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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "David Sterba" <dsterba@suse.com>,
        "Filipe Manana" <fdmanana@suse.com>,
        "Omar Sandoval" <osandov@fb.com>
Date:   Sun, 11 Nov 2018 19:49:05 +0000
Message-ID: <lsq.1541965745.152881364@decadent.org.uk>
Subject: [PATCH 3.16 091/366] Btrfs: reserve space for O_TMPFILE orphan
 item deletion
In-Reply-To: <lsq.1541965744.387173642@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Omar Sandoval <osandov@fb.com>

commit 399b0bbf5f680797d3599fa14f16706ffc470145 upstream.

btrfs_link() calls btrfs_orphan_del() if it's linking an O_TMPFILE but
it doesn't reserve space to do so. Even before the removal of the
orphan_block_rsv it wasn't using it.

Fixes: ef3b9af50bfa ("Btrfs: implement inode_operations callback tmpfile")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 fs/btrfs/inode.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6142,8 +6142,9 @@ static int btrfs_link(struct dentry *old
 	 * 2 items for inode and inode ref
 	 * 2 items for dir items
 	 * 1 item for parent inode
+	 * 1 item for orphan item deletion if O_TMPFILE
 	 */
-	trans = btrfs_start_transaction(root, 5);
+	trans = btrfs_start_transaction(root, inode->i_nlink ? 5 : 6);
 	if (IS_ERR(trans)) {
 		err = PTR_ERR(trans);
 		goto fail;