Commit 1c10702e authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: raid56: avoid double for loop inside raid56_parity_scrub_stripe() 



Originally it's iterating all the sectors which has dbitmap sector for
the vertical stripe.

It can be easily converted to sector bytenr iteration with an test_bit()
call.

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 550cdeb3

fs/btrfs/raid56.c

+31 −31
Original line number Diff line number Diff line
@@ -2661,8 +2661,7 @@ static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio) 
	int bios_to_read = 0;

	struct bio_list bio_list;

	int ret;

	int sectornr;

	int stripe;

	int total_sector_nr;

	struct bio *bio;



	bio_list_init(&bio_list);
@@ -2672,18 +2671,21 @@ static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio) 
		goto cleanup;



	atomic_set(&rbio->error, 0);

	/*

	 * build a list of bios to read all the missing parts of this

	 * stripe

	 */

	for (stripe = 0; stripe < rbio->real_stripes; stripe++) {

		for_each_set_bit(sectornr, &rbio->dbitmap, rbio->stripe_nsectors) {

	/* Build a list of bios to read all the missing parts. */

	for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;

	     total_sector_nr++) {

		int sectornr = total_sector_nr % rbio->stripe_nsectors;

		int stripe = total_sector_nr / rbio->stripe_nsectors;

		struct sector_ptr *sector;



		/* No data in the vertical stripe, no need to read. */

		if (!test_bit(sectornr, &rbio->dbitmap))

			continue;



		/*

			 * We want to find all the sectors missing from the

			 * rbio and read them from the disk.  If * sector_in_rbio()

			 * finds a sector in the bio list we don't need to read

			 * it off the stripe.

		 * We want to find all the sectors missing from the rbio and

		 * read them from the disk. If sector_in_rbio() finds a sector

		 * in the bio list we don't need to read it off the stripe.

		 */

		sector = sector_in_rbio(rbio, stripe, sectornr, 1);

		if (sector)
@@ -2691,19 +2693,17 @@ static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio) 


		sector = rbio_stripe_sector(rbio, stripe, sectornr);

		/*

			 * The bio cache may have handed us an uptodate sector.

			 * If so, be happy and use it.

		 * The bio cache may have handed us an uptodate sector.  If so,

		 * use it.

		 */

		if (sector->uptodate)

			continue;



			ret = rbio_add_io_sector(rbio, &bio_list, sector,

						 stripe, sectornr, rbio->stripe_len,

						 REQ_OP_READ);

		ret = rbio_add_io_sector(rbio, &bio_list, sector, stripe,

					 sectornr, rbio->stripe_len, REQ_OP_READ);

		if (ret)

			goto cleanup;

	}

	}



	bios_to_read = bio_list_size(&bio_list);

	if (!bios_to_read) {