Commit 928ff3be authored by Christoph Hellwig's avatar Christoph Hellwig Committed by David Sterba
Browse files

btrfs: stop allocation a btrfs_io_context for simple I/O 



The I/O context structure is only used to pass the btrfs_device to
the end I/O handler for I/Os that go to a single device.

Stop allocating the I/O context for these cases by passing the optional
btrfs_io_stripe argument to __btrfs_map_block to query the mapping
information and then using a fast path submission and I/O completion
handler.  As the old btrfs_io_context based I/O submission path is
only used for mirrored writes, rename the functions to make that
clear and stop setting the btrfs_bio device and mirror_num field
that is only used for reads.

Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: default avatarAnand Jain <anand.jain@oracle.com>
Tested-by: default avatarNikolay Borisov <nborisov@suse.com>
Tested-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 03793cbb

fs/btrfs/volumes.c

+57 −37
Original line number Diff line number Diff line
@@ -6706,11 +6706,12 @@ static void btrfs_log_dev_io_error(struct bio *bio, struct btrfs_device *dev) 
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_FLUSH_ERRS);

}



static struct workqueue_struct *btrfs_end_io_wq(struct btrfs_io_context *bioc)

static struct workqueue_struct *btrfs_end_io_wq(struct btrfs_fs_info *fs_info,

						struct bio *bio)

{

	if (bioc->orig_bio->bi_opf & REQ_META)

		return bioc->fs_info->endio_meta_workers;

	return bioc->fs_info->endio_workers;

	if (bio->bi_opf & REQ_META)

		return fs_info->endio_meta_workers;

	return fs_info->endio_workers;

}



static void btrfs_end_bio_work(struct work_struct *work)
@@ -6721,6 +6722,24 @@ static void btrfs_end_bio_work(struct work_struct *work) 
	bbio->end_io(bbio);

}



static void btrfs_simple_end_io(struct bio *bio)

{

	struct btrfs_fs_info *fs_info = bio->bi_private;

	struct btrfs_bio *bbio = btrfs_bio(bio);



	btrfs_bio_counter_dec(fs_info);



	if (bio->bi_status)

		btrfs_log_dev_io_error(bio, bbio->device);



	if (bio_op(bio) == REQ_OP_READ) {

		INIT_WORK(&bbio->end_io_work, btrfs_end_bio_work);

		queue_work(btrfs_end_io_wq(fs_info, bio), &bbio->end_io_work);

	} else {

		bbio->end_io(bbio);

	}

}



static void btrfs_raid56_end_io(struct bio *bio)

{

	struct btrfs_io_context *bioc = bio->bi_private;
@@ -6733,7 +6752,7 @@ static void btrfs_raid56_end_io(struct bio *bio) 
	btrfs_put_bioc(bioc);

}



static void btrfs_end_bio(struct bio *bio)

static void btrfs_orig_write_end_io(struct bio *bio)

{

	struct btrfs_io_stripe *stripe = bio->bi_private;

	struct btrfs_io_context *bioc = stripe->bioc;
@@ -6746,8 +6765,6 @@ static void btrfs_end_bio(struct bio *bio) 
		btrfs_log_dev_io_error(bio, stripe->dev);

	}



	bbio->mirror_num = bioc->mirror_num;



	/*

	 * Only send an error to the higher layers if it is beyond the tolerance

	 * threshold.
@@ -6757,13 +6774,7 @@ static void btrfs_end_bio(struct bio *bio) 
	else

		bio->bi_status = BLK_STS_OK;



	if (btrfs_op(bio) == BTRFS_MAP_READ) {

		INIT_WORK(&bbio->end_io_work, btrfs_end_bio_work);

		queue_work(btrfs_end_io_wq(bioc), &bbio->end_io_work);

	} else {

	bbio->end_io(bbio);

	}



	btrfs_put_bioc(bioc);

}
@@ -6820,15 +6831,16 @@ static void btrfs_submit_dev_bio(struct btrfs_device *dev, struct bio *bio) 
	submit_bio(bio);

}



static void submit_stripe_bio(struct btrfs_io_context *bioc, int dev_nr)

static void btrfs_submit_mirrored_bio(struct btrfs_io_context *bioc, int dev_nr)

{

	struct bio *orig_bio = bioc->orig_bio, *bio;



	ASSERT(bio_op(orig_bio) != REQ_OP_READ);



	/* Reuse the bio embedded into the btrfs_bio for the last mirror */

	if (dev_nr == bioc->num_stripes - 1) {

		bio = orig_bio;

		btrfs_bio(bio)->device = bioc->stripes[dev_nr].dev;

		bio->bi_end_io = btrfs_end_bio;

		bio->bi_end_io = btrfs_orig_write_end_io;

	} else {

		bio = bio_alloc_clone(NULL, orig_bio, GFP_NOFS, &fs_bio_set);

		bio_inc_remaining(orig_bio);
@@ -6846,34 +6858,19 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror 
	u64 logical = bio->bi_iter.bi_sector << 9;

	u64 length = bio->bi_iter.bi_size;

	u64 map_length = length;

	int ret;

	int dev_nr;

	int total_devs;

	struct btrfs_io_context *bioc = NULL;

	struct btrfs_io_stripe smap;

	int ret;



	btrfs_bio_counter_inc_blocked(fs_info);

	ret = __btrfs_map_block(fs_info, btrfs_op(bio), logical, &map_length,

				&bioc, NULL, &mirror_num, 1);

				&bioc, &smap, &mirror_num, 1);

	if (ret) {

		btrfs_bio_counter_dec(fs_info);

		btrfs_bio_end_io(btrfs_bio(bio), errno_to_blk_status(ret));

		return;

	}



	total_devs = bioc->num_stripes;

	bioc->orig_bio = bio;



	if ((bioc->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&

	    ((btrfs_op(bio) == BTRFS_MAP_WRITE) || (mirror_num > 1))) {

		bio->bi_private = bioc;

		bio->bi_end_io = btrfs_raid56_end_io;

		if (btrfs_op(bio) == BTRFS_MAP_WRITE)

			raid56_parity_write(bio, bioc);

		else

			raid56_parity_recover(bio, bioc, mirror_num);

		return;

	}



	if (map_length < length) {

		btrfs_crit(fs_info,

			   "mapping failed logical %llu bio len %llu len %llu",
@@ -6881,8 +6878,31 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror 
		BUG();

	}



	if (!bioc) {

		/* Single mirror read/write fast path */

		btrfs_bio(bio)->mirror_num = mirror_num;

		btrfs_bio(bio)->device = smap.dev;

		bio->bi_iter.bi_sector = smap.physical >> SECTOR_SHIFT;

		bio->bi_private = fs_info;

		bio->bi_end_io = btrfs_simple_end_io;

		btrfs_submit_dev_bio(smap.dev, bio);

	} else if (bioc->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) {

		/* Parity RAID write or read recovery */

		bio->bi_private = bioc;

		bio->bi_end_io = btrfs_raid56_end_io;

		if (bio_op(bio) == REQ_OP_READ)

			raid56_parity_recover(bio, bioc, mirror_num);

		else

			raid56_parity_write(bio, bioc);

	} else {

		/* Write to multiple mirrors */

		int total_devs = bioc->num_stripes;

		int dev_nr;



		bioc->orig_bio = bio;

		for (dev_nr = 0; dev_nr < total_devs; dev_nr++)

		submit_stripe_bio(bioc, dev_nr);

			btrfs_submit_mirrored_bio(bioc, dev_nr);

	}

}



static bool dev_args_match_fs_devices(const struct btrfs_dev_lookup_args *args,