diff options
Diffstat (limited to 'fs/hfsplus/xattr.c')
| -rw-r--r-- | fs/hfsplus/xattr.c | 142 |
1 files changed, 140 insertions, 2 deletions
diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c index 568a45cb1145..efc85b1377cc 100644 --- a/fs/hfsplus/xattr.c +++ b/fs/hfsplus/xattr.c @@ -192,6 +192,143 @@ static void hfsplus_init_header_node(struct inode *attr_file, *--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) { @@ -276,8 +413,9 @@ 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)) { |