diff options
| author | Salman Qazi <sqazi@google.com> | 2012-05-31 23:52:14 -0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2012-06-10 14:41:53 +0100 |
| commit | 4e8e79304ddf4fb1fd350d017347bda0735afd8b (patch) | |
| tree | 654ca2973ae3b39f4077e0b90defc234a3e0c33a /fs | |
| parent | 40fb8cb8f59ccca96bc4ab10b64ac24cabba4ddb (diff) | |
ext4: remove mb_groups before tearing down the buddy_cache
commit 95599968d19db175829fb580baa6b68939b320fb upstream.
We can't have references held on pages in the s_buddy_cache while we are
trying to truncate its pages and put the inode. All the pages must be
gone before we reach clear_inode. This can only be gauranteed if we
can prevent new users from grabbing references to s_buddy_cache's pages.
The original bug can be reproduced and the bug fix can be verified by:
while true; do mount -t ext4 /dev/ram0 /export/hda3/ram0; \
umount /export/hda3/ram0; done &
while true; do cat /proc/fs/ext4/ram0/mb_groups; done
Signed-off-by: Salman Qazi <sqazi@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ext4/mballoc.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 382e4fcb6ced..1d07c1231b7f 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2567,6 +2567,9 @@ int ext4_mb_release(struct super_block *sb) struct ext4_sb_info *sbi = EXT4_SB(sb); struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits); + if (sbi->s_proc) + remove_proc_entry("mb_groups", sbi->s_proc); + if (sbi->s_group_info) { for (i = 0; i < ngroups; i++) { grinfo = ext4_get_group_info(sb, i); @@ -2614,8 +2617,6 @@ int ext4_mb_release(struct super_block *sb) } free_percpu(sbi->s_locality_groups); - if (sbi->s_proc) - remove_proc_entry("mb_groups", sbi->s_proc); return 0; } |