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