linux/fs/btrfs/block-rsv.c
Josef Bacik c18e323564 btrfs: reserve extra space for the free space tree
Filipe reported a problem where sometimes he'd get an ENOSPC abort when
running delayed refs with generic/619 and the free space tree enabled.
This is partly because we do not reserve space for modifying the free
space tree, nor do we have a block rsv associated with that tree.

The delayed_refs_rsv tracks the amount of space required to run delayed
refs.  This means 1 modification means 1 change to the extent root.
With the free space tree this turns into 2 changes, because modifying 1
extent means updating the extent tree and potentially updating the free
space tree to either remove that entry or add the free space.  Thus if
we have the FST enabled, simply double the reservation size for our
modification.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-01-07 14:18:25 +01:00

559 lines
17 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include "misc.h"
#include "ctree.h"
#include "block-rsv.h"
#include "space-info.h"
#include "transaction.h"
#include "block-group.h"
#include "disk-io.h"
/*
* HOW DO BLOCK RESERVES WORK
*
* Think of block_rsv's as buckets for logically grouped metadata
* reservations. Each block_rsv has a ->size and a ->reserved. ->size is
* how large we want our block rsv to be, ->reserved is how much space is
* currently reserved for this block reserve.
*
* ->failfast exists for the truncate case, and is described below.
*
* NORMAL OPERATION
*
* -> Reserve
* Entrance: btrfs_block_rsv_add, btrfs_block_rsv_refill
*
* We call into btrfs_reserve_metadata_bytes() with our bytes, which is
* accounted for in space_info->bytes_may_use, and then add the bytes to
* ->reserved, and ->size in the case of btrfs_block_rsv_add.
*
* ->size is an over-estimation of how much we may use for a particular
* operation.
*
* -> Use
* Entrance: btrfs_use_block_rsv
*
* When we do a btrfs_alloc_tree_block() we call into btrfs_use_block_rsv()
* to determine the appropriate block_rsv to use, and then verify that
* ->reserved has enough space for our tree block allocation. Once
* successful we subtract fs_info->nodesize from ->reserved.
*
* -> Finish
* Entrance: btrfs_block_rsv_release
*
* We are finished with our operation, subtract our individual reservation
* from ->size, and then subtract ->size from ->reserved and free up the
* excess if there is any.
*
* There is some logic here to refill the delayed refs rsv or the global rsv
* as needed, otherwise the excess is subtracted from
* space_info->bytes_may_use.
*
* TYPES OF BLOCK RESERVES
*
* BLOCK_RSV_TRANS, BLOCK_RSV_DELOPS, BLOCK_RSV_CHUNK
* These behave normally, as described above, just within the confines of the
* lifetime of their particular operation (transaction for the whole trans
* handle lifetime, for example).
*
* BLOCK_RSV_GLOBAL
* It is impossible to properly account for all the space that may be required
* to make our extent tree updates. This block reserve acts as an overflow
* buffer in case our delayed refs reserve does not reserve enough space to
* update the extent tree.
*
* We can steal from this in some cases as well, notably on evict() or
* truncate() in order to help users recover from ENOSPC conditions.
*
* BLOCK_RSV_DELALLOC
* The individual item sizes are determined by the per-inode size
* calculations, which are described with the delalloc code. This is pretty
* straightforward, it's just the calculation of ->size encodes a lot of
* different items, and thus it gets used when updating inodes, inserting file
* extents, and inserting checksums.
*
* BLOCK_RSV_DELREFS
* We keep a running tally of how many delayed refs we have on the system.
* We assume each one of these delayed refs are going to use a full
* reservation. We use the transaction items and pre-reserve space for every
* operation, and use this reservation to refill any gap between ->size and
* ->reserved that may exist.
*
* From there it's straightforward, removing a delayed ref means we remove its
* count from ->size and free up reservations as necessary. Since this is
* the most dynamic block reserve in the system, we will try to refill this
* block reserve first with any excess returned by any other block reserve.
*
* BLOCK_RSV_EMPTY
* This is the fallback block reserve to make us try to reserve space if we
* don't have a specific bucket for this allocation. It is mostly used for
* updating the device tree and such, since that is a separate pool we're
* content to just reserve space from the space_info on demand.
*
* BLOCK_RSV_TEMP
* This is used by things like truncate and iput. We will temporarily
* allocate a block reserve, set it to some size, and then truncate bytes
* until we have no space left. With ->failfast set we'll simply return
* ENOSPC from btrfs_use_block_rsv() to signal that we need to unwind and try
* to make a new reservation. This is because these operations are
* unbounded, so we want to do as much work as we can, and then back off and
* re-reserve.
*/
static u64 block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
struct btrfs_block_rsv *block_rsv,
struct btrfs_block_rsv *dest, u64 num_bytes,
u64 *qgroup_to_release_ret)
{
struct btrfs_space_info *space_info = block_rsv->space_info;
u64 qgroup_to_release = 0;
u64 ret;
spin_lock(&block_rsv->lock);
if (num_bytes == (u64)-1) {
num_bytes = block_rsv->size;
qgroup_to_release = block_rsv->qgroup_rsv_size;
}
block_rsv->size -= num_bytes;
if (block_rsv->reserved >= block_rsv->size) {
num_bytes = block_rsv->reserved - block_rsv->size;
block_rsv->reserved = block_rsv->size;
block_rsv->full = 1;
} else {
num_bytes = 0;
}
if (block_rsv->qgroup_rsv_reserved >= block_rsv->qgroup_rsv_size) {
qgroup_to_release = block_rsv->qgroup_rsv_reserved -
block_rsv->qgroup_rsv_size;
block_rsv->qgroup_rsv_reserved = block_rsv->qgroup_rsv_size;
} else {
qgroup_to_release = 0;
}
spin_unlock(&block_rsv->lock);
ret = num_bytes;
if (num_bytes > 0) {
if (dest) {
spin_lock(&dest->lock);
if (!dest->full) {
u64 bytes_to_add;
bytes_to_add = dest->size - dest->reserved;
bytes_to_add = min(num_bytes, bytes_to_add);
dest->reserved += bytes_to_add;
if (dest->reserved >= dest->size)
dest->full = 1;
num_bytes -= bytes_to_add;
}
spin_unlock(&dest->lock);
}
if (num_bytes)
btrfs_space_info_free_bytes_may_use(fs_info,
space_info,
num_bytes);
}
if (qgroup_to_release_ret)
*qgroup_to_release_ret = qgroup_to_release;
return ret;
}
int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
struct btrfs_block_rsv *dst, u64 num_bytes,
bool update_size)
{
int ret;
ret = btrfs_block_rsv_use_bytes(src, num_bytes);
if (ret)
return ret;
btrfs_block_rsv_add_bytes(dst, num_bytes, update_size);
return 0;
}
void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
{
memset(rsv, 0, sizeof(*rsv));
spin_lock_init(&rsv->lock);
rsv->type = type;
}
void btrfs_init_metadata_block_rsv(struct btrfs_fs_info *fs_info,
struct btrfs_block_rsv *rsv,
unsigned short type)
{
btrfs_init_block_rsv(rsv, type);
rsv->space_info = btrfs_find_space_info(fs_info,
BTRFS_BLOCK_GROUP_METADATA);
}
struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info,
unsigned short type)
{
struct btrfs_block_rsv *block_rsv;
block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
if (!block_rsv)
return NULL;
btrfs_init_metadata_block_rsv(fs_info, block_rsv, type);
return block_rsv;
}
void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info,
struct btrfs_block_rsv *rsv)
{
if (!rsv)
return;
btrfs_block_rsv_release(fs_info, rsv, (u64)-1, NULL);
kfree(rsv);
}
int btrfs_block_rsv_add(struct btrfs_fs_info *fs_info,
struct btrfs_block_rsv *block_rsv, u64 num_bytes,
enum btrfs_reserve_flush_enum flush)
{
int ret;
if (num_bytes == 0)
return 0;
ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv, num_bytes, flush);
if (!ret)
btrfs_block_rsv_add_bytes(block_rsv, num_bytes, true);
return ret;
}
int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor)
{
u64 num_bytes = 0;
int ret = -ENOSPC;
if (!block_rsv)
return 0;
spin_lock(&block_rsv->lock);
num_bytes = div_factor(block_rsv->size, min_factor);
if (block_rsv->reserved >= num_bytes)
ret = 0;
spin_unlock(&block_rsv->lock);
return ret;
}
int btrfs_block_rsv_refill(struct btrfs_fs_info *fs_info,
struct btrfs_block_rsv *block_rsv, u64 min_reserved,
enum btrfs_reserve_flush_enum flush)
{
u64 num_bytes = 0;
int ret = -ENOSPC;
if (!block_rsv)
return 0;
spin_lock(&block_rsv->lock);
num_bytes = min_reserved;
if (block_rsv->reserved >= num_bytes)
ret = 0;
else
num_bytes -= block_rsv->reserved;
spin_unlock(&block_rsv->lock);
if (!ret)
return 0;
ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv, num_bytes, flush);
if (!ret) {
btrfs_block_rsv_add_bytes(block_rsv, num_bytes, false);
return 0;
}
return ret;
}
u64 btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
struct btrfs_block_rsv *block_rsv, u64 num_bytes,
u64 *qgroup_to_release)
{
struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
struct btrfs_block_rsv *target = NULL;
/*
* If we are the delayed_rsv then push to the global rsv, otherwise dump
* into the delayed rsv if it is not full.
*/
if (block_rsv == delayed_rsv)
target = global_rsv;
else if (block_rsv != global_rsv && !delayed_rsv->full)
target = delayed_rsv;
if (target && block_rsv->space_info != target->space_info)
target = NULL;
return block_rsv_release_bytes(fs_info, block_rsv, target, num_bytes,
qgroup_to_release);
}
int btrfs_block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv, u64 num_bytes)
{
int ret = -ENOSPC;
spin_lock(&block_rsv->lock);
if (block_rsv->reserved >= num_bytes) {
block_rsv->reserved -= num_bytes;
if (block_rsv->reserved < block_rsv->size)
block_rsv->full = 0;
ret = 0;
}
spin_unlock(&block_rsv->lock);
return ret;
}
void btrfs_block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
u64 num_bytes, bool update_size)
{
spin_lock(&block_rsv->lock);
block_rsv->reserved += num_bytes;
if (update_size)
block_rsv->size += num_bytes;
else if (block_rsv->reserved >= block_rsv->size)
block_rsv->full = 1;
spin_unlock(&block_rsv->lock);
}
int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
struct btrfs_block_rsv *dest, u64 num_bytes,
int min_factor)
{
struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
u64 min_bytes;
if (global_rsv->space_info != dest->space_info)
return -ENOSPC;
spin_lock(&global_rsv->lock);
min_bytes = div_factor(global_rsv->size, min_factor);
if (global_rsv->reserved < min_bytes + num_bytes) {
spin_unlock(&global_rsv->lock);
return -ENOSPC;
}
global_rsv->reserved -= num_bytes;
if (global_rsv->reserved < global_rsv->size)
global_rsv->full = 0;
spin_unlock(&global_rsv->lock);
btrfs_block_rsv_add_bytes(dest, num_bytes, true);
return 0;
}
void btrfs_update_global_block_rsv(struct btrfs_fs_info *fs_info)
{
struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
struct btrfs_space_info *sinfo = block_rsv->space_info;
struct btrfs_root *root, *tmp;
u64 num_bytes = btrfs_root_used(&fs_info->tree_root->root_item);
unsigned int min_items = 1;
/*
* The global block rsv is based on the size of the extent tree, the
* checksum tree and the root tree. If the fs is empty we want to set
* it to a minimal amount for safety.
*
* We also are going to need to modify the minimum of the tree root and
* any global roots we could touch.
*/
read_lock(&fs_info->global_root_lock);
rbtree_postorder_for_each_entry_safe(root, tmp, &fs_info->global_root_tree,
rb_node) {
if (root->root_key.objectid == BTRFS_EXTENT_TREE_OBJECTID ||
root->root_key.objectid == BTRFS_CSUM_TREE_OBJECTID ||
root->root_key.objectid == BTRFS_FREE_SPACE_TREE_OBJECTID) {
num_bytes += btrfs_root_used(&root->root_item);
min_items++;
}
}
read_unlock(&fs_info->global_root_lock);
/*
* But we also want to reserve enough space so we can do the fallback
* global reserve for an unlink, which is an additional 5 items (see the
* comment in __unlink_start_trans for what we're modifying.)
*
* But we also need space for the delayed ref updates from the unlink,
* so its 10, 5 for the actual operation, and 5 for the delayed ref
* updates.
*/
min_items += 10;
num_bytes = max_t(u64, num_bytes,
btrfs_calc_insert_metadata_size(fs_info, min_items));
spin_lock(&sinfo->lock);
spin_lock(&block_rsv->lock);
block_rsv->size = min_t(u64, num_bytes, SZ_512M);
if (block_rsv->reserved < block_rsv->size) {
num_bytes = block_rsv->size - block_rsv->reserved;
btrfs_space_info_update_bytes_may_use(fs_info, sinfo,
num_bytes);
block_rsv->reserved = block_rsv->size;
} else if (block_rsv->reserved > block_rsv->size) {
num_bytes = block_rsv->reserved - block_rsv->size;
btrfs_space_info_update_bytes_may_use(fs_info, sinfo,
-num_bytes);
block_rsv->reserved = block_rsv->size;
btrfs_try_granting_tickets(fs_info, sinfo);
}
if (block_rsv->reserved == block_rsv->size)
block_rsv->full = 1;
else
block_rsv->full = 0;
if (block_rsv->size >= sinfo->total_bytes)
sinfo->force_alloc = CHUNK_ALLOC_FORCE;
spin_unlock(&block_rsv->lock);
spin_unlock(&sinfo->lock);
}
void btrfs_init_root_block_rsv(struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
switch (root->root_key.objectid) {
case BTRFS_CSUM_TREE_OBJECTID:
case BTRFS_EXTENT_TREE_OBJECTID:
case BTRFS_FREE_SPACE_TREE_OBJECTID:
root->block_rsv = &fs_info->delayed_refs_rsv;
break;
case BTRFS_ROOT_TREE_OBJECTID:
case BTRFS_DEV_TREE_OBJECTID:
case BTRFS_QUOTA_TREE_OBJECTID:
root->block_rsv = &fs_info->global_block_rsv;
break;
case BTRFS_CHUNK_TREE_OBJECTID:
root->block_rsv = &fs_info->chunk_block_rsv;
break;
default:
root->block_rsv = NULL;
break;
}
}
void btrfs_init_global_block_rsv(struct btrfs_fs_info *fs_info)
{
struct btrfs_space_info *space_info;
space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
fs_info->chunk_block_rsv.space_info = space_info;
space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
fs_info->global_block_rsv.space_info = space_info;
fs_info->trans_block_rsv.space_info = space_info;
fs_info->empty_block_rsv.space_info = space_info;
fs_info->delayed_block_rsv.space_info = space_info;
fs_info->delayed_refs_rsv.space_info = space_info;
btrfs_update_global_block_rsv(fs_info);
}
void btrfs_release_global_block_rsv(struct btrfs_fs_info *fs_info)
{
btrfs_block_rsv_release(fs_info, &fs_info->global_block_rsv, (u64)-1,
NULL);
WARN_ON(fs_info->trans_block_rsv.size > 0);
WARN_ON(fs_info->trans_block_rsv.reserved > 0);
WARN_ON(fs_info->chunk_block_rsv.size > 0);
WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
WARN_ON(fs_info->delayed_block_rsv.size > 0);
WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
WARN_ON(fs_info->delayed_refs_rsv.reserved > 0);
WARN_ON(fs_info->delayed_refs_rsv.size > 0);
}
static struct btrfs_block_rsv *get_block_rsv(
const struct btrfs_trans_handle *trans,
const struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_block_rsv *block_rsv = NULL;
if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
(root == fs_info->uuid_root) ||
(trans->adding_csums &&
root->root_key.objectid == BTRFS_CSUM_TREE_OBJECTID))
block_rsv = trans->block_rsv;
if (!block_rsv)
block_rsv = root->block_rsv;
if (!block_rsv)
block_rsv = &fs_info->empty_block_rsv;
return block_rsv;
}
struct btrfs_block_rsv *btrfs_use_block_rsv(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u32 blocksize)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_block_rsv *block_rsv;
struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
int ret;
bool global_updated = false;
block_rsv = get_block_rsv(trans, root);
if (unlikely(block_rsv->size == 0))
goto try_reserve;
again:
ret = btrfs_block_rsv_use_bytes(block_rsv, blocksize);
if (!ret)
return block_rsv;
if (block_rsv->failfast)
return ERR_PTR(ret);
if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
global_updated = true;
btrfs_update_global_block_rsv(fs_info);
goto again;
}
/*
* The global reserve still exists to save us from ourselves, so don't
* warn_on if we are short on our delayed refs reserve.
*/
if (block_rsv->type != BTRFS_BLOCK_RSV_DELREFS &&
btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
static DEFINE_RATELIMIT_STATE(_rs,
DEFAULT_RATELIMIT_INTERVAL * 10,
/*DEFAULT_RATELIMIT_BURST*/ 1);
if (__ratelimit(&_rs))
WARN(1, KERN_DEBUG
"BTRFS: block rsv %d returned %d\n",
block_rsv->type, ret);
}
try_reserve:
ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv, blocksize,
BTRFS_RESERVE_NO_FLUSH);
if (!ret)
return block_rsv;
/*
* If we couldn't reserve metadata bytes try and use some from
* the global reserve if its space type is the same as the global
* reservation.
*/
if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
block_rsv->space_info == global_rsv->space_info) {
ret = btrfs_block_rsv_use_bytes(global_rsv, blocksize);
if (!ret)
return global_rsv;
}
return ERR_PTR(ret);
}