cifs_get_root shouldn't use path with tree name

When a server returns the optional flag SMB_SHARE_IS_IN_DFS in response
to a tree connect, cifs_build_path_to_root() will return a pathname
which includes the hostname. This causes problems with cifs_get_root()
which separates each component and does a lookup for each component of
the path which in this case will incorrectly include looking up the
hostname component as a path component.

We encountered a problem with dfs shares hosted by a Netapp. When
connecting to nodes pointed to by the DFS share. The tree connect for
these nodes return SMB_SHARE_IS_IN_DFS resulting failures in lookup
in cifs_get_root().

RH bz: 1373153
The patch was tested against a Netapp simulator and by a user using an
actual Netapp server.

Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reported-by: Pierguido Lambri <plambri@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 15261ba464c5023f82014751fee8efaf09abec5f..f135f088cdff52ab15cfceffc25e208b5eebe93d 100644 (file)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -615,7 +615,7 @@ cifs_get_root(struct smb_vol *vol, struct super_block *sb)
                return dget(sb->s_root);
 
        full_path = cifs_build_path_to_root(vol, cifs_sb,
-                                           cifs_sb_master_tcon(cifs_sb));
+                               cifs_sb_master_tcon(cifs_sb), 0);
        if (full_path == NULL)
                return ERR_PTR(-ENOMEM);
 

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index cd8025a249bba990170e23d9ae6406e134ebdff2..c7b3c841e6604d150e22d2ed40695c2cec3d3d99 100644 (file)
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -63,7 +63,8 @@ extern void exit_cifs_spnego(void);
 extern char *build_path_from_dentry(struct dentry *);
 extern char *cifs_build_path_to_root(struct smb_vol *vol,
                                     struct cifs_sb_info *cifs_sb,
-                                    struct cifs_tcon *tcon);
+                                    struct cifs_tcon *tcon,
+                                    int add_treename);
 extern char *build_wildcard_path_from_dentry(struct dentry *direntry);
 extern char *cifs_compose_mount_options(const char *sb_mountdata,
                const char *fullpath, const struct dfs_info3_param *ref,

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 1847aa8390ff0753628791ddf6d676746d9df210..851256e99cf0f9ac3dc75a5f69cdb199731ab216 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3765,7 +3765,8 @@ remote_path_check:
                /*
                 * cifs_build_path_to_root works only when we have a valid tcon
                 */
-               full_path = cifs_build_path_to_root(volume_info, cifs_sb, tcon);
+               full_path = cifs_build_path_to_root(volume_info, cifs_sb, tcon,
+                                       tcon->Flags & SMB_SHARE_IS_IN_DFS);
                if (full_path == NULL) {
                        rc = -ENOMEM;
                        goto mount_fail_check;

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 789ff1df2d8d5d1b6b923ee1f60428278a9d0319..2c227a99f369f08e8941652eb87dd685a6f66b61 100644 (file)
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -47,7 +47,7 @@ renew_parental_timestamps(struct dentry *direntry)
 
 char *
 cifs_build_path_to_root(struct smb_vol *vol, struct cifs_sb_info *cifs_sb,
-                       struct cifs_tcon *tcon)
+                       struct cifs_tcon *tcon, int add_treename)
 {
        int pplen = vol->prepath ? strlen(vol->prepath) + 1 : 0;
        int dfsplen;
@@ -59,7 +59,7 @@ cifs_build_path_to_root(struct smb_vol *vol, struct cifs_sb_info *cifs_sb,
                return full_path;
        }
 
-       if (tcon->Flags & SMB_SHARE_IS_IN_DFS)
+       if (add_treename)
                dfsplen = strnlen(tcon->treeName, MAX_TREE_SIZE + 1);
        else
                dfsplen = 0;