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Commit 5ab56090 authored by Liu Bo's avatar Liu Bo Committed by David Sterba
Browse files

Btrfs: introduce a function to get extra mirror from replace 



As the part of getting extra mirror in __btrfs_map_block is
independent, this puts it into a separate function.

Reviewed-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: default avatarLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 0b3d4cd3

fs/btrfs/volumes.c

+89 −72
Original line number Diff line number Diff line
@@ -139,6 +139,11 @@ static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info); 
static void __btrfs_reset_dev_stats(struct btrfs_device *dev);

static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev);

static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);

static int __btrfs_map_block(struct btrfs_fs_info *fs_info,

			     enum btrfs_map_op op,

			     u64 logical, u64 *length,

			     struct btrfs_bio **bbio_ret,

			     int mirror_num, int need_raid_map);



DEFINE_MUTEX(uuid_mutex);

static LIST_HEAD(fs_uuids);
@@ -5450,6 +5455,83 @@ static int __btrfs_map_block_for_discard(struct btrfs_fs_info *fs_info, 
	return ret;

}



/*

 * In dev-replace case, for repair case (that's the only case where the mirror

 * is selected explicitly when calling btrfs_map_block), blocks left of the

 * left cursor can also be read from the target drive.

 *

 * For REQ_GET_READ_MIRRORS, the target drive is added as the last one to the

 * array of stripes.

 * For READ, it also needs to be supported using the same mirror number.

 *

 * If the requested block is not left of the left cursor, EIO is returned. This

 * can happen because btrfs_num_copies() returns one more in the dev-replace

 * case.

 */

static int get_extra_mirror_from_replace(struct btrfs_fs_info *fs_info,

					 u64 logical, u64 length,

					 u64 srcdev_devid, int *mirror_num,

					 u64 *physical)

{

	struct btrfs_bio *bbio = NULL;

	int num_stripes;

	int index_srcdev = 0;

	int found = 0;

	u64 physical_of_found = 0;

	int i;

	int ret = 0;



	ret = __btrfs_map_block(fs_info, BTRFS_MAP_GET_READ_MIRRORS,

				logical, &length, &bbio, 0, 0);

	if (ret) {

		ASSERT(bbio == NULL);

		return ret;

	}



	num_stripes = bbio->num_stripes;

	if (*mirror_num > num_stripes) {

		/*

		 * BTRFS_MAP_GET_READ_MIRRORS does not contain this mirror,

		 * that means that the requested area is not left of the left

		 * cursor

		 */

		btrfs_put_bbio(bbio);

		return -EIO;

	}



	/*

	 * process the rest of the function using the mirror_num of the source

	 * drive. Therefore look it up first.  At the end, patch the device

	 * pointer to the one of the target drive.

	 */

	for (i = 0; i < num_stripes; i++) {

		if (bbio->stripes[i].dev->devid != srcdev_devid)

			continue;



		/*

		 * In case of DUP, in order to keep it simple, only add the

		 * mirror with the lowest physical address

		 */

		if (found &&

		    physical_of_found <= bbio->stripes[i].physical)

			continue;



		index_srcdev = i;

		found = 1;

		physical_of_found = bbio->stripes[i].physical;

	}



	btrfs_put_bbio(bbio);



	ASSERT(found);

	if (!found)

		return -EIO;



	*mirror_num = index_srcdev + 1;

	*physical = physical_of_found;

	return ret;

}



static int __btrfs_map_block(struct btrfs_fs_info *fs_info,

			     enum btrfs_map_op op,

			     u64 logical, u64 *length,
@@ -5554,79 +5636,14 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, 
	if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&

	    op != BTRFS_MAP_WRITE && op != BTRFS_MAP_GET_READ_MIRRORS &&

	    dev_replace->tgtdev != NULL) {

		/*

		 * in dev-replace case, for repair case (that's the only

		 * case where the mirror is selected explicitly when

		 * calling btrfs_map_block), blocks left of the left cursor

		 * can also be read from the target drive.

		 * For REQ_GET_READ_MIRRORS, the target drive is added as

		 * the last one to the array of stripes. For READ, it also

		 * needs to be supported using the same mirror number.

		 * If the requested block is not left of the left cursor,

		 * EIO is returned. This can happen because btrfs_num_copies()

		 * returns one more in the dev-replace case.

		 */

		u64 tmp_length = *length;

		struct btrfs_bio *tmp_bbio = NULL;

		int tmp_num_stripes;

		u64 srcdev_devid = dev_replace->srcdev->devid;

		int index_srcdev = 0;

		int found = 0;

		u64 physical_of_found = 0;



		ret = __btrfs_map_block(fs_info, BTRFS_MAP_GET_READ_MIRRORS,

			     logical, &tmp_length, &tmp_bbio, 0, 0);

		if (ret) {

			WARN_ON(tmp_bbio != NULL);

			goto out;

		}



		tmp_num_stripes = tmp_bbio->num_stripes;

		if (mirror_num > tmp_num_stripes) {

			/*

			 * BTRFS_MAP_GET_READ_MIRRORS does not contain this

			 * mirror, that means that the requested area

			 * is not left of the left cursor

			 */

			ret = -EIO;

			btrfs_put_bbio(tmp_bbio);

			goto out;

		}



		/*

		 * process the rest of the function using the mirror_num

		 * of the source drive. Therefore look it up first.

		 * At the end, patch the device pointer to the one of the

		 * target drive.

		 */

		for (i = 0; i < tmp_num_stripes; i++) {

			if (tmp_bbio->stripes[i].dev->devid != srcdev_devid)

				continue;



			/*

			 * In case of DUP, in order to keep it simple, only add

			 * the mirror with the lowest physical address

			 */

			if (found &&

			    physical_of_found <= tmp_bbio->stripes[i].physical)

				continue;



			index_srcdev = i;

			found = 1;

			physical_of_found = tmp_bbio->stripes[i].physical;

		}



		btrfs_put_bbio(tmp_bbio);



		if (!found) {

			WARN_ON(1);

			ret = -EIO;

		ret = get_extra_mirror_from_replace(fs_info, logical, *length,

						    dev_replace->srcdev->devid,

						    &mirror_num,

					    &physical_to_patch_in_first_stripe);

		if (ret)

			goto out;

		}



		mirror_num = index_srcdev + 1;

		else

			patch_the_first_stripe_for_dev_replace = 1;

		physical_to_patch_in_first_stripe = physical_of_found;

	} else if (mirror_num > map->num_stripes) {

		mirror_num = 0;

	}