From: yangerkun
maillist inclusion
category: bugfix
issue: #I4NRS5
CVE: NA
Signed-off-by: Yu Changchun
---------------------------
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
Reviewed-by: Jan Kara
Signed-off-by: Theodore Ts'o
Reviewed-by: Zhang Yi
Signed-off-by: Chen Jun
Signed-off-by: Zheng Zengkai
Signed-off-by: Yu Changchun
---
fs/ext4/extents.c | 49 +++++++++++++++--------------------------------
1 file changed, 15 insertions(+), 34 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 74b69d83c198..a16be67a1fe8 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -5014,36 +5014,6 @@ 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
@@ -5058,6 +5028,7 @@ 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) {
@@ -5067,13 +5038,23 @@ 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) {
@@ -5104,7 +5085,7 @@ 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;
--
2.25.1
