// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "bkey_buf.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 "subvolume.h"
#include <linux/dcache.h>
static unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent d)
{
if (bkey_val_bytes(d.k) < offsetof(struct bch_dirent, d_name))
return 0;
unsigned bkey_u64s = bkey_val_u64s(d.k);
unsigned bkey_bytes = bkey_u64s * sizeof(u64);
u64 last_u64 = ((u64*)d.v)[bkey_u64s - 1];
#if CPU_BIG_ENDIAN
unsigned trailing_nuls = last_u64 ? __builtin_ctzll(last_u64) / 8 : 64 / 8;
#else
unsigned trailing_nuls = last_u64 ? __builtin_clzll(last_u64) / 8 : 64 / 8;
#endif
return bkey_bytes -
offsetof(struct bch_dirent, d_name) -
trailing_nuls;
}
struct qstr bch2_dirent_get_name(struct bkey_s_c_dirent d)
{
return (struct qstr) QSTR_INIT(d.v->d_name, bch2_dirent_name_bytes(d));
}
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 = bch2_dirent_get_name(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);
const struct qstr l_name = bch2_dirent_get_name(l);
const struct qstr *r_name = _r;
return !qstr_eq(l_name, *r_name);
}
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);
const struct qstr l_name = bch2_dirent_get_name(l);
const struct qstr r_name = bch2_dirent_get_name(r);
return !qstr_eq(l_name, r_name);
}
static bool dirent_is_visible(subvol_inum inum, struct bkey_s_c k)
{
struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
if (d.v->d_type == DT_SUBVOL)
return le32_to_cpu(d.v->d_parent_subvol) == inum.subvol;
return true;
}
const struct bch_hash_desc bch2_dirent_hash_desc = {
.btree_id = BTREE_ID_dirents,
.key_type = KEY_TYPE_dirent,
.hash_key = dirent_hash_key,
.hash_bkey = dirent_hash_bkey,
.cmp_key = dirent_cmp_key,
.cmp_bkey = dirent_cmp_bkey,
.is_visible = dirent_is_visible,
};
int bch2_dirent_validate(struct bch_fs *c, struct bkey_s_c k,
enum bch_validate_flags flags)
{
struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
struct qstr d_name = bch2_dirent_get_name(d);
int ret = 0;
bkey_fsck_err_on(!d_name.len,
c, dirent_empty_name,
"empty name");
bkey_fsck_err_on(bkey_val_u64s(k.k) > dirent_val_u64s(d_name.len),
c, dirent_val_too_big,
"value too big (%zu > %u)",
bkey_val_u64s(k.k), dirent_val_u64s(d_name.len));
/*
* Check new keys don't exceed the max length
* (older keys may be larger.)
*/
bkey_fsck_err_on((flags & BCH_VALIDATE_commit) && d_name.len > BCH_NAME_MAX,
c, dirent_name_too_long,
"dirent name too big (%u > %u)",
d_name.len, BCH_NAME_MAX);
bkey_fsck_err_on(d_name.len != strnlen(d_name.name, d_name.len),
c, dirent_name_embedded_nul,
"dirent has stray data after name's NUL");
bkey_fsck_err_on((d_name.len == 1 && !memcmp(d_name.name, ".", 1)) ||
(d_name.len == 2 && !memcmp(d_name.name, "..", 2)),
c, dirent_name_dot_or_dotdot,
"invalid name");
bkey_fsck_err_on(memchr(d_name.name, '/', d_name.len),
c, dirent_name_has_slash,
"name with /");
bkey_fsck_err_on(d.v->d_type != DT_SUBVOL &&
le64_to_cpu(d.v->d_inum) == d.k->p.inode,
c, dirent_to_itself,
"dirent points to own directory");
fsck_err:
return ret;
}
void bch2_dirent_to_text(struct printbuf *out, struct bch_fs *c, struct bkey_s_c k)
{
struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
struct qstr d_name = bch2_dirent_get_name(d);
prt_printf(out, "%.*s -> ", d_name.len, d_name.name);
if (d.v->d_type != DT_SUBVOL)
prt_printf(out, "%llu", le64_to_cpu(d.v->d_inum));
else
prt_printf(out, "%u -> %u",
le32_to_cpu(d.v->d_parent_subvol),
le32_to_cpu(d.v->d_child_subvol));
prt_printf(out, " type %s", bch2_d_type_str(d.v->d_type));
}
static struct bkey_i_dirent *dirent_create_key(struct btree_trans *trans,
subvol_inum dir, 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;
if (type != DT_SUBVOL) {
dirent->v.d_inum = cpu_to_le64(dst);
} else {
dirent->v.d_parent_subvol = cpu_to_le32(dir.subvol);
dirent->v.d_child_subvol = cpu_to_le32(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_snapshot(struct btree_trans *trans,
u32 dir_subvol, u64 dir, u32 snapshot,
const struct bch_hash_info *hash_info,
u8 type, const struct qstr *name, u64 dst_inum,
u64 *dir_offset,
enum btree_iter_update_trigger_flags flags)
{
subvol_inum dir_inum = { .subvol = dir_subvol, .inum = dir };
struct bkey_i_dirent *dirent;
int ret;
dirent = dirent_create_key(trans, dir_inum, type, name, dst_inum);
ret = PTR_ERR_OR_ZERO(dirent);
if (ret)
return ret;
dirent->k.p.inode = dir;
dirent->k.p.snapshot = snapshot;
ret = bch2_hash_set_in_snapshot(trans, bch2_dirent_hash_desc, hash_info,
dir_inum, snapshot, &dirent->k_i,
flags|BTREE_UPDATE_internal_snapshot_node);
*dir_offset = dirent->k.p.offset;
return ret;
}
int bch2_dirent_create(struct btree_trans *trans, subvol_inum dir,
const struct bch_hash_info *hash_info,
u8 type, const struct qstr *name, u64 dst_inum,
u64 *dir_offset,
enum btree_iter_update_trigger_flags flags)
{
struct bkey_i_dirent *dirent;
int ret;
dirent = dirent_create_key(trans, dir, type, name, dst_inum);
ret = PTR_ERR_OR_ZERO(dirent);
if (ret)
return ret;
ret = bch2_hash_set(trans, bch2_dirent_hash_desc, hash_info,
dir, &dirent->k_i, flags);
*dir_offset = dirent->k.p.offset;
return ret;
}
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;
}
int bch2_dirent_read_target(struct btree_trans *trans, subvol_inum dir,
struct bkey_s_c_dirent d, subvol_inum *target)
{
struct bch_subvolume s;
int ret = 0;
if (d.v->d_type == DT_SUBVOL &&
le32_to_cpu(d.v->d_parent_subvol) != dir.subvol)
return 1;
if (likely(d.v->d_type != DT_SUBVOL)) {
target->subvol = dir.subvol;
target->inum = le64_to_cpu(d.v->d_inum);
} else {
target->subvol = le32_to_cpu(d.v->d_child_subvol);
ret = bch2_subvolume_get(trans, target->subvol, true, BTREE_ITER_cached, &s);
target->inum = le64_to_cpu(s.inode);
}
return ret;
}
int bch2_dirent_rename(struct btree_trans *trans,
subvol_inum src_dir, struct bch_hash_info *src_hash,
subvol_inum dst_dir, struct bch_hash_info *dst_hash,
const struct qstr *src_name, subvol_inum *src_inum, u64 *src_offset,
const struct qstr *dst_name, subvol_inum *dst_inum, u64 *dst_offset,
enum bch_rename_mode mode)
{
struct btree_iter src_iter = { NULL };
struct btree_iter dst_iter = { NULL };
struct bkey_s_c old_src, old_dst = bkey_s_c_null;
struct bkey_i_dirent *new_src = NULL, *new_dst = NULL;
struct bpos dst_pos =
POS(dst_dir.inum, bch2_dirent_hash(dst_hash, dst_name));
unsigned src_update_flags = 0;
bool delete_src, delete_dst;
int ret = 0;
memset(src_inum, 0, sizeof(*src_inum));
memset(dst_inum, 0, sizeof(*dst_inum));
/* Lookup src: */
old_src = bch2_hash_lookup(trans, &src_iter, bch2_dirent_hash_desc,
src_hash, src_dir, src_name,
BTREE_ITER_intent);
ret = bkey_err(old_src);
if (ret)
goto out;
ret = bch2_dirent_read_target(trans, src_dir,
bkey_s_c_to_dirent(old_src), src_inum);
if (ret)
goto out;
/* Lookup dst: */
if (mode == BCH_RENAME) {
/*
* Note that we're _not_ checking if the target already exists -
* we're relying on the VFS to do that check for us for
* correctness:
*/
ret = bch2_hash_hole(trans, &dst_iter, bch2_dirent_hash_desc,
dst_hash, dst_dir, dst_name);
if (ret)
goto out;
} else {
old_dst = bch2_hash_lookup(trans, &dst_iter, bch2_dirent_hash_desc,
dst_hash, dst_dir, dst_name,
BTREE_ITER_intent);
ret = bkey_err(old_dst);
if (ret)
goto out;
ret = bch2_dirent_read_target(trans, dst_dir,
bkey_s_c_to_dirent(old_dst), dst_inum);
if (ret)
goto out;
}
if (mode != BCH_RENAME_EXCHANGE)
*src_offset = dst_iter.pos.offset;
/* Create new dst key: */
new_dst = dirent_create_key(trans, dst_dir, 0, dst_name, 0);
ret = PTR_ERR_OR_ZERO(new_dst);
if (ret)
goto out;
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, src_dir, 0, src_name, 0);
ret = PTR_ERR_OR_ZERO(new_src);
if (ret)
goto out;
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));
ret = PTR_ERR_OR_ZERO(new_src);
if (ret)
goto out;
bkey_init(&new_src->k);
new_src->k.p = src_iter.pos;
if (bkey_le(dst_pos, src_iter.pos) &&
bkey_lt(src_iter.pos, dst_iter.pos)) {
/*
* 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_src = new_dst;
new_src->k.p = src_iter.pos;
goto out_set_src;
} 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 = KEY_TYPE_hash_whiteout;
}
} else {
/* Check if we need a whiteout to delete src: */
ret = bch2_hash_needs_whiteout(trans, bch2_dirent_hash_desc,
src_hash, &src_iter);
if (ret < 0)
goto out;
if (ret)
new_src->k.type = KEY_TYPE_hash_whiteout;
}
}
if (new_dst->v.d_type == DT_SUBVOL)
new_dst->v.d_parent_subvol = cpu_to_le32(dst_dir.subvol);
if ((mode == BCH_RENAME_EXCHANGE) &&
new_src->v.d_type == DT_SUBVOL)
new_src->v.d_parent_subvol = cpu_to_le32(src_dir.subvol);
ret = bch2_trans_update(trans, &dst_iter, &new_dst->k_i, 0);
if (ret)
goto out;
out_set_src:
/*
* If we're deleting a subvolume we need to really delete the dirent,
* not just emit a whiteout in the current snapshot - there can only be
* single dirent that points to a given subvolume.
*
* IOW, we don't maintain multiple versions in different snapshots of
* dirents that point to subvolumes - dirents that point to subvolumes
* are only visible in one particular subvolume so it's not necessary,
* and it would be particularly confusing for fsck to have to deal with.
*/
delete_src = bkey_s_c_to_dirent(old_src).v->d_type == DT_SUBVOL &&
new_src->k.p.snapshot != old_src.k->p.snapshot;
delete_dst = old_dst.k &&
bkey_s_c_to_dirent(old_dst).v->d_type == DT_SUBVOL &&
new_dst->k.p.snapshot != old_dst.k->p.snapshot;
if (!delete_src || !bkey_deleted(&new_src->k)) {
ret = bch2_trans_update(trans, &src_iter, &new_src->k_i, src_update_flags);
if (ret)
goto out;
}
if (delete_src) {
bch2_btree_iter_set_snapshot(&src_iter, old_src.k->p.snapshot);
ret = bch2_btree_iter_traverse(&src_iter) ?:
bch2_btree_delete_at(trans, &src_iter, BTREE_UPDATE_internal_snapshot_node);
if (ret)
goto out;
}
if (delete_dst) {
bch2_btree_iter_set_snapshot(&dst_iter, old_dst.k->p.snapshot);
ret = bch2_btree_iter_traverse(&dst_iter) ?:
bch2_btree_delete_at(trans, &dst_iter, BTREE_UPDATE_internal_snapshot_node);
if (ret)
goto out;
}
if (mode == BCH_RENAME_EXCHANGE)
*src_offset = new_src->k.p.offset;
*dst_offset = new_dst->k.p.offset;
out:
bch2_trans_iter_exit(trans, &src_iter);
bch2_trans_iter_exit(trans, &dst_iter);
return ret;
}
int bch2_dirent_lookup_trans(struct btree_trans *trans,
struct btree_iter *iter,
subvol_inum dir,
const struct bch_hash_info *hash_info,
const struct qstr *name, subvol_inum *inum,
unsigned flags)
{
struct bkey_s_c k = bch2_hash_lookup(trans, iter, bch2_dirent_hash_desc,
hash_info, dir, name, flags);
int ret = bkey_err(k);
if (ret)
goto err;
ret = bch2_dirent_read_target(trans, dir, bkey_s_c_to_dirent(k), inum);
if (ret > 0)
ret = -ENOENT;
err:
if (ret)
bch2_trans_iter_exit(trans, iter);
return ret;
}
u64 bch2_dirent_lookup(struct bch_fs *c, subvol_inum dir,
const struct bch_hash_info *hash_info,
const struct qstr *name, subvol_inum *inum)
{
struct btree_trans *trans = bch2_trans_get(c);
struct btree_iter iter = { NULL };
int ret = lockrestart_do(trans,
bch2_dirent_lookup_trans(trans, &iter, dir, hash_info, name, inum, 0));
bch2_trans_iter_exit(trans, &iter);
bch2_trans_put(trans);
return ret;
}
int bch2_empty_dir_snapshot(struct btree_trans *trans, u64 dir, u32 subvol, u32 snapshot)
{
struct btree_iter iter;
struct bkey_s_c k;
int ret;
for_each_btree_key_upto_norestart(trans, iter, BTREE_ID_dirents,
SPOS(dir, 0, snapshot),
POS(dir, U64_MAX), 0, k, ret)
if (k.k->type == KEY_TYPE_dirent) {
struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
if (d.v->d_type == DT_SUBVOL && le32_to_cpu(d.v->d_parent_subvol) != subvol)
continue;
ret = -BCH_ERR_ENOTEMPTY_dir_not_empty;
break;
}
bch2_trans_iter_exit(trans, &iter);
return ret;
}
int bch2_empty_dir_trans(struct btree_trans *trans, subvol_inum dir)
{
u32 snapshot;
return bch2_subvolume_get_snapshot(trans, dir.subvol, &snapshot) ?:
bch2_empty_dir_snapshot(trans, dir.inum, dir.subvol, snapshot);
}
static int bch2_dir_emit(struct dir_context *ctx, struct bkey_s_c_dirent d, subvol_inum target)
{
struct qstr name = bch2_dirent_get_name(d);
/*
* Although not required by the kernel code, updating ctx->pos is needed
* for the bcachefs FUSE driver. Without this update, the FUSE
* implementation will be stuck in an infinite loop when reading
* directories (via the bcachefs_fuse_readdir callback).
* In kernel space, ctx->pos is updated by the VFS code.
*/
ctx->pos = d.k->p.offset;
bool ret = dir_emit(ctx, name.name,
name.len,
target.inum,
vfs_d_type(d.v->d_type));
if (ret)
ctx->pos = d.k->p.offset + 1;
return ret;
}
int bch2_readdir(struct bch_fs *c, subvol_inum inum, struct dir_context *ctx)
{
struct bkey_buf sk;
bch2_bkey_buf_init(&sk);
int ret = bch2_trans_run(c,
for_each_btree_key_in_subvolume_upto(trans, iter, BTREE_ID_dirents,
POS(inum.inum, ctx->pos),
POS(inum.inum, U64_MAX),
inum.subvol, 0, k, ({
if (k.k->type != KEY_TYPE_dirent)
continue;
/* dir_emit() can fault and block: */
bch2_bkey_buf_reassemble(&sk, c, k);
struct bkey_s_c_dirent dirent = bkey_i_to_s_c_dirent(sk.k);
subvol_inum target;
int ret2 = bch2_dirent_read_target(trans, inum, dirent, &target);
if (ret2 > 0)
continue;
ret2 ?: drop_locks_do(trans, bch2_dir_emit(ctx, dirent, target));
})));
bch2_bkey_buf_exit(&sk, c);
return ret < 0 ? ret : 0;
}
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