On 12/4/12 6:11 AM, Forrest Liu wrote:
> Extent indexes didn't update correctly in ext4_ext_rm_idx, when depth
> of extent tree is greater than 1.
This is interesting; we had 2 reports of similar corruption on the
list, I wonder if the application in question was doing hole punching.
I didn't expect that they were, so TBH I was pretty much ignoring
the hole-punch cases for parent index updates. Hm. I'll have
to look into that.
Could you turn your testcase into an xfstest regression test?
-Eric
> Signed-off-by: Forrest Liu <forrestl@xxxxxxxxxxxx>
> ---
> fs/ext4/extents.c | 24 ++++++++++++++++++++----
> 1 files changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index d3dd618..b10b8c0 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -2190,13 +2190,15 @@ 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;
> + __le32 border;
>
> /* 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 +2223,20 @@ static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
>
> ext4_free_blocks(handle, inode, NULL, leaf, 1,
> EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
> +
> + border = path->p_idx->ei_block;
> + 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 = border;
> + err = ext4_ext_dirty(handle, inode, path);
> + if (err)
> + break;
> + }
> return err;
> }
>
> @@ -2557,7 +2573,7 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
> /* 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 +2776,7 @@ 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);
>
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