@@ -728,6 +728,98 @@ void btrfs_submit_scrub_read(struct btrfs_fs_info *fs_info,
btrfs_bio_end_io(orig_bbio, ret);
}
+/*
+ * Scrub write special version. Some extra limits:
+ *
+ * - Only support write back for dev-replace and read-repair.
+ * This means, the write bio, even for RAID56, would only
+ * be mapped to single device.
+ *
+ * - @mirror_num must be >0.
+ * To indicate which mirror to be written.
+ * If it's RAID56, it must be 1 (data stripes).
+ *
+ * - The @bbio must not cross stripe boundary.
+ *
+ * - If @dev_replace is true, the resulted stripe must be mapped to
+ * replace source device.
+ *
+ * - No csum geneartion.
+ */
+void btrfs_submit_scrub_write(struct btrfs_fs_info *fs_info,
+ struct btrfs_bio *bbio, int mirror_num,
+ bool dev_replace)
+{
+ struct btrfs_bio *orig_bbio = bbio;
+ u64 logical = bbio->bio.bi_iter.bi_sector << SECTOR_SHIFT;
+ u64 length = bbio->bio.bi_iter.bi_size;
+ u64 map_length = length;
+ struct btrfs_io_context *bioc = NULL;
+ struct btrfs_io_stripe smap;
+ int ret;
+
+ ASSERT(mirror_num > 0);
+ ASSERT(btrfs_op(&bbio->bio) == BTRFS_MAP_WRITE);
+ ASSERT(!bbio->inode);
+
+ bbio->fs_info = fs_info;
+ btrfs_bio_counter_inc_blocked(fs_info);
+ ret = __btrfs_map_block(fs_info, btrfs_op(&bbio->bio), logical,
+ &map_length, &bioc, &smap, &mirror_num, 1);
+ if (ret)
+ goto fail;
+
+ /* Caller should ensure the @bbio doesn't cross stripe boundary. */
+ ASSERT(map_length >= length);
+ if (btrfs_op(&bbio->bio) == BTRFS_MAP_WRITE && btrfs_is_zoned(fs_info)) {
+ bbio->bio.bi_opf &= ~REQ_OP_WRITE;
+ bbio->bio.bi_opf |= REQ_OP_ZONE_APPEND;
+ }
+
+ if (!bioc)
+ goto submit;
+ /* Map the RAID56 multi-stripe writes to a single one. */
+ if (bioc->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
+ int data_stripes = bioc->map_type & BTRFS_BLOCK_GROUP_RAID5 ?
+ bioc->num_stripes - 1 : bioc->num_stripes - 2;
+ int i;
+
+ /* This special write only works for data stripes. */
+ ASSERT(mirror_num == 1);
+ for (i = 0; i < data_stripes; i++) {
+ u64 stripe_start = bioc->full_stripe_logical +
+ (i << BTRFS_STRIPE_LEN_SHIFT);
+
+ if (logical >= stripe_start &&
+ logical < stripe_start + BTRFS_STRIPE_LEN)
+ break;
+ }
+ ASSERT(i < data_stripes);
+ smap.dev = bioc->stripes[i].dev;
+ smap.physical = bioc->stripes[i].physical +
+ ((logical - bioc->full_stripe_logical) &
+ BTRFS_STRIPE_LEN_MASK);
+ goto submit;
+ }
+ ASSERT(mirror_num <= bioc->num_stripes);
+ smap.dev = bioc->stripes[mirror_num - 1].dev;
+ smap.physical = bioc->stripes[mirror_num - 1].physical;
+submit:
+ ASSERT(smap.dev);
+ btrfs_put_bioc(bioc);
+ bioc = NULL;
+ if (dev_replace) {
+ ASSERT(smap.dev == fs_info->dev_replace.srcdev);
+ smap.dev = fs_info->dev_replace.tgtdev;
+ }
+ __btrfs_submit_bio(&bbio->bio, bioc, &smap, mirror_num);
+ return;
+
+fail:
+ btrfs_bio_counter_dec(fs_info);
+ btrfs_bio_end_io(orig_bbio, ret);
+}
+
void btrfs_submit_bio(struct bio *bio, int mirror_num)
{
while (!btrfs_submit_chunk(bio, mirror_num))
@@ -104,6 +104,9 @@ static inline void btrfs_bio_end_io(struct btrfs_bio *bbio, blk_status_t status)
void btrfs_submit_bio(struct bio *bio, int mirror_num);
void btrfs_submit_scrub_read(struct btrfs_fs_info *fs_info,
struct btrfs_bio *bbio, int mirror_num);
+void btrfs_submit_scrub_write(struct btrfs_fs_info *fs_info,
+ struct btrfs_bio *bbio, int mirror_num,
+ bool dev_replace);
int btrfs_repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
u64 length, u64 logical, struct page *page,
unsigned int pg_offset, int mirror_num);
Just like the special scrub read, scrub write also has its extra niches: - Only write back to single device Even for read-repair on RAID56, we only update the corrupted data stripe itself, not triggering the full RMW path. This makes scrub writeback a perfect match for the single stripe quick path. - Requires a valid @mirror_num For RAID56 case, only @mirror_num == 1 is supported. For non-RAID56 cases, we need @mirror_num to locate our stripe. - Need to manually specify if it's for dev-replace For scrub path we can write back to the original device (for read-repair) and to the target device (for replace) at the same time, but with different sectors (read-repair only writes repaired sectors, while dev-replace writes all good sectors). So here we need a bool to specify the case. - No data csum generation Signed-off-by: Qu Wenruo <wqu@suse.com> --- fs/btrfs/bio.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++ fs/btrfs/bio.h | 3 ++ 2 files changed, 95 insertions(+)