linux-stable/fs/btrfs/dir-item.c
Filipe Manana 50564b651d btrfs: abort transaction on generation mismatch when marking eb as dirty
When marking an extent buffer as dirty, at btrfs_mark_buffer_dirty(),
we check if its generation matches the running transaction and if not we
just print a warning. Such mismatch is an indicator that something really
went wrong and only printing a warning message (and stack trace) is not
enough to prevent a corruption. Allowing a transaction to commit with such
an extent buffer will trigger an error if we ever try to read it from disk
due to a generation mismatch with its parent generation.

So abort the current transaction with -EUCLEAN if we notice a generation
mismatch. For this we need to pass a transaction handle to
btrfs_mark_buffer_dirty() which is always available except in test code,
in which case we can pass NULL since it operates on dummy extent buffers
and all test roots have a single node/leaf (root node at level 0).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:07 +02:00

445 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include "messages.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "accessors.h"
#include "dir-item.h"
/*
* insert a name into a directory, doing overflow properly if there is a hash
* collision. data_size indicates how big the item inserted should be. On
* success a struct btrfs_dir_item pointer is returned, otherwise it is
* an ERR_PTR.
*
* The name is not copied into the dir item, you have to do that yourself.
*/
static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
*trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_key *cpu_key,
u32 data_size,
const char *name,
int name_len)
{
struct btrfs_fs_info *fs_info = root->fs_info;
int ret;
char *ptr;
struct extent_buffer *leaf;
ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
if (ret == -EEXIST) {
struct btrfs_dir_item *di;
di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
if (di)
return ERR_PTR(-EEXIST);
btrfs_extend_item(trans, path, data_size);
} else if (ret < 0)
return ERR_PTR(ret);
WARN_ON(ret > 0);
leaf = path->nodes[0];
ptr = btrfs_item_ptr(leaf, path->slots[0], char);
ASSERT(data_size <= btrfs_item_size(leaf, path->slots[0]));
ptr += btrfs_item_size(leaf, path->slots[0]) - data_size;
return (struct btrfs_dir_item *)ptr;
}
/*
* xattrs work a lot like directories, this inserts an xattr item
* into the tree
*/
int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 objectid,
const char *name, u16 name_len,
const void *data, u16 data_len)
{
int ret = 0;
struct btrfs_dir_item *dir_item;
unsigned long name_ptr, data_ptr;
struct btrfs_key key, location;
struct btrfs_disk_key disk_key;
struct extent_buffer *leaf;
u32 data_size;
if (name_len + data_len > BTRFS_MAX_XATTR_SIZE(root->fs_info))
return -ENOSPC;
key.objectid = objectid;
key.type = BTRFS_XATTR_ITEM_KEY;
key.offset = btrfs_name_hash(name, name_len);
data_size = sizeof(*dir_item) + name_len + data_len;
dir_item = insert_with_overflow(trans, root, path, &key, data_size,
name, name_len);
if (IS_ERR(dir_item))
return PTR_ERR(dir_item);
memset(&location, 0, sizeof(location));
leaf = path->nodes[0];
btrfs_cpu_key_to_disk(&disk_key, &location);
btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
btrfs_set_dir_flags(leaf, dir_item, BTRFS_FT_XATTR);
btrfs_set_dir_name_len(leaf, dir_item, name_len);
btrfs_set_dir_transid(leaf, dir_item, trans->transid);
btrfs_set_dir_data_len(leaf, dir_item, data_len);
name_ptr = (unsigned long)(dir_item + 1);
data_ptr = (unsigned long)((char *)name_ptr + name_len);
write_extent_buffer(leaf, name, name_ptr, name_len);
write_extent_buffer(leaf, data, data_ptr, data_len);
btrfs_mark_buffer_dirty(trans, path->nodes[0]);
return ret;
}
/*
* insert a directory item in the tree, doing all the magic for
* both indexes. 'dir' indicates which objectid to insert it into,
* 'location' is the key to stuff into the directory item, 'type' is the
* type of the inode we're pointing to, and 'index' is the sequence number
* to use for the second index (if one is created).
* Will return 0 or -ENOMEM
*/
int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,
const struct fscrypt_str *name, struct btrfs_inode *dir,
struct btrfs_key *location, u8 type, u64 index)
{
int ret = 0;
int ret2 = 0;
struct btrfs_root *root = dir->root;
struct btrfs_path *path;
struct btrfs_dir_item *dir_item;
struct extent_buffer *leaf;
unsigned long name_ptr;
struct btrfs_key key;
struct btrfs_disk_key disk_key;
u32 data_size;
key.objectid = btrfs_ino(dir);
key.type = BTRFS_DIR_ITEM_KEY;
key.offset = btrfs_name_hash(name->name, name->len);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
btrfs_cpu_key_to_disk(&disk_key, location);
data_size = sizeof(*dir_item) + name->len;
dir_item = insert_with_overflow(trans, root, path, &key, data_size,
name->name, name->len);
if (IS_ERR(dir_item)) {
ret = PTR_ERR(dir_item);
if (ret == -EEXIST)
goto second_insert;
goto out_free;
}
if (IS_ENCRYPTED(&dir->vfs_inode))
type |= BTRFS_FT_ENCRYPTED;
leaf = path->nodes[0];
btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
btrfs_set_dir_flags(leaf, dir_item, type);
btrfs_set_dir_data_len(leaf, dir_item, 0);
btrfs_set_dir_name_len(leaf, dir_item, name->len);
btrfs_set_dir_transid(leaf, dir_item, trans->transid);
name_ptr = (unsigned long)(dir_item + 1);
write_extent_buffer(leaf, name->name, name_ptr, name->len);
btrfs_mark_buffer_dirty(trans, leaf);
second_insert:
/* FIXME, use some real flag for selecting the extra index */
if (root == root->fs_info->tree_root) {
ret = 0;
goto out_free;
}
btrfs_release_path(path);
ret2 = btrfs_insert_delayed_dir_index(trans, name->name, name->len, dir,
&disk_key, type, index);
out_free:
btrfs_free_path(path);
if (ret)
return ret;
if (ret2)
return ret2;
return 0;
}
static struct btrfs_dir_item *btrfs_lookup_match_dir(
struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_key *key, const char *name,
int name_len, int mod)
{
const int ins_len = (mod < 0 ? -1 : 0);
const int cow = (mod != 0);
int ret;
ret = btrfs_search_slot(trans, root, key, path, ins_len, cow);
if (ret < 0)
return ERR_PTR(ret);
if (ret > 0)
return ERR_PTR(-ENOENT);
return btrfs_match_dir_item_name(root->fs_info, path, name, name_len);
}
/*
* Lookup for a directory item by name.
*
* @trans: The transaction handle to use. Can be NULL if @mod is 0.
* @root: The root of the target tree.
* @path: Path to use for the search.
* @dir: The inode number (objectid) of the directory.
* @name: The name associated to the directory entry we are looking for.
* @name_len: The length of the name.
* @mod: Used to indicate if the tree search is meant for a read only
* lookup, for a modification lookup or for a deletion lookup, so
* its value should be 0, 1 or -1, respectively.
*
* Returns: NULL if the dir item does not exists, an error pointer if an error
* happened, or a pointer to a dir item if a dir item exists for the given name.
*/
struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 dir,
const struct fscrypt_str *name,
int mod)
{
struct btrfs_key key;
struct btrfs_dir_item *di;
key.objectid = dir;
key.type = BTRFS_DIR_ITEM_KEY;
key.offset = btrfs_name_hash(name->name, name->len);
di = btrfs_lookup_match_dir(trans, root, path, &key, name->name,
name->len, mod);
if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
return NULL;
return di;
}
int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
const struct fscrypt_str *name)
{
int ret;
struct btrfs_key key;
struct btrfs_dir_item *di;
int data_size;
struct extent_buffer *leaf;
int slot;
struct btrfs_path *path;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = dir;
key.type = BTRFS_DIR_ITEM_KEY;
key.offset = btrfs_name_hash(name->name, name->len);
di = btrfs_lookup_match_dir(NULL, root, path, &key, name->name,
name->len, 0);
if (IS_ERR(di)) {
ret = PTR_ERR(di);
/* Nothing found, we're safe */
if (ret == -ENOENT) {
ret = 0;
goto out;
}
if (ret < 0)
goto out;
}
/* we found an item, look for our name in the item */
if (di) {
/* our exact name was found */
ret = -EEXIST;
goto out;
}
/* See if there is room in the item to insert this name. */
data_size = sizeof(*di) + name->len;
leaf = path->nodes[0];
slot = path->slots[0];
if (data_size + btrfs_item_size(leaf, slot) +
sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
ret = -EOVERFLOW;
} else {
/* plenty of insertion room */
ret = 0;
}
out:
btrfs_free_path(path);
return ret;
}
/*
* Lookup for a directory index item by name and index number.
*
* @trans: The transaction handle to use. Can be NULL if @mod is 0.
* @root: The root of the target tree.
* @path: Path to use for the search.
* @dir: The inode number (objectid) of the directory.
* @index: The index number.
* @name: The name associated to the directory entry we are looking for.
* @name_len: The length of the name.
* @mod: Used to indicate if the tree search is meant for a read only
* lookup, for a modification lookup or for a deletion lookup, so
* its value should be 0, 1 or -1, respectively.
*
* Returns: NULL if the dir index item does not exists, an error pointer if an
* error happened, or a pointer to a dir item if the dir index item exists and
* matches the criteria (name and index number).
*/
struct btrfs_dir_item *
btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 dir,
u64 index, const struct fscrypt_str *name, int mod)
{
struct btrfs_dir_item *di;
struct btrfs_key key;
key.objectid = dir;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = index;
di = btrfs_lookup_match_dir(trans, root, path, &key, name->name,
name->len, mod);
if (di == ERR_PTR(-ENOENT))
return NULL;
return di;
}
struct btrfs_dir_item *
btrfs_search_dir_index_item(struct btrfs_root *root, struct btrfs_path *path,
u64 dirid, const struct fscrypt_str *name)
{
struct btrfs_dir_item *di;
struct btrfs_key key;
int ret;
key.objectid = dirid;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = 0;
btrfs_for_each_slot(root, &key, &key, path, ret) {
if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
break;
di = btrfs_match_dir_item_name(root->fs_info, path,
name->name, name->len);
if (di)
return di;
}
/* Adjust return code if the key was not found in the next leaf. */
if (ret > 0)
ret = 0;
return ERR_PTR(ret);
}
struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 dir,
const char *name, u16 name_len,
int mod)
{
struct btrfs_key key;
struct btrfs_dir_item *di;
key.objectid = dir;
key.type = BTRFS_XATTR_ITEM_KEY;
key.offset = btrfs_name_hash(name, name_len);
di = btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
return NULL;
return di;
}
/*
* helper function to look at the directory item pointed to by 'path'
* this walks through all the entries in a dir item and finds one
* for a specific name.
*/
struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_fs_info *fs_info,
struct btrfs_path *path,
const char *name, int name_len)
{
struct btrfs_dir_item *dir_item;
unsigned long name_ptr;
u32 total_len;
u32 cur = 0;
u32 this_len;
struct extent_buffer *leaf;
leaf = path->nodes[0];
dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
total_len = btrfs_item_size(leaf, path->slots[0]);
while (cur < total_len) {
this_len = sizeof(*dir_item) +
btrfs_dir_name_len(leaf, dir_item) +
btrfs_dir_data_len(leaf, dir_item);
name_ptr = (unsigned long)(dir_item + 1);
if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
return dir_item;
cur += this_len;
dir_item = (struct btrfs_dir_item *)((char *)dir_item +
this_len);
}
return NULL;
}
/*
* given a pointer into a directory item, delete it. This
* handles items that have more than one entry in them.
*/
int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_dir_item *di)
{
struct extent_buffer *leaf;
u32 sub_item_len;
u32 item_len;
int ret = 0;
leaf = path->nodes[0];
sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
btrfs_dir_data_len(leaf, di);
item_len = btrfs_item_size(leaf, path->slots[0]);
if (sub_item_len == item_len) {
ret = btrfs_del_item(trans, root, path);
} else {
/* MARKER */
unsigned long ptr = (unsigned long)di;
unsigned long start;
start = btrfs_item_ptr_offset(leaf, path->slots[0]);
memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
item_len - (ptr + sub_item_len - start));
btrfs_truncate_item(trans, path, item_len - sub_item_len, 1);
}
return ret;
}