xfs: fix a use after free in xfs_end_io_direct_write

There is a window in which the ioend that we call inode_dio_wake on
in xfs_end_io_direct_write is already free.  Fix this by storing
the inode pointer in a local variable.

This is a fix for the regression introduced in 3.1-rc by
"fs: move inode_dio_done to the end_io handler".

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 63e971e..8c37dde 100644 (file)
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1300,6 +1300,7 @@ xfs_end_io_direct_write(
        bool                    is_async)
 {
        struct xfs_ioend        *ioend = iocb->private;
+       struct inode            *inode = ioend->io_inode;
 
        /*
         * blockdev_direct_IO can return an error even after the I/O
@@ -1331,7 +1332,7 @@ xfs_end_io_direct_write(
        }
 
        /* XXX: probably should move into the real I/O completion handler */
-       inode_dio_done(ioend->io_inode);
+       inode_dio_done(inode);
 }
 
 STATIC ssize_t