diff options
Diffstat (limited to 'fs/btrfs/props.c')
| -rw-r--r-- | fs/btrfs/props.c | 427 |
1 files changed, 427 insertions, 0 deletions
diff --git a/fs/btrfs/props.c b/fs/btrfs/props.c new file mode 100644 index 000000000000..129b1dd28527 --- /dev/null +++ b/fs/btrfs/props.c @@ -0,0 +1,427 @@ +/* + * Copyright (C) 2014 Filipe David Borba Manana <fdmanana@gmail.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +#include <linux/hashtable.h> +#include "props.h" +#include "btrfs_inode.h" +#include "hash.h" +#include "transaction.h" +#include "xattr.h" + +#define BTRFS_PROP_HANDLERS_HT_BITS 8 +static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS); + +struct prop_handler { + struct hlist_node node; + const char *xattr_name; + int (*validate)(const char *value, size_t len); + int (*apply)(struct inode *inode, const char *value, size_t len); + const char *(*extract)(struct inode *inode); + int inheritable; +}; + +static int prop_compression_validate(const char *value, size_t len); +static int prop_compression_apply(struct inode *inode, + const char *value, + size_t len); +static const char *prop_compression_extract(struct inode *inode); + +static struct prop_handler prop_handlers[] = { + { + .xattr_name = XATTR_BTRFS_PREFIX "compression", + .validate = prop_compression_validate, + .apply = prop_compression_apply, + .extract = prop_compression_extract, + .inheritable = 1 + }, + { + .xattr_name = NULL + } +}; + +void __init btrfs_props_init(void) +{ + struct prop_handler *p; + + hash_init(prop_handlers_ht); + + for (p = &prop_handlers[0]; p->xattr_name; p++) { + u64 h = btrfs_name_hash(p->xattr_name, strlen(p->xattr_name)); + + hash_add(prop_handlers_ht, &p->node, h); + } +} + +static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash) +{ + struct hlist_head *h; + + h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)]; + if (hlist_empty(h)) + return NULL; + + return h; +} + +static const struct prop_handler * +find_prop_handler(const char *name, + const struct hlist_head *handlers) +{ + struct prop_handler *h; + + if (!handlers) { + u64 hash = btrfs_name_hash(name, strlen(name)); + + handlers = find_prop_handlers_by_hash(hash); + if (!handlers) + return NULL; + } + + hlist_for_each_entry(h, handlers, node) + if (!strcmp(h->xattr_name, name)) + return h; + + return NULL; +} + +static int __btrfs_set_prop(struct btrfs_trans_handle *trans, + struct inode *inode, + const char *name, + const char *value, + size_t value_len, + int flags) +{ + const struct prop_handler *handler; + int ret; + + if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN) + return -EINVAL; + + handler = find_prop_handler(name, NULL); + if (!handler) + return -EINVAL; + + if (value_len == 0) { + ret = __btrfs_setxattr(trans, inode, handler->xattr_name, + NULL, 0, flags); + if (ret) + return ret; + + ret = handler->apply(inode, NULL, 0); + ASSERT(ret == 0); + + return ret; + } + + ret = handler->validate(value, value_len); + if (ret) + return ret; + ret = __btrfs_setxattr(trans, inode, handler->xattr_name, + value, value_len, flags); + if (ret) + return ret; + ret = handler->apply(inode, value, value_len); + if (ret) { + __btrfs_setxattr(trans, inode, handler->xattr_name, + NULL, 0, flags); + return ret; + } + + set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags); + + return 0; +} + +int btrfs_set_prop(struct inode *inode, + const char *name, + const char *value, + size_t value_len, + int flags) +{ + return __btrfs_set_prop(NULL, inode, name, value, value_len, flags); +} + +static int iterate_object_props(struct btrfs_root *root, + struct btrfs_path *path, + u64 objectid, + void (*iterator)(void *, + const struct prop_handler *, + const char *, + size_t), + void *ctx) +{ + int ret; + char *name_buf = NULL; + char *value_buf = NULL; + int name_buf_len = 0; + int value_buf_len = 0; + + while (1) { + struct btrfs_key key; + struct btrfs_dir_item *di; + struct extent_buffer *leaf; + u32 total_len, cur, this_len; + int slot; + const struct hlist_head *handlers; + + slot = path->slots[0]; + leaf = path->nodes[0]; + + if (slot >= btrfs_header_nritems(leaf)) { + ret = btrfs_next_leaf(root, path); + if (ret < 0) + goto out; + else if (ret > 0) + break; + continue; + } + + btrfs_item_key_to_cpu(leaf, &key, slot); + if (key.objectid != objectid) + break; + if (key.type != BTRFS_XATTR_ITEM_KEY) + break; + + handlers = find_prop_handlers_by_hash(key.offset); + if (!handlers) + goto next_slot; + + di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); + cur = 0; + total_len = btrfs_item_size_nr(leaf, slot); + + while (cur < total_len) { + u32 name_len = btrfs_dir_name_len(leaf, di); + u32 data_len = btrfs_dir_data_len(leaf, di); + unsigned long name_ptr, data_ptr; + const struct prop_handler *handler; + + this_len = sizeof(*di) + name_len + data_len; + name_ptr = (unsigned long)(di + 1); + data_ptr = name_ptr + name_len; + + if (name_len <= XATTR_BTRFS_PREFIX_LEN || + memcmp_extent_buffer(leaf, XATTR_BTRFS_PREFIX, + name_ptr, + XATTR_BTRFS_PREFIX_LEN)) + goto next_dir_item; + + if (name_len >= name_buf_len) { + kfree(name_buf); + name_buf_len = name_len + 1; + name_buf = kmalloc(name_buf_len, GFP_NOFS); + if (!name_buf) { + ret = -ENOMEM; + goto out; + } + } + read_extent_buffer(leaf, name_buf, name_ptr, name_len); + name_buf[name_len] = '\0'; + + handler = find_prop_handler(name_buf, handlers); + if (!handler) + goto next_dir_item; + + if (data_len > value_buf_len) { + kfree(value_buf); + value_buf_len = data_len; + value_buf = kmalloc(data_len, GFP_NOFS); + if (!value_buf) { + ret = -ENOMEM; + goto out; + } + } + read_extent_buffer(leaf, value_buf, data_ptr, data_len); + + iterator(ctx, handler, value_buf, data_len); +next_dir_item: + cur += this_len; + di = (struct btrfs_dir_item *)((char *) di + this_len); + } + +next_slot: + path->slots[0]++; + } + + ret = 0; +out: + btrfs_release_path(path); + kfree(name_buf); + kfree(value_buf); + + return ret; +} + +static void inode_prop_iterator(void *ctx, + const struct prop_handler *handler, + const char *value, + size_t len) +{ + struct inode *inode = ctx; + struct btrfs_root *root = BTRFS_I(inode)->root; + int ret; + + ret = handler->apply(inode, value, len); + if (unlikely(ret)) + btrfs_warn(root->fs_info, + "error applying prop %s to ino %llu (root %llu): %d", + handler->xattr_name, btrfs_ino(inode), + root->root_key.objectid, ret); + else + set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags); +} + +int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + u64 ino = btrfs_ino(inode); + int ret; + + ret = iterate_object_props(root, path, ino, inode_prop_iterator, inode); + + return ret; +} + +static int inherit_props(struct btrfs_trans_handle *trans, + struct inode *inode, + struct inode *parent) +{ + const struct prop_handler *h; + struct btrfs_root *root = BTRFS_I(inode)->root; + int ret; + + if (!test_bit(BTRFS_INODE_HAS_PROPS, + &BTRFS_I(parent)->runtime_flags)) + return 0; + + for (h = &prop_handlers[0]; h->xattr_name; h++) { + const char *value; + u64 num_bytes; + + if (!h->inheritable) + continue; + + value = h->extract(parent); + if (!value) + continue; + + num_bytes = btrfs_calc_trans_metadata_size(root, 1); + ret = btrfs_block_rsv_add(root, trans->block_rsv, + num_bytes, BTRFS_RESERVE_NO_FLUSH); + if (ret) + goto out; + ret = __btrfs_set_prop(trans, inode, h->xattr_name, + value, strlen(value), 0); + btrfs_block_rsv_release(root, trans->block_rsv, num_bytes); + if (ret) + goto out; + } + ret = 0; +out: + return ret; +} + +int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans, + struct inode *inode, + struct inode *dir) +{ + if (!dir) + return 0; + + return inherit_props(trans, inode, dir); +} + +int btrfs_subvol_inherit_props(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_root *parent_root) +{ + struct btrfs_key key; + struct inode *parent_inode, *child_inode; + int ret; + + key.objectid = BTRFS_FIRST_FREE_OBJECTID; + key.type = BTRFS_INODE_ITEM_KEY; + key.offset = 0; + + parent_inode = btrfs_iget(parent_root->fs_info->sb, &key, + parent_root, NULL); + if (IS_ERR(parent_inode)) + return PTR_ERR(parent_inode); + + child_inode = btrfs_iget(root->fs_info->sb, &key, root, NULL); + if (IS_ERR(child_inode)) { + iput(parent_inode); + return PTR_ERR(child_inode); + } + + ret = inherit_props(trans, child_inode, parent_inode); + iput(child_inode); + iput(parent_inode); + + return ret; +} + +static int prop_compression_validate(const char *value, size_t len) +{ + if (!strncmp("lzo", value, len)) + return 0; + else if (!strncmp("zlib", value, len)) + return 0; + + return -EINVAL; +} + +static int prop_compression_apply(struct inode *inode, + const char *value, + size_t len) +{ + int type; + + if (len == 0) { + BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS; + BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS; + BTRFS_I(inode)->force_compress = BTRFS_COMPRESS_NONE; + + return 0; + } + + if (!strncmp("lzo", value, len)) + type = BTRFS_COMPRESS_LZO; + else if (!strncmp("zlib", value, len)) + type = BTRFS_COMPRESS_ZLIB; + else + return -EINVAL; + + BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS; + BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS; + BTRFS_I(inode)->force_compress = type; + + return 0; +} + +static const char *prop_compression_extract(struct inode *inode) +{ + switch (BTRFS_I(inode)->force_compress) { + case BTRFS_COMPRESS_ZLIB: + return "zlib"; + case BTRFS_COMPRESS_LZO: + return "lzo"; + } + + return NULL; +} |