[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20210712060920.291772615@linuxfoundation.org>
Date: Mon, 12 Jul 2021 08:01:12 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, David Sterba <dsterba@...e.com>
Subject: [PATCH 5.13 049/800] btrfs: compression: dont try to compress if we dont have enough pages
From: David Sterba <dsterba@...e.com>
commit f2165627319ffd33a6217275e5690b1ab5c45763 upstream.
The early check if we should attempt compression does not take into
account the number of input pages. It can happen that there's only one
page, eg. a tail page after some ranges of the BTRFS_MAX_UNCOMPRESSED
have been processed, or an isolated page that won't be converted to an
inline extent.
The single page would be compressed but a later check would drop it
again because the result size must be at least one block shorter than
the input. That can never work with just one page.
CC: stable@...r.kernel.org # 4.4+
Signed-off-by: David Sterba <dsterba@...e.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
fs/btrfs/inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -603,7 +603,7 @@ again:
* inode has not been flagged as nocompress. This flag can
* change at any time if we discover bad compression ratios.
*/
- if (inode_need_compress(BTRFS_I(inode), start, end)) {
+ if (nr_pages > 1 && inode_need_compress(BTRFS_I(inode), start, end)) {
WARN_ON(pages);
pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
if (!pages) {
Powered by blists - more mailing lists