From 86d54795c94532075d862aa0a79f0c981dab4bdd Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Fri, 17 Feb 2017 09:55:55 -0800 Subject: [PATCH] f2fs: do not wait for writeback in write_begin 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 Signed-off-by: Jaegeuk Kim --- fs/f2fs/data.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 8c61fa7..5f3bc98 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -1759,7 +1759,12 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping, 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; -- 2.7.4