btrfs: scrub: introduce a helper to verify one scrub_stripe

The new helper, scrub_verify_stripe(), shares the same main workflow of
the old scrub code.

The major differences are:

- How pages/page_offset is grabbed
  Everything can be grabbed from scrub_stripe easily.

- When error report happens
  Currently the helper only verifies the sectors, not really doing any
  error reporting.
  The error reporting would be done after we have done the repair.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 034d2ad05a929c27c2581e121071a26a0a4833b9..876bc7e3d736e0b49cf0fe748317f477856e5dd7 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2175,7 +2175,7 @@ static unsigned int scrub_stripe_get_page_offset(struct scrub_stripe *stripe,
        return offset_in_page(sector_nr << fs_info->sectorsize_bits);
 }
 
-void scrub_verify_one_metadata(struct scrub_stripe *stripe, int sector_nr)
+static void scrub_verify_one_metadata(struct scrub_stripe *stripe, int sector_nr)
 {
        struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
        const u32 sectors_per_tree = fs_info->nodesize >> fs_info->sectorsize_bits;
@@ -2265,6 +2265,81 @@ void scrub_verify_one_metadata(struct scrub_stripe *stripe, int sector_nr)
        bitmap_clear(&stripe->meta_error_bitmap, sector_nr, sectors_per_tree);
 }
 
+static void scrub_verify_one_sector(struct scrub_stripe *stripe, int sector_nr)
+{
+       struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
+       struct scrub_sector_verification *sector = &stripe->sectors[sector_nr];
+       const u32 sectors_per_tree = fs_info->nodesize >> fs_info->sectorsize_bits;
+       struct page *page = scrub_stripe_get_page(stripe, sector_nr);
+       unsigned int pgoff = scrub_stripe_get_page_offset(stripe, sector_nr);
+       u8 csum_buf[BTRFS_CSUM_SIZE];
+       int ret;
+
+       ASSERT(sector_nr >= 0 && sector_nr < stripe->nr_sectors);
+
+       /* Sector not utilized, skip it. */
+       if (!test_bit(sector_nr, &stripe->extent_sector_bitmap))
+               return;
+
+       /* IO error, no need to check. */
+       if (test_bit(sector_nr, &stripe->io_error_bitmap))
+               return;
+
+       /* Metadata, verify the full tree block. */
+       if (sector->is_metadata) {
+               /*
+                * Check if the tree block crosses the stripe boudary.  If
+                * crossed the boundary, we cannot verify it but only give a
+                * warning.
+                *
+                * This can only happen on a very old filesystem where chunks
+                * are not ensured to be stripe aligned.
+                */
+               if (unlikely(sector_nr + sectors_per_tree > stripe->nr_sectors)) {
+                       btrfs_warn_rl(fs_info,
+                       "tree block at %llu crosses stripe boundary %llu",
+                                     stripe->logical +
+                                     (sector_nr << fs_info->sectorsize_bits),
+                                     stripe->logical);
+                       return;
+               }
+               scrub_verify_one_metadata(stripe, sector_nr);
+               return;
+       }
+
+       /*
+        * Data is easier, we just verify the data csum (if we have it).  For
+        * cases without csum, we have no other choice but to trust it.
+        */
+       if (!sector->csum) {
+               clear_bit(sector_nr, &stripe->error_bitmap);
+               return;
+       }
+
+       ret = btrfs_check_sector_csum(fs_info, page, pgoff, csum_buf, sector->csum);
+       if (ret < 0) {
+               set_bit(sector_nr, &stripe->csum_error_bitmap);
+               set_bit(sector_nr, &stripe->error_bitmap);
+       } else {
+               clear_bit(sector_nr, &stripe->csum_error_bitmap);
+               clear_bit(sector_nr, &stripe->error_bitmap);
+       }
+}
+
+/* Verify specified sectors of a stripe. */
+void scrub_verify_one_stripe(struct scrub_stripe *stripe, unsigned long bitmap)
+{
+       struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
+       const u32 sectors_per_tree = fs_info->nodesize >> fs_info->sectorsize_bits;
+       int sector_nr;
+
+       for_each_set_bit(sector_nr, &bitmap, stripe->nr_sectors) {
+               scrub_verify_one_sector(stripe, sector_nr);
+               if (stripe->sectors[sector_nr].is_metadata)
+                       sector_nr += sectors_per_tree - 1;
+       }
+}
+
 static int scrub_checksum_tree_block(struct scrub_block *sblock)
 {
        struct scrub_ctx *sctx = sblock->sctx;

diff --git a/fs/btrfs/scrub.h b/fs/btrfs/scrub.h
index 0d8bdc7df89c508e3a51f1d14d57f2d326458e1f..45ff7e14980696b1a95c49b3cc71492ead3af51f 100644 (file)
--- a/fs/btrfs/scrub.h
+++ b/fs/btrfs/scrub.h
@@ -24,6 +24,6 @@ int scrub_find_fill_first_stripe(struct btrfs_block_group *bg,
                                 struct btrfs_device *dev, u64 physical,
                                 int mirror_num, u64 logical_start,
                                 u32 logical_len, struct scrub_stripe *stripe);
-void scrub_verify_one_metadata(struct scrub_stripe *stripe, int sector_nr);
+void scrub_verify_one_stripe(struct scrub_stripe *stripe, unsigned long bitmap);
 
 #endif