From 4886ff7b50f6341539611a1503a6ad2e55b77c98 Mon Sep 17 00:00:00 2001
From: Qu Wenruo <wqu@suse.com>
Date: Mon, 20 Mar 2023 10:12:49 +0800
Subject: btrfs: introduce a new helper to submit write bio for repair
Both scrub and read-repair are utilizing a special repair writes that:
- Only writes back to a single device
Even for read-repair on RAID56, we only update the corrupted data
stripe itself, not triggering the full RMW path.
- Requires a valid @mirror_num
For RAID56 case, only @mirror_num == 1 is valid.
For non-RAID56 cases, we need @mirror_num to locate our stripe.
- No data csum generation needed
These two call sites still have some differences though:
- Read-repair goes plain bio
It doesn't need a full btrfs_bio, and goes submit_bio_wait().
- New scrub repair would go btrfs_bio
To simplify both read and write path.
So here this patch would:
- Introduce a common helper, btrfs_map_repair_block()
Due to the single device nature, we can use an on-stack
btrfs_io_stripe to pass device and its physical bytenr.
- Introduce a new interface, btrfs_submit_repair_bio(), for later scrub
code
This is for the incoming scrub code.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/raid56.h | 5 +++++
1 file changed, 5 insertions(+)
(limited to 'fs/btrfs/raid56.h')
diff --git a/fs/btrfs/raid56.h b/fs/btrfs/raid56.h
index df0e0abdeb1f..6583c225b1bd 100644
--- a/fs/btrfs/raid56.h
+++ b/fs/btrfs/raid56.h
@@ -170,6 +170,11 @@ static inline int nr_data_stripes(const struct map_lookup *map)
return map->num_stripes - btrfs_nr_parity_stripes(map->type);
}
+static inline int nr_bioc_data_stripes(const struct btrfs_io_context *bioc)
+{
+ return bioc->num_stripes - btrfs_nr_parity_stripes(bioc->map_type);
+}
+
#define RAID5_P_STRIPE ((u64)-2)
#define RAID6_Q_STRIPE ((u64)-1)
--
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