[PATCH] xfs: reflink should force the log out if mounted with wsync

["Darrick J. Wong" <darrick.wong@xxxxxxxxxx>]

From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>

Reflink should force the log out to disk if the filesystem was mounted
with wsync, the same as most other operations in xfs.

Fixes: 3fc9f5e409319 ("xfs: remove xfs_reflink_remap_range")
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
 fs/xfs/xfs_file.c    |   21 +++++++++++++++++++--
 fs/xfs/xfs_reflink.c |   15 ++++++++++++++-
 fs/xfs/xfs_reflink.h |    3 ++-
 3 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index b8a4a3f29b36..17bdc5bbc2ae 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1029,8 +1029,10 @@ xfs_file_remap_range(
 	struct inode		*inode_out = file_inode(file_out);
 	struct xfs_inode	*dest = XFS_I(inode_out);
 	struct xfs_mount	*mp = src->i_mount;
+	xfs_lsn_t		sync_lsn = 0;
 	loff_t			remapped = 0;
 	xfs_extlen_t		cowextsize;
+	bool			need_sync;
 	int			ret;
 
 	if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
@@ -1068,13 +1070,28 @@ xfs_file_remap_range(
 		cowextsize = src->i_d.di_cowextsize;
 
 	ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize,
-			remap_flags);
+			remap_flags, &need_sync);
+	if (ret)
+		goto out_unlock;
+
+	/*
+	 * If this is a synchronous mount and xfs_reflink_update_dest didn't
+	 * already take care of this, make sure that the transaction goes to
+	 * disk before returning to the user.
+	 */
+	if (need_sync && xfs_ipincount(dest))
+		sync_lsn = dest->i_itemp->ili_last_lsn;
 
 out_unlock:
 	xfs_reflink_remap_unlock(file_in, file_out);
 	if (ret)
 		trace_xfs_reflink_remap_range_error(dest, ret, _RET_IP_);
-	return remapped > 0 ? remapped : ret;
+	if (remapped > 0) {
+		if (sync_lsn)
+			xfs_log_force_lsn(mp, sync_lsn, XFS_LOG_SYNC, NULL);
+		return remapped;
+	}
+	return ret;
 }
 
 STATIC int
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index b0ce04ffd3cd..4f148d58ff98 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -919,12 +919,19 @@ xfs_reflink_update_dest(
 	struct xfs_inode	*dest,
 	xfs_off_t		newlen,
 	xfs_extlen_t		cowextsize,
-	unsigned int		remap_flags)
+	unsigned int		remap_flags,
+	bool			*need_sync)
 {
 	struct xfs_mount	*mp = dest->i_mount;
 	struct xfs_trans	*tp;
 	int			error;
 
+	/*
+	 * If this is a synchronous mount, make sure that the
+	 * transaction goes to disk before returning to the user.
+	 */
+	*need_sync = (mp->m_flags & XFS_MOUNT_WSYNC);
+
 	if (newlen <= i_size_read(VFS_I(dest)) && cowextsize == 0)
 		return 0;
 
@@ -948,6 +955,12 @@ xfs_reflink_update_dest(
 
 	xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE);
 
+	/* We can force the transaction to disk here. */
+	if (*need_sync) {
+		xfs_trans_set_sync(tp);
+		*need_sync = false;
+	}
+
 	error = xfs_trans_commit(tp);
 	if (error)
 		goto out_error;
diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
index 3e4fd46373ab..e9b505e0ad7a 100644
--- a/fs/xfs/xfs_reflink.h
+++ b/fs/xfs/xfs_reflink.h
@@ -55,7 +55,8 @@ extern int xfs_reflink_remap_blocks(struct xfs_inode *src, loff_t pos_in,
 		struct xfs_inode *dest, loff_t pos_out, loff_t remap_len,
 		loff_t *remapped);
 extern int xfs_reflink_update_dest(struct xfs_inode *dest, xfs_off_t newlen,
-		xfs_extlen_t cowextsize, unsigned int remap_flags);
+		xfs_extlen_t cowextsize, unsigned int remap_flags,
+		bool *need_sync);
 extern void xfs_reflink_remap_unlock(struct file *file_in,
 		struct file *file_out);