/* * 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/pagemap.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/math64.h> #include "ctree.h" #include "free-space-cache.h" #include "transaction.h" #include "disk-io.h" #include "extent_io.h" #include "inode-map.h" #define BITS_PER_BITMAP (PAGE_CACHE_SIZE * 8) #define MAX_CACHE_BYTES_PER_GIG (32 * 1024) static int link_free_space(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info); static struct inode *__lookup_free_space_inode(struct btrfs_root *root, struct btrfs_path *path, u64 offset) { struct btrfs_key key; struct btrfs_key location; struct btrfs_disk_key disk_key; struct btrfs_free_space_header *header; struct extent_buffer *leaf; struct inode *inode = NULL; int ret; key.objectid = BTRFS_FREE_SPACE_OBJECTID; key.offset = offset; key.type = 0; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) return ERR_PTR(ret); if (ret > 0) { btrfs_release_path(path); return ERR_PTR(-ENOENT); } leaf = path->nodes[0]; header = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_free_space_header); btrfs_free_space_key(leaf, header, &disk_key); btrfs_disk_key_to_cpu(&location, &disk_key); btrfs_release_path(path); inode = btrfs_iget(root->fs_info->sb, &location, root, NULL); if (!inode) return ERR_PTR(-ENOENT); if (IS_ERR(inode)) return inode; if (is_bad_inode(inode)) { iput(inode); return ERR_PTR(-ENOENT); } inode->i_mapping->flags &= ~__GFP_FS; return inode; } struct inode *lookup_free_space_inode(struct btrfs_root *root, struct btrfs_block_group_cache *block_group, struct btrfs_path *path) { struct inode *inode = NULL; spin_lock(&block_group->lock); if (block_group->inode) inode = igrab(block_group->inode); spin_unlock(&block_group->lock); if (inode) return inode; inode = __lookup_free_space_inode(root, path, block_group->key.objectid); if (IS_ERR(inode)) return inode; spin_lock(&block_group->lock); if (!btrfs_fs_closing(root->fs_info)) { block_group->inode = igrab(inode); block_group->iref = 1; } spin_unlock(&block_group->lock); return inode; } int __create_free_space_inode(struct btrfs_root *root, struct btrfs_trans_handle *trans, struct btrfs_path *path, u64 ino, u64 offset) { struct btrfs_key key; struct btrfs_disk_key disk_key; struct btrfs_free_space_header *header; struct btrfs_inode_item *inode_item; struct extent_buffer *leaf; int ret; ret = btrfs_insert_empty_inode(trans, root, path, ino); if (ret) return ret; leaf = path->nodes[0]; inode_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item); btrfs_item_key(leaf, &disk_key, path->slots[0]); memset_extent_buffer(leaf, 0, (unsigned long)inode_item, sizeof(*inode_item)); btrfs_set_inode_generation(leaf, inode_item, trans->transid); btrfs_set_inode_size(leaf, inode_item, 0); btrfs_set_inode_nbytes(leaf, inode_item, 0); btrfs_set_inode_uid(leaf, inode_item, 0); btrfs_set_inode_gid(leaf, inode_item, 0); btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600); btrfs_set_inode_flags(leaf, inode_item, BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC | BTRFS_INODE_NODATASUM); btrfs_set_inode_nlink(leaf, inode_item, 1); btrfs_set_inode_transid(leaf, inode_item, trans->transid); btrfs_set_inode_block_group(leaf, inode_item, offset); btrfs_mark_buffer_dirty(leaf); btrfs_release_path(path); key.objectid = BTRFS_FREE_SPACE_OBJECTID; key.offset = offset; key.type = 0; ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(struct btrfs_free_space_header)); if (ret < 0) { btrfs_release_path(path); return ret; } leaf = path->nodes[0]; header = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_free_space_header); memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header)); btrfs_set_free_space_key(leaf, header, &disk_key); btrfs_mark_buffer_dirty(leaf); btrfs_release_path(path); return 0; } int create_free_space_inode(struct btrfs_root *root, struct btrfs_trans_handle *trans, struct btrfs_block_group_cache *block_group, struct btrfs_path *path) { int ret; u64 ino; ret = btrfs_find_free_objectid(root, &ino); if (ret < 0) return ret; return __create_free_space_inode(root, trans, path, ino, block_group->key.objectid); } int btrfs_truncate_free_space_cache(struct btrfs_root *root, struct btrfs_trans_handle *trans, struct btrfs_path *path, struct inode *inode) { loff_t oldsize; int ret = 0; trans->block_rsv = root->orphan_block_rsv; ret = btrfs_block_rsv_check(trans, root, root->orphan_block_rsv, 0, 5); if (ret) return ret; oldsize = i_size_read(inode); btrfs_i_size_write(inode, 0); truncate_pagecache(inode, oldsize, 0); /* * We don't need an orphan item because truncating the free space cache * will never be split across transactions. */ ret = btrfs_truncate_inode_items(trans, root, inode, 0, BTRFS_EXTENT_DATA_KEY); if (ret) { WARN_ON(1); return ret; } ret = btrfs_update_inode(trans, root, inode); return ret; } static int readahead_cache(struct inode *inode) { struct file_ra_state *ra; unsigned long last_index; ra = kzalloc(sizeof(*ra), GFP_NOFS); if (!ra) return -ENOMEM; file_ra_state_init(ra, inode->i_mapping); last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index); kfree(ra); return 0; } int __load_free_space_cache(struct btrfs_root *root, struct inode *inode, struct btrfs_free_space_ctl *ctl, struct btrfs_path *path, u64 offset) { struct btrfs_free_space_header *header; struct extent_buffer *leaf; struct page *page; u32 *checksums = NULL, *crc; char *disk_crcs = NULL; struct btrfs_key key; struct list_head bitmaps; u64 num_entries; u64 num_bitmaps; u64 generation; u32 cur_crc = ~(u32)0; pgoff_t index = 0; unsigned long first_page_offset; int num_checksums; int ret = 0; INIT_LIST_HEAD(&bitmaps); /* Nothing in the space cache, goodbye */ if (!i_size_read(inode)) goto out; key.objectid = BTRFS_FREE_SPACE_OBJECTID; key.offset = offset; key.type = 0; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; else if (ret > 0) { btrfs_release_path(path); ret = 0; goto out; } ret = -1; leaf = path->nodes[0]; header = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_free_space_header); num_entries = btrfs_free_space_entries(leaf, header); num_bitmaps = btrfs_free_space_bitmaps(leaf, header); generation = btrfs_free_space_generation(leaf, header); btrfs_release_path(path); if (BTRFS_I(inode)->generation != generation) { printk(KERN_ERR "btrfs: free space inode generation (%llu) did" " not match free space cache generation (%llu)\n", (unsigned long long)BTRFS_I(inode)->generation, (unsigned long long)generation); goto out; } if (!num_entries) goto out; /* Setup everything for doing checksumming */ num_checksums = i_size_read(inode) / PAGE_CACHE_SIZE; checksums = crc = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS); if (!checksums) goto out; first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64); disk_crcs = kzalloc(first_page_offset, GFP_NOFS); if (!disk_crcs) goto out; ret = readahead_cache(inode); if (ret) goto out; while (1) { struct btrfs_free_space_entry *entry; struct btrfs_free_space *e; void *addr; unsigned long offset = 0; unsigned long start_offset = 0; int need_loop = 0; if (!num_entries && !num_bitmaps) break; if (index == 0) { start_offset = first_page_offset; offset = start_offset; } page = grab_cache_page(inode->i_mapping, index); if (!page) goto free_cache; if (!PageUptodate(page)) { btrfs_readpage(NULL, page); lock_page(page); if (!PageUptodate(page)) { unlock_page(page); page_cache_release(page); printk(KERN_ERR "btrfs: error reading free " "space cache\n"); goto free_cache; } } addr = kmap(page); if (index == 0) { u64 *gen; memcpy(disk_crcs, addr, first_page_offset); gen = addr + (sizeof(u32) * num_checksums); if (*gen != BTRFS_I(inode)->generation) { printk(KERN_ERR "btrfs: space cache generation" " (%llu) does not match inode (%llu)\n", (unsigned long long)*gen, (unsigned long long) BTRFS_I(inode)->generation); kunmap(page); unlock_page(page); page_cache_release(page); goto free_cache; } crc = (u32 *)disk_crcs; } entry = addr + start_offset; /* First lets check our crc before we do anything fun */ cur_crc = ~(u32)0; cur_crc = btrfs_csum_data(root, addr + start_offset, cur_crc, PAGE_CACHE_SIZE - start_offset); btrfs_csum_final(cur_crc, (char *)&cur_crc); if (cur_crc != *crc) { printk(KERN_ERR "btrfs: crc mismatch for page %lu\n", index); kunmap(page); unlock_page(page); page_cache_release(page); goto free_cache; } crc++; while (1) { if (!num_entries) break; need_loop = 1; e = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS); if (!e) { kunmap(page); unlock_page(page); page_cache_release(page); goto free_cache; } e->offset = le64_to_cpu(entry->offset); e->bytes = le64_to_cpu(entry->bytes); if (!e->bytes) { kunmap(page); kmem_cache_free(btrfs_free_space_cachep, e); unlock_page(page); page_cache_release(page); goto free_cache; } if (entry->type == BTRFS_FREE_SPACE_EXTENT) { spin_lock(&ctl->tree_lock); ret = link_free_space(ctl, e); spin_unlock(&ctl->tree_lock); if (ret) { printk(KERN_ERR "Duplicate entries in " "free space cache, dumping\n"); kunmap(page); unlock_page(page); page_cache_release(page); goto free_cache; } } else { e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS); if (!e->bitmap) { kunmap(page); kmem_cache_free( btrfs_free_space_cachep, e); unlock_page(page); page_cache_release(page); goto free_cache; } spin_lock(&ctl->tree_lock); ret = link_free_space(ctl, e); ctl->total_bitmaps++; ctl->op->recalc_thresholds(ctl); spin_unlock(&ctl->tree_lock); if (ret) { printk(KERN_ERR "Duplicate entries in " "free space cache, dumping\n"); kunmap(page); unlock_page(page); page_cache_release(page); goto free_cache; } list_add_tail(&e->list, &bitmaps); } num_entries--; offset += sizeof(struct btrfs_free_space_entry); if (offset + sizeof(struct btrfs_free_space_entry) >= PAGE_CACHE_SIZE) break; entry++; } /* * We read an entry out of this page, we need to move on to the * next page. */ if (need_loop) { kunmap(page); goto next; } /* * We add the bitmaps at the end of the entries in order that * the bitmap entries are added to the cache. */ e = list_entry(bitmaps.next, struct btrfs_free_space, list); list_del_init(&e->list); memcpy(e->bitmap, addr, PAGE_CACHE_SIZE); kunmap(page); num_bitmaps--; next: unlock_page(page); page_cache_release(page); index++; } ret = 1; out: kfree(checksums); kfree(disk_crcs); return ret; free_cache: __btrfs_remove_free_space_cache(ctl); goto out; } int load_free_space_cache(struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group) { struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; struct btrfs_root *root = fs_info->tree_root; struct inode *inode; struct btrfs_path *path; int ret; bool matched; u64 used = btrfs_block_group_used(&block_group->item); /* * If we're unmounting then just return, since this does a search on the * normal root and not the commit root and we could deadlock. */ if (btrfs_fs_closing(fs_info)) return 0; /* * If this block group has been marked to be cleared for one reason or * another then we can't trust the on disk cache, so just return. */ spin_lock(&block_group->lock); if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) { spin_unlock(&block_group->lock); return 0; } spin_unlock(&block_group->lock); path = btrfs_alloc_path(); if (!path) return 0; inode = lookup_free_space_inode(root, block_group, path); if (IS_ERR(inode)) { btrfs_free_path(path); return 0; } ret = __load_free_space_cache(fs_info->tree_root, inode, ctl, path, block_group->key.objectid); btrfs_free_path(path); if (ret <= 0) goto out; spin_lock(&ctl->tree_lock); matched = (ctl->free_space == (block_group->key.offset - used - block_group->bytes_super)); spin_unlock(&ctl->tree_lock); if (!matched) { __btrfs_remove_free_space_cache(ctl); printk(KERN_ERR "block group %llu has an wrong amount of free " "space\n", block_group->key.objectid); ret = -1; } out: if (ret < 0) { /* This cache is bogus, make sure it gets cleared */ spin_lock(&block_group->lock); block_group->disk_cache_state = BTRFS_DC_CLEAR; spin_unlock(&block_group->lock); ret = 0; printk(KERN_ERR "btrfs: failed to load free space cache " "for block group %llu\n", block_group->key.objectid); } iput(inode); return ret; } int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode, struct btrfs_free_space_ctl *ctl, struct btrfs_block_group_cache *block_group, struct btrfs_trans_handle *trans, struct btrfs_path *path, u64 offset) { struct btrfs_free_space_header *header; struct extent_buffer *leaf; struct rb_node *node; struct list_head *pos, *n; struct page **pages; struct page *page; struct extent_state *cached_state = NULL; struct btrfs_free_cluster *cluster = NULL; struct extent_io_tree *unpin = NULL; struct list_head bitmap_list; struct btrfs_key key; u64 start, end, len; u64 bytes = 0; u32 *crc, *checksums; unsigned long first_page_offset; int index = 0, num_pages = 0; int entries = 0; int bitmaps = 0; int ret = -1; bool next_page = false; bool out_of_space = false; INIT_LIST_HEAD(&bitmap_list); node = rb_first(&ctl->free_space_offset); if (!node) return 0; if (!i_size_read(inode)) return -1; num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; /* Since the first page has all of our checksums and our generation we * need to calculate the offset into the page that we can start writing * our entries. */ first_page_offset = (sizeof(u32) * num_pages) + sizeof(u64); filemap_write_and_wait(inode->i_mapping); btrfs_wait_ordered_range(inode, inode->i_size & ~(root->sectorsize - 1), (u64)-1); /* make sure we don't overflow that first page */ if (first_page_offset + sizeof(struct btrfs_free_space_entry) >= PAGE_CACHE_SIZE) { /* this is really the same as running out of space, where we also return 0 */ printk(KERN_CRIT "Btrfs: free space cache was too big for the crc page\n"); ret = 0; goto out_update; } /* We need a checksum per page. */ crc = checksums = kzalloc(sizeof(u32) * num_pages, GFP_NOFS); if (!crc) return -1; pages = kzalloc(sizeof(struct page *) * num_pages, GFP_NOFS); if (!pages) { kfree(crc); return -1; } /* Get the cluster for this block_group if it exists */ if (block_group && !list_empty(&block_group->cluster_list)) cluster = list_entry(block_group->cluster_list.next, struct btrfs_free_cluster, block_group_list); /* * We shouldn't have switched the pinned extents yet so this is the * right one */ unpin = root->fs_info->pinned_extents; /* * Lock all pages first so we can lock the extent safely. * * NOTE: Because we hold the ref the entire time we're going to write to * the page find_get_page should never fail, so we don't do a check * after find_get_page at this point. Just putting this here so people * know and don't freak out. */ while (index < num_pages) { page = grab_cache_page(inode->i_mapping, index); if (!page) { int i; for (i = 0; i < num_pages; i++) { unlock_page(pages[i]); page_cache_release(pages[i]); } goto out_free; } pages[index] = page; index++; } index = 0; lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1, 0, &cached_state, GFP_NOFS); /* * When searching for pinned extents, we need to start at our start * offset. */ if (block_group) start = block_group->key.objectid; /* Write out the extent entries */ do { struct btrfs_free_space_entry *entry; void *addr; unsigned long offset = 0; unsigned long start_offset = 0; next_page = false; if (index == 0) { start_offset = first_page_offset; offset = start_offset; } if (index >= num_pages) { out_of_space = true; break; } page = pages[index]; addr = kmap(page); entry = addr + start_offset; memset(addr, 0, PAGE_CACHE_SIZE); while (node && !next_page) { struct btrfs_free_space *e; e = rb_entry(node, struct btrfs_free_space, offset_index); entries++; entry->offset = cpu_to_le64(e->offset); entry->bytes = cpu_to_le64(e->bytes); if (e->bitmap) { entry->type = BTRFS_FREE_SPACE_BITMAP; list_add_tail(&e->list, &bitmap_list); bitmaps++; } else { entry->type = BTRFS_FREE_SPACE_EXTENT; } node = rb_next(node); if (!node && cluster) { node = rb_first(&cluster->root); cluster = NULL; } offset += sizeof(struct btrfs_free_space_entry); if (offset + sizeof(struct btrfs_free_space_entry) >= PAGE_CACHE_SIZE) next_page = true; entry++; } /* * We want to add any pinned extents to our free space cache * so we don't leak the space */ while (block_group && !next_page && (start < block_group->key.objectid + block_group->key.offset)) { ret = find_first_extent_bit(unpin, start, &start, &end, EXTENT_DIRTY); if (ret) { ret = 0; break; } /* This pinned extent is out of our range */ if (start >= block_group->key.objectid + block_group->key.offset) break; len = block_group->key.objectid + block_group->key.offset - start; len = min(len, end + 1 - start); entries++; entry->offset = cpu_to_le64(start); entry->bytes = cpu_to_le64(len); entry->type = BTRFS_FREE_SPACE_EXTENT; start = end + 1; offset += sizeof(struct btrfs_free_space_entry); if (offset + sizeof(struct btrfs_free_space_entry) >= PAGE_CACHE_SIZE) next_page = true; entry++; } *crc = ~(u32)0; *crc = btrfs_csum_data(root, addr + start_offset, *crc, PAGE_CACHE_SIZE - start_offset); kunmap(page); btrfs_csum_final(*crc, (char *)crc); crc++; bytes += PAGE_CACHE_SIZE; index++; } while (node || next_page); /* Write out the bitmaps */ list_for_each_safe(pos, n, &bitmap_list) { void *addr; struct btrfs_free_space *entry = list_entry(pos, struct btrfs_free_space, list); if (index >= num_pages) { out_of_space = true; break; } page = pages[index]; addr = kmap(page); memcpy(addr, entry->bitmap, PAGE_CACHE_SIZE); *crc = ~(u32)0; *crc = btrfs_csum_data(root, addr, *crc, PAGE_CACHE_SIZE); kunmap(page); btrfs_csum_final(*crc, (char *)crc); crc++; bytes += PAGE_CACHE_SIZE; list_del_init(&entry->list); index++; } if (out_of_space) { btrfs_drop_pages(pages, num_pages); unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1, &cached_state, GFP_NOFS); ret = 0; goto out_free; } /* Zero out the rest of the pages just to make sure */ while (index < num_pages) { void *addr; page = pages[index]; addr = kmap(page); memset(addr, 0, PAGE_CACHE_SIZE); kunmap(page); bytes += PAGE_CACHE_SIZE; index++; } /* Write the checksums and trans id to the first page */ { void *addr; u64 *gen; page = pages[0]; addr = kmap(page); memcpy(addr, checksums, sizeof(u32) * num_pages); gen = addr + (sizeof(u32) * num_pages); *gen = trans->transid; kunmap(page); } ret = btrfs_dirty_pages(root, inode, pages, num_pages, 0, bytes, &cached_state); btrfs_drop_pages(pages, num_pages); unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1, &cached_state, GFP_NOFS); if (ret) { ret = 0; goto out_free; } BTRFS_I(inode)->generation = trans->transid; filemap_write_and_wait(inode->i_mapping); key.objectid = BTRFS_FREE_SPACE_OBJECTID; key.offset = offset; key.type = 0; ret = btrfs_search_slot(trans, root, &key, path, 1, 1); if (ret < 0) { ret = -1; clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1, EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING, 0, 0, NULL, GFP_NOFS); goto out_free; } leaf = path->nodes[0]; if (ret > 0) { struct btrfs_key found_key; BUG_ON(!path->slots[0]); path->slots[0]--; btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID || found_key.offset != offset) { ret = -1; clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1, EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING, 0, 0, NULL, GFP_NOFS); btrfs_release_path(path); goto out_free; } } header = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_free_space_header); btrfs_set_free_space_entries(leaf, header, entries); btrfs_set_free_space_bitmaps(leaf, header, bitmaps); btrfs_set_free_space_generation(leaf, header, trans->transid); btrfs_mark_buffer_dirty(leaf); btrfs_release_path(path); ret = 1; out_free: kfree(checksums); kfree(pages); out_update: if (ret != 1) { invalidate_inode_pages2_range(inode->i_mapping, 0, index); BTRFS_I(inode)->generation = 0; } btrfs_update_inode(trans, root, inode); return ret; } int btrfs_write_out_cache(struct btrfs_root *root, struct btrfs_trans_handle *trans, struct btrfs_block_group_cache *block_group, struct btrfs_path *path) { struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; struct inode *inode; int ret = 0; root = root->fs_info->tree_root; spin_lock(&block_group->lock); if (block_group->disk_cache_state < BTRFS_DC_SETUP) { spin_unlock(&block_group->lock); return 0; } spin_unlock(&block_group->lock); inode = lookup_free_space_inode(root, block_group, path); if (IS_ERR(inode)) return 0; ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans, path, block_group->key.objectid); if (ret < 0) { spin_lock(&block_group->lock); block_group->disk_cache_state = BTRFS_DC_ERROR; spin_unlock(&block_group->lock); ret = 0; printk(KERN_ERR "btrfs: failed to write free space cace " "for block group %llu\n", block_group->key.objectid); } iput(inode); return ret; } static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit, u64 offset) { BUG_ON(offset < bitmap_start); offset -= bitmap_start; return (unsigned long)(div_u64(offset, unit)); } static inline unsigned long bytes_to_bits(u64 bytes, u32 unit) { return (unsigned long)(div_u64(bytes, unit)); } static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl, u64 offset) { u64 bitmap_start; u64 bytes_per_bitmap; bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit; bitmap_start = offset - ctl->start; bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap); bitmap_start *= bytes_per_bitmap; bitmap_start += ctl->start; return bitmap_start; } static int tree_insert_offset(struct rb_root *root, u64 offset, struct rb_node *node, int bitmap) { 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 { /* * we could have a bitmap entry and an extent entry * share the same offset. If this is the case, we want * the extent entry to always be found first if we do a * linear search through the tree, since we want to have * the quickest allocation time, and allocating from an * extent is faster than allocating from a bitmap. So * if we're inserting a bitmap and we find an entry at * this offset, we want to go right, or after this entry * logically. If we are inserting an extent and we've * found a bitmap, we want to go left, or before * logically. */ if (bitmap) { if (info->bitmap) { WARN_ON_ONCE(1); return -EEXIST; } p = &(*p)->rb_right; } else { if (!info->bitmap) { WARN_ON_ONCE(1); return -EEXIST; } p = &(*p)->rb_left; } } } rb_link_node(node, parent, p); rb_insert_color(node, root); return 0; } /* * searches the tree for the given offset. * * fuzzy - If this is set, then we are trying to make an allocation, and we just * want a section that has at least bytes size and comes at or after the given * offset. */ static struct btrfs_free_space * tree_search_offset(struct btrfs_free_space_ctl *ctl, u64 offset, int bitmap_only, int fuzzy) { struct rb_node *n = ctl->free_space_offset.rb_node; struct btrfs_free_space *entry, *prev = NULL; /* find entry that is closest to the 'offset' */ while (1) { if (!n) { entry = NULL; break; } entry = rb_entry(n, struct btrfs_free_space, offset_index); prev = entry; if (offset < entry->offset) n = n->rb_left; else if (offset > entry->offset) n = n->rb_right; else break; } if (bitmap_only) { if (!entry) return NULL; if (entry->bitmap) return entry; /* * bitmap entry and extent entry may share same offset, * in that case, bitmap entry comes after extent entry. */ n = rb_next(n); if (!n) return NULL; entry = rb_entry(n, struct btrfs_free_space, offset_index); if (entry->offset != offset) return NULL; WARN_ON(!entry->bitmap); return entry; } else if (entry) { if (entry->bitmap) { /* * if previous extent entry covers the offset, * we should return it instead of the bitmap entry */ n = &entry->offset_index; while (1) { n = rb_prev(n); if (!n) break; prev = rb_entry(n, struct btrfs_free_space, offset_index); if (!prev->bitmap) { if (prev->offset + prev->bytes > offset) entry = prev; break; } } } return entry; } if (!prev) return NULL; /* find last entry before the 'offset' */ entry = prev; if (entry->offset > offset) { n = rb_prev(&entry->offset_index); if (n) { entry = rb_entry(n, struct btrfs_free_space, offset_index); BUG_ON(entry->offset > offset); } else { if (fuzzy) return entry; else return NULL; } } if (entry->bitmap) { n = &entry->offset_index; while (1) { n = rb_prev(n); if (!n) break; prev = rb_entry(n, struct btrfs_free_space, offset_index); if (!prev->bitmap) { if (prev->offset + prev->bytes > offset) return prev; break; } } if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset) return entry; } else if (entry->offset + entry->bytes > offset) return entry; if (!fuzzy) return NULL; while (1) { if (entry->bitmap) { if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset) break; } else { if (entry->offset + entry->bytes > offset) break; } n = rb_next(&entry->offset_index); if (!n) return NULL; entry = rb_entry(n, struct btrfs_free_space, offset_index); } return entry; } static inline void __unlink_free_space(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info) { rb_erase(&info->offset_index, &ctl->free_space_offset); ctl->free_extents--; } static void unlink_free_space(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info) { __unlink_free_space(ctl, info); ctl->free_space -= info->bytes; } static int link_free_space(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info) { int ret = 0; BUG_ON(!info->bitmap && !info->bytes); ret = tree_insert_offset(&ctl->free_space_offset, info->offset, &info->offset_index, (info->bitmap != NULL)); if (ret) return ret; ctl->free_space += info->bytes; ctl->free_extents++; return ret; } static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl) { struct btrfs_block_group_cache *block_group = ctl->private; u64 max_bytes; u64 bitmap_bytes; u64 extent_bytes; u64 size = block_group->key.offset; u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize; int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg); BUG_ON(ctl->total_bitmaps > max_bitmaps); /* * The goal is to keep the total amount of memory used per 1gb of space * at or below 32k, so we need to adjust how much memory we allow to be * used by extent based free space tracking */ if (size < 1024 * 1024 * 1024) max_bytes = MAX_CACHE_BYTES_PER_GIG; else max_bytes = MAX_CACHE_BYTES_PER_GIG * div64_u64(size, 1024 * 1024 * 1024); /* * we want to account for 1 more bitmap than what we have so we can make * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as * we add more bitmaps. */ bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE; if (bitmap_bytes >= max_bytes) { ctl->extents_thresh = 0; return; } /* * we want the extent entry threshold to always be at most 1/2 the maxw * bytes we can have, or whatever is less than that. */ extent_bytes = max_bytes - bitmap_bytes; extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2)); ctl->extents_thresh = div64_u64(extent_bytes, (sizeof(struct btrfs_free_space))); } static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info, u64 offset, u64 bytes) { unsigned long start, count; start = offset_to_bit(info->offset, ctl->unit, offset); count = bytes_to_bits(bytes, ctl->unit); BUG_ON(start + count > BITS_PER_BITMAP); bitmap_clear(info->bitmap, start, count); info->bytes -= bytes; ctl->free_space -= bytes; } static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info, u64 offset, u64 bytes) { unsigned long start, count; start = offset_to_bit(info->offset, ctl->unit, offset); count = bytes_to_bits(bytes, ctl->unit); BUG_ON(start + count > BITS_PER_BITMAP); bitmap_set(info->bitmap, start, count); info->bytes += bytes; ctl->free_space += bytes; } static int search_bitmap(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *bitmap_info, u64 *offset, u64 *bytes) { unsigned long found_bits = 0; unsigned long bits, i; unsigned long next_zero; i = offset_to_bit(bitmap_info->offset, ctl->unit, max_t(u64, *offset, bitmap_info->offset)); bits = bytes_to_bits(*bytes, ctl->unit); for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i); i < BITS_PER_BITMAP; i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) { next_zero = find_next_zero_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i); if ((next_zero - i) >= bits) { found_bits = next_zero - i; break; } i = next_zero; } if (found_bits) { *offset = (u64)(i * ctl->unit) + bitmap_info->offset; *bytes = (u64)(found_bits) * ctl->unit; return 0; } return -1; } static struct btrfs_free_space * find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes) { struct btrfs_free_space *entry; struct rb_node *node; int ret; if (!ctl->free_space_offset.rb_node) return NULL; entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1); if (!entry) return NULL; for (node = &entry->offset_index; node; node = rb_next(node)) { entry = rb_entry(node, struct btrfs_free_space, offset_index); if (entry->bytes < *bytes) continue; if (entry->bitmap) { ret = search_bitmap(ctl, entry, offset, bytes); if (!ret) return entry; continue; } *offset = entry->offset; *bytes = entry->bytes; return entry; } return NULL; } static void add_new_bitmap(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info, u64 offset) { info->offset = offset_to_bitmap(ctl, offset); info->bytes = 0; link_free_space(ctl, info); ctl->total_bitmaps++; ctl->op->recalc_thresholds(ctl); } static void free_bitmap(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *bitmap_info) { unlink_free_space(ctl, bitmap_info); kfree(bitmap_info->bitmap); kmem_cache_free(btrfs_free_space_cachep, bitmap_info); ctl->total_bitmaps--; ctl->op->recalc_thresholds(ctl); } static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *bitmap_info, u64 *offset, u64 *bytes) { u64 end; u64 search_start, search_bytes; int ret; again: end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1; /* * XXX - this can go away after a few releases. * * since the only user of btrfs_remove_free_space is the tree logging * stuff, and the only way to test that is under crash conditions, we * want to have this debug stuff here just in case somethings not * working. Search the bitmap for the space we are trying to use to * make sure its actually there. If its not there then we need to stop * because something has gone wrong. */ search_start = *offset; search_bytes = *bytes; search_bytes = min(search_bytes, end - search_start + 1); ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes); BUG_ON(ret < 0 || search_start != *offset); if (*offset > bitmap_info->offset && *offset + *bytes > end) { bitmap_clear_bits(ctl, bitmap_info, *offset, end - *offset + 1); *bytes -= end - *offset + 1; *offset = end + 1; } else if (*offset >= bitmap_info->offset && *offset + *bytes <= end) { bitmap_clear_bits(ctl, bitmap_info, *offset, *bytes); *bytes = 0; } if (*bytes) { struct rb_node *next = rb_next(&bitmap_info->offset_index); if (!bitmap_info->bytes) free_bitmap(ctl, bitmap_info); /* * no entry after this bitmap, but we still have bytes to * remove, so something has gone wrong. */ if (!next) return -EINVAL; bitmap_info = rb_entry(next, struct btrfs_free_space, offset_index); /* * if the next entry isn't a bitmap we need to return to let the * extent stuff do its work. */ if (!bitmap_info->bitmap) return -EAGAIN; /* * Ok the next item is a bitmap, but it may not actually hold * the information for the rest of this free space stuff, so * look for it, and if we don't find it return so we can try * everything over again. */ search_start = *offset; search_bytes = *bytes; ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes); if (ret < 0 || search_start != *offset) return -EAGAIN; goto again; } else if (!bitmap_info->bytes) free_bitmap(ctl, bitmap_info); return 0; } static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info, u64 offset, u64 bytes) { u64 bytes_to_set = 0; u64 end; end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit); bytes_to_set = min(end - offset, bytes); bitmap_set_bits(ctl, info, offset, bytes_to_set); return bytes_to_set; } static bool use_bitmap(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info) { struct btrfs_block_group_cache *block_group = ctl->private; /* * If we are below the extents threshold then we can add this as an * extent, and don't have to deal with the bitmap */ if (ctl->free_extents < ctl->extents_thresh) { /* * If this block group has some small extents we don't want to * use up all of our free slots in the cache with them, we want * to reserve them to larger extents, however if we have plent * of cache left then go ahead an dadd them, no sense in adding * the overhead of a bitmap if we don't have to. */ if (info->bytes <= block_group->sectorsize * 4) { if (ctl->free_extents * 2 <= ctl->extents_thresh) return false; } else { return false; } } /* * some block groups are so tiny they can't be enveloped by a bitmap, so * don't even bother to create a bitmap for this */ if (BITS_PER_BITMAP * block_group->sectorsize > block_group->key.offset) return false; return true; } static struct btrfs_free_space_op free_space_op = { .recalc_thresholds = recalculate_thresholds, .use_bitmap = use_bitmap, }; static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info) { struct btrfs_free_space *bitmap_info; struct btrfs_block_group_cache *block_group = NULL; int added = 0; u64 bytes, offset, bytes_added; int ret; bytes = info->bytes; offset = info->offset; if (!ctl->op->use_bitmap(ctl, info)) return 0; if (ctl->op == &free_space_op) block_group = ctl->private; again: /* * Since we link bitmaps right into the cluster we need to see if we * have a cluster here, and if so and it has our bitmap we need to add * the free space to that bitmap. */ if (block_group && !list_empty(&block_group->cluster_list)) { struct btrfs_free_cluster *cluster; struct rb_node *node; struct btrfs_free_space *entry; cluster = list_entry(block_group->cluster_list.next, struct btrfs_free_cluster, block_group_list); spin_lock(&cluster->lock); node = rb_first(&cluster->root); if (!node) { spin_unlock(&cluster->lock); goto no_cluster_bitmap; } entry = rb_entry(node, struct btrfs_free_space, offset_index); if (!entry->bitmap) { spin_unlock(&cluster->lock); goto no_cluster_bitmap; } if (entry->offset == offset_to_bitmap(ctl, offset)) { bytes_added = add_bytes_to_bitmap(ctl, entry, offset, bytes); bytes -= bytes_added; offset += bytes_added; } spin_unlock(&cluster->lock); if (!bytes) { ret = 1; goto out; } } no_cluster_bitmap: bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 1, 0); if (!bitmap_info) { BUG_ON(added); goto new_bitmap; } bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes); bytes -= bytes_added; offset += bytes_added; added = 0; if (!bytes) { ret = 1; goto out; } else goto again; new_bitmap: if (info && info->bitmap) { add_new_bitmap(ctl, info, offset); added = 1; info = NULL; goto again; } else { spin_unlock(&ctl->tree_lock); /* no pre-allocated info, allocate a new one */ if (!info) { info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS); if (!info) { spin_lock(&ctl->tree_lock); ret = -ENOMEM; goto out; } } /* allocate the bitmap */ info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS); spin_lock(&ctl->tree_lock); if (!info->bitmap) { ret = -ENOMEM; goto out; } goto again; } out: if (info) { if (info->bitmap) kfree(info->bitmap); kmem_cache_free(btrfs_free_space_cachep, info); } return ret; } static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl, struct btrfs_free_space *info, bool update_stat) { struct btrfs_free_space *left_info; struct btrfs_free_space *right_info; bool merged = false; u64 offset = info->offset; u64 bytes = info->bytes; /* * 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(ctl, offset + bytes, 0, 0); if (right_info && rb_prev(&right_info->offset_index)) left_info = rb_entry(rb_prev(&right_info->offset_index), struct btrfs_free_space, offset_index); else left_info = tree_search_offset(ctl, offset - 1, 0, 0); if (right_info && !right_info->bitmap) { if (update_stat) unlink_free_space(ctl, right_info); else __unlink_free_space(ctl, right_info); info->bytes += right_info->bytes; kmem_cache_free(btrfs_free_space_cachep, right_info); merged = true; } if (left_info && !left_info->bitmap && left_info->offset + left_info->bytes == offset) { if (update_stat) unlink_free_space(ctl, left_info); else __unlink_free_space(ctl, left_info); info->offset = left_info->offset; info->bytes += left_info->bytes; kmem_cache_free(btrfs_free_space_cachep, left_info); merged = true; } return merged; } int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl, u64 offset, u64 bytes) { struct btrfs_free_space *info; int ret = 0; info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS); if (!info) return -ENOMEM; info->offset = offset; info->bytes = bytes; spin_lock(&ctl->tree_lock); if (try_merge_free_space(ctl, info, true)) goto link; /* * There was no extent directly to the left or right of this new * extent then we know we're going to have to allocate a new extent, so * before we do that see if we need to drop this into a bitmap */ ret = insert_into_bitmap(ctl, info); if (ret < 0) { goto out; } else if (ret) { ret = 0; goto out; } link: ret = link_free_space(ctl, info); if (ret) kmem_cache_free(btrfs_free_space_cachep, info); out: spin_unlock(&ctl->tree_lock); if (ret) { printk(KERN_CRIT "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_ctl *ctl = block_group->free_space_ctl; struct btrfs_free_space *info; struct btrfs_free_space *next_info = NULL; int ret = 0; spin_lock(&ctl->tree_lock); again: info = tree_search_offset(ctl, offset, 0, 0); if (!info) { /* * oops didn't find an extent that matched the space we wanted * to remove, look for a bitmap instead */ info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 1, 0); if (!info) { WARN_ON(1); goto out_lock; } } if (info->bytes < bytes && rb_next(&info->offset_index)) { u64 end; next_info = rb_entry(rb_next(&info->offset_index), struct btrfs_free_space, offset_index); if (next_info->bitmap) end = next_info->offset + BITS_PER_BITMAP * ctl->unit - 1; else end = next_info->offset + next_info->bytes; if (next_info->bytes < bytes || next_info->offset > offset || offset > end) { printk(KERN_CRIT "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; goto out_lock; } info = next_info; } if (info->bytes == bytes) { unlink_free_space(ctl, info); if (info->bitmap) { kfree(info->bitmap); ctl->total_bitmaps--; } kmem_cache_free(btrfs_free_space_cachep, info); goto out_lock; } if (!info->bitmap && info->offset == offset) { unlink_free_space(ctl, info); info->offset += bytes; info->bytes -= bytes; link_free_space(ctl, info); goto out_lock; } if (!info->bitmap && 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(ctl, 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(ctl, info); WARN_ON(ret); if (ret) goto out_lock; } else { /* the hole we're creating ends at the end * of the info struct, just free the info */ kmem_cache_free(btrfs_free_space_cachep, info); } spin_unlock(&ctl->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); WARN_ON(ret); goto out; } ret = remove_from_bitmap(ctl, info, &offset, &bytes); if (ret == -EAGAIN) goto again; BUG_ON(ret); out_lock: spin_unlock(&ctl->tree_lock); out: return ret; } void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group, u64 bytes) { struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; struct btrfs_free_space *info; struct rb_node *n; int count = 0; for (n = rb_first(&ctl->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_CRIT "entry offset %llu, bytes %llu, bitmap %s\n", (unsigned long long)info->offset, (unsigned long long)info->bytes, (info->bitmap) ? "yes" : "no"); } printk(KERN_INFO "block group has cluster?: %s\n", list_empty(&block_group->cluster_list) ? "no" : "yes"); printk(KERN_INFO "%d blocks of free space at or bigger than bytes is" "\n", count); } void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group) { struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; spin_lock_init(&ctl->tree_lock); ctl->unit = block_group->sectorsize; ctl->start = block_group->key.objectid; ctl->private = block_group; ctl->op = &free_space_op; /* * we only want to have 32k of ram per block group for keeping * track of free space, and if we pass 1/2 of that we want to * start converting things over to using bitmaps */ ctl->extents_thresh = ((1024 * 32) / 2) / sizeof(struct btrfs_free_space); } /* * 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_ctl *ctl = block_group->free_space_ctl; struct btrfs_free_space *entry; struct rb_node *node; spin_lock(&cluster->lock); if (cluster->block_group != block_group) goto out; cluster->block_group = NULL; cluster->window_start = 0; list_del_init(&cluster->block_group_list); node = rb_first(&cluster->root); while (node) { bool bitmap; entry = rb_entry(node, struct btrfs_free_space, offset_index); node = rb_next(&entry->offset_index); rb_erase(&entry->offset_index, &cluster->root); bitmap = (entry->bitmap != NULL); if (!bitmap) try_merge_free_space(ctl, entry, false); tree_insert_offset(&ctl->free_space_offset, entry->offset, &entry->offset_index, bitmap); } cluster->root = RB_ROOT; out: spin_unlock(&cluster->lock); btrfs_put_block_group(block_group); return 0; } void __btrfs_remove_free_space_cache_locked(struct btrfs_free_space_ctl *ctl) { struct btrfs_free_space *info; struct rb_node *node; while ((node = rb_last(&ctl->free_space_offset)) != NULL) { info = rb_entry(node, struct btrfs_free_space, offset_index); unlink_free_space(ctl, info); kfree(info->bitmap); kmem_cache_free(btrfs_free_space_cachep, info); if (need_resched()) { spin_unlock(&ctl->tree_lock); cond_resched(); spin_lock(&ctl->tree_lock); } } } void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl) { spin_lock(&ctl->tree_lock); __btrfs_remove_free_space_cache_locked(ctl); spin_unlock(&ctl->tree_lock); } void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group) { struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; struct btrfs_free_cluster *cluster; struct list_head *head; spin_lock(&ctl->tree_lock); while ((head = block_group->cluster_list.next) != &block_group->cluster_list) { cluster = list_entry(head, struct btrfs_free_cluster, block_group_list); WARN_ON(cluster->block_group != block_group); __btrfs_return_cluster_to_free_space(block_group, cluster); if (need_resched()) { spin_unlock(&ctl->tree_lock); cond_resched(); spin_lock(&ctl->tree_lock); } } __btrfs_remove_free_space_cache_locked(ctl); spin_unlock(&ctl->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_ctl *ctl = block_group->free_space_ctl; struct btrfs_free_space *entry = NULL; u64 bytes_search = bytes + empty_size; u64 ret = 0; spin_lock(&ctl->tree_lock); entry = find_free_space(ctl, &offset, &bytes_search); if (!entry) goto out; ret = offset; if (entry->bitmap) { bitmap_clear_bits(ctl, entry, offset, bytes); if (!entry->bytes) free_bitmap(ctl, entry); } else { unlink_free_space(ctl, entry); entry->offset += bytes; entry->bytes -= bytes; if (!entry->bytes) kmem_cache_free(btrfs_free_space_cachep, entry); else link_free_space(ctl, entry); } out: spin_unlock(&ctl->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) { struct btrfs_free_space_ctl *ctl; 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); ctl = block_group->free_space_ctl; /* now return any extents the cluster had on it */ spin_lock(&ctl->tree_lock); ret = __btrfs_return_cluster_to_free_space(block_group, cluster); spin_unlock(&ctl->tree_lock); /* finally drop our ref */ btrfs_put_block_group(block_group); return ret; } static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group, struct btrfs_free_cluster *cluster, struct btrfs_free_space *entry, u64 bytes, u64 min_start) { struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; int err; u64 search_start = cluster->window_start; u64 search_bytes = bytes; u64 ret = 0; search_start = min_start; search_bytes = bytes; err = search_bitmap(ctl, entry, &search_start, &search_bytes); if (err) return 0; ret = search_start; bitmap_clear_bits(ctl, entry, ret, bytes); 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_ctl *ctl = block_group->free_space_ctl; 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->bitmap && entry->offset < min_start)) { node = rb_next(&entry->offset_index); if (!node) break; entry = rb_entry(node, struct btrfs_free_space, offset_index); continue; } if (entry->bitmap) { ret = btrfs_alloc_from_bitmap(block_group, cluster, entry, bytes, min_start); if (ret == 0) { node = rb_next(&entry->offset_index); if (!node) break; entry = rb_entry(node, struct btrfs_free_space, offset_index); continue; } } else { ret = entry->offset; entry->offset += bytes; entry->bytes -= bytes; } if (entry->bytes == 0) rb_erase(&entry->offset_index, &cluster->root); break; } out: spin_unlock(&cluster->lock); if (!ret) return 0; spin_lock(&ctl->tree_lock); ctl->free_space -= bytes; if (entry->bytes == 0) { ctl->free_extents--; if (entry->bitmap) { kfree(entry->bitmap); ctl->total_bitmaps--; ctl->op->recalc_thresholds(ctl); } kmem_cache_free(btrfs_free_space_cachep, entry); } spin_unlock(&ctl->tree_lock); return ret; } static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group, struct btrfs_free_space *entry, struct btrfs_free_cluster *cluster, u64 offset, u64 bytes, u64 min_bytes) { struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; unsigned long next_zero; unsigned long i; unsigned long search_bits; unsigned long total_bits; unsigned long found_bits; unsigned long start = 0; unsigned long total_found = 0; int ret; bool found = false; i = offset_to_bit(entry->offset, block_group->sectorsize, max_t(u64, offset, entry->offset)); search_bits = bytes_to_bits(bytes, block_group->sectorsize); total_bits = bytes_to_bits(min_bytes, block_group->sectorsize); again: found_bits = 0; for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i); i < BITS_PER_BITMAP; i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) { next_zero = find_next_zero_bit(entry->bitmap, BITS_PER_BITMAP, i); if (next_zero - i >= search_bits) { found_bits = next_zero - i; break; } i = next_zero; } if (!found_bits) return -ENOSPC; if (!found) { start = i; found = true; } total_found += found_bits; if (cluster->max_size < found_bits * block_group->sectorsize) cluster->max_size = found_bits * block_group->sectorsize; if (total_found < total_bits) { i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, next_zero); if (i - start > total_bits * 2) { total_found = 0; cluster->max_size = 0; found = false; } goto again; } cluster->window_start = start * block_group->sectorsize + entry->offset; rb_erase(&entry->offset_index, &ctl->free_space_offset); ret = tree_insert_offset(&cluster->root, entry->offset, &entry->offset_index, 1); BUG_ON(ret); return 0; } /* * This searches the block group for just extents to fill the cluster with. */ static noinline int setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group, struct btrfs_free_cluster *cluster, struct list_head *bitmaps, u64 offset, u64 bytes, u64 min_bytes) { struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; struct btrfs_free_space *first = NULL; struct btrfs_free_space *entry = NULL; struct btrfs_free_space *prev = NULL; struct btrfs_free_space *last; struct rb_node *node; u64 window_start; u64 window_free; u64 max_extent; u64 max_gap = 128 * 1024; entry = tree_search_offset(ctl, offset, 0, 1); if (!entry) return -ENOSPC; /* * We don't want bitmaps, so just move along until we find a normal * extent entry. */ while (entry->bitmap) { if (list_empty(&entry->list)) list_add_tail(&entry->list, bitmaps); node = rb_next(&entry->offset_index); if (!node) return -ENOSPC; entry = rb_entry(node, struct btrfs_free_space, offset_index); } window_start = entry->offset; window_free = entry->bytes; max_extent = entry->bytes; first = entry; last = entry; prev = entry; while (window_free <= min_bytes) { node = rb_next(&entry->offset_index); if (!node) return -ENOSPC; entry = rb_entry(node, struct btrfs_free_space, offset_index); if (entry->bitmap) { if (list_empty(&entry->list)) list_add_tail(&entry->list, bitmaps); continue; } /* * we haven't filled the empty size and the window is * very large. reset and try again */ if (entry->offset - (prev->offset + prev->bytes) > max_gap || entry->offset - window_start > (min_bytes * 2)) { first = entry; window_start = entry->offset; window_free = entry->bytes; last = entry; max_extent = entry->bytes; } else { last = entry; window_free += entry->bytes; if (entry->bytes > max_extent) max_extent = entry->bytes; } prev = entry; } cluster->window_start = first->offset; node = &first->offset_index; /* * now we've found our entries, pull them out of the free space * cache and put them into the cluster rbtree */ do { int ret; entry = rb_entry(node, struct btrfs_free_space, offset_index); node = rb_next(&entry->offset_index); if (entry->bitmap) continue; rb_erase(&entry->offset_index, &ctl->free_space_offset); ret = tree_insert_offset(&cluster->root, entry->offset, &entry->offset_index, 0); BUG_ON(ret); } while (node && entry != last); cluster->max_size = max_extent; return 0; } /* * This specifically looks for bitmaps that may work in the cluster, we assume * that we have already failed to find extents that will work. */ static noinline int setup_cluster_bitmap(struct btrfs_block_group_cache *block_group, struct btrfs_free_cluster *cluster, struct list_head *bitmaps, u64 offset, u64 bytes, u64 min_bytes) { struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; struct btrfs_free_space *entry; struct rb_node *node; int ret = -ENOSPC; if (ctl->total_bitmaps == 0) return -ENOSPC; /* * First check our cached list of bitmaps and see if there is an entry * here that will work. */ list_for_each_entry(entry, bitmaps, list) { if (entry->bytes < min_bytes) continue; ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset, bytes, min_bytes); if (!ret) return 0; } /* * If we do have entries on our list and we are here then we didn't find * anything, so go ahead and get the next entry after the last entry in * this list and start the search from there. */ if (!list_empty(bitmaps)) { entry = list_entry(bitmaps->prev, struct btrfs_free_space, list); node = rb_next(&entry->offset_index); if (!node) return -ENOSPC; entry = rb_entry(node, struct btrfs_free_space, offset_index); goto search; } entry = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 0, 1); if (!entry) return -ENOSPC; search: node = &entry->offset_index; do { entry = rb_entry(node, struct btrfs_free_space, offset_index); node = rb_next(&entry->offset_index); if (!entry->bitmap) continue; if (entry->bytes < min_bytes) continue; ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset, bytes, min_bytes); } while (ret && node); 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_root *root, struct btrfs_block_group_cache *block_group, struct btrfs_free_cluster *cluster, u64 offset, u64 bytes, u64 empty_size) { struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; struct list_head bitmaps; struct btrfs_free_space *entry, *tmp; u64 min_bytes; int ret; /* for metadata, allow allocates with more holes */ if (btrfs_test_opt(root, SSD_SPREAD)) { min_bytes = bytes + empty_size; } else 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(&ctl->tree_lock); /* * If we know we don't have enough space to make a cluster don't even * bother doing all the work to try and find one. */ if (ctl->free_space < min_bytes) { spin_unlock(&ctl->tree_lock); return -ENOSPC; } spin_lock(&cluster->lock); /* someone already found a cluster, hooray */ if (cluster->block_group) { ret = 0; goto out; } INIT_LIST_HEAD(&bitmaps); ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset, bytes, min_bytes); if (ret) ret = setup_cluster_bitmap(block_group, cluster, &bitmaps, offset, bytes, min_bytes); /* Clear our temporary list */ list_for_each_entry_safe(entry, tmp, &bitmaps, list) list_del_init(&entry->list); if (!ret) { 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(&ctl->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_ROOT; cluster->max_size = 0; INIT_LIST_HEAD(&cluster->block_group_list); cluster->block_group = NULL; } int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group, u64 *trimmed, u64 start, u64 end, u64 minlen) { struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; struct btrfs_free_space *entry = NULL; struct btrfs_fs_info *fs_info = block_group->fs_info; u64 bytes = 0; u64 actually_trimmed; int ret = 0; *trimmed = 0; while (start < end) { spin_lock(&ctl->tree_lock); if (ctl->free_space < minlen) { spin_unlock(&ctl->tree_lock); break; } entry = tree_search_offset(ctl, start, 0, 1); if (!entry) entry = tree_search_offset(ctl, offset_to_bitmap(ctl, start), 1, 1); if (!entry || entry->offset >= end) { spin_unlock(&ctl->tree_lock); break; } if (entry->bitmap) { ret = search_bitmap(ctl, entry, &start, &bytes); if (!ret) { if (start >= end) { spin_unlock(&ctl->tree_lock); break; } bytes = min(bytes, end - start); bitmap_clear_bits(ctl, entry, start, bytes); if (entry->bytes == 0) free_bitmap(ctl, entry); } else { start = entry->offset + BITS_PER_BITMAP * block_group->sectorsize; spin_unlock(&ctl->tree_lock); ret = 0; continue; } } else { start = entry->offset; bytes = min(entry->bytes, end - start); unlink_free_space(ctl, entry); kmem_cache_free(btrfs_free_space_cachep, entry); } spin_unlock(&ctl->tree_lock); if (bytes >= minlen) { int update_ret; update_ret = btrfs_update_reserved_bytes(block_group, bytes, 1, 1); ret = btrfs_error_discard_extent(fs_info->extent_root, start, bytes, &actually_trimmed); btrfs_add_free_space(block_group, start, bytes); if (!update_ret) btrfs_update_reserved_bytes(block_group, bytes, 0, 1); if (ret) break; *trimmed += actually_trimmed; } start += bytes; bytes = 0; if (fatal_signal_pending(current)) { ret = -ERESTARTSYS; break; } cond_resched(); } return ret; } /* * Find the left-most item in the cache tree, and then return the * smallest inode number in the item. * * Note: the returned inode number may not be the smallest one in * the tree, if the left-most item is a bitmap. */ u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root) { struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl; struct btrfs_free_space *entry = NULL; u64 ino = 0; spin_lock(&ctl->tree_lock); if (RB_EMPTY_ROOT(&ctl->free_space_offset)) goto out; entry = rb_entry(rb_first(&ctl->free_space_offset), struct btrfs_free_space, offset_index); if (!entry->bitmap) { ino = entry->offset; unlink_free_space(ctl, entry); entry->offset++; entry->bytes--; if (!entry->bytes) kmem_cache_free(btrfs_free_space_cachep, entry); else link_free_space(ctl, entry); } else { u64 offset = 0; u64 count = 1; int ret; ret = search_bitmap(ctl, entry, &offset, &count); BUG_ON(ret); ino = offset; bitmap_clear_bits(ctl, entry, offset, 1); if (entry->bytes == 0) free_bitmap(ctl, entry); } out: spin_unlock(&ctl->tree_lock); return ino; } struct inode *lookup_free_ino_inode(struct btrfs_root *root, struct btrfs_path *path) { struct inode *inode = NULL; spin_lock(&root->cache_lock); if (root->cache_inode) inode = igrab(root->cache_inode); spin_unlock(&root->cache_lock); if (inode) return inode; inode = __lookup_free_space_inode(root, path, 0); if (IS_ERR(inode)) return inode; spin_lock(&root->cache_lock); if (!btrfs_fs_closing(root->fs_info)) root->cache_inode = igrab(inode); spin_unlock(&root->cache_lock); return inode; } int create_free_ino_inode(struct btrfs_root *root, struct btrfs_trans_handle *trans, struct btrfs_path *path) { return __create_free_space_inode(root, trans, path, BTRFS_FREE_INO_OBJECTID, 0); } int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root) { struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; struct btrfs_path *path; struct inode *inode; int ret = 0; u64 root_gen = btrfs_root_generation(&root->root_item); if (!btrfs_test_opt(root, INODE_MAP_CACHE)) return 0; /* * If we're unmounting then just return, since this does a search on the * normal root and not the commit root and we could deadlock. */ if (btrfs_fs_closing(fs_info)) return 0; path = btrfs_alloc_path(); if (!path) return 0; inode = lookup_free_ino_inode(root, path); if (IS_ERR(inode)) goto out; if (root_gen != BTRFS_I(inode)->generation) goto out_put; ret = __load_free_space_cache(root, inode, ctl, path, 0); if (ret < 0) printk(KERN_ERR "btrfs: failed to load free ino cache for " "root %llu\n", root->root_key.objectid); out_put: iput(inode); out: btrfs_free_path(path); return ret; } int btrfs_write_out_ino_cache(struct btrfs_root *root, struct btrfs_trans_handle *trans, struct btrfs_path *path) { struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; struct inode *inode; int ret; if (!btrfs_test_opt(root, INODE_MAP_CACHE)) return 0; inode = lookup_free_ino_inode(root, path); if (IS_ERR(inode)) return 0; ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0); if (ret < 0) printk(KERN_ERR "btrfs: failed to write free ino cache " "for root %llu\n", root->root_key.objectid); iput(inode); return ret; }