Commits
Yunlei He committed d40a43af0a5
f2fs: fix an infinite loop when flush nodes in cp
Thread A Thread B
- write_checkpoint
- block_operations
-blk_start_plug
-sync_node_pages - f2fs_do_sync_file
- fsync_node_pages
- f2fs_wait_on_page_writeback
Thread A wait for global F2FS_DIRTY_NODES decreased to zero,
it start a plug list, some requests have been added to this list.
Thread B lock one dirty node page, and wait this page write back.
But this page has been in plug list of thread A with PG_writeback flag.
Thread A keep on running and its plug list has no chance to finish,
so it seems a deadlock between cp and fsync path.
This patch add a wait on page write back before set node page dirty
to avoid this problem.
Signed-off-by: Yunlei He <heyunlei@huawei.com>
Signed-off-by: Pengyang Hou <houpengyang@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>