[ 44/47] ext4: remove mb_groups before tearing down the buddy_cache
From: Greg KH
Date: Thu Jun 07 2012 - 00:26:08 EST
3.0-stable review patch. If anyone has any objections, please let me know.
------------------
From: Salman Qazi <sqazi@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/mballoc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2528,6 +2528,9 @@ int ext4_mb_release(struct super_block *
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);
@@ -2575,8 +2578,6 @@ int ext4_mb_release(struct super_block *
}
free_percpu(sbi->s_locality_groups);
- if (sbi->s_proc)
- remove_proc_entry("mb_groups", sbi->s_proc);
return 0;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/