cifs: use Minshall+French symlink functions

If configured, Minshall+French Symlinks are used against
all servers. If the server supports UNIX Extensions,
we still create Minshall+French Symlinks on write,
but on read we fallback to UNIX Extension symlinks.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 23 insertions, 4 deletions

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 1b2a8c971995..cbf7b112287b 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -407,7 +407,8 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
          * but there doesn't seem to be any harm in allowing the client to
          * read them.
          */
-        if (!(tcon->ses->capabilities & CAP_UNIX)) {
+        if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+            && !(tcon->ses->capabilities & CAP_UNIX)) {
                 rc = -EACCES;
                 goto out;
         }
@@ -418,8 +419,21 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 
         cFYI(1, "Full path: %s inode = 0x%p", full_path, inode);
 
-        rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
-                                     cifs_sb->local_nls);
+        rc = -EACCES;
+        /*
+         * First try Minshall+French Symlinks, if configured
+         * and fallback to UNIX Extensions Symlinks.
+         */
+        if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+                rc = CIFSQueryMFSymLink(xid, tcon, full_path, &target_path,
+                                        cifs_sb->local_nls,
+                                        cifs_sb->mnt_cifs_flags &
+                                                CIFS_MOUNT_MAP_SPECIAL_CHR);
+
+        if ((rc != 0) && (tcon->ses->capabilities & CAP_UNIX))
+                rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
+                                             cifs_sb->local_nls);
+
         kfree(full_path);
 out:
         if (rc != 0) {
@@ -459,7 +473,12 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
         cFYI(1, "symname is %s", symname);
 
         /* BB what if DFS and this volume is on different share? BB */
-        if (pTcon->unix_ext)
+        if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+                rc = CIFSCreateMFSymLink(xid, pTcon, full_path, symname,
+                                         cifs_sb->local_nls,
+                                         cifs_sb->mnt_cifs_flags &
+                                                CIFS_MOUNT_MAP_SPECIAL_CHR);
+        else if (pTcon->unix_ext)
                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
                                            cifs_sb->local_nls);
         /* else