linux-kernel - [PATCH 3.2 071/153] Btrfs: fix extent state leak from tree log

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Message-ID: <lsq.1527677561.593313924@decadent.org.uk>
Date:   Wed, 30 May 2018 11:52:41 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "David Sterba" <dsterba@...e.com>,
        "Liu Bo" <bo.li.liu@...cle.com>, "Josef Bacik" <jbacik@...com>
Subject: [PATCH 3.2 071/153] Btrfs: fix extent state leak from tree log

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

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

From: Liu Bo <bo.li.liu@...cle.com>

commit 55237a5f2431a72435e3ed39e4306e973c0446b7 upstream.

It's possible that btrfs_sync_log() bails out after one of the two
btrfs_write_marked_extents() which convert extent state's state bit into
EXTENT_NEED_WAIT from EXTENT_DIRTY/EXTENT_NEW, however only EXTENT_DIRTY
and EXTENT_NEW are searched by free_log_tree() so that those extent states
with EXTENT_NEED_WAIT lead to memory leak.

Signed-off-by: Liu Bo <bo.li.liu@...cle.com>
Reviewed-by: Josef Bacik <jbacik@...com>
Signed-off-by: David Sterba <dsterba@...e.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/btrfs/tree-log.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2216,12 +2216,13 @@ static void free_log_tree(struct btrfs_t
 
 	while (1) {
 		ret = find_first_extent_bit(&log->dirty_log_pages,
-				0, &start, &end, EXTENT_DIRTY | EXTENT_NEW);
+				0, &start, &end,
+				EXTENT_DIRTY | EXTENT_NEW | EXTENT_NEED_WAIT);
 		if (ret)
 			break;
 
 		clear_extent_bits(&log->dirty_log_pages, start, end,
-				  EXTENT_DIRTY | EXTENT_NEW, GFP_NOFS);
+				  EXTENT_DIRTY | EXTENT_NEW | EXTENT_NEED_WAIT, GFP_NOFS);
 	}
 
 	free_extent_buffer(log->node);