xfs: prevent recursion in xfs_buf_iorequest

If the b_iodone handler is run in calling context in xfs_buf_iorequest we
can run into a recursion where xfs_buf_iodone_callbacks keeps calling back
into xfs_buf_iorequest because an I/O error happened, which keeps calling
back into xfs_buf_iorequest.  This chain will usually not take long
because the filesystem gets shut down because of log I/O errors, but even
over a short time it can cause stack overflows if run on the same context.

As a short term workaround make sure we always call the iodone handler in
workqueue context.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index a4beb42..687b275 100644 (file)
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1243,7 +1243,7 @@ xfs_buf_iorequest(
         */
        atomic_set(&bp->b_io_remaining, 1);
        _xfs_buf_ioapply(bp);
-       _xfs_buf_ioend(bp, 0);
+       _xfs_buf_ioend(bp, 1);
 
        xfs_buf_rele(bp);
 }