1 files changed, 19 insertions, 9 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 9802345df5e7..9e425e7e6c8f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -812,6 +812,11 @@ static int follow_automount(struct path *path, unsigned flags,
 	if (!mnt) /* mount collision */
 		return 0;
 
+	if (!*need_mntput) {
+		/* lock_mount() may release path->mnt on error */
+		mntget(path->mnt);
+		*need_mntput = true;
+	}
 	err = finish_automount(mnt, path);
 
 	switch (err) {
@@ -819,12 +824,9 @@ static int follow_automount(struct path *path, unsigned flags,
 		/* Someone else made a mount here whilst we were busy */
 		return 0;
 	case 0:
-		dput(path->dentry);
-		if (*need_mntput)
-			mntput(path->mnt);
+		path_put(path);
 		path->mnt = mnt;
 		path->dentry = dget(mnt->mnt_root);
-		*need_mntput = true;
 		return 0;
 	default:
 		return err;
@@ -844,9 +846,10 @@ static int follow_automount(struct path *path, unsigned flags,
  */
 static int follow_managed(struct path *path, unsigned flags)
 {
+	struct vfsmount *mnt = path->mnt; /* held by caller, must be left alone */
 	unsigned managed;
 	bool need_mntput = false;
-	int ret;
+	int ret = 0;
 
 	/* Given that we're not holding a lock here, we retain the value in a
 	 * local variable for each dentry as we look at it so that we don't see
@@ -861,7 +864,7 @@ static int follow_managed(struct path *path, unsigned flags)
 			BUG_ON(!path->dentry->d_op->d_manage);
 			ret = path->dentry->d_op->d_manage(path->dentry, false);
 			if (ret < 0)
-				return ret == -EISDIR ? 0 : ret;
+				break;
 		}
 
 		/* Transit to a mounted filesystem. */
@@ -887,14 +890,19 @@ static int follow_managed(struct path *path, unsigned flags)
 		if (managed & DCACHE_NEED_AUTOMOUNT) {
 			ret = follow_automount(path, flags, &need_mntput);
 			if (ret < 0)
-				return ret == -EISDIR ? 0 : ret;
+				break;
 			continue;
 		}
 
 		/* We didn't change the current path point */
 		break;
 	}
-	return 0;
+
+	if (need_mntput && path->mnt == mnt)
+		mntput(path->mnt);
+	if (ret == -EISDIR)
+		ret = 0;
+	return ret;
 }
 
 int follow_down_one(struct path *path)
@@ -2713,8 +2721,10 @@ static long do_unlinkat(int dfd, const char __user *pathname)
 	error = PTR_ERR(dentry);
 	if (!IS_ERR(dentry)) {
 		/* Why not before? Because we want correct error value */
+		if (nd.last.name[nd.last.len])
+			goto slashes;
 		inode = dentry->d_inode;
-		if (nd.last.name[nd.last.len] || !inode)
+		if (!inode)
 			goto slashes;
 		ihold(inode);
 		error = mnt_want_write(nd.path.mnt);