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Message-ID: <20240812165931.9106-1-jth@kernel.org>
Date: Mon, 12 Aug 2024 18:59:31 +0200
From: Johannes Thumshirn <jth@...nel.org>
To: Chris Mason <clm@...com>,
Josef Bacik <josef@...icpanda.com>,
David Sterba <dsterba@...e.com>,
linux-btrfs@...r.kernel.org (open list:BTRFS FILE SYSTEM),
linux-kernel@...r.kernel.org (open list)
Cc: Johannes Thumshirn <johannes.thumshirn@....com>
Subject: [PATCH] btrfs: reduce chunk_map lookups in btrfs_map_block
From: Johannes Thumshirn <johannes.thumshirn@....com>
Currently we're calling btrfs_num_copies() before btrfs_get_chunk_map() in
btrfs_map_block(). But btrfs_num_copies() itself does a chunk map lookup
to be able to calculate the number of copies.
So split out the code getting the number of copies from btrfs_num_copies()
into a helper called btrfs_chunk_map_num_copies() and directly call it
from btrfs_map_block() and btrfs_num_copies().
This saves us one rbtree lookup per btrfs_map_block() invocation.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@....com>
---
fs/btrfs/volumes.c | 50 +++++++++++++++++++++++++++-------------------
1 file changed, 29 insertions(+), 21 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e07452207426..4863bdb4d6f4 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5781,10 +5781,33 @@ void btrfs_mapping_tree_free(struct btrfs_fs_info *fs_info)
write_unlock(&fs_info->mapping_tree_lock);
}
+static int btrfs_chunk_map_num_copies(struct btrfs_chunk_map *map)
+{
+ enum btrfs_raid_types index = btrfs_bg_flags_to_raid_index(map->type);
+
+ /* Non-RAID56, use their ncopies from btrfs_raid_array. */
+ if (!(map->type & BTRFS_BLOCK_GROUP_RAID56_MASK))
+ return btrfs_raid_array[index].ncopies;
+
+ if (map->type & BTRFS_BLOCK_GROUP_RAID5)
+ return 2;
+
+ /*
+ * There could be two corrupted data stripes, we need
+ * to loop retry in order to rebuild the correct data.
+ *
+ * Fail a stripe at a time on every retry except the
+ * stripe under reconstruction.
+ */
+ if (map->type & BTRFS_BLOCK_GROUP_RAID6)
+ return map->num_stripes;
+
+ return 1;
+}
+
int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
{
struct btrfs_chunk_map *map;
- enum btrfs_raid_types index;
int ret = 1;
map = btrfs_get_chunk_map(fs_info, logical, len);
@@ -5797,22 +5820,7 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
*/
return 1;
- index = btrfs_bg_flags_to_raid_index(map->type);
-
- /* Non-RAID56, use their ncopies from btrfs_raid_array. */
- if (!(map->type & BTRFS_BLOCK_GROUP_RAID56_MASK))
- ret = btrfs_raid_array[index].ncopies;
- else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
- ret = 2;
- else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
- /*
- * There could be two corrupted data stripes, we need
- * to loop retry in order to rebuild the correct data.
- *
- * Fail a stripe at a time on every retry except the
- * stripe under reconstruction.
- */
- ret = map->num_stripes;
+ ret = btrfs_chunk_map_num_copies(map);
btrfs_free_chunk_map(map);
return ret;
}
@@ -6462,14 +6470,14 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
io_geom.stripe_index = 0;
io_geom.op = op;
- num_copies = btrfs_num_copies(fs_info, logical, fs_info->sectorsize);
- if (io_geom.mirror_num > num_copies)
- return -EINVAL;
-
map = btrfs_get_chunk_map(fs_info, logical, *length);
if (IS_ERR(map))
return PTR_ERR(map);
+ num_copies = btrfs_chunk_map_num_copies(map);
+ if (io_geom.mirror_num > num_copies)
+ return -EINVAL;
+
map_offset = logical - map->start;
io_geom.raid56_full_stripe_start = (u64)-1;
max_len = btrfs_max_io_len(map, map_offset, &io_geom);
--
2.43.0
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