diff options
Diffstat (limited to 'fs/btrfs/free-space-cache.c')
| -rw-r--r-- | fs/btrfs/free-space-cache.c | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index 05efcc7061a7..7f972e59cc04 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -28,6 +28,11 @@ #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) @@ -182,6 +187,303 @@ int btrfs_truncate_free_space_cache(struct btrfs_root *root, return btrfs_update_inode(trans, root, inode); } +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) { |