[PATCH] nfsd: Ensure CLONE persists data and metadata changes to the target file

[Trond Myklebust <trondmy@gmail.com>]

The NFSv4.2 CLONE operation has implicit persistence requirements on the
target file, since there is no protocol requirement that the client issue
a separate operation to persist data.
For that reason, we should call vfs_fsync_range() on the destination file
after a successful call to vfs_clone_file_range().

Fixes: ffa0160a1039 ("nfsd: implement the NFSv4.2 CLONE operation")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.5+
---
 fs/nfsd/nfs4proc.c | 3 ++-
 fs/nfsd/vfs.c      | 9 ++++++++-
 fs/nfsd/vfs.h      | 2 +-
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 4e3e77b76411..38c0aeda500e 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1077,7 +1077,8 @@ nfsd4_clone(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		goto out;
 
 	status = nfsd4_clone_file_range(src->nf_file, clone->cl_src_pos,
-			dst->nf_file, clone->cl_dst_pos, clone->cl_count);
+			dst->nf_file, clone->cl_dst_pos, clone->cl_count,
+			EX_ISSYNC(cstate->current_fh.fh_export));
 
 	nfsd_file_put(dst);
 	nfsd_file_put(src);
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index bd0a385df3fc..9d66c4719067 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -525,7 +525,7 @@ __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
 #endif
 
 __be32 nfsd4_clone_file_range(struct file *src, u64 src_pos, struct file *dst,
-		u64 dst_pos, u64 count)
+		u64 dst_pos, u64 count, bool sync)
 {
 	loff_t cloned;
 
@@ -534,6 +534,13 @@ __be32 nfsd4_clone_file_range(struct file *src, u64 src_pos, struct file *dst,
 		return nfserrno(cloned);
 	if (count && cloned != count)
 		return nfserrno(-EINVAL);
+	if (sync) {
+		loff_t dst_end = count ? dst_pos + count - 1 : LLONG_MAX;
+		int status = vfs_fsync_range(dst, dst_pos, dst_end,
+				commit_is_datasync);
+		if (status < 0)
+			return nfserrno(status);
+	}
 	return 0;
 }
 
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index a13fd9d7e1f5..cc110a10bfe8 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -56,7 +56,7 @@ __be32          nfsd4_set_nfs4_label(struct svc_rqst *, struct svc_fh *,
 __be32		nfsd4_vfs_fallocate(struct svc_rqst *, struct svc_fh *,
 				    struct file *, loff_t, loff_t, int);
 __be32		nfsd4_clone_file_range(struct file *, u64, struct file *,
-			u64, u64);
+				       u64, u64, bool);
 #endif /* CONFIG_NFSD_V4 */
 __be32		nfsd_create_locked(struct svc_rqst *, struct svc_fh *,
 				char *name, int len, struct iattr *attrs,
-- 
2.23.0