This is a note to let you know that I've just added the patch titled
btrfs: fix locking when we put back a delayed ref that's too new
to the 4.4-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:
btrfs-fix-locking-when-we-put-back-a-delayed-ref-that-s-too-new.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d0280996437081dd12ed1e982ac8aeaa62835ec4 Mon Sep 17 00:00:00 2001
From: Jeff Mahoney <jeffm@xxxxxxxx>
Date: Tue, 20 Dec 2016 13:28:28 -0500
Subject: btrfs: fix locking when we put back a delayed ref that's too new
From: Jeff Mahoney <jeffm@xxxxxxxx>
commit d0280996437081dd12ed1e982ac8aeaa62835ec4 upstream.
In __btrfs_run_delayed_refs, when we put back a delayed ref that's too
new, we have already dropped the lock on locked_ref when we set
->processing = 0.
This patch keeps the lock to cover that assignment.
Fixes: d7df2c796d7 (Btrfs: attach delayed ref updates to delayed ref heads)
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
Reviewed-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/extent-tree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2520,11 +2520,11 @@ static noinline int __btrfs_run_delayed_
if (ref && ref->seq &&
btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
spin_unlock(&locked_ref->lock);
- btrfs_delayed_ref_unlock(locked_ref);
spin_lock(&delayed_refs->lock);
locked_ref->processing = 0;
delayed_refs->num_heads_ready++;
spin_unlock(&delayed_refs->lock);
+ btrfs_delayed_ref_unlock(locked_ref);
locked_ref = NULL;
cond_resched();
count++;
Patches currently in stable-queue which might be from jeffm@xxxxxxxx are
queue-4.4/btrfs-fix-error-handling-when-run_delayed_extent_op-fails.patch
queue-4.4/btrfs-fix-locking-when-we-put-back-a-delayed-ref-that-s-too-new.patch
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