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btrfs: reduce chunk_map lookups in btrfs_map_block()

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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.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Johannes Thumshirn 2024-08-13 13:36:40 +02:00 committed by David Sterba
parent 6d752cacae
commit 0ae653fbec
1 changed files with 27 additions and 22 deletions
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49
fs/btrfs/volumes.c
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@ -5781,11 +5781,31 @@ 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(const struct btrfs_chunk_map *map)
{
enum btrfs_raid_types index = btrfs_bg_flags_to_raid_index(map->type);
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;
/* Non-RAID56, use their ncopies from btrfs_raid_array. */
return btrfs_raid_array[index].ncopies;
}
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;
int ret;
map = btrfs_get_chunk_map(fs_info, logical, len);
if (IS_ERR(map))
@ -5797,22 +5817,7 @@ 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 +6467,14 @@ 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);