linux/fs/btrfs/inode-item.c
David Sterba ca283ea992 btrfs: constify more pointer parameters
Continue adding const to parameters.  This is for clarity and minor
addition to safety. There are some minor effects, in the assembly code
and .ko measured on release config.

Signed-off-by: David Sterba <dsterba@suse.com>
2024-09-10 16:51:22 +02:00

754 lines
20 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include "ctree.h"
#include "fs.h"
#include "messages.h"
#include "inode-item.h"
#include "disk-io.h"
#include "transaction.h"
#include "space-info.h"
#include "accessors.h"
#include "extent-tree.h"
#include "file-item.h"
struct btrfs_inode_ref *btrfs_find_name_in_backref(const struct extent_buffer *leaf,
int slot,
const struct fscrypt_str *name)
{
struct btrfs_inode_ref *ref;
unsigned long ptr;
unsigned long name_ptr;
u32 item_size;
u32 cur_offset = 0;
int len;
item_size = btrfs_item_size(leaf, slot);
ptr = btrfs_item_ptr_offset(leaf, slot);
while (cur_offset < item_size) {
ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
len = btrfs_inode_ref_name_len(leaf, ref);
name_ptr = (unsigned long)(ref + 1);
cur_offset += len + sizeof(*ref);
if (len != name->len)
continue;
if (memcmp_extent_buffer(leaf, name->name, name_ptr,
name->len) == 0)
return ref;
}
return NULL;
}
struct btrfs_inode_extref *btrfs_find_name_in_ext_backref(
const struct extent_buffer *leaf, int slot, u64 ref_objectid,
const struct fscrypt_str *name)
{
struct btrfs_inode_extref *extref;
unsigned long ptr;
unsigned long name_ptr;
u32 item_size;
u32 cur_offset = 0;
int ref_name_len;
item_size = btrfs_item_size(leaf, slot);
ptr = btrfs_item_ptr_offset(leaf, slot);
/*
* Search all extended backrefs in this item. We're only
* looking through any collisions so most of the time this is
* just going to compare against one buffer. If all is well,
* we'll return success and the inode ref object.
*/
while (cur_offset < item_size) {
extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
name_ptr = (unsigned long)(&extref->name);
ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
if (ref_name_len == name->len &&
btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
(memcmp_extent_buffer(leaf, name->name, name_ptr,
name->len) == 0))
return extref;
cur_offset += ref_name_len + sizeof(*extref);
}
return NULL;
}
/* Returns NULL if no extref found */
struct btrfs_inode_extref *
btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
const struct fscrypt_str *name,
u64 inode_objectid, u64 ref_objectid, int ins_len,
int cow)
{
int ret;
struct btrfs_key key;
key.objectid = inode_objectid;
key.type = BTRFS_INODE_EXTREF_KEY;
key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
if (ret < 0)
return ERR_PTR(ret);
if (ret > 0)
return NULL;
return btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
ref_objectid, name);
}
static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
const struct fscrypt_str *name,
u64 inode_objectid, u64 ref_objectid,
u64 *index)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_inode_extref *extref;
struct extent_buffer *leaf;
int ret;
int del_len = name->len + sizeof(*extref);
unsigned long ptr;
unsigned long item_start;
u32 item_size;
key.objectid = inode_objectid;
key.type = BTRFS_INODE_EXTREF_KEY;
key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0)
ret = -ENOENT;
if (ret < 0)
goto out;
/*
* Sanity check - did we find the right item for this name?
* This should always succeed so error here will make the FS
* readonly.
*/
extref = btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
ref_objectid, name);
if (!extref) {
btrfs_abort_transaction(trans, -ENOENT);
ret = -ENOENT;
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size(leaf, path->slots[0]);
if (index)
*index = btrfs_inode_extref_index(leaf, extref);
if (del_len == item_size) {
/*
* Common case only one ref in the item, remove the
* whole item.
*/
ret = btrfs_del_item(trans, root, path);
goto out;
}
ptr = (unsigned long)extref;
item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
memmove_extent_buffer(leaf, ptr, ptr + del_len,
item_size - (ptr + del_len - item_start));
btrfs_truncate_item(trans, path, item_size - del_len, 1);
out:
btrfs_free_path(path);
return ret;
}
int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root, const struct fscrypt_str *name,
u64 inode_objectid, u64 ref_objectid, u64 *index)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_inode_ref *ref;
struct extent_buffer *leaf;
unsigned long ptr;
unsigned long item_start;
u32 item_size;
u32 sub_item_len;
int ret;
int search_ext_refs = 0;
int del_len = name->len + sizeof(*ref);
key.objectid = inode_objectid;
key.offset = ref_objectid;
key.type = BTRFS_INODE_REF_KEY;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0) {
ret = -ENOENT;
search_ext_refs = 1;
goto out;
} else if (ret < 0) {
goto out;
}
ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0], name);
if (!ref) {
ret = -ENOENT;
search_ext_refs = 1;
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size(leaf, path->slots[0]);
if (index)
*index = btrfs_inode_ref_index(leaf, ref);
if (del_len == item_size) {
ret = btrfs_del_item(trans, root, path);
goto out;
}
ptr = (unsigned long)ref;
sub_item_len = name->len + sizeof(*ref);
item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
item_size - (ptr + sub_item_len - item_start));
btrfs_truncate_item(trans, path, item_size - sub_item_len, 1);
out:
btrfs_free_path(path);
if (search_ext_refs) {
/*
* No refs were found, or we could not find the
* name in our ref array. Find and remove the extended
* inode ref then.
*/
return btrfs_del_inode_extref(trans, root, name,
inode_objectid, ref_objectid, index);
}
return ret;
}
/*
* Insert an extended inode ref into a tree.
*
* The caller must have checked against BTRFS_LINK_MAX already.
*/
static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
const struct fscrypt_str *name,
u64 inode_objectid, u64 ref_objectid,
u64 index)
{
struct btrfs_inode_extref *extref;
int ret;
int ins_len = name->len + sizeof(*extref);
unsigned long ptr;
struct btrfs_path *path;
struct btrfs_key key;
struct extent_buffer *leaf;
key.objectid = inode_objectid;
key.type = BTRFS_INODE_EXTREF_KEY;
key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
ret = btrfs_insert_empty_item(trans, root, path, &key,
ins_len);
if (ret == -EEXIST) {
if (btrfs_find_name_in_ext_backref(path->nodes[0],
path->slots[0],
ref_objectid,
name))
goto out;
btrfs_extend_item(trans, path, ins_len);
ret = 0;
}
if (ret < 0)
goto out;
leaf = path->nodes[0];
ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
ptr += btrfs_item_size(leaf, path->slots[0]) - ins_len;
extref = (struct btrfs_inode_extref *)ptr;
btrfs_set_inode_extref_name_len(path->nodes[0], extref, name->len);
btrfs_set_inode_extref_index(path->nodes[0], extref, index);
btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
ptr = (unsigned long)&extref->name;
write_extent_buffer(path->nodes[0], name->name, ptr, name->len);
btrfs_mark_buffer_dirty(trans, path->nodes[0]);
out:
btrfs_free_path(path);
return ret;
}
/* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root, const struct fscrypt_str *name,
u64 inode_objectid, u64 ref_objectid, u64 index)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_inode_ref *ref;
unsigned long ptr;
int ret;
int ins_len = name->len + sizeof(*ref);
key.objectid = inode_objectid;
key.offset = ref_objectid;
key.type = BTRFS_INODE_REF_KEY;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->skip_release_on_error = 1;
ret = btrfs_insert_empty_item(trans, root, path, &key,
ins_len);
if (ret == -EEXIST) {
u32 old_size;
ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0],
name);
if (ref)
goto out;
old_size = btrfs_item_size(path->nodes[0], path->slots[0]);
btrfs_extend_item(trans, path, ins_len);
ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_ref);
ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
btrfs_set_inode_ref_name_len(path->nodes[0], ref, name->len);
btrfs_set_inode_ref_index(path->nodes[0], ref, index);
ptr = (unsigned long)(ref + 1);
ret = 0;
} else if (ret < 0) {
if (ret == -EOVERFLOW) {
if (btrfs_find_name_in_backref(path->nodes[0],
path->slots[0],
name))
ret = -EEXIST;
else
ret = -EMLINK;
}
goto out;
} else {
ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_ref);
btrfs_set_inode_ref_name_len(path->nodes[0], ref, name->len);
btrfs_set_inode_ref_index(path->nodes[0], ref, index);
ptr = (unsigned long)(ref + 1);
}
write_extent_buffer(path->nodes[0], name->name, ptr, name->len);
btrfs_mark_buffer_dirty(trans, path->nodes[0]);
out:
btrfs_free_path(path);
if (ret == -EMLINK) {
struct btrfs_super_block *disk_super = fs_info->super_copy;
/* We ran out of space in the ref array. Need to
* add an extended ref. */
if (btrfs_super_incompat_flags(disk_super)
& BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
ret = btrfs_insert_inode_extref(trans, root, name,
inode_objectid,
ref_objectid, index);
}
return ret;
}
int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 objectid)
{
struct btrfs_key key;
int ret;
key.objectid = objectid;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_insert_empty_item(trans, root, path, &key,
sizeof(struct btrfs_inode_item));
return ret;
}
int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path,
struct btrfs_key *location, int mod)
{
int ins_len = mod < 0 ? -1 : 0;
int cow = mod != 0;
int ret;
int slot;
struct extent_buffer *leaf;
struct btrfs_key found_key;
ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
if (ret > 0 && location->type == BTRFS_ROOT_ITEM_KEY &&
location->offset == (u64)-1 && path->slots[0] != 0) {
slot = path->slots[0] - 1;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, slot);
if (found_key.objectid == location->objectid &&
found_key.type == location->type) {
path->slots[0]--;
return 0;
}
}
return ret;
}
static inline void btrfs_trace_truncate(const struct btrfs_inode *inode,
const struct extent_buffer *leaf,
const struct btrfs_file_extent_item *fi,
u64 offset, int extent_type, int slot)
{
if (!inode)
return;
if (extent_type == BTRFS_FILE_EXTENT_INLINE)
trace_btrfs_truncate_show_fi_inline(inode, leaf, fi, slot,
offset);
else
trace_btrfs_truncate_show_fi_regular(inode, leaf, fi, offset);
}
/*
* Remove inode items from a given root.
*
* @trans: A transaction handle.
* @root: The root from which to remove items.
* @inode: The inode whose items we want to remove.
* @control: The btrfs_truncate_control to control how and what we
* are truncating.
*
* Remove all keys associated with the inode from the given root that have a key
* with a type greater than or equals to @min_type. When @min_type has a value of
* BTRFS_EXTENT_DATA_KEY, only remove file extent items that have an offset value
* greater than or equals to @new_size. If a file extent item that starts before
* @new_size and ends after it is found, its length is adjusted.
*
* Returns: 0 on success, < 0 on error and NEED_TRUNCATE_BLOCK when @min_type is
* BTRFS_EXTENT_DATA_KEY and the caller must truncate the last block.
*/
int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_truncate_control *control)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
struct btrfs_key found_key;
u64 new_size = control->new_size;
u64 extent_num_bytes = 0;
u64 extent_offset = 0;
u64 item_end = 0;
u32 found_type = (u8)-1;
int del_item;
int pending_del_nr = 0;
int pending_del_slot = 0;
int extent_type = -1;
int ret;
u64 bytes_deleted = 0;
bool be_nice = false;
ASSERT(control->inode || !control->clear_extent_range);
ASSERT(new_size == 0 || control->min_type == BTRFS_EXTENT_DATA_KEY);
control->last_size = new_size;
control->sub_bytes = 0;
/*
* For shareable roots we want to back off from time to time, this turns
* out to be subvolume roots, reloc roots, and data reloc roots.
*/
if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
be_nice = true;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = READA_BACK;
key.objectid = control->ino;
key.offset = (u64)-1;
key.type = (u8)-1;
search_again:
/*
* With a 16K leaf size and 128MiB extents, you can actually queue up a
* huge file in a single leaf. Most of the time that bytes_deleted is
* > 0, it will be huge by the time we get here
*/
if (be_nice && bytes_deleted > SZ_32M &&
btrfs_should_end_transaction(trans)) {
ret = -EAGAIN;
goto out;
}
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0)
goto out;
if (ret > 0) {
ret = 0;
/* There are no items in the tree for us to truncate, we're done */
if (path->slots[0] == 0)
goto out;
path->slots[0]--;
}
while (1) {
u64 clear_start = 0, clear_len = 0, extent_start = 0;
bool refill_delayed_refs_rsv = false;
fi = NULL;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
found_type = found_key.type;
if (found_key.objectid != control->ino)
break;
if (found_type < control->min_type)
break;
item_end = found_key.offset;
if (found_type == BTRFS_EXTENT_DATA_KEY) {
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
extent_type = btrfs_file_extent_type(leaf, fi);
if (extent_type != BTRFS_FILE_EXTENT_INLINE)
item_end +=
btrfs_file_extent_num_bytes(leaf, fi);
else if (extent_type == BTRFS_FILE_EXTENT_INLINE)
item_end += btrfs_file_extent_ram_bytes(leaf, fi);
btrfs_trace_truncate(control->inode, leaf, fi,
found_key.offset, extent_type,
path->slots[0]);
item_end--;
}
if (found_type > control->min_type) {
del_item = 1;
} else {
if (item_end < new_size)
break;
if (found_key.offset >= new_size)
del_item = 1;
else
del_item = 0;
}
/* FIXME, shrink the extent if the ref count is only 1 */
if (found_type != BTRFS_EXTENT_DATA_KEY)
goto delete;
control->extents_found++;
if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
u64 num_dec;
clear_start = found_key.offset;
extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
if (!del_item) {
u64 orig_num_bytes =
btrfs_file_extent_num_bytes(leaf, fi);
extent_num_bytes = ALIGN(new_size -
found_key.offset,
fs_info->sectorsize);
clear_start = ALIGN(new_size, fs_info->sectorsize);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_num_bytes);
num_dec = (orig_num_bytes - extent_num_bytes);
if (extent_start != 0)
control->sub_bytes += num_dec;
btrfs_mark_buffer_dirty(trans, leaf);
} else {
extent_num_bytes =
btrfs_file_extent_disk_num_bytes(leaf, fi);
extent_offset = found_key.offset -
btrfs_file_extent_offset(leaf, fi);
/* FIXME blocksize != 4096 */
num_dec = btrfs_file_extent_num_bytes(leaf, fi);
if (extent_start != 0)
control->sub_bytes += num_dec;
}
clear_len = num_dec;
} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
/*
* We can't truncate inline items that have had
* special encodings
*/
if (!del_item &&
btrfs_file_extent_encryption(leaf, fi) == 0 &&
btrfs_file_extent_other_encoding(leaf, fi) == 0 &&
btrfs_file_extent_compression(leaf, fi) == 0) {
u32 size = (u32)(new_size - found_key.offset);
btrfs_set_file_extent_ram_bytes(leaf, fi, size);
size = btrfs_file_extent_calc_inline_size(size);
btrfs_truncate_item(trans, path, size, 1);
} else if (!del_item) {
/*
* We have to bail so the last_size is set to
* just before this extent.
*/
ret = BTRFS_NEED_TRUNCATE_BLOCK;
break;
} else {
/*
* Inline extents are special, we just treat
* them as a full sector worth in the file
* extent tree just for simplicity sake.
*/
clear_len = fs_info->sectorsize;
}
control->sub_bytes += item_end + 1 - new_size;
}
delete:
/*
* We only want to clear the file extent range if we're
* modifying the actual inode's mapping, which is just the
* normal truncate path.
*/
if (control->clear_extent_range) {
ret = btrfs_inode_clear_file_extent_range(control->inode,
clear_start, clear_len);
if (ret) {
btrfs_abort_transaction(trans, ret);
break;
}
}
if (del_item) {
ASSERT(!pending_del_nr ||
((path->slots[0] + 1) == pending_del_slot));
control->last_size = found_key.offset;
if (!pending_del_nr) {
/* No pending yet, add ourselves */
pending_del_slot = path->slots[0];
pending_del_nr = 1;
} else if (path->slots[0] + 1 == pending_del_slot) {
/* Hop on the pending chunk */
pending_del_nr++;
pending_del_slot = path->slots[0];
}
} else {
control->last_size = new_size;
break;
}
if (del_item && extent_start != 0 && !control->skip_ref_updates) {
struct btrfs_ref ref = {
.action = BTRFS_DROP_DELAYED_REF,
.bytenr = extent_start,
.num_bytes = extent_num_bytes,
.owning_root = btrfs_root_id(root),
.ref_root = btrfs_header_owner(leaf),
};
bytes_deleted += extent_num_bytes;
btrfs_init_data_ref(&ref, control->ino, extent_offset,
btrfs_root_id(root), false);
ret = btrfs_free_extent(trans, &ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
break;
}
if (be_nice && btrfs_check_space_for_delayed_refs(fs_info))
refill_delayed_refs_rsv = true;
}
if (found_type == BTRFS_INODE_ITEM_KEY)
break;
if (path->slots[0] == 0 ||
path->slots[0] != pending_del_slot ||
refill_delayed_refs_rsv) {
if (pending_del_nr) {
ret = btrfs_del_items(trans, root, path,
pending_del_slot,
pending_del_nr);
if (ret) {
btrfs_abort_transaction(trans, ret);
break;
}
pending_del_nr = 0;
}
btrfs_release_path(path);
/*
* We can generate a lot of delayed refs, so we need to
* throttle every once and a while and make sure we're
* adding enough space to keep up with the work we are
* generating. Since we hold a transaction here we
* can't flush, and we don't want to FLUSH_LIMIT because
* we could have generated too many delayed refs to
* actually allocate, so just bail if we're short and
* let the normal reservation dance happen higher up.
*/
if (refill_delayed_refs_rsv) {
ret = btrfs_delayed_refs_rsv_refill(fs_info,
BTRFS_RESERVE_NO_FLUSH);
if (ret) {
ret = -EAGAIN;
break;
}
}
goto search_again;
} else {
path->slots[0]--;
}
}
out:
if (ret >= 0 && pending_del_nr) {
int err;
err = btrfs_del_items(trans, root, path, pending_del_slot,
pending_del_nr);
if (err) {
btrfs_abort_transaction(trans, err);
ret = err;
}
}
ASSERT(control->last_size >= new_size);
if (!ret && control->last_size > new_size)
control->last_size = new_size;
btrfs_free_path(path);
return ret;
}