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[3.8.y.z,extended,stable] Patch "ext4: make sure group number is bumped after a inode allocation race" has been added to staging queue

Message ID 1376606873-22011-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa Aug. 15, 2013, 10:47 p.m. UTC 
This is a note to let you know that I have just added a patch titled

    ext4: make sure group number is bumped after a inode allocation race

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.7.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

From d6adb3acc2c31bea57bae9aab0558528b35259d4 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Fri, 26 Jul 2013 15:15:46 -0400
Subject: ext4: make sure group number is bumped after a inode allocation race

commit a34eb503742fd25155fd6cff6163daacead9fbc3 upstream.

When we try to allocate an inode, and there is a race between two
CPU's trying to grab the same inode, _and_ this inode is the last free
inode in the block group, make sure the group number is bumped before
we continue searching the rest of the block groups.  Otherwise, we end
up searching the current block group twice, and we end up skipping
searching the last block group.  So in the unlikely situation where
almost all of the inodes are allocated, it's possible that we will
return ENOSPC even though there might be free inodes in that last
block group.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 fs/ext4/ialloc.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--
1.8.1.2
diff mbox

Patch

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index ec2909e..f4da2a3 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -715,11 +715,8 @@  repeat_in_this_group:
 		ino = ext4_find_next_zero_bit((unsigned long *)
 					      inode_bitmap_bh->b_data,
 					      EXT4_INODES_PER_GROUP(sb), ino);
-		if (ino >= EXT4_INODES_PER_GROUP(sb)) {
-			if (++group == ngroups)
-				group = 0;
-			continue;
-		}
+		if (ino >= EXT4_INODES_PER_GROUP(sb))
+			goto next_group;
 		if (group == 0 && (ino+1) < EXT4_FIRST_INO(sb)) {
 			ext4_error(sb, "reserved inode found cleared - "
 				   "inode=%lu", ino + 1);
@@ -737,6 +734,9 @@  repeat_in_this_group:
 			goto got; /* we grabbed the inode! */
 		if (ino < EXT4_INODES_PER_GROUP(sb))
 			goto repeat_in_this_group;
+next_group:
+		if (++group == ngroups)
+			group = 0;
 	}
 	err = -ENOSPC;
 	goto out;