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btrfs: factor out the copying loop of dir items from log_dir_items()

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In preparation for the next change, move the loop that processes a leaf
and copies its directory items to the log, into a separate helper
function. This makes the next change simpler and it also helps making
log_dir_items() a bit shorter (specially after the next change).

This patch is part of a patchset comprised of the following 5 patches:

  btrfs: remove root argument from btrfs_log_inode() and its callees
  btrfs: remove redundant log root assignment from log_dir_items()
  btrfs: factor out the copying loop of dir items from log_dir_items()
  btrfs: insert items in batches when logging a directory when possible
  btrfs: keep track of the last logged keys when logging a directory

This is patch 3/5. The change log of the last patch (5/5) has performance
results.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana 2021-09-16 11:32:12 +01:00 committed by David Sterba
parent d46fb845af
commit eb10d85ee7
1 changed files with 75 additions and 60 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

135
fs/btrfs/tree-log.c
View file

@ -3632,6 +3632,66 @@ static noinline int insert_dir_log_key(struct btrfs_trans_handle *trans,
return 0;
}
static int process_dir_items_leaf(struct btrfs_trans_handle *trans,
struct btrfs_inode *inode,
struct btrfs_path *path,
struct btrfs_path *dst_path,
int key_type,
struct btrfs_log_ctx *ctx)
{
struct btrfs_root *log = inode->root->log_root;
struct extent_buffer *src = path->nodes[0];
const int nritems = btrfs_header_nritems(src);
const u64 ino = btrfs_ino(inode);
int i;
for (i = path->slots[0]; i < nritems; i++) {
struct btrfs_key key;
struct btrfs_dir_item *di;
int ret;
btrfs_item_key_to_cpu(src, &key, i);
if (key.objectid != ino || key.type != key_type)
return 1;
ret = overwrite_item(trans, log, dst_path, src, i, &key);
if (ret < 0)
return ret;
/*
* We must make sure that when we log a directory entry, the
* corresponding inode, after log replay, has a matching link
* count. For example:
*
* touch foo
* mkdir mydir
* sync
* ln foo mydir/bar
* xfs_io -c "fsync" mydir
* <crash>
* <mount fs and log replay>
*
* Would result in a fsync log that when replayed, our file inode
* would have a link count of 1, but we get two directory entries
* pointing to the same inode. After removing one of the names,
* it would not be possible to remove the other name, which
* resulted always in stale file handle errors, and would not be
* possible to rmdir the parent directory, since its i_size could
* never be decremented to the value BTRFS_EMPTY_DIR_SIZE,
* resulting in -ENOTEMPTY errors.
*/
di = btrfs_item_ptr(src, i, struct btrfs_dir_item);
btrfs_dir_item_key_to_cpu(src, di, &key);
if ((btrfs_dir_transid(src, di) == trans->transid ||
btrfs_dir_type(src, di) == BTRFS_FT_DIR) &&
key.type != BTRFS_ROOT_ITEM_KEY)
ctx->log_new_dentries = true;
}
return 0;
}
/*
* log all the items included in the current transaction for a given
* directory. This also creates the range items in the log tree required
@ -3647,11 +3707,8 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
struct btrfs_key min_key;
struct btrfs_root *root = inode->root;
struct btrfs_root *log = root->log_root;
struct extent_buffer *src;
int err = 0;
int ret;
int i;
int nritems;
u64 first_offset = min_offset;
u64 last_offset = (u64)-1;
u64 ino = btrfs_ino(inode);
@ -3729,61 +3786,14 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
* from our directory
*/
while (1) {
struct btrfs_key tmp;
src = path->nodes[0];
nritems = btrfs_header_nritems(src);
for (i = path->slots[0]; i < nritems; i++) {
struct btrfs_dir_item *di;
btrfs_item_key_to_cpu(src, &min_key, i);
if (min_key.objectid != ino || min_key.type != key_type)
goto done;
if (need_resched()) {
btrfs_release_path(path);
cond_resched();
goto search;
}
ret = overwrite_item(trans, log, dst_path, src, i,
&min_key);
if (ret) {
ret = process_dir_items_leaf(trans, inode, path, dst_path,
key_type, ctx);
if (ret != 0) {
if (ret < 0)
err = ret;
goto done;
}
/*
* We must make sure that when we log a directory entry,
* the corresponding inode, after log replay, has a
* matching link count. For example:
*
* touch foo
* mkdir mydir
* sync
* ln foo mydir/bar
* xfs_io -c "fsync" mydir
* <crash>
* <mount fs and log replay>
*
* Would result in a fsync log that when replayed, our
* file inode would have a link count of 1, but we get
* two directory entries pointing to the same inode.
* After removing one of the names, it would not be
* possible to remove the other name, which resulted
* always in stale file handle errors, and would not
* be possible to rmdir the parent directory, since
* its i_size could never decrement to the value
* BTRFS_EMPTY_DIR_SIZE, resulting in -ENOTEMPTY errors.
*/
di = btrfs_item_ptr(src, i, struct btrfs_dir_item);
btrfs_dir_item_key_to_cpu(src, di, &tmp);
if ((btrfs_dir_transid(src, di) == trans->transid ||
btrfs_dir_type(src, di) == BTRFS_FT_DIR) &&
tmp.type != BTRFS_ROOT_ITEM_KEY)
ctx->log_new_dentries = true;
goto done;
}
path->slots[0] = nritems;
path->slots[0] = btrfs_header_nritems(path->nodes[0]);
/*
* look ahead to the next item and see if it is also
@ -3797,21 +3807,26 @@ static noinline int log_dir_items(struct btrfs_trans_handle *trans,
err = ret;
goto done;
}
btrfs_item_key_to_cpu(path->nodes[0], &tmp, path->slots[0]);
if (tmp.objectid != ino || tmp.type != key_type) {
btrfs_item_key_to_cpu(path->nodes[0], &min_key, path->slots[0]);
if (min_key.objectid != ino || min_key.type != key_type) {
last_offset = (u64)-1;
goto done;
}
if (btrfs_header_generation(path->nodes[0]) != trans->transid) {
ret = overwrite_item(trans, log, dst_path,
path->nodes[0], path->slots[0],
&tmp);
&min_key);
if (ret)
err = ret;
else
last_offset = tmp.offset;
last_offset = min_key.offset;
goto done;
}
if (need_resched()) {
btrfs_release_path(path);
cond_resched();
goto search;
}
}
done:
btrfs_release_path(path);