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Commit 9c6d173e authored by Anand Jain's avatar Anand Jain Committed by David Sterba
Browse files

btrfs: extend locked section when adding a new device in device_list_add 



Make sure the device_list_lock is held the whole time:

* when the device is being looked up
* new device is initialized and put to the list
* the list counters are updated (fs_devices::opened, fs_devices::total_devices)

Signed-off-by: default avatarAnand Jain <anand.jain@oracle.com>
[ update changelog ]
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 4306a974

fs/btrfs/volumes.c

+12 −4
Original line number Diff line number Diff line
@@ -762,21 +762,26 @@ static noinline struct btrfs_device *device_list_add(const char *path, 
		if (IS_ERR(fs_devices))

			return ERR_CAST(fs_devices);



		mutex_lock(&fs_devices->device_list_mutex);

		list_add(&fs_devices->fs_list, &fs_uuids);



		device = NULL;

	} else {

		mutex_lock(&fs_devices->device_list_mutex);

		device = find_device(fs_devices, devid,

				disk_super->dev_item.uuid);

	}



	if (!device) {

		if (fs_devices->opened)

		if (fs_devices->opened) {

			mutex_unlock(&fs_devices->device_list_mutex);

			return ERR_PTR(-EBUSY);

		}



		device = btrfs_alloc_device(NULL, &devid,

					    disk_super->dev_item.uuid);

		if (IS_ERR(device)) {

			mutex_unlock(&fs_devices->device_list_mutex);

			/* we can safely leave the fs_devices entry around */

			return device;

		}
@@ -784,14 +789,13 @@ static noinline struct btrfs_device *device_list_add(const char *path, 
		name = rcu_string_strdup(path, GFP_NOFS);

		if (!name) {

			btrfs_free_device(device);

			mutex_unlock(&fs_devices->device_list_mutex);

			return ERR_PTR(-ENOMEM);

		}

		rcu_assign_pointer(device->name, name);



		mutex_lock(&fs_devices->device_list_mutex);

		list_add_rcu(&device->dev_list, &fs_devices->devices);

		fs_devices->num_devices++;

		mutex_unlock(&fs_devices->device_list_mutex);



		device->fs_devices = fs_devices;

		*new_device_added = true;
@@ -838,12 +842,15 @@ static noinline struct btrfs_device *device_list_add(const char *path, 
			 * with larger generation number or the last-in if

			 * generation are equal.

			 */

			mutex_unlock(&fs_devices->device_list_mutex);

			return ERR_PTR(-EEXIST);

		}



		name = rcu_string_strdup(path, GFP_NOFS);

		if (!name)

		if (!name) {

			mutex_unlock(&fs_devices->device_list_mutex);

			return ERR_PTR(-ENOMEM);

		}

		rcu_string_free(device->name);

		rcu_assign_pointer(device->name, name);

		if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state)) {
@@ -863,6 +870,7 @@ static noinline struct btrfs_device *device_list_add(const char *path, 


	fs_devices->total_devices = btrfs_super_num_devices(disk_super);



	mutex_unlock(&fs_devices->device_list_mutex);

	return device;

}