stale bdev reference in quotactl

@@ -799,24 +799,20 @@
 }
 
 /**
- * open_bdev_excl  -  open a block device by name and set it up for use
+ * lookup_bdev  - lookup a struct block_device by name
  *
  * @path:	special file representing the block device
- * @flags:	%MS_RDONLY for opening read-only
- * @kind:	usage (same as the 4th paramter to blkdev_get)
- * @holder:	owner for exclusion
  *
- * Open the blockdevice described by the special file at @path, claim it
- * for the @holder and properly set it up for @kind usage.
+ * Get a reference to the blockdevice at @path in the current
+ * namespace if possible and return it.  Return ERR_PTR(error)
+ * otherwise.
  */
-struct block_device *open_bdev_excl(const char *path, int flags,
-				    int kind, void *holder)
+struct block_device *lookup_bdev(const char *path)
 {
-	struct inode *inode;
 	struct block_device *bdev;
+	struct inode *inode;
 	struct nameidata nd;
-	mode_t mode = FMODE_READ;
-	int error = 0;
+	int error;
 
 	if (!path || !*path)
 		return ERR_PTR(-EINVAL);

@@ -828,17 +824,44 @@
 	inode = nd.dentry->d_inode;
 	error = -ENOTBLK;
 	if (!S_ISBLK(inode->i_mode))
-		goto path_release;
+		goto fail;
 	error = -EACCES;
 	if (nd.mnt->mnt_flags & MNT_NODEV)
-		goto path_release;
+		goto fail;
 	error = bd_acquire(inode);
 	if (error)
-		goto path_release;
+		goto fail;
 	bdev = inode->i_bdev;
 
-	/* Done with lookups */
+out:
 	path_release(&nd);
+	return bdev;
+fail:
+	bdev = ERR_PTR(error);
+	goto out;
+}
+
+/**
+ * open_bdev_excl  -  open a block device by name and set it up for use
+ *
+ * @path:	special file representing the block device
+ * @flags:	%MS_RDONLY for opening read-only
+ * @kind:	usage (same as the 4th paramter to blkdev_get)
+ * @holder:	owner for exclusion
+ *
+ * Open the blockdevice described by the special file at @path, claim it
+ * for the @holder and properly set it up for @kind usage.
+ */
+struct block_device *open_bdev_excl(const char *path, int flags,
+				    int kind, void *holder)
+{
+	struct block_device *bdev;
+	mode_t mode = FMODE_READ;
+	int error = 0;
+
+	bdev = lookup_bdev(path);
+	if (IS_ERR(bdev))
+		return bdev;
 
 	if (!(flags & MS_RDONLY))
 		mode |= FMODE_WRITE;

@@ -856,10 +879,6 @@
 	
 blkdev_put:
 	blkdev_put(bdev, BDEV_FS);
-	return ERR_PTR(error);
-
-path_release:
-	path_release(&nd);
 	return ERR_PTR(error);
 }
 

70 lines not on this page · raw message

@@ -1103,6 +1100,7 @@
 {
 	return __bdevname(bdev->bd_dev);
 }
+extern struct block_device *lookup_bdev(const char *);
 extern struct block_device *open_bdev_excl(const char *, int, int, void *);
 extern void close_bdev_excl(struct block_device *, int);