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btrfs: raid56: make it more explicit that cache rbio should have all its data sectors uptodate

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For Btrfs RAID56, we have a caching system for btrfs raid bios (rbio).

We call cache_rbio_pages() to mark a qualified rbio ready for cache.

The timing happens at:

- finish_rmw()

  At this timing, we have already read all necessary sectors, along with
  the rbio sectors, we have covered all data stripes.

- __raid_recover_end_io()

  At this timing, we have rebuild the rbio, thus all data sectors
  involved (either from stripe or bio list) are uptodate now.

Thus at the timing of cache_rbio_pages(), we should have all data
sectors uptodate.

This patch will make it explicit that all data sectors are uptodate at
cache_rbio_pages() timing, mostly to prepare for the incoming
verification at RMW time.

This patch will add:

- Extra ASSERT()s in cache_rbio_pages()
  This is to make sure all data sectors, which are not covered by bio,
  are already uptodate.

- Extra ASSERT()s in steal_rbio()
  Since only cached rbio can be stolen, thus every data sector should
  already be uptodate in the source rbio.

- Update __raid_recover_end_io() to update recovered sector->uptodate
  Previously __raid_recover_end_io() will only mark failed sectors
  uptodate if it's doing an RMW.

  But this can trigger new ASSERT()s, as for recovery case, a recovered
  failed sector will not be marked uptodate, and trigger ASSERT() in
  later cache_rbio_pages() call.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2022-10-10 18:36:10 +08:00 • committed by David Sterba
parent 797d74b749
commit 88074c8b13
1 changed files with 51 additions and 19 deletions
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70
fs/btrfs/raid56.c
View file

@ -176,8 +176,16 @@ 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].page)
if (!rbio->bio_sectors[i].page) {
/*
* Even if the sector is not covered by bio, if it is
* a data sector it should still be uptodate as it is
* read from disk.
*/
if (i < rbio->nr_data * rbio->stripe_nsectors)
ASSERT(rbio->stripe_sectors[i].uptodate);
continue;
}
ASSERT(rbio->stripe_sectors[i].page);
memcpy_page(rbio->stripe_sectors[i].page,
@ -264,6 +272,21 @@ static void steal_rbio_page(struct btrfs_raid_bio *src,
dest->stripe_sectors[i].uptodate = true;
}
static bool is_data_stripe_page(struct btrfs_raid_bio *rbio, int page_nr)
{
const int sector_nr = (page_nr << PAGE_SHIFT) >>
rbio->bioc->fs_info->sectorsize_bits;
/*
* We have ensured PAGE_SIZE is aligned with sectorsize, thus
* we won't have a page which is half data half parity.
*
* Thus if the first sector of the page belongs to data stripes, then
* the full page belongs to data stripes.
*/
return (sector_nr < rbio->nr_data * rbio->stripe_nsectors);
}
/*
* Stealing an rbio means taking all the uptodate pages from the stripe array
* in the source rbio and putting them into the destination rbio.
@ -274,16 +297,26 @@ static void steal_rbio_page(struct btrfs_raid_bio *src,
static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
{
int i;
struct page *s;
if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
return;
for (i = 0; i < dest->nr_pages; i++) {
s = src->stripe_pages[i];
if (!s || !full_page_sectors_uptodate(src, i))
struct page *p = src->stripe_pages[i];
/*
* We don't need to steal P/Q pages as they will always be
* regenerated for RMW or full write anyway.
*/
if (!is_data_stripe_page(src, i))
continue;
/*
* If @src already has RBIO_CACHE_READY_BIT, it should have
* all data stripe pages present and uptodate.
*/
ASSERT(p);
ASSERT(full_page_sectors_uptodate(src, i));
steal_rbio_page(src, dest, i);
}
index_stripe_sectors(dest);
@ -2003,22 +2036,21 @@ pstripe:
/* xor in the rest */
run_xor(pointers, rbio->nr_data - 1, sectorsize);
}
/* if we're doing this rebuild as part of an rmw, go through
* and set all of our private rbio pages in the
* failed stripes as uptodate. This way finish_rmw will
* know they can be trusted. If this was a read reconstruction,
* other endio functions will fiddle the uptodate bits
/*
* No matter if this is a RMW or recovery, we should have all
* failed sectors repaired, thus they are now uptodate.
* Especially if we determine to cache the rbio, we need to
* have at least all data sectors uptodate.
*/
if (rbio->operation == BTRFS_RBIO_WRITE) {
for (i = 0; i < rbio->stripe_nsectors; i++) {
if (faila != -1) {
sector = rbio_stripe_sector(rbio, faila, i);
sector->uptodate = 1;
}
if (failb != -1) {
sector = rbio_stripe_sector(rbio, failb, i);
sector->uptodate = 1;
}
for (i = 0; i < rbio->stripe_nsectors; i++) {
if (faila != -1) {
sector = rbio_stripe_sector(rbio, faila, i);
sector->uptodate = 1;
}
if (failb != -1) {
sector = rbio_stripe_sector(rbio, failb, i);
sector->uptodate = 1;
}
}
for (stripe = rbio->real_stripes - 1; stripe >= 0; stripe--)