#include "fs.h"
#include "accessors.h"
#include "extent-tree.h"
+#include "zoned.h"
/*
* HOW DOES SPACE RESERVATION WORK
* churn a lot and we can avoid making some extent tree modifications if we
* are able to delay for as long as possible.
*
+ * RESET_ZONES
+ * This state works only for the zoned mode. On the zoned mode, we cannot
+ * reuse once allocated then freed region until we reset the zone, due to
+ * the sequential write zone requirement. The RESET_ZONES state resets the
+ * zones of an unused block group and let us reuse the space. The reusing
+ * is faster than removing the block group and allocating another block
+ * group on the zones.
+ *
* ALLOC_CHUNK
* We will skip this the first time through space reservation, because of
* overcommit and we don't want to have a lot of useless metadata space when
*/
ret = btrfs_commit_current_transaction(root);
break;
+ case RESET_ZONES:
+ ret = btrfs_reset_unused_block_groups(space_info, num_bytes);
+ break;
default:
ret = -ENOSPC;
break;
enum btrfs_flush_state flush_state;
int commit_cycles = 0;
u64 last_tickets_id;
+ enum btrfs_flush_state final_state;
fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
+ if (btrfs_is_zoned(fs_info))
+ final_state = RESET_ZONES;
+ else
+ final_state = COMMIT_TRANS;
spin_lock(&space_info->lock);
to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info);
if (flush_state == ALLOC_CHUNK_FORCE && !commit_cycles)
flush_state++;
- if (flush_state > COMMIT_TRANS) {
+ if (flush_state > final_state) {
commit_cycles++;
if (commit_cycles > 2) {
if (maybe_fail_all_tickets(fs_info, space_info)) {
}
}
spin_unlock(&space_info->lock);
- } while (flush_state <= COMMIT_TRANS);
+ } while (flush_state <= final_state);
}
/*
* This is where we reclaim all of the pinned space generated by running the
* iputs
*
+ * RESET_ZONES
+ * This state works only for the zoned mode. We scan the unused block group
+ * list and reset the zones and reuse the block group.
+ *
* ALLOC_CHUNK_FORCE
* For data we start with alloc chunk force, however we could have been full
* before, and then the transaction commit could have freed new block groups,
FLUSH_DELALLOC_FULL,
RUN_DELAYED_IPUTS,
COMMIT_TRANS,
+ RESET_ZONES,
ALLOC_CHUNK_FORCE,
};
static const enum btrfs_flush_state priority_flush_states[] = {
FLUSH_DELAYED_ITEMS_NR,
FLUSH_DELAYED_ITEMS,
+ RESET_ZONES,
ALLOC_CHUNK,
};
FLUSH_DELALLOC_FULL,
ALLOC_CHUNK,
COMMIT_TRANS,
+ RESET_ZONES,
};
static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
}
spin_unlock(&fs_info->zone_active_bgs_lock);
}
+
+/*
+ * Reset the zones of unused block groups from @space_info->bytes_zone_unusable.
+ *
+ * @space_info: the space to work on
+ * @num_bytes: targeting reclaim bytes
+ *
+ * This one resets the zones of a block group, so we can reuse the region
+ * without removing the block group. On the other hand, btrfs_delete_unused_bgs()
+ * just removes a block group and frees up the underlying zones. So, we still
+ * need to allocate a new block group to reuse the zones.
+ *
+ * Resetting is faster than deleting/recreating a block group. It is similar
+ * to freeing the logical space on the regular mode. However, we cannot change
+ * the block group's profile with this operation.
+ */
+int btrfs_reset_unused_block_groups(struct btrfs_space_info *space_info, u64 num_bytes)
+{
+ struct btrfs_fs_info *fs_info = space_info->fs_info;
+ const sector_t zone_size_sectors = fs_info->zone_size >> SECTOR_SHIFT;
+
+ if (!btrfs_is_zoned(fs_info))
+ return 0;
+
+ while (num_bytes > 0) {
+ struct btrfs_chunk_map *map;
+ struct btrfs_block_group *bg = NULL;
+ bool found = false;
+ u64 reclaimed = 0;
+
+ /*
+ * Here, we choose a fully zone_unusable block group. It's
+ * technically possible to reset a partly zone_unusable block
+ * group, which still has some free space left. However,
+ * handling that needs to cope with the allocation side, which
+ * makes the logic more complex. So, let's handle the easy case
+ * for now.
+ */
+ spin_lock(&fs_info->unused_bgs_lock);
+ list_for_each_entry(bg, &fs_info->unused_bgs, bg_list) {
+ if ((bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) != space_info->flags)
+ continue;
+
+ /*
+ * Use trylock to avoid locking order violation. In
+ * btrfs_reclaim_bgs_work(), the lock order is
+ * &bg->lock -> &fs_info->unused_bgs_lock. We skip a
+ * block group if we cannot take its lock.
+ */
+ if (!spin_trylock(&bg->lock))
+ continue;
+ if (btrfs_is_block_group_used(bg) || bg->zone_unusable < bg->length) {
+ spin_unlock(&bg->lock);
+ continue;
+ }
+ spin_unlock(&bg->lock);
+ found = true;
+ break;
+ }
+ if (!found) {
+ spin_unlock(&fs_info->unused_bgs_lock);
+ return 0;
+ }
+
+ list_del_init(&bg->bg_list);
+ btrfs_put_block_group(bg);
+ spin_unlock(&fs_info->unused_bgs_lock);
+
+ /*
+ * Since the block group is fully zone_unusable and we cannot
+ * allocate from this block group anymore, we don't need to set
+ * this block group read-only.
+ */
+
+ down_read(&fs_info->dev_replace.rwsem);
+ map = bg->physical_map;
+ for (int i = 0; i < map->num_stripes; i++) {
+ struct btrfs_io_stripe *stripe = &map->stripes[i];
+ unsigned int nofs_flags;
+ int ret;
+
+ nofs_flags = memalloc_nofs_save();
+ ret = blkdev_zone_mgmt(stripe->dev->bdev, REQ_OP_ZONE_RESET,
+ stripe->physical >> SECTOR_SHIFT,
+ zone_size_sectors);
+ memalloc_nofs_restore(nofs_flags);
+
+ if (ret) {
+ up_read(&fs_info->dev_replace.rwsem);
+ return ret;
+ }
+ }
+ up_read(&fs_info->dev_replace.rwsem);
+
+ spin_lock(&space_info->lock);
+ spin_lock(&bg->lock);
+ ASSERT(!btrfs_is_block_group_used(bg));
+ if (bg->ro) {
+ spin_unlock(&bg->lock);
+ spin_unlock(&space_info->lock);
+ continue;
+ }
+
+ reclaimed = bg->alloc_offset;
+ bg->zone_unusable = bg->length - bg->zone_capacity;
+ bg->alloc_offset = 0;
+ /*
+ * This holds because we currently reset fully used then freed
+ * block group.
+ */
+ ASSERT(reclaimed == bg->zone_capacity);
+ bg->free_space_ctl->free_space += reclaimed;
+ space_info->bytes_zone_unusable -= reclaimed;
+ spin_unlock(&bg->lock);
+ btrfs_return_free_space(space_info, reclaimed);
+ spin_unlock(&space_info->lock);
+
+ if (num_bytes <= reclaimed)
+ break;
+ num_bytes -= reclaimed;
+ }
+
+ return 0;
+}
projects / thirdparty / linux.git / commitdiff
