Commit 381b9b4c authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: use integrated bitmaps for scrub_parity::dbitmap and ebitmap 



Previously 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 scrub_parity.

To be extra safe, add an ASSERT() making sure calclulated @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 c67c68eb

fs/btrfs/scrub.c

+13 −24
Original line number Diff line number Diff line
@@ -135,15 +135,13 @@ struct scrub_parity { 
	struct work_struct	work;



	/* Mark the parity blocks which have data */

	unsigned long		*dbitmap;

	unsigned long		dbitmap;



	/*

	 * Mark the parity blocks which have data, but errors happen when

	 * read data or check data

	 */

	unsigned long		*ebitmap;



	unsigned long		bitmap[];

	unsigned long		ebitmap;

};



struct scrub_ctx {
@@ -2406,13 +2404,13 @@ static inline void __scrub_mark_bitmap(struct scrub_parity *sparity, 
static inline void scrub_parity_mark_sectors_error(struct scrub_parity *sparity,

						   u64 start, u32 len)

{

	__scrub_mark_bitmap(sparity, sparity->ebitmap, start, len);

	__scrub_mark_bitmap(sparity, &sparity->ebitmap, start, len);

}



static inline void scrub_parity_mark_sectors_data(struct scrub_parity *sparity,

						  u64 start, u32 len)

{

	__scrub_mark_bitmap(sparity, sparity->dbitmap, start, len);

	__scrub_mark_bitmap(sparity, &sparity->dbitmap, start, len);

}



static void scrub_block_complete(struct scrub_block *sblock)
@@ -2763,7 +2761,7 @@ static void scrub_free_parity(struct scrub_parity *sparity) 
	struct scrub_sector *curr, *next;

	int nbits;



	nbits = bitmap_weight(sparity->ebitmap, sparity->nsectors);

	nbits = bitmap_weight(&sparity->ebitmap, sparity->nsectors);

	if (nbits) {

		spin_lock(&sctx->stat_lock);

		sctx->stat.read_errors += nbits;
@@ -2795,8 +2793,8 @@ static void scrub_parity_bio_endio(struct bio *bio) 
	struct btrfs_fs_info *fs_info = sparity->sctx->fs_info;



	if (bio->bi_status)

		bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,

			  sparity->nsectors);

		bitmap_or(&sparity->ebitmap, &sparity->ebitmap,

			  &sparity->dbitmap, sparity->nsectors);



	bio_put(bio);
@@ -2814,8 +2812,8 @@ static void scrub_parity_check_and_repair(struct scrub_parity *sparity) 
	u64 length;

	int ret;



	if (!bitmap_andnot(sparity->dbitmap, sparity->dbitmap, sparity->ebitmap,

			   sparity->nsectors))

	if (!bitmap_andnot(&sparity->dbitmap, &sparity->dbitmap,

			   &sparity->ebitmap, sparity->nsectors))

		goto out;



	length = sparity->logic_end - sparity->logic_start;
@@ -2833,7 +2831,7 @@ static void scrub_parity_check_and_repair(struct scrub_parity *sparity) 


	rbio = raid56_parity_alloc_scrub_rbio(bio, bioc, length,

					      sparity->scrub_dev,

					      sparity->dbitmap,

					      &sparity->dbitmap,

					      sparity->nsectors);

	if (!rbio)

		goto rbio_out;
@@ -2847,7 +2845,7 @@ static void scrub_parity_check_and_repair(struct scrub_parity *sparity) 
bioc_out:

	btrfs_bio_counter_dec(fs_info);

	btrfs_put_bioc(bioc);

	bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,

	bitmap_or(&sparity->ebitmap, &sparity->ebitmap, &sparity->dbitmap,

		  sparity->nsectors);

	spin_lock(&sctx->stat_lock);

	sctx->stat.malloc_errors++;
@@ -2856,11 +2854,6 @@ static void scrub_parity_check_and_repair(struct scrub_parity *sparity) 
	scrub_free_parity(sparity);

}



static inline int scrub_calc_parity_bitmap_len(int nsectors)

{

	return DIV_ROUND_UP(nsectors, BITS_PER_LONG) * sizeof(long);

}



static void scrub_parity_get(struct scrub_parity *sparity)

{

	refcount_inc(&sparity->refs);
@@ -3131,7 +3124,6 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx, 
	int ret;

	struct scrub_parity *sparity;

	int nsectors;

	int bitmap_len;



	path = btrfs_alloc_path();

	if (!path) {
@@ -3145,9 +3137,8 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx, 


	ASSERT(map->stripe_len <= U32_MAX);

	nsectors = map->stripe_len >> fs_info->sectorsize_bits;

	bitmap_len = scrub_calc_parity_bitmap_len(nsectors);

	sparity = kzalloc(sizeof(struct scrub_parity) + 2 * bitmap_len,

			  GFP_NOFS);

	ASSERT(nsectors <= BITS_PER_LONG);

	sparity = kzalloc(sizeof(struct scrub_parity), GFP_NOFS);

	if (!sparity) {

		spin_lock(&sctx->stat_lock);

		sctx->stat.malloc_errors++;
@@ -3165,8 +3156,6 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx, 
	sparity->logic_end = logic_end;

	refcount_set(&sparity->refs, 1);

	INIT_LIST_HEAD(&sparity->sectors_list);

	sparity->dbitmap = sparity->bitmap;

	sparity->ebitmap = (void *)sparity->bitmap + bitmap_len;



	ret = 0;

	for (cur_logical = logic_start; cur_logical < logic_end;