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btrfs: raid56: remove sector_ptr::has_paddr member

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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: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2025-10-09 15:09:59 +10:30 committed by David Sterba
parent 9b3743a676
commit 17d552ab9b
1 changed files with 26 additions and 20 deletions
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46
fs/btrfs/raid56.c
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@ -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;
}
/*