CIFS: Implement cifs_relock_file

that reacquires byte-range locks when a file is reopened.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 23 insertions, 3 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 1747cbff7ddf..67fe0b811f23 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -505,16 +505,36 @@ out:
         return rc;
 }
 
+static int cifs_push_posix_locks(struct cifsFileInfo *cfile);
+
 /*
  * Try to reacquire byte range locks that were released when session
- * to server was lost
+ * to server was lost.
  */
-static int cifs_relock_file(struct cifsFileInfo *cifsFile)
+static int
+cifs_relock_file(struct cifsFileInfo *cfile)
 {
+        struct cifs_sb_info *cifs_sb = CIFS_SB(cfile->dentry->d_sb);
+        struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
+        struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
         int rc = 0;
 
-        /* BB list all locks open on this file and relock */
+        /* we are going to update can_cache_brlcks here - need a write access */
+        down_write(&cinode->lock_sem);
+        if (cinode->can_cache_brlcks) {
+                /* can cache locks - no need to push them */
+                up_write(&cinode->lock_sem);
+                return rc;
+        }
+
+        if (cap_unix(tcon->ses) &&
+            (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
+            ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
+                rc = cifs_push_posix_locks(cfile);
+        else
+                rc = tcon->ses->server->ops->push_mand_locks(cfile);
 
+        up_write(&cinode->lock_sem);
         return rc;
 }