1 files changed, 68 insertions, 9 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 430e7419349c..1999533b52be 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -807,17 +807,15 @@ char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 	struct btrfs_root_ref *root_ref;
 	struct btrfs_inode_ref *inode_ref;
 	struct btrfs_key key;
-	struct btrfs_path *path = NULL;
+	BTRFS_PATH_AUTO_FREE(path);
 	char *name = NULL, *ptr;
 	u64 dirid;
 	int len;
 	int ret;
 
 	path = btrfs_alloc_path();
-	if (!path) {
-		ret = -ENOMEM;
-		goto err;
-	}
+	if (!path)
+		return ERR_PTR(-ENOMEM);
 
 	name = kmalloc(PATH_MAX, GFP_KERNEL);
 	if (!name) {
@@ -905,7 +903,6 @@ char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 		fs_root = NULL;
 	}
 
-	btrfs_free_path(path);
 	if (ptr == name + PATH_MAX - 1) {
 		name[0] = '/';
 		name[1] = '\0';
@@ -916,7 +913,6 @@ char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 
 err:
 	btrfs_put_root(fs_root);
-	btrfs_free_path(path);
 	kfree(name);
 	return ERR_PTR(ret);
 }
@@ -1614,7 +1610,7 @@ static inline void btrfs_descending_sort_devices(
 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
 					      u64 *free_bytes)
 {
-	struct btrfs_device_info *devices_info;
+	struct btrfs_device_info AUTO_KFREE(devices_info);
 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 	struct btrfs_device *device;
 	u64 type;
@@ -1712,7 +1708,6 @@ static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
 		nr_devices--;
 	}
 
-	kfree(devices_info);
 	*free_bytes = avail_space;
 	return 0;
 }
@@ -2430,6 +2425,66 @@ static long btrfs_free_cached_objects(struct super_block *sb, struct shrink_cont
 	return 0;
 }
 
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+static int btrfs_remove_bdev(struct super_block *sb, struct block_device *bdev)
+{
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	struct btrfs_device *device;
+	struct btrfs_dev_lookup_args lookup_args = { .devt = bdev->bd_dev };
+	bool can_rw;
+
+	mutex_lock(&fs_info->fs_devices->device_list_mutex);
+	device = btrfs_find_device(fs_info->fs_devices, &lookup_args);
+	if (!device) {
+		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+		/* Device not found, should not affect the running fs, just give a warning. */
+		btrfs_warn(fs_info, "unable to find btrfs device for block device '%pg'", bdev);
+		return 0;
+	}
+	/*
+	 * The to-be-removed device is already missing?
+	 *
+	 * That's weird but no special handling needed and can exit right now.
+	 */
+	if (unlikely(test_and_set_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))) {
+		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+		btrfs_warn(fs_info, "btrfs device id %llu is already missing", device->devid);
+		return 0;
+	}
+
+	device->fs_devices->missing_devices++;
+	if (test_and_clear_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state)) {
+		list_del_init(&device->dev_alloc_list);
+		WARN_ON(device->fs_devices->rw_devices < 1);
+		device->fs_devices->rw_devices--;
+	}
+	can_rw = btrfs_check_rw_degradable(fs_info, device);
+	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+	/*
+	 * Now device is considered missing, btrfs_device_name() won't give a
+	 * meaningful result anymore, so only output the devid.
+	 */
+	if (unlikely(!can_rw)) {
+		btrfs_crit(fs_info,
+		"btrfs device id %llu has gone missing, can not maintain read-write",
+			   device->devid);
+		return -EIO;
+	}
+	btrfs_warn(fs_info,
+		   "btrfs device id %llu has gone missing, continue as degraded",
+		   device->devid);
+	btrfs_set_opt(fs_info->mount_opt, DEGRADED);
+	return 0;
+}
+
+static void btrfs_shutdown(struct super_block *sb)
+{
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+
+	btrfs_force_shutdown(fs_info);
+}
+#endif
+
 static const struct super_operations btrfs_super_ops = {
 	.drop_inode	= btrfs_drop_inode,
 	.evict_inode	= btrfs_evict_inode,
@@ -2445,6 +2500,10 @@ static const struct super_operations btrfs_super_ops = {
 	.unfreeze_fs	= btrfs_unfreeze,
 	.nr_cached_objects = btrfs_nr_cached_objects,
 	.free_cached_objects = btrfs_free_cached_objects,
+#ifdef CONFIG_BTRFS_EXPERIMENTAL
+	.remove_bdev	= btrfs_remove_bdev,
+	.shutdown	= btrfs_shutdown,
+#endif
 };
 
 static const struct file_operations btrfs_ctl_fops = {