| /* |
| * Copyright (C) 2008 Red Hat. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public |
| * License v2 as published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public |
| * License along with this program; if not, write to the |
| * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| * Boston, MA 021110-1307, USA. |
| */ |
| |
| #include <linux/sched.h> |
| #include "ctree.h" |
| #include "free-space-cache.h" |
| #include "transaction.h" |
| |
| struct btrfs_free_space { |
| struct rb_node bytes_index; |
| struct rb_node offset_index; |
| u64 offset; |
| u64 bytes; |
| }; |
| |
| static int tree_insert_offset(struct rb_root *root, u64 offset, |
| struct rb_node *node) |
| { |
| struct rb_node **p = &root->rb_node; |
| struct rb_node *parent = NULL; |
| struct btrfs_free_space *info; |
| |
| while (*p) { |
| parent = *p; |
| info = rb_entry(parent, struct btrfs_free_space, offset_index); |
| |
| if (offset < info->offset) |
| p = &(*p)->rb_left; |
| else if (offset > info->offset) |
| p = &(*p)->rb_right; |
| else |
| return -EEXIST; |
| } |
| |
| rb_link_node(node, parent, p); |
| rb_insert_color(node, root); |
| |
| return 0; |
| } |
| |
| static int tree_insert_bytes(struct rb_root *root, u64 bytes, |
| struct rb_node *node) |
| { |
| struct rb_node **p = &root->rb_node; |
| struct rb_node *parent = NULL; |
| struct btrfs_free_space *info; |
| |
| while (*p) { |
| parent = *p; |
| info = rb_entry(parent, struct btrfs_free_space, bytes_index); |
| |
| if (bytes < info->bytes) |
| p = &(*p)->rb_left; |
| else |
| p = &(*p)->rb_right; |
| } |
| |
| rb_link_node(node, parent, p); |
| rb_insert_color(node, root); |
| |
| return 0; |
| } |
| |
| /* |
| * searches the tree for the given offset. |
| * |
| * fuzzy == 1: this is used for allocations where we are given a hint of where |
| * to look for free space. Because the hint may not be completely on an offset |
| * mark, or the hint may no longer point to free space we need to fudge our |
| * results a bit. So we look for free space starting at or after offset with at |
| * least bytes size. We prefer to find as close to the given offset as we can. |
| * Also if the offset is within a free space range, then we will return the free |
| * space that contains the given offset, which means we can return a free space |
| * chunk with an offset before the provided offset. |
| * |
| * fuzzy == 0: this is just a normal tree search. Give us the free space that |
| * starts at the given offset which is at least bytes size, and if its not there |
| * return NULL. |
| */ |
| static struct btrfs_free_space *tree_search_offset(struct rb_root *root, |
| u64 offset, u64 bytes, |
| int fuzzy) |
| { |
| struct rb_node *n = root->rb_node; |
| struct btrfs_free_space *entry, *ret = NULL; |
| |
| while (n) { |
| entry = rb_entry(n, struct btrfs_free_space, offset_index); |
| |
| if (offset < entry->offset) { |
| if (fuzzy && |
| (!ret || entry->offset < ret->offset) && |
| (bytes <= entry->bytes)) |
| ret = entry; |
| n = n->rb_left; |
| } else if (offset > entry->offset) { |
| if (fuzzy && |
| (entry->offset + entry->bytes - 1) >= offset && |
| bytes <= entry->bytes) { |
| ret = entry; |
| break; |
| } |
| n = n->rb_right; |
| } else { |
| if (bytes > entry->bytes) { |
| n = n->rb_right; |
| continue; |
| } |
| ret = entry; |
| break; |
| } |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * return a chunk at least bytes size, as close to offset that we can get. |
| */ |
| static struct btrfs_free_space *tree_search_bytes(struct rb_root *root, |
| u64 offset, u64 bytes) |
| { |
| struct rb_node *n = root->rb_node; |
| struct btrfs_free_space *entry, *ret = NULL; |
| |
| while (n) { |
| entry = rb_entry(n, struct btrfs_free_space, bytes_index); |
| |
| if (bytes < entry->bytes) { |
| /* |
| * We prefer to get a hole size as close to the size we |
| * are asking for so we don't take small slivers out of |
| * huge holes, but we also want to get as close to the |
| * offset as possible so we don't have a whole lot of |
| * fragmentation. |
| */ |
| if (offset <= entry->offset) { |
| if (!ret) |
| ret = entry; |
| else if (entry->bytes < ret->bytes) |
| ret = entry; |
| else if (entry->offset < ret->offset) |
| ret = entry; |
| } |
| n = n->rb_left; |
| } else if (bytes > entry->bytes) { |
| n = n->rb_right; |
| } else { |
| /* |
| * Ok we may have multiple chunks of the wanted size, |
| * so we don't want to take the first one we find, we |
| * want to take the one closest to our given offset, so |
| * keep searching just in case theres a better match. |
| */ |
| n = n->rb_right; |
| if (offset > entry->offset) |
| continue; |
| else if (!ret || entry->offset < ret->offset) |
| ret = entry; |
| } |
| } |
| |
| return ret; |
| } |
| |
| static void unlink_free_space(struct btrfs_block_group_cache *block_group, |
| struct btrfs_free_space *info) |
| { |
| rb_erase(&info->offset_index, &block_group->free_space_offset); |
| rb_erase(&info->bytes_index, &block_group->free_space_bytes); |
| } |
| |
| static int link_free_space(struct btrfs_block_group_cache *block_group, |
| struct btrfs_free_space *info) |
| { |
| int ret = 0; |
| |
| |
| BUG_ON(!info->bytes); |
| ret = tree_insert_offset(&block_group->free_space_offset, info->offset, |
| &info->offset_index); |
| if (ret) |
| return ret; |
| |
| ret = tree_insert_bytes(&block_group->free_space_bytes, info->bytes, |
| &info->bytes_index); |
| if (ret) |
| return ret; |
| |
| return ret; |
| } |
| |
| int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, |
| u64 offset, u64 bytes) |
| { |
| struct btrfs_free_space *right_info; |
| struct btrfs_free_space *left_info; |
| struct btrfs_free_space *info = NULL; |
| int ret = 0; |
| |
| info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS); |
| if (!info) |
| return -ENOMEM; |
| |
| info->offset = offset; |
| info->bytes = bytes; |
| |
| spin_lock(&block_group->tree_lock); |
| |
| /* |
| * first we want to see if there is free space adjacent to the range we |
| * are adding, if there is remove that struct and add a new one to |
| * cover the entire range |
| */ |
| right_info = tree_search_offset(&block_group->free_space_offset, |
| offset+bytes, 0, 0); |
| left_info = tree_search_offset(&block_group->free_space_offset, |
| offset-1, 0, 1); |
| |
| if (right_info) { |
| unlink_free_space(block_group, right_info); |
| info->bytes += right_info->bytes; |
| kfree(right_info); |
| } |
| |
| if (left_info && left_info->offset + left_info->bytes == offset) { |
| unlink_free_space(block_group, left_info); |
| info->offset = left_info->offset; |
| info->bytes += left_info->bytes; |
| kfree(left_info); |
| } |
| |
| ret = link_free_space(block_group, info); |
| if (ret) |
| kfree(info); |
| |
| spin_unlock(&block_group->tree_lock); |
| |
| if (ret) { |
| printk(KERN_ERR "btrfs: unable to add free space :%d\n", ret); |
| BUG_ON(ret == -EEXIST); |
| } |
| |
| return ret; |
| } |
| |
| int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, |
| u64 offset, u64 bytes) |
| { |
| struct btrfs_free_space *info; |
| int ret = 0; |
| |
| spin_lock(&block_group->tree_lock); |
| |
| info = tree_search_offset(&block_group->free_space_offset, offset, 0, |
| 1); |
| if (info && info->offset == offset) { |
| if (info->bytes < bytes) { |
| printk(KERN_ERR "Found free space at %llu, size %llu," |
| "trying to use %llu\n", |
| (unsigned long long)info->offset, |
| (unsigned long long)info->bytes, |
| (unsigned long long)bytes); |
| WARN_ON(1); |
| ret = -EINVAL; |
| spin_unlock(&block_group->tree_lock); |
| goto out; |
| } |
| unlink_free_space(block_group, info); |
| |
| if (info->bytes == bytes) { |
| kfree(info); |
| spin_unlock(&block_group->tree_lock); |
| goto out; |
| } |
| |
| info->offset += bytes; |
| info->bytes -= bytes; |
| |
| ret = link_free_space(block_group, info); |
| spin_unlock(&block_group->tree_lock); |
| BUG_ON(ret); |
| } else if (info && info->offset < offset && |
| info->offset + info->bytes >= offset + bytes) { |
| u64 old_start = info->offset; |
| /* |
| * we're freeing space in the middle of the info, |
| * this can happen during tree log replay |
| * |
| * first unlink the old info and then |
| * insert it again after the hole we're creating |
| */ |
| unlink_free_space(block_group, info); |
| if (offset + bytes < info->offset + info->bytes) { |
| u64 old_end = info->offset + info->bytes; |
| |
| info->offset = offset + bytes; |
| info->bytes = old_end - info->offset; |
| ret = link_free_space(block_group, info); |
| BUG_ON(ret); |
| } else { |
| /* the hole we're creating ends at the end |
| * of the info struct, just free the info |
| */ |
| kfree(info); |
| } |
| spin_unlock(&block_group->tree_lock); |
| /* step two, insert a new info struct to cover anything |
| * before the hole |
| */ |
| ret = btrfs_add_free_space(block_group, old_start, |
| offset - old_start); |
| BUG_ON(ret); |
| } else { |
| spin_unlock(&block_group->tree_lock); |
| if (!info) { |
| printk(KERN_ERR "couldn't find space %llu to free\n", |
| (unsigned long long)offset); |
| printk(KERN_ERR "cached is %d, offset %llu bytes %llu\n", |
| block_group->cached, |
| (unsigned long long)block_group->key.objectid, |
| (unsigned long long)block_group->key.offset); |
| btrfs_dump_free_space(block_group, bytes); |
| } else if (info) { |
| printk(KERN_ERR "hmm, found offset=%llu bytes=%llu, " |
| "but wanted offset=%llu bytes=%llu\n", |
| (unsigned long long)info->offset, |
| (unsigned long long)info->bytes, |
| (unsigned long long)offset, |
| (unsigned long long)bytes); |
| } |
| WARN_ON(1); |
| } |
| out: |
| return ret; |
| } |
| |
| void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group, |
| u64 bytes) |
| { |
| struct btrfs_free_space *info; |
| struct rb_node *n; |
| int count = 0; |
| |
| for (n = rb_first(&block_group->free_space_offset); n; n = rb_next(n)) { |
| info = rb_entry(n, struct btrfs_free_space, offset_index); |
| if (info->bytes >= bytes) |
| count++; |
| printk(KERN_ERR "entry offset %llu, bytes %llu\n", |
| (unsigned long long)info->offset, |
| (unsigned long long)info->bytes); |
| } |
| printk(KERN_INFO "%d blocks of free space at or bigger than bytes is" |
| "\n", count); |
| } |
| |
| u64 btrfs_block_group_free_space(struct btrfs_block_group_cache *block_group) |
| { |
| struct btrfs_free_space *info; |
| struct rb_node *n; |
| u64 ret = 0; |
| |
| for (n = rb_first(&block_group->free_space_offset); n; |
| n = rb_next(n)) { |
| info = rb_entry(n, struct btrfs_free_space, offset_index); |
| ret += info->bytes; |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * for a given cluster, put all of its extents back into the free |
| * space cache. If the block group passed doesn't match the block group |
| * pointed to by the cluster, someone else raced in and freed the |
| * cluster already. In that case, we just return without changing anything |
| */ |
| static int |
| __btrfs_return_cluster_to_free_space( |
| struct btrfs_block_group_cache *block_group, |
| struct btrfs_free_cluster *cluster) |
| { |
| struct btrfs_free_space *entry; |
| struct rb_node *node; |
| |
| spin_lock(&cluster->lock); |
| if (cluster->block_group != block_group) |
| goto out; |
| |
| cluster->window_start = 0; |
| node = rb_first(&cluster->root); |
| while(node) { |
| entry = rb_entry(node, struct btrfs_free_space, offset_index); |
| node = rb_next(&entry->offset_index); |
| rb_erase(&entry->offset_index, &cluster->root); |
| link_free_space(block_group, entry); |
| } |
| list_del_init(&cluster->block_group_list); |
| |
| btrfs_put_block_group(cluster->block_group); |
| cluster->block_group = NULL; |
| cluster->root.rb_node = NULL; |
| out: |
| spin_unlock(&cluster->lock); |
| return 0; |
| } |
| |
| void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group) |
| { |
| struct btrfs_free_space *info; |
| struct rb_node *node; |
| struct btrfs_free_cluster *cluster; |
| struct btrfs_free_cluster *safe; |
| |
| spin_lock(&block_group->tree_lock); |
| |
| list_for_each_entry_safe(cluster, safe, &block_group->cluster_list, |
| block_group_list) { |
| |
| WARN_ON(cluster->block_group != block_group); |
| __btrfs_return_cluster_to_free_space(block_group, cluster); |
| } |
| |
| while ((node = rb_last(&block_group->free_space_bytes)) != NULL) { |
| info = rb_entry(node, struct btrfs_free_space, bytes_index); |
| unlink_free_space(block_group, info); |
| kfree(info); |
| if (need_resched()) { |
| spin_unlock(&block_group->tree_lock); |
| cond_resched(); |
| spin_lock(&block_group->tree_lock); |
| } |
| } |
| spin_unlock(&block_group->tree_lock); |
| } |
| |
| u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group, |
| u64 offset, u64 bytes, u64 empty_size) |
| { |
| struct btrfs_free_space *entry = NULL; |
| u64 ret = 0; |
| |
| spin_lock(&block_group->tree_lock); |
| entry = tree_search_offset(&block_group->free_space_offset, offset, |
| bytes + empty_size, 1); |
| if (!entry) |
| entry = tree_search_bytes(&block_group->free_space_bytes, |
| offset, bytes + empty_size); |
| if (entry) { |
| unlink_free_space(block_group, entry); |
| ret = entry->offset; |
| entry->offset += bytes; |
| entry->bytes -= bytes; |
| |
| if (!entry->bytes) |
| kfree(entry); |
| else |
| link_free_space(block_group, entry); |
| } |
| spin_unlock(&block_group->tree_lock); |
| |
| return ret; |
| } |
| |
| /* |
| * given a cluster, put all of its extents back into the free space |
| * cache. If a block group is passed, this function will only free |
| * a cluster that belongs to the passed block group. |
| * |
| * Otherwise, it'll get a reference on the block group pointed to by the |
| * cluster and remove the cluster from it. |
| */ |
| int btrfs_return_cluster_to_free_space( |
| struct btrfs_block_group_cache *block_group, |
| struct btrfs_free_cluster *cluster) |
| { |
| int ret; |
| |
| /* first, get a safe pointer to the block group */ |
| spin_lock(&cluster->lock); |
| if (!block_group) { |
| block_group = cluster->block_group; |
| if (!block_group) { |
| spin_unlock(&cluster->lock); |
| return 0; |
| } |
| } else if (cluster->block_group != block_group) { |
| /* someone else has already freed it don't redo their work */ |
| spin_unlock(&cluster->lock); |
| return 0; |
| } |
| atomic_inc(&block_group->count); |
| spin_unlock(&cluster->lock); |
| |
| /* now return any extents the cluster had on it */ |
| spin_lock(&block_group->tree_lock); |
| ret = __btrfs_return_cluster_to_free_space(block_group, cluster); |
| spin_unlock(&block_group->tree_lock); |
| |
| /* finally drop our ref */ |
| btrfs_put_block_group(block_group); |
| return ret; |
| } |
| |
| /* |
| * given a cluster, try to allocate 'bytes' from it, returns 0 |
| * if it couldn't find anything suitably large, or a logical disk offset |
| * if things worked out |
| */ |
| u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group, |
| struct btrfs_free_cluster *cluster, u64 bytes, |
| u64 min_start) |
| { |
| struct btrfs_free_space *entry = NULL; |
| struct rb_node *node; |
| u64 ret = 0; |
| |
| spin_lock(&cluster->lock); |
| if (bytes > cluster->max_size) |
| goto out; |
| |
| if (cluster->block_group != block_group) |
| goto out; |
| |
| node = rb_first(&cluster->root); |
| if (!node) |
| goto out; |
| |
| entry = rb_entry(node, struct btrfs_free_space, offset_index); |
| |
| while(1) { |
| if (entry->bytes < bytes || entry->offset < min_start) { |
| struct rb_node *node; |
| |
| node = rb_next(&entry->offset_index); |
| if (!node) |
| break; |
| entry = rb_entry(node, struct btrfs_free_space, |
| offset_index); |
| continue; |
| } |
| ret = entry->offset; |
| |
| entry->offset += bytes; |
| entry->bytes -= bytes; |
| |
| if (entry->bytes == 0) { |
| rb_erase(&entry->offset_index, &cluster->root); |
| kfree(entry); |
| } |
| break; |
| } |
| out: |
| spin_unlock(&cluster->lock); |
| return ret; |
| } |
| |
| /* |
| * here we try to find a cluster of blocks in a block group. The goal |
| * is to find at least bytes free and up to empty_size + bytes free. |
| * We might not find them all in one contiguous area. |
| * |
| * returns zero and sets up cluster if things worked out, otherwise |
| * it returns -enospc |
| */ |
| int btrfs_find_space_cluster(struct btrfs_trans_handle *trans, |
| struct btrfs_block_group_cache *block_group, |
| struct btrfs_free_cluster *cluster, |
| u64 offset, u64 bytes, u64 empty_size) |
| { |
| struct btrfs_free_space *entry = NULL; |
| struct rb_node *node; |
| struct btrfs_free_space *next; |
| struct btrfs_free_space *last; |
| u64 min_bytes; |
| u64 window_start; |
| u64 window_free; |
| u64 max_extent = 0; |
| int total_retries = 0; |
| int ret; |
| |
| /* for metadata, allow allocates with more holes */ |
| if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) { |
| /* |
| * we want to do larger allocations when we are |
| * flushing out the delayed refs, it helps prevent |
| * making more work as we go along. |
| */ |
| if (trans->transaction->delayed_refs.flushing) |
| min_bytes = max(bytes, (bytes + empty_size) >> 1); |
| else |
| min_bytes = max(bytes, (bytes + empty_size) >> 4); |
| } else |
| min_bytes = max(bytes, (bytes + empty_size) >> 2); |
| |
| spin_lock(&block_group->tree_lock); |
| spin_lock(&cluster->lock); |
| |
| /* someone already found a cluster, hooray */ |
| if (cluster->block_group) { |
| ret = 0; |
| goto out; |
| } |
| again: |
| min_bytes = min(min_bytes, bytes + empty_size); |
| entry = tree_search_bytes(&block_group->free_space_bytes, |
| offset, min_bytes); |
| if (!entry) { |
| ret = -ENOSPC; |
| goto out; |
| } |
| window_start = entry->offset; |
| window_free = entry->bytes; |
| last = entry; |
| max_extent = entry->bytes; |
| |
| while(1) { |
| /* out window is just right, lets fill it */ |
| if (window_free >= bytes + empty_size) |
| break; |
| |
| node = rb_next(&last->offset_index); |
| if (!node) { |
| ret = -ENOSPC; |
| goto out; |
| } |
| next = rb_entry(node, struct btrfs_free_space, offset_index); |
| |
| /* |
| * we haven't filled the empty size and the window is |
| * very large. reset and try again |
| */ |
| if (next->offset - (last->offset + last->bytes) > 128 * 1024 || |
| next->offset - window_start > (bytes + empty_size) * 2) { |
| entry = next; |
| window_start = entry->offset; |
| window_free = entry->bytes; |
| last = entry; |
| max_extent = 0; |
| total_retries++; |
| if (total_retries % 64 == 0) { |
| if (min_bytes >= (bytes + empty_size)) { |
| ret = -ENOSPC; |
| goto out; |
| } |
| /* |
| * grow our allocation a bit, we're not having |
| * much luck |
| */ |
| min_bytes *= 2; |
| goto again; |
| } |
| } else { |
| last = next; |
| window_free += next->bytes; |
| if (entry->bytes > max_extent) |
| max_extent = entry->bytes; |
| } |
| } |
| |
| cluster->window_start = entry->offset; |
| |
| /* |
| * now we've found our entries, pull them out of the free space |
| * cache and put them into the cluster rbtree |
| * |
| * The cluster includes an rbtree, but only uses the offset index |
| * of each free space cache entry. |
| */ |
| while(1) { |
| node = rb_next(&entry->offset_index); |
| unlink_free_space(block_group, entry); |
| ret = tree_insert_offset(&cluster->root, entry->offset, |
| &entry->offset_index); |
| BUG_ON(ret); |
| |
| if (!node || entry == last) |
| break; |
| |
| entry = rb_entry(node, struct btrfs_free_space, offset_index); |
| } |
| ret = 0; |
| cluster->max_size = max_extent; |
| atomic_inc(&block_group->count); |
| list_add_tail(&cluster->block_group_list, &block_group->cluster_list); |
| cluster->block_group = block_group; |
| out: |
| spin_unlock(&cluster->lock); |
| spin_unlock(&block_group->tree_lock); |
| |
| return ret; |
| } |
| |
| /* |
| * simple code to zero out a cluster |
| */ |
| void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster) |
| { |
| spin_lock_init(&cluster->lock); |
| spin_lock_init(&cluster->refill_lock); |
| cluster->root.rb_node = NULL; |
| cluster->max_size = 0; |
| INIT_LIST_HEAD(&cluster->block_group_list); |
| cluster->block_group = NULL; |
| } |
| |