CIFS: Add brlock support for SMB2

Signed-off-by: Pavel Shilovsky <pshilovsky@etersoft.ru>

1 files changed, 97 insertions, 0 deletions

diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index 5ff25e025215..a25ea02149e7 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -104,3 +104,100 @@ out:
 	kfree(smb2_path);
 	return rc;
 }
+
+int
+smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
+		  const unsigned int xid)
+{
+	int rc = 0, stored_rc;
+	unsigned int max_num, num = 0, max_buf;
+	struct smb2_lock_element *buf, *cur;
+	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
+	struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
+	struct cifsLockInfo *li, *tmp;
+	__u64 length = 1 + flock->fl_end - flock->fl_start;
+	struct list_head tmp_llist;
+
+	INIT_LIST_HEAD(&tmp_llist);
+
+	/*
+	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
+	 * and check it for zero before using.
+	 */
+	max_buf = tcon->ses->server->maxBuf;
+	if (!max_buf)
+		return -EINVAL;
+
+	max_num = max_buf / sizeof(struct smb2_lock_element);
+	buf = kzalloc(max_num * sizeof(struct smb2_lock_element), GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	cur = buf;
+
+	mutex_lock(&cinode->lock_mutex);
+	list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
+		if (flock->fl_start > li->offset ||
+		    (flock->fl_start + length) <
+		    (li->offset + li->length))
+			continue;
+		if (current->tgid != li->pid)
+			continue;
+		if (cinode->can_cache_brlcks) {
+			/*
+			 * We can cache brlock requests - simply remove a lock
+			 * from the file's list.
+			 */
+			list_del(&li->llist);
+			cifs_del_lock_waiters(li);
+			kfree(li);
+			continue;
+		}
+		cur->Length = cpu_to_le64(li->length);
+		cur->Offset = cpu_to_le64(li->offset);
+		cur->Flags = cpu_to_le32(SMB2_LOCKFLAG_UNLOCK);
+		/*
+		 * We need to save a lock here to let us add it again to the
+		 * file's list if the unlock range request fails on the server.
+		 */
+		list_move(&li->llist, &tmp_llist);
+		if (++num == max_num) {
+			stored_rc = smb2_lockv(xid, tcon,
+					       cfile->fid.persistent_fid,
+					       cfile->fid.volatile_fid,
+					       current->tgid, num, buf);
+			if (stored_rc) {
+				/*
+				 * We failed on the unlock range request - add
+				 * all locks from the tmp list to the head of
+				 * the file's list.
+				 */
+				cifs_move_llist(&tmp_llist,
+						&cfile->llist->locks);
+				rc = stored_rc;
+			} else
+				/*
+				 * The unlock range request succeed - free the
+				 * tmp list.
+				 */
+				cifs_free_llist(&tmp_llist);
+			cur = buf;
+			num = 0;
+		} else
+			cur++;
+	}
+	if (num) {
+		stored_rc = smb2_lockv(xid, tcon, cfile->fid.persistent_fid,
+				       cfile->fid.volatile_fid, current->tgid,
+				       num, buf);
+		if (stored_rc) {
+			cifs_move_llist(&tmp_llist, &cfile->llist->locks);
+			rc = stored_rc;
+		} else
+			cifs_free_llist(&tmp_llist);
+	}
+	mutex_unlock(&cinode->lock_mutex);
+
+	kfree(buf);
+	return rc;
+}