From a569469e967022d9ceeaa4b73619f96614087d2d Mon Sep 17 00:00:00 2001 From: Jin Xu Date: Mon, 5 Aug 2013 20:02:04 +0800 Subject: f2fs: fix a deadlock in fsync This patch fixes a deadlock bug that occurs quite often when there are concurrent write and fsync on a same file. Following is the simplified call trace when tasks get hung. fsync thread: - f2fs_sync_file ... - f2fs_write_data_pages ... - update_extent_cache ... - update_inode - wait_on_page_writeback bdi writeback thread - __writeback_single_inode - f2fs_write_data_pages - mutex_lock(sbi->writepages) The deadlock happens when the fsync thread waits on a inode page that has been added to the f2fs' cached bio sbi->bio[NODE], and unfortunately, no one else could be able to submit the cached bio to block layer for writeback. This is because the fsync thread already hold a sbi->fs_lock and the sbi->writepages lock, causing the bdi thread being blocked when attempt to write data pages for the same inode. At the same time, f2fs_gc thread does not notice the situation and could not help. Even the sync syscall gets blocked. To fix it, we could submit the cached bio first before waiting on a inode page that is being written back. Signed-off-by: Jin Xu [Jaegeuk Kim: add more cases to use f2fs_wait_on_page_writeback] Signed-off-by: Jaegeuk Kim --- fs/f2fs/data.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/f2fs/data.c') diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index f458883af815..a7eb52925723 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -37,7 +37,7 @@ static void __set_data_blkaddr(struct dnode_of_data *dn, block_t new_addr) struct page *node_page = dn->node_page; unsigned int ofs_in_node = dn->ofs_in_node; - wait_on_page_writeback(node_page); + f2fs_wait_on_page_writeback(node_page, NODE, false); rn = F2FS_NODE(node_page); -- cgit v1.2.2