diff options
Diffstat (limited to 'fs/btrfs/free-space-cache.c')
| -rw-r--r-- | fs/btrfs/free-space-cache.c | 751 |
1 files changed, 751 insertions, 0 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index f488fac04d9..22ee0dc2e6b 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -23,10 +23,761 @@ #include "ctree.h" #include "free-space-cache.h" #include "transaction.h" +#include "disk-io.h" #define BITS_PER_BITMAP (PAGE_CACHE_SIZE * 8) #define MAX_CACHE_BYTES_PER_GIG (32 * 1024) +static void recalculate_thresholds(struct btrfs_block_group_cache + *block_group); +static int link_free_space(struct btrfs_block_group_cache *block_group, + struct btrfs_free_space *info); + +struct inode *lookup_free_space_inode(struct btrfs_root *root, + struct btrfs_block_group_cache + *block_group, struct btrfs_path *path) +{ + 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; + + spin_lock(&block_group->lock); + if (block_group->inode) + inode = igrab(block_group->inode); + spin_unlock(&block_group->lock); + if (inode) + return inode; + + key.objectid = BTRFS_FREE_SPACE_OBJECTID; + key.offset = block_group->key.objectid; + 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(root, 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(root, 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); + } + + spin_lock(&block_group->lock); + if (!root->fs_info->closing) { + block_group->inode = igrab(inode); + block_group->iref = 1; + } + spin_unlock(&block_group->lock); + + return inode; +} + +int create_free_space_inode(struct btrfs_root *root, + struct btrfs_trans_handle *trans, + struct btrfs_block_group_cache *block_group, + struct btrfs_path *path) +{ + 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 objectid; + int ret; + + ret = btrfs_find_free_objectid(trans, root, 0, &objectid); + if (ret < 0) + return ret; + + ret = btrfs_insert_empty_inode(trans, root, path, objectid); + if (ret) + return ret; + + leaf = path->nodes[0]; + inode_item = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_inode_item); + btrfs_item_key(leaf, &disk_key, path->slots[0]); + memset_extent_buffer(leaf, 0, (unsigned long)inode_item, + sizeof(*inode_item)); + btrfs_set_inode_generation(leaf, inode_item, trans->transid); + btrfs_set_inode_size(leaf, inode_item, 0); + btrfs_set_inode_nbytes(leaf, inode_item, 0); + btrfs_set_inode_uid(leaf, inode_item, 0); + btrfs_set_inode_gid(leaf, inode_item, 0); + btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600); + btrfs_set_inode_flags(leaf, inode_item, BTRFS_INODE_NOCOMPRESS | + BTRFS_INODE_PREALLOC | BTRFS_INODE_NODATASUM); + btrfs_set_inode_nlink(leaf, inode_item, 1); + btrfs_set_inode_transid(leaf, inode_item, trans->transid); + btrfs_set_inode_block_group(leaf, inode_item, + block_group->key.objectid); + btrfs_mark_buffer_dirty(leaf); + btrfs_release_path(root, path); + + key.objectid = BTRFS_FREE_SPACE_OBJECTID; + key.offset = block_group->key.objectid; + key.type = 0; + + ret = btrfs_insert_empty_item(trans, root, path, &key, + sizeof(struct btrfs_free_space_header)); + if (ret < 0) { + btrfs_release_path(root, 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(root, path); + + return 0; +} + +int btrfs_truncate_free_space_cache(struct btrfs_root *root, + struct btrfs_trans_handle *trans, + struct btrfs_path *path, + struct inode *inode) +{ + loff_t oldsize; + int ret = 0; + + trans->block_rsv = root->orphan_block_rsv; + ret = btrfs_block_rsv_check(trans, root, + root->orphan_block_rsv, + 0, 5); + if (ret) + return ret; + + oldsize = i_size_read(inode); + btrfs_i_size_write(inode, 0); + truncate_pagecache(inode, oldsize, 0); + + /* + * We don't need an orphan item because truncating the free space cache + * will never be split across transactions. + */ + ret = btrfs_truncate_inode_items(trans, root, inode, + 0, BTRFS_EXTENT_DATA_KEY); + if (ret) { + WARN_ON(1); + return ret; + } + + return btrfs_update_inode(trans, root, inode); +} + +static int readahead_cache(struct inode *inode) +{ + struct file_ra_state *ra; + unsigned long last_index; + + ra = kzalloc(sizeof(*ra), GFP_NOFS); + if (!ra) + return -ENOMEM; + + file_ra_state_init(ra, inode->i_mapping); + last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; + + page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index); + + kfree(ra); + + return 0; +} + +int load_free_space_cache(struct btrfs_fs_info *fs_info, + struct btrfs_block_group_cache *block_group) +{ + struct btrfs_root *root = fs_info->tree_root; + struct inode *inode; + struct btrfs_free_space_header *header; + struct extent_buffer *leaf; + struct page *page; + struct btrfs_path *path; + u32 *checksums = NULL, *crc; + char *disk_crcs = NULL; + struct btrfs_key key; + struct list_head bitmaps; + u64 num_entries; + u64 num_bitmaps; + u64 generation; + u32 cur_crc = ~(u32)0; + pgoff_t index = 0; + unsigned long first_page_offset; + int num_checksums; + int ret = 0; + + /* + * 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. + */ + smp_mb(); + if (fs_info->closing) + return 0; + + /* + * If this block group has been marked to be cleared for one reason or + * another then we can't trust the on disk cache, so just return. + */ + spin_lock(&block_group->lock); + if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) { + spin_unlock(&block_group->lock); + return 0; + } + spin_unlock(&block_group->lock); + + INIT_LIST_HEAD(&bitmaps); + + path = btrfs_alloc_path(); + if (!path) + return 0; + + inode = lookup_free_space_inode(root, block_group, path); + if (IS_ERR(inode)) { + btrfs_free_path(path); + return 0; + } + + /* Nothing in the space cache, goodbye */ + if (!i_size_read(inode)) { + btrfs_free_path(path); + goto out; + } + + key.objectid = BTRFS_FREE_SPACE_OBJECTID; + key.offset = block_group->key.objectid; + key.type = 0; + + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret) { + btrfs_free_path(path); + goto out; + } + + 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_free_path(path); + + if (BTRFS_I(inode)->generation != generation) { + printk(KERN_ERR "btrfs: free space inode generation (%llu) did" + " not match free space cache generation (%llu) for " + "block group %llu\n", + (unsigned long long)BTRFS_I(inode)->generation, + (unsigned long long)generation, + (unsigned long long)block_group->key.objectid); + goto out; + } + + if (!num_entries) + goto out; + + /* Setup everything for doing checksumming */ + num_checksums = i_size_read(inode) / PAGE_CACHE_SIZE; + checksums = crc = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS); + if (!checksums) + goto out; + first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64); + disk_crcs = kzalloc(first_page_offset, GFP_NOFS); + if (!disk_crcs) + goto out; + + ret = readahead_cache(inode); + if (ret) { + ret = 0; + goto out; + } + + while (1) { + struct btrfs_free_space_entry *entry; + struct btrfs_free_space *e; + void *addr; + unsigned long offset = 0; + unsigned long start_offset = 0; + int need_loop = 0; + + if (!num_entries && !num_bitmaps) + break; + + if (index == 0) { + start_offset = first_page_offset; + offset = start_offset; + } + + page = grab_cache_page(inode->i_mapping, index); + if (!page) { + ret = 0; + goto free_cache; + } + + if (!PageUptodate(page)) { + btrfs_readpage(NULL, page); + lock_page(page); + if (!PageUptodate(page)) { + unlock_page(page); + page_cache_release(page); + printk(KERN_ERR "btrfs: error reading free " + "space cache: %llu\n", + (unsigned long long) + block_group->key.objectid); + goto free_cache; + } + } + addr = kmap(page); + + if (index == 0) { + u64 *gen; + + memcpy(disk_crcs, addr, first_page_offset); + gen = addr + (sizeof(u32) * num_checksums); + if (*gen != BTRFS_I(inode)->generation) { + printk(KERN_ERR "btrfs: space cache generation" + " (%llu) does not match inode (%llu) " + "for block group %llu\n", + (unsigned long long)*gen, + (unsigned long long) + BTRFS_I(inode)->generation, + (unsigned long long) + block_group->key.objectid); + kunmap(page); + unlock_page(page); + page_cache_release(page); + goto free_cache; + } + crc = (u32 *)disk_crcs; + } + entry = addr + start_offset; + + /* First lets check our crc before we do anything fun */ + cur_crc = ~(u32)0; + cur_crc = btrfs_csum_data(root, addr + start_offset, cur_crc, + PAGE_CACHE_SIZE - start_offset); + btrfs_csum_final(cur_crc, (char *)&cur_crc); + if (cur_crc != *crc) { + printk(KERN_ERR "btrfs: crc mismatch for page %lu in " + "block group %llu\n", index, + (unsigned long long)block_group->key.objectid); + kunmap(page); + unlock_page(page); + page_cache_release(page); + goto free_cache; + } + crc++; + + while (1) { + if (!num_entries) + break; + + need_loop = 1; + e = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS); + if (!e) { + kunmap(page); + unlock_page(page); + page_cache_release(page); + goto free_cache; + } + + e->offset = le64_to_cpu(entry->offset); + e->bytes = le64_to_cpu(entry->bytes); + if (!e->bytes) { + kunmap(page); + kfree(e); + unlock_page(page); + page_cache_release(page); + goto free_cache; + } + + if (entry->type == BTRFS_FREE_SPACE_EXTENT) { + spin_lock(&block_group->tree_lock); + ret = link_free_space(block_group, e); + spin_unlock(&block_group->tree_lock); + BUG_ON(ret); + } else { + e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS); + if (!e->bitmap) { + kunmap(page); + kfree(e); + unlock_page(page); + page_cache_release(page); + goto free_cache; + } + spin_lock(&block_group->tree_lock); + ret = link_free_space(block_group, e); + block_group->total_bitmaps++; + recalculate_thresholds(block_group); + spin_unlock(&block_group->tree_lock); + list_add_tail(&e->list, &bitmaps); + } + + num_entries--; + offset += sizeof(struct btrfs_free_space_entry); + if (offset + sizeof(struct btrfs_free_space_entry) >= + PAGE_CACHE_SIZE) + break; + entry++; + } + + /* + * We read an entry out of this page, we need to move on to the + * next page. + */ + if (need_loop) { + kunmap(page); + goto next; + } + + /* + * We add the bitmaps at the end of the entries in order that + * the bitmap entries are added to the cache. + */ + e = list_entry(bitmaps.next, struct btrfs_free_space, list); + list_del_init(&e->list); + memcpy(e->bitmap, addr, PAGE_CACHE_SIZE); + kunmap(page); + num_bitmaps--; +next: + unlock_page(page); + page_cache_release(page); + index++; + } + + ret = 1; +out: + kfree(checksums); + kfree(disk_crcs); + iput(inode); + return ret; + +free_cache: + /* 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); + btrfs_remove_free_space_cache(block_group); + 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_header *header; + struct extent_buffer *leaf; + struct inode *inode; + struct rb_node *node; + struct list_head *pos, *n; + struct page *page; + struct extent_state *cached_state = NULL; + struct list_head bitmap_list; + struct btrfs_key key; + u64 bytes = 0; + u32 *crc, *checksums; + pgoff_t index = 0, last_index = 0; + unsigned long first_page_offset; + int num_checksums; + int entries = 0; + int bitmaps = 0; + int ret = 0; + + root = root->fs_info->tree_root; + + INIT_LIST_HEAD(&bitmap_list); + + 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; + + if (!i_size_read(inode)) { + iput(inode); + return 0; + } + + last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; + filemap_write_and_wait(inode->i_mapping); + btrfs_wait_ordered_range(inode, inode->i_size & + ~(root->sectorsize - 1), (u64)-1); + + /* We need a checksum per page. */ + num_checksums = i_size_read(inode) / PAGE_CACHE_SIZE; + crc = checksums = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS); + if (!crc) { + iput(inode); + return 0; + } + + /* Since the first page has all of our checksums and our generation we + * need to calculate the offset into the page that we can start writing + * our entries. + */ + first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64); + + node = rb_first(&block_group->free_space_offset); + if (!node) + goto out_free; + + /* + * Lock all pages first so we can lock the extent safely. + * + * NOTE: Because we hold the ref the entire time we're going to write to + * the page find_get_page should never fail, so we don't do a check + * after find_get_page at this point. Just putting this here so people + * know and don't freak out. + */ + while (index <= last_index) { + page = grab_cache_page(inode->i_mapping, index); + if (!page) { + pgoff_t i = 0; + + while (i < index) { + page = find_get_page(inode->i_mapping, i); + unlock_page(page); + page_cache_release(page); + page_cache_release(page); + i++; + } + goto out_free; + } + index++; + } + + index = 0; + lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1, + 0, &cached_state, GFP_NOFS); + + /* Write out the extent entries */ + do { + struct btrfs_free_space_entry *entry; + void *addr; + unsigned long offset = 0; + unsigned long start_offset = 0; + + if (index == 0) { + start_offset = first_page_offset; + offset = start_offset; + } + + page = find_get_page(inode->i_mapping, index); + + addr = kmap(page); + entry = addr + start_offset; + + memset(addr, 0, PAGE_CACHE_SIZE); + while (1) { + struct btrfs_free_space *e; + + e = rb_entry(node, struct btrfs_free_space, offset_index); + entries++; + + entry->offset = cpu_to_le64(e->offset); + entry->bytes = cpu_to_le64(e->bytes); + if (e->bitmap) { + entry->type = BTRFS_FREE_SPACE_BITMAP; + list_add_tail(&e->list, &bitmap_list); + bitmaps++; + } else { + entry->type = BTRFS_FREE_SPACE_EXTENT; + } + node = rb_next(node); + if (!node) + break; + offset += sizeof(struct btrfs_free_space_entry); + if (offset + sizeof(struct btrfs_free_space_entry) >= + PAGE_CACHE_SIZE) + break; + entry++; + } + *crc = ~(u32)0; + *crc = btrfs_csum_data(root, addr + start_offset, *crc, + PAGE_CACHE_SIZE - start_offset); + kunmap(page); + + btrfs_csum_final(*crc, (char *)crc); + crc++; + + bytes += PAGE_CACHE_SIZE; + + ClearPageChecked(page); + set_page_extent_mapped(page); + SetPageUptodate(page); + set_page_dirty(page); + + /* + * We need to release our reference we got for grab_cache_page, + * except for the first page which will hold our checksums, we + * do that below. + */ + if (index != 0) { + unlock_page(page); + page_cache_release(page); + } + + page_cache_release(page); + + index++; + } while (node); + + /* Write out the bitmaps */ + list_for_each_safe(pos, n, &bitmap_list) { + void *addr; + struct btrfs_free_space *entry = + list_entry(pos, struct btrfs_free_space, list); + + page = find_get_page(inode->i_mapping, index); + + addr = kmap(page); + memcpy(addr, entry->bitmap, PAGE_CACHE_SIZE); + *crc = ~(u32)0; + *crc = btrfs_csum_data(root, addr, *crc, PAGE_CACHE_SIZE); + kunmap(page); + btrfs_csum_final(*crc, (char *)crc); + crc++; + bytes += PAGE_CACHE_SIZE; + + ClearPageChecked(page); + set_page_extent_mapped(page); + SetPageUptodate(page); + set_page_dirty(page); + unlock_page(page); + page_cache_release(page); + page_cache_release(page); + list_del_init(&entry->list); + index++; + } + + /* Zero out the rest of the pages just to make sure */ + while (index <= last_index) { + void *addr; + + page = find_get_page(inode->i_mapping, index); + + addr = kmap(page); + memset(addr, 0, PAGE_CACHE_SIZE); + kunmap(page); + ClearPageChecked(page); + set_page_extent_mapped(page); + SetPageUptodate(page); + set_page_dirty(page); + unlock_page(page); + page_cache_release(page); + page_cache_release(page); + bytes += PAGE_CACHE_SIZE; + index++; + } + + btrfs_set_extent_delalloc(inode, 0, bytes - 1, &cached_state); + + /* Write the checksums and trans id to the first page */ + { + void *addr; + u64 *gen; + + page = find_get_page(inode->i_mapping, 0); + + addr = kmap(page); + memcpy(addr, checksums, sizeof(u32) * num_checksums); + gen = addr + (sizeof(u32) * num_checksums); + *gen = trans->transid; + kunmap(page); + ClearPageChecked(page); + set_page_extent_mapped(page); + SetPageUptodate(page); + set_page_dirty(page); + unlock_page(page); + page_cache_release(page); + page_cache_release(page); + } + BTRFS_I(inode)->generation = trans->transid; + + unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0, + i_size_read(inode) - 1, &cached_state, GFP_NOFS); + + filemap_write_and_wait(inode->i_mapping); + + key.objectid = BTRFS_FREE_SPACE_OBJECTID; + key.offset = block_group->key.objectid; + key.type = 0; + + ret = btrfs_search_slot(trans, root, &key, path, 1, 1); + if (ret < 0) { + ret = 0; + clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1, + EXTENT_DIRTY | EXTENT_DELALLOC | + EXTENT_DO_ACCOUNTING, 0, 0, NULL, GFP_NOFS); + goto out_free; + } + leaf = path->nodes[0]; + if (ret > 0) { + struct btrfs_key found_key; + BUG_ON(!path->slots[0]); + path->slots[0]--; + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); + if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID || + found_key.offset != block_group->key.objectid) { + ret = 0; + clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1, + EXTENT_DIRTY | EXTENT_DELALLOC | + EXTENT_DO_ACCOUNTING, 0, 0, NULL, + GFP_NOFS); + btrfs_release_path(root, path); + goto out_free; + } + } + header = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_free_space_header); + btrfs_set_free_space_entries(leaf, header, entries); + btrfs_set_free_space_bitmaps(leaf, header, bitmaps); + btrfs_set_free_space_generation(leaf, header, trans->transid); + btrfs_mark_buffer_dirty(leaf); + btrfs_release_path(root, path); + + ret = 1; + +out_free: + if (ret == 0) { + invalidate_inode_pages2_range(inode->i_mapping, 0, index); + spin_lock(&block_group->lock); + block_group->disk_cache_state = BTRFS_DC_ERROR; + spin_unlock(&block_group->lock); + BTRFS_I(inode)->generation = 0; + } + kfree(checksums); + btrfs_update_inode(trans, root, inode); + iput(inode); + return ret; +} + static inline unsigned long offset_to_bit(u64 bitmap_start, u64 sectorsize, u64 offset) { |