diff options
Diffstat (limited to 'fs/hfsplus/xattr.c')
| -rw-r--r-- | fs/hfsplus/xattr.c | 210 |
1 files changed, 208 insertions, 2 deletions
diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c index bd8471fb9a6..3c6136f98c7 100644 --- a/fs/hfsplus/xattr.c +++ b/fs/hfsplus/xattr.c @@ -127,6 +127,211 @@ static int can_set_xattr(struct inode *inode, const char *name, return 0; } +static void hfsplus_init_header_node(struct inode *attr_file, + u32 clump_size, + char *buf, u16 node_size) +{ + struct hfs_bnode_desc *desc; + struct hfs_btree_header_rec *head; + u16 offset; + __be16 *rec_offsets; + u32 hdr_node_map_rec_bits; + char *bmp; + u32 used_nodes; + u32 used_bmp_bytes; + loff_t tmp; + + hfs_dbg(ATTR_MOD, "init_hdr_attr_file: clump %u, node_size %u\n", + clump_size, node_size); + + /* The end of the node contains list of record offsets */ + rec_offsets = (__be16 *)(buf + node_size); + + desc = (struct hfs_bnode_desc *)buf; + desc->type = HFS_NODE_HEADER; + desc->num_recs = cpu_to_be16(HFSPLUS_BTREE_HDR_NODE_RECS_COUNT); + offset = sizeof(struct hfs_bnode_desc); + *--rec_offsets = cpu_to_be16(offset); + + head = (struct hfs_btree_header_rec *)(buf + offset); + head->node_size = cpu_to_be16(node_size); + tmp = i_size_read(attr_file); + do_div(tmp, node_size); + head->node_count = cpu_to_be32(tmp); + head->free_nodes = cpu_to_be32(be32_to_cpu(head->node_count) - 1); + head->clump_size = cpu_to_be32(clump_size); + head->attributes |= cpu_to_be32(HFS_TREE_BIGKEYS | HFS_TREE_VARIDXKEYS); + head->max_key_len = cpu_to_be16(HFSPLUS_ATTR_KEYLEN - sizeof(u16)); + offset += sizeof(struct hfs_btree_header_rec); + *--rec_offsets = cpu_to_be16(offset); + offset += HFSPLUS_BTREE_HDR_USER_BYTES; + *--rec_offsets = cpu_to_be16(offset); + + hdr_node_map_rec_bits = 8 * (node_size - offset - (4 * sizeof(u16))); + if (be32_to_cpu(head->node_count) > hdr_node_map_rec_bits) { + u32 map_node_bits; + u32 map_nodes; + + desc->next = cpu_to_be32(be32_to_cpu(head->leaf_tail) + 1); + map_node_bits = 8 * (node_size - sizeof(struct hfs_bnode_desc) - + (2 * sizeof(u16)) - 2); + map_nodes = (be32_to_cpu(head->node_count) - + hdr_node_map_rec_bits + + (map_node_bits - 1)) / map_node_bits; + be32_add_cpu(&head->free_nodes, 0 - map_nodes); + } + + bmp = buf + offset; + used_nodes = + be32_to_cpu(head->node_count) - be32_to_cpu(head->free_nodes); + used_bmp_bytes = used_nodes / 8; + if (used_bmp_bytes) { + memset(bmp, 0xFF, used_bmp_bytes); + bmp += used_bmp_bytes; + used_nodes %= 8; + } + *bmp = ~(0xFF >> used_nodes); + offset += hdr_node_map_rec_bits / 8; + *--rec_offsets = cpu_to_be16(offset); +} + +static int hfsplus_create_attributes_file(struct super_block *sb) +{ + int err = 0; + struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); + struct inode *attr_file; + struct hfsplus_inode_info *hip; + u32 clump_size; + u16 node_size = HFSPLUS_ATTR_TREE_NODE_SIZE; + char *buf; + int index, written; + struct address_space *mapping; + struct page *page; + int old_state = HFSPLUS_EMPTY_ATTR_TREE; + + hfs_dbg(ATTR_MOD, "create_attr_file: ino %d\n", HFSPLUS_ATTR_CNID); + +check_attr_tree_state_again: + switch (atomic_read(&sbi->attr_tree_state)) { + case HFSPLUS_EMPTY_ATTR_TREE: + if (old_state != atomic_cmpxchg(&sbi->attr_tree_state, + old_state, + HFSPLUS_CREATING_ATTR_TREE)) + goto check_attr_tree_state_again; + break; + case HFSPLUS_CREATING_ATTR_TREE: + /* + * This state means that another thread is in process + * of AttributesFile creation. Theoretically, it is + * possible to be here. But really __setxattr() method + * first of all calls hfs_find_init() for lookup in + * B-tree of CatalogFile. This method locks mutex of + * CatalogFile's B-tree. As a result, if some thread + * is inside AttributedFile creation operation then + * another threads will be waiting unlocking of + * CatalogFile's B-tree's mutex. However, if code will + * change then we will return error code (-EAGAIN) from + * here. Really, it means that first try to set of xattr + * fails with error but second attempt will have success. + */ + return -EAGAIN; + case HFSPLUS_VALID_ATTR_TREE: + return 0; + case HFSPLUS_FAILED_ATTR_TREE: + return -EOPNOTSUPP; + default: + BUG(); + } + + attr_file = hfsplus_iget(sb, HFSPLUS_ATTR_CNID); + if (IS_ERR(attr_file)) { + pr_err("failed to load attributes file\n"); + return PTR_ERR(attr_file); + } + + BUG_ON(i_size_read(attr_file) != 0); + + hip = HFSPLUS_I(attr_file); + + clump_size = hfsplus_calc_btree_clump_size(sb->s_blocksize, + node_size, + sbi->sect_count, + HFSPLUS_ATTR_CNID); + + mutex_lock(&hip->extents_lock); + hip->clump_blocks = clump_size >> sbi->alloc_blksz_shift; + mutex_unlock(&hip->extents_lock); + + if (sbi->free_blocks <= (hip->clump_blocks << 1)) { + err = -ENOSPC; + goto end_attr_file_creation; + } + + while (hip->alloc_blocks < hip->clump_blocks) { + err = hfsplus_file_extend(attr_file); + if (unlikely(err)) { + pr_err("failed to extend attributes file\n"); + goto end_attr_file_creation; + } + hip->phys_size = attr_file->i_size = + (loff_t)hip->alloc_blocks << sbi->alloc_blksz_shift; + hip->fs_blocks = hip->alloc_blocks << sbi->fs_shift; + inode_set_bytes(attr_file, attr_file->i_size); + } + + buf = kzalloc(node_size, GFP_NOFS); + if (!buf) { + pr_err("failed to allocate memory for header node\n"); + err = -ENOMEM; + goto end_attr_file_creation; + } + + hfsplus_init_header_node(attr_file, clump_size, buf, node_size); + + mapping = attr_file->i_mapping; + + index = 0; + written = 0; + for (; written < node_size; index++, written += PAGE_CACHE_SIZE) { + void *kaddr; + + page = read_mapping_page(mapping, index, NULL); + if (IS_ERR(page)) { + err = PTR_ERR(page); + goto failed_header_node_init; + } + + kaddr = kmap_atomic(page); + memcpy(kaddr, buf + written, + min_t(size_t, PAGE_CACHE_SIZE, node_size - written)); + kunmap_atomic(kaddr); + + set_page_dirty(page); + page_cache_release(page); + } + + hfsplus_mark_inode_dirty(attr_file, HFSPLUS_I_ATTR_DIRTY); + + sbi->attr_tree = hfs_btree_open(sb, HFSPLUS_ATTR_CNID); + if (!sbi->attr_tree) + pr_err("failed to load attributes file\n"); + +failed_header_node_init: + kfree(buf); + +end_attr_file_creation: + iput(attr_file); + + if (!err) + atomic_set(&sbi->attr_tree_state, HFSPLUS_VALID_ATTR_TREE); + else if (err == -ENOSPC) + atomic_set(&sbi->attr_tree_state, HFSPLUS_EMPTY_ATTR_TREE); + else + atomic_set(&sbi->attr_tree_state, HFSPLUS_FAILED_ATTR_TREE); + + return err; +} + int __hfsplus_setxattr(struct inode *inode, const char *name, const void *value, size_t size, int flags) { @@ -211,8 +416,9 @@ int __hfsplus_setxattr(struct inode *inode, const char *name, } if (!HFSPLUS_SB(inode->i_sb)->attr_tree) { - err = -EOPNOTSUPP; - goto end_setxattr; + err = hfsplus_create_attributes_file(inode->i_sb); + if (unlikely(err)) + goto end_setxattr; } if (hfsplus_attr_exists(inode, name)) { |