Commit c67c68eb authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: use integrated bitmaps for btrfs_raid_bio::dbitmap and finish_pbitmap 



Previsouly we use "unsigned long *" for those two bitmaps.

But since we only support fixed stripe length (64KiB, already checked in
tree-checker), "unsigned long *" is really a waste of memory, while we
can just use "unsigned long".

This saves us 8 bytes in total for btrfs_raid_bio.

To be extra safe, add an ASSERT() making sure calculated
@stripe_nsectors is always smaller than BITS_PER_LONG.

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 099aa972

fs/btrfs/raid56.c

+22 −20
Original line number Diff line number Diff line
@@ -164,6 +164,13 @@ struct btrfs_raid_bio { 
	atomic_t stripes_pending;



	atomic_t error;



	/* Bitmap to record which horizontal stripe has data */

	unsigned long dbitmap;



	/* Allocated with stripe_nsectors-many bits for finish_*() calls */

	unsigned long finish_pbitmap;



	/*

	 * these are two arrays of pointers.  We allocate the

	 * rbio big enough to hold them both and setup their
@@ -184,14 +191,8 @@ struct btrfs_raid_bio { 
	 */

	struct sector_ptr *stripe_sectors;



	/* Bitmap to record which horizontal stripe has data */

	unsigned long *dbitmap;



	/* allocated with real_stripes-many pointers for finish_*() calls */

	void **finish_pointers;



	/* Allocated with stripe_nsectors-many bits for finish_*() calls */

	unsigned long *finish_pbitmap;

};



static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
@@ -1038,14 +1039,17 @@ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info, 
	ASSERT(IS_ALIGNED(stripe_len, PAGE_SIZE));

	/* PAGE_SIZE must also be aligned to sectorsize for subpage support */

	ASSERT(IS_ALIGNED(PAGE_SIZE, fs_info->sectorsize));

	/*

	 * Our current stripe len should be fixed to 64k thus stripe_nsectors

	 * (at most 16) should be no larger than BITS_PER_LONG.

	 */

	ASSERT(stripe_nsectors <= BITS_PER_LONG);



	rbio = kzalloc(sizeof(*rbio) +

		       sizeof(*rbio->stripe_pages) * num_pages +

		       sizeof(*rbio->bio_sectors) * num_sectors +

		       sizeof(*rbio->stripe_sectors) * num_sectors +

		       sizeof(*rbio->finish_pointers) * real_stripes +

		       sizeof(*rbio->dbitmap) * BITS_TO_LONGS(stripe_nsectors) +

		       sizeof(*rbio->finish_pbitmap) * BITS_TO_LONGS(stripe_nsectors),

		       sizeof(*rbio->finish_pointers) * real_stripes,

		       GFP_NOFS);

	if (!rbio)

		return ERR_PTR(-ENOMEM);
@@ -1081,8 +1085,6 @@ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info, 
	CONSUME_ALLOC(rbio->bio_sectors, num_sectors);

	CONSUME_ALLOC(rbio->stripe_sectors, num_sectors);

	CONSUME_ALLOC(rbio->finish_pointers, real_stripes);

	CONSUME_ALLOC(rbio->dbitmap, BITS_TO_LONGS(stripe_nsectors));

	CONSUME_ALLOC(rbio->finish_pbitmap, BITS_TO_LONGS(stripe_nsectors));

#undef  CONSUME_ALLOC



	if (bioc->map_type & BTRFS_BLOCK_GROUP_RAID5)
@@ -1939,7 +1941,7 @@ static void __raid_recover_end_io(struct btrfs_raid_bio *rbio) 
		 * which we have data when doing parity scrub.

		 */

		if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB &&

		    !test_bit(sectornr, rbio->dbitmap))

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

			continue;



		/*
@@ -2374,7 +2376,7 @@ struct btrfs_raid_bio *raid56_parity_alloc_scrub_rbio(struct bio *bio, 
	}

	ASSERT(i < rbio->real_stripes);



	bitmap_copy(rbio->dbitmap, dbitmap, stripe_nsectors);

	bitmap_copy(&rbio->dbitmap, dbitmap, stripe_nsectors);



	/*

	 * We have already increased bio_counter when getting bioc, record it
@@ -2412,7 +2414,7 @@ static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio) 
	int stripe;

	int sectornr;



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

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

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

			struct page *page;

			int index = (stripe * rbio->stripe_nsectors + sectornr) *
@@ -2437,7 +2439,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, 
	struct btrfs_io_context *bioc = rbio->bioc;

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

	void **pointers = rbio->finish_pointers;

	unsigned long *pbitmap = rbio->finish_pbitmap;

	unsigned long *pbitmap = &rbio->finish_pbitmap;

	int nr_data = rbio->nr_data;

	int stripe;

	int sectornr;
@@ -2460,7 +2462,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, 


	if (bioc->num_tgtdevs && bioc->tgtdev_map[rbio->scrubp]) {

		is_replace = 1;

		bitmap_copy(pbitmap, rbio->dbitmap, rbio->stripe_nsectors);

		bitmap_copy(pbitmap, &rbio->dbitmap, rbio->stripe_nsectors);

	}



	/*
@@ -2497,7 +2499,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, 
	/* Map the parity stripe just once */

	pointers[nr_data] = kmap_local_page(p_sector.page);



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

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

		struct sector_ptr *sector;

		void *parity;
@@ -2525,7 +2527,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, 
			memcpy(parity, pointers[rbio->scrubp], sectorsize);

		else

			/* Parity is right, needn't writeback */

			bitmap_clear(rbio->dbitmap, sectornr, 1);

			bitmap_clear(&rbio->dbitmap, sectornr, 1);

		kunmap_local(parity);



		for (stripe = nr_data - 1; stripe >= 0; stripe--)
@@ -2547,7 +2549,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, 
	 * higher layers (the bio_list in our rbio) and our p/q.  Ignore

	 * everything else.

	 */

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

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

		struct sector_ptr *sector;



		sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
@@ -2714,7 +2716,7 @@ static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio) 
	 * stripe

	 */

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

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

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

			struct sector_ptr *sector;

			/*

			 * We want to find all the sectors missing from the