_counter_add_batch(&space_info->total_bytes_pinned, ref->len,
BTRFS_TOTAL_BYTES_PINNED_BATCH);
}
static void sub_pinned_bytes(struct btrfs_fs_info *fs_info,
struct btrfs_ref *ref)
{
struct btrfs_space_info *space_info;
u64 flags = generic_ref_to_space_flags(ref);
space_info = btrfs_find_space_info(fs_info, flags);
ASSERT(space_info);
percpu_counter_add_batch(&space_info->total_bytes_pinned, -ref->len,
BTRFS_TOTAL_BYTES_PINNED_BATCH);
}
/* simple helper to search for an existing data extent at a given offset */
int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
{
int ret;
struct btrfs_key key;
struct btrfs_path *path;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = start;
key.offset = len;
key.type = BTRFS_EXTENT_ITEM_KEY;
ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
btrfs_free_path(path);
return ret;
}
/*
* helper function to lookup reference count and flags of a tree block.
*
* the head node for delayed ref is used to store the sum of all the
* reference count modifications queued up in the rbtree. the head
* node may also store the extent flags to set. This way you can check
* to see what the reference count and extent flags would be if all of
* the delayed refs are not processed.
*/
int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 offset, int metadata, u64 *refs, u64 *flags)
{
struct btrfs_delayed_ref_head *head;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_path *path;
struct btrfs_extent_item *ei;
struct extent_buffer *leaf;
struct btrfs_key key;
u32 item_size;
u64 num_refs;
u64 extent_flags;
int ret;
/*
* If we don't have skinny metadata, don't bother doing anything
* different
*/
if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
offset = fs_info->nodesize;
metadata = 0;
}
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
if (!trans) {
path->skip_locking = 1;
path->search_commit_root = 1;
}
search_again:
key.objectid = bytenr;
key.offset = offset;
if (metadata)
key.type = BTRFS_METADATA_ITEM_KEY;
else
key.type = BTRFS_EXTENT_ITEM_KEY;
ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
if (ret < 0)
goto out_free;
if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
if (path->slots[0]) {
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid == bytenr &&
key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == fs_info->nodesize)
ret = 0;
}
}
if (ret == 0) {
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
if (item_size >= sizeof(*ei)) {
ei = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item);
num_refs = btrfs_extent_refs(leaf, ei);
extent_flags = btrfs_extent_flags(leaf, ei);
} else {
ret = -EINVAL;
btrfs_print_v0_err(fs_info);
if (trans)
btrfs_abort_transaction(trans, ret);
else
btrfs_handle_fs_error(fs_info, ret, NULL);
goto out_free;
}
BUG_ON(num_refs == 0);
} else {
num_refs = 0;
extent_flags = 0;
ret = 0;
}
if (!trans)
goto out;
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
if (head) {
if (!mutex_trylock(&head->mutex)) {
refcount_inc(&head->refs);
spin_unlock(&delayed_refs->lock);
btrfs_release_path(path);
/*
* Mutex was contended, block until it's released and try
* again
*/
mutex_lock(&head->mutex);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
goto search_again;
}
spin_lock(&head->lock);
if (head->extent_op && head->extent_op->update_flags)
extent_flags |= head->extent_op->flags_to_set;
else
BUG_ON(num_refs == 0);
num_refs += head->ref_mod;
spin_unlock(&head->lock);
mutex_unlock(&head->mutex);
}
spin_unlock(&delayed_refs->lock);
out:
WARN_ON(num_refs == 0);
if (refs)
*refs = num_refs;
if (flags)
*flags = extent_flags;
out_free:
btrfs_free_path(path);
return ret;
}
/*
* Back reference rules. Back refs have three main goals:
*
* 1) differentiate between all holders of references to an extent so that
* when a reference is dropped we can make sure it was a valid reference
* before freeing the extent.
*
* 2) Provide enough information to quickly find the holders of an extent
* if we notice a given block is corrupted or bad.
*
* 3) Make it easy to migrate blocks for FS shrinking or storage pool
* maintenance. This is actually the same as #2, but with a slightly
* different use case.
*
* There are two kinds of back refs. The implicit back refs is optimized
* for pointers in non-shared tree blocks. For a given pointer in a block,
* back refs of this kind provide information about the block's owner tree
* and the pointer's key. These information allow us to find the block by
* b-tree searching. The full back refs is for pointers in tree blocks not
* referenced by their owner trees. The location of tree block is recorded
* in the back refs. Actually the full back refs is generic, and can be
* used in all cases the implicit back refs is used. The major shortcoming
* of the full back refs is its overhead. Every time a tree block gets
* COWed, we have to update back refs entry for all pointers in it.
*
* For a newly allocated tree block, we use implicit back refs for
* pointers in it. This means most tree related operations only involve
* implicit back refs. For a tree block created in old transaction, the
* only way to drop a reference to it is COW it. So we can detect the
* event that tree block loses its owner tree's reference and do the
* back refs conversion.
*
* When a tree block is COWed through a tree, there are four cases:
*
* The reference count of the block is one and the tree is the block's
* owner tree. Nothing to do in this case.
*
* The reference count of the block is one and the tree is not the
* block's owner tree. In this case, full back refs is used for pointers
* in the block. Remove these full back refs, add implicit back refs for
* every pointers in the new block.
*
* The reference count of the block is greater than one and the tree is
* the block's owner tree. In this case, implicit back refs is used for
* pointers in the block. Add full back refs for every pointers in the
* block, increase lower level extents' reference counts. The original
* implicit back refs are entailed to the new block.
*
* The reference count of the block is greater than one and the tree is
* not the block's owner tree. Add implicit back refs for every pointer in
* the new block, increase lower level extents' reference count.
*
* Back Reference Key composing:
*
* The key objectid corresponds to the first byte in the extent,
* The key type is used to differentiate between types of back refs.
* There are different meanings of the key offset for different types
* of back refs.
*
* File extents can be referenced by:
*
* - multiple snapshots, subvolumes, or different generations in one subvol
* - different files inside a single subvolume
* - different offsets inside a file (bookend extents in file.c)
*
* The extent ref structure for the implicit back refs has fields for:
*
* - Objectid of the subvolume root
* - objectid of the file holding the reference
* - original offset in the file
* - how many bookend extents
*
* The key offset for the implicit back refs is hash of the first
* three fields.
*
* The extent ref structure for the full back refs has field for:
*
* - number of pointers in the tree leaf
*
* The key offset for the implicit back refs is the first byte of
* the tree leaf
*
* When a file extent is allocated, The implicit back refs is used.
* the fields are filled in:
*
* (root_key.objectid, inode objectid, offset in file, 1)
*
* When a file extent is removed file truncation, we find the
* corresponding implicit back refs and check the following fields:
*
* (btrfs_header_owner(leaf), inode objectid, offset in file)
*
* Btree extents can be referenced by:
*
* - Different subvolumes
*
* Both the implicit back refs and the full back refs for tree blocks
* only consist of key. The key offset for the implicit back refs is
* objectid of block's owner tree. The key offset for the full back refs
* is the first byte of parent block.
*
* When implicit back refs is used, information about the lowest key and
* level of the tree block are required. These information are stored in
* tree block info structure.
*/
/*
* is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
* is_data == BTRFS_REF_TYPE_DATA, data type is requiried,
* is_data == BTRFS_REF_TYPE_ANY, either type is OK.
*/
int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
struct btrfs_extent_inline_ref *iref,
enum btrfs_inline_ref_type is_data)
{
int type = btrfs_extent_inline_ref_type(eb, iref);
u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
if (type == BTRFS_TREE_BLOCK_REF_KEY ||
type == BTRFS_SHARED_BLOCK_REF_KEY ||
type == BTRFS_SHARED_DATA_REF_KEY ||
type == BTRFS_EXTENT_DATA_REF_KEY) {
if (is_data == BTRFS_REF_TYPE_BLOCK) {
if (type == BTRFS_TREE_BLOCK_REF_KEY)
return type;
if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
ASSERT(eb->fs_info);
/*
* Every shared one has parent tree
* block, which must be aligned to
* nodesize.
*/
if (offset &&
IS_ALIGNED(offset, eb->fs_info->nodesize))
return type;
}
} else if (is_data == BTRFS_REF_TYPE_DATA) {
if (type == BTRFS_EXTENT_DATA_REF_KEY)
return type;
if (type == BTRFS_SHARED_DATA_REF_KEY) {
ASSERT(eb->fs_info);
/*
* Every shared one has parent tree
* block, which must be aligned to
* nodesize.
*/
if (offset &&
IS_ALIGNED(offset, eb->fs_info->nodesize))
return type;
}
} else {
ASSERT(is_data == BTRFS_REF_TYPE_ANY);
return type;
}
}
btrfs_print_leaf((struct extent_buffer *)eb);
btrfs_err(eb->fs_info, "eb %llu invalid extent inline ref type %d",
eb->start, type);
WARN_ON(1);
return BTRFS_REF_TYPE_INVALID;
}
static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
{
u32 high_crc = ~(u32)0;
u32 low_crc = ~(u32)0;
__le64 lenum;
lenum = cpu_to_le64(root_objectid);
high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
lenum = cpu_to_le64(owner);
low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
lenum = cpu_to_le64(offset);
low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
return ((u64)high_crc << 31) ^ (u64)low_crc;
}
static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
struct btrfs_extent_data_ref *ref)
{
return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
btrfs_extent_data_ref_objectid(leaf, ref),
btrfs_extent_data_ref_offset(leaf, ref));
}
static int match_extent_data_ref(struct extent_buffer *leaf,
struct btrfs_extent_data_ref *ref,
u64 root_objectid, u64 owner, u64 offset)
{
if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
btrfs_extent_data_ref_offset(leaf, ref) != offset)
return 0;
return 1;
}
static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 parent,
u64 root_objectid,
u64 owner, u64 offset)
{
struct btrfs_root *root = trans->fs_info->extent_root;
struct btrfs_key key;
struct btrfs_extent_data_ref *ref;
struct extent_buffer *leaf;
u32 nritems;
int ret;
int recow;
int err = -ENOENT;
key.objectid = bytenr;
if (parent) {
key.type = BTRFS_SHARED_DATA_REF_KEY;
key.offset = parent;
} else {
key.type = BTRFS_EXTENT_DATA_REF_KEY;
key.offset = hash_extent_data_ref(root_objectid,
owner, offset);
}
again:
recow = 0;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0) {
err = ret;
goto fail;
}
if (parent) {
if (!ret)
return 0;
goto fail;
}
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
while (1) {
if (path->slots[0] >= nritems) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
err = ret;
if (ret)
goto fail;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
recow = 1;
}
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid != bytenr ||
key.type != BTRFS_EXTENT_DATA_REF_KEY)
goto fail;
ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
if (match_extent_data_ref(leaf, ref, root_objectid,
owner, offset)) {
if (recow) {
btrfs_release_path(path);
goto again;
}
err = 0;
break;
}
path->slots[0]++;
}
fail:
return err;
}
static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 parent,
u64 root_objectid, u64 owner,
u64 offset, int refs_to_add)
{
struct btrfs_root *root = trans->fs_info->extent_root;
struct btrfs_key key;
struct extent_buffer *leaf;
u32 size;
u32 num_refs;
int ret;
key.objectid = bytenr;
if (parent) {
key.type = BTRFS_SHARED_DATA_REF_KEY;
key.offset = parent;
size = sizeof(struct btrfs_shared_data_ref);
} else {
key.type = BTRFS_EXTENT_DATA_REF_KEY;
key.offset = hash_extent_data_ref(root_objectid,
owner, offset);
size = sizeof(struct btrfs_extent_data_ref);
}
ret = btrfs_insert_empty_item(trans, root, path, &key, size);
if (ret && ret != -EEXIST)
goto fail;
leaf = path->nodes[0];
if (parent) {
struct btrfs_shared_data_ref *ref;
ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_shared_data_ref);
if (ret == 0) {
btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
} else {
num_refs = btrfs_shared_data_ref_count(leaf, ref);
num_refs += refs_to_add;
btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
}
} else {
struct btrfs_extent_data_ref *ref;
while (ret == -EEXIST) {
ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
if (match_extent_data_ref(leaf, ref, root_objectid,
owner, offset))
break;
btrfs_release_path(path);
key.offset++;
ret = btrfs_insert_empty_item(trans, root, path, &key,
size);
if (ret && ret != -EEXIST)
goto fail;
leaf = path->nodes[0];
}
ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
if (ret == 0) {
btrfs_set_extent_data_ref_root(leaf, ref,
root_objectid);
btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
btrfs_set_extent_data_ref_offset(leaf, ref, offset);
btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
} else {
num_refs = btrfs_extent_data_ref_count(leaf, ref);
num_refs += refs_to_add;
btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
}
}
btrfs_mark_buffer_dirty(leaf);
ret = 0;
fail:
btrfs_release_path(path);
return ret;
}
static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
int refs_to_drop, int *last_ref)
{
struct btrfs_key key;
struct btrfs_extent_data_ref *ref1 = NULL;
struct btrfs_shared_data_ref *ref2 = NULL;
struct extent_buffer *leaf;
u32 num_refs = 0;
int ret = 0;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
ref1 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
num_refs = btrfs_extent_data_ref_count(leaf, ref1);
} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
ref2 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_shared_data_ref);
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
} else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
btrfs_print_v0_err(trans->fs_info);
btrfs_abort_transaction(trans, -EINVAL);
return -EINVAL;
} else {
BUG();
}
BUG_ON(num_refs < refs_to_drop);
num_refs -= refs_to_drop;
if (num_refs == 0) {
ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
*last_ref = 1;
} else {
if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
btrfs_mark_buffer_dirty(leaf);
}
return ret;
}
static noinline u32 extent_data_ref_count(struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref)
{
struct btrfs_key key;
struct extent_buffer *leaf;
struct btrfs_extent_data_ref *ref1;
struct btrfs_shared_data_ref *ref2;
u32 num_refs = 0;
int type;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
if (iref) {
/*
* If type is invalid, we should have bailed out earlier than
* this call.
*/
type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
ASSERT(type != BTRFS_REF_TYPE_INVALID);
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
num_refs = btrfs_extent_data_ref_count(leaf, ref1);
} else {
ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
}
} else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
ref1 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
num_refs = btrfs_extent_data_ref_count(leaf, ref1);
} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
ref2 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_shared_data_ref);
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
} else {
WARN_ON(1);
}
return num_refs;
}
static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 parent,
u64 root_objectid)
{
struct btrfs_root *root = trans->fs_info->extent_root;
struct btrfs_key key;
int ret;
key.objectid = bytenr;
if (parent) {
key.type = BTRFS_SHARED_BLOCK_REF_KEY;
key.offset = parent;
} else {
key.type = BTRFS_TREE_BLOCK_REF_KEY;
key.offset = root_objectid;
}
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0)
ret = -ENOENT;
return ret;
}
static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 parent,
u64 root_objectid)
{
struct btrfs_key key;
int ret;
key.objectid = bytenr;
if (parent) {
key.type = BTRFS_SHARED_BLOCK_REF_KEY;
key.offset = parent;
} else {
key.type = BTRFS_TREE_BLOCK_REF_KEY;
key.offset = root_objectid;
}
ret = btrfs_insert_empty_item(trans, trans->fs_info->extent_root,
path, &key, 0);
btrfs_release_path(path);
return ret;
}
static inline int extent_ref_type(u64 parent, u64 owner)
{
int type;
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
if (parent > 0)
type = BTRFS_SHARED_BLOCK_REF_KEY;
else
type = BTRFS_TREE_BLOCK_REF_KEY;
} else {
if (parent > 0)
type = BTRFS_SHARED_DATA_REF_KEY;
else
type = BTRFS_EXTENT_DATA_REF_KEY;
}
return type;
}
static int find_next_key(struct btrfs_path *path, int level,
struct btrfs_key *key)
{
for (; level < BTRFS_MAX_LEVEL; level++) {
if (!path->nodes[level])
break;
if (path->slots[level] + 1 >=
btrfs_header_nritems(path->nodes[level]))
continue;
if (level == 0)
btrfs_item_key_to_cpu(path->nodes[level], key,
path->slots[level] + 1);
else
btrfs_node_key_to_cpu(path->nodes[level], key,
path->slots[level] + 1);
return 0;
}
return 1;
}
/*
* look for inline back ref. if back ref is found, *ref_ret is set
* to the address of inline back ref, and 0 is returned.
*
* if back ref isn't found, *ref_ret is set to the address where it
* should be inserted, and -ENOENT is returned.
*
* if insert is true and there are too many inline back refs, the path
* points to the extent item, and -EAGAIN is returned.
*
* NOTE: inline back refs are ordered in the same way that back ref
* items in the tree are ordered.
*/
static noinline_for_stack
int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_extent_inline_ref **ref_ret,
u64 bytenr, u64 num_bytes,
u64 parent, u64 root_objectid,
u64 owner, u64 offset, int insert)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root = fs_info->extent_root;
struct btrfs_key key;
struct extent_buffer *leaf;
struct btrfs_extent_item *ei;
struct btrfs_extent_inline_ref *iref;
u64 flags;
u64 item_size;
unsigned long ptr;
unsigned long end;
int extra_size;
int type;
int want;
int ret;
int err = 0;
bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
int needed;
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
want = extent_ref_type(parent, owner);
if (insert) {
extra_size = btrfs_extent_inline_ref_size(want);
path->keep_locks = 1;
} else
extra_size = -1;
/*
* Owner is our level, so we can just add one to get the level for the
* block we are interested in.
*/
if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
key.type = BTRFS_METADATA_ITEM_KEY;
key.offset = owner;
}
again:
ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
if (ret < 0) {
err = ret;
goto out;
}
/*
* We may be a newly converted file system which still has the old fat
* extent entries for metadata, so try and see if we have one of those.
*/
if (ret > 0 && skinny_metadata) {
skinny_metadata = false;
if (path->slots[0]) {
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid == bytenr &&
key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == num_bytes)
ret = 0;
}
if (ret) {
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
btrfs_release_path(path);
goto again;
}
}
if (ret && !insert) {
err = -ENOENT;
goto out;
} else if (WARN_ON(ret)) {
err = -EIO;
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
if (unlikely(item_size < sizeof(*ei))) {
err = -EINVAL;
btrfs_print_v0_err(fs_info);
btrfs_abort_transaction(trans, err);
goto out;
}
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
flags = btrfs_extent_flags(leaf, ei);
ptr = (unsigned long)(ei + 1);
end = (unsigned long)ei + item_size;
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
ptr += sizeof(struct btrfs_tree_block_info);
BUG_ON(ptr > end);
}
if (owner >= BTRFS_FIRST_FREE_OBJECTID)
needed = BTRFS_REF_TYPE_DATA;
else
needed = BTRFS_REF_TYPE_BLOCK;
err = -ENOENT;
while (1) {
if (ptr >= end) {
WARN_ON(ptr > end);
break;
}
iref = (struct btrfs_extent_inline_ref *)ptr;
type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
if (type == BTRFS_REF_TYPE_INVALID) {
err = -EUCLEAN;
goto out;
}
if (want < type)
break;
if (want > type) {
ptr += btrfs_extent_inline_ref_size(type);
continue;
}
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
struct btrfs_extent_data_ref *dref;
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
if (match_extent_data_ref(leaf, dref, root_objectid,
owner, offset)) {
err = 0;
break;
}
if (hash_extent_data_ref_item(leaf, dref) <
hash_extent_data_ref(root_objectid, owner, offset))
break;
} else {
u64 ref_offset;
ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
if (parent > 0) {
if (parent == ref_offset) {
err = 0;
break;
}
if (ref_offset < parent)
break;
} else {
if (root_objectid == ref_offset) {
err = 0;
break;
}
if (ref_offset < root_objectid)
break;
}
}
ptr += btrfs_extent_inline_ref_size(type);
}
if (err == -ENOENT && insert) {
if (item_size + extra_size >=
BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
err = -EAGAIN;
goto out;
}
/*
* To add new inline back ref, we have to make sure
* there is no corresponding back ref item.
* For simplicity, we just do not add new inline back
* ref if there is any kind of item for this block
*/
if (find_next_key(path, 0, &key) == 0 &&
key.objectid == bytenr &&
key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
err = -EAGAIN;
goto out;
}
}
*ref_ret = (struct btrfs_extent_inline_ref *)ptr;
out:
if (insert) {
path->keep_locks = 0;
btrfs_unlock_up_safe(path, 1);
}
return err;
}
/*
* helper to add new inline back ref
*/
static noinline_for_stack
void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref,
u64 parent, u64 root_objectid,
u64 owner, u64 offset, int refs_to_add,
struct btrfs_delayed_extent_op *extent_op)
{
struct extent_buffer *leaf;
struct btrfs_extent_item *ei;
unsigned long ptr;
unsigned long end;
unsigned long item_offset;
u64 refs;
int size;
int type;
leaf = path->nodes[0];
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
item_offset = (unsigned long)iref - (unsigned long)ei;
type = extent_ref_type(parent, owner);
size = btrfs_extent_inline_ref_size(type);
btrfs_extend_item(path, size);
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
refs = btrfs_extent_refs(leaf, ei);
refs += refs_to_add;
btrfs_set_extent_refs(leaf, ei, refs);
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, ei);
ptr = (unsigned long)ei + item_offset;
end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
if (ptr < end - size)
memmove_extent_buffer(leaf, ptr + size, ptr,
end - size - ptr);
iref = (struct btrfs_extent_inline_ref *)ptr;
btrfs_set_extent_inline_ref_type(leaf, iref, type);
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
struct btrfs_extent_data_ref *dref;
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
btrfs_set_extent_data_ref_offset(leaf, dref, offset);
btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
struct btrfs_shared_data_ref *sref;
sref = (struct btrfs_shared_data_ref *)(iref + 1);
btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
} else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
} else {
btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
}
btrfs_mark_buffer_dirty(leaf);
}
static int lookup_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_extent_inline_ref **ref_ret,
u64 bytenr, u64 num_bytes, u64 parent,
u64 root_objectid, u64 owner, u64 offset)
{
int ret;
ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,
num_bytes, parent, root_objectid,
owner, offset, 0);
if (ret != -ENOENT)
return ret;
btrfs_release_path(path);
*ref_ret = NULL;
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
ret = lookup_tree_block_ref(trans, path, bytenr, parent,
root_objectid);
} else {
ret = lookup_extent_data_ref(trans, path, bytenr, parent,
root_objectid, owner, offset);
}
return ret;
}
/*
* helper to update/remove inline back ref
*/
static noinline_for_stack
void update_inline_extent_backref(struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref,
int refs_to_mod,
struct btrfs_delayed_extent_op *extent_op,
int *last_ref)
{
struct extent_buffer *leaf = path->nodes[0];
struct btrfs_extent_item *ei;
struct btrfs_extent_data_ref *dref = NULL;
struct btrfs_shared_data_ref *sref = NULL;
unsigned long ptr;
unsigned long end;
u32 item_size;
int size;
int type;
u64 refs;
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
refs = btrfs_extent_refs(leaf, ei);
WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
refs += refs_to_mod;
btrfs_set_extent_refs(leaf, ei, refs);
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, ei);
/*
* If type is invalid, we should have bailed out after
* lookup_inline_extent_backref().
*/
type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
ASSERT(type != BTRFS_REF_TYPE_INVALID);
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
refs = btrfs_extent_data_ref_count(leaf, dref);
} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
sref = (struct btrfs_shared_data_ref *)(iref + 1);
refs = btrfs_shared_data_ref_count(leaf, sref);
} else {
refs = 1;
BUG_ON(refs_to_mod != -1);
}
BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
refs += refs_to_mod;
if (refs > 0) {
if (type == BTRFS_EXTENT_DATA_REF_KEY)
btrfs_set_extent_data_ref_count(leaf, dref, refs);
else
btrfs_set_shared_data_ref_count(leaf, sref, refs);
} else {
*last_ref = 1;
size = btrfs_extent_inline_ref_size(type);
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
ptr = (unsigned long)iref;
end = (unsigned long)ei + item_size;
if (ptr + size < end)
memmove_extent_buffer(leaf, ptr, ptr + size,
end - ptr - size);
item_size -= size;
btrfs_truncate_item(path, item_size, 1);
}
btrfs_mark_buffer_dirty(leaf);
}
static noinline_for_stack
int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 num_bytes, u64 parent,
u64 root_objectid, u64 owner,
u64 offset, int refs_to_add,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_extent_inline_ref *iref;
int ret;
ret = lookup_inline_extent_backref(trans, path, &iref, bytenr,
num_bytes, parent, root_objectid,
owner, offset, 1);
if (ret == 0) {
BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
update_inline_extent_backref(path, iref, refs_to_add,
extent_op, NULL);
} else if (ret == -ENOENT) {
setup_inline_extent_backref(trans->fs_info, path, iref, parent,
root_objectid, owner, offset,
refs_to_add, extent_op);
ret = 0;
}
return ret;
}
static int insert_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 parent, u64 root_objectid,
u64 owner, u64 offset, int refs_to_add)
{
int ret;
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
BUG_ON(refs_to_add != 1);
ret = insert_tree_block_ref(trans, path, bytenr, parent,
root_objectid);
} else {
ret = insert_extent_data_ref(trans, path, bytenr, parent,
root_objectid, owner, offset,
refs_to_add);
}
return ret;
}
static int remove_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref,
int refs_to_drop, int is_data, int *last_ref)
{
int ret = 0;
BUG_ON(!is_data && refs_to_drop != 1);
if (iref) {
update_inline_extent_backref(path, iref, -refs_to_drop, NULL,
last_ref);
} else if (is_data) {
ret = remove_extent_data_ref(trans, path, refs_to_drop,
last_ref);
} else {
*last_ref = 1;
ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
}
return ret;
}
static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
u64 *discarded_bytes)
{
int j, ret = 0;
u64 bytes_left, end;
u64 aligned_start = ALIGN(start, 1 << 9);
if (WARN_ON(start != aligned_start)) {
len -= aligned_start - start;
len = round_down(len, 1 << 9);
start = aligned_start;
}
*discarded_bytes = 0;
if (!len)
return 0;
end = start + len;
bytes_left = len;
/* Skip any superblocks on this device. */
for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
u64 sb_start = btrfs_sb_offset(j);
u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
u64 size = sb_start - start;
if (!in_range(sb_start, start, bytes_left) &&
!in_range(sb_end, start, bytes_left) &&
!in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
continue;
/*
* Superblock spans beginning of range. Adjust start and
* try again.
*/
if (sb_start <= start) {
start += sb_end - start;
if (start > end) {
bytes_left = 0;
break;
}
bytes_left = end - start;
continue;
}
if (size) {
ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
GFP_NOFS, 0);
if (!ret)
*discarded_bytes += size;
else if (ret != -EOPNOTSUPP)
return ret;
}
start = sb_end;
if (start > end) {
bytes_left = 0;
break;
}
bytes_left = end - start;
}
if (bytes_left) {
ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
GFP_NOFS, 0);
if (!ret)
*discarded_bytes += bytes_left;
}
return ret;
}
int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
u64 num_bytes, u64 *actual_bytes)
{
int ret;
u64 discarded_bytes = 0;
struct btrfs_bio *bbio = NULL;
/*
* Avoid races with device replace and make sure our bbio has devices
* associated to its stripes that don't go away while we are discarding.
*/
btrfs_bio_counter_inc_blocked(fs_info);
/* Tell the block device(s) that the sectors can be discarded */
ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, bytenr, &num_bytes,
&bbio, 0);
/* Error condition is -ENOMEM */
if (!ret) {
struct btrfs_bio_stripe *stripe = bbio->stripes;
int i;
for (i = 0; i < bbio->num_stripes; i++, stripe++) {
u64 bytes;
struct request_queue *req_q;
if (!stripe->dev->bdev) {
ASSERT(btrfs_test_opt(fs_info, DEGRADED));
continue;
}
req_q = bdev_get_queue(stripe->dev->bdev);
if (!blk_queue_discard(req_q))
continue;
ret = btrfs_issue_discard(stripe->dev->bdev,
stripe->physical,
stripe->length,
&bytes);
if (!ret)
discarded_bytes += bytes;
else if (ret != -EOPNOTSUPP)
break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
/*
* Just in case we get back EOPNOTSUPP for some reason,
* just ignore the return value so we don't screw up
* people calling discard_extent.
*/
ret = 0;
}
btrfs_put_bbio(bbio);
}
btrfs_bio_counter_dec(fs_info);
if (actual_bytes)
*actual_bytes = discarded_bytes;
if (ret == -EOPNOTSUPP)
ret = 0;
return ret;
}
/* Can return -ENOMEM */
int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
struct btrfs_ref *generic_ref)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int old_ref_mod, new_ref_mod;
int ret;
ASSERT(generic_ref->type != BTRFS_REF_NOT_SET &&
generic_ref->action);
BUG_ON(generic_ref->type == BTRFS_REF_METADATA &&
generic_ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID);
if (generic_ref->type == BTRFS_REF_METADATA)
ret = btrfs_add_delayed_tree_ref(trans, generic_ref,
NULL, &old_ref_mod, &new_ref_mod);
else
ret = btrfs_add_delayed_data_ref(trans, generic_ref, 0,
&old_ref_mod, &new_ref_mod);
btrfs_ref_tree_mod(fs_info, generic_ref);
if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0)
sub_pinned_bytes(fs_info, generic_ref);
return ret;
}
/*
* __btrfs_inc_extent_ref - insert backreference for a given extent
*
* @trans: Handle of transaction
*
* @node: The delayed ref node used to get the bytenr/length for
* extent whose references are incremented.
*
* @parent: If this is a shared extent (BTRFS_SHARED_DATA_REF_KEY/
* BTRFS_SHARED_BLOCK_REF_KEY) then it holds the logical
* bytenr of the parent block. Since new extents are always
* created with indirect references, this will only be the case
* when relocating a shared extent. In that case, root_objectid
* will be BTRFS_TREE_RELOC_OBJECTID. Otheriwse, parent must
* be 0
*
* @root_objectid: The id of the root where this modification has originated,
* this can be either one of the well-known metadata trees or
* the subvolume id which references this extent.
*
* @owner: For data extents it is the inode number of the owning file.
* For metadata extents this parameter holds the level in the
* tree of the extent.
*
* @offset: For metadata extents the offset is ignored and is currently
* always passed as 0. For data extents it is the fileoffset
* this extent belongs to.
*
* @refs_to_add Number of references to add
*
* @extent_op Pointer to a structure, holding information necessary when
* updating a tree block's flags
*
*/
static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
u64 parent, u64 root_objectid,
u64 owner, u64 offset, int refs_to_add,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_extent_item *item;
struct btrfs_key key;
u64 bytenr = node->bytenr;
u64 num_bytes = node->num_bytes;
u64 refs;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = READA_FORWARD;
path->leave_spinning = 1;
/* this will setup the path even if it fails to insert the back ref */
ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
parent, root_objectid, owner,
offset, refs_to_add, extent_op);
if ((ret < 0 && ret != -EAGAIN) || !ret)
goto out;
/*
* Ok we had -EAGAIN which means we didn't have space to insert and
* inline extent ref, so just update the reference count and add a
* normal backref.
*/
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
refs = btrfs_extent_refs(leaf, item);
btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, item);
btrfs_mark_buffer_dirty(leaf);
btrfs_release_path(path);
path->reada = READA_FORWARD;
path->leave_spinning = 1;
/* now insert the actual backref */
ret = insert_extent_backref(trans, path, bytenr, parent, root_objectid,
owner, offset, refs_to_add);
if (ret)
btrfs_abort_transaction(trans, ret);
out:
btrfs_free_path(path);
return ret;
}
static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op,
int insert_reserved)
{
int ret = 0;
struct btrfs_delayed_data_ref *ref;
struct btrfs_key ins;
u64 parent = 0;
u64 ref_root = 0;
u64 flags = 0;
ins.objectid = node->bytenr;
ins.offset = node->num_bytes;
ins.type = BTRFS_EXTENT_ITEM_KEY;
ref = btrfs_delayed_node_to_data_ref(node);
trace_run_delayed_data_ref(trans->fs_info, node, ref, node->action);
if (node->type == BTRFS_SHARED_DATA_REF_KEY)
parent = ref->parent;
ref_root = ref->root;
if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
if (extent_op)
flags |= extent_op->flags_to_set;
ret = alloc_reserved_file_extent(trans, parent, ref_root,
flags, ref->objectid,
ref->offset, &ins,
node->ref_mod);
} else if (node->action == BTRFS_ADD_DELAYED_REF) {
ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
ref->objectid, ref->offset,
node->ref_mod, extent_op);
} else if (node->action == BTRFS_DROP_DELAYED_REF) {
ret = __btrfs_free_extent(trans, node, parent,
ref_root, ref->objectid,
ref->offset, node->ref_mod,
extent_op);
} else {
BUG();
}
return ret;
}
static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
struct extent_buffer *leaf,
struct btrfs_extent_item *ei)
{
u64 flags = btrfs_extent_flags(leaf, ei);
if (extent_op->update_flags) {
flags |= extent_op->flags_to_set;
btrfs_set_extent_flags(leaf, ei, flags);
}
if (extent_op->update_key) {
struct btrfs_tree_block_info *bi;
BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
bi = (struct btrfs_tree_block_info *)(ei + 1);
btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
}
}
static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_key key;
struct btrfs_path *path;
struct btrfs_extent_item *ei;
struct extent_buffer *leaf;
u32 item_size;
int ret;
int err = 0;
int metadata = !extent_op->is_data;
if (trans->aborted)
return 0;
if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
metadata = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = head->bytenr;
if (metadata) {
key.type = BTRFS_METADATA_ITEM_KEY;
key.offset = extent_op->level;
} else {
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = head->num_bytes;
}
again:
path->reada = READA_FORWARD;
path->leave_spinning = 1;
ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
if (ret < 0) {
err = ret;
goto out;
}
if (ret > 0) {
if (metadata) {
if (path->slots[0] > 0) {
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid == head->bytenr &&
key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == head->num_bytes)
ret = 0;
}
if (ret > 0) {
btrfs_release_path(path);
metadata = 0;
key.objectid = head->bytenr;
key.offset = head->num_bytes;
key.type = BTRFS_EXTENT_ITEM_KEY;
goto again;
}
} else {
err = -EIO;
goto out;
}
}
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
if (unlikely(item_size < sizeof(*ei))) {
err = -EINVAL;
btrfs_print_v0_err(fs_info);
btrfs_abort_transaction(trans, err);
goto out;
}
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
__run_delayed_extent_op(extent_op, leaf, ei);
btrfs_mark_buffer_dirty(leaf);
out:
btrfs_free_path(path);
return err;
}
static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op,
int insert_reserved)
{
int ret = 0;
struct btrfs_delayed_tree_ref *ref;
u64 parent = 0;
u64 ref_root = 0;
ref = btrfs_delayed_node_to_tree_ref(node);
trace_run_delayed_tree_ref(trans->fs_info, node, ref, node->action);
if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
parent = ref->parent;
ref_root = ref->root;
if (node->ref_mod != 1) {
btrfs_err(trans->fs_info,
"btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
node->bytenr, node->ref_mod, node->action, ref_root,
parent);
return -EIO;
}
if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
BUG_ON(!extent_op || !extent_op->update_flags);
ret = alloc_reserved_tree_block(trans, node, extent_op);
} else if (node->action == BTRFS_ADD_DELAYED_REF) {
ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
ref->level, 0, 1, extent_op);
} else if (node->action == BTRFS_DROP_DELAYED_REF) {
ret = __btrfs_free_extent(trans, node, parent, ref_root,
ref->level, 0, 1, extent_op);
} else {
BUG();
}
return ret;
}
/* helper function to actually process a single delayed ref entry */
static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op,
int insert_reserved)
{
int ret = 0;
if (trans->aborted) {
if (insert_reserved)
btrfs_pin_extent(trans->fs_info, node->bytenr,
node->num_bytes, 1);
return 0;
}
if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
node->type == BTRFS_SHARED_BLOCK_REF_KEY)
ret = run_delayed_tree_ref(trans, node, extent_op,
insert_reserved);
else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
node->type == BTRFS_SHARED_DATA_REF_KEY)
ret = run_delayed_data_ref(trans, node, extent_op,
insert_reserved);
else
BUG();
if (ret && insert_reserved)
btrfs_pin_extent(trans->fs_info, node->bytenr,
node->num_bytes, 1);
return ret;
}
static inline struct btrfs_delayed_ref_node *
select_delayed_ref(struct btrfs_delayed_ref_head *head)
{
struct btrfs_delayed_ref_node *ref;
if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
return NULL;
/*
* Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
* This is to prevent a ref count from going down to zero, which deletes
* the extent item from the extent tree, when there still are references
* to add, which would fail because they would not find the extent item.
*/
if (!list_empty(&head->ref_add_list))
return list_first_entry(&head->ref_add_list,
struct btrfs_delayed_ref_node, add_list);
ref = rb_entry(rb_first_cached(&head->ref_tree),
struct btrfs_delayed_ref_node, ref_node);
ASSERT(list_empty(&ref->add_list));
return ref;
}
static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head)
{
spin_lock(&delayed_refs->lock);
head->processing = 0;
delayed_refs->num_heads_ready++;
spin_unlock(&delayed_refs->lock);
btrfs_delayed_ref_unlock(head);
}
static struct btrfs_delayed_extent_op *cleanup_extent_op(
struct btrfs_delayed_ref_head *head)
{
struct btrfs_delayed_extent_op *extent_op = head->extent_op;
if (!extent_op)
return NULL;
if (head->must_insert_reserved) {
head->extent_op = NULL;
btrfs_free_delayed_extent_op(extent_op);
return NULL;
}
return extent_op;
}
static int run_and_cleanup_extent_op(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head)
{
struct btrfs_delayed_extent_op *extent_op;
int ret;
extent_op = cleanup_extent_op(head);
if (!extent_op)
return 0;
head->extent_op = NULL;
spin_unlock(&head->lock);
ret = run_delayed_extent_op(trans, head, extent_op);
btrfs_free_delayed_extent_op(extent_op);
return ret ? ret : 1;
}
void btrfs_cleanup_ref_head_accounting(struct btrfs_fs_info *fs_info,
struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head)
{
int nr_items = 1; /* Dropping this ref head update. */
if (head->total_ref_mod < 0) {
struct btrfs_space_info *space_info;
u64 flags;
if (head->is_data)
flags = BTRFS_BLOCK_GROUP_DATA;
else if (head->is_system)
flags = BTRFS_BLOCK_GROUP_SYSTEM;
else
flags = BTRFS_BLOCK_GROUP_METADATA;
space_info = btrfs_find_space_info(fs_info, flags);
ASSERT(space_info);
percpu_counter_add_batch(&space_info->total_bytes_pinned,
-head->num_bytes,
BTRFS_TOTAL_BYTES_PINNED_BATCH);
/*
* We had csum deletions accounted for in our delayed refs rsv,
* we need to drop the csum leaves for this update from our
* delayed_refs_rsv.
*/
if (head->is_data) {
spin_lock(&delayed_refs->lock);
delayed_refs->pending_csums -= head->num_bytes;
spin_unlock(&delayed_refs->lock);
nr_items += btrfs_csum_bytes_to_leaves(fs_info,
head->num_bytes);
}
}
btrfs_delayed_refs_rsv_release(fs_info, nr_items);
}
static int cleanup_ref_head(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_delayed_ref_root *delayed_refs;
int ret;
delayed_refs = &trans->transaction->delayed_refs;
ret = run_and_cleanup_extent_op(trans, head);
if (ret < 0) {
unselect_delayed_ref_head(delayed_refs, head);
btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
return ret;
} else if (ret) {
return ret;
}
/*
* Need to drop our head ref lock and re-acquire the delayed ref lock
* and then re-check to make sure nobody got added.
*/
spin_unlock(&head->lock);
spin_lock(&delayed_refs->lock);
spin_lock(&head->lock);
if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {
spin_unlock(&head->lock);
spin_unlock(&delayed_refs->lock);
return 1;
}
btrfs_delete_ref_head(delayed_refs, head);
spin_unlock(&head->lock);
spin_unlock(&delayed_refs->lock);
if (head->must_insert_reserved) {
btrfs_pin_extent(fs_info, head->bytenr,
head->num_bytes, 1);
if (head->is_data) {
ret = btrfs_del_csums(trans, fs_info, head->bytenr,
head->num_bytes);
}
}
btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
trace_run_delayed_ref_head(fs_info, head, 0);
btrfs_delayed_ref_unlock(head);
btrfs_put_delayed_ref_head(head);
return 0;
}
static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
struct btrfs_trans_handle *trans)
{
struct btrfs_delayed_ref_root *delayed_refs =
&trans->transaction->delayed_refs;
struct btrfs_delayed_ref_head *head = NULL;
int ret;
spin_lock(&delayed_refs->lock);
head = btrfs_select_ref_head(delayed_refs);
if (!head) {
spin_unlock(&delayed_refs->lock);
return head;
}
/*
* Grab the lock that says we are going to process all the refs for
* this head
*/
ret = btrfs_delayed_ref_lock(delayed_refs, head);
spin_unlock(&delayed_refs->lock);
/*
* We may have dropped the spin lock to get the head mutex lock, and
* that might have given someone else time to free the head. If that's
* true, it has been removed from our list and we can move on.
*/
if (ret == -EAGAIN)
head = ERR_PTR(-EAGAIN);
return head;
}
static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *locked_ref,
unsigned long *run_refs)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_delayed_extent_op *extent_op;
struct btrfs_delayed_ref_node *ref;
int must_insert_reserved = 0;
int ret;
delayed_refs = &trans->transaction->delayed_refs;
lockdep_assert_held(&locked_ref->mutex);
lockdep_assert_held(&locked_ref->lock);
while ((ref = select_delayed_ref(locked_ref))) {
if (ref->seq &&
btrfs_check_delayed_seq(fs_info, ref->seq)) {
spin_unlock(&locked_ref->lock);
unselect_delayed_ref_head(delayed_refs, locked_ref);
return -EAGAIN;
}
(*run_refs)++;
ref->in_tree = 0;
rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);
RB_CLEAR_NODE(&ref->ref_node);
if (!list_empty(&ref->add_list))
list_del(&ref->add_list);
/*
* When we play the delayed ref, also correct the ref_mod on
* head
*/
switch (ref->action) {
case BTRFS_ADD_DELAYED_REF:
case BTRFS_ADD_DELAYED_EXTENT:
locked_ref->ref_mod -= ref->ref_mod;
break;
case BTRFS_DROP_DELAYED_REF:
locked_ref->ref_mod += ref->ref_mod;
break;
default:
WARN_ON(1);
}
atomic_dec(&delayed_refs->num_entries);
/*
* Record the must_insert_reserved flag before we drop the
* spin lock.
*/
must_insert_reserved = locked_ref->must_insert_reserved;
locked_ref->must_insert_reserved = 0;
extent_op = locked_ref->extent_op;
locked_ref->extent_op = NULL;
spin_unlock(&locked_ref->lock);
ret = run_one_delayed_ref(trans, ref, extent_op,
must_insert_reserved);
btrfs_free_delayed_extent_op(extent_op);
if (ret) {
unselect_delayed_ref_head(delayed_refs, locked_ref);
btrfs_put_delayed_ref(ref);
btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
ret);
return ret;
}
btrfs_put_delayed_ref(ref);
cond_resched();
spin_lock(&locked_ref->lock);
btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
}
return 0;
}
/*
* Returns 0 on success or if called with an already aborted transaction.
* Returns -ENOMEM or -EIO on failure and will abort the transaction.
*/
static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
unsigned long nr)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_delayed_ref_head *locked_ref = NULL;
ktime_t start = ktime_get();
int ret;
unsigned long count = 0;
unsigned long actual_count = 0;
delayed_refs = &trans->transaction->delayed_refs;
do {
if (!locked_ref) {
locked_ref = btrfs_obtain_ref_head(trans);
if (IS_ERR_OR_NULL(locked_ref)) {
if (PTR_ERR(locked_ref) == -EAGAIN) {
continue;
} else {
break;
}
}
count++;
}
/*
* We need to try and merge add/drops of the same ref since we
* can run into issues with relocate dropping the implicit ref
* and then it being added back again before the drop can
* finish. If we merged anything we need to re-loop so we can
* get a good ref.
* Or we can get node references of the same type that weren't
* merged when created due to bumps in the tree mod seq, and
* we need to merge them to prevent adding an inline extent
* backref before dropping it (triggering a BUG_ON at
* insert_inline_extent_backref()).
*/
spin_lock(&locked_ref->lock);
btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
ret = btrfs_run_delayed_refs_for_head(trans, locked_ref,
&actual_count);
if (ret < 0 && ret != -EAGAIN) {
/*
* Error, btrfs_run_delayed_refs_for_head already
* unlocked everything so just bail out
*/
return ret;
} else if (!ret) {
/*
* Success, perform the usual cleanup of a processed
* head
*/
ret = cleanup_ref_head(trans, locked_ref);
if (ret > 0 ) {
/* We dropped our lock, we need to loop. */
ret = 0;
continue;
} else if (ret) {
return ret;
}
}
/*
* Either success case or btrfs_run_delayed_refs_for_head
* returned -EAGAIN, meaning we need to select another head
*/
locked_ref = NULL;
cond_resched();
} while ((nr != -1 && count < nr) || locked_ref);
/*
* We don't want to include ref heads since we can have empty ref heads
* and those will drastically skew our runtime down since we just do
* accounting, no actual extent tree updates.
*/
if (actual_count > 0) {
u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
u64 avg;
/*
* We weigh the current average higher than our current runtime
* to avoid large swings in the average.
*/
spin_lock(&delayed_refs->lock);
avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
fs_info->avg_delayed_ref_runtime = avg >> 2; /* div by 4 */
spin_unlock(&delayed_refs->lock);
}
return 0;
}
#ifdef SCRAMBLE_DELAYED_REFS
/*
* Normally delayed refs get processed in ascending bytenr order. This
* correlates in most cases to the order added. To expose dependencies on this
* order, we start to process the tree in the middle instead of the beginning
*/
static u64 find_middle(struct rb_root *root)
{
struct rb_node *n = root->rb_node;
struct btrfs_delayed_ref_node *entry;
int alt = 1;
u64 middle;
u64 first = 0, last = 0;
n = rb_first(root);
if (n) {
entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
first = entry->bytenr;
}
n = rb_last(root);
if (n) {
entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
last = entry->bytenr;
}
n = root->rb_node;
while (n) {
entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
WARN_ON(!entry->in_tree);
middle = entry->bytenr;
if (alt)
n = n->rb_left;
else
n = n->rb_right;
alt = 1 - alt;
}
return middle;
}
#endif
static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
{
u64 num_bytes;
num_bytes = heads * (sizeof(struct btrfs_extent_item) +
sizeof(struct btrfs_extent_inline_ref));
if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
num_bytes += heads * sizeof(struct btrfs_tree_block_info);
/*
* We don't ever fill up leaves all the way so multiply by 2 just to be
* closer to what we're really going to want to use.
*/
return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
}
/*
* Takes the number of bytes to be csumm'ed and figures out how many leaves it
* would require to store the csums for that many bytes.
*/
u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
{
u64 csum_size;
u64 num_csums_per_leaf;
u64 num_csums;
csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
num_csums_per_leaf = div64_u64(csum_size,
(u64)btrfs_super_csum_size(fs_info->super_copy));
num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
num_csums += num_csums_per_leaf - 1;
num_csums = div64_u64(num_csums, num_csums_per_leaf);
return num_csums;
}
/*
* this starts processing the delayed reference count updates and
* extent insertions we have queued up so far. count can be
* 0, which means to process everything in the tree at the start
* of the run (but not newly added entries), or it can be some target
* number you'd like to process.
*
* Returns 0 on success or if called with an aborted transaction
* Returns <0 on error and aborts the transaction
*/
int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
unsigned long count)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct rb_node *node;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_delayed_ref_head *head;
int ret;
int run_all = count == (unsigned long)-1;
/* We'll clean this up in btrfs_cleanup_transaction */
if (trans->aborted)
return 0;
if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
return 0;
delayed_refs = &trans->transaction->delayed_refs;
if (count == 0)
count = atomic_read(&delayed_refs->num_entries) * 2;
again:
#ifdef SCRAMBLE_DELAYED_REFS
delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
#endif
ret = __btrfs_run_delayed_refs(trans, count);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
return ret;
}
if (run_all) {
btrfs_create_pending_block_groups(trans);
spin_lock(&delayed_refs->lock);
node = rb_first_cached(&delayed_refs->href_root);
if (!node) {
spin_unlock(&delayed_refs->lock);
goto out;
}
head = rb_entry(node, struct btrfs_delayed_ref_head,
href_node);
refcount_inc(&head->refs);
spin_unlock(&delayed_refs->lock);
/* Mutex was contended, block until it's released and retry. */
mutex_lock(&head->mutex);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
cond_resched();
goto again;
}
out:
return 0;
}
int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes, u64 flags,
int level, int is_data)
{
struct btrfs_delayed_extent_op *extent_op;
int ret;
extent_op = btrfs_alloc_delayed_extent_op();
if (!extent_op)
return -ENOMEM;
extent_op->flags_to_set = flags;
extent_op->update_flags = true;
extent_op->update_key = false;
extent_op->is_data = is_data ? true : false;
extent_op->level = level;
ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
if (ret)
btrfs_free_delayed_extent_op(extent_op);
return ret;
}
static noinline int check_delayed_ref(struct btrfs_root *root,
struct btrfs_path *path,
u64 objectid, u64 offset, u64 bytenr)
{
struct btrfs_delayed_ref_head *head;
struct btrfs_delayed_ref_node *ref;
struct btrfs_delayed_data_ref *data_ref;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_transaction *cur_trans;
struct rb_node *node;
int ret = 0;
spin_lock(&root->fs_info->trans_lock);
cur_trans = root->fs_info->running_transaction;
if (cur_trans)
refcount_inc(&cur_trans->use_count);
spin_unlock(&root->fs_info->trans_lock);
if (!cur_trans)
return 0;
delayed_refs = &cur_trans->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
if (!head) {
spin_unlock(&delayed_refs->lock);
btrfs_put_transaction(cur_trans);
return 0;
}
if (!mutex_trylock(&head->mutex)) {
refcount_inc(&head->refs);
spin_unlock(&delayed_refs->lock);
btrfs_release_path(path);
/*
* Mutex was contended, block until it's released and let
* caller try again
*/
mutex_lock(&head->mutex);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
btrfs_put_transaction(cur_trans);
return -EAGAIN;
}
spin_unlock(&delayed_refs->lock);
spin_lock(&head->lock);
/*
* XXX: We should replace this with a proper search function in the
* future.
*/
for (node = rb_first_cached(&head->ref_tree); node;
node = rb_next(node)) {
ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
/* If it's a shared ref we know a cross reference exists */
if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
ret = 1;
break;
}
data_ref = btrfs_delayed_node_to_data_ref(ref);
/*
* If our ref doesn't match the one we're currently looking at
* then we have a cross reference.
*/
if (data_ref->root != root->root_key.objectid ||
data_ref->objectid != objectid ||
data_ref->offset != offset) {
ret = 1;
break;
}
}
spin_unlock(&head->lock);
mutex_unlock(&head->mutex);
btrfs_put_transaction(cur_trans);
return ret;
}
static noinline int check_committed_ref(struct btrfs_root *root,
struct btrfs_path *path,
u64 objectid, u64 offset, u64 bytenr)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *extent_root = fs_info->extent_root;
struct extent_buffer *leaf;
struct btrfs_extent_data_ref *ref;
struct btrfs_extent_inline_ref *iref;
struct btrfs_extent_item *ei;
struct btrfs_key key;
u32 item_size;
int type;
int ret;
key.objectid = bytenr;
key.offset = (u64)-1;
key.type = BTRFS_EXTENT_ITEM_KEY;
ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
BUG_ON(ret == 0); /* Corruption */
ret = -ENOENT;
if (path->slots[0] == 0)
goto out;
path->slots[0]--;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
goto out;
ret = 1;
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
if (item_size != sizeof(*ei) +
btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
goto out;
if (btrfs_extent_generation(leaf, ei) <=
btrfs_root_last_snapshot(&root->root_item))
goto out;
iref = (struct btrfs_extent_inline_ref *)(ei + 1);
type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
if (type != BTRFS_EXTENT_DATA_REF_KEY)
goto out;
ref = (struct btrfs_extent_data_ref *)(&iref->offset);
if (btrfs_extent_refs(leaf, ei) !=
btrfs_extent_data_ref_count(leaf, ref) ||
btrfs_extent_data_ref_root(leaf, ref) !=
root->root_key.objectid ||
btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
btrfs_extent_data_ref_offset(leaf, ref) != offset)
goto out;
ret = 0;
out:
return ret;
}
int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
u64 bytenr)
{
struct btrfs_path *path;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
do {
ret = check_committed_ref(root, path, objectid,
offset, bytenr);
if (ret && ret != -ENOENT)
goto out;
ret = check_delayed_ref(root, path, objectid, offset, bytenr);
} while (ret == -EAGAIN);
out:
btrfs_free_path(path);
if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
WARN_ON(ret > 0);
return ret;
}
static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
int full_backref, int inc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 bytenr;
u64 num_bytes;
u64 parent;
u64 ref_root;
u32 nritems;
struct btrfs_key key;
struct btrfs_file_extent_item *fi;
struct btrfs_ref generic_ref = { 0 };
bool for_reloc = btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC);
int i;
int action;
int level;
int ret = 0;
if (btrfs_is_testing(fs_info))
return 0;
ref_root = btrfs_header_owner(buf);
nritems = btrfs_header_nritems(buf);
level = btrfs_header_level(buf);
if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
return 0;
if (full_backref)
parent = buf->start;
else
parent = 0;
if (inc)
action = BTRFS_ADD_DELAYED_REF;
else
action = BTRFS_DROP_DELAYED_REF;
for (i = 0; i < nritems; i++) {
if (level == 0) {
btrfs_item_key_to_cpu(buf, &key, i);
if (key.type != BTRFS_EXTENT_DATA_KEY)
continue;
fi = btrfs_item_ptr(buf, i,
struct btrfs_file_extent_item);
if (btrfs_file_extent_type(buf, fi) ==
BTRFS_FILE_EXTENT_INLINE)
continue;
bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
if (bytenr == 0)
continue;
num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
key.offset -= btrfs_file_extent_offset(buf, fi);
btrfs_init_generic_ref(&generic_ref, action, bytenr,
num_bytes, parent);
generic_ref.real_root = root->root_key.objectid;
btrfs_init_data_ref(&generic_ref, ref_root, key.objectid,
key.offset);
generic_ref.skip_qgroup = for_reloc;
if (inc)
ret = btrfs_inc_extent_ref(trans, &generic_ref);
else
ret = btrfs_free_extent(trans, &generic_ref);
if (ret)
goto fail;
} else {
bytenr = btrfs_node_blockptr(buf, i);
num_bytes = fs_info->nodesize;
btrfs_init_generic_ref(&generic_ref, action, bytenr,
num_bytes, parent);
generic_ref.real_root = root->root_key.objectid;
btrfs_init_tree_ref(&generic_ref, level - 1, ref_root);
generic_ref.skip_qgroup = for_reloc;
if (inc)
ret = btrfs_inc_extent_ref(trans, &generic_ref);
else
ret = btrfs_free_extent(trans, &generic_ref);
if (ret)
goto fail;
}
}
return 0;
fail:
return ret;
}
int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct extent_buffer *buf, int full_backref)
{
return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
}
int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct extent_buffer *buf, int full_backref)
{
return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
}
static int write_one_cache_group(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_block_group_cache *cache)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
struct btrfs_root *extent_root = fs_info->extent_root;
unsigned long bi;
struct extent_buffer *leaf;
ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
if (ret) {
if (ret > 0)
ret = -ENOENT;
goto fail;
}
leaf = path->nodes[0];
bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
btrfs_mark_buffer_dirty(leaf);
fail:
btrfs_release_path(path);
return ret;
}
static int cache_save_setup(struct btrfs_block_group_cache *block_group,
struct btrfs_trans_handle *trans,
struct btrfs_path *path)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct btrfs_root *root = fs_info->tree_root;
struct inode *inode = NULL;
struct extent_changeset *data_reserved = NULL;
u64 alloc_hint = 0;
int dcs = BTRFS_DC_ERROR;
u64 num_pages = 0;
int retries = 0;
int ret = 0;
/*
* If this block group is smaller than 100 megs don't bother caching the
* block group.
*/
if (block_group->key.offset < (100 * SZ_1M)) {
spin_lock(&block_group->lock);
block_group->disk_cache_state = BTRFS_DC_WRITTEN;
spin_unlock(&block_group->lock);
return 0;
}
if (trans->aborted)
return 0;
again:
inode = lookup_free_space_inode(block_group, path);
if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
ret = PTR_ERR(inode);
btrfs_release_path(path);
goto out;
}
if (IS_ERR(inode)) {
BUG_ON(retries);
retries++;
if (block_group->ro)
goto out_free;
ret = create_free_space_inode(trans, block_group, path);
if (ret)
goto out_free;
goto again;
}
/*
* We want to set the generation to 0, that way if anything goes wrong
* from here on out we know not to trust this cache when we load up next
* time.
*/
BTRFS_I(inode)->generation = 0;
ret = btrfs_update_inode(trans, root, inode);
if (ret) {
/*
* So theoretically we could recover from this, simply set the
* super cache generation to 0 so we know to invalidate the
* cache, but then we'd have to keep track of the block groups
* that fail this way so we know we _have_ to reset this cache
* before the next commit or risk reading stale cache. So to
* limit our exposure to horrible edge cases lets just abort the
* transaction, this only happens in really bad situations
* anyway.
*/
btrfs_abort_transaction(trans, ret);
goto out_put;
}
WARN_ON(ret);
/* We've already setup this transaction, go ahead and exit */
if (block_group->cache_generation == trans->transid &&
i_size_read(inode)) {
dcs = BTRFS_DC_SETUP;
goto out_put;
}
if (i_size_read(inode) > 0) {
ret = btrfs_check_trunc_cache_free_space(fs_info,
&fs_info->global_block_rsv);
if (ret)
goto out_put;
ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
if (ret)
goto out_put;
}
spin_lock(&block_group->lock);
if (block_group->cached != BTRFS_CACHE_FINISHED ||
!btrfs_test_opt(fs_info, SPACE_CACHE)) {
/*
* don't bother trying to write stuff out _if_
* a) we're not cached,
* b) we're with nospace_cache mount option,
* c) we're with v2 space_cache (FREE_SPACE_TREE).
*/
dcs = BTRFS_DC_WRITTEN;
spin_unlock(&block_group->lock);
goto out_put;
}
spin_unlock(&block_group->lock);
/*
* We hit an ENOSPC when setting up the cache in this transaction, just
* skip doing the setup, we've already cleared the cache so we're safe.
*/
if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
ret = -ENOSPC;
goto out_put;
}
/*
* Try to preallocate enough space based on how big the block group is.
* Keep in mind this has to include any pinned space which could end up
* taking up quite a bit since it's not folded into the other space
* cache.
*/
num_pages = div_u64(block_group->key.offset, SZ_256M);
if (!num_pages)
num_pages = 1;
num_pages *= 16;
num_pages *= PAGE_SIZE;
ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
if (ret)
goto out_put;
ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
num_pages, num_pages,
&alloc_hint);
/*
* Our cache requires contiguous chunks so that we don't modify a bunch
* of metadata or split extents when writing the cache out, which means
* we can enospc if we are heavily fragmented in addition to just normal
* out of space conditions. So if we hit this just skip setting up any
* other block groups for this transaction, maybe we'll unpin enough
* space the next time around.
*/
if (!ret)
dcs = BTRFS_DC_SETUP;
else if (ret == -ENOSPC)
set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
out_put:
iput(inode);
out_free:
btrfs_release_path(path);
out:
spin_lock(&block_group->lock);
if (!ret && dcs == BTRFS_DC_SETUP)
block_group->cache_generation = trans->transid;
block_group->disk_cache_state = dcs;
spin_unlock(&block_group->lock);
extent_changeset_free(data_reserved);
return ret;
}
int btrfs_setup_space_cache(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *cache, *tmp;
struct btrfs_transaction *cur_trans = trans->transaction;
struct btrfs_path *path;
if (list_empty(&cur_trans->dirty_bgs) ||
!btrfs_test_opt(fs_info, SPACE_CACHE))
return 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
/* Could add new block groups, use _safe just in case */
list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
dirty_list) {
if (cache->disk_cache_state == BTRFS_DC_CLEAR)
cache_save_setup(cache, trans, path);
}
btrfs_free_path(path);
return 0;
}
/*
* transaction commit does final block group cache writeback during a
* critical section where nothing is allowed to change the FS. This is
* required in order for the cache to actually match the block group,
* but can introduce a lot of latency into the commit.
*
* So, btrfs_start_dirty_block_groups is here to kick off block group
* cache IO. There's a chance we'll have to redo some of it if the
* block group changes again during the commit, but it greatly reduces
* the commit latency by getting rid of the easy block groups while
* we're still allowing others to join the commit.
*/
int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *cache;
struct btrfs_transaction *cur_trans = trans->transaction;
int ret = 0;
int should_put;
struct btrfs_path *path = NULL;
LIST_HEAD(dirty);
struct list_head *io = &cur_trans->io_bgs;
int num_started = 0;
int loops = 0;
spin_lock(&cur_trans->dirty_bgs_lock);
if (list_empty(&cur_trans->dirty_bgs)) {
spin_unlock(&cur_trans->dirty_bgs_lock);
return 0;
}
list_splice_init(&cur_trans->dirty_bgs, &dirty);
spin_unlock(&cur_trans->dirty_bgs_lock);
again:
/*
* make sure all the block groups on our dirty list actually
* exist
*/
btrfs_create_pending_block_groups(trans);
if (!path) {
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
}
/*
* cache_write_mutex is here only to save us from balance or automatic
* removal of empty block groups deleting this block group while we are
* writing out the cache
*/
mutex_lock(&trans->transaction->cache_write_mutex);
while (!list_empty(&dirty)) {
bool drop_reserve = true;
cache = list_first_entry(&dirty,
struct btrfs_block_group_cache,
dirty_list);
/*
* this can happen if something re-dirties a block
* group that is already under IO. Just wait for it to
* finish and then do it all again
*/
if (!list_empty(&cache->io_list)) {
list_del_init(&cache->io_list);
btrfs_wait_cache_io(trans, cache, path);
btrfs_put_block_group(cache);
}
/*
* btrfs_wait_cache_io uses the cache->dirty_list to decide
* if it should update the cache_state. Don't delete
* until after we wait.
*
* Since we're not running in the commit critical section
* we need the dirty_bgs_lock to protect from update_block_group
*/
spin_lock(&cur_trans->dirty_bgs_lock);
list_del_init(&cache->dirty_list);
spin_unlock(&cur_trans->dirty_bgs_lock);
should_put = 1;
cache_save_setup(cache, trans, path);
if (cache->disk_cache_state == BTRFS_DC_SETUP) {
cache->io_ctl.inode = NULL;
ret = btrfs_write_out_cache(trans, cache, path);
if (ret == 0 && cache->io_ctl.inode) {
num_started++;
should_put = 0;
/*
* The cache_write_mutex is protecting the
* io_list, also refer to the definition of
* btrfs_transaction::io_bgs for more details
*/
list_add_tail(&cache->io_list, io);
} else {
/*
* if we failed to write the cache, the
* generation will be bad and life goes on
*/
ret = 0;
}
}
if (!ret) {
ret = write_one_cache_group(trans, path, cache);
/*
* Our block group might still be attached to the list
* of new block groups in the transaction handle of some
* other task (struct btrfs_trans_handle->new_bgs). This
* means its block group item isn't yet in the extent
* tree. If this happens ignore the error, as we will
* try again later in the critical section of the
* transaction commit.
*/
if (ret == -ENOENT) {
ret = 0;
spin_lock(&cur_trans->dirty_bgs_lock);
if (list_empty(&cache->dirty_list)) {
list_add_tail(&cache->dirty_list,
&cur_trans->dirty_bgs);
btrfs_get_block_group(cache);
drop_reserve = false;
}
spin_unlock(&cur_trans->dirty_bgs_lock);
} else if (ret) {
btrfs_abort_transaction(trans, ret);
}
}
/* if it's not on the io list, we need to put the block group */
if (should_put)
btrfs_put_block_group(cache);
if (drop_reserve)
btrfs_delayed_refs_rsv_release(fs_info, 1);
if (ret)
break;
/*
* Avoid blocking other tasks for too long. It might even save
* us from writing caches for block groups that are going to be
* removed.
*/
mutex_unlock(&trans->transaction->cache_write_mutex);
mutex_lock(&trans->transaction->cache_write_mutex);
}
mutex_unlock(&trans->transaction->cache_write_mutex);
/*
* go through delayed refs for all the stuff we've just kicked off
* and then loop back (just once)
*/
ret = btrfs_run_delayed_refs(trans, 0);
if (!ret && loops == 0) {
loops++;
spin_lock(&cur_trans->dirty_bgs_lock);
list_splice_init(&cur_trans->dirty_bgs, &dirty);
/*
* dirty_bgs_lock protects us from concurrent block group
* deletes too (not just cache_write_mutex).
*/
if (!list_empty(&dirty)) {
spin_unlock(&cur_trans->dirty_bgs_lock);
goto again;
}
spin_unlock(&cur_trans->dirty_bgs_lock);
} else if (ret < 0) {
btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
}
btrfs_free_path(path);
return ret;
}
int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *cache;
struct btrfs_transaction *cur_trans = trans->transaction;
int ret = 0;
int should_put;
struct btrfs_path *path;
struct list_head *io = &cur_trans->io_bgs;
int num_started = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
/*
* Even though we are in the critical section of the transaction commit,
* we can still have concurrent tasks adding elements to this
* transaction's list of dirty block groups. These tasks correspond to
* endio free space workers started when writeback finishes for a
* space cache, which run inode.c:btrfs_finish_ordered_io(), and can
* allocate new block groups as a result of COWing nodes of the root
* tree when updating the free space inode. The writeback for the space
* caches is triggered by an earlier call to
* btrfs_start_dirty_block_groups() and iterations of the following
* loop.
* Also we want to do the cache_save_setup first and then run the
* delayed refs to make sure we have the best chance at doing this all
* in one shot.
*/
spin_lock(&cur_trans->dirty_bgs_lock);
while (!list_empty(&cur_trans->dirty_bgs)) {
cache = list_first_entry(&cur_trans->dirty_bgs,
struct btrfs_block_group_cache,
dirty_list);
/*
* this can happen if cache_save_setup re-dirties a block
* group that is already under IO. Just wait for it to
* finish and then do it all again
*/
if (!list_empty(&cache->io_list)) {
spin_unlock(&cur_trans->dirty_bgs_lock);
list_del_init(&cache->io_list);
btrfs_wait_cache_io(trans, cache, path);
btrfs_put_block_group(cache);
spin_lock(&cur_trans->dirty_bgs_lock);
}
/*
* don't remove from the dirty list until after we've waited
* on any pending IO
*/
list_del_init(&cache->dirty_list);
spin_unlock(&cur_trans->dirty_bgs_lock);
should_put = 1;
cache_save_setup(cache, trans, path);
if (!ret)
ret = btrfs_run_delayed_refs(trans,
(unsigned long) -1);
if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
cache->io_ctl.inode = NULL;
ret = btrfs_write_out_cache(trans, cache, path);
if (ret == 0 && cache->io_ctl.inode) {
num_started++;
should_put = 0;
list_add_tail(&cache->io_list, io);
} else {
/*
* if we failed to write the cache, the
* generation will be bad and life goes on
*/
ret = 0;
}
}
if (!ret) {
ret = write_one_cache_group(trans, path, cache);
/*
* One of the free space endio workers might have
* created a new block group while updating a free space
* cache's inode (at inode.c:btrfs_finish_ordered_io())
* and hasn't released its transaction handle yet, in
* which case the new block group is still attached to
* its transaction handle and its creation has not
* finished yet (no block group item in the extent tree
* yet, etc). If this is the case, wait for all free
* space endio workers to finish and retry. This is a
* a very rare case so no need for a more efficient and
* complex approach.
*/
if (ret == -ENOENT) {
wait_event(cur_trans->writer_wait,
atomic_read(&cur_trans->num_writers) == 1);
ret = write_one_cache_group(trans, path, cache);
}
if (ret)
btrfs_abort_transaction(trans, ret);
}
/* if its not on the io list, we need to put the block group */
if (should_put)
btrfs_put_block_group(cache);
btrfs_delayed_refs_rsv_release(fs_info, 1);
spin_lock(&cur_trans->dirty_bgs_lock);
}
spin_unlock(&cur_trans->dirty_bgs_lock);
/*
* Refer to the definition of io_bgs member for details why it's safe
* to use it without any locking
*/
while (!list_empty(io)) {
cache = list_first_entry(io, struct btrfs_block_group_cache,
io_list);
list_del_init(&cache->io_list);
btrfs_wait_cache_io(trans, cache, path);
btrfs_put_block_group(cache);
}
btrfs_free_path(path);
return ret;
}
int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
{
struct btrfs_block_group_cache *block_group;
int readonly = 0;
block_group = btrfs_lookup_block_group(fs_info, bytenr);
if (!block_group || block_group->ro)
readonly = 1;
if (block_group)
btrfs_put_block_group(block_group);
return readonly;
}
static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 extra_flags = chunk_to_extended(flags) &
BTRFS_EXTENDED_PROFILE_MASK;
write_seqlock(&fs_info->profiles_lock);
if (flags & BTRFS_BLOCK_GROUP_DATA)
fs_info->avail_data_alloc_bits |= extra_flags;
if (flags & BTRFS_BLOCK_GROUP_METADATA)
fs_info->avail_metadata_alloc_bits |= extra_flags;
if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
fs_info->avail_system_alloc_bits |= extra_flags;
write_sequnlock(&fs_info->profiles_lock);
}
/*
* returns target flags in extended format or 0 if restripe for this
* chunk_type is not in progress
*
* should be called with balance_lock held
*/
static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
{
struct btrfs_balance_control *bctl = fs_info->balance_ctl;
u64 target = 0;
if (!bctl)
return 0;
if (flags & BTRFS_BLOCK_GROUP_DATA &&
bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
} else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
} else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
}
return target;
}
/*
* @flags: available profiles in extended format (see ctree.h)
*
* Returns reduced profile in chunk format. If profile changing is in
* progress (either running or paused) picks the target profile (if it's
* already available), otherwise falls back to plain reducing.
*/
static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 num_devices = fs_info->fs_devices->rw_devices;
u64 target;
u64 raid_type;
u64 allowed = 0;
/*
* see if restripe for this chunk_type is in progress, if so
* try to reduce to the target profile
*/
spin_lock(&fs_info->balance_lock);
target = get_restripe_target(fs_info, flags);
if (target) {
/* pick target profile only if it's already available */
if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
spin_unlock(&fs_info->balance_lock);
return extended_to_chunk(target);
}
}
spin_unlock(&fs_info->balance_lock);
/* First, mask out the RAID levels which aren't possible */
for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
if (num_devices >= btrfs_raid_array[raid_type].devs_min)
allowed |= btrfs_raid_array[raid_type].bg_flag;
}
allowed &= flags;
if (allowed & BTRFS_BLOCK_GROUP_RAID6)
allowed = BTRFS_BLOCK_GROUP_RAID6;
else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
allowed = BTRFS_BLOCK_GROUP_RAID5;
else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
allowed = BTRFS_BLOCK_GROUP_RAID10;
else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
allowed = BTRFS_BLOCK_GROUP_RAID1;
else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
allowed = BTRFS_BLOCK_GROUP_RAID0;
flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
return extended_to_chunk(flags | allowed);
}
static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
{
unsigned seq;
u64 flags;
do {
flags = orig_flags;
seq = read_seqbegin(&fs_info->profiles_lock);
if (flags & BTRFS_BLOCK_GROUP_DATA)
flags |= fs_info->avail_data_alloc_bits;
else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
flags |= fs_info->avail_system_alloc_bits;
else if (flags & BTRFS_BLOCK_GROUP_METADATA)
flags |= fs_info->avail_metadata_alloc_bits;
} while (read_seqretry(&fs_info->profiles_lock, seq));
return btrfs_reduce_alloc_profile(fs_info, flags);
}
static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 flags;
u64 ret;
if (data)
flags = BTRFS_BLOCK_GROUP_DATA;
else if (root == fs_info->chunk_root)
flags = BTRFS_BLOCK_GROUP_SYSTEM;
else
flags = BTRFS_BLOCK_GROUP_METADATA;
ret = get_alloc_profile(fs_info, flags);
return ret;
}
u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
{
return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_DATA);
}
u64 btrfs_metadata_alloc_profile(struct btrfs_fs_info *fs_info)
{
return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_METADATA);
}
u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
{
return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
}
static void force_metadata_allocation(struct btrfs_fs_info *info)
{
struct list_head *head = &info->space_info;
struct btrfs_space_info *found;
rcu_read_lock();
list_for_each_entry_rcu(found, head, list) {
if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
found->force_alloc = CHUNK_ALLOC_FORCE;
}
rcu_read_unlock();
}
static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
struct btrfs_space_info *sinfo, int force)
{
u64 bytes_used = btrfs_space_info_used(sinfo, false);
u64 thresh;
if (force == CHUNK_ALLOC_FORCE)
return 1;
/*
* in limited mode, we want to have some free space up to
* about 1% of the FS size.
*/
if (force == CHUNK_ALLOC_LIMITED) {
thresh = btrfs_super_total_bytes(fs_info->super_copy);
thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
if (sinfo->total_bytes - bytes_used < thresh)
return 1;
}
if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
return 0;
return 1;
}
static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
{
u64 num_dev;
num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max;
if (!num_dev)
num_dev = fs_info->fs_devices->rw_devices;
return num_dev;
}
/*
* If @is_allocation is true, reserve space in the system space info necessary
* for allocating a chunk, otherwise if it's false, reserve space necessary for
* removing a chunk.
*/
void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_space_info *info;
u64 left;
u64 thresh;
int ret = 0;
u64 num_devs;
/*
* Needed because we can end up allocating a system chunk and for an
* atomic and race free space reservation in the chunk block reserve.
*/
lockdep_assert_held(&fs_info->chunk_mutex);
info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
spin_lock(&info->lock);
left = info->total_bytes - btrfs_space_info_used(info, true);
spin_unlock(&info->lock);
num_devs = get_profile_num_devs(fs_info, type);
/* num_devs device items to update and 1 chunk item to add or remove */
thresh = btrfs_calc_trunc_metadata_size(fs_info, num_devs) +
btrfs_calc_trans_metadata_size(fs_info, 1);
if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
left, thresh, type);
btrfs_dump_space_info(fs_info, info, 0, 0);
}
if (left < thresh) {
u64 flags = btrfs_system_alloc_profile(fs_info);
/*
* Ignore failure to create system chunk. We might end up not
* needing it, as we might not need to COW all nodes/leafs from
* the paths we visit in the chunk tree (they were already COWed
* or created in the current transaction for example).
*/
ret = btrfs_alloc_chunk(trans, flags);
}
if (!ret) {
ret = btrfs_block_rsv_add(fs_info->chunk_root,
&fs_info->chunk_block_rsv,
thresh, BTRFS_RESERVE_NO_FLUSH);
if (!ret)
trans->chunk_bytes_reserved += thresh;
}
}
/*
* If force is CHUNK_ALLOC_FORCE:
* - return 1 if it successfully allocates a chunk,
* - return errors including -ENOSPC otherwise.
* If force is NOT CHUNK_ALLOC_FORCE:
* - return 0 if it doesn't need to allocate a new chunk,
* - return 1 if it successfully allocates a chunk,
* - return errors including -ENOSPC otherwise.
*/
int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
enum btrfs_chunk_alloc_enum force)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_space_info *space_info;
bool wait_for_alloc = false;
bool should_alloc = false;
int ret = 0;
/* Don't re-enter if we're already allocating a chunk */
if (trans->allocating_chunk)
return -ENOSPC;
space_info = btrfs_find_space_info(fs_info, flags);
ASSERT(space_info);
do {
spin_lock(&space_info->lock);
if (force < space_info->force_alloc)
force = space_info->force_alloc;
should_alloc = should_alloc_chunk(fs_info, space_info, force);
if (space_info->full) {
/* No more free physical space */
if (should_alloc)
ret = -ENOSPC;
else
ret = 0;
spin_unlock(&space_info->lock);
return ret;
} else if (!should_alloc) {
spin_unlock(&space_info->lock);
return 0;
} else if (space_info->chunk_alloc) {
/*
* Someone is already allocating, so we need to block
* until this someone is finished and then loop to
* recheck if we should continue with our allocation
* attempt.
*/
wait_for_alloc = true;
spin_unlock(&space_info->lock);
mutex_lock(&fs_info->chunk_mutex);
mutex_unlock(&fs_info->chunk_mutex);
} else {
/* Proceed with allocation */
space_info->chunk_alloc = 1;
wait_for_alloc = false;
spin_unlock(&space_info->lock);
}
cond_resched();
} while (wait_for_alloc);
mutex_lock(&fs_info->chunk_mutex);
trans->allocating_chunk = true;
/*
* If we have mixed data/metadata chunks we want to make sure we keep
* allocating mixed chunks instead of individual chunks.
*/
if (btrfs_mixed_space_info(space_info))
flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
/*
* if we're doing a data chunk, go ahead and make sure that
* we keep a reasonable number of metadata chunks allocated in the
* FS as well.
*/
if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
fs_info->data_chunk_allocations++;
if (!(fs_info->data_chunk_allocations %
fs_info->metadata_ratio))
force_metadata_allocation(fs_info);
}
/*
* Check if we have enough space in SYSTEM chunk because we may need
* to update devices.
*/
check_system_chunk(trans, flags);
ret = btrfs_alloc_chunk(trans, flags);
trans->allocating_chunk = false;
spin_lock(&space_info->lock);
if (ret < 0) {
if (ret == -ENOSPC)
space_info->full = 1;
else
goto out;
} else {
ret = 1;
space_info->max_extent_size = 0;
}
space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
out:
space_info->chunk_alloc = 0;
spin_unlock(&space_info->lock);
mutex_unlock(&fs_info->chunk_mutex);
/*
* When we allocate a new chunk we reserve space in the chunk block
* reserve to make sure we can COW nodes/leafs in the chunk tree or
* add new nodes/leafs to it if we end up needing to do it when
* inserting the chunk item and updating device items as part of the
* second phase of chunk allocation, performed by
* btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
* large number of new block groups to create in our transaction
* handle's new_bgs list to avoid exhausting the chunk block reserve
* in extreme cases - like having a single transaction create many new
* block groups when starting to write out the free space caches of all
* the block groups that were made dirty during the lifetime of the
* transaction.
*/
if (trans->chunk_bytes_reserved >= (u64)SZ_2M)
btrfs_create_pending_block_groups(trans);
return ret;
}
static int update_block_group(struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes, int alloc)
{
struct btrfs_fs_info *info = trans->fs_info;
struct btrfs_block_group_cache *cache = NULL;
u64 total = num_bytes;
u64 old_val;
u64 byte_in_group;
int factor;
int ret = 0;
/* block accounting for super block */
spin_lock(&info->delalloc_root_lock);
old_val = btrfs_super_bytes_used(info->super_copy);
if (alloc)
old_val += num_bytes;
else
old_val -= num_bytes;
btrfs_set_super_bytes_used(info->super_copy, old_val);
spin_unlock(&info->delalloc_root_lock);
while (total) {
cache = btrfs_lookup_block_group(info, bytenr);
if (!cache) {
ret = -ENOENT;
break;
}
factor = btrfs_bg_type_to_factor(cache->flags);
/*
* If this block group has free space cache written out, we
* need to make sure to load it if we are removing space. This
* is because we need the unpinning stage to actually add the
* space back to the block group, otherwise we will leak space.
*/
if (!alloc && cache->cached == BTRFS_CACHE_NO)
btrfs_cache_block_group(cache, 1);
byte_in_group = bytenr - cache->key.objectid;
WARN_ON(byte_in_group > cache->key.offset);
spin_lock(&cache->space_info->lock);
spin_lock(&cache->lock);
if (btrfs_test_opt(info, SPACE_CACHE) &&
cache->disk_cache_state < BTRFS_DC_CLEAR)
cache->disk_cache_state = BTRFS_DC_CLEAR;
old_val = btrfs_block_group_used(&cache->item);
num_bytes = min(total, cache->key.offset - byte_in_group);
if (alloc) {
old_val += num_bytes;
btrfs_set_block_group_used(&cache->item, old_val);
cache->reserved -= num_bytes;
cache->space_info->bytes_reserved -= num_bytes;
cache->space_info->bytes_used += num_bytes;
cache->space_info->disk_used += num_bytes * factor;
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
} else {
old_val -= num_bytes;
btrfs_set_block_group_used(&cache->item, old_val);
cache->pinned += num_bytes;
btrfs_space_info_update_bytes_pinned(info,
cache->space_info, num_bytes);
cache->space_info->bytes_used -= num_bytes;
cache->space_info->disk_used -= num_bytes * factor;
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
trace_btrfs_space_reservation(info, "pinned",
cache->space_info->flags,
num_bytes, 1);
percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
num_bytes,
BTRFS_TOTAL_BYTES_PINNED_BATCH);
set_extent_dirty(info->pinned_extents,
bytenr, bytenr + num_bytes - 1,
GFP_NOFS | __GFP_NOFAIL);
}
spin_lock(&trans->transaction->dirty_bgs_lock);
if (list_empty(&cache->dirty_list)) {
list_add_tail(&cache->dirty_list,
&trans->transaction->dirty_bgs);
trans->delayed_ref_updates++;
btrfs_get_block_group(cache);
}
spin_unlock(&trans->transaction->dirty_bgs_lock);
/*
* No longer have used bytes in this block group, queue it for
* deletion. We do this after adding the block group to the
* dirty list to avoid races between cleaner kthread and space
* cache writeout.
*/
if (!alloc && old_val == 0)
btrfs_mark_bg_unused(cache);
btrfs_put_block_group(cache);
total -= num_bytes;
bytenr += num_bytes;
}
/* Modified block groups are accounted for in the delayed_refs_rsv. */
btrfs_update_delayed_refs_rsv(trans);
return ret;
}
static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
{
struct btrfs_block_group_cache *cache;
u64 bytenr;
spin_lock(&fs_info->block_group_cache_lock);
bytenr = fs_info->first_logical_byte;
spin_unlock(&fs_info->block_group_cache_lock);
if (bytenr < (u64)-1)
return bytenr;
cache = btrfs_lookup_first_block_group(fs_info, search_start);
if (!cache)
return 0;
bytenr = cache->key.objectid;
btrfs_put_block_group(cache);
return bytenr;
}
static int pin_down_extent(struct btrfs_block_group_cache *cache,
u64 bytenr, u64 num_bytes, int reserved)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
spin_lock(&cache->space_info->lock);
spin_lock(&cache->lock);
cache->pinned += num_bytes;
btrfs_space_info_update_bytes_pinned(fs_info, cache->space_info,
num_bytes);
if (reserved) {
cache->reserved -= num_bytes;
cache->space_info->bytes_reserved -= num_bytes;
}
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
trace_btrfs_space_reservation(fs_info, "pinned",
cache->space_info->flags, num_bytes, 1);
percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
num_bytes, BTRFS_TOTAL_BYTES_PINNED_BATCH);
set_extent_dirty(fs_info->pinned_extents, bytenr,
bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
return 0;
}
/*
* this function must be called within transaction
*/
int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
u64 bytenr, u64 num_bytes, int reserved)
{
struct btrfs_block_group_cache *cache;
cache = btrfs_lookup_block_group(fs_info, bytenr);
BUG_ON(!cache); /* Logic error */
pin_down_extent(cache, bytenr, num_bytes, reserved);
btrfs_put_block_group(cache);
return 0;
}
/*
* this function must be called within transaction
*/
int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
u64 bytenr, u64 num_bytes)
{
struct btrfs_block_group_cache *cache;
int ret;
cache = btrfs_lookup_block_group(fs_info, bytenr);
if (!cache)
return -EINVAL;
/*
* pull in the free space cache (if any) so that our pin
* removes the free space from the cache. We have load_only set
* to one because the slow code to read in the free extents does check
* the pinned extents.
*/
btrfs_cache_block_group(cache, 1);
pin_down_extent(cache, bytenr, num_bytes, 0);
/* remove us from the free space cache (if we're there at all) */
ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
btrfs_put_block_group(cache);
return ret;
}
static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
u64 start, u64 num_bytes)
{
int ret;
struct btrfs_block_group_cache *block_group;
struct btrfs_caching_control *caching_ctl;
block_group = btrfs_lookup_block_group(fs_info, start);
if (!block_group)
return -EINVAL;
btrfs_cache_block_group(block_group, 0);
caching_ctl = btrfs_get_caching_control(block_group);
if (!caching_ctl) {
/* Logic error */
BUG_ON(!btrfs_block_group_cache_done(block_group));
ret = btrfs_remove_free_space(block_group, start, num_bytes);
} else {
mutex_lock(&caching_ctl->mutex);
if (start >= caching_ctl->progress) {
ret = btrfs_add_excluded_extent(fs_info, start,
num_bytes);
} else if (start + num_bytes <= caching_ctl->progress) {
ret = btrfs_remove_free_space(block_group,
start, num_bytes);
} else {
num_bytes = caching_ctl->progress - start;
ret = btrfs_remove_free_space(block_group,
start, num_bytes);
if (ret)
goto out_lock;
num_bytes = (start + num_bytes) -
caching_ctl->progress;
start = caching_ctl->progress;
ret = btrfs_add_excluded_extent(fs_info, start,
num_bytes);
}
out_lock:
mutex_unlock(&caching_ctl->mutex);
btrfs_put_caching_control(caching_ctl);
}
btrfs_put_block_group(block_group);
return ret;
}
int btrfs_exclude_logged_extents(struct extent_buffer *eb)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
struct btrfs_file_extent_item *item;
struct btrfs_key key;
int found_type;
int i;
int ret = 0;
if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
return 0;
for (i = 0; i < btrfs_header_nritems(eb); i++) {
btrfs_item_key_to_cpu(eb, &key, i);
if (key.type != BTRFS_EXTENT_DATA_KEY)
continue;
item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
found_type = btrfs_file_extent_type(eb, item);
if (found_type == BTRFS_FILE_EXTENT_INLINE)
continue;
if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
continue;
key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
if (ret)
break;
}
return ret;
}
static void
btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
{
atomic_inc(&bg->reservations);
}
/**
* btrfs_add_reserved_bytes - update the block_group and space info counters
* @cache: The cache we are manipulating
* @ram_bytes: The number of bytes of file content, and will be same to
* @num_bytes except for the compress path.
* @num_bytes: The number of bytes in question
* @delalloc: The blocks are allocated for the delalloc write
*
* This is called by the allocator when it reserves space. If this is a
* reservation and the block group has become read only we cannot make the
* reservation and return -EAGAIN, otherwise this function always succeeds.
*/
static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
u64 ram_bytes, u64 num_bytes, int delalloc)
{
struct btrfs_space_info *space_info = cache->space_info;
int ret = 0;
spin_lock(&space_info->lock);
spin_lock(&cache->lock);
if (cache->ro) {
ret = -EAGAIN;
} else {
cache->reserved += num_bytes;
space_info->bytes_reserved += num_bytes;
btrfs_space_info_update_bytes_may_use(cache->fs_info,
space_info, -ram_bytes);
if (delalloc)
cache->delalloc_bytes += num_bytes;
}
spin_unlock(&cache->lock);
spin_unlock(&space_info->lock);
return ret;
}
/**
* btrfs_free_reserved_bytes - update the block_group and space info counters
* @cache: The cache we are manipulating
* @num_bytes: The number of bytes in question
* @delalloc: The blocks are allocated for the delalloc write
*
* This is called by somebody who is freeing space that was never actually used
* on disk. For example if you reserve some space for a new leaf in transaction
* A and before transaction A commits you free that leaf, you call this with
* reserve set to 0 in order to clear the reservation.
*/
static void btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
u64 num_bytes, int delalloc)
{
struct btrfs_space_info *space_info = cache->space_info;
spin_lock(&space_info->lock);
spin_lock(&cache->lock);
if (cache->ro)
space_info->bytes_readonly += num_bytes;
cache->reserved -= num_bytes;
space_info->bytes_reserved -= num_bytes;
space_info->max_extent_size = 0;
if (delalloc)
cache->delalloc_bytes -= num_bytes;
spin_unlock(&cache->lock);
spin_unlock(&space_info->lock);
}
void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
{
struct btrfs_caching_control *next;
struct btrfs_caching_control *caching_ctl;
struct btrfs_block_group_cache *cache;
down_write(&fs_info->commit_root_sem);
list_for_each_entry_safe(caching_ctl, next,
&fs_info->caching_block_groups, list) {
cache = caching_ctl->block_group;
if (btrfs_block_group_cache_done(cache)) {
cache->last_byte_to_unpin = (u64)-1;
list_del_init(&caching_ctl->list);
btrfs_put_caching_control(caching_ctl);
} else {
cache->last_byte_to_unpin = caching_ctl->progress;
}
}
if (fs_info->pinned_extents == &fs_info->freed_extents[0])
fs_info->pinned_extents = &fs_info->freed_extents[1];
else
fs_info->pinned_extents = &fs_info->freed_extents[0];
up_write(&fs_info->commit_root_sem);
btrfs_update_global_block_rsv(fs_info);
}
/*
* Returns the free cluster for the given space info and sets empty_cluster to
* what it should be based on the mount options.
*/
static struct btrfs_free_cluster *
fetch_cluster_info(struct btrfs_fs_info *fs_info,
struct btrfs_space_info *space_info, u64 *empty_cluster)
{
struct btrfs_free_cluster *ret = NULL;
*empty_cluster = 0;
if (btrfs_mixed_space_info(space_info))
return ret;
if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
ret = &fs_info->meta_alloc_cluster;
if (btrfs_test_opt(fs_info, SSD))
*empty_cluster = SZ_2M;
else
*empty_cluster = SZ_64K;
} else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
btrfs_test_opt(fs_info, SSD_SPREAD)) {
*empty_cluster = SZ_2M;
ret = &fs_info->data_alloc_cluster;
}
return ret;
}
static int unpin_extent_range(struct btrfs_fs_info *fs_info,
u64 start, u64 end,
const bool return_free_space)
{
struct btrfs_block_group_cache *cache = NULL;
struct btrfs_space_info *space_info;
struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
struct btrfs_free_cluster *cluster = NULL;
u64 len;
u64 total_unpinned = 0;
u64 empty_cluster = 0;
bool readonly;
while (start <= end) {
readonly = false;
if (!cache ||
start >= cache->key.objectid + cache->key.offset) {
if (cache)
btrfs_put_block_group(cache);
total_unpinned = 0;
cache = btrfs_lookup_block_group(fs_info, start);
BUG_ON(!cache); /* Logic error */
cluster = fetch_cluster_info(fs_info,
cache->space_info,
&empty_cluster);
empty_cluster <<= 1;
}
len = cache->key.objectid + cache->key.offset - start;
len = min(len, end + 1 - start);
if (start < cache->last_byte_to_unpin) {
len = min(len, cache->last_byte_to_unpin - start);
if (return_free_space)
btrfs_add_free_space(cache, start, len);
}
start += len;
total_unpinned += len;
space_info = cache->space_info;
/*
* If this space cluster has been marked as fragmented and we've
* unpinned enough in this block group to potentially allow a
* cluster to be created inside of it go ahead and clear the
* fragmented check.
*/
if (cluster && cluster->fragmented &&
total_unpinned > empty_cluster) {
spin_lock(&cluster->lock);
cluster->fragmented = 0;
spin_unlock(&cluster->lock);
}
spin_lock(&space_info->lock);
spin_lock(&cache->lock);
cache->pinned -= len;
btrfs_space_info_update_bytes_pinned(fs_info, space_info, -len);
trace_btrfs_space_reservation(fs_info, "pinned",
space_info->flags, len, 0);
space_info->max_extent_size = 0;
percpu_counter_add_batch(&space_info->total_bytes_pinned,
-len, BTRFS_TOTAL_BYTES_PINNED_BATCH);
if (cache->ro) {
space_info->bytes_readonly += len;
readonly = true;
}
spin_unlock(&cache->lock);
if (!readonly && return_free_space &&
global_rsv->space_info == space_info) {
u64 to_add = len;
spin_lock(&global_rsv->lock);
if (!global_rsv->full) {
to_add = min(len, global_rsv->size -
global_rsv->reserved);
global_rsv->reserved += to_add;
btrfs_space_info_update_bytes_may_use(fs_info,
space_info, to_add);
if (global_rsv->reserved >= global_rsv->size)
global_rsv->full = 1;
trace_btrfs_space_reservation(fs_info,
"space_info",
space_info->flags,
to_add, 1);
len -= to_add;
}
spin_unlock(&global_rsv->lock);
/* Add to any tickets we may have */
if (len)
btrfs_space_info_add_new_bytes(fs_info,
space_info, len);
}
spin_unlock(&space_info->lock);
}
if (cache)
btrfs_put_block_group(cache);
return 0;
}
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *block_group, *tmp;
struct list_head *deleted_bgs;
struct extent_io_tree *unpin;
u64 start;
u64 end;
int ret;
if (fs_info->pinned_extents == &fs_info->freed_extents[0])
unpin = &fs_info->freed_extents[1];
else
unpin = &fs_info->freed_extents[0];
while (!trans->aborted) {
struct extent_state *cached_state = NULL;
mutex_lock(&fs_info->unused_bg_unpin_mutex);
ret = find_first_extent_bit(unpin, 0, &start, &end,
EXTENT_DIRTY, &cached_state);
if (ret) {
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
break;
}
if (btrfs_test_opt(fs_info, DISCARD))
ret = btrfs_discard_extent(fs_info, start,
end + 1 - start, NULL);
clear_extent_dirty(unpin, start, end, &cached_state);
unpin_extent_range(fs_info, start, end, true);
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
free_extent_state(cached_state);
cond_resched();
}
/*
* Transaction is finished. We don't need the lock anymore. We
* do need to clean up the block groups in case of a transaction
* abort.
*/
deleted_bgs = &trans->transaction->deleted_bgs;
list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
u64 trimmed = 0;
ret = -EROFS;
if (!trans->aborted)
ret = btrfs_discard_extent(fs_info,
block_group->key.objectid,
block_group->key.offset,
&trimmed);
list_del_init(&block_group->bg_list);
btrfs_put_block_group_trimming(block_group);
btrfs_put_block_group(block_group);
if (ret) {
const char *errstr = btrfs_decode_error(ret);
btrfs_warn(fs_info,
"discard failed while removing blockgroup: errno=%d %s",
ret, errstr);
}
}
return 0;
}
static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node, u64 parent,
u64 root_objectid, u64 owner_objectid,
u64 owner_offset, int refs_to_drop,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_fs_info *info = trans->fs_info;
struct btrfs_key key;
struct btrfs_path *path;
struct btrfs_root *extent_root = info->extent_root;
struct extent_buffer *leaf;
struct btrfs_extent_item *ei;
struct btrfs_extent_inline_ref *iref;
int ret;
int is_data;
int extent_slot = 0;
int found_extent = 0;
int num_to_del = 1;
u32 item_size;
u64 refs;
u64 bytenr = node->bytenr;
u64 num_bytes = node->num_bytes;
int last_ref = 0;
bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = READA_FORWARD;
path->leave_spinning = 1;
is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
BUG_ON(!is_data && refs_to_drop != 1);
if (is_data)
skinny_metadata = false;
ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,
parent, root_objectid, owner_objectid,
owner_offset);
if (ret == 0) {
extent_slot = path->slots[0];
while (extent_slot >= 0) {
btrfs_item_key_to_cpu(path->nodes[0], &key,
extent_slot);
if (key.objectid != bytenr)
break;
if (key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == num_bytes) {
found_extent = 1;
break;
}
if (key.type == BTRFS_METADATA_ITEM_KEY &&
key.offset == owner_objectid) {
found_extent = 1;
break;
}
if (path->slots[0] - extent_slot > 5)
break;
extent_slot--;
}
if (!found_extent) {
BUG_ON(iref);
ret = remove_extent_backref(trans, path, NULL,
refs_to_drop,
is_data, &last_ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
btrfs_release_path(path);
path->leave_spinning = 1;
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
if (!is_data && skinny_metadata) {
key.type = BTRFS_METADATA_ITEM_KEY;
key.offset = owner_objectid;
}
ret = btrfs_search_slot(trans, extent_root,
&key, path, -1, 1);
if (ret > 0 && skinny_metadata && path->slots[0]) {
/*
* Couldn't find our skinny metadata item,
* see if we have ye olde extent item.
*/
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid == bytenr &&
key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == num_bytes)
ret = 0;
}
if (ret > 0 && skinny_metadata) {
skinny_metadata = false;
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
btrfs_release_path(path);
ret = btrfs_search_slot(trans, extent_root,
&key, path, -1, 1);
}
if (ret) {
btrfs_err(info,
"umm, got %d back from search, was looking for %llu",
ret, bytenr);
if (ret > 0)
btrfs_print_leaf(path->nodes[0]);
}
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}
extent_slot = path->slots[0];
}
} else if (WARN_ON(ret == -ENOENT)) {
btrfs_print_leaf(path->nodes[0]);
btrfs_err(info,
"unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu",
bytenr, parent, root_objectid, owner_objectid,
owner_offset);
btrfs_abort_transaction(trans, ret);
goto out;
} else {
btrfs_abort_transaction(trans, ret);
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, extent_slot);
if (unlikely(item_size < sizeof(*ei))) {
ret = -EINVAL;
btrfs_print_v0_err(info);
btrfs_abort_transaction(trans, ret);
goto out;
}
ei = btrfs_item_ptr(leaf, extent_slot,
struct btrfs_extent_item);
if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
key.type == BTRFS_EXTENT_ITEM_KEY) {
struct btrfs_tree_block_info *bi;
BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
bi = (struct btrfs_tree_block_info *)(ei + 1);
WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
}
refs = btrfs_extent_refs(leaf, ei);
if (refs < refs_to_drop) {
btrfs_err(info,
"trying to drop %d refs but we only have %Lu for bytenr %Lu",
refs_to_drop, refs, bytenr);
ret = -EINVAL;
btrfs_abort_transaction(trans, ret);
goto out;
}
refs -= refs_to_drop;
if (refs > 0) {
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, ei);
/*
* In the case of inline back ref, reference count will
* be updated by remove_extent_backref
*/
if (iref) {
BUG_ON(!found_extent);
} else {
btrfs_set_extent_refs(leaf, ei, refs);
btrfs_mark_buffer_dirty(leaf);
}
if (found_extent) {
ret = remove_extent_backref(trans, path, iref,
refs_to_drop, is_data,
&last_ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
} else {
if (found_extent) {
BUG_ON(is_data && refs_to_drop !=
extent_data_ref_count(path, iref));
if (iref) {
BUG_ON(path->slots[0] != extent_slot);
} else {
BUG_ON(path->slots[0] != extent_slot + 1);
path->slots[0] = extent_slot;
num_to_del = 2;
}
}
last_ref = 1;
ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
num_to_del);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
btrfs_release_path(path);
if (is_data) {
ret = btrfs_del_csums(trans, info, bytenr, num_bytes);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
ret = add_to_free_space_tree(trans, bytenr, num_bytes);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
ret = update_block_group(trans, bytenr, num_bytes, 0);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
btrfs_release_path(path);
out:
btrfs_free_path(path);
return ret;
}
/*
* when we free an block, it is possible (and likely) that we free the last
* delayed ref for that extent as well. This searches the delayed ref tree for
* a given extent, and if there are no other delayed refs to be processed, it
* removes it from the tree.
*/
static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
u64 bytenr)
{
struct btrfs_delayed_ref_head *head;
struct btrfs_delayed_ref_root *delayed_refs;
int ret = 0;
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
if (!head)
goto out_delayed_unlock;
spin_lock(&head->lock);
if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
goto out;
if (cleanup_extent_op(head) != NULL)
goto out;
/*
* waiting for the lock here would deadlock. If someone else has it
* locked they are already in the process of dropping it anyway
*/
if (!mutex_trylock(&head->mutex))
goto out;
btrfs_delete_ref_head(delayed_refs, head);
head->processing = 0;
spin_unlock(&head->lock);
spin_unlock(&delayed_refs->lock);
BUG_ON(head->extent_op);
if (head->must_insert_reserved)
ret = 1;
btrfs_cleanup_ref_head_accounting(trans->fs_info, delayed_refs, head);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
return ret;
out:
spin_unlock(&head->lock);
out_delayed_unlock:
spin_unlock(&delayed_refs->lock);
return 0;
}
void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
u64 parent, int last_ref)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_ref generic_ref = { 0 };
int pin = 1;
int ret;
btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF,
buf->start, buf->len, parent);
btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf),
root->root_key.objectid);
if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
int old_ref_mod, new_ref_mod;
btrfs_ref_tree_mod(fs_info, &generic_ref);
ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL,
&old_ref_mod, &new_ref_mod);
BUG_ON(ret); /* -ENOMEM */
pin = old_ref_mod >= 0 && new_ref_mod < 0;
}
if (last_ref && btrfs_header_generation(buf) == trans->transid) {
struct btrfs_block_group_cache *cache;
if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
ret = check_ref_cleanup(trans, buf->start);
if (!ret)
goto out;
}
pin = 0;
cache = btrfs_lookup_block_group(fs_info, buf->start);
if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
pin_down_extent(cache, buf->start, buf->len, 1);
btrfs_put_block_group(cache);
goto out;
}
WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
btrfs_add_free_space(cache, buf->start, buf->len);
btrfs_free_reserved_bytes(cache, buf->len, 0);
btrfs_put_block_group(cache);
trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
}
out:
if (pin)
add_pinned_bytes(fs_info, &generic_ref);
if (last_ref) {
/*
* Deleting the buffer, clear the corrupt flag since it doesn't
* matter anymore.
*/
clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
}
}
/* Can return -ENOMEM */
int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int old_ref_mod, new_ref_mod;
int ret;
if (btrfs_is_testing(fs_info))
return 0;
/*
* tree log blocks never actually go into the extent allocation
* tree, just update pinning info and exit early.
*/
if ((ref->type == BTRFS_REF_METADATA &&
ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID) ||
(ref->type == BTRFS_REF_DATA &&
ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)) {
/* unlocks the pinned mutex */
btrfs_pin_extent(fs_info, ref->bytenr, ref->len, 1);
old_ref_mod = new_ref_mod = 0;
ret = 0;
} else if (ref->type == BTRFS_REF_METADATA) {
ret = btrfs_add_delayed_tree_ref(trans, ref, NULL,
&old_ref_mod, &new_ref_mod);
} else {
ret = btrfs_add_delayed_data_ref(trans, ref, 0,
&old_ref_mod, &new_ref_mod);
}
if (!((ref->type == BTRFS_REF_METADATA &&
ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID) ||
(ref->type == BTRFS_REF_DATA &&
ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)))
btrfs_ref_tree_mod(fs_info, ref);
if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0)
add_pinned_bytes(fs_info, ref);
return ret;
}
/*
* when we wait for progress in the block group caching, its because
* our allocation attempt failed at least once. So, we must sleep
* and let some progress happen before we try again.
*
* This function will sleep at least once waiting for new free space to
* show up, and then it will check the block group free space numbers
* for our min num_bytes. Another option is to have it go ahead
* and look in the rbtree for a free extent of a given size, but this
* is a good start.
*
* Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
* any of the information in this block group.
*/
void btrfs_wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
u64 num_bytes)
{
struct btrfs_caching_control *caching_ctl;
caching_ctl = btrfs_get_caching_control(cache);
if (!caching_ctl)
return;
wait_event(caching_ctl->wait, btrfs_block_group_cache_done(cache) ||
(cache->free_space_ctl->free_space >= num_bytes));
btrfs_put_caching_control(caching_ctl);
}
int btrfs_wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
{
struct btrfs_caching_control *caching_ctl;
int ret = 0;
caching_ctl = btrfs_get_caching_control(cache);
if (!caching_ctl)
return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
wait_event(caching_ctl->wait, btrfs_block_group_cache_done(cache));
if (cache->cached == BTRFS_CACHE_ERROR)
ret = -EIO;
btrfs_put_caching_control(caching_ctl);
return ret;
}
enum btrfs_loop_type {
LOOP_CACHING_NOWAIT,
LOOP_CACHING_WAIT,
LOOP_ALLOC_CHUNK,
LOOP_NO_EMPTY_SIZE,
};
static inline void
btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
int delalloc)
{
if (delalloc)
down_read(&cache->data_rwsem);
}
static inline void
btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
int delalloc)
{
btrfs_get_block_group(cache);
if (delalloc)
down_read(&cache->data_rwsem);
}
static struct btrfs_block_group_cache *
btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
struct btrfs_free_cluster *cluster,
int delalloc)
{
struct btrfs_block_group_cache *used_bg = NULL;
spin_lock(&cluster->refill_lock);
while (1) {
used_bg = cluster->block_group;
if (!used_bg)
return NULL;
if (used_bg == block_group)
return used_bg;
btrfs_get_block_group(used_bg);
if (!delalloc)
return used_bg;
if (down_read_trylock(&used_bg->data_rwsem))
return used_bg;
spin_unlock(&cluster->refill_lock);
/* We should only have one-level nested. */
down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
spin_lock(&cluster->refill_lock);
if (used_bg == cluster->block_group)
return used_bg;
up_read(&used_bg->data_rwsem);
btrfs_put_block_group(used_bg);
}
}
static inline void
btrfs_release_block_group(struct btrfs_block_group_cache *cache,
int delalloc)
{
if (delalloc)
up_read(&cache->data_rwsem);
btrfs_put_block_group(cache);
}
/*
* Structure used internally for find_free_extent() function. Wraps needed
* parameters.
*/
struct find_free_extent_ctl {
/* Basic allocation info */
u64 ram_bytes;
u64 num_bytes;
u64 empty_size;
u64 flags;
int delalloc;
/* Where to start the search inside the bg */
u64 search_start;
/* For clustered allocation */
u64 empty_cluster;
bool have_caching_bg;
bool orig_have_caching_bg;
/* RAID index, converted from flags */
int index;
/*
* Current loop number, check find_free_extent_update_loop() for details
*/
int loop;
/*
* Whether we're refilling a cluster, if true we need to re-search
* current block group but don't try to refill the cluster again.
*/
bool retry_clustered;
/*
* Whether we're updating free space cache, if true we need to re-search
* current block group but don't try updating free space cache again.
*/
bool retry_unclustered;
/* If current block group is cached */
int cached;
/* Max contiguous hole found */
u64 max_extent_size;
/* Total free space from free space cache, not always contiguous */
u64 total_free_space;
/* Found result */
u64 found_offset;
};
/*
* Helper function for find_free_extent().
*
* Return -ENOENT to inform caller that we need fallback to unclustered mode.
* Return -EAGAIN to inform caller that we need to re-search this block group
* Return >0 to inform caller that we find nothing
* Return 0 means we have found a location and set ffe_ctl->found_offset.
*/
static int find_free_extent_clustered(struct btrfs_block_group_cache *bg,
struct btrfs_free_cluster *last_ptr,
struct find_free_extent_ctl *ffe_ctl,
struct btrfs_block_group_cache **cluster_bg_ret)
{
struct btrfs_block_group_cache *cluster_bg;
u64 aligned_cluster;
u64 offset;
int ret;
cluster_bg = btrfs_lock_cluster(bg, last_ptr, ffe_ctl->delalloc);
if (!cluster_bg)
goto refill_cluster;
if (cluster_bg != bg && (cluster_bg->ro ||
!block_group_bits(cluster_bg, ffe_ctl->flags)))
goto release_cluster;
offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr,
ffe_ctl->num_bytes, cluster_bg->key.objectid,
&ffe_ctl->max_extent_size);
if (offset) {
/* We have a block, we're done */
spin_unlock(&last_ptr->refill_lock);
trace_btrfs_reserve_extent_cluster(cluster_bg,
ffe_ctl->search_start, ffe_ctl->num_bytes);
*cluster_bg_ret = cluster_bg;
ffe_ctl->found_offset = offset;
return 0;
}
WARN_ON(last_ptr->block_group != cluster_bg);
release_cluster:
/*
* If we are on LOOP_NO_EMPTY_SIZE, we can't set up a new clusters, so
* lets just skip it and let the allocator find whatever block it can
* find. If we reach this point, we will have tried the cluster
* allocator plenty of times and not have found anything, so we are
* likely way too fragmented for the clustering stuff to find anything.
*
* However, if the cluster is taken from the current block group,
* release the cluster first, so that we stand a better chance of
* succeeding in the unclustered allocation.
*/
if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE && cluster_bg != bg) {
spin_unlock(&last_ptr->refill_lock);
btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
return -ENOENT;
}
/* This cluster didn't work out, free it and start over */
btrfs_return_cluster_to_free_space(NULL, last_ptr);
if (cluster_bg != bg)
btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
refill_cluster:
if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE) {
spin_unlock(&last_ptr->refill_lock);
return -ENOENT;
}
aligned_cluster = max_t(u64,
ffe_ctl->empty_cluster + ffe_ctl->empty_size,
bg->full_stripe_len);
ret = btrfs_find_space_cluster(bg, last_ptr, ffe_ctl->search_start,
ffe_ctl->num_bytes, aligned_cluster);
if (ret == 0) {
/* Now pull our allocation out of this cluster */
offset = btrfs_alloc_from_cluster(bg, last_ptr,
ffe_ctl->num_bytes, ffe_ctl->search_start,
&ffe_ctl->max_extent_size);
if (offset) {
/* We found one, proceed */
spin_unlock(&last_ptr->refill_lock);
trace_btrfs_reserve_extent_cluster(bg,
ffe_ctl->search_start,
ffe_ctl->num_bytes);
ffe_ctl->found_offset = offset;
return 0;
}
} else if (!ffe_ctl->cached && ffe_ctl->loop > LOOP_CACHING_NOWAIT &&
!ffe_ctl->retry_clustered) {
spin_unlock(&last_ptr->refill_lock);
ffe_ctl->retry_clustered = true;
btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
ffe_ctl->empty_cluster + ffe_ctl->empty_size);
return -EAGAIN;
}
/*
* At this point we either didn't find a cluster or we weren't able to
* allocate a block from our cluster. Free the cluster we've been
* trying to use, and go to the next block group.
*/
btrfs_return_cluster_to_free_space(NULL, last_ptr);
spin_unlock(&last_ptr->refill_lock);
return 1;
}
/*
* Return >0 to inform caller that we find nothing
* Return 0 when we found an free extent and set ffe_ctrl->found_offset
* Return -EAGAIN to inform caller that we need to re-search this block group
*/
static int find_free_extent_unclustered(struct btrfs_block_group_cache *bg,
struct btrfs_free_cluster *last_ptr,
struct find_free_extent_ctl *ffe_ctl)
{
u64 offset;
/*
* We are doing an unclustered allocation, set the fragmented flag so
* we don't bother trying to setup a cluster again until we get more
* space.
*/
if (unlikely(last_ptr)) {
spin_lock(&last_ptr->lock);
last_ptr->fragmented = 1;
spin_unlock(&last_ptr->lock);
}
if (ffe_ctl->cached) {
struct btrfs_free_space_ctl *free_space_ctl;
free_space_ctl = bg->free_space_ctl;
spin_lock(&free_space_ctl->tree_lock);
if (free_space_ctl->free_space <
ffe_ctl->num_bytes + ffe_ctl->empty_cluster +
ffe_ctl->empty_size) {
ffe_ctl->total_free_space = max_t(u64,
ffe_ctl->total_free_space,
free_space_ctl->free_space);
spin_unlock(&free_space_ctl->tree_lock);
return 1;
}
spin_unlock(&free_space_ctl->tree_lock);
}
offset = btrfs_find_space_for_alloc(bg, ffe_ctl->search_start,
ffe_ctl->num_bytes, ffe_ctl->empty_size,
&ffe_ctl->max_extent_size);
/*
* If we didn't find a chunk, and we haven't failed on this block group
* before, and this block group is in the middle of caching and we are
* ok with waiting, then go ahead and wait for progress to be made, and
* set @retry_unclustered to true.
*
* If @retry_unclustered is true then we've already waited on this
* block group once and should move on to the next block group.
*/
if (!offset && !ffe_ctl->retry_unclustered && !ffe_ctl->cached &&
ffe_ctl->loop > LOOP_CACHING_NOWAIT) {
btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
ffe_ctl->empty_size);
ffe_ctl->retry_unclustered = true;
return -EAGAIN;
} else if (!offset) {
return 1;
}
ffe_ctl->found_offset = offset;
return 0;
}
/*
* Return >0 means caller needs to re-search for free extent
* Return 0 means we have the needed free extent.
* Return <0 means we failed to locate any free extent.
*/
static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info,
struct btrfs_free_cluster *last_ptr,
struct btrfs_key *ins,
struct find_free_extent_ctl *ffe_ctl,
int full_search, bool use_cluster)
{
struct btrfs_root *root = fs_info->extent_root;
int ret;
if ((ffe_ctl->loop == LOOP_CACHING_NOWAIT) &&
ffe_ctl->have_caching_bg && !ffe_ctl->orig_have_caching_bg)
ffe_ctl->orig_have_caching_bg = true;
if (!ins->objectid && ffe_ctl->loop >= LOOP_CACHING_WAIT &&
ffe_ctl->have_caching_bg)
return 1;
if (!ins->objectid && ++(ffe_ctl->index) < BTRFS_NR_RAID_TYPES)
return 1;
if (ins->objectid) {
if (!use_cluster && last_ptr) {
spin_lock(&last_ptr->lock);
last_ptr->window_start = ins->objectid;
spin_unlock(&last_ptr->lock);
}
return 0;
}
/*
* LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
* caching kthreads as we move along
* LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
* LOOP_ALLOC_CHUNK, force a chunk allocation and try again
* LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
* again
*/
if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) {
ffe_ctl->index = 0;
if (ffe_ctl->loop == LOOP_CACHING_NOWAIT) {
/*
* We want to skip the LOOP_CACHING_WAIT step if we
* don't have any uncached bgs and we've already done a
* full search through.
*/
if (ffe_ctl->orig_have_caching_bg || !full_search)
ffe_ctl->loop = LOOP_CACHING_WAIT;
else
ffe_ctl->loop = LOOP_ALLOC_CHUNK;
} else {
ffe_ctl->loop++;
}
if (ffe_ctl->loop == LOOP_ALLOC_CHUNK) {
struct btrfs_trans_handle *trans;
int exist = 0;
trans = current->journal_info;
if (trans)
exist = 1;
else
trans = btrfs_join_transaction(root);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
return ret;
}
ret = btrfs_chunk_alloc(trans, ffe_ctl->flags,
CHUNK_ALLOC_FORCE);
/*
* If we can't allocate a new chunk we've already looped
* through at least once, move on to the NO_EMPTY_SIZE
* case.
*/
if (ret == -ENOSPC)
ffe_ctl->loop = LOOP_NO_EMPTY_SIZE;
/* Do not bail out on ENOSPC since we can do more. */
if (ret < 0 && ret != -ENOSPC)
btrfs_abort_transaction(trans, ret);
else
ret = 0;
if (!exist)
btrfs_end_transaction(trans);
if (ret)
return ret;
}
if (ffe_ctl->loop == LOOP_NO_EMPTY_SIZE) {
/*
* Don't loop again if we already have no empty_size and
* no empty_cluster.
*/
if (ffe_ctl->empty_size == 0 &&
ffe_ctl->empty_cluster == 0)
return -ENOSPC;
ffe_ctl->empty_size = 0;
ffe_ctl->empty_cluster = 0;
}
return 1;
}
return -ENOSPC;
}
/*
* walks the btree of allocated extents and find a hole of a given size.
* The key ins is changed to record the hole:
* ins->objectid == start position
* ins->flags = BTRFS_EXTENT_ITEM_KEY
* ins->offset == the size of the hole.
* Any available blocks before search_start are skipped.
*
* If there is no suitable free space, we will record the max size of
* the free space extent currently.
*
* The overall logic and call chain:
*
* find_free_extent()
* |- Iterate through all block groups
* | |- Get a valid block group
* | |- Try to do clustered allocation in that block group
* | |- Try to do unclustered allocation in that block group
* | |- Check if the result is valid
* | | |- If valid, then exit
* | |- Jump to next block group
* |
* |- Push harder to find free extents
* |- If not found, re-iterate all block groups
*/
static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
u64 ram_bytes, u64 num_bytes, u64 empty_size,
u64 hint_byte, struct btrfs_key *ins,
u64 flags, int delalloc)
{
int ret = 0;
struct btrfs_free_cluster *last_ptr = NULL;
struct btrfs_block_group_cache *block_group = NULL;
struct find_free_extent_ctl ffe_ctl = {0};
struct btrfs_space_info *space_info;
bool use_cluster = true;
bool full_search = false;
WARN_ON(num_bytes < fs_info->sectorsize);
ffe_ctl.ram_bytes = ram_bytes;
ffe_ctl.num_bytes = num_bytes;
ffe_ctl.empty_size = empty_size;
ffe_ctl.flags = flags;
ffe_ctl.search_start = 0;
ffe_ctl.retry_clustered = false;
ffe_ctl.retry_unclustered = false;
ffe_ctl.delalloc = delalloc;
ffe_ctl.index = btrfs_bg_flags_to_raid_index(flags);
ffe_ctl.have_caching_bg = false;
ffe_ctl.orig_have_caching_bg = false;
ffe_ctl.found_offset = 0;
ins->type = BTRFS_EXTENT_ITEM_KEY;
ins->objectid = 0;
ins->offset = 0;
trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
space_info = btrfs_find_space_info(fs_info, flags);
if (!space_info) {
btrfs_err(fs_info, "No space info for %llu", flags);
return -ENOSPC;
}
/*
* If our free space is heavily fragmented we may not be able to make
* big contiguous allocations, so instead of doing the expensive search
* for free space, simply return ENOSPC with our max_extent_size so we
* can go ahead and search for a more manageable chunk.
*
* If our max_extent_size is large enough for our allocation simply
* disable clustering since we will likely not be able to find enough
* space to create a cluster and induce latency trying.
*/
if (unlikely(space_info->max_extent_size)) {
spin_lock(&space_info->lock);
if (space_info->max_extent_size &&
num_bytes > space_info->max_extent_size) {
ins->offset = space_info->max_extent_size;
spin_unlock(&space_info->lock);
return -ENOSPC;
} else if (space_info->max_extent_size) {
use_cluster = false;
}
spin_unlock(&space_info->lock);
}
last_ptr = fetch_cluster_info(fs_info, space_info,
&ffe_ctl.empty_cluster);
if (last_ptr) {
spin_lock(&last_ptr->lock);
if (last_ptr->block_group)
hint_byte = last_ptr->window_start;
if (last_ptr->fragmented) {
/*
* We still set window_start so we can keep track of the
* last place we found an allocation to try and save
* some time.
*/
hint_byte = last_ptr->window_start;
use_cluster = false;
}
spin_unlock(&last_ptr->lock);
}
ffe_ctl.search_start = max(ffe_ctl.search_start,
first_logical_byte(fs_info, 0));
ffe_ctl.search_start = max(ffe_ctl.search_start, hint_byte);
if (ffe_ctl.search_start == hint_byte) {
block_group = btrfs_lookup_block_group(fs_info,
ffe_ctl.search_start);
/*
* we don't want to use the block group if it doesn't match our
* allocation bits, or if its not cached.
*
* However if we are re-searching with an ideal block group
* picked out then we don't care that the block group is cached.
*/
if (block_group && block_group_bits(block_group, flags) &&
block_group->cached != BTRFS_CACHE_NO) {
down_read(&space_info->groups_sem);
if (list_empty(&block_group->list) ||
block_group->ro) {
/*
* someone is removing this block group,
* we can't jump into the have_block_group
* target because our list pointers are not
* valid
*/
btrfs_put_block_group(block_group);
up_read(&space_info->groups_sem);
} else {
ffe_ctl.index = btrfs_bg_flags_to_raid_index(
block_group->flags);
btrfs_lock_block_group(block_group, delalloc);
goto have_block_group;
}
} else if (block_group) {
btrfs_put_block_group(block_group);
}
}
search:
ffe_ctl.have_caching_bg = false;
if (ffe_ctl.index == btrfs_bg_flags_to_raid_index(flags) ||
ffe_ctl.index == 0)
full_search = true;
down_read(&space_info->groups_sem);
list_for_each_entry(block_group,
&space_info->block_groups[ffe_ctl.index], list) {
/* If the block group is read-only, we can skip it entirely. */
if (unlikely(block_group->ro))
continue;
btrfs_grab_block_group(block_group, delalloc);
ffe_ctl.search_start = block_group->key.objectid;
/*
* this can happen if we end up cycling through all the
* raid types, but we want to make sure we only allocate
* for the proper type.
*/
if (!block_group_bits(block_group, flags)) {
u64 extra = BTRFS_BLOCK_GROUP_DUP |
BTRFS_BLOCK_GROUP_RAID1_MASK |
BTRFS_BLOCK_GROUP_RAID56_MASK |
BTRFS_BLOCK_GROUP_RAID10;
/*
* if they asked for extra copies and this block group
* doesn't provide them, bail. This does allow us to
* fill raid0 from raid1.
*/
if ((flags & extra) && !(block_group->flags & extra))
goto loop;
/*
* This block group has different flags than we want.
* It's possible that we have MIXED_GROUP flag but no
* block group is mixed. Just skip such block group.
*/
btrfs_release_block_group(block_group, delalloc);
continue;
}
have_block_group:
ffe_ctl.cached = btrfs_block_group_cache_done(block_group);
if (unlikely(!ffe_ctl.cached)) {
ffe_ctl.have_caching_bg = true;
ret = btrfs_cache_block_group(block_group, 0);
BUG_ON(ret < 0);
ret = 0;
}
if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
goto loop;
/*
* Ok we want to try and use the cluster allocator, so
* lets look there
*/
if (last_ptr && use_cluster) {
struct btrfs_block_group_cache *cluster_bg = NULL;
ret = find_free_extent_clustered(block_group, last_ptr,
&ffe_ctl, &cluster_bg);
if (ret == 0) {
if (cluster_bg && cluster_bg != block_group) {
btrfs_release_block_group(block_group,
delalloc);
block_group = cluster_bg;
}
goto checks;
} else if (ret == -EAGAIN) {
goto have_block_group;
} else if (ret > 0) {
goto loop;
}
/* ret == -ENOENT case falls through */
}
ret = find_free_extent_unclustered(block_group, last_ptr,
&ffe_ctl);
if (ret == -EAGAIN)
goto have_block_group;
else if (ret > 0)
goto loop;
/* ret == 0 case falls through */
checks:
ffe_ctl.search_start = round_up(ffe_ctl.found_offset,
fs_info->stripesize);
/* move on to the next group */
if (ffe_ctl.search_start + num_bytes >
block_group->key.objectid + block_group->key.offset) {
btrfs_add_free_space(block_group, ffe_ctl.found_offset,
num_bytes);
goto loop;
}
if (ffe_ctl.found_offset < ffe_ctl.search_start)
btrfs_add_free_space(block_group, ffe_ctl.found_offset,
ffe_ctl.search_start - ffe_ctl.found_offset);
ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
num_bytes, delalloc);
if (ret == -EAGAIN) {
btrfs_add_free_space(block_group, ffe_ctl.found_offset,
num_bytes);
goto loop;
}
btrfs_inc_block_group_reservations(block_group);
/* we are all good, lets return */
ins->objectid = ffe_ctl.search_start;
ins->offset = num_bytes;
trace_btrfs_reserve_extent(block_group, ffe_ctl.search_start,
num_bytes);
btrfs_release_block_group(block_group, delalloc);
break;
loop:
ffe_ctl.retry_clustered = false;
ffe_ctl.retry_unclustered = false;
BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
ffe_ctl.index);
btrfs_release_block_group(block_group, delalloc);
cond_resched();
}
up_read(&space_info->groups_sem);
ret = find_free_extent_update_loop(fs_info, last_ptr, ins, &ffe_ctl,
full_search, use_cluster);
if (ret > 0)
goto search;
if (ret == -ENOSPC) {
/*
* Use ffe_ctl->total_free_space as fallback if we can't find
* any contiguous hole.
*/
if (!ffe_ctl.max_extent_size)
ffe_ctl.max_extent_size = ffe_ctl.total_free_space;
spin_lock(&space_info->lock);
space_info->max_extent_size = ffe_ctl.max_extent_size;
spin_unlock(&space_info->lock);
ins->offset = ffe_ctl.max_extent_size;
}
return ret;
}
/*
* btrfs_reserve_extent - entry point to the extent allocator. Tries to find a
* hole that is at least as big as @num_bytes.
*
* @root - The root that will contain this extent
*
* @ram_bytes - The amount of space in ram that @num_bytes take. This
* is used for accounting purposes. This value differs
* from @num_bytes only in the case of compressed extents.
*
* @num_bytes - Number of bytes to allocate on-disk.
*
* @min_alloc_size - Indicates the minimum amount of space that the
* allocator should try to satisfy. In some cases
* @num_bytes may be larger than what is required and if
* the filesystem is fragmented then allocation fails.
* However, the presence of @min_alloc_size gives a
* chance to try and satisfy the smaller allocation.
*
* @empty_size - A hint that you plan on doing more COW. This is the
* size in bytes the allocator should try to find free
* next to the block it returns. This is just a hint and
* may be ignored by the allocator.
*
* @hint_byte - Hint to the allocator to start searching above the byte
* address passed. It might be ignored.
*
* @ins - This key is modified to record the found hole. It will
* have the following values:
* ins->objectid == start position
* ins->flags = BTRFS_EXTENT_ITEM_KEY
* ins->offset == the size of the hole.
*
* @is_data - Boolean flag indicating whether an extent is
* allocated for data (true) or metadata (false)
*
* @delalloc - Boolean flag indicating whether this allocation is for
* delalloc or not. If 'true' data_rwsem of block groups
* is going to be acquired.
*
*
* Returns 0 when an allocation succeeded or < 0 when an error occurred. In
* case -ENOSPC is returned then @ins->offset will contain the size of the
* largest available hole the allocator managed to find.
*/
int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
u64 num_bytes, u64 min_alloc_size,
u64 empty_size, u64 hint_byte,
struct btrfs_key *ins, int is_data, int delalloc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
bool final_tried = num_bytes == min_alloc_size;
u64 flags;
int ret;
flags = get_alloc_profile_by_root(root, is_data);
again:
WARN_ON(num_bytes < fs_info->sectorsize);
ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
hint_byte, ins, flags, delalloc);
if (!ret && !is_data) {
btrfs_dec_block_group_reservations(fs_info, ins->objectid);
} else if (ret == -ENOSPC) {
if (!final_tried && ins->offset) {
num_bytes = min(num_bytes >> 1, ins->offset);
num_bytes = round_down(num_bytes,
fs_info->sectorsize);
num_bytes = max(num_bytes, min_alloc_size);
ram_bytes = num_bytes;
if (num_bytes == min_alloc_size)
final_tried = true;
goto again;
} else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
struct btrfs_space_info *sinfo;
sinfo = btrfs_find_space_info(fs_info, flags);
btrfs_err(fs_info,
"allocation failed flags %llu, wanted %llu",
flags, num_bytes);
if (sinfo)
btrfs_dump_space_info(fs_info, sinfo,
num_bytes, 1);
}
}
return ret;
}
static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
u64 start, u64 len,
int pin, int delalloc)
{
struct btrfs_block_group_cache *cache;
int ret = 0;
cache = btrfs_lookup_block_group(fs_info, start);
if (!cache) {
btrfs_err(fs_info, "Unable to find block group for %llu",
start);
return -ENOSPC;
}
if (pin)
pin_down_extent(cache, start, len, 1);
else {
if (btrfs_test_opt(fs_info, DISCARD))
ret = btrfs_discard_extent(fs_info, start, len, NULL);
btrfs_add_free_space(cache, start, len);
btrfs_free_reserved_bytes(cache, len, delalloc);
trace_btrfs_reserved_extent_free(fs_info, start, len);
}
btrfs_put_block_group(cache);
return ret;
}
int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
u64 start, u64 len, int delalloc)
{
return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
}
int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
u64 start, u64 len)
{
return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
}
static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
u64 parent, u64 root_objectid,
u64 flags, u64 owner, u64 offset,
struct btrfs_key *ins, int ref_mod)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
struct btrfs_extent_item *extent_item;
struct btrfs_extent_inline_ref *iref;
struct btrfs_path *path;
struct extent_buffer *leaf;
int type;
u32 size;
if (parent > 0)
type = BTRFS_SHARED_DATA_REF_KEY;
else
type = BTRFS_EXTENT_DATA_REF_KEY;
size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
ins, size);
if (ret) {
btrfs_free_path(path);
return ret;
}
leaf = path->nodes[0];
extent_item = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item);
btrfs_set_extent_refs(leaf, extent_item, ref_mod);
btrfs_set_extent_generation(leaf, extent_item, trans->transid);
btrfs_set_extent_flags(leaf, extent_item,
flags | BTRFS_EXTENT_FLAG_DATA);
iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
btrfs_set_extent_inline_ref_type(leaf, iref, type);
if (parent > 0) {
struct btrfs_shared_data_ref *ref;
ref = (struct btrfs_shared_data_ref *)(iref + 1);
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
} else {
struct btrfs_extent_data_ref *ref;
ref = (struct btrfs_extent_data_ref *)(&iref->offset);
btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
btrfs_set_extent_data_ref_offset(leaf, ref, offset);
btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
}
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_free_path(path);
ret = remove_from_free_space_tree(trans, ins->objectid, ins->offset);
if (ret)
return ret;
ret = update_block_group(trans, ins->objectid, ins->offset, 1);
if (ret) { /* -ENOENT, logic error */
btrfs_err(fs_info, "update block group failed for %llu %llu",
ins->objectid, ins->offset);
BUG();
}
trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
return ret;
}
static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
struct btrfs_extent_item *extent_item;
struct btrfs_key extent_key;
struct btrfs_tree_block_info *block_info;
struct btrfs_extent_inline_ref *iref;
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_delayed_tree_ref *ref;
u32 size = sizeof(*extent_item) + sizeof(*iref);
u64 num_bytes;
u64 flags = extent_op->flags_to_set;
bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
ref = btrfs_delayed_node_to_tree_ref(node);
extent_key.objectid = node->bytenr;
if (skinny_metadata) {
extent_key.offset = ref->level;
extent_key.type = BTRFS_METADATA_ITEM_KEY;
num_bytes = fs_info->nodesize;
} else {
extent_key.offset = node->num_bytes;
extent_key.type = BTRFS_EXTENT_ITEM_KEY;
size += sizeof(*block_info);
num_bytes = node->num_bytes;
}
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
&extent_key, size);
if (ret) {
btrfs_free_path(path);
return ret;
}
leaf = path->nodes[0];
extent_item = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item);
btrfs_set_extent_refs(leaf, extent_item, 1);
btrfs_set_extent_generation(leaf, extent_item, trans->transid);
btrfs_set_extent_flags(leaf, extent_item,
flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
if (skinny_metadata) {
iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
} else {
block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
btrfs_set_tree_block_level(leaf, block_info, ref->level);
iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
}
if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
btrfs_set_extent_inline_ref_type(leaf, iref,
BTRFS_SHARED_BLOCK_REF_KEY);
btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent);
} else {
btrfs_set_extent_inline_ref_type(leaf, iref,
BTRFS_TREE_BLOCK_REF_KEY);
btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root);
}
btrfs_mark_buffer_dirty(leaf);
btrfs_free_path(path);
ret = remove_from_free_space_tree(trans, extent_key.objectid,
num_bytes);
if (ret)
return ret;
ret = update_block_group(trans, extent_key.objectid,
fs_info->nodesize, 1);
if (ret) { /* -ENOENT, logic error */
btrfs_err(fs_info, "update block group failed for %llu %llu",
extent_key.objectid, extent_key.offset);
BUG();
}
trace_btrfs_reserved_extent_alloc(fs_info, extent_key.objectid,
fs_info->nodesize);
return ret;
}
int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 owner,
u64 offset, u64 ram_bytes,
struct btrfs_key *ins)
{
struct btrfs_ref generic_ref = { 0 };
int ret;
BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
ins->objectid, ins->offset, 0);
btrfs_init_data_ref(&generic_ref, root->root_key.objectid, owner, offset);
btrfs_ref_tree_mod(root->fs_info, &generic_ref);
ret = btrfs_add_delayed_data_ref(trans, &generic_ref,
ram_bytes, NULL, NULL);
return ret;
}
/*
* this is used by the tree logging recovery code. It records that
* an extent has been allocated and makes sure to clear the free
* space cache bits as well
*/
int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
u64 root_objectid, u64 owner, u64 offset,
struct btrfs_key *ins)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
struct btrfs_block_group_cache *block_group;
struct btrfs_space_info *space_info;
/*
* Mixed block groups will exclude before processing the log so we only
* need to do the exclude dance if this fs isn't mixed.
*/
if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
ret = __exclude_logged_extent(fs_info, ins->objectid,
ins->offset);
if (ret)
return ret;
}
block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
if (!block_group)
return -EINVAL;
space_info = block_group->space_info;
spin_lock(&space_info->lock);
spin_lock(&block_group->lock);
space_info->bytes_reserved += ins->offset;
block_group->reserved += ins->offset;
spin_unlock(&block_group->lock);
spin_unlock(&space_info->lock);
ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
offset, ins, 1);
btrfs_put_block_group(block_group);
return ret;
}
static struct extent_buffer *
btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
u64 bytenr, int level, u64 owner)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct extent_buffer *buf;
buf = btrfs_find_create_tree_block(fs_info, bytenr);
if (IS_ERR(buf))
return buf;
/*
* Extra safety check in case the extent tree is corrupted and extent
* allocator chooses to use a tree block which is already used and
* locked.
*/
if (buf->lock_owner == current->pid) {
btrfs_err_rl(fs_info,
"tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
buf->start, btrfs_header_owner(buf), current->pid);
free_extent_buffer(buf);
return ERR_PTR(-EUCLEAN);
}
btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
btrfs_tree_lock(buf);
btrfs_clean_tree_block(buf);
clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
btrfs_set_lock_blocking_write(buf);
set_extent_buffer_uptodate(buf);
memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
btrfs_set_header_level(buf, level);
btrfs_set_header_bytenr(buf, buf->start);
btrfs_set_header_generation(buf, trans->transid);
btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
btrfs_set_header_owner(buf, owner);
write_extent_buffer_fsid(buf, fs_info->fs_devices->metadata_uuid);
write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);
if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
buf->log_index = root->log_transid % 2;
/*
* we allow two log transactions at a time, use different
* EXTENT bit to differentiate dirty pages.
*/
if (buf->log_index == 0)
set_extent_dirty(&root->dirty_log_pages, buf->start,
buf->start + buf->len - 1, GFP_NOFS);
else
set_extent_new(&root->dirty_log_pages, buf->start,
buf->start + buf->len - 1);
} else {
buf->log_index = -1;
set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
buf->start + buf->len - 1, GFP_NOFS);
}
trans->dirty = true;
/* this returns a buffer locked for blocking */
return buf;
}
/*
* finds a free extent and does all the dirty work required for allocation
* returns the tree buffer or an ERR_PTR on error.
*/
struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 parent, u64 root_objectid,
const struct btrfs_disk_key *key,
int level, u64 hint,
u64 empty_size)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_key ins;
struct btrfs_block_rsv *block_rsv;
struct extent_buffer *buf;
struct btrfs_delayed_extent_op *extent_op;
struct btrfs_ref generic_ref = { 0 };
u64 flags = 0;
int ret;
u32 blocksize = fs_info->nodesize;
bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
if (btrfs_is_testing(fs_info)) {
buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
level, root_objectid);
if (!IS_ERR(buf))
root->alloc_bytenr += blocksize;
return buf;
}
#endif
block_rsv = btrfs_use_block_rsv(trans, root, blocksize);
if (IS_ERR(block_rsv))
return ERR_CAST(block_rsv);
ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
empty_size, hint, &ins, 0, 0);
if (ret)
goto out_unuse;
buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
root_objectid);
if (IS_ERR(buf)) {
ret = PTR_ERR(buf);
goto out_free_reserved;
}
if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
if (parent == 0)
parent = ins.objectid;
flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
} else
BUG_ON(parent > 0);
if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
extent_op = btrfs_alloc_delayed_extent_op();
if (!extent_op) {
ret = -ENOMEM;
goto out_free_buf;
}
if (key)
memcpy(&extent_op->key, key, sizeof(extent_op->key));
else
memset(&extent_op->key, 0, sizeof(extent_op->key));
extent_op->flags_to_set = flags;
extent_op->update_key = skinny_metadata ? false : true;
extent_op->update_flags = true;
extent_op->is_data = false;
extent_op->level = level;
btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
ins.objectid, ins.offset, parent);
generic_ref.real_root = root->root_key.objectid;
btrfs_init_tree_ref(&generic_ref, level, root_objectid);
btrfs_ref_tree_mod(fs_info, &generic_ref);
ret = btrfs_add_delayed_tree_ref(trans, &generic_ref,
extent_op, NULL, NULL);
if (ret)
goto out_free_delayed;
}
return buf;
out_free_delayed:
btrfs_free_delayed_extent_op(extent_op);
out_free_buf:
free_extent_buffer(buf);
out_free_reserved:
btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
out_unuse:
btrfs_unuse_block_rsv(fs_info, block_rsv, blocksize);
return ERR_PTR(ret);
}
struct walk_control {
u64 refs[BTRFS_MAX_LEVEL];
u64 flags[BTRFS_MAX_LEVEL];
struct btrfs_key update_progress;
struct btrfs_key drop_progress;
int drop_level;
int stage;
int level;
int shared_level;
int update_ref;
int keep_locks;
int reada_slot;
int reada_count;
int restarted;
};
#define DROP_REFERENCE 1
#define UPDATE_BACKREF 2
static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct walk_control *wc,
struct btrfs_path *path)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 bytenr;
u64 generation;
u64 refs;
u64 flags;
u32 nritems;
struct btrfs_key key;
struct extent_buffer *eb;
int ret;
int slot;
int nread = 0;
if (path->slots[wc->level] < wc->reada_slot) {
wc->reada_count = wc->reada_count * 2 / 3;
wc->reada_count = max(wc->reada_count, 2);
} else {
wc->reada_count = wc->reada_count * 3 / 2;
wc->reada_count = min_t(int, wc->reada_count,
BTRFS_NODEPTRS_PER_BLOCK(fs_info));
}
eb = path->nodes[wc->level];
nritems = btrfs_header_nritems(eb);
for (slot = path->slots[wc->level]; slot < nritems; slot++) {
if (nread >= wc->reada_count)
break;
cond_resched();
bytenr = btrfs_node_blockptr(eb, slot);
generation = btrfs_node_ptr_generation(eb, slot);
if (slot == path->slots[wc->level])
goto reada;
if (wc->stage == UPDATE_BACKREF &&
generation <= root->root_key.offset)
continue;
/* We don't lock the tree block, it's OK to be racy here */
ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
wc->level - 1, 1, &refs,
&flags);
/* We don't care about errors in readahead. */
if (ret < 0)
continue;
BUG_ON(refs == 0);
if (wc->stage == DROP_REFERENCE) {
if (refs == 1)
goto reada;
if (wc->level == 1 &&
(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
continue;
if (!wc->update_ref ||
generation <= root->root_key.offset)
continue;
btrfs_node_key_to_cpu(eb, &key, slot);
ret = btrfs_comp_cpu_keys(&key,
&wc->update_progress);
if (ret < 0)
continue;
} else {
if (wc->level == 1 &&
(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
continue;
}
reada:
readahead_tree_block(fs_info, bytenr);
nread++;
}
wc->reada_slot = slot;
}
/*
* helper to process tree block while walking down the tree.
*
* when wc->stage == UPDATE_BACKREF, this function updates
* back refs for pointers in the block.
*
* NOTE: return value 1 means we should stop walking down.
*/
static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc, int lookup_info)
{
struct btrfs_fs_info *fs_info = root->fs_info;
int level = wc->level;
struct extent_buffer *eb = path->nodes[level];
u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
int ret;
if (wc->stage == UPDATE_BACKREF &&
btrfs_header_owner(eb) != root->root_key.objectid)
return 1;
/*
* when reference count of tree block is 1, it won't increase
* again. once full backref flag is set, we never clear it.
*/
if (lookup_info &&
((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
(wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
BUG_ON(!path->locks[level]);
ret = btrfs_lookup_extent_info(trans, fs_info,
eb->start, level, 1,
&wc->refs[level],
&wc->flags[level]);
BUG_ON(ret == -ENOMEM);
if (ret)
return ret;
BUG_ON(wc->refs[level] == 0);
}
if (wc->stage == DROP_REFERENCE) {
if (wc->refs[level] > 1)
return 1;
if (path->locks[level] && !wc->keep_locks) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
path->locks[level] = 0;
}
return 0;
}
/* wc->stage == UPDATE_BACKREF */
if (!(wc->flags[level] & flag)) {
BUG_ON(!path->locks[level]);
ret = btrfs_inc_ref(trans, root, eb, 1);
BUG_ON(ret); /* -ENOMEM */
ret = btrfs_dec_ref(trans, root, eb, 0);
BUG_ON(ret); /* -ENOMEM */
ret = btrfs_set_disk_extent_flags(trans, eb->start,
eb->len, flag,
btrfs_header_level(eb), 0);
BUG_ON(ret); /* -ENOMEM */
wc->flags[level] |= flag;
}
/*
* the block is shared by multiple trees, so it's not good to
* keep the tree lock
*/
if (path->locks[level] && level > 0) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
path->locks[level] = 0;
}
return 0;
}
/*
* This is used to verify a ref exists for this root to deal with a bug where we
* would have a drop_progress key that hadn't been updated properly.
*/
static int check_ref_exists(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 bytenr, u64 parent,
int level)
{
struct btrfs_path *path;
struct btrfs_extent_inline_ref *iref;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
ret = lookup_extent_backref(trans, path, &iref, bytenr,
root->fs_info->nodesize, parent,
root->root_key.objectid, level, 0);
btrfs_free_path(path);
if (ret == -ENOENT)
return 0;
if (ret < 0)
return ret;
return 1;
}
/*
* helper to process tree block pointer.
*
* when wc->stage == DROP_REFERENCE, this function checks
* reference count of the block pointed to. if the block
* is shared and we need update back refs for the subtree
* rooted at the block, this function changes wc->stage to
* UPDATE_BACKREF. if the block is shared and there is no
* need to update back, this function drops the reference
* to the block.
*
* NOTE: return value 1 means we should stop walking down.
*/
static noinline int do_walk_down(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc, int *lookup_info)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 bytenr;
u64 generation;
u64 parent;
struct btrfs_key key;
struct btrfs_key first_key;
struct btrfs_ref ref = { 0 };
struct extent_buffer *next;
int level = wc->level;
int reada = 0;
int ret = 0;
bool need_account = false;
generation = btrfs_node_ptr_generation(path->nodes[level],
path->slots[level]);
/*
* if the lower level block was created before the snapshot
* was created, we know there is no need to update back refs
* for the subtree
*/
if (wc->stage == UPDATE_BACKREF &&
generation <= root->root_key.offset) {
*lookup_info = 1;
return 1;
}
bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
btrfs_node_key_to_cpu(path->nodes[level], &first_key,
path->slots[level]);
next = find_extent_buffer(fs_info, bytenr);
if (!next) {
next = btrfs_find_create_tree_block(fs_info, bytenr);
if (IS_ERR(next))
return PTR_ERR(next);
btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
level - 1);
reada = 1;
}
btrfs_tree_lock(next);
btrfs_set_lock_blocking_write(next);
ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
&wc->refs[level - 1],
&wc->flags[level - 1]);
if (ret < 0)
goto out_unlock;
if (unlikely(wc->refs[level - 1] == 0)) {
btrfs_err(fs_info, "Missing references.");
ret = -EIO;
goto out_unlock;
}
*lookup_info = 0;
if (wc->stage == DROP_REFERENCE) {
if (wc->refs[level - 1] > 1) {
need_account = true;
if (level == 1 &&
(wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
goto skip;
if (!wc->update_ref ||
generation <= root->root_key.offset)
goto skip;
btrfs_node_key_to_cpu(path->nodes[level], &key,
path->slots[level]);
ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
if (ret < 0)
goto skip;
wc->stage = UPDATE_BACKREF;
wc->shared_level = level - 1;
}
} else {
if (level == 1 &&
(wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
goto skip;
}
if (!btrfs_buffer_uptodate(next, generation, 0)) {
btrfs_tree_unlock(next);
free_extent_buffer(next);
next = NULL;
*lookup_info = 1;
}
if (!next) {
if (reada && level == 1)
reada_walk_down(trans, root, wc, path);
next = read_tree_block(fs_info, bytenr, generation, level - 1,
&first_key);
if (IS_ERR(next)) {
return PTR_ERR(next);
} else if (!extent_buffer_uptodate(next)) {
free_extent_buffer(next);
return -EIO;
}
btrfs_tree_lock(next);
btrfs_set_lock_blocking_write(next);
}
level--;
ASSERT(level == btrfs_header_level(next));
if (level != btrfs_header_level(next)) {
btrfs_err(root->fs_info, "mismatched level");
ret = -EIO;
goto out_unlock;
}
path->nodes[level] = next;
path->slots[level] = 0;
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
wc->level = level;
if (wc->level == 1)
wc->reada_slot = 0;
return 0;
skip:
wc->refs[level - 1] = 0;
wc->flags[level - 1] = 0;
if (wc->stage == DROP_REFERENCE) {
if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
parent = path->nodes[level]->start;
} else {
ASSERT(root->root_key.objectid ==
btrfs_header_owner(path->nodes[level]));
if (root->root_key.objectid !=
btrfs_header_owner(path->nodes[level])) {
btrfs_err(root->fs_info,
"mismatched block owner");
ret = -EIO;
goto out_unlock;
}
parent = 0;
}
/*
* If we had a drop_progress we need to verify the refs are set
* as expected. If we find our ref then we know that from here
* on out everything should be correct, and we can clear the
* ->restarted flag.
*/
if (wc->restarted) {
ret = check_ref_exists(trans, root, bytenr, parent,
level - 1);
if (ret < 0)
goto out_unlock;
if (ret == 0)
goto no_delete;
ret = 0;
wc->restarted = 0;
}
/*
* Reloc tree doesn't contribute to qgroup numbers, and we have
* already accounted them at merge time (replace_path),
* thus we could skip expensive subtree trace here.
*/
if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
need_account) {
ret = btrfs_qgroup_trace_subtree(trans, next,
generation, level - 1);
if (ret) {
btrfs_err_rl(fs_info,
"Error %d accounting shared subtree. Quota is out of sync, rescan required.",
ret);
}
}
/*
* We need to update the next key in our walk control so we can
* update the drop_progress key accordingly. We don't care if
* find_next_key doesn't find a key because that means we're at
* the end and are going to clean up now.
*/
wc->drop_level = level;
find_next_key(path, level, &wc->drop_progress);
btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
fs_info->nodesize, parent);
btrfs_init_tree_ref(&ref, level - 1, root->root_key.objectid);
ret = btrfs_free_extent(trans, &ref);
if (ret)
goto out_unlock;
}
no_delete:
*lookup_info = 1;
ret = 1;
out_unlock:
btrfs_tree_unlock(next);
free_extent_buffer(next);
return ret;
}
/*
* helper to process tree block while walking up the tree.
*
* when wc->stage == DROP_REFERENCE, this function drops
* reference count on the block.
*
* when wc->stage == UPDATE_BACKREF, this function changes
* wc->stage back to DROP_REFERENCE if we changed wc->stage
* to UPDATE_BACKREF previously while processing the block.
*
* NOTE: return value 1 means we should stop walking up.
*/
static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
int ret;
int level = wc->level;
struct extent_buffer *eb = path->nodes[level];
u64 parent = 0;
if (wc->stage == UPDATE_BACKREF) {
BUG_ON(wc->shared_level < level);
if (level < wc->shared_level)
goto out;
ret = find_next_key(path, level + 1, &wc->update_progress);
if (ret > 0)
wc->update_ref = 0;
wc->stage = DROP_REFERENCE;
wc->shared_level = -1;
path->slots[level] = 0;
/*
* check reference count again if the block isn't locked.
* we should start walking down the tree again if reference
* count is one.
*/
if (!path->locks[level]) {
BUG_ON(level == 0);
btrfs_tree_lock(eb);
btrfs_set_lock_blocking_write(eb);
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
ret = btrfs_lookup_extent_info(trans, fs_info,
eb->start, level, 1,
&wc->refs[level],
&wc->flags[level]);
if (ret < 0) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
path->locks[level] = 0;
return ret;
}
BUG_ON(wc->refs[level] == 0);
if (wc->refs[level] == 1) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
path->locks[level] = 0;
return 1;
}
}
}
/* wc->stage == DROP_REFERENCE */
BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
if (wc->refs[level] == 1) {
if (level == 0) {
if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
ret = btrfs_dec_ref(trans, root, eb, 1);
else
ret = btrfs_dec_ref(trans, root, eb, 0);
BUG_ON(ret); /* -ENOMEM */
if (is_fstree(root->root_key.objectid)) {
ret = btrfs_qgroup_trace_leaf_items(trans, eb);
if (ret) {
btrfs_err_rl(fs_info,
"error %d accounting leaf items, quota is out of sync, rescan required",
ret);
}
}
}
/* make block locked assertion in btrfs_clean_tree_block happy */
if (!path->locks[level] &&
btrfs_header_generation(eb) == trans->transid) {
btrfs_tree_lock(eb);
btrfs_set_lock_blocking_write(eb);
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
}
btrfs_clean_tree_block(eb);
}
if (eb == root->node) {
if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
parent = eb->start;
else if (root->root_key.objectid != btrfs_header_owner(eb))
goto owner_mismatch;
} else {
if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
parent = path->nodes[level + 1]->start;
else if (root->root_key.objectid !=
btrfs_header_owner(path->nodes[level + 1]))
goto owner_mismatch;
}
btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
out:
wc->refs[level] = 0;
wc->flags[level] = 0;
return 0;
owner_mismatch:
btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
btrfs_header_owner(eb), root->root_key.objectid);
return -EUCLEAN;
}
static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc)
{
int level = wc->level;
int lookup_info = 1;
int ret;
while (level >= 0) {
ret = walk_down_proc(trans, root, path, wc, lookup_info);
if (ret > 0)
break;
if (level == 0)
break;
if (path->slots[level] >=
btrfs_header_nritems(path->nodes[level]))
break;
ret = do_walk_down(trans, root, path, wc, &lookup_info);
if (ret > 0) {
path->slots[level]++;
continue;
} else if (ret < 0)
return ret;
level = wc->level;
}
return 0;
}
static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc, int max_level)
{
int level = wc->level;
int ret;
path->slots[level] = btrfs_header_nritems(path->nodes[level]);
while (level < max_level && path->nodes[level]) {
wc->level = level;
if (path->slots[level] + 1 <
btrfs_header_nritems(path->nodes[level])) {
path->slots[level]++;
return 0;
} else {
ret = walk_up_proc(trans, root, path, wc);
if (ret > 0)
return 0;
if (ret < 0)
return ret;
if (path->locks[level]) {
btrfs_tree_unlock_rw(path->nodes[level],
path->locks[level]);
path->locks[level] = 0;
}
free_extent_buffer(path->nodes[level]);
path->nodes[level] = NULL;
level++;
}
}
return 1;
}
/*
* drop a subvolume tree.
*
* this function traverses the tree freeing any blocks that only
* referenced by the tree.
*
* when a shared tree block is found. this function decreases its
* reference count by one. if update_ref is true, this function
* also make sure backrefs for the shared block and all lower level
* blocks are properly updated.
*
* If called with for_reloc == 0, may exit early with -EAGAIN
*/
int btrfs_drop_snapshot(struct btrfs_root *root,
struct btrfs_block_rsv *block_rsv, int update_ref,
int for_reloc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_path *path;
struct btrfs_trans_handle *trans;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root_item *root_item = &root->root_item;
struct walk_control *wc;
struct btrfs_key key;
int err = 0;
int ret;
int level;
bool root_dropped = false;
btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid);
path = btrfs_alloc_path();
if (!path) {
err = -ENOMEM;
goto out;
}
wc = kzalloc(sizeof(*wc), GFP_NOFS);
if (!wc) {
btrfs_free_path(path);
err = -ENOMEM;
goto out;
}
trans = btrfs_start_transaction(tree_root, 0);
if (IS_ERR(trans)) {
err = PTR_ERR(trans);
goto out_free;
}
err = btrfs_run_delayed_items(trans);
if (err)
goto out_end_trans;
if (block_rsv)
trans->block_rsv = block_rsv;
/*
* This will help us catch people modifying the fs tree while we're
* dropping it. It is unsafe to mess with the fs tree while it's being
* dropped as we unlock the root node and parent nodes as we walk down
* the tree, assuming nothing will change. If something does change
* then we'll have stale information and drop references to blocks we've
* already dropped.
*/
set_bit(BTRFS_ROOT_DELETING, &root->state);
if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
level = btrfs_header_level(root->node);
path->nodes[level] = btrfs_lock_root_node(root);
btrfs_set_lock_blocking_write(path->nodes[level]);
path->slots[level] = 0;
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
memset(&wc->update_progress, 0,
sizeof(wc->update_progress));
} else {
btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
memcpy(&wc->update_progress, &key,
sizeof(wc->update_progress));
level = root_item->drop_level;
BUG_ON(level == 0);
path->lowest_level = level;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
path->lowest_level = 0;
if (ret < 0) {
err = ret;
goto out_end_trans;
}
WARN_ON(ret > 0);
/*
* unlock our path, this is safe because only this
* function is allowed to delete this snapshot
*/
btrfs_unlock_up_safe(path, 0);
level = btrfs_header_level(root->node);
while (1) {
btrfs_tree_lock(path->nodes[level]);
btrfs_set_lock_blocking_write(path->nodes[level]);
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
ret = btrfs_lookup_extent_info(trans, fs_info,
path->nodes[level]->start,
level, 1, &wc->refs[level],
&wc->flags[level]);
if (ret < 0) {
err = ret;
goto out_end_trans;
}
BUG_ON(wc->refs[level] == 0);
if (level == root_item->drop_level)
break;
btrfs_tree_unlock(path->nodes[level]);
path->locks[level] = 0;
WARN_ON(wc->refs[level] != 1);
level--;
}
}
wc->restarted = test_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
wc->level = level;
wc->shared_level = -1;
wc->stage = DROP_REFERENCE;
wc->update_ref = update_ref;
wc->keep_locks = 0;
wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
while (1) {
ret = walk_down_tree(trans, root, path, wc);
if (ret < 0) {
err = ret;
break;
}
ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
if (ret < 0) {
err = ret;
break;
}
if (ret > 0) {
BUG_ON(wc->stage != DROP_REFERENCE);
break;
}
if (wc->stage == DROP_REFERENCE) {
wc->drop_level = wc->level;
btrfs_node_key_to_cpu(path->nodes[wc->drop_level],
&wc->drop_progress,
path->slots[wc->drop_level]);
}
btrfs_cpu_key_to_disk(&root_item->drop_progress,
&wc->drop_progress);
root_item->drop_level = wc->drop_level;
BUG_ON(wc->level == 0);
if (btrfs_should_end_transaction(trans) ||
(!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
ret = btrfs_update_root(trans, tree_root,
&root->root_key,
root_item);
if (ret) {
btrfs_abort_transaction(trans, ret);
err = ret;
goto out_end_trans;
}
btrfs_end_transaction_throttle(trans);
if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
btrfs_debug(fs_info,
"drop snapshot early exit");
err = -EAGAIN;
goto out_free;
}
trans = btrfs_start_transaction(tree_root, 0);
if (IS_ERR(trans)) {
err = PTR_ERR(trans);
goto out_free;
}
if (block_rsv)
trans->block_rsv = block_rsv;
}
}
btrfs_release_path(path);
if (err)
goto out_end_trans;
ret = btrfs_del_root(trans, &root->root_key);
if (ret) {
btrfs_abort_transaction(trans, ret);
err = ret;
goto out_end_trans;
}
if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
ret = btrfs_find_root(tree_root, &root->root_key, path,
NULL, NULL);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
err = ret;
goto out_end_trans;
} else if (ret > 0) {
/* if we fail to delete the orphan item this time
* around, it'll get picked up the next time.
*
* The most common failure here is just -ENOENT.
*/
btrfs_del_orphan_item(trans, tree_root,
root->root_key.objectid);
}
}
if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
btrfs_add_dropped_root(trans, root);
} else {
free_extent_buffer(root->node);
free_extent_buffer(root->commit_root);
btrfs_put_fs_root(root);
}
root_dropped = true;
out_end_trans:
btrfs_end_transaction_throttle(trans);
out_free:
kfree(wc);
btrfs_free_path(path);
out:
/*
* So if we need to stop dropping the snapshot for whatever reason we
* need to make sure to add it back to the dead root list so that we
* keep trying to do the work later. This also cleans up roots if we
* don't have it in the radix (like when we recover after a power fail
* or unmount) so we don't leak memory.
*/
if (!for_reloc && !root_dropped)
btrfs_add_dead_root(root);
if (err && err != -EAGAIN)
btrfs_handle_fs_error(fs_info, err, NULL);
return err;
}
/*
* drop subtree rooted at tree block 'node'.
*
* NOTE: this function will unlock and release tree block 'node'
* only used by relocation code
*/
int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *node,
struct extent_buffer *parent)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_path *path;
struct walk_control *wc;
int level;
int parent_level;
int ret = 0;
int wret;
BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
wc = kzalloc(sizeof(*wc), GFP_NOFS);
if (!wc) {
btrfs_free_path(path);
return -ENOMEM;
}
btrfs_assert_tree_locked(parent);
parent_level = btrfs_header_level(parent);
extent_buffer_get(parent);
path->nodes[parent_level] = parent;
path->slots[parent_level] = btrfs_header_nritems(parent);
btrfs_assert_tree_locked(node);
level = btrfs_header_level(node);
path->nodes[level] = node;
path->slots[level] = 0;
path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
wc->refs[parent_level] = 1;
wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
wc->level = level;
wc->shared_level = -1;
wc->stage = DROP_REFERENCE;
wc->update_ref = 0;
wc->keep_locks = 1;
wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
while (1) {
wret = walk_down_tree(trans, root, path, wc);
if (wret < 0) {
ret = wret;
break;
}
wret = walk_up_tree(trans, root, path, wc, parent_level);
if (wret < 0)
ret = wret;
if (wret != 0)
break;
}
kfree(wc);
btrfs_free_path(path);
return ret;
}
static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 num_devices;
u64 stripped;
/*
* if restripe for this chunk_type is on pick target profile and
* return, otherwise do the usual balance
*/
stripped = get_restripe_target(fs_info, flags);
if (stripped)
return extended_to_chunk(stripped);
num_devices = fs_info->fs_devices->rw_devices;
stripped = BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID56_MASK |
BTRFS_BLOCK_GROUP_RAID1_MASK | BTRFS_BLOCK_GROUP_RAID10;
if (num_devices == 1) {
stripped |= BTRFS_BLOCK_GROUP_DUP;
stripped = flags & ~stripped;
/* turn raid0 into single device chunks */
if (flags & BTRFS_BLOCK_GROUP_RAID0)
return stripped;
/* turn mirroring into duplication */
if (flags & (BTRFS_BLOCK_GROUP_RAID1_MASK |
BTRFS_BLOCK_GROUP_RAID10))
return stripped | BTRFS_BLOCK_GROUP_DUP;
} else {
/* they already had raid on here, just return */
if (flags & stripped)
return flags;
stripped |= BTRFS_BLOCK_GROUP_DUP;
stripped = flags & ~stripped;
/* switch duplicated blocks with raid1 */
if (flags & BTRFS_BLOCK_GROUP_DUP)
return stripped | BTRFS_BLOCK_GROUP_RAID1;
/* this is drive concat, leave it alone */
}
return flags;
}
/*
* Mark block group @cache read-only, so later write won't happen to block
* group @cache.
*
* If @force is not set, this function will only mark the block group readonly
* if we have enough free space (1M) in other metadata/system block groups.
* If @force is not set, this function will mark the block group readonly
* without checking free space.
*
* NOTE: This function doesn't care if other block groups can contain all the
* data in this block group. That check should be done by relocation routine,
* not this function.
*/
static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
{
struct btrfs_space_info *sinfo = cache->space_info;
u64 num_bytes;
u64 sinfo_used;
u64 min_allocable_bytes;
int ret = -ENOSPC;
/*
* We need some metadata space and system metadata space for
* allocating chunks in some corner cases until we force to set
* it to be readonly.
*/
if ((sinfo->flags &
(BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
!force)
min_allocable_bytes = SZ_1M;
else
min_allocable_bytes = 0;
spin_lock(&sinfo->lock);
spin_lock(&cache->lock);
if (cache->ro) {
cache->ro++;
ret = 0;
goto out;
}
num_bytes = cache->key.offset - cache->reserved - cache->pinned -
cache->bytes_super - btrfs_block_group_used(&cache->item);
sinfo_used = btrfs_space_info_used(sinfo, true);
/*
* sinfo_used + num_bytes should always <= sinfo->total_bytes.
*
* Here we make sure if we mark this bg RO, we still have enough
* free space as buffer (if min_allocable_bytes is not 0).
*/
if (sinfo_used + num_bytes + min_allocable_bytes <=
sinfo->total_bytes) {
sinfo->bytes_readonly += num_bytes;
cache->ro++;
list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
ret = 0;
}
out:
spin_unlock(&cache->lock);
spin_unlock(&sinfo->lock);
if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) {
btrfs_info(cache->fs_info,
"unable to make block group %llu ro",
cache->key.objectid);
btrfs_info(cache->fs_info,
"sinfo_used=%llu bg_num_bytes=%llu min_allocable=%llu",
sinfo_used, num_bytes, min_allocable_bytes);
btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0);
}
return ret;
}
int btrfs_inc_block_group_ro(struct btrfs_block_group_cache *cache)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
struct btrfs_trans_handle *trans;
u64 alloc_flags;
int ret;
again:
trans = btrfs_join_transaction(fs_info->extent_root);
if (IS_ERR(trans))
return PTR_ERR(trans);
/*
* we're not allowed to set block groups readonly after the dirty
* block groups cache has started writing. If it already started,
* back off and let this transaction commit
*/
mutex_lock(&fs_info->ro_block_group_mutex);
if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
u64 transid = trans->transid;
mutex_unlock(&fs_info->ro_block_group_mutex);
btrfs_end_transaction(trans);
ret = btrfs_wait_for_commit(fs_info, transid);
if (ret)
return ret;
goto again;
}
/*
* if we are changing raid levels, try to allocate a corresponding
* block group with the new raid level.
*/
alloc_flags = update_block_group_flags(fs_info, cache->flags);
if (alloc_flags != cache->flags) {
ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
/*
* ENOSPC is allowed here, we may have enough space
* already allocated at the new raid level to
* carry on
*/
if (ret == -ENOSPC)
ret = 0;
if (ret < 0)
goto out;
}
ret = inc_block_group_ro(cache, 0);
if (!ret)
goto out;
alloc_flags = get_alloc_profile(fs_info, cache->space_info->flags);
ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
if (ret < 0)
goto out;
ret = inc_block_group_ro(cache, 0);
out:
if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
alloc_flags = update_block_group_flags(fs_info, cache->flags);
mutex_lock(&fs_info->chunk_mutex);
check_system_chunk(trans, alloc_flags);
mutex_unlock(&fs_info->chunk_mutex);
}
mutex_unlock(&fs_info->ro_block_group_mutex);
btrfs_end_transaction(trans);
return ret;
}
int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
{
u64 alloc_flags = get_alloc_profile(trans->fs_info, type);
return btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
}
/*
* helper to account the unused space of all the readonly block group in the
* space_info. takes mirrors into account.
*/
u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
{
struct btrfs_block_group_cache *block_group;
u64 free_bytes = 0;
int factor;
/* It's df, we don't care if it's racy */
if (list_empty(&sinfo->ro_bgs))
return 0;
spin_lock(&sinfo->lock);
list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
spin_lock(&block_group->lock);
if (!block_group->ro) {
spin_unlock(&block_group->lock);
continue;
}
factor = btrfs_bg_type_to_factor(block_group->flags);
free_bytes += (block_group->key.offset -
btrfs_block_group_used(&block_group->item)) *
factor;
spin_unlock(&block_group->lock);
}
spin_unlock(&sinfo->lock);
return free_bytes;
}
void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
{
struct btrfs_space_info *sinfo = cache->space_info;
u64 num_bytes;
BUG_ON(!cache->ro);
spin_lock(&sinfo->lock);
spin_lock(&cache->lock);
if (!--cache->ro) {
num_bytes = cache->key.offset - cache->reserved -
cache->pinned - cache->bytes_super -
btrfs_block_group_used(&cache->item);
sinfo->bytes_readonly -= num_bytes;
list_del_init(&cache->ro_list);
}
spin_unlock(&cache->lock);
spin_unlock(&sinfo->lock);
}
static int find_first_block_group(struct btrfs_fs_info *fs_info,
struct btrfs_path *path,
struct btrfs_key *key)
{
struct btrfs_root *root = fs_info->extent_root;
int ret = 0;
struct btrfs_key found_key;
struct extent_buffer *leaf;
struct btrfs_block_group_item bg;
u64 flags;
int slot;
ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
if (ret < 0)
goto out;
while (1) {
slot = path->slots[0];
leaf = path->nodes[0];
if (slot >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, path);
if (ret == 0)
continue;
if (ret < 0)
goto out;
break;
}
btrfs_item_key_to_cpu(leaf, &found_key, slot);
if (found_key.objectid >= key->objectid &&
found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
struct extent_map_tree *em_tree;
struct extent_map *em;
em_tree = &root->fs_info->mapping_tree;
read_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, found_key.objectid,
found_key.offset);
read_unlock(&em_tree->lock);
if (!em) {
btrfs_err(fs_info,
"logical %llu len %llu found bg but no related chunk",
found_key.objectid, found_key.offset);
ret = -ENOENT;
} else if (em->start != found_key.objectid ||
em->len != found_key.offset) {
btrfs_err(fs_info,
"block group %llu len %llu mismatch with chunk %llu len %llu",
found_key.objectid, found_key.offset,
em->start, em->len);
ret = -EUCLEAN;
} else {
read_extent_buffer(leaf, &bg,
btrfs_item_ptr_offset(leaf, slot),
sizeof(bg));
flags = btrfs_block_group_flags(&bg) &
BTRFS_BLOCK_GROUP_TYPE_MASK;
if (flags != (em->map_lookup->type &
BTRFS_BLOCK_GROUP_TYPE_MASK)) {
btrfs_err(fs_info,
"block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
found_key.objectid,
found_key.offset, flags,
(BTRFS_BLOCK_GROUP_TYPE_MASK &
em->map_lookup->type));
ret = -EUCLEAN;
} else {
ret = 0;
}
}
free_extent_map(em);
goto out;
}
path->slots[0]++;
}
out:
return ret;
}
void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
{
struct btrfs_block_group_cache *block_group;
u64 last = 0;
while (1) {
struct inode *inode;
block_group = btrfs_lookup_first_block_group(info, last);
while (block_group) {
btrfs_wait_block_group_cache_done(block_group);
spin_lock(&block_group->lock);
if (block_group->iref)
break;
spin_unlock(&block_group->lock);
block_group = btrfs_next_block_group(block_group);
}
if (!block_group) {
if (last == 0)
break;
last = 0;
continue;
}
inode = block_group->inode;
block_group->iref = 0;
block_group->inode = NULL;
spin_unlock(&block_group->lock);
ASSERT(block_group->io_ctl.inode == NULL);
iput(inode);
last = block_group->key.objectid + block_group->key.offset;
btrfs_put_block_group(block_group);
}
}
/*
* Must be called only after stopping all workers, since we could have block
* group caching kthreads running, and therefore they could race with us if we
* freed the block groups before stopping them.
*/
int btrfs_free_block_groups(struct btrfs_fs_info *info)
{
struct btrfs_block_group_cache *block_group;
struct btrfs_space_info *space_info;
struct btrfs_caching_control *caching_ctl;
struct rb_node *n;
down_write(&info->commit_root_sem);
while (!list_empty(&info->caching_block_groups)) {
caching_ctl = list_entry(info->caching_block_groups.next,
struct btrfs_caching_control, list);
list_del(&caching_ctl->list);
btrfs_put_caching_control(caching_ctl);
}
up_write(&info->commit_root_sem);
spin_lock(&info->unused_bgs_lock);
while (!list_empty(&info->unused_bgs)) {
block_group = list_first_entry(&info->unused_bgs,
struct btrfs_block_group_cache,
bg_list);
list_del_init(&block_group->bg_list);
btrfs_put_block_group(block_group);
}
spin_unlock(&info->unused_bgs_lock);
spin_lock(&info->block_group_cache_lock);
while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
block_group = rb_entry(n, struct btrfs_block_group_cache,
cache_node);
rb_erase(&block_group->cache_node,
&info->block_group_cache_tree);
RB_CLEAR_NODE(&block_group->cache_node);
spin_unlock(&info->block_group_cache_lock);
down_write(&block_group->space_info->groups_sem);
list_del(&block_group->list);
up_write(&block_group->space_info->groups_sem);
/*
* We haven't cached this block group, which means we could
* possibly have excluded extents on this block group.
*/
if (block_group->cached == BTRFS_CACHE_NO ||
block_group->cached == BTRFS_CACHE_ERROR)
btrfs_free_excluded_extents(block_group);
btrfs_remove_free_space_cache(block_group);
ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
ASSERT(list_empty(&block_group->dirty_list));
ASSERT(list_empty(&block_group->io_list));
ASSERT(list_empty(&block_group->bg_list));
ASSERT(atomic_read(&block_group->count) == 1);
btrfs_put_block_group(block_group);
spin_lock(&info->block_group_cache_lock);
}
spin_unlock(&info->block_group_cache_lock);
/* now that all the block groups are freed, go through and
* free all the space_info structs. This is only called during
* the final stages of unmount, and so we know nobody is
* using them. We call synchronize_rcu() once before we start,
* just to be on the safe side.
*/
synchronize_rcu();
btrfs_release_global_block_rsv(info);
while (!list_empty(&info->space_info)) {
int i;
space_info = list_entry(info->space_info.next,
struct btrfs_space_info,
list);
/*
* Do not hide this behind enospc_debug, this is actually
* important and indicates a real bug if this happens.
*/
if (WARN_ON(space_info->bytes_pinned > 0 ||
space_info->bytes_reserved > 0 ||
space_info->bytes_may_use > 0))
btrfs_dump_space_info(info, space_info, 0, 0);
list_del(&space_info->list);
for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
struct kobject *kobj;
kobj = space_info->block_group_kobjs[i];
space_info->block_group_kobjs[i] = NULL;
if (kobj) {
kobject_del(kobj);
kobject_put(kobj);
}
}
kobject_del(&space_info->kobj);
kobject_put(&space_info->kobj);
}
return 0;
}
static void link_block_group(struct btrfs_block_group_cache *cache)
{
struct btrfs_space_info *space_info = cache->space_info;
struct btrfs_fs_info *fs_info = cache->fs_info;
int index = btrfs_bg_flags_to_raid_index(cache->flags);
bool first = false;
down_write(&space_info->groups_sem);
if (list_empty(&space_info->block_groups[index]))
first = true;
list_add_tail(&cache->list, &space_info->block_groups[index]);
up_write(&space_info->groups_sem);
if (first) {
struct raid_kobject *rkobj;
unsigned int nofs_flag;
int ret;
/*
* Setup a NOFS context because kobject_add(), deep in its call
* chain, does GFP_KERNEL allocations, and we are often called
* in a context where if reclaim is triggered we can deadlock
* (we are either holding a transaction handle or some lock
* required for a transaction commit).
*/
nofs_flag = memalloc_nofs_save();
rkobj = kzalloc(sizeof(*rkobj), GFP_KERNEL);
if (!rkobj) {
memalloc_nofs_restore(nofs_flag);
btrfs_warn(cache->fs_info,
"couldn't alloc memory for raid level kobject");
return;
}
rkobj->flags = cache->flags;
kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
btrfs_bg_type_to_raid_name(rkobj->flags));
memalloc_nofs_restore(nofs_flag);
if (ret) {
kobject_put(&rkobj->kobj);
btrfs_warn(fs_info,
"failed to add kobject for block cache, ignoring");
return;
}
space_info->block_group_kobjs[index] = &rkobj->kobj;
}
}
static struct btrfs_block_group_cache *
btrfs_create_block_group_cache(struct btrfs_fs_info *fs_info,
u64 start, u64 size)
{
struct btrfs_block_group_cache *cache;
cache = kzalloc(sizeof(*cache), GFP_NOFS);
if (!cache)
return NULL;
cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
GFP_NOFS);
if (!cache->free_space_ctl) {
kfree(cache);
return NULL;
}
cache->key.objectid = start;
cache->key.offset = size;
cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
cache->fs_info = fs_info;
cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
set_free_space_tree_thresholds(cache);
atomic_set(&cache->count, 1);
spin_lock_init(&cache->lock);
init_rwsem(&cache->data_rwsem);
INIT_LIST_HEAD(&cache->list);
INIT_LIST_HEAD(&cache->cluster_list);
INIT_LIST_HEAD(&cache->bg_list);
INIT_LIST_HEAD(&cache->ro_list);
INIT_LIST_HEAD(&cache->dirty_list);
INIT_LIST_HEAD(&cache->io_list);
btrfs_init_free_space_ctl(cache);
atomic_set(&cache->trimming, 0);
mutex_init(&cache->free_space_lock);
btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
return cache;
}
/*
* Iterate all chunks and verify that each of them has the corresponding block
* group
*/
static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
{
struct extent_map_tree *map_tree = &fs_info->mapping_tree;
struct extent_map *em;
struct btrfs_block_group_cache *bg;
u64 start = 0;
int ret = 0;
while (1) {
read_lock(&map_tree->lock);
/*
* lookup_extent_mapping will return the first extent map
* intersecting the range, so setting @len to 1 is enough to
* get the first chunk.
*/
em = lookup_extent_mapping(map_tree, start, 1);
read_unlock(&map_tree->lock);
if (!em)
break;
bg = btrfs_lookup_block_group(fs_info, em->start);
if (!bg) {
btrfs_err(fs_info,
"chunk start=%llu len=%llu doesn't have corresponding block group",
em->start, em->len);
ret = -EUCLEAN;
free_extent_map(em);
break;
}
if (bg->key.objectid != em->start ||
bg->key.offset != em->len ||
(bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
(em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
btrfs_err(fs_info,
"chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
em->start, em->len,
em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
bg->key.objectid, bg->key.offset,
bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
ret = -EUCLEAN;
free_extent_map(em);
btrfs_put_block_group(bg);
break;
}
start = em->start + em->len;
free_extent_map(em);
btrfs_put_block_group(bg);
}
return ret;
}
int btrfs_read_block_groups(struct btrfs_fs_info *info)
{
struct btrfs_path *path;
int ret;
struct btrfs_block_group_cache *cache;
struct btrfs_space_info *space_info;
struct btrfs_key key;
struct btrfs_key found_key;
struct extent_buffer *leaf;
int need_clear = 0;
u64 cache_gen;
u64 feature;
int mixed;
feature = btrfs_super_incompat_flags(info->super_copy);
mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
key.objectid = 0;
key.offset = 0;
key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = READA_FORWARD;
cache_gen = btrfs_super_cache_generation(info->super_copy);
if (btrfs_test_opt(info, SPACE_CACHE) &&
btrfs_super_generation(info->super_copy) != cache_gen)
need_clear = 1;
if (btrfs_test_opt(info, CLEAR_CACHE))
need_clear = 1;
while (1) {
ret = find_first_block_group(info, path, &key);
if (ret > 0)
break;
if (ret != 0)
goto error;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
cache = btrfs_create_block_group_cache(info, found_key.objectid,
found_key.offset);
if (!cache) {
ret = -ENOMEM;
goto error;
}
if (need_clear) {
/*
* When we mount with old space cache, we need to
* set BTRFS_DC_CLEAR and set dirty flag.
*
* a) Setting 'BTRFS_DC_CLEAR' makes sure that we
* truncate the old free space cache inode and
* setup a new one.
* b) Setting 'dirty flag' makes sure that we flush
* the new space cache info onto disk.
*/
if (btrfs_test_opt(info, SPACE_CACHE))
cache->disk_cache_state = BTRFS_DC_CLEAR;
}
read_extent_buffer(leaf, &cache->item,
btrfs_item_ptr_offset(leaf, path->slots[0]),
sizeof(cache->item));
cache->flags = btrfs_block_group_flags(&cache->item);
if (!mixed &&
((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
(cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
btrfs_err(info,
"bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
cache->key.objectid);
ret = -EINVAL;
goto error;
}
key.objectid = found_key.objectid + found_key.offset;
btrfs_release_path(path);
/*
* We need to exclude the super stripes now so that the space
* info has super bytes accounted for, otherwise we'll think
* we have more space than we actually do.
*/
ret = exclude_super_stripes(cache);
if (ret) {
/*
* We may have excluded something, so call this just in
* case.
*/
btrfs_free_excluded_extents(cache);
btrfs_put_block_group(cache);
goto error;
}
/*
* check for two cases, either we are full, and therefore
* don't need to bother with the caching work since we won't
* find any space, or we are empty, and we can just add all
* the space in and be done with it. This saves us _a_lot_ of
* time, particularly in the full case.
*/
if (found_key.offset == btrfs_block_group_used(&cache->item)) {
cache->last_byte_to_unpin = (u64)-1;
cache->cached = BTRFS_CACHE_FINISHED;
btrfs_free_excluded_extents(cache);
} else if (btrfs_block_group_used(&cache->item) == 0) {
cache->last_byte_to_unpin = (u64)-1;
cache->cached = BTRFS_CACHE_FINISHED;
add_new_free_space(cache, found_key.objectid,
found_key.objectid +
found_key.offset);
btrfs_free_excluded_extents(cache);
}
ret = btrfs_add_block_group_cache(info, cache);
if (ret) {
btrfs_remove_free_space_cache(cache);
btrfs_put_block_group(cache);
goto error;
}
trace_btrfs_add_block_group(info, cache, 0);
btrfs_update_space_info(info, cache->flags, found_key.offset,
btrfs_block_group_used(&cache->item),
cache->bytes_super, &space_info);
cache->space_info = space_info;
link_block_group(cache);
set_avail_alloc_bits(info, cache->flags);
if (btrfs_chunk_readonly(info, cache->key.objectid)) {
inc_block_group_ro(cache, 1);
} else if (btrfs_block_group_used(&cache->item) == 0) {
ASSERT(list_empty(&cache->bg_list));
btrfs_mark_bg_unused(cache);
}
}
list_for_each_entry_rcu(space_info, &info->space_info, list) {
if (!(get_alloc_profile(info, space_info->flags) &
(BTRFS_BLOCK_GROUP_RAID10 |
BTRFS_BLOCK_GROUP_RAID1_MASK |
BTRFS_BLOCK_GROUP_RAID56_MASK |
BTRFS_BLOCK_GROUP_DUP)))
continue;
/*
* avoid allocating from un-mirrored block group if there are
* mirrored block groups.
*/
list_for_each_entry(cache,
&space_info->block_groups[BTRFS_RAID_RAID0],
list)
inc_block_group_ro(cache, 1);
list_for_each_entry(cache,
&space_info->block_groups[BTRFS_RAID_SINGLE],
list)
inc_block_group_ro(cache, 1);
}
btrfs_init_global_block_rsv(info);
ret = check_chunk_block_group_mappings(info);
error:
btrfs_free_path(path);
return ret;
}
void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *block_group;
struct btrfs_root *extent_root = fs_info->extent_root;
struct btrfs_block_group_item item;
struct btrfs_key key;
int ret = 0;
if (!trans->can_flush_pending_bgs)
return;
while (!list_empty(&trans->new_bgs)) {
block_group = list_first_entry(&trans->new_bgs,
struct btrfs_block_group_cache,
bg_list);
if (ret)
goto next;
spin_lock(&block_group->lock);
memcpy(&item, &block_group->item, sizeof(item));
memcpy(&key, &block_group->key, sizeof(key));
spin_unlock(&block_group->lock);
ret = btrfs_insert_item(trans, extent_root, &key, &item,
sizeof(item));
if (ret)
btrfs_abort_transaction(trans, ret);
ret = btrfs_finish_chunk_alloc(trans, key.objectid, key.offset);
if (ret)
btrfs_abort_transaction(trans, ret);
add_block_group_free_space(trans, block_group);
/* already aborted the transaction if it failed. */
next:
btrfs_delayed_refs_rsv_release(fs_info, 1);
list_del_init(&block_group->bg_list);
}
btrfs_trans_release_chunk_metadata(trans);
}
int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
u64 type, u64 chunk_offset, u64 size)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group_cache *cache;
int ret;
btrfs_set_log_full_commit(trans);
cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
if (!cache)
return -ENOMEM;
btrfs_set_block_group_used(&cache->item, bytes_used);
btrfs_set_block_group_chunk_objectid(&cache->item,
BTRFS_FIRST_CHUNK_TREE_OBJECTID);
btrfs_set_block_group_flags(&cache->item, type);
cache->flags = type;
cache->last_byte_to_unpin = (u64)-1;
cache->cached = BTRFS_CACHE_FINISHED;
cache->needs_free_space = 1;
ret = exclude_super_stripes(cache);
if (ret) {
/*
* We may have excluded something, so call this just in
* case.
*/
btrfs_free_excluded_extents(cache);
btrfs_put_block_group(cache);
return ret;
}
add_new_free_space(cache, chunk_offset, chunk_offset + size);
btrfs_free_excluded_extents(cache);
#ifdef CONFIG_BTRFS_DEBUG
if (btrfs_should_fragment_free_space(cache)) {
u64 new_bytes_used = size - bytes_used;
bytes_used += new_bytes_used >> 1;
btrfs_fragment_free_space(cache);
}
#endif
/*
* Ensure the corresponding space_info object is created and
* assigned to our block group. We want our bg to be added to the rbtree
* with its ->space_info set.
*/
cache->space_info = btrfs_find_space_info(fs_info, cache->flags);
ASSERT(cache->space_info);
ret = btrfs_add_block_group_cache(fs_info, cache);
if (ret) {
btrfs_remove_free_space_cache(cache);
btrfs_put_block_group(cache);
return ret;
}
/*
* Now that our block group has its ->space_info set and is inserted in
* the rbtree, update the space info's counters.
*/
trace_btrfs_add_block_group(fs_info, cache, 1);
btrfs_update_space_info(fs_info, cache->flags, size, bytes_used,
cache->bytes_super, &cache->space_info);
btrfs_update_global_block_rsv(fs_info);
link_block_group(cache);
list_add_tail(&cache->bg_list, &trans->new_bgs);
trans->delayed_ref_updates++;
btrfs_update_delayed_refs_rsv(trans);
set_avail_alloc_bits(fs_info, type);
return 0;
}
static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
{
u64 extra_flags = chunk_to_extended(flags) &
BTRFS_EXTENDED_PROFILE_MASK;
write_seqlock(&fs_info->profiles_lock);
if (flags & BTRFS_BLOCK_GROUP_DATA)
fs_info->avail_data_alloc_bits &= ~extra_flags;
if (flags & BTRFS_BLOCK_GROUP_METADATA)
fs_info->avail_metadata_alloc_bits &= ~extra_flags;
if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
fs_info->avail_system_alloc_bits &= ~extra_flags;
write_sequnlock(&fs_info->profiles_lock);
}
/*
* Clear incompat bits for the following feature(s):
*
* - RAID56 - in case there's neither RAID5 nor RAID6 profile block group
* in the whole filesystem
*/
static void clear_incompat_bg_bits(struct btrfs_fs_info *fs_info, u64 flags)
{
if (flags & BTRFS_BLOCK_GROUP_RAID56_MASK) {
struct list_head *head = &fs_info->space_info;
struct btrfs_space_info *sinfo;
list_for_each_entry_rcu(sinfo, head, list) {
bool found = false;
down_read(&sinfo->groups_sem);
if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID5]))
found = true;
if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID6]))
found = true;
up_read(&sinfo->groups_sem);
if (found)
return;
}
btrfs_clear_fs_incompat(fs_info, RAID56);
}
}
int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
u64 group_start, struct extent_map *em)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root = fs_info->extent_root;
struct btrfs_path *path;
struct btrfs_block_group_cache *block_group;
struct btrfs_free_cluster *cluster;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_key key;
struct inode *inode;
struct kobject *kobj = NULL;
int ret;
int index;
int factor;
struct btrfs_caching_control *caching_ctl = NULL;
bool remove_em;
bool remove_rsv = false;
block_group = btrfs_lookup_block_group(fs_info, group_start);
BUG_ON(!block_group);
BUG_ON(!block_group->ro);
trace_btrfs_remove_block_group(block_group);
/*
* Free the reserved super bytes from this block group before
* remove it.
*/
btrfs_free_excluded_extents(block_group);
btrfs_free_ref_tree_range(fs_info, block_group->key.objectid,
block_group->key.offset);
memcpy(&key, &block_group->key, sizeof(key));
index = btrfs_bg_flags_to_raid_index(block_group->flags);
factor = btrfs_bg_type_to_factor(block_group->flags);
/* make sure this block group isn't part of an allocation cluster */
cluster = &fs_info->data_alloc_cluster;
spin_lock(&cluster->refill_lock);
btrfs_return_cluster_to_free_space(block_group, cluster);
spin_unlock(&cluster->refill_lock);
/*
* make sure this block group isn't part of a metadata
* allocation cluster
*/
cluster = &fs_info->meta_alloc_cluster;
spin_lock(&cluster->refill_lock);
btrfs_return_cluster_to_free_space(block_group, cluster);
spin_unlock(&cluster->refill_lock);
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
/*
* get the inode first so any iput calls done for the io_list
* aren't the final iput (no unlinks allowed now)
*/
inode = lookup_free_space_inode(block_group, path);
mutex_lock(&trans->transaction->cache_write_mutex);
/*
* Make sure our free space cache IO is done before removing the
* free space inode
*/
spin_lock(&trans->transaction->dirty_bgs_lock);
if (!list_empty(&block_group->io_list)) {
list_del_init(&block_group->io_list);
WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
spin_unlock(&trans->transaction->dirty_bgs_lock);
btrfs_wait_cache_io(trans, block_group, path);
btrfs_put_block_group(block_group);
spin_lock(&trans->transaction->dirty_bgs_lock);
}
if (!list_empty(&block_group->dirty_list)) {
list_del_init(&block_group->dirty_list);
remove_rsv = true;
btrfs_put_block_group(block_group);
}
spin_unlock(&trans->transaction->dirty_bgs_lock);
mutex_unlock(&trans->transaction->cache_write_mutex);
if (!IS_ERR(inode)) {
ret = btrfs_orphan_add(trans, BTRFS_I(inode));
if (ret) {
btrfs_add_delayed_iput(inode);
goto out;
}
clear_nlink(inode);
/* One for the block groups ref */
spin_lock(&block_group->lock);
if (block_group->iref) {
block_group->iref = 0;
block_group->inode = NULL;
spin_unlock(&block_group->lock);
iput(inode);
} else {
spin_unlock(&block_group->lock);
}
/* One for our lookup ref */
btrfs_add_delayed_iput(inode);
}
key.objectid = BTRFS_FREE_SPACE_OBJECTID;
key.offset = block_group->key.objectid;
key.type = 0;
ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
if (ret < 0)
goto out;
if (ret > 0)
btrfs_release_path(path);
if (ret == 0) {
ret = btrfs_del_item(trans, tree_root, path);
if (ret)
goto out;
btrfs_release_path(path);
}
spin_lock(&fs_info->block_group_cache_lock);
rb_erase(&block_group->cache_node,
&fs_info->block_group_cache_tree);
RB_CLEAR_NODE(&block_group->cache_node);
if (fs_info->first_logical_byte == block_group->key.objectid)
fs_info->first_logical_byte = (u64)-1;
spin_unlock(&fs_info->block_group_cache_lock);
down_write(&block_group->space_info->groups_sem);
/*
* we must use list_del_init so people can check to see if they
* are still on the list after taking the semaphore
*/
list_del_init(&block_group->list);
if (list_empty(&block_group->space_info->block_groups[index])) {
kobj = block_group->space_info->block_group_kobjs[index];
block_group->space_info->block_group_kobjs[index] = NULL;
clear_avail_alloc_bits(fs_info, block_group->flags);
}
up_write(&block_group->space_info->groups_sem);
clear_incompat_bg_bits(fs_info, block_group->flags);
if (kobj) {
kobject_del(kobj);
kobject_put(kobj);
}
if (block_group->has_caching_ctl)
caching_ctl = btrfs_get_caching_control(block_group);
if (block_group->cached == BTRFS_CACHE_STARTED)
btrfs_wait_block_group_cache_done(block_group);
if (block_group->has_caching_ctl) {
down_write(&fs_info->commit_root_sem);
if (!caching_ctl) {
struct btrfs_caching_control *ctl;
list_for_each_entry(ctl,
&fs_info->caching_block_groups, list)
if (ctl->block_group == block_group) {
caching_ctl = ctl;
refcount_inc(&caching_ctl->count);
break;
}
}
if (caching_ctl)
list_del_init(&caching_ctl->list);
up_write(&fs_info->commit_root_sem);
if (caching_ctl) {
/* Once for the caching bgs list and once for us. */
btrfs_put_caching_control(caching_ctl);
btrfs_put_caching_control(caching_ctl);
}
}
spin_lock(&trans->transaction->dirty_bgs_lock);
WARN_ON(!list_empty(&block_group->dirty_list));
WARN_ON(!list_empty(&block_group->io_list));
spin_unlock(&trans->transaction->dirty_bgs_lock);
btrfs_remove_free_space_cache(block_group);
spin_lock(&block_group->space_info->lock);
list_del_init(&block_group->ro_list);
if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
WARN_ON(block_group->space_info->total_bytes
< block_group->key.offset);
WARN_ON(block_group->space_info->bytes_readonly
< block_group->key.offset);
WARN_ON(block_group->space_info->disk_total
< block_group->key.offset * factor);
}
block_group->space_info->total_bytes -= block_group->key.offset;
block_group->space_info->bytes_readonly -= block_group->key.offset;
block_group->space_info->disk_total -= block_group->key.offset * factor;
spin_unlock(&block_group->space_info->lock);
memcpy(&key, &block_group->key, sizeof(key));
mutex_lock(&fs_info->chunk_mutex);
spin_lock(&block_group->lock);
block_group->removed = 1;
/*
* At this point trimming can't start on this block group, because we
* removed the block group from the tree fs_info->block_group_cache_tree
* so no one can't find it anymore and even if someone already got this
* block group before we removed it from the rbtree, they have already
* incremented block_group->trimming - if they didn't, they won't find
* any free space entries because we already removed them all when we
* called btrfs_remove_free_space_cache().
*
* And we must not remove the extent map from the fs_info->mapping_tree
* to prevent the same logical address range and physical device space
* ranges from being reused for a new block group. This is because our
* fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
* completely transactionless, so while it is trimming a range the
* currently running transaction might finish and a new one start,
* allowing for new block groups to be created that can reuse the same
* physical device locations unless we take this special care.
*
* There may also be an implicit trim operation if the file system
* is mounted with -odiscard. The same protections must remain
* in place until the extents have been discarded completely when
* the transaction commit has completed.
*/
remove_em = (atomic_read(&block_group->trimming) == 0);
spin_unlock(&block_group->lock);
mutex_unlock(&fs_info->chunk_mutex);
ret = remove_block_group_free_space(trans, block_group);
if (ret)
goto out;
btrfs_put_block_group(block_group);
btrfs_put_block_group(block_group);
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0)
ret = -EIO;
if (ret < 0)
goto out;
ret = btrfs_del_item(trans, root, path);
if (ret)
goto out;
if (remove_em) {
struct extent_map_tree *em_tree;
em_tree = &fs_info->mapping_tree;
write_lock(&em_tree->lock);
remove_extent_mapping(em_tree, em);
write_unlock(&em_tree->lock);
/* once for the tree */
free_extent_map(em);
}
out:
if (remove_rsv)
btrfs_delayed_refs_rsv_release(fs_info, 1);
btrfs_free_path(path);
return ret;
}
struct btrfs_trans_handle *
btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
const u64 chunk_offset)
{
struct extent_map_tree *em_tree = &fs_info->mapping_tree;
struct extent_map *em;
struct map_lookup *map;
unsigned int num_items;
read_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, chunk_offset, 1);
read_unlock(&em_tree->lock);
ASSERT(em && em->start == chunk_offset);
/*
* We need to reserve 3 + N units from the metadata space info in order
* to remove a block group (done at btrfs_remove_chunk() and at
* btrfs_remove_block_group()), which are used for:
*
* 1 unit for adding the free space inode's orphan (located in the tree
* of tree roots).
* 1 unit for deleting the block group item (located in the extent
* tree).
* 1 unit for deleting the free space item (located in tree of tree
* roots).
* N units for deleting N device extent items corresponding to each
* stripe (located in the device tree).
*
* In order to remove a block group we also need to reserve units in the
* system space info in order to update the chunk tree (update one or
* more device items and remove one chunk item), but this is done at
* btrfs_remove_chunk() through a call to check_system_chunk().
*/
map = em->map_lookup;
num_items = 3 + map->num_stripes;
free_extent_map(em);
return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
num_items, 1);
}
/*
* Process the unused_bgs list and remove any that don't have any allocated
* space inside of them.
*/
void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
{
struct btrfs_block_group_cache *block_group;
struct btrfs_space_info *space_info;
struct btrfs_trans_handle *trans;
int ret = 0;
if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
return;
spin_lock(&fs_info->unused_bgs_lock);
while (!list_empty(&fs_info->unused_bgs)) {
u64 start, end;
int trimming;
block_group = list_first_entry(&fs_info->unused_bgs,
struct btrfs_block_group_cache,
bg_list);
list_del_init(&block_group->bg_list);
space_info = block_group->space_info;
if (ret || btrfs_mixed_space_info(space_info)) {
btrfs_put_block_group(block_group);
continue;
}
spin_unlock(&fs_info->unused_bgs_lock);
mutex_lock(&fs_info->delete_unused_bgs_mutex);
/* Don't want to race with allocators so take the groups_sem */
down_write(&space_info->groups_sem);
spin_lock(&block_group->lock);
if (block_group->reserved || block_group->pinned ||
btrfs_block_group_used(&block_group->item) ||
block_group->ro ||
list_is_singular(&block_group->list)) {
/*
* We want to bail if we made new allocations or have
* outstanding allocations in this block group. We do
* the ro check in case balance is currently acting on
* this block group.
*/
trace_btrfs_skip_unused_block_group(block_group);
spin_unlock(&block_group->lock);
up_write(&space_info->groups_sem);
goto next;
}
spin_unlock(&block_group->lock);
/* We don't want to force the issue, only flip if it's ok. */
ret = inc_block_group_ro(block_group, 0);
up_write(&space_info->groups_sem);
if (ret < 0) {
ret = 0;
goto next;
}
/*
* Want to do this before we do anything else so we can recover
* properly if we fail to join the transaction.
*/
trans = btrfs_start_trans_remove_block_group(fs_info,
block_group->key.objectid);
if (IS_ERR(trans)) {
btrfs_dec_block_group_ro(block_group);
ret = PTR_ERR(trans);
goto next;
}
/*
* We could have pending pinned extents for this block group,
* just delete them, we don't care about them anymore.
*/
start = block_group->key.objectid;
end = start + block_group->key.offset - 1;
/*
* Hold the unused_bg_unpin_mutex lock to avoid racing with
* btrfs_finish_extent_commit(). If we are at transaction N,
* another task might be running finish_extent_commit() for the
* previous transaction N - 1, and have seen a range belonging
* to the block group in freed_extents[] before we were able to
* clear the whole block group range from freed_extents[]. This
* means that task can lookup for the block group after we
* unpinned it from freed_extents[] and removed it, leading to
* a BUG_ON() at btrfs_unpin_extent_range().
*/
mutex_lock(&fs_info->unused_bg_unpin_mutex);
ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
EXTENT_DIRTY);
if (ret) {
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
btrfs_dec_block_group_ro(block_group);
goto end_trans;
}
ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
EXTENT_DIRTY);
if (ret) {
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
btrfs_dec_block_group_ro(block_group);
goto end_trans;
}
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
/* Reset pinned so btrfs_put_block_group doesn't complain */
spin_lock(&space_info->lock);
spin_lock(&block_group->lock);
btrfs_space_info_update_bytes_pinned(fs_info, space_info,
-block_group->pinned);
space_info->bytes_readonly += block_group->pinned;
percpu_counter_add_batch(&space_info->total_bytes_pinned,
-block_group->pinned,
BTRFS_TOTAL_BYTES_PINNED_BATCH);
block_group->pinned = 0;
spin_unlock(&block_group->lock);
spin_unlock(&space_info->lock);
/* DISCARD can flip during remount */
trimming = btrfs_test_opt(fs_info, DISCARD);
/* Implicit trim during transaction commit. */
if (trimming)
btrfs_get_block_group_trimming(block_group);
/*
* Btrfs_remove_chunk will abort the transaction if things go
* horribly wrong.
*/
ret = btrfs_remove_chunk(trans, block_group->key.objectid);
if (ret) {
if (trimming)
btrfs_put_block_group_trimming(block_group);
goto end_trans;
}
/*
* If we're not mounted with -odiscard, we can just forget
* about this block group. Otherwise we'll need to wait
* until transaction commit to do the actual discard.
*/
if (trimming) {
spin_lock(&fs_info->unused_bgs_lock);
/*
* A concurrent scrub might have added us to the list
* fs_info->unused_bgs, so use a list_move operation
* to add the block group to the deleted_bgs list.
*/
list_move(&block_group->bg_list,
&trans->transaction->deleted_bgs);
spin_unlock(&fs_info->unused_bgs_lock);
btrfs_get_block_group(block_group);
}
end_trans:
btrfs_end_transaction(trans);
next:
mutex_unlock(&fs_info->delete_unused_bgs_mutex);
btrfs_put_block_group(block_group);
spin_lock(&fs_info->unused_bgs_lock);
}
spin_unlock(&fs_info->unused_bgs_lock);
}
int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
u64 start, u64 end)
{
return unpin_extent_range(fs_info, start, end, false);
}
/*
* It used to be that old block groups would be left around forever.
* Iterating over them would be enough to trim unused space. Since we
* now automatically remove them, we also need to iterate over unallocated
* space.
*
* We don't want a transaction for this since the discard may take a
* substantial amount of time. We don't require that a transaction be
* running, but we do need to take a running transaction into account
* to ensure that we're not discarding chunks that were released or
* allocated in the current transaction.
*
* Holding the chunks lock will prevent other threads from allocating
* or releasing chunks, but it won't prevent a running transaction
* from committing and releasing the memory that the pending chunks
* list head uses. For that, we need to take a reference to the
* transaction and hold the commit root sem. We only need to hold
* it while performing the free space search since we have already
* held back allocations.
*/
static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)
{
u64 start = SZ_1M, len = 0, end = 0;
int ret;
*trimmed = 0;
/* Discard not supported = nothing to do. */
if (!blk_queue_discard(bdev_get_queue(device->bdev)))
return 0;
/* Not writable = nothing to do. */
if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
return 0;
/* No free space = nothing to do. */
if (device->total_bytes <= device->bytes_used)
return 0;
ret = 0;
while (1) {
struct btrfs_fs_info *fs_info = device->fs_info;
u64 bytes;
ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
if (ret)
break;
find_first_clear_extent_bit(&device->alloc_state, start,
&start, &end,
CHUNK_TRIMMED | CHUNK_ALLOCATED);
/* Ensure we skip the reserved area in the first 1M */
start = max_t(u64, start, SZ_1M);
/*
* If find_first_clear_extent_bit find a range that spans the
* end of the device it will set end to -1, in this case it's up
* to the caller to trim the value to the size of the device.
*/
end = min(end, device->total_bytes - 1);
len = end - start + 1;
/* We didn't find any extents */
if (!len) {
mutex_unlock(&fs_info->chunk_mutex);
ret = 0;
break;
}
ret = btrfs_issue_discard(device->bdev, start, len,
&bytes);
if (!ret)
set_extent_bits(&device->alloc_state, start,
start + bytes - 1,
CHUNK_TRIMMED);
mutex_unlock(&fs_info->chunk_mutex);
if (ret)
break;
start += len;
*trimmed += bytes;
if (fatal_signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
cond_resched();
}
return ret;
}
/*
* Trim the whole filesystem by:
* 1) trimming the free space in each block group
* 2) trimming the unallocated space on each device
*
* This will also continue trimming even if a block group or device encounters
* an error. The return value will be the last error, or 0 if nothing bad
* happens.
*/
int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
{
struct btrfs_block_group_cache *cache = NULL;
struct btrfs_device *device;
struct list_head *devices;
u64 group_trimmed;
u64 range_end = U64_MAX;
u64 start;
u64 end;
u64 trimmed = 0;
u64 bg_failed = 0;
u64 dev_failed = 0;
int bg_ret = 0;
int dev_ret = 0;
int ret = 0;
/*
* Check range overflow if range->len is set.
* The default range->len is U64_MAX.
*/
if (range->len != U64_MAX &&
check_add_overflow(range->start, range->len, &range_end))
return -EINVAL;
cache = btrfs_lookup_first_block_group(fs_info, range->start);
for (; cache; cache = btrfs_next_block_group(cache)) {
if (cache->key.objectid >= range_end) {
btrfs_put_block_group(cache);
break;
}
start = max(range->start, cache->key.objectid);
end = min(range_end, cache->key.objectid + cache->key.offset);
if (end - start >= range->minlen) {
if (!btrfs_block_group_cache_done(cache)) {
ret = btrfs_cache_block_group(cache, 0);
if (ret) {
bg_failed++;
bg_ret = ret;
continue;
}
ret = btrfs_wait_block_group_cache_done(cache);
if (ret) {
bg_failed++;
bg_ret = ret;
continue;
}
}
ret = btrfs_trim_block_group(cache,
&group_trimmed,
start,
end,
range->minlen);
trimmed += group_trimmed;
if (ret) {
bg_failed++;
bg_ret = ret;
continue;
}
}
}
if (bg_failed)
btrfs_warn(fs_info,
"failed to trim %llu block group(s), last error %d",
bg_failed, bg_ret);
mutex_lock(&fs_info->fs_devices->device_list_mutex);
devices = &fs_info->fs_devices->devices;
list_for_each_entry(device, devices, dev_list) {
ret = btrfs_trim_free_extents(device, &group_trimmed);
if (ret) {
dev_failed++;
dev_ret = ret;
break;
}
trimmed += group_trimmed;
}
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
if (dev_failed)
btrfs_warn(fs_info,
"failed to trim %llu device(s), last error %d",
dev_failed, dev_ret);
range->len = trimmed;
if (bg_ret)
return bg_ret;
return dev_ret;
}
/*
* btrfs_{start,end}_write_no_snapshotting() are similar to
* mnt_{want,drop}_write(), they are used to prevent some tasks from writing
* data into the page cache through nocow before the subvolume is snapshoted,
* but flush the data into disk after the snapshot creation, or to prevent
* operations while snapshotting is ongoing and that cause the snapshot to be
* inconsistent (writes followed by expanding truncates for example).
*/
void btrfs_end_write_no_snapshotting(struct btrfs_root *root)
{
percpu_counter_dec(&root->subv_writers->counter);
cond_wake_up(&root->subv_writers->wait);
}
int btrfs_start_write_no_snapshotting(struct btrfs_root *root)
{
if (atomic_read(&root->will_be_snapshotted))
return 0;
percpu_counter_inc(&root->subv_writers->counter);
/*
* Make sure counter is updated before we check for snapshot creation.
*/
smp_mb();
if (atomic_read(&root->will_be_snapshotted)) {
btrfs_end_write_no_snapshotting(root);
return 0;
}
return 1;
}
void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
{
while (true) {
int ret;
ret = btrfs_start_write_no_snapshotting(root);
if (ret)
break;
wait_var_event(&root->will_be_snapshotted,
!atomic_read(&root->will_be_snapshotted));
}
}
void btrfs_mark_bg_unused(struct btrfs_block_group_cache *bg)
{
struct btrfs_fs_info *fs_info = bg->fs_info;
spin_lock(&fs_info->unused_bgs_lock);
if (list_empty(&bg->bg_list)) {
btrfs_get_block_group(bg);
trace_btrfs_add_unused_block_group(bg);
list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
}
spin_unlock(&fs_info->unused_bgs_lock);
}
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