diff options
Diffstat (limited to '')
| -rw-r--r-- | fs/btrfs/block-group.c | 4232 |
1 files changed, 4232 insertions, 0 deletions
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c new file mode 100644 index 000000000..08017b180 --- /dev/null +++ b/fs/btrfs/block-group.c @@ -0,0 +1,4232 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/list_sort.h> +#include "misc.h" +#include "ctree.h" +#include "block-group.h" +#include "space-info.h" +#include "disk-io.h" +#include "free-space-cache.h" +#include "free-space-tree.h" +#include "volumes.h" +#include "transaction.h" +#include "ref-verify.h" +#include "sysfs.h" +#include "tree-log.h" +#include "delalloc-space.h" +#include "discard.h" +#include "raid56.h" +#include "zoned.h" + +/* + * Return target flags in extended format or 0 if restripe for this chunk_type + * is not in progress + * + * Should be called with balance_lock held + */ +static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags) +{ + struct btrfs_balance_control *bctl = fs_info->balance_ctl; + u64 target = 0; + + if (!bctl) + return 0; + + if (flags & BTRFS_BLOCK_GROUP_DATA && + bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) { + target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target; + } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM && + bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) { + target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target; + } else if (flags & BTRFS_BLOCK_GROUP_METADATA && + bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) { + target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target; + } + + return target; +} + +/* + * @flags: available profiles in extended format (see ctree.h) + * + * Return reduced profile in chunk format. If profile changing is in progress + * (either running or paused) picks the target profile (if it's already + * available), otherwise falls back to plain reducing. + */ +static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags) +{ + u64 num_devices = fs_info->fs_devices->rw_devices; + u64 target; + u64 raid_type; + u64 allowed = 0; + + /* + * See if restripe for this chunk_type is in progress, if so try to + * reduce to the target profile + */ + spin_lock(&fs_info->balance_lock); + target = get_restripe_target(fs_info, flags); + if (target) { + spin_unlock(&fs_info->balance_lock); + return extended_to_chunk(target); + } + spin_unlock(&fs_info->balance_lock); + + /* First, mask out the RAID levels which aren't possible */ + for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) { + if (num_devices >= btrfs_raid_array[raid_type].devs_min) + allowed |= btrfs_raid_array[raid_type].bg_flag; + } + allowed &= flags; + + /* Select the highest-redundancy RAID level. */ + if (allowed & BTRFS_BLOCK_GROUP_RAID1C4) + allowed = BTRFS_BLOCK_GROUP_RAID1C4; + else if (allowed & BTRFS_BLOCK_GROUP_RAID6) + allowed = BTRFS_BLOCK_GROUP_RAID6; + else if (allowed & BTRFS_BLOCK_GROUP_RAID1C3) + allowed = BTRFS_BLOCK_GROUP_RAID1C3; + else if (allowed & BTRFS_BLOCK_GROUP_RAID5) + allowed = BTRFS_BLOCK_GROUP_RAID5; + else if (allowed & BTRFS_BLOCK_GROUP_RAID10) + allowed = BTRFS_BLOCK_GROUP_RAID10; + else if (allowed & BTRFS_BLOCK_GROUP_RAID1) + allowed = BTRFS_BLOCK_GROUP_RAID1; + else if (allowed & BTRFS_BLOCK_GROUP_DUP) + allowed = BTRFS_BLOCK_GROUP_DUP; + else if (allowed & BTRFS_BLOCK_GROUP_RAID0) + allowed = BTRFS_BLOCK_GROUP_RAID0; + + flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK; + + return extended_to_chunk(flags | allowed); +} + +u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags) +{ + unsigned seq; + u64 flags; + + do { + flags = orig_flags; + seq = read_seqbegin(&fs_info->profiles_lock); + + if (flags & BTRFS_BLOCK_GROUP_DATA) + flags |= fs_info->avail_data_alloc_bits; + else if (flags & BTRFS_BLOCK_GROUP_SYSTEM) + flags |= fs_info->avail_system_alloc_bits; + else if (flags & BTRFS_BLOCK_GROUP_METADATA) + flags |= fs_info->avail_metadata_alloc_bits; + } while (read_seqretry(&fs_info->profiles_lock, seq)); + + return btrfs_reduce_alloc_profile(fs_info, flags); +} + +void btrfs_get_block_group(struct btrfs_block_group *cache) +{ + refcount_inc(&cache->refs); +} + +void btrfs_put_block_group(struct btrfs_block_group *cache) +{ + if (refcount_dec_and_test(&cache->refs)) { + WARN_ON(cache->pinned > 0); + /* + * If there was a failure to cleanup a log tree, very likely due + * to an IO failure on a writeback attempt of one or more of its + * extent buffers, we could not do proper (and cheap) unaccounting + * of their reserved space, so don't warn on reserved > 0 in that + * case. + */ + if (!(cache->flags & BTRFS_BLOCK_GROUP_METADATA) || + !BTRFS_FS_LOG_CLEANUP_ERROR(cache->fs_info)) + WARN_ON(cache->reserved > 0); + + /* + * A block_group shouldn't be on the discard_list anymore. + * Remove the block_group from the discard_list to prevent us + * from causing a panic due to NULL pointer dereference. + */ + if (WARN_ON(!list_empty(&cache->discard_list))) + btrfs_discard_cancel_work(&cache->fs_info->discard_ctl, + cache); + + /* + * If not empty, someone is still holding mutex of + * full_stripe_lock, which can only be released by caller. + * And it will definitely cause use-after-free when caller + * tries to release full stripe lock. + * + * No better way to resolve, but only to warn. + */ + WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root)); + kfree(cache->free_space_ctl); + kfree(cache->physical_map); + kfree(cache); + } +} + +/* + * This adds the block group to the fs_info rb tree for the block group cache + */ +static int btrfs_add_block_group_cache(struct btrfs_fs_info *info, + struct btrfs_block_group *block_group) +{ + struct rb_node **p; + struct rb_node *parent = NULL; + struct btrfs_block_group *cache; + bool leftmost = true; + + ASSERT(block_group->length != 0); + + write_lock(&info->block_group_cache_lock); + p = &info->block_group_cache_tree.rb_root.rb_node; + + while (*p) { + parent = *p; + cache = rb_entry(parent, struct btrfs_block_group, cache_node); + if (block_group->start < cache->start) { + p = &(*p)->rb_left; + } else if (block_group->start > cache->start) { + p = &(*p)->rb_right; + leftmost = false; + } else { + write_unlock(&info->block_group_cache_lock); + return -EEXIST; + } + } + + rb_link_node(&block_group->cache_node, parent, p); + rb_insert_color_cached(&block_group->cache_node, + &info->block_group_cache_tree, leftmost); + + write_unlock(&info->block_group_cache_lock); + + return 0; +} + +/* + * This will return the block group at or after bytenr if contains is 0, else + * it will return the block group that contains the bytenr + */ +static struct btrfs_block_group *block_group_cache_tree_search( + struct btrfs_fs_info *info, u64 bytenr, int contains) +{ + struct btrfs_block_group *cache, *ret = NULL; + struct rb_node *n; + u64 end, start; + + read_lock(&info->block_group_cache_lock); + n = info->block_group_cache_tree.rb_root.rb_node; + + while (n) { + cache = rb_entry(n, struct btrfs_block_group, cache_node); + end = cache->start + cache->length - 1; + start = cache->start; + + if (bytenr < start) { + if (!contains && (!ret || start < ret->start)) + ret = cache; + n = n->rb_left; + } else if (bytenr > start) { + if (contains && bytenr <= end) { + ret = cache; + break; + } + n = n->rb_right; + } else { + ret = cache; + break; + } + } + if (ret) + btrfs_get_block_group(ret); + read_unlock(&info->block_group_cache_lock); + + return ret; +} + +/* + * Return the block group that starts at or after bytenr + */ +struct btrfs_block_group *btrfs_lookup_first_block_group( + struct btrfs_fs_info *info, u64 bytenr) +{ + return block_group_cache_tree_search(info, bytenr, 0); +} + +/* + * Return the block group that contains the given bytenr + */ +struct btrfs_block_group *btrfs_lookup_block_group( + struct btrfs_fs_info *info, u64 bytenr) +{ + return block_group_cache_tree_search(info, bytenr, 1); +} + +struct btrfs_block_group *btrfs_next_block_group( + struct btrfs_block_group *cache) +{ + struct btrfs_fs_info *fs_info = cache->fs_info; + struct rb_node *node; + + read_lock(&fs_info->block_group_cache_lock); + + /* If our block group was removed, we need a full search. */ + if (RB_EMPTY_NODE(&cache->cache_node)) { + const u64 next_bytenr = cache->start + cache->length; + + read_unlock(&fs_info->block_group_cache_lock); + btrfs_put_block_group(cache); + return btrfs_lookup_first_block_group(fs_info, next_bytenr); + } + node = rb_next(&cache->cache_node); + btrfs_put_block_group(cache); + if (node) { + cache = rb_entry(node, struct btrfs_block_group, cache_node); + btrfs_get_block_group(cache); + } else + cache = NULL; + read_unlock(&fs_info->block_group_cache_lock); + return cache; +} + +/** + * Check if we can do a NOCOW write for a given extent. + * + * @fs_info: The filesystem information object. + * @bytenr: Logical start address of the extent. + * + * Check if we can do a NOCOW write for the given extent, and increments the + * number of NOCOW writers in the block group that contains the extent, as long + * as the block group exists and it's currently not in read-only mode. + * + * Returns: A non-NULL block group pointer if we can do a NOCOW write, the caller + * is responsible for calling btrfs_dec_nocow_writers() later. + * + * Or NULL if we can not do a NOCOW write + */ +struct btrfs_block_group *btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, + u64 bytenr) +{ + struct btrfs_block_group *bg; + bool can_nocow = true; + + bg = btrfs_lookup_block_group(fs_info, bytenr); + if (!bg) + return NULL; + + spin_lock(&bg->lock); + if (bg->ro) + can_nocow = false; + else + atomic_inc(&bg->nocow_writers); + spin_unlock(&bg->lock); + + if (!can_nocow) { + btrfs_put_block_group(bg); + return NULL; + } + + /* No put on block group, done by btrfs_dec_nocow_writers(). */ + return bg; +} + +/** + * Decrement the number of NOCOW writers in a block group. + * + * @bg: The block group. + * + * This is meant to be called after a previous call to btrfs_inc_nocow_writers(), + * and on the block group returned by that call. Typically this is called after + * creating an ordered extent for a NOCOW write, to prevent races with scrub and + * relocation. + * + * After this call, the caller should not use the block group anymore. It it wants + * to use it, then it should get a reference on it before calling this function. + */ +void btrfs_dec_nocow_writers(struct btrfs_block_group *bg) +{ + if (atomic_dec_and_test(&bg->nocow_writers)) + wake_up_var(&bg->nocow_writers); + + /* For the lookup done by a previous call to btrfs_inc_nocow_writers(). */ + btrfs_put_block_group(bg); +} + +void btrfs_wait_nocow_writers(struct btrfs_block_group *bg) +{ + wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers)); +} + +void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info, + const u64 start) +{ + struct btrfs_block_group *bg; + + bg = btrfs_lookup_block_group(fs_info, start); + ASSERT(bg); + if (atomic_dec_and_test(&bg->reservations)) + wake_up_var(&bg->reservations); + btrfs_put_block_group(bg); +} + +void btrfs_wait_block_group_reservations(struct btrfs_block_group *bg) +{ + struct btrfs_space_info *space_info = bg->space_info; + + ASSERT(bg->ro); + + if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA)) + return; + + /* + * Our block group is read only but before we set it to read only, + * some task might have had allocated an extent from it already, but it + * has not yet created a respective ordered extent (and added it to a + * root's list of ordered extents). + * Therefore wait for any task currently allocating extents, since the + * block group's reservations counter is incremented while a read lock + * on the groups' semaphore is held and decremented after releasing + * the read access on that semaphore and creating the ordered extent. + */ + down_write(&space_info->groups_sem); + up_write(&space_info->groups_sem); + + wait_var_event(&bg->reservations, !atomic_read(&bg->reservations)); +} + +struct btrfs_caching_control *btrfs_get_caching_control( + struct btrfs_block_group *cache) +{ + struct btrfs_caching_control *ctl; + + spin_lock(&cache->lock); + if (!cache->caching_ctl) { + spin_unlock(&cache->lock); + return NULL; + } + + ctl = cache->caching_ctl; + refcount_inc(&ctl->count); + spin_unlock(&cache->lock); + return ctl; +} + +void btrfs_put_caching_control(struct btrfs_caching_control *ctl) +{ + if (refcount_dec_and_test(&ctl->count)) + kfree(ctl); +} + +/* + * When we wait for progress in the block group caching, its because our + * allocation attempt failed at least once. So, we must sleep and let some + * progress happen before we try again. + * + * This function will sleep at least once waiting for new free space to show + * up, and then it will check the block group free space numbers for our min + * num_bytes. Another option is to have it go ahead and look in the rbtree for + * a free extent of a given size, but this is a good start. + * + * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using + * any of the information in this block group. + */ +void btrfs_wait_block_group_cache_progress(struct btrfs_block_group *cache, + u64 num_bytes) +{ + struct btrfs_caching_control *caching_ctl; + int progress; + + caching_ctl = btrfs_get_caching_control(cache); + if (!caching_ctl) + return; + + /* + * We've already failed to allocate from this block group, so even if + * there's enough space in the block group it isn't contiguous enough to + * allow for an allocation, so wait for at least the next wakeup tick, + * or for the thing to be done. + */ + progress = atomic_read(&caching_ctl->progress); + + wait_event(caching_ctl->wait, btrfs_block_group_done(cache) || + (progress != atomic_read(&caching_ctl->progress) && + (cache->free_space_ctl->free_space >= num_bytes))); + + btrfs_put_caching_control(caching_ctl); +} + +static int btrfs_caching_ctl_wait_done(struct btrfs_block_group *cache, + struct btrfs_caching_control *caching_ctl) +{ + wait_event(caching_ctl->wait, btrfs_block_group_done(cache)); + return cache->cached == BTRFS_CACHE_ERROR ? -EIO : 0; +} + +static int btrfs_wait_block_group_cache_done(struct btrfs_block_group *cache) +{ + struct btrfs_caching_control *caching_ctl; + int ret; + + caching_ctl = btrfs_get_caching_control(cache); + if (!caching_ctl) + return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0; + ret = btrfs_caching_ctl_wait_done(cache, caching_ctl); + btrfs_put_caching_control(caching_ctl); + return ret; +} + +#ifdef CONFIG_BTRFS_DEBUG +static void fragment_free_space(struct btrfs_block_group *block_group) +{ + struct btrfs_fs_info *fs_info = block_group->fs_info; + u64 start = block_group->start; + u64 len = block_group->length; + u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ? + fs_info->nodesize : fs_info->sectorsize; + u64 step = chunk << 1; + + while (len > chunk) { + btrfs_remove_free_space(block_group, start, chunk); + start += step; + if (len < step) + len = 0; + else + len -= step; + } +} +#endif + +/* + * This is only called by btrfs_cache_block_group, since we could have freed + * extents we need to check the pinned_extents for any extents that can't be + * used yet since their free space will be released as soon as the transaction + * commits. + */ +int add_new_free_space(struct btrfs_block_group *block_group, u64 start, u64 end, + u64 *total_added_ret) +{ + struct btrfs_fs_info *info = block_group->fs_info; + u64 extent_start, extent_end, size; + int ret; + + if (total_added_ret) + *total_added_ret = 0; + + while (start < end) { + ret = find_first_extent_bit(&info->excluded_extents, start, + &extent_start, &extent_end, + EXTENT_DIRTY | EXTENT_UPTODATE, + NULL); + if (ret) + break; + + if (extent_start <= start) { + start = extent_end + 1; + } else if (extent_start > start && extent_start < end) { + size = extent_start - start; + ret = btrfs_add_free_space_async_trimmed(block_group, + start, size); + if (ret) + return ret; + if (total_added_ret) + *total_added_ret += size; + start = extent_end + 1; + } else { + break; + } + } + + if (start < end) { + size = end - start; + ret = btrfs_add_free_space_async_trimmed(block_group, start, + size); + if (ret) + return ret; + if (total_added_ret) + *total_added_ret += size; + } + + return 0; +} + +static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl) +{ + struct btrfs_block_group *block_group = caching_ctl->block_group; + struct btrfs_fs_info *fs_info = block_group->fs_info; + struct btrfs_root *extent_root; + struct btrfs_path *path; + struct extent_buffer *leaf; + struct btrfs_key key; + u64 total_found = 0; + u64 last = 0; + u32 nritems; + int ret; + bool wakeup = true; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + last = max_t(u64, block_group->start, BTRFS_SUPER_INFO_OFFSET); + extent_root = btrfs_extent_root(fs_info, last); + +#ifdef CONFIG_BTRFS_DEBUG + /* + * If we're fragmenting we don't want to make anybody think we can + * allocate from this block group until we've had a chance to fragment + * the free space. + */ + if (btrfs_should_fragment_free_space(block_group)) + wakeup = false; +#endif + /* + * We don't want to deadlock with somebody trying to allocate a new + * extent for the extent root while also trying to search the extent + * root to add free space. So we skip locking and search the commit + * root, since its read-only + */ + path->skip_locking = 1; + path->search_commit_root = 1; + path->reada = READA_FORWARD; + + key.objectid = last; + key.offset = 0; + key.type = BTRFS_EXTENT_ITEM_KEY; + +next: + ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0); + if (ret < 0) + goto out; + + leaf = path->nodes[0]; + nritems = btrfs_header_nritems(leaf); + + while (1) { + if (btrfs_fs_closing(fs_info) > 1) { + last = (u64)-1; + break; + } + + if (path->slots[0] < nritems) { + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + } else { + ret = btrfs_find_next_key(extent_root, path, &key, 0, 0); + if (ret) + break; + + if (need_resched() || + rwsem_is_contended(&fs_info->commit_root_sem)) { + btrfs_release_path(path); + up_read(&fs_info->commit_root_sem); + mutex_unlock(&caching_ctl->mutex); + cond_resched(); + mutex_lock(&caching_ctl->mutex); + down_read(&fs_info->commit_root_sem); + goto next; + } + + ret = btrfs_next_leaf(extent_root, path); + if (ret < 0) + goto out; + if (ret) + break; + leaf = path->nodes[0]; + nritems = btrfs_header_nritems(leaf); + continue; + } + + if (key.objectid < last) { + key.objectid = last; + key.offset = 0; + key.type = BTRFS_EXTENT_ITEM_KEY; + btrfs_release_path(path); + goto next; + } + + if (key.objectid < block_group->start) { + path->slots[0]++; + continue; + } + + if (key.objectid >= block_group->start + block_group->length) + break; + + if (key.type == BTRFS_EXTENT_ITEM_KEY || + key.type == BTRFS_METADATA_ITEM_KEY) { + u64 space_added; + + ret = add_new_free_space(block_group, last, key.objectid, + &space_added); + if (ret) + goto out; + total_found += space_added; + if (key.type == BTRFS_METADATA_ITEM_KEY) + last = key.objectid + + fs_info->nodesize; + else + last = key.objectid + key.offset; + + if (total_found > CACHING_CTL_WAKE_UP) { + total_found = 0; + if (wakeup) { + atomic_inc(&caching_ctl->progress); + wake_up(&caching_ctl->wait); + } + } + } + path->slots[0]++; + } + + ret = add_new_free_space(block_group, last, + block_group->start + block_group->length, + NULL); +out: + btrfs_free_path(path); + return ret; +} + +static noinline void caching_thread(struct btrfs_work *work) +{ + struct btrfs_block_group *block_group; + struct btrfs_fs_info *fs_info; + struct btrfs_caching_control *caching_ctl; + int ret; + + caching_ctl = container_of(work, struct btrfs_caching_control, work); + block_group = caching_ctl->block_group; + fs_info = block_group->fs_info; + + mutex_lock(&caching_ctl->mutex); + down_read(&fs_info->commit_root_sem); + + if (btrfs_test_opt(fs_info, SPACE_CACHE)) { + ret = load_free_space_cache(block_group); + if (ret == 1) { + ret = 0; + goto done; + } + + /* + * We failed to load the space cache, set ourselves to + * CACHE_STARTED and carry on. + */ + spin_lock(&block_group->lock); + block_group->cached = BTRFS_CACHE_STARTED; + spin_unlock(&block_group->lock); + wake_up(&caching_ctl->wait); + } + + /* + * If we are in the transaction that populated the free space tree we + * can't actually cache from the free space tree as our commit root and + * real root are the same, so we could change the contents of the blocks + * while caching. Instead do the slow caching in this case, and after + * the transaction has committed we will be safe. + */ + if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) && + !(test_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags))) + ret = load_free_space_tree(caching_ctl); + else + ret = load_extent_tree_free(caching_ctl); +done: + spin_lock(&block_group->lock); + block_group->caching_ctl = NULL; + block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED; + spin_unlock(&block_group->lock); + +#ifdef CONFIG_BTRFS_DEBUG + if (btrfs_should_fragment_free_space(block_group)) { + u64 bytes_used; + + spin_lock(&block_group->space_info->lock); + spin_lock(&block_group->lock); + bytes_used = block_group->length - block_group->used; + block_group->space_info->bytes_used += bytes_used >> 1; + spin_unlock(&block_group->lock); + spin_unlock(&block_group->space_info->lock); + fragment_free_space(block_group); + } +#endif + + up_read(&fs_info->commit_root_sem); + btrfs_free_excluded_extents(block_group); + mutex_unlock(&caching_ctl->mutex); + + wake_up(&caching_ctl->wait); + + btrfs_put_caching_control(caching_ctl); + btrfs_put_block_group(block_group); +} + +int btrfs_cache_block_group(struct btrfs_block_group *cache, bool wait) +{ + struct btrfs_fs_info *fs_info = cache->fs_info; + struct btrfs_caching_control *caching_ctl = NULL; + int ret = 0; + + /* Allocator for zoned filesystems does not use the cache at all */ + if (btrfs_is_zoned(fs_info)) + return 0; + + caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS); + if (!caching_ctl) + return -ENOMEM; + + INIT_LIST_HEAD(&caching_ctl->list); + mutex_init(&caching_ctl->mutex); + init_waitqueue_head(&caching_ctl->wait); + caching_ctl->block_group = cache; + refcount_set(&caching_ctl->count, 2); + atomic_set(&caching_ctl->progress, 0); + btrfs_init_work(&caching_ctl->work, caching_thread, NULL, NULL); + + spin_lock(&cache->lock); + if (cache->cached != BTRFS_CACHE_NO) { + kfree(caching_ctl); + + caching_ctl = cache->caching_ctl; + if (caching_ctl) + refcount_inc(&caching_ctl->count); + spin_unlock(&cache->lock); + goto out; + } + WARN_ON(cache->caching_ctl); + cache->caching_ctl = caching_ctl; + cache->cached = BTRFS_CACHE_STARTED; + spin_unlock(&cache->lock); + + write_lock(&fs_info->block_group_cache_lock); + refcount_inc(&caching_ctl->count); + list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups); + write_unlock(&fs_info->block_group_cache_lock); + + btrfs_get_block_group(cache); + + btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work); +out: + if (wait && caching_ctl) + ret = btrfs_caching_ctl_wait_done(cache, caching_ctl); + if (caching_ctl) + btrfs_put_caching_control(caching_ctl); + + return ret; +} + +static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags) +{ + u64 extra_flags = chunk_to_extended(flags) & + BTRFS_EXTENDED_PROFILE_MASK; + + write_seqlock(&fs_info->profiles_lock); + if (flags & BTRFS_BLOCK_GROUP_DATA) + fs_info->avail_data_alloc_bits &= ~extra_flags; + if (flags & BTRFS_BLOCK_GROUP_METADATA) + fs_info->avail_metadata_alloc_bits &= ~extra_flags; + if (flags & BTRFS_BLOCK_GROUP_SYSTEM) + fs_info->avail_system_alloc_bits &= ~extra_flags; + write_sequnlock(&fs_info->profiles_lock); +} + +/* + * Clear incompat bits for the following feature(s): + * + * - RAID56 - in case there's neither RAID5 nor RAID6 profile block group + * in the whole filesystem + * + * - RAID1C34 - same as above for RAID1C3 and RAID1C4 block groups + */ +static void clear_incompat_bg_bits(struct btrfs_fs_info *fs_info, u64 flags) +{ + bool found_raid56 = false; + bool found_raid1c34 = false; + + if ((flags & BTRFS_BLOCK_GROUP_RAID56_MASK) || + (flags & BTRFS_BLOCK_GROUP_RAID1C3) || + (flags & BTRFS_BLOCK_GROUP_RAID1C4)) { + struct list_head *head = &fs_info->space_info; + struct btrfs_space_info *sinfo; + + list_for_each_entry_rcu(sinfo, head, list) { + down_read(&sinfo->groups_sem); + if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID5])) + found_raid56 = true; + if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID6])) + found_raid56 = true; + if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C3])) + found_raid1c34 = true; + if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C4])) + found_raid1c34 = true; + up_read(&sinfo->groups_sem); + } + if (!found_raid56) + btrfs_clear_fs_incompat(fs_info, RAID56); + if (!found_raid1c34) + btrfs_clear_fs_incompat(fs_info, RAID1C34); + } +} + +static int remove_block_group_item(struct btrfs_trans_handle *trans, + struct btrfs_path *path, + struct btrfs_block_group *block_group) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_root *root; + struct btrfs_key key; + int ret; + + root = btrfs_block_group_root(fs_info); + key.objectid = block_group->start; + key.type = BTRFS_BLOCK_GROUP_ITEM_KEY; + key.offset = block_group->length; + + ret = btrfs_search_slot(trans, root, &key, path, -1, 1); + if (ret > 0) + ret = -ENOENT; + if (ret < 0) + return ret; + + ret = btrfs_del_item(trans, root, path); + return ret; +} + +int btrfs_remove_block_group(struct btrfs_trans_handle *trans, + u64 group_start, struct extent_map *em) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_path *path; + struct btrfs_block_group *block_group; + struct btrfs_free_cluster *cluster; + struct inode *inode; + struct kobject *kobj = NULL; + int ret; + int index; + int factor; + struct btrfs_caching_control *caching_ctl = NULL; + bool remove_em; + bool remove_rsv = false; + + block_group = btrfs_lookup_block_group(fs_info, group_start); + BUG_ON(!block_group); + BUG_ON(!block_group->ro); + + trace_btrfs_remove_block_group(block_group); + /* + * Free the reserved super bytes from this block group before + * remove it. + */ + btrfs_free_excluded_extents(block_group); + btrfs_free_ref_tree_range(fs_info, block_group->start, + block_group->length); + + index = btrfs_bg_flags_to_raid_index(block_group->flags); + factor = btrfs_bg_type_to_factor(block_group->flags); + + /* make sure this block group isn't part of an allocation cluster */ + cluster = &fs_info->data_alloc_cluster; + spin_lock(&cluster->refill_lock); + btrfs_return_cluster_to_free_space(block_group, cluster); + spin_unlock(&cluster->refill_lock); + + /* + * make sure this block group isn't part of a metadata + * allocation cluster + */ + cluster = &fs_info->meta_alloc_cluster; + spin_lock(&cluster->refill_lock); + btrfs_return_cluster_to_free_space(block_group, cluster); + spin_unlock(&cluster->refill_lock); + + btrfs_clear_treelog_bg(block_group); + btrfs_clear_data_reloc_bg(block_group); + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + + /* + * get the inode first so any iput calls done for the io_list + * aren't the final iput (no unlinks allowed now) + */ + inode = lookup_free_space_inode(block_group, path); + + mutex_lock(&trans->transaction->cache_write_mutex); + /* + * Make sure our free space cache IO is done before removing the + * free space inode + */ + spin_lock(&trans->transaction->dirty_bgs_lock); + if (!list_empty(&block_group->io_list)) { + list_del_init(&block_group->io_list); + + WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode); + + spin_unlock(&trans->transaction->dirty_bgs_lock); + btrfs_wait_cache_io(trans, block_group, path); + btrfs_put_block_group(block_group); + spin_lock(&trans->transaction->dirty_bgs_lock); + } + + if (!list_empty(&block_group->dirty_list)) { + list_del_init(&block_group->dirty_list); + remove_rsv = true; + btrfs_put_block_group(block_group); + } + spin_unlock(&trans->transaction->dirty_bgs_lock); + mutex_unlock(&trans->transaction->cache_write_mutex); + + ret = btrfs_remove_free_space_inode(trans, inode, block_group); + if (ret) + goto out; + + write_lock(&fs_info->block_group_cache_lock); + rb_erase_cached(&block_group->cache_node, + &fs_info->block_group_cache_tree); + RB_CLEAR_NODE(&block_group->cache_node); + + /* Once for the block groups rbtree */ + btrfs_put_block_group(block_group); + + write_unlock(&fs_info->block_group_cache_lock); + + down_write(&block_group->space_info->groups_sem); + /* + * we must use list_del_init so people can check to see if they + * are still on the list after taking the semaphore + */ + list_del_init(&block_group->list); + if (list_empty(&block_group->space_info->block_groups[index])) { + kobj = block_group->space_info->block_group_kobjs[index]; + block_group->space_info->block_group_kobjs[index] = NULL; + clear_avail_alloc_bits(fs_info, block_group->flags); + } + up_write(&block_group->space_info->groups_sem); + clear_incompat_bg_bits(fs_info, block_group->flags); + if (kobj) { + kobject_del(kobj); + kobject_put(kobj); + } + + if (block_group->cached == BTRFS_CACHE_STARTED) + btrfs_wait_block_group_cache_done(block_group); + + write_lock(&fs_info->block_group_cache_lock); + caching_ctl = btrfs_get_caching_control(block_group); + if (!caching_ctl) { + struct btrfs_caching_control *ctl; + + list_for_each_entry(ctl, &fs_info->caching_block_groups, list) { + if (ctl->block_group == block_group) { + caching_ctl = ctl; + refcount_inc(&caching_ctl->count); + break; + } + } + } + if (caching_ctl) + list_del_init(&caching_ctl->list); + write_unlock(&fs_info->block_group_cache_lock); + + if (caching_ctl) { + /* Once for the caching bgs list and once for us. */ + btrfs_put_caching_control(caching_ctl); + btrfs_put_caching_control(caching_ctl); + } + + spin_lock(&trans->transaction->dirty_bgs_lock); + WARN_ON(!list_empty(&block_group->dirty_list)); + WARN_ON(!list_empty(&block_group->io_list)); + spin_unlock(&trans->transaction->dirty_bgs_lock); + + btrfs_remove_free_space_cache(block_group); + + spin_lock(&block_group->space_info->lock); + list_del_init(&block_group->ro_list); + + if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) { + WARN_ON(block_group->space_info->total_bytes + < block_group->length); + WARN_ON(block_group->space_info->bytes_readonly + < block_group->length - block_group->zone_unusable); + WARN_ON(block_group->space_info->bytes_zone_unusable + < block_group->zone_unusable); + WARN_ON(block_group->space_info->disk_total + < block_group->length * factor); + WARN_ON(test_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE, + &block_group->runtime_flags) && + block_group->space_info->active_total_bytes + < block_group->length); + } + block_group->space_info->total_bytes -= block_group->length; + if (test_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE, &block_group->runtime_flags)) + block_group->space_info->active_total_bytes -= block_group->length; + block_group->space_info->bytes_readonly -= + (block_group->length - block_group->zone_unusable); + block_group->space_info->bytes_zone_unusable -= + block_group->zone_unusable; + block_group->space_info->disk_total -= block_group->length * factor; + + spin_unlock(&block_group->space_info->lock); + + /* + * Remove the free space for the block group from the free space tree + * and the block group's item from the extent tree before marking the + * block group as removed. This is to prevent races with tasks that + * freeze and unfreeze a block group, this task and another task + * allocating a new block group - the unfreeze task ends up removing + * the block group's extent map before the task calling this function + * deletes the block group item from the extent tree, allowing for + * another task to attempt to create another block group with the same + * item key (and failing with -EEXIST and a transaction abort). + */ + ret = remove_block_group_free_space(trans, block_group); + if (ret) + goto out; + + ret = remove_block_group_item(trans, path, block_group); + if (ret < 0) + goto out; + + spin_lock(&block_group->lock); + set_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags); + + /* + * At this point trimming or scrub can't start on this block group, + * because we removed the block group from the rbtree + * fs_info->block_group_cache_tree so no one can't find it anymore and + * even if someone already got this block group before we removed it + * from the rbtree, they have already incremented block_group->frozen - + * if they didn't, for the trimming case they won't find any free space + * entries because we already removed them all when we called + * btrfs_remove_free_space_cache(). + * + * And we must not remove the extent map from the fs_info->mapping_tree + * to prevent the same logical address range and physical device space + * ranges from being reused for a new block group. This is needed to + * avoid races with trimming and scrub. + * + * An fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is + * completely transactionless, so while it is trimming a range the + * currently running transaction might finish and a new one start, + * allowing for new block groups to be created that can reuse the same + * physical device locations unless we take this special care. + * + * There may also be an implicit trim operation if the file system + * is mounted with -odiscard. The same protections must remain + * in place until the extents have been discarded completely when + * the transaction commit has completed. + */ + remove_em = (atomic_read(&block_group->frozen) == 0); + spin_unlock(&block_group->lock); + + if (remove_em) { + struct extent_map_tree *em_tree; + + em_tree = &fs_info->mapping_tree; + write_lock(&em_tree->lock); + remove_extent_mapping(em_tree, em); + write_unlock(&em_tree->lock); + /* once for the tree */ + free_extent_map(em); + } + +out: + /* Once for the lookup reference */ + btrfs_put_block_group(block_group); + if (remove_rsv) + btrfs_delayed_refs_rsv_release(fs_info, 1); + btrfs_free_path(path); + return ret; +} + +struct btrfs_trans_handle *btrfs_start_trans_remove_block_group( + struct btrfs_fs_info *fs_info, const u64 chunk_offset) +{ + struct btrfs_root *root = btrfs_block_group_root(fs_info); + struct extent_map_tree *em_tree = &fs_info->mapping_tree; + struct extent_map *em; + struct map_lookup *map; + unsigned int num_items; + + read_lock(&em_tree->lock); + em = lookup_extent_mapping(em_tree, chunk_offset, 1); + read_unlock(&em_tree->lock); + ASSERT(em && em->start == chunk_offset); + + /* + * We need to reserve 3 + N units from the metadata space info in order + * to remove a block group (done at btrfs_remove_chunk() and at + * btrfs_remove_block_group()), which are used for: + * + * 1 unit for adding the free space inode's orphan (located in the tree + * of tree roots). + * 1 unit for deleting the block group item (located in the extent + * tree). + * 1 unit for deleting the free space item (located in tree of tree + * roots). + * N units for deleting N device extent items corresponding to each + * stripe (located in the device tree). + * + * In order to remove a block group we also need to reserve units in the + * system space info in order to update the chunk tree (update one or + * more device items and remove one chunk item), but this is done at + * btrfs_remove_chunk() through a call to check_system_chunk(). + */ + map = em->map_lookup; + num_items = 3 + map->num_stripes; + free_extent_map(em); + + return btrfs_start_transaction_fallback_global_rsv(root, num_items); +} + +/* + * Mark block group @cache read-only, so later write won't happen to block + * group @cache. + * + * If @force is not set, this function will only mark the block group readonly + * if we have enough free space (1M) in other metadata/system block groups. + * If @force is not set, this function will mark the block group readonly + * without checking free space. + * + * NOTE: This function doesn't care if other block groups can contain all the + * data in this block group. That check should be done by relocation routine, + * not this function. + */ +static int inc_block_group_ro(struct btrfs_block_group *cache, int force) +{ + struct btrfs_space_info *sinfo = cache->space_info; + u64 num_bytes; + int ret = -ENOSPC; + + spin_lock(&sinfo->lock); + spin_lock(&cache->lock); + + if (cache->swap_extents) { + ret = -ETXTBSY; + goto out; + } + + if (cache->ro) { + cache->ro++; + ret = 0; + goto out; + } + + num_bytes = cache->length - cache->reserved - cache->pinned - + cache->bytes_super - cache->zone_unusable - cache->used; + + /* + * Data never overcommits, even in mixed mode, so do just the straight + * check of left over space in how much we have allocated. + */ + if (force) { + ret = 0; + } else if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA) { + u64 sinfo_used = btrfs_space_info_used(sinfo, true); + + /* + * Here we make sure if we mark this bg RO, we still have enough + * free space as buffer. + */ + if (sinfo_used + num_bytes <= sinfo->total_bytes) + ret = 0; + } else { + /* + * We overcommit metadata, so we need to do the + * btrfs_can_overcommit check here, and we need to pass in + * BTRFS_RESERVE_NO_FLUSH to give ourselves the most amount of + * leeway to allow us to mark this block group as read only. + */ + if (btrfs_can_overcommit(cache->fs_info, sinfo, num_bytes, + BTRFS_RESERVE_NO_FLUSH)) + ret = 0; + } + + if (!ret) { + sinfo->bytes_readonly += num_bytes; + if (btrfs_is_zoned(cache->fs_info)) { + /* Migrate zone_unusable bytes to readonly */ + sinfo->bytes_readonly += cache->zone_unusable; + sinfo->bytes_zone_unusable -= cache->zone_unusable; + cache->zone_unusable = 0; + } + cache->ro++; + list_add_tail(&cache->ro_list, &sinfo->ro_bgs); + } +out: + spin_unlock(&cache->lock); + spin_unlock(&sinfo->lock); + if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) { + btrfs_info(cache->fs_info, + "unable to make block group %llu ro", cache->start); + btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0); + } + return ret; +} + +static bool clean_pinned_extents(struct btrfs_trans_handle *trans, + struct btrfs_block_group *bg) +{ + struct btrfs_fs_info *fs_info = bg->fs_info; + struct btrfs_transaction *prev_trans = NULL; + const u64 start = bg->start; + const u64 end = start + bg->length - 1; + int ret; + + spin_lock(&fs_info->trans_lock); + if (trans->transaction->list.prev != &fs_info->trans_list) { + prev_trans = list_last_entry(&trans->transaction->list, + struct btrfs_transaction, list); + refcount_inc(&prev_trans->use_count); + } + spin_unlock(&fs_info->trans_lock); + + /* + * Hold the unused_bg_unpin_mutex lock to avoid racing with + * btrfs_finish_extent_commit(). If we are at transaction N, another + * task might be running finish_extent_commit() for the previous + * transaction N - 1, and have seen a range belonging to the block + * group in pinned_extents before we were able to clear the whole block + * group range from pinned_extents. This means that task can lookup for + * the block group after we unpinned it from pinned_extents and removed + * it, leading to a BUG_ON() at unpin_extent_range(). + */ + mutex_lock(&fs_info->unused_bg_unpin_mutex); + if (prev_trans) { + ret = clear_extent_bits(&prev_trans->pinned_extents, start, end, + EXTENT_DIRTY); + if (ret) + goto out; + } + + ret = clear_extent_bits(&trans->transaction->pinned_extents, start, end, + EXTENT_DIRTY); +out: + mutex_unlock(&fs_info->unused_bg_unpin_mutex); + if (prev_trans) + btrfs_put_transaction(prev_trans); + + return ret == 0; +} + +/* + * Process the unused_bgs list and remove any that don't have any allocated + * space inside of them. + */ +void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info) +{ + struct btrfs_block_group *block_group; + struct btrfs_space_info *space_info; + struct btrfs_trans_handle *trans; + const bool async_trim_enabled = btrfs_test_opt(fs_info, DISCARD_ASYNC); + int ret = 0; + + if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags)) + return; + + if (btrfs_fs_closing(fs_info)) + return; + + /* + * Long running balances can keep us blocked here for eternity, so + * simply skip deletion if we're unable to get the mutex. + */ + if (!mutex_trylock(&fs_info->reclaim_bgs_lock)) + return; + + spin_lock(&fs_info->unused_bgs_lock); + while (!list_empty(&fs_info->unused_bgs)) { + int trimming; + + block_group = list_first_entry(&fs_info->unused_bgs, + struct btrfs_block_group, + bg_list); + list_del_init(&block_group->bg_list); + + space_info = block_group->space_info; + + if (ret || btrfs_mixed_space_info(space_info)) { + btrfs_put_block_group(block_group); + continue; + } + spin_unlock(&fs_info->unused_bgs_lock); + + btrfs_discard_cancel_work(&fs_info->discard_ctl, block_group); + + /* Don't want to race with allocators so take the groups_sem */ + down_write(&space_info->groups_sem); + + /* + * Async discard moves the final block group discard to be prior + * to the unused_bgs code path. Therefore, if it's not fully + * trimmed, punt it back to the async discard lists. + */ + if (btrfs_test_opt(fs_info, DISCARD_ASYNC) && + !btrfs_is_free_space_trimmed(block_group)) { + trace_btrfs_skip_unused_block_group(block_group); + up_write(&space_info->groups_sem); + /* Requeue if we failed because of async discard */ + btrfs_discard_queue_work(&fs_info->discard_ctl, + block_group); + goto next; + } + + spin_lock(&block_group->lock); + if (block_group->reserved || block_group->pinned || + block_group->used || block_group->ro || + list_is_singular(&block_group->list)) { + /* + * We want to bail if we made new allocations or have + * outstanding allocations in this block group. We do + * the ro check in case balance is currently acting on + * this block group. + */ + trace_btrfs_skip_unused_block_group(block_group); + spin_unlock(&block_group->lock); + up_write(&space_info->groups_sem); + goto next; + } + spin_unlock(&block_group->lock); + + /* We don't want to force the issue, only flip if it's ok. */ + ret = inc_block_group_ro(block_group, 0); + up_write(&space_info->groups_sem); + if (ret < 0) { + ret = 0; + goto next; + } + + ret = btrfs_zone_finish(block_group); + if (ret < 0) { + btrfs_dec_block_group_ro(block_group); + if (ret == -EAGAIN) + ret = 0; + goto next; + } + + /* + * Want to do this before we do anything else so we can recover + * properly if we fail to join the transaction. + */ + trans = btrfs_start_trans_remove_block_group(fs_info, + block_group->start); + if (IS_ERR(trans)) { + btrfs_dec_block_group_ro(block_group); + ret = PTR_ERR(trans); + goto next; + } + + /* + * We could have pending pinned extents for this block group, + * just delete them, we don't care about them anymore. + */ + if (!clean_pinned_extents(trans, block_group)) { + btrfs_dec_block_group_ro(block_group); + goto end_trans; + } + + /* + * At this point, the block_group is read only and should fail + * new allocations. However, btrfs_finish_extent_commit() can + * cause this block_group to be placed back on the discard + * lists because now the block_group isn't fully discarded. + * Bail here and try again later after discarding everything. + */ + spin_lock(&fs_info->discard_ctl.lock); + if (!list_empty(&block_group->discard_list)) { + spin_unlock(&fs_info->discard_ctl.lock); + btrfs_dec_block_group_ro(block_group); + btrfs_discard_queue_work(&fs_info->discard_ctl, + block_group); + goto end_trans; + } + spin_unlock(&fs_info->discard_ctl.lock); + + /* Reset pinned so btrfs_put_block_group doesn't complain */ + spin_lock(&space_info->lock); + spin_lock(&block_group->lock); + + btrfs_space_info_update_bytes_pinned(fs_info, space_info, + -block_group->pinned); + space_info->bytes_readonly += block_group->pinned; + block_group->pinned = 0; + + spin_unlock(&block_group->lock); + spin_unlock(&space_info->lock); + + /* + * The normal path here is an unused block group is passed here, + * then trimming is handled in the transaction commit path. + * Async discard interposes before this to do the trimming + * before coming down the unused block group path as trimming + * will no longer be done later in the transaction commit path. + */ + if (!async_trim_enabled && btrfs_test_opt(fs_info, DISCARD_ASYNC)) + goto flip_async; + + /* + * DISCARD can flip during remount. On zoned filesystems, we + * need to reset sequential-required zones. + */ + trimming = btrfs_test_opt(fs_info, DISCARD_SYNC) || + btrfs_is_zoned(fs_info); + + /* Implicit trim during transaction commit. */ + if (trimming) + btrfs_freeze_block_group(block_group); + + /* + * Btrfs_remove_chunk will abort the transaction if things go + * horribly wrong. + */ + ret = btrfs_remove_chunk(trans, block_group->start); + + if (ret) { + if (trimming) + btrfs_unfreeze_block_group(block_group); + goto end_trans; + } + + /* + * If we're not mounted with -odiscard, we can just forget + * about this block group. Otherwise we'll need to wait + * until transaction commit to do the actual discard. + */ + if (trimming) { + spin_lock(&fs_info->unused_bgs_lock); + /* + * A concurrent scrub might have added us to the list + * fs_info->unused_bgs, so use a list_move operation + * to add the block group to the deleted_bgs list. + */ + list_move(&block_group->bg_list, + &trans->transaction->deleted_bgs); + spin_unlock(&fs_info->unused_bgs_lock); + btrfs_get_block_group(block_group); + } +end_trans: + btrfs_end_transaction(trans); +next: + btrfs_put_block_group(block_group); + spin_lock(&fs_info->unused_bgs_lock); + } + spin_unlock(&fs_info->unused_bgs_lock); + mutex_unlock(&fs_info->reclaim_bgs_lock); + return; + +flip_async: + btrfs_end_transaction(trans); + mutex_unlock(&fs_info->reclaim_bgs_lock); + btrfs_put_block_group(block_group); + btrfs_discard_punt_unused_bgs_list(fs_info); +} + +void btrfs_mark_bg_unused(struct btrfs_block_group *bg) +{ + struct btrfs_fs_info *fs_info = bg->fs_info; + + spin_lock(&fs_info->unused_bgs_lock); + if (list_empty(&bg->bg_list)) { + btrfs_get_block_group(bg); + trace_btrfs_add_unused_block_group(bg); + list_add_tail(&bg->bg_list, &fs_info->unused_bgs); + } else if (!test_bit(BLOCK_GROUP_FLAG_NEW, &bg->runtime_flags)) { + /* Pull out the block group from the reclaim_bgs list. */ + trace_btrfs_add_unused_block_group(bg); + list_move_tail(&bg->bg_list, &fs_info->unused_bgs); + } + spin_unlock(&fs_info->unused_bgs_lock); +} + +/* + * We want block groups with a low number of used bytes to be in the beginning + * of the list, so they will get reclaimed first. + */ +static int reclaim_bgs_cmp(void *unused, const struct list_head *a, + const struct list_head *b) +{ + const struct btrfs_block_group *bg1, *bg2; + + bg1 = list_entry(a, struct btrfs_block_group, bg_list); + bg2 = list_entry(b, struct btrfs_block_group, bg_list); + + return bg1->used > bg2->used; +} + +static inline bool btrfs_should_reclaim(struct btrfs_fs_info *fs_info) +{ + if (btrfs_is_zoned(fs_info)) + return btrfs_zoned_should_reclaim(fs_info); + return true; +} + +void btrfs_reclaim_bgs_work(struct work_struct *work) +{ + struct btrfs_fs_info *fs_info = + container_of(work, struct btrfs_fs_info, reclaim_bgs_work); + struct btrfs_block_group *bg; + struct btrfs_space_info *space_info; + + if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags)) + return; + + if (btrfs_fs_closing(fs_info)) + return; + + if (!btrfs_should_reclaim(fs_info)) + return; + + sb_start_write(fs_info->sb); + + if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE)) { + sb_end_write(fs_info->sb); + return; + } + + /* + * Long running balances can keep us blocked here for eternity, so + * simply skip reclaim if we're unable to get the mutex. + */ + if (!mutex_trylock(&fs_info->reclaim_bgs_lock)) { + btrfs_exclop_finish(fs_info); + sb_end_write(fs_info->sb); + return; + } + + spin_lock(&fs_info->unused_bgs_lock); + /* + * Sort happens under lock because we can't simply splice it and sort. + * The block groups might still be in use and reachable via bg_list, + * and their presence in the reclaim_bgs list must be preserved. + */ + list_sort(NULL, &fs_info->reclaim_bgs, reclaim_bgs_cmp); + while (!list_empty(&fs_info->reclaim_bgs)) { + u64 zone_unusable; + int ret = 0; + + bg = list_first_entry(&fs_info->reclaim_bgs, + struct btrfs_block_group, + bg_list); + list_del_init(&bg->bg_list); + + space_info = bg->space_info; + spin_unlock(&fs_info->unused_bgs_lock); + + /* Don't race with allocators so take the groups_sem */ + down_write(&space_info->groups_sem); + + spin_lock(&bg->lock); + if (bg->reserved || bg->pinned || bg->ro) { + /* + * We want to bail if we made new allocations or have + * outstanding allocations in this block group. We do + * the ro check in case balance is currently acting on + * this block group. + */ + spin_unlock(&bg->lock); + up_write(&space_info->groups_sem); + goto next; + } + spin_unlock(&bg->lock); + + /* + * Get out fast, in case we're read-only or unmounting the + * filesystem. It is OK to drop block groups from the list even + * for the read-only case. As we did sb_start_write(), + * "mount -o remount,ro" won't happen and read-only filesystem + * means it is forced read-only due to a fatal error. So, it + * never gets back to read-write to let us reclaim again. + */ + if (btrfs_need_cleaner_sleep(fs_info)) { + up_write(&space_info->groups_sem); + goto next; + } + + /* + * Cache the zone_unusable value before turning the block group + * to read only. As soon as the blog group is read only it's + * zone_unusable value gets moved to the block group's read-only + * bytes and isn't available for calculations anymore. + */ + zone_unusable = bg->zone_unusable; + ret = inc_block_group_ro(bg, 0); + up_write(&space_info->groups_sem); + if (ret < 0) + goto next; + + btrfs_info(fs_info, + "reclaiming chunk %llu with %llu%% used %llu%% unusable", + bg->start, + div64_u64(bg->used * 100, bg->length), + div64_u64(zone_unusable * 100, bg->length)); + trace_btrfs_reclaim_block_group(bg); + ret = btrfs_relocate_chunk(fs_info, bg->start); + if (ret) { + btrfs_dec_block_group_ro(bg); + btrfs_err(fs_info, "error relocating chunk %llu", + bg->start); + } + +next: + if (ret) + btrfs_mark_bg_to_reclaim(bg); + btrfs_put_block_group(bg); + + mutex_unlock(&fs_info->reclaim_bgs_lock); + /* + * Reclaiming all the block groups in the list can take really + * long. Prioritize cleaning up unused block groups. + */ + btrfs_delete_unused_bgs(fs_info); + /* + * If we are interrupted by a balance, we can just bail out. The + * cleaner thread restart again if necessary. + */ + if (!mutex_trylock(&fs_info->reclaim_bgs_lock)) + goto end; + spin_lock(&fs_info->unused_bgs_lock); + } + spin_unlock(&fs_info->unused_bgs_lock); + mutex_unlock(&fs_info->reclaim_bgs_lock); +end: + btrfs_exclop_finish(fs_info); + sb_end_write(fs_info->sb); +} + +void btrfs_reclaim_bgs(struct btrfs_fs_info *fs_info) +{ + spin_lock(&fs_info->unused_bgs_lock); + if (!list_empty(&fs_info->reclaim_bgs)) + queue_work(system_unbound_wq, &fs_info->reclaim_bgs_work); + spin_unlock(&fs_info->unused_bgs_lock); +} + +void btrfs_mark_bg_to_reclaim(struct btrfs_block_group *bg) +{ + struct btrfs_fs_info *fs_info = bg->fs_info; + + spin_lock(&fs_info->unused_bgs_lock); + if (list_empty(&bg->bg_list)) { + btrfs_get_block_group(bg); + trace_btrfs_add_reclaim_block_group(bg); + list_add_tail(&bg->bg_list, &fs_info->reclaim_bgs); + } + spin_unlock(&fs_info->unused_bgs_lock); +} + +static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key, + struct btrfs_path *path) +{ + struct extent_map_tree *em_tree; + struct extent_map *em; + struct btrfs_block_group_item bg; + struct extent_buffer *leaf; + int slot; + u64 flags; + int ret = 0; + + slot = path->slots[0]; + leaf = path->nodes[0]; + + em_tree = &fs_info->mapping_tree; + read_lock(&em_tree->lock); + em = lookup_extent_mapping(em_tree, key->objectid, key->offset); + read_unlock(&em_tree->lock); + if (!em) { + btrfs_err(fs_info, + "logical %llu len %llu found bg but no related chunk", + key->objectid, key->offset); + return -ENOENT; + } + + if (em->start != key->objectid || em->len != key->offset) { + btrfs_err(fs_info, + "block group %llu len %llu mismatch with chunk %llu len %llu", + key->objectid, key->offset, em->start, em->len); + ret = -EUCLEAN; + goto out_free_em; + } + + read_extent_buffer(leaf, &bg, btrfs_item_ptr_offset(leaf, slot), + sizeof(bg)); + flags = btrfs_stack_block_group_flags(&bg) & + BTRFS_BLOCK_GROUP_TYPE_MASK; + + if (flags != (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) { + btrfs_err(fs_info, +"block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx", + key->objectid, key->offset, flags, + (BTRFS_BLOCK_GROUP_TYPE_MASK & em->map_lookup->type)); + ret = -EUCLEAN; + } + +out_free_em: + free_extent_map(em); + return ret; +} + +static int find_first_block_group(struct btrfs_fs_info *fs_info, + struct btrfs_path *path, + struct btrfs_key *key) +{ + struct btrfs_root *root = btrfs_block_group_root(fs_info); + int ret; + struct btrfs_key found_key; + + btrfs_for_each_slot(root, key, &found_key, path, ret) { + if (found_key.objectid >= key->objectid && + found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) { + return read_bg_from_eb(fs_info, &found_key, path); + } + } + return ret; +} + +static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags) +{ + u64 extra_flags = chunk_to_extended(flags) & + BTRFS_EXTENDED_PROFILE_MASK; + + write_seqlock(&fs_info->profiles_lock); + if (flags & BTRFS_BLOCK_GROUP_DATA) + fs_info->avail_data_alloc_bits |= extra_flags; + if (flags & BTRFS_BLOCK_GROUP_METADATA) + fs_info->avail_metadata_alloc_bits |= extra_flags; + if (flags & BTRFS_BLOCK_GROUP_SYSTEM) + fs_info->avail_system_alloc_bits |= extra_flags; + write_sequnlock(&fs_info->profiles_lock); +} + +/** + * Map a physical disk address to a list of logical addresses + * + * @fs_info: the filesystem + * @chunk_start: logical address of block group + * @bdev: physical device to resolve, can be NULL to indicate any device + * @physical: physical address to map to logical addresses + * @logical: return array of logical addresses which map to @physical + * @naddrs: length of @logical + * @stripe_len: size of IO stripe for the given block group + * + * Maps a particular @physical disk address to a list of @logical addresses. + * Used primarily to exclude those portions of a block group that contain super + * block copies. + */ +int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start, + struct block_device *bdev, u64 physical, u64 **logical, + int *naddrs, int *stripe_len) +{ + struct extent_map *em; + struct map_lookup *map; + u64 *buf; + u64 bytenr; + u64 data_stripe_length; + u64 io_stripe_size; + int i, nr = 0; + int ret = 0; + + em = btrfs_get_chunk_map(fs_info, chunk_start, 1); + if (IS_ERR(em)) + return -EIO; + + map = em->map_lookup; + data_stripe_length = em->orig_block_len; + io_stripe_size = map->stripe_len; + chunk_start = em->start; + + /* For RAID5/6 adjust to a full IO stripe length */ + if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) + io_stripe_size = map->stripe_len * nr_data_stripes(map); + + buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS); + if (!buf) { + ret = -ENOMEM; + goto out; + } + + for (i = 0; i < map->num_stripes; i++) { + bool already_inserted = false; + u64 stripe_nr; + u64 offset; + int j; + + if (!in_range(physical, map->stripes[i].physical, + data_stripe_length)) + continue; + + if (bdev && map->stripes[i].dev->bdev != bdev) + continue; + + stripe_nr = physical - map->stripes[i].physical; + stripe_nr = div64_u64_rem(stripe_nr, map->stripe_len, &offset); + + if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | + BTRFS_BLOCK_GROUP_RAID10)) { + stripe_nr = stripe_nr * map->num_stripes + i; + stripe_nr = div_u64(stripe_nr, map->sub_stripes); + } + /* + * The remaining case would be for RAID56, multiply by + * nr_data_stripes(). Alternatively, just use rmap_len below + * instead of map->stripe_len + */ + + bytenr = chunk_start + stripe_nr * io_stripe_size + offset; + + /* Ensure we don't add duplicate addresses */ + for (j = 0; j < nr; j++) { + if (buf[j] == bytenr) { + already_inserted = true; + break; + } + } + + if (!already_inserted) + buf[nr++] = bytenr; + } + + *logical = buf; + *naddrs = nr; + *stripe_len = io_stripe_size; +out: + free_extent_map(em); + return ret; +} + +static int exclude_super_stripes(struct btrfs_block_group *cache) +{ + struct btrfs_fs_info *fs_info = cache->fs_info; + const bool zoned = btrfs_is_zoned(fs_info); + u64 bytenr; + u64 *logical; + int stripe_len; + int i, nr, ret; + + if (cache->start < BTRFS_SUPER_INFO_OFFSET) { + stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->start; + cache->bytes_super += stripe_len; + ret = btrfs_add_excluded_extent(fs_info, cache->start, + stripe_len); + if (ret) + return ret; + } + + for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) { + bytenr = btrfs_sb_offset(i); + ret = btrfs_rmap_block(fs_info, cache->start, NULL, + bytenr, &logical, &nr, &stripe_len); + if (ret) + return ret; + + /* Shouldn't have super stripes in sequential zones */ + if (zoned && nr) { + kfree(logical); + btrfs_err(fs_info, + "zoned: block group %llu must not contain super block", + cache->start); + return -EUCLEAN; + } + + while (nr--) { + u64 len = min_t(u64, stripe_len, + cache->start + cache->length - logical[nr]); + + cache->bytes_super += len; + ret = btrfs_add_excluded_extent(fs_info, logical[nr], + len); + if (ret) { + kfree(logical); + return ret; + } + } + + kfree(logical); + } + return 0; +} + +static struct btrfs_block_group *btrfs_create_block_group_cache( + struct btrfs_fs_info *fs_info, u64 start) +{ + struct btrfs_block_group *cache; + + cache = kzalloc(sizeof(*cache), GFP_NOFS); + if (!cache) + return NULL; + + cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl), + GFP_NOFS); + if (!cache->free_space_ctl) { + kfree(cache); + return NULL; + } + + cache->start = start; + + cache->fs_info = fs_info; + cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start); + + cache->discard_index = BTRFS_DISCARD_INDEX_UNUSED; + + refcount_set(&cache->refs, 1); + spin_lock_init(&cache->lock); + init_rwsem(&cache->data_rwsem); + INIT_LIST_HEAD(&cache->list); + INIT_LIST_HEAD(&cache->cluster_list); + INIT_LIST_HEAD(&cache->bg_list); + INIT_LIST_HEAD(&cache->ro_list); + INIT_LIST_HEAD(&cache->discard_list); + INIT_LIST_HEAD(&cache->dirty_list); + INIT_LIST_HEAD(&cache->io_list); + INIT_LIST_HEAD(&cache->active_bg_list); + btrfs_init_free_space_ctl(cache, cache->free_space_ctl); + atomic_set(&cache->frozen, 0); + mutex_init(&cache->free_space_lock); + cache->full_stripe_locks_root.root = RB_ROOT; + mutex_init(&cache->full_stripe_locks_root.lock); + + return cache; +} + +/* + * Iterate all chunks and verify that each of them has the corresponding block + * group + */ +static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info) +{ + struct extent_map_tree *map_tree = &fs_info->mapping_tree; + struct extent_map *em; + struct btrfs_block_group *bg; + u64 start = 0; + int ret = 0; + + while (1) { + read_lock(&map_tree->lock); + /* + * lookup_extent_mapping will return the first extent map + * intersecting the range, so setting @len to 1 is enough to + * get the first chunk. + */ + em = lookup_extent_mapping(map_tree, start, 1); + read_unlock(&map_tree->lock); + if (!em) + break; + + bg = btrfs_lookup_block_group(fs_info, em->start); + if (!bg) { + btrfs_err(fs_info, + "chunk start=%llu len=%llu doesn't have corresponding block group", + em->start, em->len); + ret = -EUCLEAN; + free_extent_map(em); + break; + } + if (bg->start != em->start || bg->length != em->len || + (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) != + (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) { + btrfs_err(fs_info, +"chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx", + em->start, em->len, + em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK, + bg->start, bg->length, + bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK); + ret = -EUCLEAN; + free_extent_map(em); + btrfs_put_block_group(bg); + break; + } + start = em->start + em->len; + free_extent_map(em); + btrfs_put_block_group(bg); + } + return ret; +} + +static int read_one_block_group(struct btrfs_fs_info *info, + struct btrfs_block_group_item *bgi, + const struct btrfs_key *key, + int need_clear) +{ + struct btrfs_block_group *cache; + const bool mixed = btrfs_fs_incompat(info, MIXED_GROUPS); + int ret; + + ASSERT(key->type == BTRFS_BLOCK_GROUP_ITEM_KEY); + + cache = btrfs_create_block_group_cache(info, key->objectid); + if (!cache) + return -ENOMEM; + + cache->length = key->offset; + cache->used = btrfs_stack_block_group_used(bgi); + cache->flags = btrfs_stack_block_group_flags(bgi); + cache->global_root_id = btrfs_stack_block_group_chunk_objectid(bgi); + + set_free_space_tree_thresholds(cache); + + if (need_clear) { + /* + * When we mount with old space cache, we need to + * set BTRFS_DC_CLEAR and set dirty flag. + * + * a) Setting 'BTRFS_DC_CLEAR' makes sure that we + * truncate the old free space cache inode and + * setup a new one. + * b) Setting 'dirty flag' makes sure that we flush + * the new space cache info onto disk. + */ + if (btrfs_test_opt(info, SPACE_CACHE)) + cache->disk_cache_state = BTRFS_DC_CLEAR; + } + if (!mixed && ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) && + (cache->flags & BTRFS_BLOCK_GROUP_DATA))) { + btrfs_err(info, +"bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups", + cache->start); + ret = -EINVAL; + goto error; + } + + ret = btrfs_load_block_group_zone_info(cache, false); + if (ret) { + btrfs_err(info, "zoned: failed to load zone info of bg %llu", + cache->start); + goto error; + } + + /* + * We need to exclude the super stripes now so that the space info has + * super bytes accounted for, otherwise we'll think we have more space + * than we actually do. + */ + ret = exclude_super_stripes(cache); + if (ret) { + /* We may have excluded something, so call this just in case. */ + btrfs_free_excluded_extents(cache); + goto error; + } + + /* + * For zoned filesystem, space after the allocation offset is the only + * free space for a block group. So, we don't need any caching work. + * btrfs_calc_zone_unusable() will set the amount of free space and + * zone_unusable space. + * + * For regular filesystem, check for two cases, either we are full, and + * therefore don't need to bother with the caching work since we won't + * find any space, or we are empty, and we can just add all the space + * in and be done with it. This saves us _a_lot_ of time, particularly + * in the full case. + */ + if (btrfs_is_zoned(info)) { + btrfs_calc_zone_unusable(cache); + /* Should not have any excluded extents. Just in case, though. */ + btrfs_free_excluded_extents(cache); + } else if (cache->length == cache->used) { + cache->cached = BTRFS_CACHE_FINISHED; + btrfs_free_excluded_extents(cache); + } else if (cache->used == 0) { + cache->cached = BTRFS_CACHE_FINISHED; + ret = add_new_free_space(cache, cache->start, + cache->start + cache->length, NULL); + btrfs_free_excluded_extents(cache); + if (ret) + goto error; + } + + ret = btrfs_add_block_group_cache(info, cache); + if (ret) { + btrfs_remove_free_space_cache(cache); + goto error; + } + trace_btrfs_add_block_group(info, cache, 0); + btrfs_add_bg_to_space_info(info, cache); + + set_avail_alloc_bits(info, cache->flags); + if (btrfs_chunk_writeable(info, cache->start)) { + if (cache->used == 0) { + ASSERT(list_empty(&cache->bg_list)); + if (btrfs_test_opt(info, DISCARD_ASYNC)) + btrfs_discard_queue_work(&info->discard_ctl, cache); + else + btrfs_mark_bg_unused(cache); + } + } else { + inc_block_group_ro(cache, 1); + } + + return 0; +error: + btrfs_put_block_group(cache); + return ret; +} + +static int fill_dummy_bgs(struct btrfs_fs_info *fs_info) +{ + struct extent_map_tree *em_tree = &fs_info->mapping_tree; + struct rb_node *node; + int ret = 0; + + for (node = rb_first_cached(&em_tree->map); node; node = rb_next(node)) { + struct extent_map *em; + struct map_lookup *map; + struct btrfs_block_group *bg; + + em = rb_entry(node, struct extent_map, rb_node); + map = em->map_lookup; + bg = btrfs_create_block_group_cache(fs_info, em->start); + if (!bg) { + ret = -ENOMEM; + break; + } + + /* Fill dummy cache as FULL */ + bg->length = em->len; + bg->flags = map->type; + bg->cached = BTRFS_CACHE_FINISHED; + bg->used = em->len; + bg->flags = map->type; + ret = btrfs_add_block_group_cache(fs_info, bg); + /* + * We may have some valid block group cache added already, in + * that case we skip to the next one. + */ + if (ret == -EEXIST) { + ret = 0; + btrfs_put_block_group(bg); + continue; + } + + if (ret) { + btrfs_remove_free_space_cache(bg); + btrfs_put_block_group(bg); + break; + } + + btrfs_add_bg_to_space_info(fs_info, bg); + + set_avail_alloc_bits(fs_info, bg->flags); + } + if (!ret) + btrfs_init_global_block_rsv(fs_info); + return ret; +} + +int btrfs_read_block_groups(struct btrfs_fs_info *info) +{ + struct btrfs_root *root = btrfs_block_group_root(info); + struct btrfs_path *path; + int ret; + struct btrfs_block_group *cache; + struct btrfs_space_info *space_info; + struct btrfs_key key; + int need_clear = 0; + u64 cache_gen; + + /* + * Either no extent root (with ibadroots rescue option) or we have + * unsupported RO options. The fs can never be mounted read-write, so no + * need to waste time searching block group items. + * + * This also allows new extent tree related changes to be RO compat, + * no need for a full incompat flag. + */ + if (!root || (btrfs_super_compat_ro_flags(info->super_copy) & + ~BTRFS_FEATURE_COMPAT_RO_SUPP)) + return fill_dummy_bgs(info); + + key.objectid = 0; + key.offset = 0; + key.type = BTRFS_BLOCK_GROUP_ITEM_KEY; + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + cache_gen = btrfs_super_cache_generation(info->super_copy); + if (btrfs_test_opt(info, SPACE_CACHE) && + btrfs_super_generation(info->super_copy) != cache_gen) + need_clear = 1; + if (btrfs_test_opt(info, CLEAR_CACHE)) + need_clear = 1; + + while (1) { + struct btrfs_block_group_item bgi; + struct extent_buffer *leaf; + int slot; + + ret = find_first_block_group(info, path, &key); + if (ret > 0) + break; + if (ret != 0) + goto error; + + leaf = path->nodes[0]; + slot = path->slots[0]; + + read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot), + sizeof(bgi)); + + btrfs_item_key_to_cpu(leaf, &key, slot); + btrfs_release_path(path); + ret = read_one_block_group(info, &bgi, &key, need_clear); + if (ret < 0) + goto error; + key.objectid += key.offset; + key.offset = 0; + } + btrfs_release_path(path); + + list_for_each_entry(space_info, &info->space_info, list) { + int i; + + for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) { + if (list_empty(&space_info->block_groups[i])) + continue; + cache = list_first_entry(&space_info->block_groups[i], + struct btrfs_block_group, + list); + btrfs_sysfs_add_block_group_type(cache); + } + + if (!(btrfs_get_alloc_profile(info, space_info->flags) & + (BTRFS_BLOCK_GROUP_RAID10 | + BTRFS_BLOCK_GROUP_RAID1_MASK | + BTRFS_BLOCK_GROUP_RAID56_MASK | + BTRFS_BLOCK_GROUP_DUP))) + continue; + /* + * Avoid allocating from un-mirrored block group if there are + * mirrored block groups. + */ + list_for_each_entry(cache, + &space_info->block_groups[BTRFS_RAID_RAID0], + list) + inc_block_group_ro(cache, 1); + list_for_each_entry(cache, + &space_info->block_groups[BTRFS_RAID_SINGLE], + list) + inc_block_group_ro(cache, 1); + } + + btrfs_init_global_block_rsv(info); + ret = check_chunk_block_group_mappings(info); +error: + btrfs_free_path(path); + /* + * We've hit some error while reading the extent tree, and have + * rescue=ibadroots mount option. + * Try to fill the tree using dummy block groups so that the user can + * continue to mount and grab their data. + */ + if (ret && btrfs_test_opt(info, IGNOREBADROOTS)) + ret = fill_dummy_bgs(info); + return ret; +} + +/* + * This function, insert_block_group_item(), belongs to the phase 2 of chunk + * allocation. + * + * See the comment at btrfs_chunk_alloc() for details about the chunk allocation + * phases. + */ +static int insert_block_group_item(struct btrfs_trans_handle *trans, + struct btrfs_block_group *block_group) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_block_group_item bgi; + struct btrfs_root *root = btrfs_block_group_root(fs_info); + struct btrfs_key key; + + spin_lock(&block_group->lock); + btrfs_set_stack_block_group_used(&bgi, block_group->used); + btrfs_set_stack_block_group_chunk_objectid(&bgi, + block_group->global_root_id); + btrfs_set_stack_block_group_flags(&bgi, block_group->flags); + key.objectid = block_group->start; + key.type = BTRFS_BLOCK_GROUP_ITEM_KEY; + key.offset = block_group->length; + spin_unlock(&block_group->lock); + + return btrfs_insert_item(trans, root, &key, &bgi, sizeof(bgi)); +} + +static int insert_dev_extent(struct btrfs_trans_handle *trans, + struct btrfs_device *device, u64 chunk_offset, + u64 start, u64 num_bytes) +{ + struct btrfs_fs_info *fs_info = device->fs_info; + struct btrfs_root *root = fs_info->dev_root; + struct btrfs_path *path; + struct btrfs_dev_extent *extent; + struct extent_buffer *leaf; + struct btrfs_key key; + int ret; + + WARN_ON(!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state)); + WARN_ON(test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)); + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + key.objectid = device->devid; + key.type = BTRFS_DEV_EXTENT_KEY; + key.offset = start; + ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*extent)); + if (ret) + goto out; + + leaf = path->nodes[0]; + extent = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_extent); + btrfs_set_dev_extent_chunk_tree(leaf, extent, BTRFS_CHUNK_TREE_OBJECTID); + btrfs_set_dev_extent_chunk_objectid(leaf, extent, + BTRFS_FIRST_CHUNK_TREE_OBJECTID); + btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset); + + btrfs_set_dev_extent_length(leaf, extent, num_bytes); + btrfs_mark_buffer_dirty(leaf); +out: + btrfs_free_path(path); + return ret; +} + +/* + * This function belongs to phase 2. + * + * See the comment at btrfs_chunk_alloc() for details about the chunk allocation + * phases. + */ +static int insert_dev_extents(struct btrfs_trans_handle *trans, + u64 chunk_offset, u64 chunk_size) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_device *device; + struct extent_map *em; + struct map_lookup *map; + u64 dev_offset; + u64 stripe_size; + int i; + int ret = 0; + + em = btrfs_get_chunk_map(fs_info, chunk_offset, chunk_size); + if (IS_ERR(em)) + return PTR_ERR(em); + + map = em->map_lookup; + stripe_size = em->orig_block_len; + + /* + * Take the device list mutex to prevent races with the final phase of + * a device replace operation that replaces the device object associated + * with the map's stripes, because the device object's id can change + * at any time during that final phase of the device replace operation + * (dev-replace.c:btrfs_dev_replace_finishing()), so we could grab the + * replaced device and then see it with an ID of BTRFS_DEV_REPLACE_DEVID, + * resulting in persisting a device extent item with such ID. + */ + mutex_lock(&fs_info->fs_devices->device_list_mutex); + for (i = 0; i < map->num_stripes; i++) { + device = map->stripes[i].dev; + dev_offset = map->stripes[i].physical; + + ret = insert_dev_extent(trans, device, chunk_offset, dev_offset, + stripe_size); + if (ret) + break; + } + mutex_unlock(&fs_info->fs_devices->device_list_mutex); + + free_extent_map(em); + return ret; +} + +/* + * This function, btrfs_create_pending_block_groups(), belongs to the phase 2 of + * chunk allocation. + * + * See the comment at btrfs_chunk_alloc() for details about the chunk allocation + * phases. + */ +void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_block_group *block_group; + int ret = 0; + + while (!list_empty(&trans->new_bgs)) { + int index; + + block_group = list_first_entry(&trans->new_bgs, + struct btrfs_block_group, + bg_list); + if (ret) + goto next; + + index = btrfs_bg_flags_to_raid_index(block_group->flags); + + ret = insert_block_group_item(trans, block_group); + if (ret) + btrfs_abort_transaction(trans, ret); + if (!test_bit(BLOCK_GROUP_FLAG_CHUNK_ITEM_INSERTED, + &block_group->runtime_flags)) { + mutex_lock(&fs_info->chunk_mutex); + ret = btrfs_chunk_alloc_add_chunk_item(trans, block_group); + mutex_unlock(&fs_info->chunk_mutex); + if (ret) + btrfs_abort_transaction(trans, ret); + } + ret = insert_dev_extents(trans, block_group->start, + block_group->length); + if (ret) + btrfs_abort_transaction(trans, ret); + add_block_group_free_space(trans, block_group); + + /* + * If we restriped during balance, we may have added a new raid + * type, so now add the sysfs entries when it is safe to do so. + * We don't have to worry about locking here as it's handled in + * btrfs_sysfs_add_block_group_type. + */ + if (block_group->space_info->block_group_kobjs[index] == NULL) + btrfs_sysfs_add_block_group_type(block_group); + + /* Already aborted the transaction if it failed. */ +next: + btrfs_delayed_refs_rsv_release(fs_info, 1); + list_del_init(&block_group->bg_list); + clear_bit(BLOCK_GROUP_FLAG_NEW, &block_group->runtime_flags); + } + btrfs_trans_release_chunk_metadata(trans); +} + +/* + * For extent tree v2 we use the block_group_item->chunk_offset to point at our + * global root id. For v1 it's always set to BTRFS_FIRST_CHUNK_TREE_OBJECTID. + */ +static u64 calculate_global_root_id(struct btrfs_fs_info *fs_info, u64 offset) +{ + u64 div = SZ_1G; + u64 index; + + if (!btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) + return BTRFS_FIRST_CHUNK_TREE_OBJECTID; + + /* If we have a smaller fs index based on 128MiB. */ + if (btrfs_super_total_bytes(fs_info->super_copy) <= (SZ_1G * 10ULL)) + div = SZ_128M; + + offset = div64_u64(offset, div); + div64_u64_rem(offset, fs_info->nr_global_roots, &index); + return index; +} + +struct btrfs_block_group *btrfs_make_block_group(struct btrfs_trans_handle *trans, + u64 bytes_used, u64 type, + u64 chunk_offset, u64 size) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_block_group *cache; + int ret; + + btrfs_set_log_full_commit(trans); + + cache = btrfs_create_block_group_cache(fs_info, chunk_offset); + if (!cache) + return ERR_PTR(-ENOMEM); + + /* + * Mark it as new before adding it to the rbtree of block groups or any + * list, so that no other task finds it and calls btrfs_mark_bg_unused() + * before the new flag is set. + */ + set_bit(BLOCK_GROUP_FLAG_NEW, &cache->runtime_flags); + + cache->length = size; + set_free_space_tree_thresholds(cache); + cache->used = bytes_used; + cache->flags = type; + cache->cached = BTRFS_CACHE_FINISHED; + cache->global_root_id = calculate_global_root_id(fs_info, cache->start); + + if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) + set_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &cache->runtime_flags); + + ret = btrfs_load_block_group_zone_info(cache, true); + if (ret) { + btrfs_put_block_group(cache); + return ERR_PTR(ret); + } + + ret = exclude_super_stripes(cache); + if (ret) { + /* We may have excluded something, so call this just in case */ + btrfs_free_excluded_extents(cache); + btrfs_put_block_group(cache); + return ERR_PTR(ret); + } + + ret = add_new_free_space(cache, chunk_offset, chunk_offset + size, NULL); + btrfs_free_excluded_extents(cache); + if (ret) { + btrfs_put_block_group(cache); + return ERR_PTR(ret); + } + + /* + * Ensure the corresponding space_info object is created and + * assigned to our block group. We want our bg to be added to the rbtree + * with its ->space_info set. + */ + cache->space_info = btrfs_find_space_info(fs_info, cache->flags); + ASSERT(cache->space_info); + + ret = btrfs_add_block_group_cache(fs_info, cache); + if (ret) { + btrfs_remove_free_space_cache(cache); + btrfs_put_block_group(cache); + return ERR_PTR(ret); + } + + /* + * Now that our block group has its ->space_info set and is inserted in + * the rbtree, update the space info's counters. + */ + trace_btrfs_add_block_group(fs_info, cache, 1); + btrfs_add_bg_to_space_info(fs_info, cache); + btrfs_update_global_block_rsv(fs_info); + +#ifdef CONFIG_BTRFS_DEBUG + if (btrfs_should_fragment_free_space(cache)) { + u64 new_bytes_used = size - bytes_used; + + cache->space_info->bytes_used += new_bytes_used >> 1; + fragment_free_space(cache); + } +#endif + + list_add_tail(&cache->bg_list, &trans->new_bgs); + trans->delayed_ref_updates++; + btrfs_update_delayed_refs_rsv(trans); + + set_avail_alloc_bits(fs_info, type); + return cache; +} + +/* + * Mark one block group RO, can be called several times for the same block + * group. + * + * @cache: the destination block group + * @do_chunk_alloc: whether need to do chunk pre-allocation, this is to + * ensure we still have some free space after marking this + * block group RO. + */ +int btrfs_inc_block_group_ro(struct btrfs_block_group *cache, + bool do_chunk_alloc) +{ + struct btrfs_fs_info *fs_info = cache->fs_info; + struct btrfs_trans_handle *trans; + struct btrfs_root *root = btrfs_block_group_root(fs_info); + u64 alloc_flags; + int ret; + bool dirty_bg_running; + + /* + * This can only happen when we are doing read-only scrub on read-only + * mount. + * In that case we should not start a new transaction on read-only fs. + * Thus here we skip all chunk allocations. + */ + if (sb_rdonly(fs_info->sb)) { + mutex_lock(&fs_info->ro_block_group_mutex); + ret = inc_block_group_ro(cache, 0); + mutex_unlock(&fs_info->ro_block_group_mutex); + return ret; + } + + do { + trans = btrfs_join_transaction(root); + if (IS_ERR(trans)) + return PTR_ERR(trans); + + dirty_bg_running = false; + + /* + * We're not allowed to set block groups readonly after the dirty + * block group cache has started writing. If it already started, + * back off and let this transaction commit. + */ + mutex_lock(&fs_info->ro_block_group_mutex); + if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) { + u64 transid = trans->transid; + + mutex_unlock(&fs_info->ro_block_group_mutex); + btrfs_end_transaction(trans); + + ret = btrfs_wait_for_commit(fs_info, transid); + if (ret) + return ret; + dirty_bg_running = true; + } + } while (dirty_bg_running); + + if (do_chunk_alloc) { + /* + * If we are changing raid levels, try to allocate a + * corresponding block group with the new raid level. + */ + alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags); + if (alloc_flags != cache->flags) { + ret = btrfs_chunk_alloc(trans, alloc_flags, + CHUNK_ALLOC_FORCE); + /* + * ENOSPC is allowed here, we may have enough space + * already allocated at the new raid level to carry on + */ + if (ret == -ENOSPC) + ret = 0; + if (ret < 0) + goto out; + } + } + + ret = inc_block_group_ro(cache, 0); + if (!ret) + goto out; + if (ret == -ETXTBSY) + goto unlock_out; + + /* + * Skip chunk alloction if the bg is SYSTEM, this is to avoid system + * chunk allocation storm to exhaust the system chunk array. Otherwise + * we still want to try our best to mark the block group read-only. + */ + if (!do_chunk_alloc && ret == -ENOSPC && + (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM)) + goto unlock_out; + + alloc_flags = btrfs_get_alloc_profile(fs_info, cache->space_info->flags); + ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE); + if (ret < 0) + goto out; + /* + * We have allocated a new chunk. We also need to activate that chunk to + * grant metadata tickets for zoned filesystem. + */ + ret = btrfs_zoned_activate_one_bg(fs_info, cache->space_info, true); + if (ret < 0) + goto out; + + ret = inc_block_group_ro(cache, 0); + if (ret == -ETXTBSY) + goto unlock_out; +out: + if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) { + alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags); + mutex_lock(&fs_info->chunk_mutex); + check_system_chunk(trans, alloc_flags); + mutex_unlock(&fs_info->chunk_mutex); + } +unlock_out: + mutex_unlock(&fs_info->ro_block_group_mutex); + + btrfs_end_transaction(trans); + return ret; +} + +void btrfs_dec_block_group_ro(struct btrfs_block_group *cache) +{ + struct btrfs_space_info *sinfo = cache->space_info; + u64 num_bytes; + + BUG_ON(!cache->ro); + + spin_lock(&sinfo->lock); + spin_lock(&cache->lock); + if (!--cache->ro) { + if (btrfs_is_zoned(cache->fs_info)) { + /* Migrate zone_unusable bytes back */ + cache->zone_unusable = + (cache->alloc_offset - cache->used) + + (cache->length - cache->zone_capacity); + sinfo->bytes_zone_unusable += cache->zone_unusable; + sinfo->bytes_readonly -= cache->zone_unusable; + } + num_bytes = cache->length - cache->reserved - + cache->pinned - cache->bytes_super - + cache->zone_unusable - cache->used; + sinfo->bytes_readonly -= num_bytes; + list_del_init(&cache->ro_list); + } + spin_unlock(&cache->lock); + spin_unlock(&sinfo->lock); +} + +static int update_block_group_item(struct btrfs_trans_handle *trans, + struct btrfs_path *path, + struct btrfs_block_group *cache) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + int ret; + struct btrfs_root *root = btrfs_block_group_root(fs_info); + unsigned long bi; + struct extent_buffer *leaf; + struct btrfs_block_group_item bgi; + struct btrfs_key key; + + key.objectid = cache->start; + key.type = BTRFS_BLOCK_GROUP_ITEM_KEY; + key.offset = cache->length; + + ret = btrfs_search_slot(trans, root, &key, path, 0, 1); + if (ret) { + if (ret > 0) + ret = -ENOENT; + goto fail; + } + + leaf = path->nodes[0]; + bi = btrfs_item_ptr_offset(leaf, path->slots[0]); + btrfs_set_stack_block_group_used(&bgi, cache->used); + btrfs_set_stack_block_group_chunk_objectid(&bgi, + cache->global_root_id); + btrfs_set_stack_block_group_flags(&bgi, cache->flags); + write_extent_buffer(leaf, &bgi, bi, sizeof(bgi)); + btrfs_mark_buffer_dirty(leaf); +fail: + btrfs_release_path(path); + return ret; + +} + +static int cache_save_setup(struct btrfs_block_group *block_group, + struct btrfs_trans_handle *trans, + struct btrfs_path *path) +{ + struct btrfs_fs_info *fs_info = block_group->fs_info; + struct btrfs_root *root = fs_info->tree_root; + struct inode *inode = NULL; + struct extent_changeset *data_reserved = NULL; + u64 alloc_hint = 0; + int dcs = BTRFS_DC_ERROR; + u64 cache_size = 0; + int retries = 0; + int ret = 0; + + if (!btrfs_test_opt(fs_info, SPACE_CACHE)) + return 0; + + /* + * If this block group is smaller than 100 megs don't bother caching the + * block group. + */ + if (block_group->length < (100 * SZ_1M)) { + spin_lock(&block_group->lock); + block_group->disk_cache_state = BTRFS_DC_WRITTEN; + spin_unlock(&block_group->lock); + return 0; + } + + if (TRANS_ABORTED(trans)) + return 0; +again: + inode = lookup_free_space_inode(block_group, path); + if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) { + ret = PTR_ERR(inode); + btrfs_release_path(path); + goto out; + } + + if (IS_ERR(inode)) { + BUG_ON(retries); + retries++; + + if (block_group->ro) + goto out_free; + + ret = create_free_space_inode(trans, block_group, path); + if (ret) + goto out_free; + goto again; + } + + /* + * We want to set the generation to 0, that way if anything goes wrong + * from here on out we know not to trust this cache when we load up next + * time. + */ + BTRFS_I(inode)->generation = 0; + ret = btrfs_update_inode(trans, root, BTRFS_I(inode)); + if (ret) { + /* + * So theoretically we could recover from this, simply set the + * super cache generation to 0 so we know to invalidate the + * cache, but then we'd have to keep track of the block groups + * that fail this way so we know we _have_ to reset this cache + * before the next commit or risk reading stale cache. So to + * limit our exposure to horrible edge cases lets just abort the + * transaction, this only happens in really bad situations + * anyway. + */ + btrfs_abort_transaction(trans, ret); + goto out_put; + } + WARN_ON(ret); + + /* We've already setup this transaction, go ahead and exit */ + if (block_group->cache_generation == trans->transid && + i_size_read(inode)) { + dcs = BTRFS_DC_SETUP; + goto out_put; + } + + if (i_size_read(inode) > 0) { + ret = btrfs_check_trunc_cache_free_space(fs_info, + &fs_info->global_block_rsv); + if (ret) + goto out_put; + + ret = btrfs_truncate_free_space_cache(trans, NULL, inode); + if (ret) + goto out_put; + } + + spin_lock(&block_group->lock); + if (block_group->cached != BTRFS_CACHE_FINISHED || + !btrfs_test_opt(fs_info, SPACE_CACHE)) { + /* + * don't bother trying to write stuff out _if_ + * a) we're not cached, + * b) we're with nospace_cache mount option, + * c) we're with v2 space_cache (FREE_SPACE_TREE). + */ + dcs = BTRFS_DC_WRITTEN; + spin_unlock(&block_group->lock); + goto out_put; + } + spin_unlock(&block_group->lock); + + /* + * We hit an ENOSPC when setting up the cache in this transaction, just + * skip doing the setup, we've already cleared the cache so we're safe. + */ + if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) { + ret = -ENOSPC; + goto out_put; + } + + /* + * Try to preallocate enough space based on how big the block group is. + * Keep in mind this has to include any pinned space which could end up + * taking up quite a bit since it's not folded into the other space + * cache. + */ + cache_size = div_u64(block_group->length, SZ_256M); + if (!cache_size) + cache_size = 1; + + cache_size *= 16; + cache_size *= fs_info->sectorsize; + + ret = btrfs_check_data_free_space(BTRFS_I(inode), &data_reserved, 0, + cache_size, false); + if (ret) + goto out_put; + + ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, cache_size, + cache_size, cache_size, + &alloc_hint); + /* + * Our cache requires contiguous chunks so that we don't modify a bunch + * of metadata or split extents when writing the cache out, which means + * we can enospc if we are heavily fragmented in addition to just normal + * out of space conditions. So if we hit this just skip setting up any + * other block groups for this transaction, maybe we'll unpin enough + * space the next time around. + */ + if (!ret) + dcs = BTRFS_DC_SETUP; + else if (ret == -ENOSPC) + set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags); + +out_put: + iput(inode); +out_free: + btrfs_release_path(path); +out: + spin_lock(&block_group->lock); + if (!ret && dcs == BTRFS_DC_SETUP) + block_group->cache_generation = trans->transid; + block_group->disk_cache_state = dcs; + spin_unlock(&block_group->lock); + + extent_changeset_free(data_reserved); + return ret; +} + +int btrfs_setup_space_cache(struct btrfs_trans_handle *trans) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_block_group *cache, *tmp; + struct btrfs_transaction *cur_trans = trans->transaction; + struct btrfs_path *path; + + if (list_empty(&cur_trans->dirty_bgs) || + !btrfs_test_opt(fs_info, SPACE_CACHE)) + return 0; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + /* Could add new block groups, use _safe just in case */ + list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs, + dirty_list) { + if (cache->disk_cache_state == BTRFS_DC_CLEAR) + cache_save_setup(cache, trans, path); + } + + btrfs_free_path(path); + return 0; +} + +/* + * Transaction commit does final block group cache writeback during a critical + * section where nothing is allowed to change the FS. This is required in + * order for the cache to actually match the block group, but can introduce a + * lot of latency into the commit. + * + * So, btrfs_start_dirty_block_groups is here to kick off block group cache IO. + * There's a chance we'll have to redo some of it if the block group changes + * again during the commit, but it greatly reduces the commit latency by + * getting rid of the easy block groups while we're still allowing others to + * join the commit. + */ +int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_block_group *cache; + struct btrfs_transaction *cur_trans = trans->transaction; + int ret = 0; + int should_put; + struct btrfs_path *path = NULL; + LIST_HEAD(dirty); + struct list_head *io = &cur_trans->io_bgs; + int loops = 0; + + spin_lock(&cur_trans->dirty_bgs_lock); + if (list_empty(&cur_trans->dirty_bgs)) { + spin_unlock(&cur_trans->dirty_bgs_lock); + return 0; + } + list_splice_init(&cur_trans->dirty_bgs, &dirty); + spin_unlock(&cur_trans->dirty_bgs_lock); + +again: + /* Make sure all the block groups on our dirty list actually exist */ + btrfs_create_pending_block_groups(trans); + + if (!path) { + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + } + + /* + * cache_write_mutex is here only to save us from balance or automatic + * removal of empty block groups deleting this block group while we are + * writing out the cache + */ + mutex_lock(&trans->transaction->cache_write_mutex); + while (!list_empty(&dirty)) { + bool drop_reserve = true; + + cache = list_first_entry(&dirty, struct btrfs_block_group, + dirty_list); + /* + * This can happen if something re-dirties a block group that + * is already under IO. Just wait for it to finish and then do + * it all again + */ + if (!list_empty(&cache->io_list)) { + list_del_init(&cache->io_list); + btrfs_wait_cache_io(trans, cache, path); + btrfs_put_block_group(cache); + } + + + /* + * btrfs_wait_cache_io uses the cache->dirty_list to decide if + * it should update the cache_state. Don't delete until after + * we wait. + * + * Since we're not running in the commit critical section + * we need the dirty_bgs_lock to protect from update_block_group + */ + spin_lock(&cur_trans->dirty_bgs_lock); + list_del_init(&cache->dirty_list); + spin_unlock(&cur_trans->dirty_bgs_lock); + + should_put = 1; + + cache_save_setup(cache, trans, path); + + if (cache->disk_cache_state == BTRFS_DC_SETUP) { + cache->io_ctl.inode = NULL; + ret = btrfs_write_out_cache(trans, cache, path); + if (ret == 0 && cache->io_ctl.inode) { + should_put = 0; + + /* + * The cache_write_mutex is protecting the + * io_list, also refer to the definition of + * btrfs_transaction::io_bgs for more details + */ + list_add_tail(&cache->io_list, io); + } else { + /* + * If we failed to write the cache, the + * generation will be bad and life goes on + */ + ret = 0; + } + } + if (!ret) { + ret = update_block_group_item(trans, path, cache); + /* + * Our block group might still be attached to the list + * of new block groups in the transaction handle of some + * other task (struct btrfs_trans_handle->new_bgs). This + * means its block group item isn't yet in the extent + * tree. If this happens ignore the error, as we will + * try again later in the critical section of the + * transaction commit. + */ + if (ret == -ENOENT) { + ret = 0; + spin_lock(&cur_trans->dirty_bgs_lock); + if (list_empty(&cache->dirty_list)) { + list_add_tail(&cache->dirty_list, + &cur_trans->dirty_bgs); + btrfs_get_block_group(cache); + drop_reserve = false; + } + spin_unlock(&cur_trans->dirty_bgs_lock); + } else if (ret) { + btrfs_abort_transaction(trans, ret); + } + } + + /* If it's not on the io list, we need to put the block group */ + if (should_put) + btrfs_put_block_group(cache); + if (drop_reserve) + btrfs_delayed_refs_rsv_release(fs_info, 1); + /* + * Avoid blocking other tasks for too long. It might even save + * us from writing caches for block groups that are going to be + * removed. + */ + mutex_unlock(&trans->transaction->cache_write_mutex); + if (ret) + goto out; + mutex_lock(&trans->transaction->cache_write_mutex); + } + mutex_unlock(&trans->transaction->cache_write_mutex); + + /* + * Go through delayed refs for all the stuff we've just kicked off + * and then loop back (just once) + */ + if (!ret) + ret = btrfs_run_delayed_refs(trans, 0); + if (!ret && loops == 0) { + loops++; + spin_lock(&cur_trans->dirty_bgs_lock); + list_splice_init(&cur_trans->dirty_bgs, &dirty); + /* + * dirty_bgs_lock protects us from concurrent block group + * deletes too (not just cache_write_mutex). + */ + if (!list_empty(&dirty)) { + spin_unlock(&cur_trans->dirty_bgs_lock); + goto again; + } + spin_unlock(&cur_trans->dirty_bgs_lock); + } +out: + if (ret < 0) { + spin_lock(&cur_trans->dirty_bgs_lock); + list_splice_init(&dirty, &cur_trans->dirty_bgs); + spin_unlock(&cur_trans->dirty_bgs_lock); + btrfs_cleanup_dirty_bgs(cur_trans, fs_info); + } + + btrfs_free_path(path); + return ret; +} + +int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_block_group *cache; + struct btrfs_transaction *cur_trans = trans->transaction; + int ret = 0; + int should_put; + struct btrfs_path *path; + struct list_head *io = &cur_trans->io_bgs; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + /* + * Even though we are in the critical section of the transaction commit, + * we can still have concurrent tasks adding elements to this + * transaction's list of dirty block groups. These tasks correspond to + * endio free space workers started when writeback finishes for a + * space cache, which run inode.c:btrfs_finish_ordered_io(), and can + * allocate new block groups as a result of COWing nodes of the root + * tree when updating the free space inode. The writeback for the space + * caches is triggered by an earlier call to + * btrfs_start_dirty_block_groups() and iterations of the following + * loop. + * Also we want to do the cache_save_setup first and then run the + * delayed refs to make sure we have the best chance at doing this all + * in one shot. + */ + spin_lock(&cur_trans->dirty_bgs_lock); + while (!list_empty(&cur_trans->dirty_bgs)) { + cache = list_first_entry(&cur_trans->dirty_bgs, + struct btrfs_block_group, + dirty_list); + + /* + * This can happen if cache_save_setup re-dirties a block group + * that is already under IO. Just wait for it to finish and + * then do it all again + */ + if (!list_empty(&cache->io_list)) { + spin_unlock(&cur_trans->dirty_bgs_lock); + list_del_init(&cache->io_list); + btrfs_wait_cache_io(trans, cache, path); + btrfs_put_block_group(cache); + spin_lock(&cur_trans->dirty_bgs_lock); + } + + /* + * Don't remove from the dirty list until after we've waited on + * any pending IO + */ + list_del_init(&cache->dirty_list); + spin_unlock(&cur_trans->dirty_bgs_lock); + should_put = 1; + + cache_save_setup(cache, trans, path); + + if (!ret) + ret = btrfs_run_delayed_refs(trans, + (unsigned long) -1); + + if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) { + cache->io_ctl.inode = NULL; + ret = btrfs_write_out_cache(trans, cache, path); + if (ret == 0 && cache->io_ctl.inode) { + should_put = 0; + list_add_tail(&cache->io_list, io); + } else { + /* + * If we failed to write the cache, the + * generation will be bad and life goes on + */ + ret = 0; + } + } + if (!ret) { + ret = update_block_group_item(trans, path, cache); + /* + * One of the free space endio workers might have + * created a new block group while updating a free space + * cache's inode (at inode.c:btrfs_finish_ordered_io()) + * and hasn't released its transaction handle yet, in + * which case the new block group is still attached to + * its transaction handle and its creation has not + * finished yet (no block group item in the extent tree + * yet, etc). If this is the case, wait for all free + * space endio workers to finish and retry. This is a + * very rare case so no need for a more efficient and + * complex approach. + */ + if (ret == -ENOENT) { + wait_event(cur_trans->writer_wait, + atomic_read(&cur_trans->num_writers) == 1); + ret = update_block_group_item(trans, path, cache); + } + if (ret) + btrfs_abort_transaction(trans, ret); + } + + /* If its not on the io list, we need to put the block group */ + if (should_put) + btrfs_put_block_group(cache); + btrfs_delayed_refs_rsv_release(fs_info, 1); + spin_lock(&cur_trans->dirty_bgs_lock); + } + spin_unlock(&cur_trans->dirty_bgs_lock); + + /* + * Refer to the definition of io_bgs member for details why it's safe + * to use it without any locking + */ + while (!list_empty(io)) { + cache = list_first_entry(io, struct btrfs_block_group, + io_list); + list_del_init(&cache->io_list); + btrfs_wait_cache_io(trans, cache, path); + btrfs_put_block_group(cache); + } + + btrfs_free_path(path); + return ret; +} + +static inline bool should_reclaim_block_group(struct btrfs_block_group *bg, + u64 bytes_freed) +{ + const struct btrfs_space_info *space_info = bg->space_info; + const int reclaim_thresh = READ_ONCE(space_info->bg_reclaim_threshold); + const u64 new_val = bg->used; + const u64 old_val = new_val + bytes_freed; + u64 thresh; + + if (reclaim_thresh == 0) + return false; + + thresh = div_factor_fine(bg->length, reclaim_thresh); + + /* + * If we were below the threshold before don't reclaim, we are likely a + * brand new block group and we don't want to relocate new block groups. + */ + if (old_val < thresh) + return false; + if (new_val >= thresh) + return false; + return true; +} + +int btrfs_update_block_group(struct btrfs_trans_handle *trans, + u64 bytenr, u64 num_bytes, bool alloc) +{ + struct btrfs_fs_info *info = trans->fs_info; + struct btrfs_block_group *cache = NULL; + u64 total = num_bytes; + u64 old_val; + u64 byte_in_group; + int factor; + int ret = 0; + + /* Block accounting for super block */ + spin_lock(&info->delalloc_root_lock); + old_val = btrfs_super_bytes_used(info->super_copy); + if (alloc) + old_val += num_bytes; + else + old_val -= num_bytes; + btrfs_set_super_bytes_used(info->super_copy, old_val); + spin_unlock(&info->delalloc_root_lock); + + while (total) { + struct btrfs_space_info *space_info; + bool reclaim = false; + + cache = btrfs_lookup_block_group(info, bytenr); + if (!cache) { + ret = -ENOENT; + break; + } + space_info = cache->space_info; + factor = btrfs_bg_type_to_factor(cache->flags); + + /* + * If this block group has free space cache written out, we + * need to make sure to load it if we are removing space. This + * is because we need the unpinning stage to actually add the + * space back to the block group, otherwise we will leak space. + */ + if (!alloc && !btrfs_block_group_done(cache)) + btrfs_cache_block_group(cache, true); + + byte_in_group = bytenr - cache->start; + WARN_ON(byte_in_group > cache->length); + + spin_lock(&space_info->lock); + spin_lock(&cache->lock); + + if (btrfs_test_opt(info, SPACE_CACHE) && + cache->disk_cache_state < BTRFS_DC_CLEAR) + cache->disk_cache_state = BTRFS_DC_CLEAR; + + old_val = cache->used; + num_bytes = min(total, cache->length - byte_in_group); + if (alloc) { + old_val += num_bytes; + cache->used = old_val; + cache->reserved -= num_bytes; + space_info->bytes_reserved -= num_bytes; + space_info->bytes_used += num_bytes; + space_info->disk_used += num_bytes * factor; + spin_unlock(&cache->lock); + spin_unlock(&space_info->lock); + } else { + old_val -= num_bytes; + cache->used = old_val; + cache->pinned += num_bytes; + btrfs_space_info_update_bytes_pinned(info, space_info, + num_bytes); + space_info->bytes_used -= num_bytes; + space_info->disk_used -= num_bytes * factor; + + reclaim = should_reclaim_block_group(cache, num_bytes); + spin_unlock(&cache->lock); + spin_unlock(&space_info->lock); + + set_extent_dirty(&trans->transaction->pinned_extents, + bytenr, bytenr + num_bytes - 1, + GFP_NOFS | __GFP_NOFAIL); + } + + spin_lock(&trans->transaction->dirty_bgs_lock); + if (list_empty(&cache->dirty_list)) { + list_add_tail(&cache->dirty_list, + &trans->transaction->dirty_bgs); + trans->delayed_ref_updates++; + btrfs_get_block_group(cache); + } + spin_unlock(&trans->transaction->dirty_bgs_lock); + + /* + * No longer have used bytes in this block group, queue it for + * deletion. We do this after adding the block group to the + * dirty list to avoid races between cleaner kthread and space + * cache writeout. + */ + if (!alloc && old_val == 0) { + if (!btrfs_test_opt(info, DISCARD_ASYNC)) + btrfs_mark_bg_unused(cache); + } else if (!alloc && reclaim) { + btrfs_mark_bg_to_reclaim(cache); + } + + btrfs_put_block_group(cache); + total -= num_bytes; + bytenr += num_bytes; + } + + /* Modified block groups are accounted for in the delayed_refs_rsv. */ + btrfs_update_delayed_refs_rsv(trans); + return ret; +} + +/** + * btrfs_add_reserved_bytes - update the block_group and space info counters + * @cache: The cache we are manipulating + * @ram_bytes: The number of bytes of file content, and will be same to + * @num_bytes except for the compress path. + * @num_bytes: The number of bytes in question + * @delalloc: The blocks are allocated for the delalloc write + * + * This is called by the allocator when it reserves space. If this is a + * reservation and the block group has become read only we cannot make the + * reservation and return -EAGAIN, otherwise this function always succeeds. + */ +int btrfs_add_reserved_bytes(struct btrfs_block_group *cache, + u64 ram_bytes, u64 num_bytes, int delalloc) +{ + struct btrfs_space_info *space_info = cache->space_info; + int ret = 0; + + spin_lock(&space_info->lock); + spin_lock(&cache->lock); + if (cache->ro) { + ret = -EAGAIN; + } else { + cache->reserved += num_bytes; + space_info->bytes_reserved += num_bytes; + trace_btrfs_space_reservation(cache->fs_info, "space_info", + space_info->flags, num_bytes, 1); + btrfs_space_info_update_bytes_may_use(cache->fs_info, + space_info, -ram_bytes); + if (delalloc) + cache->delalloc_bytes += num_bytes; + + /* + * Compression can use less space than we reserved, so wake + * tickets if that happens + */ + if (num_bytes < ram_bytes) + btrfs_try_granting_tickets(cache->fs_info, space_info); + } + spin_unlock(&cache->lock); + spin_unlock(&space_info->lock); + return ret; +} + +/** + * btrfs_free_reserved_bytes - update the block_group and space info counters + * @cache: The cache we are manipulating + * @num_bytes: The number of bytes in question + * @delalloc: The blocks are allocated for the delalloc write + * + * This is called by somebody who is freeing space that was never actually used + * on disk. For example if you reserve some space for a new leaf in transaction + * A and before transaction A commits you free that leaf, you call this with + * reserve set to 0 in order to clear the reservation. + */ +void btrfs_free_reserved_bytes(struct btrfs_block_group *cache, + u64 num_bytes, int delalloc) +{ + struct btrfs_space_info *space_info = cache->space_info; + + spin_lock(&space_info->lock); + spin_lock(&cache->lock); + if (cache->ro) + space_info->bytes_readonly += num_bytes; + cache->reserved -= num_bytes; + space_info->bytes_reserved -= num_bytes; + space_info->max_extent_size = 0; + + if (delalloc) + cache->delalloc_bytes -= num_bytes; + spin_unlock(&cache->lock); + + btrfs_try_granting_tickets(cache->fs_info, space_info); + spin_unlock(&space_info->lock); +} + +static void force_metadata_allocation(struct btrfs_fs_info *info) +{ + struct list_head *head = &info->space_info; + struct btrfs_space_info *found; + + list_for_each_entry(found, head, list) { + if (found->flags & BTRFS_BLOCK_GROUP_METADATA) + found->force_alloc = CHUNK_ALLOC_FORCE; + } +} + +static int should_alloc_chunk(struct btrfs_fs_info *fs_info, + struct btrfs_space_info *sinfo, int force) +{ + u64 bytes_used = btrfs_space_info_used(sinfo, false); + u64 thresh; + + if (force == CHUNK_ALLOC_FORCE) + return 1; + + /* + * in limited mode, we want to have some free space up to + * about 1% of the FS size. + */ + if (force == CHUNK_ALLOC_LIMITED) { + thresh = btrfs_super_total_bytes(fs_info->super_copy); + thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1)); + + if (sinfo->total_bytes - bytes_used < thresh) + return 1; + } + + if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8)) + return 0; + return 1; +} + +int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type) +{ + u64 alloc_flags = btrfs_get_alloc_profile(trans->fs_info, type); + + return btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE); +} + +static struct btrfs_block_group *do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags) +{ + struct btrfs_block_group *bg; + int ret; + + /* + * Check if we have enough space in the system space info because we + * will need to update device items in the chunk btree and insert a new + * chunk item in the chunk btree as well. This will allocate a new + * system block group if needed. + */ + check_system_chunk(trans, flags); + + bg = btrfs_create_chunk(trans, flags); + if (IS_ERR(bg)) { + ret = PTR_ERR(bg); + goto out; + } + + ret = btrfs_chunk_alloc_add_chunk_item(trans, bg); + /* + * Normally we are not expected to fail with -ENOSPC here, since we have + * previously reserved space in the system space_info and allocated one + * new system chunk if necessary. However there are three exceptions: + * + * 1) We may have enough free space in the system space_info but all the + * existing system block groups have a profile which can not be used + * for extent allocation. + * + * This happens when mounting in degraded mode. For example we have a + * RAID1 filesystem with 2 devices, lose one device and mount the fs + * using the other device in degraded mode. If we then allocate a chunk, + * we may have enough free space in the existing system space_info, but + * none of the block groups can be used for extent allocation since they + * have a RAID1 profile, and because we are in degraded mode with a + * single device, we are forced to allocate a new system chunk with a + * SINGLE profile. Making check_system_chunk() iterate over all system + * block groups and check if they have a usable profile and enough space + * can be slow on very large filesystems, so we tolerate the -ENOSPC and + * try again after forcing allocation of a new system chunk. Like this + * we avoid paying the cost of that search in normal circumstances, when + * we were not mounted in degraded mode; + * + * 2) We had enough free space info the system space_info, and one suitable + * block group to allocate from when we called check_system_chunk() + * above. However right after we called it, the only system block group + * with enough free space got turned into RO mode by a running scrub, + * and in this case we have to allocate a new one and retry. We only + * need do this allocate and retry once, since we have a transaction + * handle and scrub uses the commit root to search for block groups; + * + * 3) We had one system block group with enough free space when we called + * check_system_chunk(), but after that, right before we tried to + * allocate the last extent buffer we needed, a discard operation came + * in and it temporarily removed the last free space entry from the + * block group (discard removes a free space entry, discards it, and + * then adds back the entry to the block group cache). + */ + if (ret == -ENOSPC) { + const u64 sys_flags = btrfs_system_alloc_profile(trans->fs_info); + struct btrfs_block_group *sys_bg; + + sys_bg = btrfs_create_chunk(trans, sys_flags); + if (IS_ERR(sys_bg)) { + ret = PTR_ERR(sys_bg); + btrfs_abort_transaction(trans, ret); + goto out; + } + + ret = btrfs_chunk_alloc_add_chunk_item(trans, sys_bg); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out; + } + + ret = btrfs_chunk_alloc_add_chunk_item(trans, bg); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out; + } + } else if (ret) { + btrfs_abort_transaction(trans, ret); + goto out; + } +out: + btrfs_trans_release_chunk_metadata(trans); + + if (ret) + return ERR_PTR(ret); + + btrfs_get_block_group(bg); + return bg; +} + +/* + * Chunk allocation is done in 2 phases: + * + * 1) Phase 1 - through btrfs_chunk_alloc() we allocate device extents for + * the chunk, the chunk mapping, create its block group and add the items + * that belong in the chunk btree to it - more specifically, we need to + * update device items in the chunk btree and add a new chunk item to it. + * + * 2) Phase 2 - through btrfs_create_pending_block_groups(), we add the block + * group item to the extent btree and the device extent items to the devices + * btree. + * + * This is done to prevent deadlocks. For example when COWing a node from the + * extent btree we are holding a write lock on the node's parent and if we + * trigger chunk allocation and attempted to insert the new block group item + * in the extent btree right way, we could deadlock because the path for the + * insertion can include that parent node. At first glance it seems impossible + * to trigger chunk allocation after starting a transaction since tasks should + * reserve enough transaction units (metadata space), however while that is true + * most of the time, chunk allocation may still be triggered for several reasons: + * + * 1) When reserving metadata, we check if there is enough free space in the + * metadata space_info and therefore don't trigger allocation of a new chunk. + * However later when the task actually tries to COW an extent buffer from + * the extent btree or from the device btree for example, it is forced to + * allocate a new block group (chunk) because the only one that had enough + * free space was just turned to RO mode by a running scrub for example (or + * device replace, block group reclaim thread, etc), so we can not use it + * for allocating an extent and end up being forced to allocate a new one; + * + * 2) Because we only check that the metadata space_info has enough free bytes, + * we end up not allocating a new metadata chunk in that case. However if + * the filesystem was mounted in degraded mode, none of the existing block + * groups might be suitable for extent allocation due to their incompatible + * profile (for e.g. mounting a 2 devices filesystem, where all block groups + * use a RAID1 profile, in degraded mode using a single device). In this case + * when the task attempts to COW some extent buffer of the extent btree for + * example, it will trigger allocation of a new metadata block group with a + * suitable profile (SINGLE profile in the example of the degraded mount of + * the RAID1 filesystem); + * + * 3) The task has reserved enough transaction units / metadata space, but when + * it attempts to COW an extent buffer from the extent or device btree for + * example, it does not find any free extent in any metadata block group, + * therefore forced to try to allocate a new metadata block group. + * This is because some other task allocated all available extents in the + * meanwhile - this typically happens with tasks that don't reserve space + * properly, either intentionally or as a bug. One example where this is + * done intentionally is fsync, as it does not reserve any transaction units + * and ends up allocating a variable number of metadata extents for log + * tree extent buffers; + * + * 4) The task has reserved enough transaction units / metadata space, but right + * before it tries to allocate the last extent buffer it needs, a discard + * operation comes in and, temporarily, removes the last free space entry from + * the only metadata block group that had free space (discard starts by + * removing a free space entry from a block group, then does the discard + * operation and, once it's done, it adds back the free space entry to the + * block group). + * + * We also need this 2 phases setup when adding a device to a filesystem with + * a seed device - we must create new metadata and system chunks without adding + * any of the block group items to the chunk, extent and device btrees. If we + * did not do it this way, we would get ENOSPC when attempting to update those + * btrees, since all the chunks from the seed device are read-only. + * + * Phase 1 does the updates and insertions to the chunk btree because if we had + * it done in phase 2 and have a thundering herd of tasks allocating chunks in + * parallel, we risk having too many system chunks allocated by many tasks if + * many tasks reach phase 1 without the previous ones completing phase 2. In the + * extreme case this leads to exhaustion of the system chunk array in the + * superblock. This is easier to trigger if using a btree node/leaf size of 64K + * and with RAID filesystems (so we have more device items in the chunk btree). + * This has happened before and commit eafa4fd0ad0607 ("btrfs: fix exhaustion of + * the system chunk array due to concurrent allocations") provides more details. + * + * Allocation of system chunks does not happen through this function. A task that + * needs to update the chunk btree (the only btree that uses system chunks), must + * preallocate chunk space by calling either check_system_chunk() or + * btrfs_reserve_chunk_metadata() - the former is used when allocating a data or + * metadata chunk or when removing a chunk, while the later is used before doing + * a modification to the chunk btree - use cases for the later are adding, + * removing and resizing a device as well as relocation of a system chunk. + * See the comment below for more details. + * + * The reservation of system space, done through check_system_chunk(), as well + * as all the updates and insertions into the chunk btree must be done while + * holding fs_info->chunk_mutex. This is important to guarantee that while COWing + * an extent buffer from the chunks btree we never trigger allocation of a new + * system chunk, which would result in a deadlock (trying to lock twice an + * extent buffer of the chunk btree, first time before triggering the chunk + * allocation and the second time during chunk allocation while attempting to + * update the chunks btree). The system chunk array is also updated while holding + * that mutex. The same logic applies to removing chunks - we must reserve system + * space, update the chunk btree and the system chunk array in the superblock + * while holding fs_info->chunk_mutex. + * + * This function, btrfs_chunk_alloc(), belongs to phase 1. + * + * If @force is CHUNK_ALLOC_FORCE: + * - return 1 if it successfully allocates a chunk, + * - return errors including -ENOSPC otherwise. + * If @force is NOT CHUNK_ALLOC_FORCE: + * - return 0 if it doesn't need to allocate a new chunk, + * - return 1 if it successfully allocates a chunk, + * - return errors including -ENOSPC otherwise. + */ +int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags, + enum btrfs_chunk_alloc_enum force) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_space_info *space_info; + struct btrfs_block_group *ret_bg; + bool wait_for_alloc = false; + bool should_alloc = false; + bool from_extent_allocation = false; + int ret = 0; + + if (force == CHUNK_ALLOC_FORCE_FOR_EXTENT) { + from_extent_allocation = true; + force = CHUNK_ALLOC_FORCE; + } + + /* Don't re-enter if we're already allocating a chunk */ + if (trans->allocating_chunk) + return -ENOSPC; + /* + * Allocation of system chunks can not happen through this path, as we + * could end up in a deadlock if we are allocating a data or metadata + * chunk and there is another task modifying the chunk btree. + * + * This is because while we are holding the chunk mutex, we will attempt + * to add the new chunk item to the chunk btree or update an existing + * device item in the chunk btree, while the other task that is modifying + * the chunk btree is attempting to COW an extent buffer while holding a + * lock on it and on its parent - if the COW operation triggers a system + * chunk allocation, then we can deadlock because we are holding the + * chunk mutex and we may need to access that extent buffer or its parent + * in order to add the chunk item or update a device item. + * + * Tasks that want to modify the chunk tree should reserve system space + * before updating the chunk btree, by calling either + * btrfs_reserve_chunk_metadata() or check_system_chunk(). + * It's possible that after a task reserves the space, it still ends up + * here - this happens in the cases described above at do_chunk_alloc(). + * The task will have to either retry or fail. + */ + if (flags & BTRFS_BLOCK_GROUP_SYSTEM) + return -ENOSPC; + + space_info = btrfs_find_space_info(fs_info, flags); + ASSERT(space_info); + + do { + spin_lock(&space_info->lock); + if (force < space_info->force_alloc) + force = space_info->force_alloc; + should_alloc = should_alloc_chunk(fs_info, space_info, force); + if (space_info->full) { + /* No more free physical space */ + if (should_alloc) + ret = -ENOSPC; + else + ret = 0; + spin_unlock(&space_info->lock); + return ret; + } else if (!should_alloc) { + spin_unlock(&space_info->lock); + return 0; + } else if (space_info->chunk_alloc) { + /* + * Someone is already allocating, so we need to block + * until this someone is finished and then loop to + * recheck if we should continue with our allocation + * attempt. + */ + wait_for_alloc = true; + force = CHUNK_ALLOC_NO_FORCE; + spin_unlock(&space_info->lock); + mutex_lock(&fs_info->chunk_mutex); + mutex_unlock(&fs_info->chunk_mutex); + } else { + /* Proceed with allocation */ + space_info->chunk_alloc = 1; + wait_for_alloc = false; + spin_unlock(&space_info->lock); + } + + cond_resched(); + } while (wait_for_alloc); + + mutex_lock(&fs_info->chunk_mutex); + trans->allocating_chunk = true; + + /* + * If we have mixed data/metadata chunks we want to make sure we keep + * allocating mixed chunks instead of individual chunks. + */ + if (btrfs_mixed_space_info(space_info)) + flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA); + + /* + * if we're doing a data chunk, go ahead and make sure that + * we keep a reasonable number of metadata chunks allocated in the + * FS as well. + */ + if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) { + fs_info->data_chunk_allocations++; + if (!(fs_info->data_chunk_allocations % + fs_info->metadata_ratio)) + force_metadata_allocation(fs_info); + } + + ret_bg = do_chunk_alloc(trans, flags); + trans->allocating_chunk = false; + + if (IS_ERR(ret_bg)) { + ret = PTR_ERR(ret_bg); + } else if (from_extent_allocation) { + /* + * New block group is likely to be used soon. Try to activate + * it now. Failure is OK for now. + */ + btrfs_zone_activate(ret_bg); + } + + if (!ret) + btrfs_put_block_group(ret_bg); + + spin_lock(&space_info->lock); + if (ret < 0) { + if (ret == -ENOSPC) + space_info->full = 1; + else + goto out; + } else { + ret = 1; + space_info->max_extent_size = 0; + } + + space_info->force_alloc = CHUNK_ALLOC_NO_FORCE; +out: + space_info->chunk_alloc = 0; + spin_unlock(&space_info->lock); + mutex_unlock(&fs_info->chunk_mutex); + + return ret; +} + +static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type) +{ + u64 num_dev; + + num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max; + if (!num_dev) + num_dev = fs_info->fs_devices->rw_devices; + + return num_dev; +} + +static void reserve_chunk_space(struct btrfs_trans_handle *trans, + u64 bytes, + u64 type) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_space_info *info; + u64 left; + int ret = 0; + + /* + * Needed because we can end up allocating a system chunk and for an + * atomic and race free space reservation in the chunk block reserve. + */ + lockdep_assert_held(&fs_info->chunk_mutex); + + info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM); + spin_lock(&info->lock); + left = info->total_bytes - btrfs_space_info_used(info, true); + spin_unlock(&info->lock); + + if (left < bytes && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) { + btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu", + left, bytes, type); + btrfs_dump_space_info(fs_info, info, 0, 0); + } + + if (left < bytes) { + u64 flags = btrfs_system_alloc_profile(fs_info); + struct btrfs_block_group *bg; + + /* + * Ignore failure to create system chunk. We might end up not + * needing it, as we might not need to COW all nodes/leafs from + * the paths we visit in the chunk tree (they were already COWed + * or created in the current transaction for example). + */ + bg = btrfs_create_chunk(trans, flags); + if (IS_ERR(bg)) { + ret = PTR_ERR(bg); + } else { + /* + * We have a new chunk. We also need to activate it for + * zoned filesystem. + */ + ret = btrfs_zoned_activate_one_bg(fs_info, info, true); + if (ret < 0) + return; + + /* + * If we fail to add the chunk item here, we end up + * trying again at phase 2 of chunk allocation, at + * btrfs_create_pending_block_groups(). So ignore + * any error here. An ENOSPC here could happen, due to + * the cases described at do_chunk_alloc() - the system + * block group we just created was just turned into RO + * mode by a scrub for example, or a running discard + * temporarily removed its free space entries, etc. + */ + btrfs_chunk_alloc_add_chunk_item(trans, bg); + } + } + + if (!ret) { + ret = btrfs_block_rsv_add(fs_info, + &fs_info->chunk_block_rsv, + bytes, BTRFS_RESERVE_NO_FLUSH); + if (!ret) + trans->chunk_bytes_reserved += bytes; + } +} + +/* + * Reserve space in the system space for allocating or removing a chunk. + * The caller must be holding fs_info->chunk_mutex. + */ +void check_system_chunk(struct btrfs_trans_handle *trans, u64 type) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + const u64 num_devs = get_profile_num_devs(fs_info, type); + u64 bytes; + + /* num_devs device items to update and 1 chunk item to add or remove. */ + bytes = btrfs_calc_metadata_size(fs_info, num_devs) + + btrfs_calc_insert_metadata_size(fs_info, 1); + + reserve_chunk_space(trans, bytes, type); +} + +/* + * Reserve space in the system space, if needed, for doing a modification to the + * chunk btree. + * + * @trans: A transaction handle. + * @is_item_insertion: Indicate if the modification is for inserting a new item + * in the chunk btree or if it's for the deletion or update + * of an existing item. + * + * This is used in a context where we need to update the chunk btree outside + * block group allocation and removal, to avoid a deadlock with a concurrent + * task that is allocating a metadata or data block group and therefore needs to + * update the chunk btree while holding the chunk mutex. After the update to the + * chunk btree is done, btrfs_trans_release_chunk_metadata() should be called. + * + */ +void btrfs_reserve_chunk_metadata(struct btrfs_trans_handle *trans, + bool is_item_insertion) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + u64 bytes; + + if (is_item_insertion) + bytes = btrfs_calc_insert_metadata_size(fs_info, 1); + else + bytes = btrfs_calc_metadata_size(fs_info, 1); + + mutex_lock(&fs_info->chunk_mutex); + reserve_chunk_space(trans, bytes, BTRFS_BLOCK_GROUP_SYSTEM); + mutex_unlock(&fs_info->chunk_mutex); +} + +void btrfs_put_block_group_cache(struct btrfs_fs_info *info) +{ + struct btrfs_block_group *block_group; + + block_group = btrfs_lookup_first_block_group(info, 0); + while (block_group) { + btrfs_wait_block_group_cache_done(block_group); + spin_lock(&block_group->lock); + if (test_and_clear_bit(BLOCK_GROUP_FLAG_IREF, + &block_group->runtime_flags)) { + struct inode *inode = block_group->inode; + + block_group->inode = NULL; + spin_unlock(&block_group->lock); + + ASSERT(block_group->io_ctl.inode == NULL); + iput(inode); + } else { + spin_unlock(&block_group->lock); + } + block_group = btrfs_next_block_group(block_group); + } +} + +/* + * Must be called only after stopping all workers, since we could have block + * group caching kthreads running, and therefore they could race with us if we + * freed the block groups before stopping them. + */ +int btrfs_free_block_groups(struct btrfs_fs_info *info) +{ + struct btrfs_block_group *block_group; + struct btrfs_space_info *space_info; + struct btrfs_caching_control *caching_ctl; + struct rb_node *n; + + write_lock(&info->block_group_cache_lock); + while (!list_empty(&info->caching_block_groups)) { + caching_ctl = list_entry(info->caching_block_groups.next, + struct btrfs_caching_control, list); + list_del(&caching_ctl->list); + btrfs_put_caching_control(caching_ctl); + } + write_unlock(&info->block_group_cache_lock); + + spin_lock(&info->unused_bgs_lock); + while (!list_empty(&info->unused_bgs)) { + block_group = list_first_entry(&info->unused_bgs, + struct btrfs_block_group, + bg_list); + list_del_init(&block_group->bg_list); + btrfs_put_block_group(block_group); + } + + while (!list_empty(&info->reclaim_bgs)) { + block_group = list_first_entry(&info->reclaim_bgs, + struct btrfs_block_group, + bg_list); + list_del_init(&block_group->bg_list); + btrfs_put_block_group(block_group); + } + spin_unlock(&info->unused_bgs_lock); + + spin_lock(&info->zone_active_bgs_lock); + while (!list_empty(&info->zone_active_bgs)) { + block_group = list_first_entry(&info->zone_active_bgs, + struct btrfs_block_group, + active_bg_list); + list_del_init(&block_group->active_bg_list); + btrfs_put_block_group(block_group); + } + spin_unlock(&info->zone_active_bgs_lock); + + write_lock(&info->block_group_cache_lock); + while ((n = rb_last(&info->block_group_cache_tree.rb_root)) != NULL) { + block_group = rb_entry(n, struct btrfs_block_group, + cache_node); + rb_erase_cached(&block_group->cache_node, + &info->block_group_cache_tree); + RB_CLEAR_NODE(&block_group->cache_node); + write_unlock(&info->block_group_cache_lock); + + down_write(&block_group->space_info->groups_sem); + list_del(&block_group->list); + up_write(&block_group->space_info->groups_sem); + + /* + * We haven't cached this block group, which means we could + * possibly have excluded extents on this block group. + */ + if (block_group->cached == BTRFS_CACHE_NO || + block_group->cached == BTRFS_CACHE_ERROR) + btrfs_free_excluded_extents(block_group); + + btrfs_remove_free_space_cache(block_group); + ASSERT(block_group->cached != BTRFS_CACHE_STARTED); + ASSERT(list_empty(&block_group->dirty_list)); + ASSERT(list_empty(&block_group->io_list)); + ASSERT(list_empty(&block_group->bg_list)); + ASSERT(refcount_read(&block_group->refs) == 1); + ASSERT(block_group->swap_extents == 0); + btrfs_put_block_group(block_group); + + write_lock(&info->block_group_cache_lock); + } + write_unlock(&info->block_group_cache_lock); + + btrfs_release_global_block_rsv(info); + + while (!list_empty(&info->space_info)) { + space_info = list_entry(info->space_info.next, + struct btrfs_space_info, + list); + + /* + * Do not hide this behind enospc_debug, this is actually + * important and indicates a real bug if this happens. + */ + if (WARN_ON(space_info->bytes_pinned > 0 || + space_info->bytes_may_use > 0)) + btrfs_dump_space_info(info, space_info, 0, 0); + + /* + * If there was a failure to cleanup a log tree, very likely due + * to an IO failure on a writeback attempt of one or more of its + * extent buffers, we could not do proper (and cheap) unaccounting + * of their reserved space, so don't warn on bytes_reserved > 0 in + * that case. + */ + if (!(space_info->flags & BTRFS_BLOCK_GROUP_METADATA) || + !BTRFS_FS_LOG_CLEANUP_ERROR(info)) { + if (WARN_ON(space_info->bytes_reserved > 0)) + btrfs_dump_space_info(info, space_info, 0, 0); + } + + WARN_ON(space_info->reclaim_size > 0); + list_del(&space_info->list); + btrfs_sysfs_remove_space_info(space_info); + } + return 0; +} + +void btrfs_freeze_block_group(struct btrfs_block_group *cache) +{ + atomic_inc(&cache->frozen); +} + +void btrfs_unfreeze_block_group(struct btrfs_block_group *block_group) +{ + struct btrfs_fs_info *fs_info = block_group->fs_info; + struct extent_map_tree *em_tree; + struct extent_map *em; + bool cleanup; + + spin_lock(&block_group->lock); + cleanup = (atomic_dec_and_test(&block_group->frozen) && + test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)); + spin_unlock(&block_group->lock); + + if (cleanup) { + em_tree = &fs_info->mapping_tree; + write_lock(&em_tree->lock); + em = lookup_extent_mapping(em_tree, block_group->start, + 1); + BUG_ON(!em); /* logic error, can't happen */ + remove_extent_mapping(em_tree, em); + write_unlock(&em_tree->lock); + + /* once for us and once for the tree */ + free_extent_map(em); + free_extent_map(em); + + /* + * We may have left one free space entry and other possible + * tasks trimming this block group have left 1 entry each one. + * Free them if any. + */ + btrfs_remove_free_space_cache(block_group); + } +} + +bool btrfs_inc_block_group_swap_extents(struct btrfs_block_group *bg) +{ + bool ret = true; + + spin_lock(&bg->lock); + if (bg->ro) + ret = false; + else + bg->swap_extents++; + spin_unlock(&bg->lock); + + return ret; +} + +void btrfs_dec_block_group_swap_extents(struct btrfs_block_group *bg, int amount) +{ + spin_lock(&bg->lock); + ASSERT(!bg->ro); + ASSERT(bg->swap_extents >= amount); + bg->swap_extents -= amount; + spin_unlock(&bg->lock); +} |