Commit 78a213a0 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by David Sterba
Browse files

btrfs: optimize simple reads in btrfsic_map_block 



Pass a smap into __btrfs_map_block so that the usual case of a read that
doesn't require parity raid recovery doesn't need an extra memory
allocation for the btrfs_io_context.

Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 3965a4c7

fs/btrfs/check-integrity.c

+12 −7
Original line number Diff line number Diff line
@@ -1459,13 +1459,13 @@ static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len, 
	struct btrfs_fs_info *fs_info = state->fs_info;

	int ret;

	u64 length;

	struct btrfs_io_context *multi = NULL;

	struct btrfs_io_context *bioc = NULL;

	struct btrfs_io_stripe smap, *map;

	struct btrfs_device *device;



	length = len;

	ret = btrfs_map_block(fs_info, BTRFS_MAP_READ,

			      bytenr, &length, &multi, mirror_num);



	ret = __btrfs_map_block(fs_info, BTRFS_MAP_READ, bytenr, &length, &bioc,

				NULL, &mirror_num, 0);

	if (ret) {

		block_ctx_out->start = 0;

		block_ctx_out->dev_bytenr = 0;
@@ -1478,21 +1478,26 @@ static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len, 
		return ret;

	}



	device = multi->stripes[0].dev;

	if (bioc)

		map = &bioc->stripes[0];

	else

		map = &smap;



	device = map->dev;

	if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state) ||

	    !device->bdev || !device->name)

		block_ctx_out->dev = NULL;

	else

		block_ctx_out->dev = btrfsic_dev_state_lookup(

							device->bdev->bd_dev);

	block_ctx_out->dev_bytenr = multi->stripes[0].physical;

	block_ctx_out->dev_bytenr = map->physical;

	block_ctx_out->start = bytenr;

	block_ctx_out->len = len;

	block_ctx_out->datav = NULL;

	block_ctx_out->pagev = NULL;

	block_ctx_out->mem_to_free = NULL;



	kfree(multi);

	kfree(bioc);

	if (NULL == block_ctx_out->dev) {

		ret = -ENXIO;

		pr_info("btrfsic: error, cannot lookup dev (#1)!\n");