CIFS: Reconnect durable handles for SMB2

On reconnects, we need to reopen file and then obtain all byte-range
locks held by the client. SMB2 protocol provides feature to make
this process atomic by reconnecting to the same file handle
with all it's byte-range locks. This patch adds this capability
for SMB2 shares.

Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steven French <steven@steven-GA-970A-DS3.(none)>

1 files changed, 9 insertions, 6 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index f36f9a7893da..ba7eed2ee662 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -232,6 +232,7 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
         oparms.disposition = disposition;
         oparms.path = full_path;
         oparms.fid = fid;
+        oparms.reconnect = false;
 
         rc = server->ops->open(xid, &oparms, oplock, buf);
 
@@ -594,7 +595,6 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
         int desired_access;
         int disposition = FILE_OPEN;
         int create_options = CREATE_NOT_DIR;
-        struct cifs_fid fid;
         struct cifs_open_parms oparms;
 
         xid = get_xid();
@@ -645,7 +645,7 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 
                 rc = cifs_posix_open(full_path, NULL, inode->i_sb,
                                      cifs_sb->mnt_file_mode /* ignored */,
-                                     oflags, &oplock, &fid.netfid, xid);
+                                     oflags, &oplock, &cfile->fid.netfid, xid);
                 if (rc == 0) {
                         cifs_dbg(FYI, "posix reopen succeeded\n");
                         goto reopen_success;
@@ -662,7 +662,7 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
                 create_options |= CREATE_OPEN_BACKUP_INTENT;
 
         if (server->ops->get_lease_key)
-                server->ops->get_lease_key(inode, &fid);
+                server->ops->get_lease_key(inode, &cfile->fid);
 
         oparms.tcon = tcon;
         oparms.cifs_sb = cifs_sb;
@@ -670,7 +670,8 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
         oparms.create_options = create_options;
         oparms.disposition = disposition;
         oparms.path = full_path;
-        oparms.fid = &fid;
+        oparms.fid = &cfile->fid;
+        oparms.reconnect = true;
 
         /*
          * Can not refresh inode by passing in file_info buf to be returned by
@@ -710,8 +711,9 @@ reopen_success:
          * to the server to get the new inode info.
          */
 
-        server->ops->set_fid(cfile, &fid, oplock);
-        cifs_relock_file(cfile);
+        server->ops->set_fid(cfile, &cfile->fid, oplock);
+        if (oparms.reconnect)
+                cifs_relock_file(cfile);
 
 reopen_error_exit:
         kfree(full_path);
@@ -1508,6 +1510,7 @@ cifs_setlk(struct file *file, struct file_lock *flock, __u32 type,
                 if (!rc)
                         goto out;
 
+
                 /*
                  * Windows 7 server can delay breaking lease from read to None
                  * if we set a byte-range lock on a file - break it explicitly