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// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "bkey_methods.h"
#include "btree_update.h"
#include "extents.h"
#include "dirent.h"
#include "fs.h"
#include "keylist.h"
#include "str_hash.h"
#include <linux/dcache.h>
unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent d)
{
unsigned len = bkey_val_bytes(d.k) -
offsetof(struct bch_dirent, d_name);
return strnlen(d.v->d_name, len);
}
static u64 bch2_dirent_hash(const struct bch_hash_info *info,
const struct qstr *name)
{
struct bch_str_hash_ctx ctx;
bch2_str_hash_init(&ctx, info);
bch2_str_hash_update(&ctx, info, name->name, name->len);
/* [0,2) reserved for dots */
return max_t(u64, bch2_str_hash_end(&ctx, info), 2);
}
static u64 dirent_hash_key(const struct bch_hash_info *info, const void *key)
{
return bch2_dirent_hash(info, key);
}
static u64 dirent_hash_bkey(const struct bch_hash_info *info, struct bkey_s_c k)
{
struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
struct qstr name = QSTR_INIT(d.v->d_name, bch2_dirent_name_bytes(d));
return bch2_dirent_hash(info, &name);
}
static bool dirent_cmp_key(struct bkey_s_c _l, const void *_r)
{
struct bkey_s_c_dirent l = bkey_s_c_to_dirent(_l);
int len = bch2_dirent_name_bytes(l);
const struct qstr *r = _r;
return len - r->len ?: memcmp(l.v->d_name, r->name, len);
}
static bool dirent_cmp_bkey(struct bkey_s_c _l, struct bkey_s_c _r)
{
struct bkey_s_c_dirent l = bkey_s_c_to_dirent(_l);
struct bkey_s_c_dirent r = bkey_s_c_to_dirent(_r);
int l_len = bch2_dirent_name_bytes(l);
int r_len = bch2_dirent_name_bytes(r);
return l_len - r_len ?: memcmp(l.v->d_name, r.v->d_name, l_len);
}
const struct bch_hash_desc bch2_dirent_hash_desc = {
.btree_id = BTREE_ID_DIRENTS,
.key_type = BCH_DIRENT,
.whiteout_type = BCH_DIRENT_WHITEOUT,
.hash_key = dirent_hash_key,
.hash_bkey = dirent_hash_bkey,
.cmp_key = dirent_cmp_key,
.cmp_bkey = dirent_cmp_bkey,
};
const char *bch2_dirent_invalid(const struct bch_fs *c, struct bkey_s_c k)
{
struct bkey_s_c_dirent d;
unsigned len;
switch (k.k->type) {
case BCH_DIRENT:
if (bkey_val_bytes(k.k) < sizeof(struct bch_dirent))
return "value too small";
d = bkey_s_c_to_dirent(k);
len = bch2_dirent_name_bytes(d);
if (!len)
return "empty name";
/*
* older versions of bcachefs were buggy and creating dirent
* keys that were bigger than necessary:
*/
if (bkey_val_u64s(k.k) > dirent_val_u64s(len + 7))
return "value too big";
if (len > BCH_NAME_MAX)
return "dirent name too big";
return NULL;
case BCH_DIRENT_WHITEOUT:
return bkey_val_bytes(k.k) != 0
? "value size should be zero"
: NULL;
default:
return "invalid type";
}
}
void bch2_dirent_to_text(struct printbuf *out, struct bch_fs *c,
struct bkey_s_c k)
{
struct bkey_s_c_dirent d;
switch (k.k->type) {
case BCH_DIRENT:
d = bkey_s_c_to_dirent(k);
bch_scnmemcpy(out, d.v->d_name,
bch2_dirent_name_bytes(d));
pr_buf(out, " -> %llu", d.v->d_inum);
break;
case BCH_DIRENT_WHITEOUT:
pr_buf(out, "whiteout");
break;
}
}
static struct bkey_i_dirent *dirent_create_key(struct btree_trans *trans,
u8 type, const struct qstr *name, u64 dst)
{
struct bkey_i_dirent *dirent;
unsigned u64s = BKEY_U64s + dirent_val_u64s(name->len);
if (name->len > BCH_NAME_MAX)
return ERR_PTR(-ENAMETOOLONG);
BUG_ON(u64s > U8_MAX);
dirent = bch2_trans_kmalloc(trans, u64s * sizeof(u64));
if (IS_ERR(dirent))
return dirent;
bkey_dirent_init(&dirent->k_i);
dirent->k.u64s = u64s;
dirent->v.d_inum = cpu_to_le64(dst);
dirent->v.d_type = type;
memcpy(dirent->v.d_name, name->name, name->len);
memset(dirent->v.d_name + name->len, 0,
bkey_val_bytes(&dirent->k) -
offsetof(struct bch_dirent, d_name) -
name->len);
EBUG_ON(bch2_dirent_name_bytes(dirent_i_to_s_c(dirent)) != name->len);
return dirent;
}
int __bch2_dirent_create(struct btree_trans *trans,
u64 dir_inum, const struct bch_hash_info *hash_info,
u8 type, const struct qstr *name, u64 dst_inum,
int flags)
{
struct bkey_i_dirent *dirent;
int ret;
dirent = dirent_create_key(trans, type, name, dst_inum);
ret = PTR_ERR_OR_ZERO(dirent);
if (ret)
return ret;
return __bch2_hash_set(trans, bch2_dirent_hash_desc, hash_info,
dir_inum, &dirent->k_i, flags);
}
int bch2_dirent_create(struct bch_fs *c, u64 dir_inum,
const struct bch_hash_info *hash_info,
u8 type, const struct qstr *name, u64 dst_inum,
u64 *journal_seq, int flags)
{
return bch2_trans_do(c, journal_seq, flags,
__bch2_dirent_create(&trans, dir_inum, hash_info,
type, name, dst_inum, flags));
}
static void dirent_copy_target(struct bkey_i_dirent *dst,
struct bkey_s_c_dirent src)
{
dst->v.d_inum = src.v->d_inum;
dst->v.d_type = src.v->d_type;
}
static struct bpos bch2_dirent_pos(struct bch_inode_info *inode,
const struct qstr *name)
{
return POS(inode->v.i_ino, bch2_dirent_hash(&inode->ei_str_hash, name));
}
int bch2_dirent_rename(struct btree_trans *trans,
struct bch_inode_info *src_dir, const struct qstr *src_name,
struct bch_inode_info *dst_dir, const struct qstr *dst_name,
enum bch_rename_mode mode)
{
struct btree_iter *src_iter, *dst_iter;
struct bkey_s_c old_src, old_dst;
struct bkey_i_dirent *new_src = NULL, *new_dst = NULL;
struct bpos dst_pos = bch2_dirent_pos(dst_dir, dst_name);
int ret;
/*
* Lookup dst:
*
* Note that in BCH_RENAME mode, we're _not_ checking if
* the target already exists - we're relying on the VFS
* to do that check for us for correctness:
*/
dst_iter = mode == BCH_RENAME
? bch2_hash_hole(trans, bch2_dirent_hash_desc,
&dst_dir->ei_str_hash,
dst_dir->v.i_ino, dst_name)
: bch2_hash_lookup(trans, bch2_dirent_hash_desc,
&dst_dir->ei_str_hash,
dst_dir->v.i_ino, dst_name,
BTREE_ITER_INTENT);
if (IS_ERR(dst_iter))
return PTR_ERR(dst_iter);
old_dst = bch2_btree_iter_peek_slot(dst_iter);
/* Lookup src: */
src_iter = bch2_hash_lookup(trans, bch2_dirent_hash_desc,
&src_dir->ei_str_hash,
src_dir->v.i_ino, src_name,
BTREE_ITER_INTENT);
if (IS_ERR(src_iter))
return PTR_ERR(src_iter);
old_src = bch2_btree_iter_peek_slot(src_iter);
/* Create new dst key: */
new_dst = dirent_create_key(trans, 0, dst_name, 0);
if (IS_ERR(new_dst))
return PTR_ERR(new_dst);
dirent_copy_target(new_dst, bkey_s_c_to_dirent(old_src));
new_dst->k.p = dst_iter->pos;
/* Create new src key: */
if (mode == BCH_RENAME_EXCHANGE) {
new_src = dirent_create_key(trans, 0, src_name, 0);
if (IS_ERR(new_src))
return PTR_ERR(new_src);
dirent_copy_target(new_src, bkey_s_c_to_dirent(old_dst));
new_src->k.p = src_iter->pos;
} else {
new_src = bch2_trans_kmalloc(trans, sizeof(struct bkey_i));
if (IS_ERR(new_src))
return PTR_ERR(new_src);
bkey_init(&new_src->k);
new_src->k.p = src_iter->pos;
if (bkey_cmp(dst_pos, src_iter->pos) <= 0 &&
bkey_cmp(src_iter->pos, dst_iter->pos) < 0) {
/*
* We have a hash collision for the new dst key,
* and new_src - the key we're deleting - is between
* new_dst's hashed slot and the slot we're going to be
* inserting it into - oops. This will break the hash
* table if we don't deal with it:
*/
if (mode == BCH_RENAME) {
/*
* If we're not overwriting, we can just insert
* new_dst at the src position:
*/
new_dst->k.p = src_iter->pos;
bch2_trans_update(trans,
BTREE_INSERT_ENTRY(src_iter,
&new_dst->k_i));
return 0;
} else {
/* If we're overwriting, we can't insert new_dst
* at a different slot because it has to
* overwrite old_dst - just make sure to use a
* whiteout when deleting src:
*/
new_src->k.type = BCH_DIRENT_WHITEOUT;
}
} else {
/* Check if we need a whiteout to delete src: */
ret = bch2_hash_needs_whiteout(trans, bch2_dirent_hash_desc,
&src_dir->ei_str_hash,
src_iter);
if (ret < 0)
return ret;
if (ret)
new_src->k.type = BCH_DIRENT_WHITEOUT;
}
}
bch2_trans_update(trans, BTREE_INSERT_ENTRY(src_iter, &new_src->k_i));
bch2_trans_update(trans, BTREE_INSERT_ENTRY(dst_iter, &new_dst->k_i));
return 0;
}
int __bch2_dirent_delete(struct btree_trans *trans, u64 dir_inum,
const struct bch_hash_info *hash_info,
const struct qstr *name)
{
return bch2_hash_delete(trans, bch2_dirent_hash_desc, hash_info,
dir_inum, name);
}
int bch2_dirent_delete(struct bch_fs *c, u64 dir_inum,
const struct bch_hash_info *hash_info,
const struct qstr *name,
u64 *journal_seq)
{
return bch2_trans_do(c, journal_seq,
BTREE_INSERT_ATOMIC|
BTREE_INSERT_NOFAIL,
__bch2_dirent_delete(&trans, dir_inum, hash_info, name));
}
u64 bch2_dirent_lookup(struct bch_fs *c, u64 dir_inum,
const struct bch_hash_info *hash_info,
const struct qstr *name)
{
struct btree_trans trans;
struct btree_iter *iter;
struct bkey_s_c k;
u64 inum = 0;
bch2_trans_init(&trans, c);
iter = bch2_hash_lookup(&trans, bch2_dirent_hash_desc,
hash_info, dir_inum, name, 0);
if (IS_ERR(iter)) {
BUG_ON(PTR_ERR(iter) == -EINTR);
goto out;
}
k = bch2_btree_iter_peek_slot(iter);
inum = le64_to_cpu(bkey_s_c_to_dirent(k).v->d_inum);
out:
bch2_trans_exit(&trans);
return inum;
}
int bch2_empty_dir(struct bch_fs *c, u64 dir_inum)
{
struct btree_iter iter;
struct bkey_s_c k;
int ret = 0;
for_each_btree_key(&iter, c, BTREE_ID_DIRENTS, POS(dir_inum, 0), 0, k) {
if (k.k->p.inode > dir_inum)
break;
if (k.k->type == BCH_DIRENT) {
ret = -ENOTEMPTY;
break;
}
}
bch2_btree_iter_unlock(&iter);
return ret;
}
int bch2_readdir(struct bch_fs *c, struct file *file,
struct dir_context *ctx)
{
struct bch_inode_info *inode = file_bch_inode(file);
struct btree_iter iter;
struct bkey_s_c k;
struct bkey_s_c_dirent dirent;
unsigned len;
if (!dir_emit_dots(file, ctx))
return 0;
for_each_btree_key(&iter, c, BTREE_ID_DIRENTS,
POS(inode->v.i_ino, ctx->pos), 0, k) {
if (k.k->type != BCH_DIRENT)
continue;
dirent = bkey_s_c_to_dirent(k);
if (bkey_cmp(k.k->p, POS(inode->v.i_ino, ctx->pos)) < 0)
continue;
if (k.k->p.inode > inode->v.i_ino)
break;
len = bch2_dirent_name_bytes(dirent);
/*
* XXX: dir_emit() can fault and block, while we're holding
* locks
*/
if (!dir_emit(ctx, dirent.v->d_name, len,
le64_to_cpu(dirent.v->d_inum),
dirent.v->d_type))
break;
ctx->pos = k.k->p.offset + 1;
}
bch2_btree_iter_unlock(&iter);
return 0;
}
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