Commit b3047a42 authored Jan 11, 2023 by Filipe Manana Committed by David Sterba Feb 13, 2023

btrfs: send: directly return from will_overwrite_ref() and simplify it

There are no resources to release before will_overwrite_ref() returns, so
we don't really need the 'out' label and jumping to it when conditions are
met - we can directly return and get rid of the label and jumps. Also we
can deal with -ENOENT and other errors in a single if-else logic, as it's
more straightforward.

This helps the next patch in the series to be more simple as well.

This patch is part of a larger patchset and the changelog of the last
patch in the series contains a sample performance test and results.
The patches that comprise the patchset are the following:

btrfs: send: directly return from did_overwrite_ref() and simplify it
btrfs: send: avoid unnecessary generation search at did_overwrite_ref()
btrfs: send: directly return from will_overwrite_ref() and simplify it
btrfs: send: avoid extra b+tree searches when checking reference overrides
btrfs: send: remove send_progress argument from can_rmdir()
btrfs: send: avoid duplicated orphan dir allocation and initialization
btrfs: send: avoid unnecessary orphan dir rbtree search at can_rmdir()
btrfs: send: reduce searches on parent root when checking if dir can be removed
btrfs: send: iterate waiting dir move rbtree only once when processing refs
btrfs: send: initialize all the red black trees earlier
btrfs: send: genericize the backref cache to allow it to be reused
btrfs: adapt lru cache to allow for 64 bits keys on 32 bits systems
btrfs: send: cache information about created directories
btrfs: allow a generation number to be associated with lru cache entries
btrfs: add an api to delete a specific entry from the lru cache
btrfs: send: use the lru cache to implement the name cache
btrfs: send: update size of roots array for backref cache entries
btrfs: send: cache utimes operations for directories if possible

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

parent cb689481

fs/btrfs/send.c

+16 −22

Original line number	Diff line number	Diff line
		@@ -2119,17 +2119,17 @@ static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen,
		const char *name, int name_len,
		u64 who_ino, u64 who_gen, u64 *who_mode)
		{
		int ret = 0;
		int ret;
		u64 gen;
		u64 other_inode = 0;
		struct btrfs_inode_info info;

		if (!sctx->parent_root)
		goto out;
		return 0;

		ret = is_inode_existent(sctx, dir, dir_gen);
		if (ret <= 0)
		goto out;
		return 0;

		/*
		* If we have a parent root we need to verify that the parent dir was
		@@ -2138,24 +2138,21 @@ static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen,
		*/
		if (sctx->parent_root && dir != BTRFS_FIRST_FREE_OBJECTID) {
		ret = get_inode_gen(sctx->parent_root, dir, &gen);
		if (ret < 0 && ret != -ENOENT)
		goto out;
		if (ret) {
		ret = 0;
		goto out;
		}
		if (ret == -ENOENT)
		return 0;
		else if (ret < 0)
		return ret;

		if (gen != dir_gen)
		goto out;
		return 0;
		}

		ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len,
		&other_inode);
		if (ret < 0 && ret != -ENOENT)
		goto out;
		if (ret) {
		ret = 0;
		goto out;
		}
		if (ret == -ENOENT)
		return 0;
		else if (ret < 0)
		return ret;

		/*
		* Check if the overwritten ref was already processed. If yes, the ref
		@@ -2166,18 +2163,15 @@ static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen,
		is_waiting_for_move(sctx, other_inode)) {
		ret = get_inode_info(sctx->parent_root, other_inode, &info);
		if (ret < 0)
		goto out;
		return ret;

		ret = 1;
		*who_ino = other_inode;
		*who_gen = info.gen;
		*who_mode = info.mode;
		} else {
		ret = 0;
		return 1;
		}

		out:
		return ret;
		return 0;
		}

		/*