xfs: update atime before I/O in xfs_file_dio_aio_read

After the call to __blkdev_direct_IO the final reference to the file
might have been dropped by aio_complete already, and the call to
file_accessed might cause a use after free.

Instead update the access time before the I/O, similar to how we
update the time stamps before writes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-and-tested-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index e612a02..b927ea9 100644 (file)
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -269,6 +269,8 @@ xfs_file_dio_aio_read(
                return -EINVAL;
        }
 
+       file_accessed(iocb->ki_filp);
+
        /*
         * Locking is a bit tricky here. If we take an exclusive lock for direct
         * IO, we effectively serialise all new concurrent read IO to this file
@@ -323,7 +325,6 @@ xfs_file_dio_aio_read(
        }
        xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
 
-       file_accessed(iocb->ki_filp);
        return ret;
 }