Commit b6296858 authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
Browse files

btrfs: remove roots ulist when checking data extent sharedness 



Currently btrfs_is_data_extent_shared() is passing a ulist for the roots
argument of find_parent_nodes(), however it does not use that ulist for
anything and for this context that list always ends up with at most one
element.

Since find_parent_nodes() is able to deal with a NULL ulist for its roots
argument, make btrfs_is_data_extent_shared() pass it NULL and avoid the
burden of allocating memory for the unnused roots ulist, initializing it,
releasing it and allocating one struct ulist_node for it during the call
to find_parent_nodes().

Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 84a7949d

fs/btrfs/backref.c

+1 −5
Original line number Diff line number Diff line
@@ -1664,7 +1664,6 @@ struct btrfs_backref_share_check_ctx *btrfs_alloc_backref_share_check_ctx(void) 
		return NULL;



	ulist_init(&ctx->refs);

	ulist_init(&ctx->roots);



	return ctx;

}
@@ -1675,7 +1674,6 @@ void btrfs_free_backref_share_ctx(struct btrfs_backref_share_check_ctx *ctx) 
		return;



	ulist_release(&ctx->refs);

	ulist_release(&ctx->roots);

	kfree(ctx);

}
@@ -1718,7 +1716,6 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr, 
	};

	int level;



	ulist_init(&ctx->roots);

	ulist_init(&ctx->refs);



	trans = btrfs_join_transaction_nostart(root);
@@ -1742,7 +1739,7 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr, 
		bool cached;



		ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, &ctx->refs,

					&ctx->roots, NULL, &shared, false);

					NULL, NULL, &shared, false);

		if (ret == BACKREF_FOUND_SHARED) {

			/* this is the only condition under which we return 1 */

			ret = 1;
@@ -1810,7 +1807,6 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr, 
		up_read(&fs_info->commit_root_sem);

	}

out:

	ulist_release(&ctx->roots);

	ulist_release(&ctx->refs);

	return ret;

}

fs/btrfs/backref.h

+0 −1
Original line number Diff line number Diff line
@@ -26,7 +26,6 @@ struct btrfs_backref_shared_cache_entry { 
struct btrfs_backref_share_check_ctx {

	/* Ulists used during backref walking. */

	struct ulist refs;

	struct ulist roots;

	/*

	 * A path from a root to a leaf that has a file extent item pointing to

	 * a given data extent should never exceed the maximum b+tree height.