[ 3.5.y.z extended stable ] Patch "Btrfs: don't drop path when printing out tree errors in scrub" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    Btrfs: don't drop path when printing out tree errors in scrub

to the linux-3.5.y-queue branch of the 3.5.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-3.5.y-queue

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

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 482419d72c1198af0d818306161ab30450abac79 Mon Sep 17 00:00:00 2001
From: Josef Bacik <jbacik at fusionio.com>
Date: Fri, 29 Mar 2013 08:09:34 -0600
Subject: [PATCH] Btrfs: don't drop path when printing out tree errors in scrub

commit d8fe29e9dea8d7d61fd140d8779326856478fc62 upstream.

A user reported a panic where we were panicing somewhere in
tree_backref_for_extent from scrub_print_warning.  He only captured the trace
but looking at scrub_print_warning we drop the path right before we mess with
the extent buffer to print out a bunch of stuff, which isn't right.  So fix this
by dropping the path after we use the eb if we need to.  Thanks,

Signed-off-by: Josef Bacik <jbacik at fusionio.com>
Signed-off-by: Chris Mason <chris.mason at fusionio.com>
[ luis: adjust context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/btrfs/scrub.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index b223620..5aeffbe 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -385,7 +385,6 @@ static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
 	eb = path->nodes[0];
 	ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
 	item_size = btrfs_item_size_nr(eb, path->slots[0]);
-	btrfs_release_path(path);

 	if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
 		do {
@@ -401,7 +400,9 @@ static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
 				ret < 0 ? -1 : ref_level,
 				ret < 0 ? -1 : ref_root);
 		} while (ret != 1);
+		btrfs_release_path(path);
 	} else {
+		btrfs_release_path(path);
 		swarn.path = path;
 		iterate_extent_inodes(fs_info, found_key.objectid,
 					extent_item_pos, 1,
--
1.8.1.2