[CIFS] Fix paths when share is in DFS to include proper prefix

Some versions of Samba (3.2-pre e.g.) are stricter about checking to make sure that
paths in DFS name spaces are sent in the form \\server\share\dir\subdir ...
instead of \dir\subdir

Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 23 insertions, 5 deletions

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index e4e0078a0526..05afe33ea644 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -49,18 +49,25 @@ build_path_from_dentry(struct dentry *direntry)
         struct dentry *temp;
         int namelen;
         int pplen;
+        int dfsplen;
         char *full_path;
         char dirsep;
+        struct cifs_sb_info *cifs_sb;
 
         if (direntry == NULL)
                 return NULL;  /* not much we can do if dentry is freed and
                 we need to reopen the file after it was closed implicitly
                 when the server crashed */
 
-        dirsep = CIFS_DIR_SEP(CIFS_SB(direntry->d_sb));
-        pplen = CIFS_SB(direntry->d_sb)->prepathlen;
+        cifs_sb = CIFS_SB(direntry->d_sb);
+        dirsep = CIFS_DIR_SEP(cifs_sb);
+        pplen = cifs_sb->prepathlen;
+        if (cifs_sb->tcon && (cifs_sb->tcon->Flags & SMB_SHARE_IS_IN_DFS))
+                dfsplen = strnlen(cifs_sb->tcon->treeName, MAX_TREE_SIZE + 1);
+        else
+                dfsplen = 0;
 cifs_bp_rename_retry:
-        namelen = pplen;
+        namelen = pplen + dfsplen;
         for (temp = direntry; !IS_ROOT(temp);) {
                 namelen += (1 + temp->d_name.len);
                 temp = temp->d_parent;
@@ -91,7 +98,7 @@ cifs_bp_rename_retry:
                         return NULL;
                 }
         }
-        if (namelen != pplen) {
+        if (namelen != pplen + dfsplen) {
                 cERROR(1,
                        ("did not end path lookup where expected namelen is %d",
                         namelen));
@@ -107,7 +114,18 @@ cifs_bp_rename_retry:
            since the '\' is a valid posix character so we can not switch
            those safely to '/' if any are found in the middle of the prepath */
         /* BB test paths to Windows with '/' in the midst of prepath */
-        strncpy(full_path, CIFS_SB(direntry->d_sb)->prepath, pplen);
+
+        if (dfsplen) {
+                strncpy(full_path, cifs_sb->tcon->treeName, dfsplen);
+                if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) {
+                        int i;
+                        for (i = 0; i < dfsplen; i++) {
+                                if (full_path[i] == '\\')
+                                        full_path[i] = '/';
+                        }
+                }
+        }
+        strncpy(full_path + dfsplen, CIFS_SB(direntry->d_sb)->prepath, pplen);
         return full_path;
 }