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Commit 3c12ac72 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Simplify device selection for mirrored reads 



Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent f2d8d74d

fs/btrfs/extent-tree.c

+4 −4
Original line number Diff line number Diff line
@@ -640,7 +640,7 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans, 
	if (!path)

		return -ENOMEM;



	path->reada = 0;

	path->reada = 1;

	key.objectid = bytenr;

	btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);

	key.offset = num_bytes;
@@ -660,7 +660,7 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans, 


	btrfs_release_path(root->fs_info->extent_root, path);



	path->reada = 0;

	path->reada = 1;

	ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,

					  path, bytenr, root_objectid,

					  ref_generation, owner, owner_offset);
@@ -692,7 +692,7 @@ static int lookup_extent_ref(struct btrfs_trans_handle *trans, 


	WARN_ON(num_bytes < root->sectorsize);

	path = btrfs_alloc_path();

	path->reada = 0;

	path->reada = 1;

	key.objectid = bytenr;

	key.offset = num_bytes;

	btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
@@ -1328,7 +1328,7 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root 
	if (!path)

		return -ENOMEM;



	path->reada = 0;

	path->reada = 1;

	ret = lookup_extent_backref(trans, extent_root, path,

				    bytenr, root_objectid,

				    ref_generation,

fs/btrfs/volumes.c

+7 −16
Original line number Diff line number Diff line
@@ -1029,19 +1029,8 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw, 
		else if (mirror_num) {

			stripe_index = mirror_num - 1;

		} else {

			int i;

			u64 least = (u64)-1;

			struct btrfs_device *cur;



			for (i = 0; i < map->num_stripes; i++) {

				cur = map->stripes[i].dev;

				spin_lock(&cur->io_lock);

				if (cur->total_ios < least) {

					least = cur->total_ios;

					stripe_index = i;

				}

				spin_unlock(&cur->io_lock);

			}

			u64 orig_stripe_nr = stripe_nr;

			stripe_index = do_div(orig_stripe_nr, num_stripes);

		}

	} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {

		if (rw & (1 << BIO_RW))
@@ -1050,7 +1039,6 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw, 
			stripe_index = mirror_num - 1;

	} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {

		int factor = map->num_stripes / map->sub_stripes;

		int orig_stripe_nr = stripe_nr;



		stripe_index = do_div(stripe_nr, factor);

		stripe_index *= map->sub_stripes;
@@ -1059,8 +1047,11 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw, 
			num_stripes = map->sub_stripes;

		else if (mirror_num)

			stripe_index += mirror_num - 1;

		else

			stripe_index += orig_stripe_nr % map->sub_stripes;

		else {

			u64 orig_stripe_nr = stripe_nr;

			stripe_index += do_div(orig_stripe_nr,

					       map->sub_stripes);

		}

	} else {

		/*

		 * after this do_div call, stripe_nr is the number of stripes