This is a note to let you know that I've just added the patch titled
f2fs: do not wait for writeback in write_begin
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:
f2fs-do-not-wait-for-writeback-in-write_begin.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 foo@baz Thu Oct 19 15:15:46 CEST 2017
From: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Date: Fri, 17 Feb 2017 09:55:55 -0800
Subject: f2fs: do not wait for writeback in write_begin
From: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
[ Upstream commit 86d54795c94532075d862aa0a79f0c981dab4bdd ]
Otherwise we can get livelock like below.
[79880.428136] dbench D 0 18405 18404 0x00000000
[79880.428139] Call Trace:
[79880.428142] __schedule+0x219/0x6b0
[79880.428144] schedule+0x36/0x80
[79880.428147] schedule_timeout+0x243/0x2e0
[79880.428152] ? update_sd_lb_stats+0x16b/0x5f0
[79880.428155] ? ktime_get+0x3c/0xb0
[79880.428157] io_schedule_timeout+0xa6/0x110
[79880.428161] __lock_page+0xf7/0x130
[79880.428164] ? unlock_page+0x30/0x30
[79880.428167] pagecache_get_page+0x16b/0x250
[79880.428171] grab_cache_page_write_begin+0x20/0x40
[79880.428182] f2fs_write_begin+0xa2/0xdb0 [f2fs]
[79880.428192] ? f2fs_mark_inode_dirty_sync+0x16/0x30 [f2fs]
[79880.428197] ? kmem_cache_free+0x79/0x200
[79880.428203] ? __mark_inode_dirty+0x17f/0x360
[79880.428206] generic_perform_write+0xbb/0x190
[79880.428213] ? file_update_time+0xa4/0xf0
[79880.428217] __generic_file_write_iter+0x19b/0x1e0
[79880.428226] f2fs_file_write_iter+0x9c/0x180 [f2fs]
[79880.428231] __vfs_write+0xc5/0x140
[79880.428235] vfs_write+0xb2/0x1b0
[79880.428238] SyS_write+0x46/0xa0
[79880.428242] entry_SYSCALL_64_fastpath+0x1e/0xad
Fixes: cae96a5c8ab6 ("f2fs: check io submission more precisely")
Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/f2fs/data.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1416,7 +1416,12 @@ static int f2fs_write_begin(struct file
goto fail;
}
repeat:
- page = grab_cache_page_write_begin(mapping, index, flags);
+ /*
+ * Do not use grab_cache_page_write_begin() to avoid deadlock due to
+ * wait_for_stable_page. Will wait that below with our IO control.
+ */
+ page = pagecache_get_page(mapping, index,
+ FGP_LOCK | FGP_WRITE | FGP_CREAT, GFP_NOFS);
if (!page) {
err = -ENOMEM;
goto fail;
Patches currently in stable-queue which might be from jaegeuk@xxxxxxxxxx are
queue-4.4/f2fs-do-not-wait-for-writeback-in-write_begin.patch