linux/fs/btrfs/props.c
David Sterba e8c9f18603 btrfs: constify structs with op functions or static definitions
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>
2015-02-16 18:48:44 +01:00

430 lines
9.7 KiB
C

/*
* 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;
}