On Fri, Aug 29, 2014 at 12:12:02PM -0700, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
>
> This is a note to let you know that I've just added the patch titled
>
> ext4: fix ext4_discard_allocated_blocks() if we can't allocate the pa struct
>
> From 86f0afd463215fc3e58020493482faa4ac3a4d69 Mon Sep 17 00:00:00 2001
Hi Greg,
Please sure you also grab this commit (which just hit mainline today,
along with a bunch of other ext4 patches marked for the stable kernel)
as well, since this commit fixes a bug introduced by "86f0afd46321:
ext4: fix ext4_discard_allocated_blocks() if we can't allocate the pa
struct".
Cheers,
- Ted
commit c99d1e6e83b06744c75d9f5e491ed495a7086b7b
Author: Theodore Ts'o <tytso@xxxxxxx>
Date: Sat Aug 23 17:47:28 2014 -0400
ext4: fix BUG_ON in mb_free_blocks()
If we suffer a block allocation failure (for example due to a memory
allocation failure), it's possible that we will call
ext4_discard_allocated_blocks() before we've actually allocated any
blocks. In that case, fe_len and fe_start in ac->ac_f_ex will still
be zero, and this will result in mb_free_blocks(inode, e4b, 0, 0)
triggering the BUG_ON on mb_free_blocks():
BUG_ON(last >= (sb->s_blocksize << 3));
Fix this by bailing out of ext4_discard_allocated_blocks() if fs_len
is zero.
Also fix a missing ext4_mb_unload_buddy() call in
ext4_discard_allocated_blocks().
Google-Bug-Id: 16844242
Fixes: 86f0afd463215fc3e58020493482faa4ac3a4d69
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
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