4 files changed, 66 insertions, 70 deletions

diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
index c68a056f27fd..7ed36536e754 100644
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -255,35 +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);
@@ -293,45 +264,43 @@ 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;
+        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));
+        BUG_ON(IS_ROOT(mntpt));
 
         xid = GetXid();
 
-        dput(nd->path.dentry);
-        nd->path.dentry = dget(dentry);
-
         /*
          * The MSDFS spec states that paths in DFS referral requests and
          * responses must be prefixed by a single '\' character instead of
          * 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 free_xid;
 
-        cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
+        cifs_sb = CIFS_SB(mntpt->d_inode->i_sb);
         tlink = cifs_sb_tlink(cifs_sb);
+        mnt = ERR_PTR(-EINVAL);
         if (IS_ERR(tlink)) {
-                rc = PTR_ERR(tlink);
-                goto out_err;
+                mnt = ERR_CAST(tlink);
+                goto free_full_path;
         }
         ses = tlink_tcon(tlink)->ses;
 
@@ -341,46 +310,63 @@ cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
 
         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;
-
-        rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);
+        /* no valid submounts were found; return error from get_dfs_path() by
+         * preference */
+        if (rc != 0)
+                mnt = ERR_PTR(rc);
 
-out:
-        FreeXid(xid);
+success:
         free_dfs_info_array(referrals, num_referrals);
+free_full_path:
         kfree(full_path);
+free_xid:
+        FreeXid(xid);
         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,
 };
-
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 897b2b2b28b5..851030f74939 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -93,6 +93,12 @@ extern int cifs_readdir(struct file *file, void *direntry, filldir_t filldir);
 extern const struct dentry_operations cifs_dentry_ops;
 extern const struct dentry_operations cifs_ci_dentry_ops;
 
+#ifdef CONFIG_CIFS_DFS_UPCALL
+extern struct vfsmount *cifs_dfs_d_automount(struct path *path);
+#else
+#define cifs_dfs_d_automount NULL
+#endif
+
 /* Functions related to symlinks */
 extern void *cifs_follow_link(struct dentry *direntry, struct nameidata *nd);
 extern void cifs_put_link(struct dentry *direntry,
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 1e95dd635632..dd5f22918c33 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -675,6 +675,7 @@ cifs_d_revalidate(struct dentry *direntry, struct nameidata *nd)
 
 const struct dentry_operations cifs_dentry_ops = {
         .d_revalidate = cifs_d_revalidate,
+        .d_automount = cifs_dfs_d_automount,
 /* d_delete:       cifs_d_delete,      */ /* not needed except for debugging */
 };
 
@@ -711,4 +712,5 @@ const struct dentry_operations cifs_ci_dentry_ops = {
         .d_revalidate = cifs_d_revalidate,
         .d_hash = cifs_ci_hash,
         .d_compare = cifs_ci_compare,
+        .d_automount = cifs_dfs_d_automount,
 };
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index b06b60620240..6c9ee8014ff0 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -32,7 +32,7 @@
 #include "fscache.h"
 
 
-static void cifs_set_ops(struct inode *inode, const bool is_dfs_referral)
+static void cifs_set_ops(struct inode *inode)
 {
         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 
@@ -60,7 +60,7 @@ static void cifs_set_ops(struct inode *inode, const bool is_dfs_referral)
                 break;
         case S_IFDIR:
 #ifdef CONFIG_CIFS_DFS_UPCALL
-                if (is_dfs_referral) {
+                if (IS_AUTOMOUNT(inode)) {
                         inode->i_op = &cifs_dfs_referral_inode_operations;
                 } else {
 #else /* NO DFS support, treat as a directory */
@@ -167,7 +167,9 @@ cifs_fattr_to_inode(struct inode *inode, struct cifs_fattr *fattr)
         }
         spin_unlock(&inode->i_lock);
 
-        cifs_set_ops(inode, fattr->cf_flags & CIFS_FATTR_DFS_REFERRAL);
+        if (fattr->cf_flags & CIFS_FATTR_DFS_REFERRAL)
+                inode->i_flags |= S_AUTOMOUNT;
+        cifs_set_ops(inode);
 }
 
 void