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btrfs: optimize simple reads in btrfsic_map_block

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Pass a smap into __btrfs_map_block so that the usual case of a read that
doesn't require parity raid recovery doesn't need an extra memory
allocation for the btrfs_io_context.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Christoph Hellwig 2023-05-31 06:17:35 +02:00 • committed by David Sterba
parent 3965a4c793
commit 78a213a05d
1 changed files with 12 additions and 7 deletions
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19
fs/btrfs/check-integrity.c
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@ -1459,13 +1459,13 @@ static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
struct btrfs_fs_info *fs_info = state->fs_info;
int ret;
u64 length;
struct btrfs_io_context *multi = NULL;
struct btrfs_io_context *bioc = NULL;
struct btrfs_io_stripe smap, *map;
struct btrfs_device *device;
length = len;
ret = btrfs_map_block(fs_info, BTRFS_MAP_READ,
bytenr, &length, &multi, mirror_num);
ret = __btrfs_map_block(fs_info, BTRFS_MAP_READ, bytenr, &length, &bioc,
NULL, &mirror_num, 0);
if (ret) {
block_ctx_out->start = 0;
block_ctx_out->dev_bytenr = 0;
@ -1478,21 +1478,26 @@ static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
return ret;
}
device = multi->stripes[0].dev;
if (bioc)
map = &bioc->stripes[0];
else
map = &smap;
device = map->dev;
if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state) ||
!device->bdev || !device->name)
block_ctx_out->dev = NULL;
else
block_ctx_out->dev = btrfsic_dev_state_lookup(
device->bdev->bd_dev);
block_ctx_out->dev_bytenr = multi->stripes[0].physical;
block_ctx_out->dev_bytenr = map->physical;
block_ctx_out->start = bytenr;
block_ctx_out->len = len;
block_ctx_out->datav = NULL;
block_ctx_out->pagev = NULL;
block_ctx_out->mem_to_free = NULL;
kfree(multi);
kfree(bioc);
if (NULL == block_ctx_out->dev) {
ret = -ENXIO;
pr_info("btrfsic: error, cannot lookup dev (#1)!\n");