On Mon, Sep 11, 2023 at 05:52:07AM -0700, Johannes Thumshirn wrote:
> A filesystem that uses the RAID stripe tree for logical to physical
> address translation can't use the regular scrub path, that reads all
> stripes and then checks if a sector is unused afterwards.
>
> When using the RAID stripe tree, this will result in lookup errors, as the
> stripe tree doesn't know the requested logical addresses.
>
> Instead, look up stripes that are backed by the extent bitmap.
>
> Signed-off-by: Johannes Thumshirn <[email protected]>
> ---
> fs/btrfs/scrub.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 56 insertions(+)
>
> diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
> index f16220ce5fba..5101e0a3f83e 100644
> --- a/fs/btrfs/scrub.c
> +++ b/fs/btrfs/scrub.c
> @@ -23,6 +23,7 @@
> #include "accessors.h"
> #include "file-item.h"
> #include "scrub.h"
> +#include "raid-stripe-tree.h"
>
> /*
> * This is only the first step towards a full-features scrub. It reads all
> @@ -1634,6 +1635,56 @@ static void scrub_reset_stripe(struct scrub_stripe *stripe)
> }
> }
>
> +static void scrub_submit_extent_sector_read(struct scrub_ctx *sctx,
> + struct scrub_stripe *stripe)
> +{
> + struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
> + struct btrfs_bio *bbio = NULL;
> + int mirror = stripe->mirror_num;
> + int i;
> +
> + atomic_inc(&stripe->pending_io);
> +
> + for_each_set_bit(i, &stripe->extent_sector_bitmap, stripe->nr_sectors) {
> + struct page *page;
> + int pgoff;
This should be unsigned int.
> +
> + page = scrub_stripe_get_page(stripe, i);
> + pgoff = scrub_stripe_get_page_offset(stripe, i);
You can probably move the initializations right to the declarations, I
think we have that elsewhere too.
> + /* The current sector cannot be merged, submit the bio. */
> + if (bbio &&
> + ((i > 0 && !test_bit(i - 1, &stripe->extent_sector_bitmap)) ||
> + bbio->bio.bi_iter.bi_size >= BTRFS_STRIPE_LEN)) {
> + ASSERT(bbio->bio.bi_iter.bi_size);
> + atomic_inc(&stripe->pending_io);
> + btrfs_submit_bio(bbio, mirror);
> + bbio = NULL;
> + }
> +
> + if (!bbio) {
> + bbio = btrfs_bio_alloc(stripe->nr_sectors, REQ_OP_READ,
> + fs_info, scrub_read_endio, stripe);
> + bbio->bio.bi_iter.bi_sector = (stripe->logical +
> + (i << fs_info->sectorsize_bits)) >> SECTOR_SHIFT;
> + }
> +
> + __bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff);
> + }
> +
> + if (bbio) {
> + ASSERT(bbio->bio.bi_iter.bi_size);
> + atomic_inc(&stripe->pending_io);
> + btrfs_submit_bio(bbio, mirror);
> + }
> +
> + if (atomic_dec_and_test(&stripe->pending_io)) {
> + wake_up(&stripe->io_wait);
> + INIT_WORK(&stripe->work, scrub_stripe_read_repair_worker);
> + queue_work(stripe->bg->fs_info->scrub_workers, &stripe->work);
> + }
> +}