[CIFS] Allow disabling CIFS Unix Extensions as mount option

Previously the only way to do this was to umount all mounts to that server,
turn off a proc setting (/proc/fs/cifs/LinuxExtensionsEnabled).

Fixes Samba bugzilla bug number: 4582 (and also 2008)

Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 12 insertions, 5 deletions

diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 7da755c6550a..6a85ef7b8797 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -55,7 +55,8 @@ cifs_hardlink(struct dentry *old_file, struct inode *inode,
                 goto cifs_hl_exit;
         }
 
-        if (cifs_sb_target->tcon->ses->capabilities & CAP_UNIX)
+/*      if (cifs_sb_target->tcon->ses->capabilities & CAP_UNIX)*/
+        if (pTcon->unix_ext)
                 rc = CIFSUnixCreateHardLink(xid, pTcon, fromName, toName,
                                             cifs_sb_target->local_nls,
                                             cifs_sb_target->mnt_cifs_flags &
@@ -129,14 +130,19 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
                 goto out;
         }
 
-        /* BB add read reparse point symlink code and Unix extensions
-           symlink code here BB */
+        /* We could change this to:
+                if (pTcon->unix_ext)
+           but there does not seem any point in refusing to
+           get symlink info if we can, even if unix extensions
+           turned off for this mount */
+
         if (pTcon->ses->capabilities & CAP_UNIX)
                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
                                              target_path,
                                              PATH_MAX-1,
                                              cifs_sb->local_nls);
         else {
+                /* BB add read reparse point symlink code here */
                 /* rc = CIFSSMBQueryReparseLinkInfo */
                 /* BB Add code to Query ReparsePoint info */
                 /* BB Add MAC style xsymlink check here if enabled */
@@ -186,7 +192,7 @@ 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 (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
+        if (pTcon->unix_ext)
                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
                                            cifs_sb->local_nls);
         /* else
@@ -194,7 +200,7 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
                                         cifs_sb_target->local_nls); */
 
         if (rc == 0) {
-                if (pTcon->ses->capabilities & CAP_UNIX)
+                if (pTcon->unix_ext)
                         rc = cifs_get_inode_info_unix(&newinode, full_path,
                                                       inode->i_sb, xid);
                 else
@@ -266,6 +272,7 @@ cifs_readlink(struct dentry *direntry, char __user *pBuffer, int buflen)
 
 /* BB add read reparse point symlink code and
         Unix extensions symlink code here BB */
+/* We could disable this based on pTcon->unix_ext flag instead ... but why? */
         if (cifs_sb->tcon->ses->capabilities & CAP_UNIX)
                 rc = CIFSSMBUnixQuerySymLink(xid, pTcon, full_path,
                                 tmpbuffer,