Call splice_from_pipe directly from XFS so that we can do our normal
I/O path locking. This fixes a rare to hit deadlock vs direct I/O
as reported by Dave Chinner long time ago.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/xfs/xfs_file.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 52c91e1..9d0da98 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -43,6 +43,7 @@
#include <linux/dcache.h>
#include <linux/falloc.h>
#include <linux/pagevec.h>
+#include <linux/splice.h>
static const struct vm_operations_struct xfs_file_vm_ops;
@@ -348,14 +349,6 @@ xfs_file_splice_read(
return ret;
}
-/*
- * xfs_file_splice_write() does not use xfs_rw_ilock() because
- * generic_file_splice_write() takes the i_mutex itself. This, in theory,
- * couuld cause lock inversions between the aio_write path and the splice path
- * if someone is doing concurrent splice(2) based writes and write(2) based
- * writes to the same inode. The only real way to fix this is to re-implement
- * the generic code here with correct locking orders.
- */
STATIC ssize_t
xfs_file_splice_write(
struct pipe_inode_info *pipe,
@@ -377,15 +370,22 @@ xfs_file_splice_write(
if (XFS_FORCED_SHUTDOWN(ip->i_mount))
return -EIO;
- xfs_ilock(ip, XFS_IOLOCK_EXCL);
-
+ xfs_rw_ilock(ip, XFS_IOLOCK_EXCL);
trace_xfs_file_splice_write(ip, count, *ppos, ioflags);
+ ret = splice_from_pipe(pipe, outfilp, ppos, count, flags, pipe_to_file);
+ xfs_rw_iunlock(ip, XFS_IOLOCK_EXCL);
+
+ if (ret > 0) {
+ int err;
- ret = generic_file_splice_write(pipe, outfilp, ppos, count, flags);
- if (ret > 0)
XFS_STATS_ADD(xs_write_bytes, ret);
- xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+ err = generic_write_sync(outfilp, *ppos, ret);
+ if (err)
+ return err;
+ *ppos += ret;
+ }
+
return ret;
}
--
1.7.10.4
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