| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Josef Whiter | 9046 | 52.43% | 64 | 15.50% |
| Filipe David Borba Manana | 1412 | 8.18% | 54 | 13.08% |
| Qu Wenruo | 895 | 5.19% | 25 | 6.05% |
| Nikolay Borisov | 779 | 4.51% | 16 | 3.87% |
| Boris Burkov | 757 | 4.39% | 9 | 2.18% |
| Naohiro Aota | 663 | 3.84% | 27 | 6.54% |
| Josef Bacik | 643 | 3.73% | 37 | 8.96% |
| Johannes Thumshirn | 633 | 3.67% | 12 | 2.91% |
| Chris Mason | 510 | 2.96% | 53 | 12.83% |
| Zheng Yan | 462 | 2.68% | 16 | 3.87% |
| David Sterba | 390 | 2.26% | 25 | 6.05% |
| Jeff Mahoney | 301 | 1.74% | 17 | 4.12% |
| Dennis Zhou | 194 | 1.12% | 3 | 0.73% |
| Miao Xie | 146 | 0.85% | 5 | 1.21% |
| Omar Sandoval | 97 | 0.56% | 7 | 1.69% |
| Li Dongyang | 50 | 0.29% | 2 | 0.48% |
| Stefan Behrens | 40 | 0.23% | 5 | 1.21% |
| Liu Bo | 33 | 0.19% | 7 | 1.69% |
| Matt Corallo | 31 | 0.18% | 1 | 0.24% |
| Satoru Takeuchi | 24 | 0.14% | 1 | 0.24% |
| Yan Zheng | 20 | 0.12% | 2 | 0.48% |
| Li Zefan | 19 | 0.11% | 3 | 0.73% |
| Mark Fasheh | 17 | 0.10% | 1 | 0.24% |
| Arne Jansen | 15 | 0.09% | 1 | 0.24% |
| Anand Jain | 14 | 0.08% | 2 | 0.48% |
| Marcos Paulo de Souza | 10 | 0.06% | 1 | 0.24% |
| Gabriel Niebler | 8 | 0.05% | 1 | 0.24% |
| Ilya Dryomov | 8 | 0.05% | 2 | 0.48% |
| Eric Sandeen | 8 | 0.05% | 1 | 0.24% |
| Christoph Hellwig | 7 | 0.04% | 2 | 0.48% |
| David Woodhouse | 5 | 0.03% | 1 | 0.24% |
| Zhao Lei | 4 | 0.02% | 3 | 0.73% |
| Peter Zijlstra | 4 | 0.02% | 1 | 0.24% |
| Mitch Harder | 3 | 0.02% | 1 | 0.24% |
| Alexander Block | 2 | 0.01% | 1 | 0.24% |
| Xiyu Yang | 2 | 0.01% | 1 | 0.24% |
| Lijuan Li | 1 | 0.01% | 1 | 0.24% |
| Xiaoguang Wang | 1 | 0.01% | 1 | 0.24% |
| Randy Dunlap | 1 | 0.01% | 1 | 0.24% |
| Total | 17255 | 413 |
// SPDX-License-Identifier: GPL-2.0 #include <linux/sizes.h> #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" #include "fs.h" #include "accessors.h" #include "extent-tree.h" #ifdef CONFIG_BTRFS_DEBUG int btrfs_should_fragment_free_space(struct btrfs_block_group *block_group) { struct btrfs_fs_info *fs_info = block_group->fs_info; return (btrfs_test_opt(fs_info, FRAGMENT_METADATA) && block_group->flags & BTRFS_BLOCK_GROUP_METADATA) || (btrfs_test_opt(fs_info, FRAGMENT_DATA) && block_group->flags & BTRFS_BLOCK_GROUP_DATA); } #endif /* * 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); kfree(cache->free_space_ctl); btrfs_free_chunk_map(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. * * 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; } static 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 /* * Add a free space range to the in memory free space cache of a block group. * This checks if the range contains super block locations and any such * locations are not added to the free space cache. * * @block_group: The target block group. * @start: Start offset of the range. * @end: End offset of the range (exclusive). * @total_added_ret: Optional pointer to return the total amount of space * added to the block group's free space cache. * * Returns 0 on success or < 0 on error. */ int btrfs_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) { if (!find_first_extent_bit(&info->excluded_extents, start, &extent_start, &extent_end, EXTENT_DIRTY | EXTENT_UPTODATE, NULL)) 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; } /* * Get an arbitrary extent item index / max_index through the block group * * @block_group the block group to sample from * @index: the integral step through the block group to grab from * @max_index: the granularity of the sampling * @key: return value parameter for the item we find * * Pre-conditions on indices: * 0 <= index <= max_index * 0 < max_index * * Returns: 0 on success, 1 if the search didn't yield a useful item, negative * error code on error. */ static int sample_block_group_extent_item(struct btrfs_caching_control *caching_ctl, struct btrfs_block_group *block_group, int index, int max_index, struct btrfs_key *found_key) { struct btrfs_fs_info *fs_info = block_group->fs_info; struct btrfs_root *extent_root; u64 search_offset; u64 search_end = block_group->start + block_group->length; struct btrfs_path *path; struct btrfs_key search_key; int ret = 0; ASSERT(index >= 0); ASSERT(index <= max_index); ASSERT(max_index > 0); lockdep_assert_held(&caching_ctl->mutex); lockdep_assert_held_read(&fs_info->commit_root_sem); path = btrfs_alloc_path(); if (!path) return -ENOMEM; extent_root = btrfs_extent_root(fs_info, max_t(u64, block_group->start, BTRFS_SUPER_INFO_OFFSET)); path->skip_locking = 1; path->search_commit_root = 1; path->reada = READA_FORWARD; search_offset = index * div_u64(block_group->length, max_index); search_key.objectid = block_group->start + search_offset; search_key.type = BTRFS_EXTENT_ITEM_KEY; search_key.offset = 0; btrfs_for_each_slot(extent_root, &search_key, found_key, path, ret) { /* Success; sampled an extent item in the block group */ if (found_key->type == BTRFS_EXTENT_ITEM_KEY && found_key->objectid >= block_group->start && found_key->objectid + found_key->offset <= search_end) break; /* We can't possibly find a valid extent item anymore */ if (found_key->objectid >= search_end) { ret = 1; break; } } lockdep_assert_held(&caching_ctl->mutex); lockdep_assert_held_read(&fs_info->commit_root_sem); btrfs_free_path(path); return ret; } /* * Best effort attempt to compute a block group's size class while caching it. * * @block_group: the block group we are caching * * We cannot infer the size class while adding free space extents, because that * logic doesn't care about contiguous file extents (it doesn't differentiate * between a 100M extent and 100 contiguous 1M extents). So we need to read the * file extent items. Reading all of them is quite wasteful, because usually * only a handful are enough to give a good answer. Therefore, we just grab 5 of * them at even steps through the block group and pick the smallest size class * we see. Since size class is best effort, and not guaranteed in general, * inaccuracy is acceptable. * * To be more explicit about why this algorithm makes sense: * * If we are caching in a block group from disk, then there are three major cases * to consider: * 1. the block group is well behaved and all extents in it are the same size * class. * 2. the block group is mostly one size class with rare exceptions for last * ditch allocations * 3. the block group was populated before size classes and can have a totally * arbitrary mix of size classes. * * In case 1, looking at any extent in the block group will yield the correct * result. For the mixed cases, taking the minimum size class seems like a good * approximation, since gaps from frees will be usable to the size class. For * 2., a small handful of file extents is likely to yield the right answer. For * 3, we can either read every file extent, or admit that this is best effort * anyway and try to stay fast. * * Returns: 0 on success, negative error code on error. */ static int load_block_group_size_class(struct btrfs_caching_control *caching_ctl, struct btrfs_block_group *block_group) { struct btrfs_fs_info *fs_info = block_group->fs_info; struct btrfs_key key; int i; u64 min_size = block_group->length; enum btrfs_block_group_size_class size_class = BTRFS_BG_SZ_NONE; int ret; if (!btrfs_block_group_should_use_size_class(block_group)) return 0; lockdep_assert_held(&caching_ctl->mutex); lockdep_assert_held_read(&fs_info->commit_root_sem); for (i = 0; i < 5; ++i) { ret = sample_block_group_extent_item(caching_ctl, block_group, i, 5, &key); if (ret < 0) goto out; if (ret > 0) continue; min_size = min_t(u64, min_size, key.offset); size_class = btrfs_calc_block_group_size_class(min_size); } if (size_class != BTRFS_BG_SZ_NONE) { spin_lock(&block_group->lock); block_group->size_class = size_class; spin_unlock(&block_group->lock); } out: return ret; } 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 = btrfs_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 = btrfs_add_new_free_space(block_group, last, block_group->start + block_group->length, NULL); out: btrfs_free_path(path); return ret; } static inline void btrfs_free_excluded_extents(const struct btrfs_block_group *bg) { clear_extent_bits(&bg->fs_info->excluded_extents, bg->start, bg->start + bg->length - 1, EXTENT_UPTODATE); } 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); load_block_group_size_class(caching_ctl, block_group); 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); 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, struct btrfs_chunk_map *map) { 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_map; bool remove_rsv = false; block_group = btrfs_lookup_block_group(fs_info, map->start); if (!block_group) return -ENOENT; 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); } block_group->space_info->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 chunk 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_map = (atomic_read(&block_group->frozen) == 0); spin_unlock(&block_group->lock); if (remove_map) btrfs_remove_chunk_map(fs_info, map); out: /* Once for the lookup reference */ btrfs_put_block_group(block_group); if (remove_rsv) btrfs_dec_delayed_refs_rsv_bg_updates(fs_info); 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 btrfs_chunk_map *map; unsigned int num_items; map = btrfs_find_chunk_map(fs_info, chunk_offset, 1); ASSERT(map != NULL); ASSERT(map->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(). */ num_items = 3 + map->num_stripes; btrfs_free_chunk_map(map); 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 an error 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) { LIST_HEAD(retry_list); 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)) { u64 used; 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(&space_info->lock); spin_lock(&block_group->lock); if (btrfs_is_block_group_used(block_group) || 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. * * Also bail out if this is the only block group for its * type, because otherwise we would lose profile * information from fs_info->avail_*_alloc_bits and the * next block group of this type would be created with a * "single" profile (even if we're in a raid fs) because * fs_info->avail_*_alloc_bits would be 0. */ trace_btrfs_skip_unused_block_group(block_group); spin_unlock(&block_group->lock); spin_unlock(&space_info->lock); up_write(&space_info->groups_sem); goto next; } /* * The block group may be unused but there may be space reserved * accounting with the existence of that block group, that is, * space_info->bytes_may_use was incremented by a task but no * space was yet allocated from the block group by the task. * That space may or may not be allocated, as we are generally * pessimistic about space reservation for metadata as well as * for data when using compression (as we reserve space based on * the worst case, when data can't be compressed, and before * actually attempting compression, before starting writeback). * * So check if the total space of the space_info minus the size * of this block group is less than the used space of the * space_info - if that's the case, then it means we have tasks * that might be relying on the block group in order to allocate * extents, and add back the block group to the unused list when * we finish, so that we retry later in case no tasks ended up * needing to allocate extents from the block group. */ used = btrfs_space_info_used(space_info, true); if (space_info->total_bytes - block_group->length < used && block_group->zone_unusable < block_group->length) { /* * Add a reference for the list, compensate for the ref * drop under the "next" label for the * fs_info->unused_bgs list. */ btrfs_get_block_group(block_group); list_add_tail(&block_group->bg_list, &retry_list); trace_btrfs_skip_unused_block_group(block_group); spin_unlock(&block_group->lock); spin_unlock(&space_info->lock); up_write(&space_info->groups_sem); goto next; } spin_unlock(&block_group->lock); spin_unlock(&space_info->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); } list_splice_tail(&retry_list, &fs_info->unused_bgs); spin_unlock(&fs_info->unused_bgs_lock); mutex_unlock(&fs_info->reclaim_bgs_lock); return; flip_async: btrfs_end_transaction(trans); spin_lock(&fs_info->unused_bgs_lock); list_splice_tail(&retry_list, &fs_info->unused_bgs); spin_unlock(&fs_info->unused_bgs_lock); 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; } static 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 = mult_perc(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; } 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; } if (bg->used == 0) { /* * It is possible that we trigger relocation on a block * group as its extents are deleted and it first goes * below the threshold, then shortly after goes empty. * * In this case, relocating it does delete it, but has * some overhead in relocation specific metadata, looking * for the non-existent extents and running some extra * transactions, which we can avoid by using one of the * other mechanisms for dealing with empty block groups. */ if (!btrfs_test_opt(fs_info, DISCARD_ASYNC)) btrfs_mark_bg_unused(bg); spin_unlock(&bg->lock); up_write(&space_info->groups_sem); goto next; } /* * The block group might no longer meet the reclaim condition by * the time we get around to reclaiming it, so to avoid * reclaiming overly full block_groups, skip reclaiming them. * * Since the decision making process also depends on the amount * being freed, pass in a fake giant value to skip that extra * check, which is more meaningful when adding to the list in * the first place. */ if (!should_reclaim_block_group(bg, bg->length)) { 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 btrfs_chunk_map *map; 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]; map = btrfs_find_chunk_map(fs_info, key->objectid, key->offset); if (!map) { btrfs_err(fs_info, "logical %llu len %llu found bg but no related chunk", key->objectid, key->offset); return -ENOENT; } if (map->start != key->objectid || map->chunk_len != key->offset) { btrfs_err(fs_info, "block group %llu len %llu mismatch with chunk %llu len %llu", key->objectid, key->offset, map->start, map->chunk_len); ret = -EUCLEAN; goto out_free_map; } 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 != (map->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 & map->type)); ret = -EUCLEAN; } out_free_map: btrfs_free_chunk_map(map); 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 * @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, u64 physical, u64 **logical, int *naddrs, int *stripe_len) { struct btrfs_chunk_map *map; u64 *buf; u64 bytenr; u64 data_stripe_length; u64 io_stripe_size; int i, nr = 0; int ret = 0; map = btrfs_get_chunk_map(fs_info, chunk_start, 1); if (IS_ERR(map)) return -EIO; data_stripe_length = map->stripe_size; io_stripe_size = BTRFS_STRIPE_LEN; chunk_start = map->start; /* For RAID5/6 adjust to a full IO stripe length */ if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) io_stripe_size = btrfs_stripe_nr_to_offset(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; u32 stripe_nr; u32 offset; int j; if (!in_range(physical, map->stripes[i].physical, data_stripe_length)) continue; stripe_nr = (physical - map->stripes[i].physical) >> BTRFS_STRIPE_LEN_SHIFT; offset = (physical - map->stripes[i].physical) & BTRFS_STRIPE_LEN_MASK; if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) stripe_nr = div_u64(stripe_nr * map->num_stripes + i, 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: btrfs_free_chunk_map(map); 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 = set_extent_bit(&fs_info->excluded_extents, cache->start, cache->start + stripe_len - 1, EXTENT_UPTODATE, NULL); 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, 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 = set_extent_bit(&fs_info->excluded_extents, logical[nr], logical[nr] + len - 1, EXTENT_UPTODATE, NULL); 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); 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) { u64 start = 0; int ret = 0; while (1) { struct btrfs_chunk_map *map; struct btrfs_block_group *bg; /* * btrfs_find_chunk_map() will return the first chunk map * intersecting the range, so setting @length to 1 is enough to * get the first chunk. */ map = btrfs_find_chunk_map(fs_info, start, 1); if (!map) break; bg = btrfs_lookup_block_group(fs_info, map->start); if (!bg) { btrfs_err(fs_info, "chunk start=%llu len=%llu doesn't have corresponding block group", map->start, map->chunk_len); ret = -EUCLEAN; btrfs_free_chunk_map(map); break; } if (bg->start != map->start || bg->length != map->chunk_len || (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) != (map->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", map->start, map->chunk_len, map->type & BTRFS_BLOCK_GROUP_TYPE_MASK, bg->start, bg->length, bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK); ret = -EUCLEAN; btrfs_free_chunk_map(map); btrfs_put_block_group(bg); break; } start = map->start + map->chunk_len; btrfs_free_chunk_map(map); 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->commit_used = cache->used; 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 = btrfs_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 rb_node *node; int ret = 0; for (node = rb_first_cached(&fs_info->mapping_tree); node; node = rb_next(node)) { struct btrfs_chunk_map *map; struct btrfs_block_group *bg; map = rb_entry(node, struct btrfs_chunk_map, rb_node); bg = btrfs_create_block_group_cache(fs_info, map->start); if (!bg) { ret = -ENOMEM; break; } /* Fill dummy cache as FULL */ bg->length = map->chunk_len; bg->flags = map->type; bg->cached = BTRFS_CACHE_FINISHED; bg->used = map->chunk_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; u64 old_commit_used; int ret; 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); old_commit_used = block_group->commit_used; block_group->commit_used = block_group->used; key.objectid = block_group->start; key.type = BTRFS_BLOCK_GROUP_ITEM_KEY; key.offset = block_group->length; spin_unlock(&block_group->lock); ret = btrfs_insert_item(trans, root, &key, &bgi, sizeof(bgi)); if (ret < 0) { spin_lock(&block_group->lock); block_group->commit_used = old_commit_used; spin_unlock(&block_group->lock); } return ret; } 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(trans, 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 btrfs_chunk_map *map; u64 dev_offset; int i; int ret = 0; map = btrfs_get_chunk_map(fs_info, chunk_offset, chunk_size); if (IS_ERR(map)) return PTR_ERR(map); /* * 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, map->stripe_size); if (ret) break; } mutex_unlock(&fs_info->fs_devices->device_list_mutex); btrfs_free_chunk_map(map); 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_dec_delayed_refs_rsv_bg_inserts(fs_info); list_del_init(&block_group->bg_list); clear_bit(BLOCK_GROUP_FLAG_NEW, &block_group->runtime_flags); /* * If the block group is still unused, add it to the list of * unused block groups. The block group may have been created in * order to satisfy a space reservation, in which case the * extent allocation only happens later. But often we don't * actually need to allocate space that we previously reserved, * so the block group may become unused for a long time. For * example for metadata we generally reserve space for a worst * possible scenario, but then don't end up allocating all that * space or none at all (due to no need to COW, extent buffers * were already COWed in the current transaction and still * unwritten, tree heights lower than the maximum possible * height, etc). For data we generally reserve the axact amount * of space we are going to allocate later, the exception is * when using compression, as we must reserve space based on the * uncompressed data size, because the compression is only done * when writeback triggered and we don't know how much space we * are actually going to need, so we reserve the uncompressed * size because the data may be uncompressible in the worst case. */ if (ret == 0) { bool used; spin_lock(&block_group->lock); used = btrfs_is_block_group_used(block_group); spin_unlock(&block_group->lock); if (!used) btrfs_mark_bg_unused(block_group); } } 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 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->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 = btrfs_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)) { cache->space_info->bytes_used += size >> 1; fragment_free_space(cache); } #endif list_add_tail(&cache->bg_list, &trans->new_bgs); btrfs_inc_delayed_refs_rsv_bg_inserts(fs_info); 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 allocation 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; u64 old_commit_used; u64 used; /* * Block group items update can be triggered out of commit transaction * critical section, thus we need a consistent view of used bytes. * We cannot use cache->used directly outside of the spin lock, as it * may be changed. */ spin_lock(&cache->lock); old_commit_used = cache->commit_used; used = cache->used; /* No change in used bytes, can safely skip it. */ if (cache->commit_used == used) { spin_unlock(&cache->lock); return 0; } cache->commit_used = used; spin_unlock(&cache->lock); 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, 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(trans, leaf); fail: btrfs_release_path(path); /* * We didn't update the block group item, need to revert commit_used * unless the block group item didn't exist yet - this is to prevent a * race with a concurrent insertion of the block group item, with * insert_block_group_item(), that happened just after we attempted to * update. In that case we would reset commit_used to 0 just after the * insertion set it to a value greater than 0 - if the block group later * becomes with 0 used bytes, we would incorrectly skip its update. */ if (ret < 0 && ret != -ENOENT) { spin_lock(&cache->lock); cache->commit_used = old_commit_used; spin_unlock(&cache->lock); } 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 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, 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_dec_delayed_refs_rsv_bg_updates(fs_info); /* * 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, U64_MAX); 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_dec_delayed_refs_rsv_bg_updates(fs_info); 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; } 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_space_info *space_info; struct btrfs_block_group *cache; u64 old_val; bool reclaim = false; bool bg_already_dirty = true; int factor; /* 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); cache = btrfs_lookup_block_group(info, bytenr); if (!cache) return -ENOENT; /* An extent can not span multiple block groups. */ ASSERT(bytenr + num_bytes <= cache->start + cache->length); 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); 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; 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_bit(&trans->transaction->pinned_extents, bytenr, bytenr + num_bytes - 1, EXTENT_DIRTY, NULL); } spin_lock(&trans->transaction->dirty_bgs_lock); if (list_empty(&cache->dirty_list)) { list_add_tail(&cache->dirty_list, &trans->transaction->dirty_bgs); bg_already_dirty = false; 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); /* Modified block groups are accounted for in the delayed_refs_rsv. */ if (!bg_already_dirty) btrfs_inc_delayed_refs_rsv_bg_updates(info); return 0; } /* * 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, bool force_wrong_size_class) { struct btrfs_space_info *space_info = cache->space_info; enum btrfs_block_group_size_class size_class; int ret = 0; spin_lock(&space_info->lock); spin_lock(&cache->lock); if (cache->ro) { ret = -EAGAIN; goto out; } if (btrfs_block_group_should_use_size_class(cache)) { size_class = btrfs_calc_block_group_size_class(num_bytes); ret = btrfs_use_block_group_size_class(cache, size_class, force_wrong_size_class); if (ret) goto out; } 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); out: spin_unlock(&cache->lock); spin_unlock(&space_info->lock); return ret; } /* * 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, mult_perc(thresh, 1)); if (sinfo->total_bytes - bytes_used < thresh) return 1; } if (bytes_used + SZ_2M < mult_perc(sinfo->total_bytes, 80)) 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 && (flags & BTRFS_BLOCK_GROUP_DATA)) { /* * 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; if (btrfs_is_zoned(info)) { if (info->active_meta_bg) { btrfs_put_block_group(info->active_meta_bg); info->active_meta_bg = NULL; } if (info->active_system_bg) { btrfs_put_block_group(info->active_system_bg); info->active_system_bg = NULL; } } 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; 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) { struct btrfs_chunk_map *map; map = btrfs_find_chunk_map(fs_info, block_group->start, 1); /* Logic error, can't happen. */ ASSERT(map); btrfs_remove_chunk_map(fs_info, map); /* Once for our lookup reference. */ btrfs_free_chunk_map(map); /* * 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); } enum btrfs_block_group_size_class btrfs_calc_block_group_size_class(u64 size) { if (size <= SZ_128K) return BTRFS_BG_SZ_SMALL; if (size <= SZ_8M) return BTRFS_BG_SZ_MEDIUM; return BTRFS_BG_SZ_LARGE; } /* * Handle a block group allocating an extent in a size class * * @bg: The block group we allocated in. * @size_class: The size class of the allocation. * @force_wrong_size_class: Whether we are desperate enough to allow * mismatched size classes. * * Returns: 0 if the size class was valid for this block_group, -EAGAIN in the * case of a race that leads to the wrong size class without * force_wrong_size_class set. * * find_free_extent will skip block groups with a mismatched size class until * it really needs to avoid ENOSPC. In that case it will set * force_wrong_size_class. However, if a block group is newly allocated and * doesn't yet have a size class, then it is possible for two allocations of * different sizes to race and both try to use it. The loser is caught here and * has to retry. */ int btrfs_use_block_group_size_class(struct btrfs_block_group *bg, enum btrfs_block_group_size_class size_class, bool force_wrong_size_class) { ASSERT(size_class != BTRFS_BG_SZ_NONE); /* The new allocation is in the right size class, do nothing */ if (bg->size_class == size_class) return 0; /* * The new allocation is in a mismatched size class. * This means one of two things: * * 1. Two tasks in find_free_extent for different size_classes raced * and hit the same empty block_group. Make the loser try again. * 2. A call to find_free_extent got desperate enough to set * 'force_wrong_slab'. Don't change the size_class, but allow the * allocation. */ if (bg->size_class != BTRFS_BG_SZ_NONE) { if (force_wrong_size_class) return 0; return -EAGAIN; } /* * The happy new block group case: the new allocation is the first * one in the block_group so we set size_class. */ bg->size_class = size_class; return 0; } bool btrfs_block_group_should_use_size_class(struct btrfs_block_group *bg) { if (btrfs_is_zoned(bg->fs_info)) return false; if (!btrfs_is_block_group_data_only(bg)) return false; return true; }
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with Cregit http://github.com/cregit/cregit
Version 2.0-RC1