Patch "[PATCH] fix calculation of meta_bg descriptor backups" has been added to the 3.10-stable tree

This is a note to let you know that I've just added the patch titled

[PATCH] fix calculation of meta_bg descriptor backups

to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
fix-calculation-of-meta_bg-descriptor-backups.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Andy Leiserson <[email protected]>
Date: Sun, 18 Oct 2015 00:36:29 -0400
Subject: [PATCH] fix calculation of meta_bg descriptor backups

From: Andy Leiserson <[email protected]>

commit 904dad4742d211b7a8910e92695c0fa957483836 upstream.

"group" is the group where the backup will be placed, and is initialized to zero in the declaration. This meant that backups for meta_bg descriptors were erroneously written to the backup block group descriptors in groups 1 and (desc_per_block-1).

Reproduction information:
mke2fs -Fq -t ext4 -b 1024 -O ^resize_inode /tmp/foo.img 16G truncate -s 24G /tmp/foo.img
losetup /dev/loop0 /tmp/foo.img
mount /dev/loop0 /mnt
resize2fs /dev/loop0
umount /dev/loop0
dd if=/dev/zero of=/dev/loop0 bs=1024 count=2 e2fsck -fy /dev/loop0
losetup -d /dev/loop0

---
 fs/ext4/resize.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -1025,7 +1025,7 @@ exit_free:
  * do not copy the full number of backups at this time.  The resize
  * which changed s_groups_count will backup again.
  */
-static void update_backups(struct super_block *sb, int blk_off, char *data,
+static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
 			   int size, int meta_bg)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);

@@ -1050,7 +1050,7 @@ static void update_backups(struct super_
 		group = ext4_list_backups(sb, &three, &five, &seven);
 		last = sbi->s_groups_count;
 	} else {
-		group = ext4_meta_bg_first_group(sb, group) + 1;
+		group = ext4_get_group_number(sb, blk_off) + 1;
 		last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
 	}
 

Patches currently in stable-queue which might be from [email protected] are

queue-3.10/fix-calculation-of-meta_bg-descriptor-backups.patch