diff options
Diffstat (limited to 'fs/btrfs/free-space-cache.c')
| -rw-r--r-- | fs/btrfs/free-space-cache.c | 3653 |
1 files changed, 3653 insertions, 0 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c new file mode 100644 index 000000000..9dbe5b548 --- /dev/null +++ b/fs/btrfs/free-space-cache.c @@ -0,0 +1,3653 @@ +/* + * 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 <linux/ratelimit.h> +#include "ctree.h" +#include "free-space-cache.h" +#include "transaction.h" +#include "disk-io.h" +#include "extent_io.h" +#include "inode-map.h" +#include "volumes.h" + +#define BITS_PER_BITMAP (PAGE_CACHE_SIZE * 8) +#define MAX_CACHE_BYTES_PER_GIG (32 * 1024) + +struct btrfs_trim_range { + u64 start; + u64 bytes; + struct list_head list; +}; + +static int link_free_space(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info); +static void unlink_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); + } + + mapping_set_gfp_mask(inode->i_mapping, + mapping_gfp_mask(inode->i_mapping) & + ~(__GFP_FS | __GFP_HIGHMEM)); + + 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; + u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW; + + 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_I(inode)->flags & flags) == flags)) { + btrfs_info(root->fs_info, + "Old style space inode found, converting."); + BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM | + BTRFS_INODE_NODATACOW; + block_group->disk_cache_state = BTRFS_DC_CLEAR; + } + + if (!block_group->iref) { + block_group->inode = igrab(inode); + block_group->iref = 1; + } + spin_unlock(&block_group->lock); + + return inode; +} + +static 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; + u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC; + int ret; + + ret = btrfs_insert_empty_inode(trans, root, path, ino); + if (ret) + return ret; + + /* We inline crc's for the free disk space cache */ + if (ino != BTRFS_FREE_INO_OBJECTID) + flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW; + + 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, flags); + 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_check_trunc_cache_free_space(struct btrfs_root *root, + struct btrfs_block_rsv *rsv) +{ + u64 needed_bytes; + int ret; + + /* 1 for slack space, 1 for updating the inode */ + needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) + + btrfs_calc_trans_metadata_size(root, 1); + + spin_lock(&rsv->lock); + if (rsv->reserved < needed_bytes) + ret = -ENOSPC; + else + ret = 0; + spin_unlock(&rsv->lock); + return ret; +} + +int btrfs_truncate_free_space_cache(struct btrfs_root *root, + struct btrfs_trans_handle *trans, + struct btrfs_block_group_cache *block_group, + struct inode *inode) +{ + int ret = 0; + struct btrfs_path *path = btrfs_alloc_path(); + + if (!path) { + ret = -ENOMEM; + goto fail; + } + + if (block_group) { + mutex_lock(&trans->transaction->cache_write_mutex); + if (!list_empty(&block_group->io_list)) { + list_del_init(&block_group->io_list); + + btrfs_wait_cache_io(root, trans, block_group, + &block_group->io_ctl, path, + block_group->key.objectid); + btrfs_put_block_group(block_group); + } + + /* + * now that we've truncated the cache away, its no longer + * setup or written + */ + spin_lock(&block_group->lock); + block_group->disk_cache_state = BTRFS_DC_CLEAR; + spin_unlock(&block_group->lock); + } + btrfs_free_path(path); + + btrfs_i_size_write(inode, 0); + truncate_pagecache(inode, 0); + + /* + * We don't need an orphan item because truncating the free space cache + * will never be split across transactions. + * We don't need to check for -EAGAIN because we're a free space + * cache inode + */ + ret = btrfs_truncate_inode_items(trans, root, inode, + 0, BTRFS_EXTENT_DATA_KEY); + if (ret) { + mutex_unlock(&trans->transaction->cache_write_mutex); + btrfs_abort_transaction(trans, root, ret); + return ret; + } + + ret = btrfs_update_inode(trans, root, inode); + + if (block_group) + mutex_unlock(&trans->transaction->cache_write_mutex); + +fail: + if (ret) + btrfs_abort_transaction(trans, root, ret); + + 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; +} + +static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode, + struct btrfs_root *root, int write) +{ + int num_pages; + int check_crcs = 0; + + num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_CACHE_SIZE); + + if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID) + check_crcs = 1; + + /* Make sure we can fit our crcs into the first page */ + if (write && check_crcs && + (num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE) + return -ENOSPC; + + memset(io_ctl, 0, sizeof(struct btrfs_io_ctl)); + + io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS); + if (!io_ctl->pages) + return -ENOMEM; + + io_ctl->num_pages = num_pages; + io_ctl->root = root; + io_ctl->check_crcs = check_crcs; + io_ctl->inode = inode; + + return 0; +} + +static void io_ctl_free(struct btrfs_io_ctl *io_ctl) +{ + kfree(io_ctl->pages); + io_ctl->pages = NULL; +} + +static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl) +{ + if (io_ctl->cur) { + io_ctl->cur = NULL; + io_ctl->orig = NULL; + } +} + +static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear) +{ + ASSERT(io_ctl->index < io_ctl->num_pages); + io_ctl->page = io_ctl->pages[io_ctl->index++]; + io_ctl->cur = page_address(io_ctl->page); + io_ctl->orig = io_ctl->cur; + io_ctl->size = PAGE_CACHE_SIZE; + if (clear) + memset(io_ctl->cur, 0, PAGE_CACHE_SIZE); +} + +static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl) +{ + int i; + + io_ctl_unmap_page(io_ctl); + + for (i = 0; i < io_ctl->num_pages; i++) { + if (io_ctl->pages[i]) { + ClearPageChecked(io_ctl->pages[i]); + unlock_page(io_ctl->pages[i]); + page_cache_release(io_ctl->pages[i]); + } + } +} + +static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, struct inode *inode, + int uptodate) +{ + struct page *page; + gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping); + int i; + + for (i = 0; i < io_ctl->num_pages; i++) { + page = find_or_create_page(inode->i_mapping, i, mask); + if (!page) { + io_ctl_drop_pages(io_ctl); + return -ENOMEM; + } + io_ctl->pages[i] = page; + if (uptodate && !PageUptodate(page)) { + btrfs_readpage(NULL, page); + lock_page(page); + if (!PageUptodate(page)) { + btrfs_err(BTRFS_I(inode)->root->fs_info, + "error reading free space cache"); + io_ctl_drop_pages(io_ctl); + return -EIO; + } + } + } + + for (i = 0; i < io_ctl->num_pages; i++) { + clear_page_dirty_for_io(io_ctl->pages[i]); + set_page_extent_mapped(io_ctl->pages[i]); + } + + return 0; +} + +static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation) +{ + __le64 *val; + + io_ctl_map_page(io_ctl, 1); + + /* + * Skip the csum areas. If we don't check crcs then we just have a + * 64bit chunk at the front of the first page. + */ + if (io_ctl->check_crcs) { + io_ctl->cur += (sizeof(u32) * io_ctl->num_pages); + io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages); + } else { + io_ctl->cur += sizeof(u64); + io_ctl->size -= sizeof(u64) * 2; + } + + val = io_ctl->cur; + *val = cpu_to_le64(generation); + io_ctl->cur += sizeof(u64); +} + +static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation) +{ + __le64 *gen; + + /* + * Skip the crc area. If we don't check crcs then we just have a 64bit + * chunk at the front of the first page. + */ + if (io_ctl->check_crcs) { + io_ctl->cur += sizeof(u32) * io_ctl->num_pages; + io_ctl->size -= sizeof(u64) + + (sizeof(u32) * io_ctl->num_pages); + } else { + io_ctl->cur += sizeof(u64); + io_ctl->size -= sizeof(u64) * 2; + } + + gen = io_ctl->cur; + if (le64_to_cpu(*gen) != generation) { + printk_ratelimited(KERN_ERR "BTRFS: space cache generation " + "(%Lu) does not match inode (%Lu)\n", *gen, + generation); + io_ctl_unmap_page(io_ctl); + return -EIO; + } + io_ctl->cur += sizeof(u64); + return 0; +} + +static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index) +{ + u32 *tmp; + u32 crc = ~(u32)0; + unsigned offset = 0; + + if (!io_ctl->check_crcs) { + io_ctl_unmap_page(io_ctl); + return; + } + + if (index == 0) + offset = sizeof(u32) * io_ctl->num_pages; + + crc = btrfs_csum_data(io_ctl->orig + offset, crc, + PAGE_CACHE_SIZE - offset); + btrfs_csum_final(crc, (char *)&crc); + io_ctl_unmap_page(io_ctl); + tmp = page_address(io_ctl->pages[0]); + tmp += index; + *tmp = crc; +} + +static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index) +{ + u32 *tmp, val; + u32 crc = ~(u32)0; + unsigned offset = 0; + + if (!io_ctl->check_crcs) { + io_ctl_map_page(io_ctl, 0); + return 0; + } + + if (index == 0) + offset = sizeof(u32) * io_ctl->num_pages; + + tmp = page_address(io_ctl->pages[0]); + tmp += index; + val = *tmp; + + io_ctl_map_page(io_ctl, 0); + crc = btrfs_csum_data(io_ctl->orig + offset, crc, + PAGE_CACHE_SIZE - offset); + btrfs_csum_final(crc, (char *)&crc); + if (val != crc) { + printk_ratelimited(KERN_ERR "BTRFS: csum mismatch on free " + "space cache\n"); + io_ctl_unmap_page(io_ctl); + return -EIO; + } + + return 0; +} + +static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes, + void *bitmap) +{ + struct btrfs_free_space_entry *entry; + + if (!io_ctl->cur) + return -ENOSPC; + + entry = io_ctl->cur; + entry->offset = cpu_to_le64(offset); + entry->bytes = cpu_to_le64(bytes); + entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP : + BTRFS_FREE_SPACE_EXTENT; + io_ctl->cur += sizeof(struct btrfs_free_space_entry); + io_ctl->size -= sizeof(struct btrfs_free_space_entry); + + if (io_ctl->size >= sizeof(struct btrfs_free_space_entry)) + return 0; + + io_ctl_set_crc(io_ctl, io_ctl->index - 1); + + /* No more pages to map */ + if (io_ctl->index >= io_ctl->num_pages) + return 0; + + /* map the next page */ + io_ctl_map_page(io_ctl, 1); + return 0; +} + +static int io_ctl_add_bitmap(struct btrfs_io_ctl *io_ctl, void *bitmap) +{ + if (!io_ctl->cur) + return -ENOSPC; + + /* + * If we aren't at the start of the current page, unmap this one and + * map the next one if there is any left. + */ + if (io_ctl->cur != io_ctl->orig) { + io_ctl_set_crc(io_ctl, io_ctl->index - 1); + if (io_ctl->index >= io_ctl->num_pages) + return -ENOSPC; + io_ctl_map_page(io_ctl, 0); + } + + memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE); + io_ctl_set_crc(io_ctl, io_ctl->index - 1); + if (io_ctl->index < io_ctl->num_pages) + io_ctl_map_page(io_ctl, 0); + return 0; +} + +static void io_ctl_zero_remaining_pages(struct btrfs_io_ctl *io_ctl) +{ + /* + * If we're not on the boundary we know we've modified the page and we + * need to crc the page. + */ + if (io_ctl->cur != io_ctl->orig) + io_ctl_set_crc(io_ctl, io_ctl->index - 1); + else + io_ctl_unmap_page(io_ctl); + + while (io_ctl->index < io_ctl->num_pages) { + io_ctl_map_page(io_ctl, 1); + io_ctl_set_crc(io_ctl, io_ctl->index - 1); + } +} + +static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl, + struct btrfs_free_space *entry, u8 *type) +{ + struct btrfs_free_space_entry *e; + int ret; + + if (!io_ctl->cur) { + ret = io_ctl_check_crc(io_ctl, io_ctl->index); + if (ret) + return ret; + } + + e = io_ctl->cur; + entry->offset = le64_to_cpu(e->offset); + entry->bytes = le64_to_cpu(e->bytes); + *type = e->type; + io_ctl->cur += sizeof(struct btrfs_free_space_entry); + io_ctl->size -= sizeof(struct btrfs_free_space_entry); + + if (io_ctl->size >= sizeof(struct btrfs_free_space_entry)) + return 0; + + io_ctl_unmap_page(io_ctl); + + return 0; +} + +static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl, + struct btrfs_free_space *entry) +{ + int ret; + + ret = io_ctl_check_crc(io_ctl, io_ctl->index); + if (ret) + return ret; + + memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE); + io_ctl_unmap_page(io_ctl); + + return 0; +} + +/* + * Since we attach pinned extents after the fact we can have contiguous sections + * of free space that are split up in entries. This poses a problem with the + * tree logging stuff since it could have allocated across what appears to be 2 + * entries since we would have merged the entries when adding the pinned extents + * back to the free space cache. So run through the space cache that we just + * loaded and merge contiguous entries. This will make the log replay stuff not + * blow up and it will make for nicer allocator behavior. + */ +static void merge_space_tree(struct btrfs_free_space_ctl *ctl) +{ + struct btrfs_free_space *e, *prev = NULL; + struct rb_node *n; + +again: + spin_lock(&ctl->tree_lock); + for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) { + e = rb_entry(n, struct btrfs_free_space, offset_index); + if (!prev) + goto next; + if (e->bitmap || prev->bitmap) + goto next; + if (prev->offset + prev->bytes == e->offset) { + unlink_free_space(ctl, prev); + unlink_free_space(ctl, e); + prev->bytes += e->bytes; + kmem_cache_free(btrfs_free_space_cachep, e); + link_free_space(ctl, prev); + prev = NULL; + spin_unlock(&ctl->tree_lock); + goto again; + } +next: + prev = e; + } + spin_unlock(&ctl->tree_lock); +} + +static 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 btrfs_io_ctl io_ctl; + struct btrfs_key key; + struct btrfs_free_space *e, *n; + LIST_HEAD(bitmaps); + u64 num_entries; + u64 num_bitmaps; + u64 generation; + u8 type; + int ret = 0; + + /* Nothing in the space cache, goodbye */ + if (!i_size_read(inode)) + return 0; + + 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 0; + else if (ret > 0) { + btrfs_release_path(path); + return 0; + } + + 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) { + btrfs_info(root->fs_info, + "The free space cache file (%llu) is invalid. skip it\n", + offset); + return 0; + } + + if (BTRFS_I(inode)->generation != generation) { + btrfs_err(root->fs_info, + "free space inode generation (%llu) " + "did not match free space cache generation (%llu)", + BTRFS_I(inode)->generation, generation); + return 0; + } + + if (!num_entries) + return 0; + + ret = io_ctl_init(&io_ctl, inode, root, 0); + if (ret) + return ret; + + ret = readahead_cache(inode); + if (ret) + goto out; + + ret = io_ctl_prepare_pages(&io_ctl, inode, 1); + if (ret) + goto out; + + ret = io_ctl_check_crc(&io_ctl, 0); + if (ret) + goto free_cache; + + ret = io_ctl_check_generation(&io_ctl, generation); + if (ret) + goto free_cache; + + while (num_entries) { + e = kmem_cache_zalloc(btrfs_free_space_cachep, + GFP_NOFS); + if (!e) + goto free_cache; + + ret = io_ctl_read_entry(&io_ctl, e, &type); + if (ret) { + kmem_cache_free(btrfs_free_space_cachep, e); + goto free_cache; + } + + if (!e->bytes) { + kmem_cache_free(btrfs_free_space_cachep, e); + goto free_cache; + } + + if (type == BTRFS_FREE_SPACE_EXTENT) { + spin_lock(&ctl->tree_lock); + ret = link_free_space(ctl, e); + spin_unlock(&ctl->tree_lock); + if (ret) { + btrfs_err(root->fs_info, + "Duplicate entries in free space cache, dumping"); + kmem_cache_free(btrfs_free_space_cachep, e); + goto free_cache; + } + } else { + ASSERT(num_bitmaps); + num_bitmaps--; + e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS); + if (!e->bitmap) { + kmem_cache_free( + btrfs_free_space_cachep, e); + 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) { + btrfs_err(root->fs_info, + "Duplicate entries in free space cache, dumping"); + kmem_cache_free(btrfs_free_space_cachep, e); + goto free_cache; + } + list_add_tail(&e->list, &bitmaps); + } + + num_entries--; + } + + io_ctl_unmap_page(&io_ctl); + + /* + * We add the bitmaps at the end of the entries in order that + * the bitmap entries are added to the cache. + */ + list_for_each_entry_safe(e, n, &bitmaps, list) { + list_del_init(&e->list); + ret = io_ctl_read_bitmap(&io_ctl, e); + if (ret) + goto free_cache; + } + + io_ctl_drop_pages(&io_ctl); + merge_space_tree(ctl); + ret = 1; +out: + io_ctl_free(&io_ctl); + return ret; +free_cache: + io_ctl_drop_pages(&io_ctl); + __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 = 0; + bool matched; + u64 used = btrfs_block_group_used(&block_group->item); + + /* + * 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; + path->search_commit_root = 1; + path->skip_locking = 1; + + inode = lookup_free_space_inode(root, block_group, path); + if (IS_ERR(inode)) { + btrfs_free_path(path); + return 0; + } + + /* We may have converted the inode and made the cache invalid. */ + spin_lock(&block_group->lock); + if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) { + spin_unlock(&block_group->lock); + btrfs_free_path(path); + goto out; + } + spin_unlock(&block_group->lock); + + 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); + btrfs_warn(fs_info, "block group %llu has wrong amount of free space", + 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; + + btrfs_warn(fs_info, "failed to load free space cache for block group %llu, rebuild it now", + block_group->key.objectid); + } + + iput(inode); + return ret; +} + +static noinline_for_stack +int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl, + struct btrfs_free_space_ctl *ctl, + struct btrfs_block_group_cache *block_group, + int *entries, int *bitmaps, + struct list_head *bitmap_list) +{ + int ret; + struct btrfs_free_cluster *cluster = NULL; + struct btrfs_free_cluster *cluster_locked = NULL; + struct rb_node *node = rb_first(&ctl->free_space_offset); + struct btrfs_trim_range *trim_entry; + + /* 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); + } + + if (!node && cluster) { + cluster_locked = cluster; + spin_lock(&cluster_locked->lock); + node = rb_first(&cluster->root); + cluster = NULL; + } + + /* Write out the extent entries */ + while (node) { + struct btrfs_free_space *e; + + e = rb_entry(node, struct btrfs_free_space, offset_index); + *entries += 1; + + ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes, + e->bitmap); + if (ret) + goto fail; + + if (e->bitmap) { + list_add_tail(&e->list, bitmap_list); + *bitmaps += 1; + } + node = rb_next(node); + if (!node && cluster) { + node = rb_first(&cluster->root); + cluster_locked = cluster; + spin_lock(&cluster_locked->lock); + cluster = NULL; + } + } + if (cluster_locked) { + spin_unlock(&cluster_locked->lock); + cluster_locked = NULL; + } + + /* + * Make sure we don't miss any range that was removed from our rbtree + * because trimming is running. Otherwise after a umount+mount (or crash + * after committing the transaction) we would leak free space and get + * an inconsistent free space cache report from fsck. + */ + list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) { + ret = io_ctl_add_entry(io_ctl, trim_entry->start, + trim_entry->bytes, NULL); + if (ret) + goto fail; + *entries += 1; + } + + return 0; +fail: + if (cluster_locked) + spin_unlock(&cluster_locked->lock); + return -ENOSPC; +} + +static noinline_for_stack int +update_cache_item(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct inode *inode, + struct btrfs_path *path, u64 offset, + int entries, int bitmaps) +{ + struct btrfs_key key; + struct btrfs_free_space_header *header; + struct extent_buffer *leaf; + int ret; + + key.objectid = BTRFS_FREE_SPACE_OBJECTID; + key.offset = offset; + key.type = 0; + + ret = btrfs_search_slot(trans, root, &key, path, 0, 1); + if (ret < 0) { + clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1, + EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL, + GFP_NOFS); + goto fail; + } + leaf = path->nodes[0]; + if (ret > 0) { + struct btrfs_key found_key; + ASSERT(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) { + clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, + inode->i_size - 1, + EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, + NULL, GFP_NOFS); + btrfs_release_path(path); + goto fail; + } + } + + BTRFS_I(inode)->generation = trans->transid; + 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); + + return 0; + +fail: + return -1; +} + +static noinline_for_stack int +write_pinned_extent_entries(struct btrfs_root *root, + struct btrfs_block_group_cache *block_group, + struct btrfs_io_ctl *io_ctl, + int *entries) +{ + u64 start, extent_start, extent_end, len; + struct extent_io_tree *unpin = NULL; + int ret; + + if (!block_group) + return 0; + + /* + * We want to add any pinned extents to our free space cache + * so we don't leak the space + * + * We shouldn't have switched the pinned extents yet so this is the + * right one + */ + unpin = root->fs_info->pinned_extents; + + start = block_group->key.objectid; + + while (start < block_group->key.objectid + block_group->key.offset) { + ret = find_first_extent_bit(unpin, start, + &extent_start, &extent_end, + EXTENT_DIRTY, NULL); + if (ret) + return 0; + + /* This pinned extent is out of our range */ + if (extent_start >= block_group->key.objectid + + block_group->key.offset) + return 0; + + extent_start = max(extent_start, start); + extent_end = min(block_group->key.objectid + + block_group->key.offset, extent_end + 1); + len = extent_end - extent_start; + + *entries += 1; + ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL); + if (ret) + return -ENOSPC; + + start = extent_end; + } + + return 0; +} + +static noinline_for_stack int +write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list) +{ + struct list_head *pos, *n; + int ret; + + /* Write out the bitmaps */ + list_for_each_safe(pos, n, bitmap_list) { + struct btrfs_free_space *entry = + list_entry(pos, struct btrfs_free_space, list); + + ret = io_ctl_add_bitmap(io_ctl, entry->bitmap); + if (ret) + return -ENOSPC; + list_del_init(&entry->list); + } + + return 0; +} + +static int flush_dirty_cache(struct inode *inode) +{ + int ret; + + ret = btrfs_wait_ordered_range(inode, 0, (u64)-1); + if (ret) + clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1, + EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL, + GFP_NOFS); + + return ret; +} + +static void noinline_for_stack +cleanup_bitmap_list(struct list_head *bitmap_list) +{ + struct list_head *pos, *n; + + list_for_each_safe(pos, n, bitmap_list) { + struct btrfs_free_space *entry = + list_entry(pos, struct btrfs_free_space, list); + list_del_init(&entry->list); + } +} + +static void noinline_for_stack +cleanup_write_cache_enospc(struct inode *inode, + struct btrfs_io_ctl *io_ctl, + struct extent_state **cached_state, + struct list_head *bitmap_list) +{ + io_ctl_drop_pages(io_ctl); + unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0, + i_size_read(inode) - 1, cached_state, + GFP_NOFS); +} + +int btrfs_wait_cache_io(struct btrfs_root *root, + struct btrfs_trans_handle *trans, + struct btrfs_block_group_cache *block_group, + struct btrfs_io_ctl *io_ctl, + struct btrfs_path *path, u64 offset) +{ + int ret; + struct inode *inode = io_ctl->inode; + + if (!inode) + return 0; + + if (block_group) + root = root->fs_info->tree_root; + + /* Flush the dirty pages in the cache file. */ + ret = flush_dirty_cache(inode); + if (ret) + goto out; + + /* Update the cache item to tell everyone this cache file is valid. */ + ret = update_cache_item(trans, root, inode, path, offset, + io_ctl->entries, io_ctl->bitmaps); +out: + io_ctl_free(io_ctl); + if (ret) { + invalidate_inode_pages2(inode->i_mapping); + BTRFS_I(inode)->generation = 0; + if (block_group) { +#ifdef DEBUG + btrfs_err(root->fs_info, + "failed to write free space cache for block group %llu", + block_group->key.objectid); +#endif + } + } + btrfs_update_inode(trans, root, inode); + + if (block_group) { + /* the dirty list is protected by the dirty_bgs_lock */ + spin_lock(&trans->transaction->dirty_bgs_lock); + + /* the disk_cache_state is protected by the block group lock */ + spin_lock(&block_group->lock); + + /* + * only mark this as written if we didn't get put back on + * the dirty list while waiting for IO. Otherwise our + * cache state won't be right, and we won't get written again + */ + if (!ret && list_empty(&block_group->dirty_list)) + block_group->disk_cache_state = BTRFS_DC_WRITTEN; + else if (ret) + block_group->disk_cache_state = BTRFS_DC_ERROR; + + spin_unlock(&block_group->lock); + spin_unlock(&trans->transaction->dirty_bgs_lock); + io_ctl->inode = NULL; + iput(inode); + } + + return ret; + +} + +/** + * __btrfs_write_out_cache - write out cached info to an inode + * @root - the root the inode belongs to + * @ctl - the free space cache we are going to write out + * @block_group - the block_group for this cache if it belongs to a block_group + * @trans - the trans handle + * @path - the path to use + * @offset - the offset for the key we'll insert + * + * This function writes out a free space cache struct to disk for quick recovery + * on mount. This will return 0 if it was successfull in writing the cache out, + * or an errno if it was not. + */ +static 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_io_ctl *io_ctl, + struct btrfs_trans_handle *trans, + struct btrfs_path *path, u64 offset) +{ + struct extent_state *cached_state = NULL; + LIST_HEAD(bitmap_list); + int entries = 0; + int bitmaps = 0; + int ret; + int must_iput = 0; + + if (!i_size_read(inode)) + return -EIO; + + WARN_ON(io_ctl->pages); + ret = io_ctl_init(io_ctl, inode, root, 1); + if (ret) + return ret; + + if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) { + down_write(&block_group->data_rwsem); + spin_lock(&block_group->lock); + if (block_group->delalloc_bytes) { + block_group->disk_cache_state = BTRFS_DC_WRITTEN; + spin_unlock(&block_group->lock); + up_write(&block_group->data_rwsem); + BTRFS_I(inode)->generation = 0; + ret = 0; + must_iput = 1; + goto out; + } + spin_unlock(&block_group->lock); + } + + /* Lock all pages first so we can lock the extent safely. */ + ret = io_ctl_prepare_pages(io_ctl, inode, 0); + if (ret) + goto out; + + lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1, + 0, &cached_state); + + io_ctl_set_generation(io_ctl, trans->transid); + + mutex_lock(&ctl->cache_writeout_mutex); + /* Write out the extent entries in the free space cache */ + spin_lock(&ctl->tree_lock); + ret = write_cache_extent_entries(io_ctl, ctl, + block_group, &entries, &bitmaps, + &bitmap_list); + if (ret) + goto out_nospc_locked; + + /* + * Some spaces that are freed in the current transaction are pinned, + * they will be added into free space cache after the transaction is + * committed, we shouldn't lose them. + * + * If this changes while we are working we'll get added back to + * the dirty list and redo it. No locking needed + */ + ret = write_pinned_extent_entries(root, block_group, io_ctl, &entries); + if (ret) + goto out_nospc_locked; + + /* + * At last, we write out all the bitmaps and keep cache_writeout_mutex + * locked while doing it because a concurrent trim can be manipulating + * or freeing the bitmap. + */ + ret = write_bitmap_entries(io_ctl, &bitmap_list); + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + if (ret) + goto out_nospc; + + /* Zero out the rest of the pages just to make sure */ + io_ctl_zero_remaining_pages(io_ctl); + + /* Everything is written out, now we dirty the pages in the file. */ + ret = btrfs_dirty_pages(root, inode, io_ctl->pages, io_ctl->num_pages, + 0, i_size_read(inode), &cached_state); + if (ret) + goto out_nospc; + + if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) + up_write(&block_group->data_rwsem); + /* + * Release the pages and unlock the extent, we will flush + * them out later + */ + io_ctl_drop_pages(io_ctl); + + unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0, + i_size_read(inode) - 1, &cached_state, GFP_NOFS); + + /* + * at this point the pages are under IO and we're happy, + * The caller is responsible for waiting on them and updating the + * the cache and the inode + */ + io_ctl->entries = entries; + io_ctl->bitmaps = bitmaps; + + ret = btrfs_fdatawrite_range(inode, 0, (u64)-1); + if (ret) + goto out; + + return 0; + +out: + io_ctl->inode = NULL; + io_ctl_free(io_ctl); + if (ret) { + invalidate_inode_pages2(inode->i_mapping); + BTRFS_I(inode)->generation = 0; + } + btrfs_update_inode(trans, root, inode); + if (must_iput) + iput(inode); + return ret; + +out_nospc_locked: + cleanup_bitmap_list(&bitmap_list); + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + +out_nospc: + cleanup_write_cache_enospc(inode, io_ctl, &cached_state, &bitmap_list); + + if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) + up_write(&block_group->data_rwsem); + + goto out; +} + +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, + &block_group->io_ctl, trans, + path, block_group->key.objectid); + if (ret) { +#ifdef DEBUG + btrfs_err(root->fs_info, + "failed to write free space cache for block group %llu", + block_group->key.objectid); +#endif + spin_lock(&block_group->lock); + block_group->disk_cache_state = BTRFS_DC_ERROR; + spin_unlock(&block_group->lock); + + block_group->io_ctl.inode = NULL; + iput(inode); + } + + /* + * if ret == 0 the caller is expected to call btrfs_wait_cache_io + * to wait for IO and put the inode + */ + + return ret; +} + +static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit, + u64 offset) +{ + ASSERT(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; + u32 bytes_per_bitmap; + + bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit; + bitmap_start = offset - ctl->start; + bitmap_start = div_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 = rb_prev(&entry->offset_index); + if (n) { + prev = rb_entry(n, struct btrfs_free_space, + offset_index); + if (!prev->bitmap && + prev->offset + prev->bytes > offset) + entry = prev; + } + } + 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); + ASSERT(entry->offset <= offset); + } else { + if (fuzzy) + return entry; + else + return NULL; + } + } + + if (entry->bitmap) { + n = rb_prev(&entry->offset_index); + if (n) { + prev = rb_entry(n, struct btrfs_free_space, + offset_index); + if (!prev->bitmap && + prev->offset + prev->bytes > offset) + return prev; + } + 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; + + ASSERT(info->bytes || info->bitmap); + 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; + u32 bytes_per_bg = BITS_PER_BITMAP * ctl->unit; + u32 max_bitmaps = div_u64(size + bytes_per_bg - 1, bytes_per_bg); + + max_bitmaps = max_t(u32, max_bitmaps, 1); + + ASSERT(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 * + div_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 max + * bytes we can have, or whatever is less than that. + */ + extent_bytes = max_bytes - bitmap_bytes; + extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1); + + ctl->extents_thresh = + div_u64(extent_bytes, sizeof(struct btrfs_free_space)); +} + +static inline 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); + ASSERT(start + count <= BITS_PER_BITMAP); + + bitmap_clear(info->bitmap, start, count); + + info->bytes -= bytes; +} + +static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, u64 offset, + u64 bytes) +{ + __bitmap_clear_bits(ctl, info, offset, 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); + ASSERT(start + count <= BITS_PER_BITMAP); + + bitmap_set(info->bitmap, start, count); + + info->bytes += bytes; + ctl->free_space += bytes; +} + +/* + * If we can not find suitable extent, we will use bytes to record + * the size of the max extent. + */ +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 max_bits = 0; + unsigned long bits, i; + unsigned long next_zero; + unsigned long extent_bits; + + i = offset_to_bit(bitmap_info->offset, ctl->unit, + max_t(u64, *offset, bitmap_info->offset)); + bits = bytes_to_bits(*bytes, ctl->unit); + + for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) { + next_zero = find_next_zero_bit(bitmap_info->bitmap, + BITS_PER_BITMAP, i); + extent_bits = next_zero - i; + if (extent_bits >= bits) { + found_bits = extent_bits; + break; + } else if (extent_bits > max_bits) { + max_bits = extent_bits; + } + i = next_zero; + } + + if (found_bits) { + *offset = (u64)(i * ctl->unit) + bitmap_info->offset; + *bytes = (u64)(found_bits) * ctl->unit; + return 0; + } + + *bytes = (u64)(max_bits) * ctl->unit; + return -1; +} + +/* Cache the size of the max extent in bytes */ +static struct btrfs_free_space * +find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes, + unsigned long align, u64 *max_extent_size) +{ + struct btrfs_free_space *entry; + struct rb_node *node; + u64 tmp; + u64 align_off; + int ret; + + if (!ctl->free_space_offset.rb_node) + goto out; + + entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1); + if (!entry) + goto out; + + for (node = &entry->offset_index; node; node = rb_next(node)) { + entry = rb_entry(node, struct btrfs_free_space, offset_index); + if (entry->bytes < *bytes) { + if (entry->bytes > *max_extent_size) + *max_extent_size = entry->bytes; + continue; + } + + /* make sure the space returned is big enough + * to match our requested alignment + */ + if (*bytes >= align) { + tmp = entry->offset - ctl->start + align - 1; + tmp = div64_u64(tmp, align); + tmp = tmp * align + ctl->start; + align_off = tmp - entry->offset; + } else { + align_off = 0; + tmp = entry->offset; + } + + if (entry->bytes < *bytes + align_off) { + if (entry->bytes > *max_extent_size) + *max_extent_size = entry->bytes; + continue; + } + + if (entry->bitmap) { + u64 size = *bytes; + + ret = search_bitmap(ctl, entry, &tmp, &size); + if (!ret) { + *offset = tmp; + *bytes = size; + return entry; + } else if (size > *max_extent_size) { + *max_extent_size = size; + } + continue; + } + + *offset = tmp; + *bytes = entry->bytes - align_off; + return entry; + } +out: + 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; + INIT_LIST_HEAD(&info->list); + 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; + + /* + * We need to search for bits in this bitmap. We could only cover some + * of the extent in this bitmap thanks to how we add space, so we need + * to search for as much as it as we can and clear that amount, and then + * go searching for the next bit. + */ + search_start = *offset; + search_bytes = ctl->unit; + search_bytes = min(search_bytes, end - search_start + 1); + ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes); + if (ret < 0 || search_start != *offset) + return -EINVAL; + + /* We may have found more bits than what we need */ + search_bytes = min(search_bytes, *bytes); + + /* Cannot clear past the end of the bitmap */ + search_bytes = min(search_bytes, end - search_start + 1); + + bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes); + *offset += search_bytes; + *bytes -= search_bytes; + + 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 = ctl->unit; + 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; + } + } + + /* + * The original block groups from mkfs can be really small, like 8 + * megabytes, so don't bother with a bitmap for those entries. However + * some block groups can be smaller than what a bitmap would cover but + * are still large enough that they could overflow the 32k memory limit, + * so allow those block groups to still be allowed to have a bitmap + * entry. + */ + if (((BITS_PER_BITMAP * ctl->unit) >> 1) > 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) { + ASSERT(added == 0); + 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; +} + +static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, + bool update_stat) +{ + struct btrfs_free_space *bitmap; + unsigned long i; + unsigned long j; + const u64 end = info->offset + info->bytes; + const u64 bitmap_offset = offset_to_bitmap(ctl, end); + u64 bytes; + + bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0); + if (!bitmap) + return false; + + i = offset_to_bit(bitmap->offset, ctl->unit, end); + j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i); + if (j == i) + return false; + bytes = (j - i) * ctl->unit; + info->bytes += bytes; + + if (update_stat) + bitmap_clear_bits(ctl, bitmap, end, bytes); + else + __bitmap_clear_bits(ctl, bitmap, end, bytes); + + if (!bitmap->bytes) + free_bitmap(ctl, bitmap); + + return true; +} + +static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, + bool update_stat) +{ + struct btrfs_free_space *bitmap; + u64 bitmap_offset; + unsigned long i; + unsigned long j; + unsigned long prev_j; + u64 bytes; + + bitmap_offset = offset_to_bitmap(ctl, info->offset); + /* If we're on a boundary, try the previous logical bitmap. */ + if (bitmap_offset == info->offset) { + if (info->offset == 0) + return false; + bitmap_offset = offset_to_bitmap(ctl, info->offset - 1); + } + + bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0); + if (!bitmap) + return false; + + i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1; + j = 0; + prev_j = (unsigned long)-1; + for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) { + if (j > i) + break; + prev_j = j; + } + if (prev_j == i) + return false; + + if (prev_j == (unsigned long)-1) + bytes = (i + 1) * ctl->unit; + else + bytes = (i - prev_j) * ctl->unit; + + info->offset -= bytes; + info->bytes += bytes; + + if (update_stat) + bitmap_clear_bits(ctl, bitmap, info->offset, bytes); + else + __bitmap_clear_bits(ctl, bitmap, info->offset, bytes); + + if (!bitmap->bytes) + free_bitmap(ctl, bitmap); + + return true; +} + +/* + * We prefer always to allocate from extent entries, both for clustered and + * non-clustered allocation requests. So when attempting to add a new extent + * entry, try to see if there's adjacent free space in bitmap entries, and if + * there is, migrate that space from the bitmaps to the extent. + * Like this we get better chances of satisfying space allocation requests + * because we attempt to satisfy them based on a single cache entry, and never + * on 2 or more entries - even if the entries represent a contiguous free space + * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry + * ends). + */ +static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl, + struct btrfs_free_space *info, + bool update_stat) +{ + /* + * Only work with disconnected entries, as we can change their offset, + * and must be extent entries. + */ + ASSERT(!info->bitmap); + ASSERT(RB_EMPTY_NODE(&info->offset_index)); + + if (ctl->total_bitmaps > 0) { + bool stole_end; + bool stole_front = false; + + stole_end = steal_from_bitmap_to_end(ctl, info, update_stat); + if (ctl->total_bitmaps > 0) + stole_front = steal_from_bitmap_to_front(ctl, info, + update_stat); + + if (stole_end || stole_front) + try_merge_free_space(ctl, info, update_stat); + } +} + +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; + RB_CLEAR_NODE(&info->offset_index); + + 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: + /* + * Only steal free space from adjacent bitmaps if we're sure we're not + * going to add the new free space to existing bitmap entries - because + * that would mean unnecessary work that would be reverted. Therefore + * attempt to steal space from bitmaps if we're adding an extent entry. + */ + steal_from_bitmap(ctl, info, true); + + 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); + ASSERT(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; + int ret; + bool re_search = false; + + spin_lock(&ctl->tree_lock); + +again: + ret = 0; + if (!bytes) + goto out_lock; + + 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) { + /* + * If we found a partial bit of our free space in a + * bitmap but then couldn't find the other part this may + * be a problem, so WARN about it. + */ + WARN_ON(re_search); + goto out_lock; + } + } + + re_search = false; + if (!info->bitmap) { + unlink_free_space(ctl, info); + if (offset == info->offset) { + u64 to_free = min(bytes, info->bytes); + + info->bytes -= to_free; + info->offset += to_free; + if (info->bytes) { + ret = link_free_space(ctl, info); + WARN_ON(ret); + } else { + kmem_cache_free(btrfs_free_space_cachep, info); + } + + offset += to_free; + bytes -= to_free; + goto again; + } else { + u64 old_end = info->bytes + info->offset; + + info->bytes = offset - info->offset; + ret = link_free_space(ctl, info); + WARN_ON(ret); + if (ret) + goto out_lock; + + /* Not enough bytes in this entry to satisfy us */ + if (old_end < offset + bytes) { + bytes -= old_end - offset; + offset = old_end; + goto again; + } else if (old_end == offset + bytes) { + /* all done */ + goto out_lock; + } + spin_unlock(&ctl->tree_lock); + + ret = btrfs_add_free_space(block_group, offset + bytes, + old_end - (offset + bytes)); + WARN_ON(ret); + goto out; + } + } + + ret = remove_from_bitmap(ctl, info, &offset, &bytes); + if (ret == -EAGAIN) { + re_search = true; + goto again; + } +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 && !block_group->ro) + count++; + btrfs_crit(block_group->fs_info, + "entry offset %llu, bytes %llu, bitmap %s", + info->offset, info->bytes, + (info->bitmap) ? "yes" : "no"); + } + btrfs_info(block_group->fs_info, "block group has cluster?: %s", + list_empty(&block_group->cluster_list) ? "no" : "yes"); + btrfs_info(block_group->fs_info, + "%d blocks of free space at or bigger than bytes is", 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; + INIT_LIST_HEAD(&ctl->trimming_ranges); + mutex_init(&ctl->cache_writeout_mutex); + + /* + * 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); + RB_CLEAR_NODE(&entry->offset_index); + + bitmap = (entry->bitmap != NULL); + if (!bitmap) { + try_merge_free_space(ctl, entry, false); + steal_from_bitmap(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; +} + +static 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); + if (!info->bitmap) { + unlink_free_space(ctl, info); + kmem_cache_free(btrfs_free_space_cachep, info); + } else { + free_bitmap(ctl, info); + } + + cond_resched_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); + + cond_resched_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, + u64 *max_extent_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; + u64 align_gap = 0; + u64 align_gap_len = 0; + + spin_lock(&ctl->tree_lock); + entry = find_free_space(ctl, &offset, &bytes_search, + block_group->full_stripe_len, max_extent_size); + 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); + align_gap_len = offset - entry->offset; + align_gap = entry->offset; + + entry->offset = offset + bytes; + WARN_ON(entry->bytes < bytes + align_gap_len); + + entry->bytes -= bytes + align_gap_len; + if (!entry->bytes) + kmem_cache_free(btrfs_free_space_cachep, entry); + else + link_free_space(ctl, entry); + } +out: + spin_unlock(&ctl->tree_lock); + + if (align_gap_len) + __btrfs_add_free_space(ctl, align_gap, align_gap_len); + 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, + u64 *max_extent_size) +{ + 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) { + if (search_bytes > *max_extent_size) + *max_extent_size = search_bytes; + 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, u64 *max_extent_size) +{ + 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->bytes > *max_extent_size) + *max_extent_size = entry->bytes; + + 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, + cluster->window_start, + max_extent_size); + if (ret == 0) { + node = rb_next(&entry->offset_index); + if (!node) + break; + entry = rb_entry(node, struct btrfs_free_space, + offset_index); + continue; + } + cluster->window_start += bytes; + } 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 cont1_bytes, u64 min_bytes) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + unsigned long next_zero; + unsigned long i; + unsigned long want_bits; + unsigned long min_bits; + unsigned long found_bits; + unsigned long start = 0; + unsigned long total_found = 0; + int ret; + + i = offset_to_bit(entry->offset, ctl->unit, + max_t(u64, offset, entry->offset)); + want_bits = bytes_to_bits(bytes, ctl->unit); + min_bits = bytes_to_bits(min_bytes, ctl->unit); + +again: + found_bits = 0; + for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) { + next_zero = find_next_zero_bit(entry->bitmap, + BITS_PER_BITMAP, i); + if (next_zero - i >= min_bits) { + found_bits = next_zero - i; + break; + } + i = next_zero; + } + + if (!found_bits) + return -ENOSPC; + + if (!total_found) { + start = i; + cluster->max_size = 0; + } + + total_found += found_bits; + + if (cluster->max_size < found_bits * ctl->unit) + cluster->max_size = found_bits * ctl->unit; + + if (total_found < want_bits || cluster->max_size < cont1_bytes) { + i = next_zero + 1; + goto again; + } + + cluster->window_start = start * ctl->unit + entry->offset; + rb_erase(&entry->offset_index, &ctl->free_space_offset); + ret = tree_insert_offset(&cluster->root, entry->offset, + &entry->offset_index, 1); + ASSERT(!ret); /* -EEXIST; Logic error */ + + trace_btrfs_setup_cluster(block_group, cluster, + total_found * ctl->unit, 1); + return 0; +} + +/* + * This searches the block group for just extents to fill the cluster with. + * Try to find a cluster with at least bytes total bytes, at least one + * extent of cont1_bytes, and other clusters of at least min_bytes. + */ +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 cont1_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 *last; + struct rb_node *node; + u64 window_free; + u64 max_extent; + u64 total_size = 0; + + 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 || entry->bytes < min_bytes) { + if (entry->bitmap && 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_free = entry->bytes; + max_extent = entry->bytes; + first = entry; + last = entry; + + for (node = rb_next(&entry->offset_index); node; + node = rb_next(&entry->offset_index)) { + 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; + } + + if (entry->bytes < min_bytes) + continue; + + last = entry; + window_free += entry->bytes; + if (entry->bytes > max_extent) + max_extent = entry->bytes; + } + + if (window_free < bytes || max_extent < cont1_bytes) + return -ENOSPC; + + 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 || entry->bytes < min_bytes) + continue; + + rb_erase(&entry->offset_index, &ctl->free_space_offset); + ret = tree_insert_offset(&cluster->root, entry->offset, + &entry->offset_index, 0); + total_size += entry->bytes; + ASSERT(!ret); /* -EEXIST; Logic error */ + } while (node && entry != last); + + cluster->max_size = max_extent; + trace_btrfs_setup_cluster(block_group, cluster, total_size, 0); + 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 cont1_bytes, u64 min_bytes) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space *entry; + int ret = -ENOSPC; + u64 bitmap_offset = offset_to_bitmap(ctl, offset); + + if (ctl->total_bitmaps == 0) + return -ENOSPC; + + /* + * The bitmap that covers offset won't be in the list unless offset + * is just its start offset. + */ + entry = list_first_entry(bitmaps, struct btrfs_free_space, list); + if (entry->offset != bitmap_offset) { + entry = tree_search_offset(ctl, bitmap_offset, 1, 0); + if (entry && list_empty(&entry->list)) + list_add(&entry->list, bitmaps); + } + + list_for_each_entry(entry, bitmaps, list) { + if (entry->bytes < bytes) + continue; + ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset, + bytes, cont1_bytes, min_bytes); + if (!ret) + return 0; + } + + /* + * The bitmaps list has all the bitmaps that record free space + * starting after offset, so no more search is required. + */ + return -ENOSPC; +} + +/* + * here we try to find a cluster of blocks in a block group. The goal + * is to find at least bytes+empty_size. + * 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_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 btrfs_free_space *entry, *tmp; + LIST_HEAD(bitmaps); + u64 min_bytes; + u64 cont1_bytes; + int ret; + + /* + * Choose the minimum extent size we'll require for this + * cluster. For SSD_SPREAD, don't allow any fragmentation. + * For metadata, allow allocates with smaller extents. For + * data, keep it dense. + */ + if (btrfs_test_opt(root, SSD_SPREAD)) { + cont1_bytes = min_bytes = bytes + empty_size; + } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) { + cont1_bytes = bytes; + min_bytes = block_group->sectorsize; + } else { + cont1_bytes = max(bytes, (bytes + empty_size) >> 2); + min_bytes = block_group->sectorsize; + } + + 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 < 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; + } + + trace_btrfs_find_cluster(block_group, offset, bytes, empty_size, + min_bytes); + + ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset, + bytes + empty_size, + cont1_bytes, min_bytes); + if (ret) + ret = setup_cluster_bitmap(block_group, cluster, &bitmaps, + offset, bytes + empty_size, + cont1_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; + } else { + trace_btrfs_failed_cluster_setup(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; +} + +static int do_trimming(struct btrfs_block_group_cache *block_group, + u64 *total_trimmed, u64 start, u64 bytes, + u64 reserved_start, u64 reserved_bytes, + struct btrfs_trim_range *trim_entry) +{ + struct btrfs_space_info *space_info = block_group->space_info; + struct btrfs_fs_info *fs_info = block_group->fs_info; + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + int ret; + int update = 0; + u64 trimmed = 0; + + spin_lock(&space_info->lock); + spin_lock(&block_group->lock); + if (!block_group->ro) { + block_group->reserved += reserved_bytes; + space_info->bytes_reserved += reserved_bytes; + update = 1; + } + spin_unlock(&block_group->lock); + spin_unlock(&space_info->lock); + + ret = btrfs_discard_extent(fs_info->extent_root, + start, bytes, &trimmed); + if (!ret) + *total_trimmed += trimmed; + + mutex_lock(&ctl->cache_writeout_mutex); + btrfs_add_free_space(block_group, reserved_start, reserved_bytes); + list_del(&trim_entry->list); + mutex_unlock(&ctl->cache_writeout_mutex); + + if (update) { + spin_lock(&space_info->lock); + spin_lock(&block_group->lock); + if (block_group->ro) + space_info->bytes_readonly += reserved_bytes; + block_group->reserved -= reserved_bytes; + space_info->bytes_reserved -= reserved_bytes; + spin_unlock(&space_info->lock); + spin_unlock(&block_group->lock); + } + + return ret; +} + +static int trim_no_bitmap(struct btrfs_block_group_cache *block_group, + u64 *total_trimmed, u64 start, u64 end, u64 minlen) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space *entry; + struct rb_node *node; + int ret = 0; + u64 extent_start; + u64 extent_bytes; + u64 bytes; + + while (start < end) { + struct btrfs_trim_range trim_entry; + + mutex_lock(&ctl->cache_writeout_mutex); + spin_lock(&ctl->tree_lock); + + if (ctl->free_space < minlen) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + break; + } + + entry = tree_search_offset(ctl, start, 0, 1); + if (!entry) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + break; + } + + /* skip bitmaps */ + while (entry->bitmap) { + node = rb_next(&entry->offset_index); + if (!node) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + goto out; + } + entry = rb_entry(node, struct btrfs_free_space, + offset_index); + } + + if (entry->offset >= end) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + break; + } + + extent_start = entry->offset; + extent_bytes = entry->bytes; + start = max(start, extent_start); + bytes = min(extent_start + extent_bytes, end) - start; + if (bytes < minlen) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + goto next; + } + + unlink_free_space(ctl, entry); + kmem_cache_free(btrfs_free_space_cachep, entry); + + spin_unlock(&ctl->tree_lock); + trim_entry.start = extent_start; + trim_entry.bytes = extent_bytes; + list_add_tail(&trim_entry.list, &ctl->trimming_ranges); + mutex_unlock(&ctl->cache_writeout_mutex); + + ret = do_trimming(block_group, total_trimmed, start, bytes, + extent_start, extent_bytes, &trim_entry); + if (ret) + break; +next: + start += bytes; + + if (fatal_signal_pending(current)) { + ret = -ERESTARTSYS; + break; + } + + cond_resched(); + } +out: + return ret; +} + +static int trim_bitmaps(struct btrfs_block_group_cache *block_group, + u64 *total_trimmed, u64 start, u64 end, u64 minlen) +{ + struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; + struct btrfs_free_space *entry; + int ret = 0; + int ret2; + u64 bytes; + u64 offset = offset_to_bitmap(ctl, start); + + while (offset < end) { + bool next_bitmap = false; + struct btrfs_trim_range trim_entry; + + mutex_lock(&ctl->cache_writeout_mutex); + spin_lock(&ctl->tree_lock); + + if (ctl->free_space < minlen) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + break; + } + + entry = tree_search_offset(ctl, offset, 1, 0); + if (!entry) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + next_bitmap = true; + goto next; + } + + bytes = minlen; + ret2 = search_bitmap(ctl, entry, &start, &bytes); + if (ret2 || start >= end) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + next_bitmap = true; + goto next; + } + + bytes = min(bytes, end - start); + if (bytes < minlen) { + spin_unlock(&ctl->tree_lock); + mutex_unlock(&ctl->cache_writeout_mutex); + goto next; + } + + bitmap_clear_bits(ctl, entry, start, bytes); + if (entry->bytes == 0) + free_bitmap(ctl, entry); + + spin_unlock(&ctl->tree_lock); + trim_entry.start = start; + trim_entry.bytes = bytes; + list_add_tail(&trim_entry.list, &ctl->trimming_ranges); + mutex_unlock(&ctl->cache_writeout_mutex); + + ret = do_trimming(block_group, total_trimmed, start, bytes, + start, bytes, &trim_entry); + if (ret) + break; +next: + if (next_bitmap) { + offset += BITS_PER_BITMAP * ctl->unit; + } else { + start += bytes; + if (start >= offset + BITS_PER_BITMAP * ctl->unit) + offset += BITS_PER_BITMAP * ctl->unit; + } + + if (fatal_signal_pending(current)) { + ret = -ERESTARTSYS; + break; + } + + cond_resched(); + } + + return ret; +} + +int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group, + u64 *trimmed, u64 start, u64 end, u64 minlen) +{ + int ret; + + *trimmed = 0; + + spin_lock(&block_group->lock); + if (block_group->removed) { + spin_unlock(&block_group->lock); + return 0; + } + atomic_inc(&block_group->trimming); + spin_unlock(&block_group->lock); + + ret = trim_no_bitmap(block_group, trimmed, start, end, minlen); + if (ret) + goto out; + + ret = trim_bitmaps(block_group, trimmed, start, end, minlen); +out: + spin_lock(&block_group->lock); + if (atomic_dec_and_test(&block_group->trimming) && + block_group->removed) { + struct extent_map_tree *em_tree; + struct extent_map *em; + + spin_unlock(&block_group->lock); + + lock_chunks(block_group->fs_info->chunk_root); + em_tree = &block_group->fs_info->mapping_tree.map_tree; + write_lock(&em_tree->lock); + em = lookup_extent_mapping(em_tree, block_group->key.objectid, + 1); + BUG_ON(!em); /* logic error, can't happen */ + /* + * remove_extent_mapping() will delete us from the pinned_chunks + * list, which is protected by the chunk mutex. + */ + remove_extent_mapping(em_tree, em); + write_unlock(&em_tree->lock); + unlock_chunks(block_group->fs_info->chunk_root); + + /* once for us and once for the tree */ + free_extent_map(em); + free_extent_map(em); + + /* + * We've left one free space entry and other tasks trimming + * this block group have left 1 entry each one. Free them. + */ + __btrfs_remove_free_space_cache(block_group->free_space_ctl); + } else { + spin_unlock(&block_group->lock); + } + + 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); + /* Logic error; Should be empty if it can't find anything */ + ASSERT(!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->ino_cache_lock); + if (root->ino_cache_inode) + inode = igrab(root->ino_cache_inode); + spin_unlock(&root->ino_cache_lock); + if (inode) + return inode; + + inode = __lookup_free_space_inode(root, path, 0); + if (IS_ERR(inode)) + return inode; + + spin_lock(&root->ino_cache_lock); + if (!btrfs_fs_closing(root->fs_info)) + root->ino_cache_inode = igrab(inode); + spin_unlock(&root->ino_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) + btrfs_err(fs_info, + "failed to load free ino cache for root %llu", + 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 inode *inode) +{ + struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; + int ret; + struct btrfs_io_ctl io_ctl; + bool release_metadata = true; + + if (!btrfs_test_opt(root, INODE_MAP_CACHE)) + return 0; + + memset(&io_ctl, 0, sizeof(io_ctl)); + ret = __btrfs_write_out_cache(root, inode, ctl, NULL, &io_ctl, + trans, path, 0); + if (!ret) { + /* + * At this point writepages() didn't error out, so our metadata + * reservation is released when the writeback finishes, at + * inode.c:btrfs_finish_ordered_io(), regardless of it finishing + * with or without an error. + */ + release_metadata = false; + ret = btrfs_wait_cache_io(root, trans, NULL, &io_ctl, path, 0); + } + + if (ret) { + if (release_metadata) + btrfs_delalloc_release_metadata(inode, inode->i_size); +#ifdef DEBUG + btrfs_err(root->fs_info, + "failed to write free ino cache for root %llu", + root->root_key.objectid); +#endif + } + + return ret; +} + +#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS +/* + * Use this if you need to make a bitmap or extent entry specifically, it + * doesn't do any of the merging that add_free_space does, this acts a lot like + * how the free space cache loading stuff works, so you can get really weird + * configurations. + */ +int test_add_free_space_entry(struct btrfs_block_group_cache *cache, + u64 offset, u64 bytes, bool bitmap) +{ + struct btrfs_free_space_ctl *ctl = cache->free_space_ctl; + struct btrfs_free_space *info = NULL, *bitmap_info; + void *map = NULL; + u64 bytes_added; + int ret; + +again: + if (!info) { + info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS); + if (!info) + return -ENOMEM; + } + + if (!bitmap) { + spin_lock(&ctl->tree_lock); + info->offset = offset; + info->bytes = bytes; + ret = link_free_space(ctl, info); + spin_unlock(&ctl->tree_lock); + if (ret) + kmem_cache_free(btrfs_free_space_cachep, info); + return ret; + } + + if (!map) { + map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS); + if (!map) { + kmem_cache_free(btrfs_free_space_cachep, info); + return -ENOMEM; + } + } + + spin_lock(&ctl->tree_lock); + bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), + 1, 0); + if (!bitmap_info) { + info->bitmap = map; + map = NULL; + add_new_bitmap(ctl, info, offset); + bitmap_info = info; + info = NULL; + } + + bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes); + bytes -= bytes_added; + offset += bytes_added; + spin_unlock(&ctl->tree_lock); + + if (bytes) + goto again; + + if (info) + kmem_cache_free(btrfs_free_space_cachep, info); + if (map) + kfree(map); + return 0; +} + +/* + * Checks to see if the given range is in the free space cache. This is really + * just used to check the absence of space, so if there is free space in the + * range at all we will return 1. + */ +int test_check_exists(struct btrfs_block_group_cache *cache, + u64 offset, u64 bytes) +{ + struct btrfs_free_space_ctl *ctl = cache->free_space_ctl; + struct btrfs_free_space *info; + int ret = 0; + + spin_lock(&ctl->tree_lock); + info = tree_search_offset(ctl, offset, 0, 0); + if (!info) { + info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), + 1, 0); + if (!info) + goto out; + } + +have_info: + if (info->bitmap) { + u64 bit_off, bit_bytes; + struct rb_node *n; + struct btrfs_free_space *tmp; + + bit_off = offset; + bit_bytes = ctl->unit; + ret = search_bitmap(ctl, info, &bit_off, &bit_bytes); + if (!ret) { + if (bit_off == offset) { + ret = 1; + goto out; + } else if (bit_off > offset && + offset + bytes > bit_off) { + ret = 1; + goto out; + } + } + + n = rb_prev(&info->offset_index); + while (n) { + tmp = rb_entry(n, struct btrfs_free_space, + offset_index); + if (tmp->offset + tmp->bytes < offset) + break; + if (offset + bytes < tmp->offset) { + n = rb_prev(&info->offset_index); + continue; + } + info = tmp; + goto have_info; + } + + n = rb_next(&info->offset_index); + while (n) { + tmp = rb_entry(n, struct btrfs_free_space, + offset_index); + if (offset + bytes < tmp->offset) + break; + if (tmp->offset + tmp->bytes < offset) { + n = rb_next(&info->offset_index); + continue; + } + info = tmp; + goto have_info; + } + + ret = 0; + goto out; + } + + if (info->offset == offset) { + ret = 1; + goto out; + } + + if (offset > info->offset && offset < info->offset + info->bytes) + ret = 1; +out: + spin_unlock(&ctl->tree_lock); + return ret; +} +#endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */ |