f2fs: fix race in between GC and atomic open
Thread GC thread
- f2fs_ioc_start_atomic_write
- get_dirty_pages
- filemap_write_and_wait_range
- f2fs_gc
- do_garbage_collect
- gc_data_segment
- move_data_page
- f2fs_is_atomic_file
- set_page_dirty
- set_inode_flag(, FI_ATOMIC_FILE)
Dirty data page can still be generated by GC in race condition as
above call stack.
This patch adds fi->dio_rwsem[WRITE] in f2fs_ioc_start_atomic_write
to avoid such race.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index f639b5f..18be1890 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1677,6 +1677,8 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
inode_lock(inode);
+ down_write(&F2FS_I(inode)->dio_rwsem[WRITE]);
+
if (f2fs_is_atomic_file(inode))
goto out;
@@ -1706,6 +1708,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
stat_inc_atomic_write(inode);
stat_update_max_atomic_write(inode);
out:
+ up_write(&F2FS_I(inode)->dio_rwsem[WRITE]);
inode_unlock(inode);
mnt_drop_write_file(filp);
return ret;