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ext4: ensure enough credits in ext4_ext_shift_path_extents

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Like ext4_ext_rm_leaf, we can ensure that there are enough credits
before every call that will consume credits.  As part of this fix we
fold the functionality of ext4_access_path() into
ext4_ext_shift_path_extents().  This change is needed as a preparation
for the next bugfix patch.

Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20210903062748.4118886-3-yangerkun@huawei.com
Signed-off-by: yangerkun <yangerkun@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
yangerkun 2021-09-03 14:27:47 +08:00 committed by Theodore Ts'o
parent 83c5688b89
commit 4268496e48
1 changed files with 15 additions and 34 deletions
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49
fs/ext4/extents.c
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@ -4979,36 +4979,6 @@ int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
return ext4_fill_es_cache_info(inode, start_blk, len_blks, fieinfo);
}
/*
* ext4_access_path:
* Function to access the path buffer for marking it dirty.
* It also checks if there are sufficient credits left in the journal handle
* to update path.
*/
static int
ext4_access_path(handle_t *handle, struct inode *inode,
struct ext4_ext_path *path)
{
int credits, err;
if (!ext4_handle_valid(handle))
return 0;
/*
* Check if need to extend journal credits
* 3 for leaf, sb, and inode plus 2 (bmap and group
* descriptor) for each block group; assume two block
* groups
*/
credits = ext4_writepage_trans_blocks(inode);
err = ext4_datasem_ensure_credits(handle, inode, 7, credits, 0);
if (err < 0)
return err;
err = ext4_ext_get_access(handle, inode, path);
return err;
}
/*
* ext4_ext_shift_path_extents:
* Shift the extents of a path structure lying between path[depth].p_ext
@ -5023,6 +4993,7 @@ ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
int depth, err = 0;
struct ext4_extent *ex_start, *ex_last;
bool update = false;
int credits, restart_credits;
depth = path->p_depth;
while (depth >= 0) {
@ -5032,13 +5003,23 @@ ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
return -EFSCORRUPTED;
ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
/* leaf + sb + inode */
credits = 3;
if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr)) {
update = true;
/* extent tree + sb + inode */
credits = depth + 2;
}
err = ext4_access_path(handle, inode, path + depth);
restart_credits = ext4_writepage_trans_blocks(inode);
err = ext4_datasem_ensure_credits(handle, inode, credits,
restart_credits, 0);
if (err)
goto out;
if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
update = true;
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto out;
while (ex_start <= ex_last) {
if (SHIFT == SHIFT_LEFT) {
@ -5069,7 +5050,7 @@ ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
}
/* Update index too */
err = ext4_access_path(handle, inode, path + depth);
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto out;