btrfs: raid56: make raid56_add_scrub_pages() subpage compatible

This requires one extra parameter @pgoff for the function.

In the current code base, scrub is still one page per sector, thus the
new parameter will always be 0.

It needs the extra subpage scrub optimization code to fully take
advantage.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/raid56.c

@@ -2381,17 +2381,19 @@ struct btrfs_raid_bio *raid56_parity_alloc_scrub_rbio(struct bio *bio,
 
 /* Used for both parity scrub and missing. */
 void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,
-			    u64 logical)
+			    unsigned int pgoff, u64 logical)
 {
+	const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
 	int stripe_offset;
 	int index;
 
 	ASSERT(logical >= rbio->bioc->raid_map[0]);
-	ASSERT(logical + PAGE_SIZE <= rbio->bioc->raid_map[0] +
+	ASSERT(logical + sectorsize <= rbio->bioc->raid_map[0] +
 				rbio->stripe_len * rbio->nr_data);
 	stripe_offset = (int)(logical - rbio->bioc->raid_map[0]);
-	index = stripe_offset >> PAGE_SHIFT;
-	rbio->bio_pages[index] = page;
+	index = stripe_offset / sectorsize;
+	rbio->bio_sectors[index].page = page;
+	rbio->bio_sectors[index].pgoff = pgoff;
 }
 
 /*

fs/btrfs/raid56.h

@@ -35,7 +35,7 @@ int raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
 int raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc, u32 stripe_len);
 
 void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,
-			    u64 logical);
+			    unsigned int pgoff, u64 logical);
 
 struct btrfs_raid_bio *raid56_parity_alloc_scrub_rbio(struct bio *bio,
 				struct btrfs_io_context *bioc, u32 stripe_len,

fs/btrfs/scrub.c

@@ -2205,7 +2205,11 @@ static void scrub_missing_raid56_pages(struct scrub_block *sblock)
 	for (i = 0; i < sblock->sector_count; i++) {
 		struct scrub_sector *sector = sblock->sectors[i];
 
-		raid56_add_scrub_pages(rbio, sector->page, sector->logical);
+		/*
+		 * For now, our scrub is still one page per sector, so pgoff
+		 * is always 0.
+		 */
+		raid56_add_scrub_pages(rbio, sector->page, 0, sector->logical);
 	}
 
 	btrfs_init_work(&sblock->work, scrub_missing_raid56_worker, NULL, NULL);