btrfs: raid56: move sector_ptr::uptodate into a dedicated bitmap

The uptodate boolean member can be extracted into a bitmap, which will
save us some space (1 bit in a byte vs 8 bits in a byte).

Furthermore we do not need to record the uptodate bitmap for bio
sectors, as if bio_sectors[].paddr is valid it means there is a bio and
will be uptodate.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: adam900710

fs/btrfs/raid56.c

@@ -151,7 +151,6 @@ struct sector_ptr {
 	 * If it's INVALID_PADDR then it's not set.
 	 */
 	phys_addr_t paddr;
-	bool uptodate;
 };
 
 static void rmw_rbio_work(struct work_struct *work);
@@ -277,13 +276,13 @@ static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
 			 * read from disk.
 			 */
 			if (i < rbio->nr_data * rbio->stripe_nsectors)
-				ASSERT(rbio->stripe_sectors[i].uptodate);
+				ASSERT(test_bit(i, rbio->stripe_uptodate_bitmap));
 			continue;
 		}
 
 		memcpy_sectors(&rbio->stripe_sectors[i], &rbio->bio_sectors[i],
 				rbio->bioc->fs_info->sectorsize);
-		rbio->stripe_sectors[i].uptodate = 1;
+		set_bit(i, rbio->stripe_uptodate_bitmap);
 	}
 	set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
 }
@@ -318,7 +317,7 @@ static __maybe_unused bool full_page_sectors_uptodate(struct btrfs_raid_bio *rbi
 	for (i = sectors_per_page * page_nr;
 	     i < sectors_per_page * page_nr + sectors_per_page;
 	     i++) {
-		if (!rbio->stripe_sectors[i].uptodate)
+		if (!test_bit(i, rbio->stripe_uptodate_bitmap))
 			return false;
 	}
 	return true;
@@ -353,17 +352,14 @@ static void steal_rbio_page(struct btrfs_raid_bio *src,
 {
 	const u32 sectorsize = src->bioc->fs_info->sectorsize;
 	const u32 sectors_per_page = PAGE_SIZE / sectorsize;
-	int i;
 
 	if (dest->stripe_pages[page_nr])
 		__free_page(dest->stripe_pages[page_nr]);
 	dest->stripe_pages[page_nr] = src->stripe_pages[page_nr];
 	src->stripe_pages[page_nr] = NULL;
 
-	/* Also update the sector->uptodate bits. */
-	for (i = sectors_per_page * page_nr;
-	     i < sectors_per_page * page_nr + sectors_per_page; i++)
-		dest->stripe_sectors[i].uptodate = true;
+	/* Also update the stripe_uptodate_bitmap bits. */
+	bitmap_set(dest->stripe_uptodate_bitmap, sectors_per_page * page_nr, sectors_per_page);
 }
 
 static bool is_data_stripe_page(struct btrfs_raid_bio *rbio, int page_nr)
@@ -1031,9 +1027,10 @@ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
 				       GFP_NOFS);
 	rbio->finish_pointers = kcalloc(real_stripes, sizeof(void *), GFP_NOFS);
 	rbio->error_bitmap = bitmap_zalloc(num_sectors, GFP_NOFS);
+	rbio->stripe_uptodate_bitmap = bitmap_zalloc(num_sectors, GFP_NOFS);
 
 	if (!rbio->stripe_pages || !rbio->bio_sectors || !rbio->stripe_sectors ||
-	    !rbio->finish_pointers || !rbio->error_bitmap) {
+	    !rbio->finish_pointers || !rbio->error_bitmap || !rbio->stripe_uptodate_bitmap) {
 		free_raid_bio_pointers(rbio);
 		kfree(rbio);
 		return ERR_PTR(-ENOMEM);
@@ -1331,7 +1328,8 @@ static void generate_pq_vertical(struct btrfs_raid_bio *rbio, int sectornr)
 
 	/* Then add the parity stripe */
 	sector = rbio_pstripe_sector(rbio, sectornr);
-	sector->uptodate = 1;
+	set_bit(rbio_stripe_sector_index(rbio, rbio->nr_data, sectornr),
+		rbio->stripe_uptodate_bitmap);
 	pointers[stripe++] = kmap_local_sector(sector);
 
 	if (has_qstripe) {
@@ -1340,7 +1338,8 @@ static void generate_pq_vertical(struct btrfs_raid_bio *rbio, int sectornr)
 		 * to fill in our p/q
 		 */
 		sector = rbio_qstripe_sector(rbio, sectornr);
-		sector->uptodate = 1;
+		set_bit(rbio_stripe_sector_index(rbio, rbio->nr_data + 1, sectornr),
+			rbio->stripe_uptodate_bitmap);
 		pointers[stripe++] = kmap_local_sector(sector);
 
 		assert_rbio(rbio);
@@ -1496,21 +1495,19 @@ static void set_rbio_range_error(struct btrfs_raid_bio *rbio, struct bio *bio)
 }
 
 /*
- * For subpage case, we can no longer set page Up-to-date directly for
- * stripe_pages[], thus we need to locate the sector.
+ * Return the index inside the rbio->stripe_sectors[] array.
+ *
+ * Return -1 if not found.
  */
-static struct sector_ptr *find_stripe_sector(struct btrfs_raid_bio *rbio,
-					     phys_addr_t paddr)
+static int find_stripe_sector_nr(struct btrfs_raid_bio *rbio, phys_addr_t paddr)
 {
-	int i;
-
-	for (i = 0; i < rbio->nr_sectors; i++) {
+	for (int i = 0; i < rbio->nr_sectors; i++) {
 		struct sector_ptr *sector = &rbio->stripe_sectors[i];
 
 		if (sector->paddr == paddr)
-			return sector;
+			return i;
 	}
-	return NULL;
+	return -1;
 }
 
 /*
@@ -1525,11 +1522,11 @@ static void set_bio_pages_uptodate(struct btrfs_raid_bio *rbio, struct bio *bio)
 	ASSERT(!bio_flagged(bio, BIO_CLONED));
 
 	btrfs_bio_for_each_block_all(paddr, bio, blocksize) {
-		struct sector_ptr *sector = find_stripe_sector(rbio, paddr);
+		int sector_nr = find_stripe_sector_nr(rbio, paddr);
 
-		ASSERT(sector);
-		if (sector)
-			sector->uptodate = 1;
+		ASSERT(sector_nr >= 0);
+		if (sector_nr >= 0)
+			set_bit(sector_nr, rbio->stripe_uptodate_bitmap);
 	}
 }
 
@@ -1963,15 +1960,17 @@ static int recover_vertical(struct btrfs_raid_bio *rbio, int sector_nr,
 			goto cleanup;
 
 		sector = rbio_stripe_sector(rbio, faila, sector_nr);
-		sector->uptodate = 1;
+		set_bit(rbio_stripe_sector_index(rbio, faila, sector_nr),
+			rbio->stripe_uptodate_bitmap);
 	}
 	if (failb >= 0) {
 		ret = verify_one_sector(rbio, failb, sector_nr);
 		if (ret < 0)
 			goto cleanup;
 
 		sector = rbio_stripe_sector(rbio, failb, sector_nr);
-		sector->uptodate = 1;
+		set_bit(rbio_stripe_sector_index(rbio, failb, sector_nr),
+			rbio->stripe_uptodate_bitmap);
 	}
 
 cleanup:
@@ -2325,7 +2324,8 @@ static bool need_read_stripe_sectors(struct btrfs_raid_bio *rbio)
 		 * thus this rbio can not be cached one, as cached one must
 		 * have all its data sectors present and uptodate.
 		 */
-		if (sector->paddr == INVALID_PADDR || !sector->uptodate)
+		if (sector->paddr == INVALID_PADDR ||
+		    !test_bit(i, rbio->stripe_uptodate_bitmap))
 			return true;
 	}
 	return false;
@@ -2551,7 +2551,6 @@ static int finish_parity_scrub(struct btrfs_raid_bio *rbio)
 	if (!page)
 		return -ENOMEM;
 	p_sector.paddr = page_to_phys(page);
-	p_sector.uptodate = 1;
 	page = NULL;
 
 	if (has_qstripe) {
@@ -2563,7 +2562,6 @@ static int finish_parity_scrub(struct btrfs_raid_bio *rbio)
 			return -ENOMEM;
 		}
 		q_sector.paddr = page_to_phys(page);
-		q_sector.uptodate = 1;
 		page = NULL;
 		pointers[rbio->real_stripes - 1] = kmap_local_sector(&q_sector);
 	}
@@ -2781,7 +2779,8 @@ static int scrub_assemble_read_bios(struct btrfs_raid_bio *rbio)
 		 * The bio cache may have handed us an uptodate sector.  If so,
 		 * use it.
 		 */
-		if (sector->uptodate)
+		if (test_bit(rbio_stripe_sector_index(rbio, stripe, sectornr),
+			     rbio->stripe_uptodate_bitmap))
 			continue;
 
 		ret = rbio_add_io_sector(rbio, &bio_list, sector, stripe,
@@ -2899,8 +2898,7 @@ void raid56_parity_cache_data_folios(struct btrfs_raid_bio *rbio,
 			foffset = 0;
 		}
 	}
-	for (unsigned int sector_nr = offset_in_full_stripe >> fs_info->sectorsize_bits;
-	     sector_nr < (offset_in_full_stripe + BTRFS_STRIPE_LEN) >> fs_info->sectorsize_bits;
-	     sector_nr++)
-		rbio->stripe_sectors[sector_nr].uptodate = true;
+	bitmap_set(rbio->stripe_uptodate_bitmap,
+		   offset_in_full_stripe >> fs_info->sectorsize_bits,
+		   BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits);
 }

fs/btrfs/raid56.h

@@ -124,6 +124,9 @@ struct btrfs_raid_bio {
 	 */
 	struct sector_ptr *stripe_sectors;
 
+	/* Each set bit means the corresponding sector in stripe_sectors[] is uptodate. */
+	unsigned long *stripe_uptodate_bitmap;
+
 	/* Allocated with real_stripes-many pointers for finish_*() calls */
 	void **finish_pointers;