Commit 0f96f517 authored by Robbie Ko's avatar Robbie Ko Committed by David Sterba
Browse files

btrfs: incremental send, improve rmdir performance for large directory 



Currently when checking if a directory can be deleted, we always check
if all its children have been processed.

Example: A directory with 2,000,000 files was deleted

original: 1994m57.071s
patch:       1m38.554s

[FIX]
Instead of checking all children on all calls to can_rmdir(), we keep
track of the directory index offset of the child last checked in the
last call to can_rmdir(), and then use it as the starting point for
future calls to can_rmdir().

Signed-off-by: default avatarRobbie Ko <robbieko@synology.com>
Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
[ update changelog ]
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 35c8eda1

fs/btrfs/send.c

+22 −9
Original line number Diff line number Diff line
@@ -235,6 +235,7 @@ struct orphan_dir_info { 
	struct rb_node node;

	u64 ino;

	u64 gen;

	u64 last_dir_index_offset;

};



struct name_cache_entry {
@@ -2861,6 +2862,7 @@ add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino) 
		return ERR_PTR(-ENOMEM);

	odi->ino = dir_ino;

	odi->gen = 0;

	odi->last_dir_index_offset = 0;



	rb_link_node(&odi->node, parent, p);

	rb_insert_color(&odi->node, &sctx->orphan_dirs);
@@ -2916,6 +2918,7 @@ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen, 
	struct btrfs_key found_key;

	struct btrfs_key loc;

	struct btrfs_dir_item *di;

	struct orphan_dir_info *odi = NULL;



	/*

	 * Don't try to rmdir the top/root subvolume dir.
@@ -2930,6 +2933,11 @@ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen, 
	key.objectid = dir;

	key.type = BTRFS_DIR_INDEX_KEY;

	key.offset = 0;



	odi = get_orphan_dir_info(sctx, dir);

	if (odi)

		key.offset = odi->last_dir_index_offset;



	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);

	if (ret < 0)

		goto out;
@@ -2957,30 +2965,33 @@ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen, 


		dm = get_waiting_dir_move(sctx, loc.objectid);

		if (dm) {

			struct orphan_dir_info *odi;



			odi = add_orphan_dir_info(sctx, dir);

			if (IS_ERR(odi)) {

				ret = PTR_ERR(odi);

				goto out;

			}

			odi->gen = dir_gen;

			odi->last_dir_index_offset = found_key.offset;

			dm->rmdir_ino = dir;

			ret = 0;

			goto out;

		}



		if (loc.objectid > send_progress) {

			struct orphan_dir_info *odi;



			odi = get_orphan_dir_info(sctx, dir);

			free_orphan_dir_info(sctx, odi);

			odi = add_orphan_dir_info(sctx, dir);

			if (IS_ERR(odi)) {

				ret = PTR_ERR(odi);

				goto out;

			}

			odi->gen = dir_gen;

			odi->last_dir_index_offset = found_key.offset;

			ret = 0;

			goto out;

		}



		path->slots[0]++;

	}

	free_orphan_dir_info(sctx, odi);



	ret = 1;
@@ -3258,13 +3269,16 @@ static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm) 


	if (rmdir_ino) {

		struct orphan_dir_info *odi;

		u64 gen;



		odi = get_orphan_dir_info(sctx, rmdir_ino);

		if (!odi) {

			/* already deleted */

			goto finish;

		}

		ret = can_rmdir(sctx, rmdir_ino, odi->gen, sctx->cur_ino);

		gen = odi->gen;



		ret = can_rmdir(sctx, rmdir_ino, gen, sctx->cur_ino);

		if (ret < 0)

			goto out;

		if (!ret)
@@ -3275,13 +3289,12 @@ static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm) 
			ret = -ENOMEM;

			goto out;

		}

		ret = get_cur_path(sctx, rmdir_ino, odi->gen, name);

		ret = get_cur_path(sctx, rmdir_ino, gen, name);

		if (ret < 0)

			goto out;

		ret = send_rmdir(sctx, name);

		if (ret < 0)

			goto out;

		free_orphan_dir_info(sctx, odi);

	}



finish:

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