[ 109/221] ext4: fix extent tree corruption caused by hole punch

Greg Kroah-Hartman
2013-01-15T22:31:37Z

From: Forrest Liu <forrestl@synology.com>

commit c36575e663e302dbaa4d16b9c72d2c9a913a9aef upstream.

When depth of extent tree is greater than 1, logical start value of
interior node is not correctly updated in ext4_ext_rm_idx.

Signed-off-by: Forrest Liu <forrestl@synology.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Ashish Sangwan <ashishsangwan2@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/ext4/extents.c | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)

--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2190,13 +2190,14 @@ errout:
* removes index from the index block.
*/
static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
- struct ext4_ext_path *path)
+ struct ext4_ext_path *path, int depth)
{
int err;
ext4_fsblk_t leaf;

/* free index block */
- path--;
+ depth--;
+ path = path + depth;
leaf = ext4_idx_pblock(path->p_idx);
if (unlikely(path->p_hdr->eh_entries == 0)) {
EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
@@ -2221,6 +2222,19 @@ static int ext4_ext_rm_idx(handle_t *han

ext4_free_blocks(handle, inode, NULL, leaf, 1,
EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
+
+ while (--depth >= 0) {
+ if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
+ break;
+ path--;
+ err = ext4_ext_get_access(handle, inode, path);
+ if (err)
+ break;
+ path->p_idx->ei_block = (path+1)->p_idx->ei_block;
+ err = ext4_ext_dirty(handle, inode, path);
+ if (err)
+ break;
+ }
return err;
}

@@ -2557,7 +2571,7 @@ ext4_ext_rm_leaf(handle_t *handle, struc
/* if this leaf is free, then we should
* remove it from index block above */
if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
- err = ext4_ext_rm_idx(handle, inode, path + depth);
+ err = ext4_ext_rm_idx(handle, inode, path, depth);

out:
return err;
@@ -2760,7 +2774,7 @@ again:
/* index is empty, remove it;
* handle must be already prepared by the
* truncatei_leaf() */
- err = ext4_ext_rm_idx(handle, inode, path + i);
+ err = ext4_ext_rm_idx(handle, inode, path, i);
}
/* root level has p_bh == NULL, brelse() eats this */
brelse(path[i].p_bh);