2013-10-08 01:28:33

by Jaegeuk Kim

[permalink] [raw]
Subject: [PATCH] f2fs: fix writing incorrect orphan blocks

Previously, there was a erroneous scenario like below.
thread 1: thread 2:
f2fs_unlink
- acquire_orphan_inode
: sbi->n_orphans++ write_checkpoint
- block_operations
: f2fs_lock_all
- do_checkpoint
: write orphan blocks with sbi->n_orphans
- unblock_operations
- f2fs_lock_op
- release_orphan_inode
- f2fs_unlock_op

During the checkpoint by thread 2, f2fs stores a wrong orphan block according
to the wrong sbi->n_orphans.
To avoid this, simply we should make cover acquire_orphan_inode too with
f2fs_lock_op.

Signed-off-by: Jaegeuk Kim <[email protected]>
---
fs/f2fs/namei.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 29f73fd..575adac 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -228,14 +228,14 @@ static int f2fs_unlink(struct inode *dir, struct dentry *dentry)
if (!de)
goto fail;

+ f2fs_lock_op(sbi);
err = acquire_orphan_inode(sbi);
if (err) {
+ f2fs_unlock_op(sbi);
kunmap(page);
f2fs_put_page(page, 0);
goto fail;
}
-
- f2fs_lock_op(sbi);
f2fs_delete_entry(de, page, inode);
f2fs_unlock_op(sbi);

--
1.8.4.474.g128a96c