1 files changed, 64 insertions, 78 deletions

diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
index d6ced7aa23cf..8d8f28c94c0f 100644
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -44,8 +44,7 @@ static void cifs_dfs_expire_automounts(struct work_struct *work)
 void cifs_dfs_release_automount_timer(void)
 {
         BUG_ON(!list_empty(&cifs_dfs_automount_list));
-        cancel_delayed_work(&cifs_dfs_automount_task);
-        flush_scheduled_work();
+        cancel_delayed_work_sync(&cifs_dfs_automount_task);
 }
 
 /**
@@ -54,7 +53,7 @@ void cifs_dfs_release_automount_timer(void)
  *
  * Extracts sharename form full UNC.
  * i.e. strips from UNC trailing path that is not part of share
- * name and fixup missing '\' in the begining of DFS node refferal
+ * name and fixup missing '\' in the beginning of DFS node refferal
  * if necessary.
  * Returns pointer to share name on success or ERR_PTR on error.
  * Caller is responsible for freeing returned string.
@@ -256,35 +255,6 @@ static struct vfsmount *cifs_dfs_do_refmount(struct cifs_sb_info *cifs_sb,
 
 }
 
-static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd,
-                                struct list_head *mntlist)
-{
-        /* stolen from afs code */
-        int err;
-
-        mntget(newmnt);
-        err = do_add_mount(newmnt, &nd->path, nd->path.mnt->mnt_flags | MNT_SHRINKABLE, mntlist);
-        switch (err) {
-        case 0:
-                path_put(&nd->path);
-                nd->path.mnt = newmnt;
-                nd->path.dentry = dget(newmnt->mnt_root);
-                schedule_delayed_work(&cifs_dfs_automount_task,
-                                      cifs_dfs_mountpoint_expiry_timeout);
-                break;
-        case -EBUSY:
-                /* someone else made a mount here whilst we were busy */
-                while (d_mountpoint(nd->path.dentry) &&
-                       follow_down(&nd->path))
-                        ;
-                err = 0;
-        default:
-                mntput(newmnt);
-                break;
-        }
-        return err;
-}
-
 static void dump_referral(const struct dfs_info3_param *ref)
 {
         cFYI(1, "DFS: ref path: %s", ref->path_name);
@@ -294,34 +264,23 @@ static void dump_referral(const struct dfs_info3_param *ref)
                                 ref->path_consumed);
 }
 
-
-static void*
-cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
+/*
+ * Create a vfsmount that we can automount
+ */
+static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
 {
         struct dfs_info3_param *referrals = NULL;
         unsigned int num_referrals = 0;
         struct cifs_sb_info *cifs_sb;
-        struct cifsSesInfo *ses;
-        char *full_path = NULL;
+        struct cifs_ses *ses;
+        char *full_path;
         int xid, i;
-        int rc = 0;
-        struct vfsmount *mnt = ERR_PTR(-ENOENT);
+        int rc;
+        struct vfsmount *mnt;
+        struct tcon_link *tlink;
 
         cFYI(1, "in %s", __func__);
-        BUG_ON(IS_ROOT(dentry));
-
-        xid = GetXid();
-
-        dput(nd->path.dentry);
-        nd->path.dentry = dget(dentry);
-
-        cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
-        ses = cifs_sb->tcon->ses;
-
-        if (!ses) {
-                rc = -EINVAL;
-                goto out_err;
-        }
+        BUG_ON(IS_ROOT(mntpt));
 
         /*
          * The MSDFS spec states that paths in DFS referral requests and
@@ -329,56 +288,83 @@ cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
          * the double backslashes usually used in the UNC. This function
          * gives us the latter, so we must adjust the result.
          */
-        full_path = build_path_from_dentry(dentry);
-        if (full_path == NULL) {
-                rc = -ENOMEM;
-                goto out_err;
+        mnt = ERR_PTR(-ENOMEM);
+        full_path = build_path_from_dentry(mntpt);
+        if (full_path == NULL)
+                goto cdda_exit;
+
+        cifs_sb = CIFS_SB(mntpt->d_inode->i_sb);
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink)) {
+                mnt = ERR_CAST(tlink);
+                goto free_full_path;
         }
+        ses = tlink_tcon(tlink)->ses;
 
-        rc = get_dfs_path(xid, ses , full_path + 1, cifs_sb->local_nls,
+        xid = GetXid();
+        rc = get_dfs_path(xid, ses, full_path + 1, cifs_sb->local_nls,
                 &num_referrals, &referrals,
                 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
+        FreeXid(xid);
+
+        cifs_put_tlink(tlink);
 
+        mnt = ERR_PTR(-ENOENT);
         for (i = 0; i < num_referrals; i++) {
                 int len;
-                dump_referral(referrals+i);
+                dump_referral(referrals + i);
                 /* connect to a node */
                 len = strlen(referrals[i].node_name);
                 if (len < 2) {
                         cERROR(1, "%s: Net Address path too short: %s",
                                         __func__, referrals[i].node_name);
-                        rc = -EINVAL;
-                        goto out_err;
+                        mnt = ERR_PTR(-EINVAL);
+                        break;
                 }
                 mnt = cifs_dfs_do_refmount(cifs_sb,
                                 full_path, referrals + i);
                 cFYI(1, "%s: cifs_dfs_do_refmount:%s , mnt:%p", __func__,
                                         referrals[i].node_name, mnt);
-
-                /* complete mount procedure if we accured submount */
                 if (!IS_ERR(mnt))
-                        break;
+                        goto success;
         }
 
-        /* we need it cause for() above could exit without valid submount */
-        rc = PTR_ERR(mnt);
-        if (IS_ERR(mnt))
-                goto out_err;
+        /* no valid submounts were found; return error from get_dfs_path() by
+         * preference */
+        if (rc != 0)
+                mnt = ERR_PTR(rc);
 
-        rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);
-
-out:
-        FreeXid(xid);
+success:
         free_dfs_info_array(referrals, num_referrals);
+free_full_path:
         kfree(full_path);
+cdda_exit:
         cFYI(1, "leaving %s" , __func__);
-        return ERR_PTR(rc);
-out_err:
-        path_put(&nd->path);
-        goto out;
+        return mnt;
+}
+
+/*
+ * Attempt to automount the referral
+ */
+struct vfsmount *cifs_dfs_d_automount(struct path *path)
+{
+        struct vfsmount *newmnt;
+
+        cFYI(1, "in %s", __func__);
+
+        newmnt = cifs_dfs_do_automount(path->dentry);
+        if (IS_ERR(newmnt)) {
+                cFYI(1, "leaving %s [automount failed]" , __func__);
+                return newmnt;
+        }
+
+        mntget(newmnt); /* prevent immediate expiration */
+        mnt_set_expiry(newmnt, &cifs_dfs_automount_list);
+        schedule_delayed_work(&cifs_dfs_automount_task,
+                              cifs_dfs_mountpoint_expiry_timeout);
+        cFYI(1, "leaving %s [ok]" , __func__);
+        return newmnt;
 }
 
 const struct inode_operations cifs_dfs_referral_inode_operations = {
-        .follow_link = cifs_dfs_follow_mountpoint,
 };
-