[PATCH 2/2] xfs: fix splice/direct-IO deadlock

From: Dave Chinner
Date: Mon Jul 18 2011 - 00:05:14 EST

From: Dave Chinner <dchinner@xxxxxxxxxx>

lockdep reports splice vs direct-io write lock inversions due to
generic_file_splice_write() taking the inode->i_mutex inside
XFS_IOLOCK_EXCL context. These lock contexts are inverted, hence can
deadlock. Use generic_file_splice_write_unlocked() because the
i_mutex does not need to be held over the operations that are done
in the XFS splice write path.

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
fs/xfs/linux-2.6/xfs_file.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c
index f51a384..1e641e6 100644
--- a/fs/xfs/linux-2.6/xfs_file.c
+++ b/fs/xfs/linux-2.6/xfs_file.c
@@ -463,7 +463,8 @@ xfs_file_splice_write(

trace_xfs_file_splice_write(ip, count, *ppos, ioflags);

- ret = generic_file_splice_write(pipe, outfilp, ppos, count, flags);
+ ret = generic_file_splice_write_unlocked(pipe, outfilp, ppos,
+ count, flags);

xfs_aio_write_isize_update(inode, ppos, ret);

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