smb3: directory sync should not return an error

commit 6e70c267e68d77679534dcf4aaf84e66f2cf1425 upstream.

As with NFS, which ignores sync on directory handles,
fsync on a directory handle is a noop for CIFS/SMB3.
Do not return an error on it.  It breaks some database
apps otherwise.

Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index a0bf3f135a92a0245da0ac7f3dd47a0d14bf4123..bd6ebe78809de05ad55a38c7e16a228c0d276943 100644 (file)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -899,6 +899,18 @@ const struct inode_operations cifs_symlink_inode_ops = {
 #endif
 };
 
+/*
+ * Directory operations under CIFS/SMB2/SMB3 are synchronous, so fsync()
+ * is a dummy operation.
+ */
+static int cifs_dir_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+       cifs_dbg(FYI, "Sync directory - name: %pD datasync: 0x%x\n",
+                file, datasync);
+
+       return 0;
+}
+
 const struct file_operations cifs_file_ops = {
        .read = new_sync_read,
        .write = new_sync_write,
@@ -1018,6 +1030,7 @@ const struct file_operations cifs_dir_ops = {
        .read    = generic_read_dir,
        .unlocked_ioctl  = cifs_ioctl,
        .llseek = generic_file_llseek,
+       .fsync = cifs_dir_fsync,
 };
 
 static void