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From:   Johannes Thumshirn <johannes.thumshirn@wdc.com>
Date:   Wed, 13 Dec 2023 06:43:01 -0800
Subject: [PATCH v2 06/13] btrfs: factor out block mapping for RAID10
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Message-Id: <20231213-btrfs_map_block-cleanup-v2-6-cf5cfb9e2400@wdc.com>
References: <20231213-btrfs_map_block-cleanup-v2-0-cf5cfb9e2400@wdc.com>
In-Reply-To: <20231213-btrfs_map_block-cleanup-v2-0-cf5cfb9e2400@wdc.com>
To:     Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
        David Sterba <dsterba@suse.com>
Cc:     linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org,
        Johannes Thumshirn <johannes.thumshirn@wdc.com>
Precedence: bulk

Now that we have a container for the I/O geometry that has all the needed
information for the block mappings of RAID10, factor out a helper calculating
this information.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 fs/btrfs/volumes.c | 48 +++++++++++++++++++++++++++++++-----------------
 1 file changed, 31 insertions(+), 17 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index fe2807bb0935..4c9c130cdfd0 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6408,6 +6408,35 @@ static void map_blocks_dup(struct btrfs_chunk_map *map,
 	io_geom->mirror_num = 1;
 }
 
+static void map_blocks_raid10(struct btrfs_fs_info *fs_info,
+				  struct btrfs_chunk_map *map,
+				  struct btrfs_io_geometry *io_geom,
+				  bool dev_replace_is_ongoing)
+{
+	u32 factor = map->num_stripes / map->sub_stripes;
+	int old_stripe_index;
+
+	io_geom->stripe_index =
+		(io_geom->stripe_nr % factor) * map->sub_stripes;
+	io_geom->stripe_nr /= factor;
+
+	if (io_geom->op != BTRFS_MAP_READ) {
+		io_geom->num_stripes = map->sub_stripes;
+		return;
+	}
+
+	if (io_geom->mirror_num) {
+		io_geom->stripe_index += io_geom->mirror_num - 1;
+		return;
+	}
+
+	old_stripe_index = io_geom->stripe_index;
+	io_geom->stripe_index = find_live_mirror(fs_info, map,
+						 io_geom->stripe_index,
+						 dev_replace_is_ongoing);
+	io_geom->mirror_num = io_geom->stripe_index - old_stripe_index + 1;
+}
+
 /*
  * Map one logical range to one or more physical ranges.
  *
@@ -6502,23 +6531,8 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 	} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
 		map_blocks_dup(map, &io_geom);
 	} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
-		u32 factor = map->num_stripes / map->sub_stripes;
-
-		io_geom.stripe_index = (io_geom.stripe_nr % factor) * map->sub_stripes;
-		io_geom.stripe_nr /= factor;
-
-		if (op != BTRFS_MAP_READ)
-			io_geom.num_stripes = map->sub_stripes;
-		else if (io_geom.mirror_num)
-			io_geom.stripe_index += io_geom.mirror_num - 1;
-		else {
-			int old_stripe_index = io_geom.stripe_index;
-			io_geom.stripe_index = find_live_mirror(fs_info, map,
-					      io_geom.stripe_index,
-					      dev_replace_is_ongoing);
-			io_geom.mirror_num = io_geom.stripe_index - old_stripe_index + 1;
-		}
-
+		map_blocks_raid10(fs_info, map, &io_geom,
+				  dev_replace_is_ongoing);
 	} else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
 		if (op != BTRFS_MAP_READ || io_geom.mirror_num > 1) {
 			/*

-- 
2.43.0