#include <linux/module.h> #include <linux/fs.h> #include <linux/blkdev.h> #include <linux/crypto.h> #include <linux/scatterlist.h> #include <linux/swap.h> #include <linux/radix-tree.h> #include "ctree.h" #include "disk-io.h" #include "transaction.h" #include "btrfs_inode.h" static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf) { struct btrfs_node *node = btrfs_buffer_node(buf); if (buf->b_blocknr != btrfs_header_blocknr(&node->header)) { BUG(); } return 0; } struct buffer_head *btrfs_find_tree_block(struct btrfs_root *root, u64 blocknr) { struct address_space *mapping = root->fs_info->btree_inode->i_mapping; int blockbits = root->fs_info->sb->s_blocksize_bits; unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits); struct page *page; struct buffer_head *bh; struct buffer_head *head; struct buffer_head *ret = NULL; page = find_lock_page(mapping, index); if (!page) return NULL; if (!page_has_buffers(page)) goto out_unlock; head = page_buffers(page); bh = head; do { if (buffer_mapped(bh) && bh->b_blocknr == blocknr) { ret = bh; get_bh(bh); goto out_unlock; } bh = bh->b_this_page; } while (bh != head); out_unlock: unlock_page(page); if (ret) { touch_buffer(ret); } page_cache_release(page); return ret; } struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root, u64 blocknr) { struct address_space *mapping = root->fs_info->btree_inode->i_mapping; int blockbits = root->fs_info->sb->s_blocksize_bits; unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits); struct page *page; struct buffer_head *bh; struct buffer_head *head; struct buffer_head *ret = NULL; u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits); page = grab_cache_page(mapping, index); if (!page) return NULL; if (!page_has_buffers(page)) create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0); head = page_buffers(page); bh = head; do { if (!buffer_mapped(bh)) { bh->b_bdev = root->fs_info->sb->s_bdev; bh->b_blocknr = first_block; set_buffer_mapped(bh); } if (bh->b_blocknr == blocknr) { ret = bh; get_bh(bh); goto out_unlock; } bh = bh->b_this_page; first_block++; } while (bh != head); out_unlock: unlock_page(page); if (ret) touch_buffer(ret); page_cache_release(page); return ret; } static sector_t max_block(struct block_device *bdev) { sector_t retval = ~((sector_t)0); loff_t sz = i_size_read(bdev->bd_inode); if (sz) { unsigned int size = block_size(bdev); unsigned int sizebits = blksize_bits(size); retval = (sz >> sizebits); } return retval; } static int btree_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh, int create) { if (iblock >= max_block(inode->i_sb->s_bdev)) { if (create) return -EIO; /* * for reads, we're just trying to fill a partial page. * return a hole, they will have to call get_block again * before they can fill it, and they will get -EIO at that * time */ return 0; } bh->b_bdev = inode->i_sb->s_bdev; bh->b_blocknr = iblock; set_buffer_mapped(bh); return 0; } int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len, char *result) { struct scatterlist sg; struct crypto_hash *tfm = root->fs_info->hash_tfm; struct hash_desc desc; int ret; desc.tfm = tfm; desc.flags = 0; sg_init_one(&sg, data, len); spin_lock(&root->fs_info->hash_lock); ret = crypto_hash_digest(&desc, &sg, 1, result); spin_unlock(&root->fs_info->hash_lock); if (ret) { printk("sha256 digest failed\n"); } return ret; } static int csum_tree_block(struct btrfs_root *root, struct buffer_head *bh, int verify) { char result[BTRFS_CSUM_SIZE]; int ret; struct btrfs_node *node; ret = btrfs_csum_data(root, bh->b_data + BTRFS_CSUM_SIZE, bh->b_size - BTRFS_CSUM_SIZE, result); if (ret) return ret; if (verify) { if (memcmp(bh->b_data, result, BTRFS_CSUM_SIZE)) { printk("checksum verify failed on %lu\n", bh->b_blocknr); return 1; } } else { node = btrfs_buffer_node(bh); memcpy(node->header.csum, result, BTRFS_CSUM_SIZE); } return 0; } static int btree_writepage(struct page *page, struct writeback_control *wbc) { struct buffer_head *bh; struct btrfs_root *root = BTRFS_I(page->mapping->host)->root; struct buffer_head *head; if (!page_has_buffers(page)) { create_empty_buffers(page, root->fs_info->sb->s_blocksize, (1 << BH_Dirty)|(1 << BH_Uptodate)); } head = page_buffers(page); bh = head; do { if (buffer_dirty(bh)) csum_tree_block(root, bh, 0); bh = bh->b_this_page; } while (bh != head); return block_write_full_page(page, btree_get_block, wbc); } static int btree_readpage(struct file * file, struct page * page) { return block_read_full_page(page, btree_get_block); } static struct address_space_operations btree_aops = { .readpage = btree_readpage, .writepage = btree_writepage, .sync_page = block_sync_page, }; struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr) { struct buffer_head *bh = NULL; bh = btrfs_find_create_tree_block(root, blocknr); if (!bh) return bh; if (buffer_uptodate(bh)) goto uptodate; lock_buffer(bh); if (!buffer_uptodate(bh)) { get_bh(bh); bh->b_end_io = end_buffer_read_sync; submit_bh(READ, bh); wait_on_buffer(bh); if (!buffer_uptodate(bh)) goto fail; csum_tree_block(root, bh, 1); } else { unlock_buffer(bh); } uptodate: if (check_tree_block(root, bh)) BUG(); return bh; fail: brelse(bh); return NULL; } int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct buffer_head *buf) { WARN_ON(atomic_read(&buf->b_count) == 0); mark_buffer_dirty(buf); return 0; } int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct buffer_head *buf) { WARN_ON(atomic_read(&buf->b_count) == 0); clear_buffer_dirty(buf); return 0; } static int __setup_root(int blocksize, struct btrfs_root *root, struct btrfs_fs_info *fs_info, u64 objectid) { root->node = NULL; root->inode = NULL; root->commit_root = NULL; root->blocksize = blocksize; root->ref_cows = 0; root->fs_info = fs_info; root->objectid = objectid; root->last_trans = 0; root->highest_inode = 0; root->last_inode_alloc = 0; memset(&root->root_key, 0, sizeof(root->root_key)); memset(&root->root_item, 0, sizeof(root->root_item)); return 0; } static int find_and_setup_root(int blocksize, struct btrfs_root *tree_root, struct btrfs_fs_info *fs_info, u64 objectid, struct btrfs_root *root) { int ret; __setup_root(blocksize, root, fs_info, objectid); ret = btrfs_find_last_root(tree_root, objectid, &root->root_item, &root->root_key); BUG_ON(ret); root->node = read_tree_block(root, btrfs_root_blocknr(&root->root_item)); BUG_ON(!root->node); return 0; } struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_key *location) { struct btrfs_root *root; struct btrfs_root *tree_root = fs_info->tree_root; struct btrfs_path *path; struct btrfs_leaf *l; u64 highest_inode; int ret = 0; printk("read_fs_root looking for %Lu %Lu %u\n", location->objectid, location->offset, location->flags); root = kmalloc(sizeof(*root), GFP_NOFS); if (!root) { printk("failed1\n"); return ERR_PTR(-ENOMEM); } if (location->offset == (u64)-1) { ret = find_and_setup_root(fs_info->sb->s_blocksize, fs_info->tree_root, fs_info, location->objectid, root); if (ret) { printk("failed2\n"); kfree(root); return ERR_PTR(ret); } goto insert; } __setup_root(fs_info->sb->s_blocksize, root, fs_info, location->objectid); path = btrfs_alloc_path(); BUG_ON(!path); ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0); if (ret != 0) { printk("internal search_slot gives us %d\n", ret); if (ret > 0) ret = -ENOENT; goto out; } l = btrfs_buffer_leaf(path->nodes[0]); memcpy(&root->root_item, btrfs_item_ptr(l, path->slots[0], struct btrfs_root_item), sizeof(root->root_item)); memcpy(&root->root_key, location, sizeof(*location)); ret = 0; out: btrfs_release_path(root, path); btrfs_free_path(path); if (ret) { kfree(root); return ERR_PTR(ret); } root->node = read_tree_block(root, btrfs_root_blocknr(&root->root_item)); BUG_ON(!root->node); insert: printk("inserting %p\n", root); root->ref_cows = 1; ret = radix_tree_insert(&fs_info->fs_roots_radix, (unsigned long)root, root); if (ret) { printk("radix_tree_insert gives us %d\n", ret); brelse(root->node); kfree(root); return ERR_PTR(ret); } ret = btrfs_find_highest_inode(root, &highest_inode); if (ret == 0) { root->highest_inode = highest_inode; root->last_inode_alloc = highest_inode; printk("highest inode is %Lu\n", highest_inode); } printk("all worked\n"); return root; } struct btrfs_root *open_ctree(struct super_block *sb) { struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root), GFP_NOFS); struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root), GFP_NOFS); struct btrfs_fs_info *fs_info = kmalloc(sizeof(*fs_info), GFP_NOFS); int ret; struct btrfs_super_block *disk_super; init_bit_radix(&fs_info->pinned_radix); init_bit_radix(&fs_info->pending_del_radix); INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS); sb_set_blocksize(sb, 4096); fs_info->running_transaction = NULL; fs_info->tree_root = tree_root; fs_info->extent_root = extent_root; fs_info->sb = sb; fs_info->btree_inode = new_inode(sb); fs_info->btree_inode->i_ino = 1; fs_info->btree_inode->i_nlink = 1; fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size; fs_info->btree_inode->i_mapping->a_ops = &btree_aops; BTRFS_I(fs_info->btree_inode)->root = tree_root; memset(&BTRFS_I(fs_info->btree_inode)->location, 0, sizeof(struct btrfs_key)); insert_inode_hash(fs_info->btree_inode); mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS); fs_info->hash_tfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC); spin_lock_init(&fs_info->hash_lock); if (!fs_info->hash_tfm || IS_ERR(fs_info->hash_tfm)) { printk("failed to allocate sha256 hash\n"); return NULL; } mutex_init(&fs_info->trans_mutex); mutex_init(&fs_info->fs_mutex); memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert)); memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert)); __setup_root(sb->s_blocksize, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID); fs_info->sb_buffer = read_tree_block(tree_root, BTRFS_SUPER_INFO_OFFSET / sb->s_blocksize); if (!fs_info->sb_buffer) return NULL; disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data; if (!btrfs_super_root(disk_super)) return NULL; fs_info->disk_super = disk_super; tree_root->node = read_tree_block(tree_root, btrfs_super_root(disk_super)); BUG_ON(!tree_root->node); mutex_lock(&fs_info->fs_mutex); ret = find_and_setup_root(sb->s_blocksize, tree_root, fs_info, BTRFS_EXTENT_TREE_OBJECTID, extent_root); BUG_ON(ret); fs_info->generation = btrfs_super_generation(disk_super) + 1; memset(&fs_info->kobj, 0, sizeof(fs_info->kobj)); kobj_set_kset_s(fs_info, btrfs_subsys); kobject_set_name(&fs_info->kobj, "%s", sb->s_id); kobject_register(&fs_info->kobj); mutex_unlock(&fs_info->fs_mutex); return tree_root; } int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct buffer_head *bh = root->fs_info->sb_buffer; btrfs_set_super_root(root->fs_info->disk_super, root->fs_info->tree_root->node->b_blocknr); lock_buffer(bh); WARN_ON(atomic_read(&bh->b_count) < 1); clear_buffer_dirty(bh); csum_tree_block(root, bh, 0); bh->b_end_io = end_buffer_write_sync; get_bh(bh); submit_bh(WRITE, bh); wait_on_buffer(bh); if (!buffer_uptodate(bh)) { WARN_ON(1); return -EIO; } return 0; } int del_fs_roots(struct btrfs_fs_info *fs_info) { int ret; struct btrfs_root *gang[8]; int i; while(1) { ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix, (void **)gang, 0, ARRAY_SIZE(gang)); if (!ret) break; for (i = 0; i < ret; i++) { radix_tree_delete(&fs_info->fs_roots_radix, (unsigned long)gang[i]); if (gang[i]->inode) iput(gang[i]->inode); else printk("no inode for root %p\n", gang[i]); if (gang[i]->node) brelse(gang[i]->node); if (gang[i]->commit_root) brelse(gang[i]->commit_root); kfree(gang[i]); } } return 0; } int close_ctree(struct btrfs_root *root) { int ret; struct btrfs_trans_handle *trans; struct btrfs_fs_info *fs_info = root->fs_info; mutex_lock(&fs_info->fs_mutex); trans = btrfs_start_transaction(root, 1); btrfs_commit_transaction(trans, root); /* run commit again to drop the original snapshot */ trans = btrfs_start_transaction(root, 1); btrfs_commit_transaction(trans, root); ret = btrfs_write_and_wait_transaction(NULL, root); BUG_ON(ret); write_ctree_super(NULL, root); mutex_unlock(&fs_info->fs_mutex); if (fs_info->extent_root->node) btrfs_block_release(fs_info->extent_root, fs_info->extent_root->node); if (fs_info->tree_root->node) btrfs_block_release(fs_info->tree_root, fs_info->tree_root->node); btrfs_block_release(root, fs_info->sb_buffer); crypto_free_hash(fs_info->hash_tfm); truncate_inode_pages(fs_info->btree_inode->i_mapping, 0); iput(fs_info->btree_inode); del_fs_roots(fs_info); kfree(fs_info->extent_root); kfree(fs_info->tree_root); kobject_unregister(&fs_info->kobj); return 0; } void btrfs_block_release(struct btrfs_root *root, struct buffer_head *buf) { brelse(buf); }