Commit faa775c4 authored by Josef Bacik's avatar Josef Bacik Committed by David Sterba
Browse files

btrfs: add a btrfs_get_dev_args_from_path helper 



We are going to want to populate our device lookup args outside of any
locks and then do the actual device lookup later, so add a helper to do
this work and make btrfs_find_device_by_devspec() use this helper for
now.

Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Reviewed-by: default avatarAnand Jain <anand.jain@oracle.com>
Signed-off-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 562d7b15

fs/btrfs/volumes.c

+64 −32
Original line number Diff line number Diff line
@@ -2325,45 +2325,81 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_device *tgtdev) 
	btrfs_free_device(tgtdev);

}



static struct btrfs_device *btrfs_find_device_by_path(

		struct btrfs_fs_info *fs_info, const char *device_path)

/**

 * Populate args from device at path

 *

 * @fs_info:	the filesystem

 * @args:	the args to populate

 * @path:	the path to the device

 *

 * This will read the super block of the device at @path and populate @args with

 * the devid, fsid, and uuid.  This is meant to be used for ioctls that need to

 * lookup a device to operate on, but need to do it before we take any locks.

 * This properly handles the special case of "missing" that a user may pass in,

 * and does some basic sanity checks.  The caller must make sure that @path is

 * properly NUL terminated before calling in, and must call

 * btrfs_put_dev_args_from_path() in order to free up the temporary fsid and

 * uuid buffers.

 *

 * Return: 0 for success, -errno for failure

 */

int btrfs_get_dev_args_from_path(struct btrfs_fs_info *fs_info,

				 struct btrfs_dev_lookup_args *args,

				 const char *path)

{

	BTRFS_DEV_LOOKUP_ARGS(args);

	int ret = 0;

	struct btrfs_super_block *disk_super;

	struct block_device *bdev;

	struct btrfs_device *device;

	int ret;



	ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,

				    fs_info->bdev_holder, 0, &bdev, &disk_super);

	if (ret)

		return ERR_PTR(ret);

	if (!path || !path[0])

		return -EINVAL;

	if (!strcmp(path, "missing")) {

		args->missing = true;

		return 0;

	}



	args.devid = btrfs_stack_device_id(&disk_super->dev_item);

	args.uuid = disk_super->dev_item.uuid;

	args->uuid = kzalloc(BTRFS_UUID_SIZE, GFP_KERNEL);

	args->fsid = kzalloc(BTRFS_FSID_SIZE, GFP_KERNEL);

	if (!args->uuid || !args->fsid) {

		btrfs_put_dev_args_from_path(args);

		return -ENOMEM;

	}



	ret = btrfs_get_bdev_and_sb(path, FMODE_READ, fs_info->bdev_holder, 0,

				    &bdev, &disk_super);

	if (ret)

		return ret;

	args->devid = btrfs_stack_device_id(&disk_super->dev_item);

	memcpy(args->uuid, disk_super->dev_item.uuid, BTRFS_UUID_SIZE);

	if (btrfs_fs_incompat(fs_info, METADATA_UUID))

		args.fsid = disk_super->metadata_uuid;

		memcpy(args->fsid, disk_super->metadata_uuid, BTRFS_FSID_SIZE);

	else

		args.fsid = disk_super->fsid;



	device = btrfs_find_device(fs_info->fs_devices, &args);



		memcpy(args->fsid, disk_super->fsid, BTRFS_FSID_SIZE);

	btrfs_release_disk_super(disk_super);

	if (!device)

		device = ERR_PTR(-ENOENT);

	blkdev_put(bdev, FMODE_READ);

	return device;

	return 0;

}



/*

 * Lookup a device given by device id, or the path if the id is 0.

 * Only use this jointly with btrfs_get_dev_args_from_path() because we will

 * allocate our ->uuid and ->fsid pointers, everybody else uses local variables

 * that don't need to be freed.

 */

void btrfs_put_dev_args_from_path(struct btrfs_dev_lookup_args *args)

{

	kfree(args->uuid);

	kfree(args->fsid);

	args->uuid = NULL;

	args->fsid = NULL;

}



struct btrfs_device *btrfs_find_device_by_devspec(

		struct btrfs_fs_info *fs_info, u64 devid,

		const char *device_path)

{

	BTRFS_DEV_LOOKUP_ARGS(args);

	struct btrfs_device *device;

	int ret;



	if (devid) {

		args.devid = devid;
@@ -2373,20 +2409,16 @@ struct btrfs_device *btrfs_find_device_by_devspec( 
		return device;

	}



	if (!device_path || !device_path[0])

		return ERR_PTR(-EINVAL);



	if (strcmp(device_path, "missing") == 0) {

		args.missing = true;

	ret = btrfs_get_dev_args_from_path(fs_info, &args, device_path);

	if (ret)

		return ERR_PTR(ret);

	device = btrfs_find_device(fs_info->fs_devices, &args);

	btrfs_put_dev_args_from_path(&args);

	if (!device)

		return ERR_PTR(-ENOENT);

	return device;

}



	return btrfs_find_device_by_path(fs_info, device_path);

}



/*

 * does all the dirty work required for changing file system's UUID.

 */

fs/btrfs/volumes.h

+4 −0
Original line number Diff line number Diff line
@@ -520,9 +520,13 @@ void btrfs_assign_next_active_device(struct btrfs_device *device, 
struct btrfs_device *btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info,

						  u64 devid,

						  const char *devpath);

int btrfs_get_dev_args_from_path(struct btrfs_fs_info *fs_info,

				 struct btrfs_dev_lookup_args *args,

				 const char *path);

struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,

					const u64 *devid,

					const u8 *uuid);

void btrfs_put_dev_args_from_path(struct btrfs_dev_lookup_args *args);

void btrfs_free_device(struct btrfs_device *device);

int btrfs_rm_device(struct btrfs_fs_info *fs_info,

		    const char *device_path, u64 devid,