ext4: call ext4_ext_drop_refs() from ext4_ext_find_extent()
In nearly all of the calls to ext4_ext_find_extent() where the caller
is trying to recycle the path object, ext4_ext_drop_refs() gets called
to release the buffer heads before the path object gets overwritten.
To simplify things for the callers, and to avoid the possibility of a
memory leak, make ext4_ext_find_extent() responsible for dropping the
buffers.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index ccdd2af..4f4d523 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -867,8 +867,10 @@
eh = ext_inode_hdr(inode);
depth = ext_depth(inode);
- /* account possible depth increase */
- if (!path) {
+ if (path)
+ ext4_ext_drop_refs(path);
+ else {
+ /* account possible depth increase */
path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
GFP_NOFS);
if (unlikely(!path))
@@ -1356,7 +1358,6 @@
goto out;
/* refill path */
- ext4_ext_drop_refs(path);
path = ext4_ext_find_extent(inode,
(ext4_lblk_t)le32_to_cpu(newext->ee_block),
ppath, gb_flags);
@@ -1369,7 +1370,6 @@
goto out;
/* refill path */
- ext4_ext_drop_refs(path);
path = ext4_ext_find_extent(inode,
(ext4_lblk_t)le32_to_cpu(newext->ee_block),
ppath, gb_flags);
@@ -3319,7 +3319,6 @@
* Update path is required because previous ext4_split_extent_at() may
* result in split of original leaf or extent zeroout.
*/
- ext4_ext_drop_refs(path);
path = ext4_ext_find_extent(inode, map->m_lblk, ppath, 0);
if (IS_ERR(path))
return PTR_ERR(path);
@@ -3718,7 +3717,6 @@
EXT4_GET_BLOCKS_CONVERT);
if (err < 0)
return err;
- ext4_ext_drop_refs(path);
path = ext4_ext_find_extent(inode, map->m_lblk, ppath, 0);
if (IS_ERR(path))
return PTR_ERR(path);
@@ -3947,7 +3945,6 @@
EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
if (err < 0)
return err;
- ext4_ext_drop_refs(path);
path = ext4_ext_find_extent(inode, map->m_lblk, ppath, 0);
if (IS_ERR(path))
return PTR_ERR(path);