ceph: fix append mode write

generic_write_checks() may update 'pos', so we need to pass 'pos'
to ceph_sync_write() and ceph_sync_direct_write();
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>

fs/ceph/file.c

@@ -537,7 +537,7 @@ static void ceph_sync_write_unsafe(struct ceph_osd_request *req, bool unsafe)
  * objects, rollback on failure, etc.)
  */
 static ssize_t
-ceph_sync_direct_write(struct kiocb *iocb, struct iov_iter *from)
+ceph_sync_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file);
@@ -553,7 +553,6 @@ ceph_sync_direct_write(struct kiocb *iocb, struct iov_iter *from)
 	int check_caps = 0;
 	int ret;
 	struct timespec mtime = CURRENT_TIME;
-	loff_t pos = iocb->ki_pos;
 	size_t count = iov_iter_count(from);
 
 	if (ceph_snap(file_inode(file)) != CEPH_NOSNAP)
@@ -652,7 +651,8 @@ ceph_sync_direct_write(struct kiocb *iocb, struct iov_iter *from)
  * correct atomic write, we should e.g. take write locks on all
  * objects, rollback on failure, etc.)
  */
-static ssize_t ceph_sync_write(struct kiocb *iocb, struct iov_iter *from)
+static ssize_t
+ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file);
@@ -669,7 +669,6 @@ static ssize_t ceph_sync_write(struct kiocb *iocb, struct iov_iter *from)
 	int check_caps = 0;
 	int ret;
 	struct timespec mtime = CURRENT_TIME;
-	loff_t pos = iocb->ki_pos;
 	size_t count = iov_iter_count(from);
 
 	if (ceph_snap(file_inode(file)) != CEPH_NOSNAP)
@@ -924,9 +923,9 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		/* we might need to revert back to that point */
 		data = *from;
 		if (file->f_flags & O_DIRECT)
-			written = ceph_sync_direct_write(iocb, &data);
+			written = ceph_sync_direct_write(iocb, &data, pos);
 		else
-			written = ceph_sync_write(iocb, &data);
+			written = ceph_sync_write(iocb, &data, pos);
 		if (written == -EOLDSNAPC) {
 			dout("aio_write %p %llx.%llx %llu~%u"
 				"got EOLDSNAPC, retrying\n",