Commit 17d552ab authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: raid56: remove sector_ptr::has_paddr member 



We can use paddr -1 as an indicator for unset/uninitialized paddr.

We can not use 0 paddr, unlike virtual address 0 which is never mapped
thus will always trigger a page fault, physical address 0 may be a valid
page.

So here we follow swiotlb to use (paddr)-1 as a special indicator for
invalid/unset physical address.

Even if the PFN may still be valid, our usage of the physical address
should always be aligned to fs block size (or page size for bs > ps
cases), thus such -1 paddr should never be a valid one.

With this special -1 paddr, we can get rid of has_paddr member and save
1 byte for sector_ptr structure.

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 9b3743a6

fs/btrfs/raid56.c

+26 −20
Original line number Diff line number Diff line
@@ -133,6 +133,12 @@ struct btrfs_stripe_hash_table { 
	struct btrfs_stripe_hash table[];

};



/*

 * The PFN may still be valid, but our paddrs should always be block size

 * aligned, thus such -1 paddr is definitely not a valid one.

 */

#define INVALID_PADDR	(~(phys_addr_t)0)



/*

 * A structure to present a sector inside a page, the length is fixed to

 * sectorsize;
@@ -141,9 +147,10 @@ struct sector_ptr { 
	/*

	 * Blocks from the bio list can still be highmem.

	 * So here we use physical address to present a page and the offset inside it.

	 *

	 * If it's INVALID_PADDR then it's not set.

	 */

	phys_addr_t paddr;

	bool has_paddr;

	bool uptodate;

};
@@ -263,7 +270,7 @@ static void cache_rbio_pages(struct btrfs_raid_bio *rbio) 


	for (i = 0; i < rbio->nr_sectors; i++) {

		/* Some range not covered by bio (partial write), skip it */

		if (!rbio->bio_sectors[i].has_paddr) {

		if (rbio->bio_sectors[i].paddr == INVALID_PADDR) {

			/*

			 * Even if the sector is not covered by bio, if it is

			 * a data sector it should still be uptodate as it is
@@ -335,7 +342,6 @@ static void index_stripe_sectors(struct btrfs_raid_bio *rbio) 
		if (!rbio->stripe_pages[page_index])

			continue;



		rbio->stripe_sectors[i].has_paddr = true;

		rbio->stripe_sectors[i].paddr =

			page_to_phys(rbio->stripe_pages[page_index]) +

			offset_in_page(offset);
@@ -972,9 +978,9 @@ static struct sector_ptr *sector_in_rbio(struct btrfs_raid_bio *rbio, 


	spin_lock(&rbio->bio_list_lock);

	sector = &rbio->bio_sectors[index];

	if (sector->has_paddr || bio_list_only) {

	if (sector->paddr != INVALID_PADDR || bio_list_only) {

		/* Don't return sector without a valid page pointer */

		if (!sector->has_paddr)

		if (sector->paddr == INVALID_PADDR)

			sector = NULL;

		spin_unlock(&rbio->bio_list_lock);

		return sector;
@@ -1032,6 +1038,10 @@ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info, 
		kfree(rbio);

		return ERR_PTR(-ENOMEM);

	}

	for (int i = 0; i < num_sectors; i++) {

		rbio->stripe_sectors[i].paddr = INVALID_PADDR;

		rbio->bio_sectors[i].paddr = INVALID_PADDR;

	}



	bio_list_init(&rbio->bio_list);

	init_waitqueue_head(&rbio->io_wait);
@@ -1152,7 +1162,7 @@ static int rbio_add_io_sector(struct btrfs_raid_bio *rbio, 
			   rbio, stripe_nr);

	ASSERT_RBIO_SECTOR(sector_nr >= 0 && sector_nr < rbio->stripe_nsectors,

			   rbio, sector_nr);

	ASSERT(sector->has_paddr);

	ASSERT(sector->paddr != INVALID_PADDR);



	stripe = &rbio->bioc->stripes[stripe_nr];

	disk_start = stripe->physical + sector_nr * sectorsize;
@@ -1216,7 +1226,6 @@ static void index_one_bio(struct btrfs_raid_bio *rbio, struct bio *bio) 
		unsigned int index = (offset >> sectorsize_bits);

		struct sector_ptr *sector = &rbio->bio_sectors[index];



		sector->has_paddr = true;

		sector->paddr = paddr;

		offset += sectorsize;

	}
@@ -1299,7 +1308,7 @@ static void assert_rbio(struct btrfs_raid_bio *rbio) 
static inline void *kmap_local_sector(const struct sector_ptr *sector)

{

	/* The sector pointer must have a page mapped to it. */

	ASSERT(sector->has_paddr);

	ASSERT(sector->paddr != INVALID_PADDR);



	return kmap_local_page(phys_to_page(sector->paddr)) +

	       offset_in_page(sector->paddr);
@@ -1498,7 +1507,7 @@ static struct sector_ptr *find_stripe_sector(struct btrfs_raid_bio *rbio, 
	for (i = 0; i < rbio->nr_sectors; i++) {

		struct sector_ptr *sector = &rbio->stripe_sectors[i];



		if (sector->has_paddr && sector->paddr == paddr)

		if (sector->paddr == paddr)

			return sector;

	}

	return NULL;
@@ -1532,8 +1541,7 @@ static int get_bio_sector_nr(struct btrfs_raid_bio *rbio, struct bio *bio) 
	for (i = 0; i < rbio->nr_sectors; i++) {

		if (rbio->stripe_sectors[i].paddr == bvec_paddr)

			break;

		if (rbio->bio_sectors[i].has_paddr &&

		    rbio->bio_sectors[i].paddr == bvec_paddr)

		if (rbio->bio_sectors[i].paddr == bvec_paddr)

			break;

	}

	ASSERT(i < rbio->nr_sectors);
@@ -2317,7 +2325,7 @@ 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->has_paddr || !sector->uptodate)

		if (sector->paddr == INVALID_PADDR || !sector->uptodate)

			return true;

	}

	return false;
@@ -2508,8 +2516,8 @@ static int finish_parity_scrub(struct btrfs_raid_bio *rbio) 
	int sectornr;

	bool has_qstripe;

	struct page *page;

	struct sector_ptr p_sector = { 0 };

	struct sector_ptr q_sector = { 0 };

	struct sector_ptr p_sector = { .paddr = INVALID_PADDR };

	struct sector_ptr q_sector = { .paddr = INVALID_PADDR };

	struct bio_list bio_list;

	int is_replace = 0;

	int ret;
@@ -2542,7 +2550,6 @@ static int finish_parity_scrub(struct btrfs_raid_bio *rbio) 
	page = alloc_page(GFP_NOFS);

	if (!page)

		return -ENOMEM;

	p_sector.has_paddr = true;

	p_sector.paddr = page_to_phys(page);

	p_sector.uptodate = 1;

	page = NULL;
@@ -2552,10 +2559,9 @@ static int finish_parity_scrub(struct btrfs_raid_bio *rbio) 
		page = alloc_page(GFP_NOFS);

		if (!page) {

			__free_page(phys_to_page(p_sector.paddr));

			p_sector.has_paddr = false;

			p_sector.paddr = INVALID_PADDR;

			return -ENOMEM;

		}

		q_sector.has_paddr = true;

		q_sector.paddr = page_to_phys(page);

		q_sector.uptodate = 1;

		page = NULL;
@@ -2604,10 +2610,10 @@ static int finish_parity_scrub(struct btrfs_raid_bio *rbio) 


	kunmap_local(pointers[nr_data]);

	__free_page(phys_to_page(p_sector.paddr));

	p_sector.has_paddr = false;

	if (q_sector.has_paddr) {

	p_sector.paddr = INVALID_PADDR;

	if (q_sector.paddr != INVALID_PADDR) {

		__free_page(phys_to_page(q_sector.paddr));

		q_sector.has_paddr = false;

		q_sector.paddr = INVALID_PADDR;

	}



	/*