Commit 30e3c897 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: raid56: extract the pq generation code into a helper 



Currently finish_rmw() will update the P/Q stripes before submitting
the writes.

It's done behind a for(;;) loop, it's a little congested indent-wise, so
extract the code into a helper called generate_pq_vertical().

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 9c5ff9b4

fs/btrfs/raid56.c

+44 −46
Original line number Diff line number Diff line
@@ -1193,6 +1193,48 @@ static void bio_get_trace_info(struct btrfs_raid_bio *rbio, struct bio *bio, 
	trace_info->stripe_nr = -1;

}



/* Generate PQ for one veritical stripe. */

static void generate_pq_vertical(struct btrfs_raid_bio *rbio, int sectornr)

{

	void **pointers = rbio->finish_pointers;

	const u32 sectorsize = rbio->bioc->fs_info->sectorsize;

	struct sector_ptr *sector;

	int stripe;

	const bool has_qstripe = rbio->bioc->map_type & BTRFS_BLOCK_GROUP_RAID6;



	/* First collect one sector from each data stripe */

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

		sector = sector_in_rbio(rbio, stripe, sectornr, 0);

		pointers[stripe] = kmap_local_page(sector->page) +

				   sector->pgoff;

	}



	/* Then add the parity stripe */

	sector = rbio_pstripe_sector(rbio, sectornr);

	sector->uptodate = 1;

	pointers[stripe++] = kmap_local_page(sector->page) + sector->pgoff;



	if (has_qstripe) {

		/*

		 * RAID6, add the qstripe and call the library function

		 * to fill in our p/q

		 */

		sector = rbio_qstripe_sector(rbio, sectornr);

		sector->uptodate = 1;

		pointers[stripe++] = kmap_local_page(sector->page) +

				     sector->pgoff;



		raid6_call.gen_syndrome(rbio->real_stripes, sectorsize,

					pointers);

	} else {

		/* raid5 */

		memcpy(pointers[rbio->nr_data], pointers[0], sectorsize);

		run_xor(pointers + 1, rbio->nr_data - 1, sectorsize);

	}

	for (stripe = stripe - 1; stripe >= 0; stripe--)

		kunmap_local(pointers[stripe]);

}



/*

 * this is called from one of two situations.  We either

 * have a full stripe from the higher layers, or we've read all
@@ -1204,28 +1246,17 @@ static void bio_get_trace_info(struct btrfs_raid_bio *rbio, struct bio *bio, 
static noinline void finish_rmw(struct btrfs_raid_bio *rbio)

{

	struct btrfs_io_context *bioc = rbio->bioc;

	const u32 sectorsize = bioc->fs_info->sectorsize;

	void **pointers = rbio->finish_pointers;

	int nr_data = rbio->nr_data;

	/* The total sector number inside the full stripe. */

	int total_sector_nr;

	int stripe;

	/* Sector number inside a stripe. */

	int sectornr;

	bool has_qstripe;

	struct bio_list bio_list;

	struct bio *bio;

	int ret;



	bio_list_init(&bio_list);



	if (rbio->real_stripes - rbio->nr_data == 1)

		has_qstripe = false;

	else if (rbio->real_stripes - rbio->nr_data == 2)

		has_qstripe = true;

	else

		BUG();



	/* We should have at least one data sector. */

	ASSERT(bitmap_weight(&rbio->dbitmap, rbio->stripe_nsectors));
@@ -1258,41 +1289,8 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio) 
	else

		clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);



	for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) {

		struct sector_ptr *sector;



		/* First collect one sector from each data stripe */

		for (stripe = 0; stripe < nr_data; stripe++) {

			sector = sector_in_rbio(rbio, stripe, sectornr, 0);

			pointers[stripe] = kmap_local_page(sector->page) +

					   sector->pgoff;

		}



		/* Then add the parity stripe */

		sector = rbio_pstripe_sector(rbio, sectornr);

		sector->uptodate = 1;

		pointers[stripe++] = kmap_local_page(sector->page) + sector->pgoff;



		if (has_qstripe) {

			/*

			 * RAID6, add the qstripe and call the library function

			 * to fill in our p/q

			 */

			sector = rbio_qstripe_sector(rbio, sectornr);

			sector->uptodate = 1;

			pointers[stripe++] = kmap_local_page(sector->page) +

					     sector->pgoff;



			raid6_call.gen_syndrome(rbio->real_stripes, sectorsize,

						pointers);

		} else {

			/* raid5 */

			memcpy(pointers[nr_data], pointers[0], sectorsize);

			run_xor(pointers + 1, nr_data - 1, sectorsize);

		}

		for (stripe = stripe - 1; stripe >= 0; stripe--)

			kunmap_local(pointers[stripe]);

	}

	for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++)

		generate_pq_vertical(rbio, sectornr);



	/*

	 * Start writing.  Make bios for everything from the higher layers (the