xfs: pull up dfops from xfs_itruncate_extents()

xfs_itruncate_extents[_flags]() uses a local dfops with a
transaction provided by the caller. It uses hacky ->t_dfops
replacement logic to avoid stomping over an already populated
->t_dfops.

The latter never occurs for current callers and the logic itself is
not really appropriate. Clean this up by updating all callers to
initialize a dfops and to use that down in xfs_itruncate_extents().
This more closely resembles the upcoming logic where dfops will be
embedded within the transaction. We can also replace the
xfs_defer_init() in the xfs_itruncate_extents_flags() loop with an
assert. Both dfops and firstblock should be in a valid state
after xfs_defer_finish() and the inode joined to the dfops is fixed
throughout the loop.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 0fa29f39d658..704b57a8b99e 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -26,6 +26,7 @@
 #include "xfs_dir2.h"
 #include "xfs_trans_space.h"
 #include "xfs_iomap.h"
+#include "xfs_defer.h"
 
 #include <linux/capability.h>
 #include <linux/xattr.h>
@@ -812,6 +813,7 @@ xfs_setattr_size(
 	struct inode		*inode = VFS_I(ip);
 	xfs_off_t		oldsize, newsize;
 	struct xfs_trans	*tp;
+	struct xfs_defer_ops	dfops;
 	int			error;
 	uint			lock_flags = 0;
 	bool			did_zeroing = false;
@@ -915,6 +917,7 @@ xfs_setattr_size(
 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
 	if (error)
 		return error;
+	xfs_defer_init(tp, &dfops);
 
 	lock_flags |= XFS_ILOCK_EXCL;
 	xfs_ilock(ip, XFS_ILOCK_EXCL);