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authorJin Xu <jinuxstyle@gmail.com>2013-08-05 20:02:04 +0800
committerJaegeuk Kim <jaegeuk.kim@samsung.com>2013-08-06 22:00:36 +0900
commita569469e967022d9ceeaa4b73619f96614087d2d (patch)
tree530ddfa1940ce086cbc7e3711ea01a7c7f783786 /fs/f2fs/gc.c
parentdf273efc36024a9ea97fd687d638a70c3ea8c37a (diff)
downloadop-kernel-dev-a569469e967022d9ceeaa4b73619f96614087d2d.zip
op-kernel-dev-a569469e967022d9ceeaa4b73619f96614087d2d.tar.gz
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 <jinuxstyle@gmail.com> [Jaegeuk Kim: add more cases to use f2fs_wait_on_page_writeback] Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Diffstat (limited to 'fs/f2fs/gc.c')
-rw-r--r--fs/f2fs/gc.c8
1 files changed, 2 insertions, 6 deletions
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index d286d8b..e6b3ffd 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -422,8 +422,7 @@ next_step:
/* set page dirty and write it */
if (gc_type == FG_GC) {
- f2fs_submit_bio(sbi, NODE, true);
- wait_on_page_writeback(node_page);
+ f2fs_wait_on_page_writeback(node_page, NODE, true);
set_page_dirty(node_page);
} else {
if (!PageWriteback(node_page))
@@ -523,10 +522,7 @@ static void move_data_page(struct inode *inode, struct page *page, int gc_type)
} else {
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
- if (PageWriteback(page)) {
- f2fs_submit_bio(sbi, DATA, true);
- wait_on_page_writeback(page);
- }
+ f2fs_wait_on_page_writeback(page, DATA, true);
if (clear_page_dirty_for_io(page) &&
S_ISDIR(inode->i_mode)) {
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