Commit e739ba30 authored Jan 11, 2023 by Filipe Manana Committed by David Sterba Feb 13, 2023

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

There are no resources to release before did_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 b7625f46

fs/btrfs/send.c

+18 −25

Original line number	Diff line number	Diff line
		@@ -2192,48 +2192,44 @@ static int did_overwrite_ref(struct send_ctx *sctx,
		u64 ino, u64 ino_gen,
		const char *name, int name_len)
		{
		int ret = 0;
		int ret;
		u64 gen;
		u64 ow_inode;

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

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

		if (dir != BTRFS_FIRST_FREE_OBJECTID) {
		ret = get_inode_gen(sctx->send_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;
		}

		/* check if the ref was overwritten by another ref */
		ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len,
		&ow_inode);
		if (ret < 0 && ret != -ENOENT)
		goto out;
		if (ret) {
		if (ret == -ENOENT) {
		/* was never and will never be overwritten */
		ret = 0;
		goto out;
		return 0;
		} else if (ret < 0) {
		return ret;
		}

		ret = get_inode_gen(sctx->send_root, ow_inode, &gen);
		if (ret < 0)
		goto out;
		return ret;

		if (ow_inode == ino && gen == ino_gen) {
		ret = 0;
		goto out;
		}
		if (ow_inode == ino && gen == ino_gen)
		return 0;

		/*
		* We know that it is or will be overwritten. Check this now.
		@@ -2244,12 +2240,9 @@ static int did_overwrite_ref(struct send_ctx *sctx,
		if ((ow_inode < sctx->send_progress) \|\|
		(ino != sctx->cur_ino && ow_inode == sctx->cur_ino &&
		gen == sctx->cur_inode_gen))
		ret = 1;
		else
		ret = 0;
		return 1;

		out:
		return ret;
		return 0;
		}

		/*