Patchwork [3.5.y.z,extended,stable] Patch "Btrfs: re-add root to dead root list if we stop dropping it" has been added to staging queue

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Submitter Luis Henriques
Date Aug. 4, 2013, 9:49 a.m.
Message ID <1375609768-11374-1-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/264476/
State New
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Luis Henriques - Aug. 4, 2013, 9:49 a.m.
This is a note to let you know that I have just added a patch titled

    Btrfs: re-add root to dead root list if we stop dropping it

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 40de2332062ada6679c390502aadd852f156d786 Mon Sep 17 00:00:00 2001
From: Josef Bacik <jbacik@fusionio.com>
Date: Wed, 17 Jul 2013 19:30:20 -0400
Subject: [PATCH] Btrfs: re-add root to dead root list if we stop dropping it

commit d29a9f629e009c9b90e5859bce581070fd6247fc upstream.

If we stop dropping a root for whatever reason we need to add it back to the
dead root list so that we will re-start the dropping next transaction commit.
The other case this happens is if we recover a drop because we will add a root
without adding it to the fs radix tree, so we can leak it's root and commit root
extent buffer, adding this to the dead root list makes this cleanup happen.
Thanks,

Reported-by: Alex Lyakas <alex.btrfs@zadarastorage.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 fs/btrfs/extent-tree.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

--
1.8.3.2

Patch

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 9b1dc7b..6bb1213 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6848,6 +6848,7 @@  int btrfs_drop_snapshot(struct btrfs_root *root,
 	int err = 0;
 	int ret;
 	int level;
+	bool root_dropped = false;

 	path = btrfs_alloc_path();
 	if (!path) {
@@ -7018,12 +7019,22 @@  int btrfs_drop_snapshot(struct btrfs_root *root,
 		free_extent_buffer(root->commit_root);
 		kfree(root);
 	}
+	root_dropped = true;
 out_end_trans:
 	btrfs_end_transaction_throttle(trans, tree_root);
 out_free:
 	kfree(wc);
 	btrfs_free_path(path);
 out:
+	/*
+	 * So if we need to stop dropping the snapshot for whatever reason we
+	 * need to make sure to add it back to the dead root list so that we
+	 * keep trying to do the work later.  This also cleans up roots if we
+	 * don't have it in the radix (like when we recover after a power fail
+	 * or unmount) so we don't leak memory.
+	 */
+	if (root_dropped == false)
+		btrfs_add_dead_root(root);
 	if (err)
 		btrfs_std_error(root->fs_info, err);
 	return err;