[41/53] ext4: fix ext4_end_io_dio() racing against fsync()
From: Greg KH
Date: Fri Dec 16 2011 - 14:50:53 EST
3.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Theodore Ts'o <tytso@xxxxxxx>
commit b5a7e97039a80fae673ccc115ce595d5b88fb4ee upstream.
We need to make sure iocb->private is cleared *before* we put the
io_end structure on i_completed_io_list. Otherwise fsync() could
potentially run on another CPU and free the iocb structure out from
under us.
Reported-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
fs/ext4/inode.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2630,10 +2630,11 @@ static void ext4_end_io_dio(struct kiocb
iocb->private, io_end->inode->i_ino, iocb, offset,
size);
+ iocb->private = NULL;
+
/* if not aio dio with unwritten extents, just free io and return */
if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
ext4_free_io_end(io_end);
- iocb->private = NULL;
out:
if (is_async)
aio_complete(iocb, ret, 0);
@@ -2656,7 +2657,6 @@ out:
spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
/* queue the work to convert unwritten extents to written */
- iocb->private = NULL;
queue_work(wq, &io_end->work);
/* XXX: probably should move into the real I/O completion handler */
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/