1

bcachefs: Use KEY_TYPE_deleted whitouts for extents

Previously, partial overwrites of existing extents were handled
implicitly by the btree code; when reading in a btree node, we'd do a
mergesort of the different bsets and detect and fix partially
overlapping extents during that mergesort.

That approach won't work with snapshots: this changes extents to work
like regular keys as far as the btree code is concerned, where a 0 size
KEY_TYPE_deleted whiteout will completely overwrite an existing extent.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2019-11-26 17:26:04 -05:00 committed by Kent Overstreet
parent 1c3ff72c0f
commit bcd6f3e06f
8 changed files with 262 additions and 151 deletions

View File

@ -1286,6 +1286,7 @@ LE64_BITMASK(BCH_SB_ERASURE_CODE, struct bch_sb, flags[3], 0, 16);
* reflink: gates KEY_TYPE_reflink
* inline_data: gates KEY_TYPE_inline_data
* new_siphash: gates BCH_STR_HASH_SIPHASH
* new_extent_overwrite: gates BTREE_NODE_NEW_EXTENT_OVERWRITE
*/
#define BCH_SB_FEATURES() \
x(lz4, 0) \
@ -1296,7 +1297,8 @@ LE64_BITMASK(BCH_SB_ERASURE_CODE, struct bch_sb, flags[3], 0, 16);
x(journal_seq_blacklist_v3, 5) \
x(reflink, 6) \
x(new_siphash, 7) \
x(inline_data, 8)
x(inline_data, 8) \
x(new_extent_overwrite, 9)
enum bch_sb_feature {
#define x(f, n) BCH_FEATURE_##f,
@ -1620,7 +1622,9 @@ struct btree_node {
LE64_BITMASK(BTREE_NODE_ID, struct btree_node, flags, 0, 4);
LE64_BITMASK(BTREE_NODE_LEVEL, struct btree_node, flags, 4, 8);
/* 8-32 unused */
LE64_BITMASK(BTREE_NODE_NEW_EXTENT_OVERWRITE,
struct btree_node, flags, 8, 9);
/* 9-32 unused */
LE64_BITMASK(BTREE_NODE_SEQ, struct btree_node, flags, 32, 64);
struct btree_node_entry {

View File

@ -130,24 +130,6 @@ bch2_key_sort_fix_overlapping(struct bch_fs *c, struct bset *dst,
return nr;
}
/*
* If keys compare equal, compare by pointer order:
*
* Necessary for sort_fix_overlapping() - if there are multiple keys that
* compare equal in different sets, we have to process them newest to oldest.
*/
static inline int extent_sort_fix_overlapping_cmp(struct btree *b,
struct bkey_packed *l,
struct bkey_packed *r)
{
struct bkey ul = bkey_unpack_key(b, l);
struct bkey ur = bkey_unpack_key(b, r);
return bkey_cmp(bkey_start_pos(&ul),
bkey_start_pos(&ur)) ?:
cmp_int((unsigned long) r, (unsigned long) l);
}
static void extent_sort_advance_prev(struct bkey_format *f,
struct btree_nr_keys *nr,
struct bkey_packed *start,
@ -188,6 +170,141 @@ static void extent_sort_append(struct bch_fs *c,
bkey_reassemble((void *) *prev, k.s_c);
}
/* Sort + repack in a new format: */
struct btree_nr_keys
bch2_sort_repack(struct bset *dst, struct btree *src,
struct btree_node_iter *src_iter,
struct bkey_format *out_f,
bool filter_whiteouts)
{
struct bkey_format *in_f = &src->format;
struct bkey_packed *in, *out = vstruct_last(dst);
struct btree_nr_keys nr;
memset(&nr, 0, sizeof(nr));
while ((in = bch2_btree_node_iter_next_all(src_iter, src))) {
if (filter_whiteouts && bkey_whiteout(in))
continue;
if (bch2_bkey_transform(out_f, out, bkey_packed(in)
? in_f : &bch2_bkey_format_current, in))
out->format = KEY_FORMAT_LOCAL_BTREE;
else
bch2_bkey_unpack(src, (void *) out, in);
btree_keys_account_key_add(&nr, 0, out);
out = bkey_next(out);
}
dst->u64s = cpu_to_le16((u64 *) out - dst->_data);
return nr;
}
/* Sort, repack, and merge: */
struct btree_nr_keys
bch2_sort_repack_merge(struct bch_fs *c,
struct bset *dst, struct btree *src,
struct btree_node_iter *iter,
struct bkey_format *out_f,
bool filter_whiteouts)
{
struct bkey_packed *prev = NULL, *k_packed;
struct bkey_s k;
struct btree_nr_keys nr;
struct bkey unpacked;
memset(&nr, 0, sizeof(nr));
while ((k_packed = bch2_btree_node_iter_next_all(iter, src))) {
if (filter_whiteouts && bkey_whiteout(k_packed))
continue;
k = __bkey_disassemble(src, k_packed, &unpacked);
if (filter_whiteouts &&
bch2_bkey_normalize(c, k))
continue;
extent_sort_append(c, out_f, &nr, vstruct_last(dst), &prev, k);
}
extent_sort_advance_prev(out_f, &nr, vstruct_last(dst), &prev);
dst->u64s = cpu_to_le16((u64 *) prev - dst->_data);
return nr;
}
static inline int sort_keys_cmp(struct btree *b,
struct bkey_packed *l,
struct bkey_packed *r)
{
return bkey_cmp_packed(b, l, r) ?:
(int) bkey_deleted(r) - (int) bkey_deleted(l) ?:
(int) l->needs_whiteout - (int) r->needs_whiteout;
}
unsigned bch2_sort_keys(struct bkey_packed *dst,
struct sort_iter *iter,
bool filter_whiteouts)
{
const struct bkey_format *f = &iter->b->format;
struct bkey_packed *in, *next, *out = dst;
sort_iter_sort(iter, sort_keys_cmp);
while ((in = sort_iter_next(iter, sort_keys_cmp))) {
if (bkey_whiteout(in) &&
(filter_whiteouts || !in->needs_whiteout))
continue;
if (bkey_whiteout(in) &&
(next = sort_iter_peek(iter)) &&
!bkey_cmp_packed(iter->b, in, next)) {
BUG_ON(in->needs_whiteout &&
next->needs_whiteout);
/*
* XXX racy, called with read lock from write path
*
* leads to spurious BUG_ON() in bkey_unpack_key() in
* debug mode
*/
next->needs_whiteout |= in->needs_whiteout;
continue;
}
if (bkey_whiteout(in)) {
memcpy_u64s(out, in, bkeyp_key_u64s(f, in));
set_bkeyp_val_u64s(f, out, 0);
} else {
bkey_copy(out, in);
}
out = bkey_next(out);
}
return (u64 *) out - (u64 *) dst;
}
/* Compat code for btree_node_old_extent_overwrite: */
/*
* If keys compare equal, compare by pointer order:
*
* Necessary for sort_fix_overlapping() - if there are multiple keys that
* compare equal in different sets, we have to process them newest to oldest.
*/
static inline int extent_sort_fix_overlapping_cmp(struct btree *b,
struct bkey_packed *l,
struct bkey_packed *r)
{
struct bkey ul = bkey_unpack_key(b, l);
struct bkey ur = bkey_unpack_key(b, r);
return bkey_cmp(bkey_start_pos(&ul),
bkey_start_pos(&ur)) ?:
cmp_int((unsigned long) r, (unsigned long) l);
}
struct btree_nr_keys
bch2_extent_sort_fix_overlapping(struct bch_fs *c, struct bset *dst,
struct sort_iter *iter)
@ -284,121 +401,6 @@ bch2_extent_sort_fix_overlapping(struct bch_fs *c, struct bset *dst,
return nr;
}
/* Sort + repack in a new format: */
struct btree_nr_keys
bch2_sort_repack(struct bset *dst, struct btree *src,
struct btree_node_iter *src_iter,
struct bkey_format *out_f,
bool filter_whiteouts)
{
struct bkey_format *in_f = &src->format;
struct bkey_packed *in, *out = vstruct_last(dst);
struct btree_nr_keys nr;
memset(&nr, 0, sizeof(nr));
while ((in = bch2_btree_node_iter_next_all(src_iter, src))) {
if (filter_whiteouts && bkey_whiteout(in))
continue;
if (bch2_bkey_transform(out_f, out, bkey_packed(in)
? in_f : &bch2_bkey_format_current, in))
out->format = KEY_FORMAT_LOCAL_BTREE;
else
bch2_bkey_unpack(src, (void *) out, in);
btree_keys_account_key_add(&nr, 0, out);
out = bkey_next(out);
}
dst->u64s = cpu_to_le16((u64 *) out - dst->_data);
return nr;
}
/* Sort, repack, and merge: */
struct btree_nr_keys
bch2_sort_repack_merge(struct bch_fs *c,
struct bset *dst, struct btree *src,
struct btree_node_iter *iter,
struct bkey_format *out_f,
bool filter_whiteouts)
{
struct bkey_packed *prev = NULL, *k_packed;
struct bkey_s k;
struct btree_nr_keys nr;
struct bkey unpacked;
memset(&nr, 0, sizeof(nr));
while ((k_packed = bch2_btree_node_iter_next_all(iter, src))) {
if (filter_whiteouts && bkey_whiteout(k_packed))
continue;
k = __bkey_disassemble(src, k_packed, &unpacked);
if (filter_whiteouts &&
bch2_bkey_normalize(c, k))
continue;
extent_sort_append(c, out_f, &nr, vstruct_last(dst), &prev, k);
}
extent_sort_advance_prev(out_f, &nr, vstruct_last(dst), &prev);
dst->u64s = cpu_to_le16((u64 *) prev - dst->_data);
return nr;
}
static inline int sort_keys_cmp(struct btree *b,
struct bkey_packed *l,
struct bkey_packed *r)
{
return bkey_cmp_packed(b, l, r) ?:
(int) bkey_whiteout(r) - (int) bkey_whiteout(l) ?:
(int) l->needs_whiteout - (int) r->needs_whiteout;
}
unsigned bch2_sort_keys(struct bkey_packed *dst,
struct sort_iter *iter,
bool filter_whiteouts)
{
const struct bkey_format *f = &iter->b->format;
struct bkey_packed *in, *next, *out = dst;
sort_iter_sort(iter, sort_keys_cmp);
while ((in = sort_iter_next(iter, sort_keys_cmp))) {
if (bkey_whiteout(in) &&
(filter_whiteouts || !in->needs_whiteout))
continue;
if (bkey_whiteout(in) &&
(next = sort_iter_peek(iter)) &&
!bkey_cmp_packed(iter->b, in, next)) {
BUG_ON(in->needs_whiteout &&
next->needs_whiteout);
/*
* XXX racy, called with read lock from write path
*
* leads to spurious BUG_ON() in bkey_unpack_key() in
* debug mode
*/
next->needs_whiteout |= in->needs_whiteout;
continue;
}
if (bkey_whiteout(in)) {
memcpy_u64s(out, in, bkeyp_key_u64s(f, in));
set_bkeyp_val_u64s(f, out, 0);
} else {
bkey_copy(out, in);
}
out = bkey_next(out);
}
return (u64 *) out - (u64 *) dst;
}
static inline int sort_extents_cmp(struct btree *b,
struct bkey_packed *l,
struct bkey_packed *r)

View File

@ -22,7 +22,8 @@
static void verify_no_dups(struct btree *b,
struct bkey_packed *start,
struct bkey_packed *end)
struct bkey_packed *end,
bool extents)
{
#ifdef CONFIG_BCACHEFS_DEBUG
struct bkey_packed *k, *p;
@ -36,7 +37,7 @@ static void verify_no_dups(struct btree *b,
struct bkey l = bkey_unpack_key(b, p);
struct bkey r = bkey_unpack_key(b, k);
BUG_ON(btree_node_is_extents(b)
BUG_ON(extents
? bkey_cmp(l.p, bkey_start_pos(&r)) > 0
: bkey_cmp(l.p, bkey_start_pos(&r)) >= 0);
//BUG_ON(bkey_cmp_packed(&b->format, p, k) >= 0);
@ -147,7 +148,8 @@ static void bch2_sort_whiteouts(struct bch_fs *c, struct btree *b)
}
verify_no_dups(b, new_whiteouts,
(void *) ((u64 *) new_whiteouts + b->whiteout_u64s));
(void *) ((u64 *) new_whiteouts + b->whiteout_u64s),
btree_node_old_extent_overwrite(b));
memcpy_u64s(unwritten_whiteouts_start(c, b),
new_whiteouts, b->whiteout_u64s);
@ -297,7 +299,8 @@ static bool bch2_compact_extent_whiteouts(struct bch_fs *c,
verify_no_dups(b,
unwritten_whiteouts_start(c, b),
unwritten_whiteouts_end(c, b));
unwritten_whiteouts_end(c, b),
true);
btree_bounce_free(c, order, used_mempool, whiteouts);
@ -377,7 +380,7 @@ static bool bch2_drop_whiteouts(struct btree *b, enum compact_mode mode)
bool bch2_compact_whiteouts(struct bch_fs *c, struct btree *b,
enum compact_mode mode)
{
return !btree_node_is_extents(b)
return !btree_node_old_extent_overwrite(b)
? bch2_drop_whiteouts(b, mode)
: bch2_compact_extent_whiteouts(c, b, mode);
}
@ -417,10 +420,10 @@ static void btree_node_sort(struct bch_fs *c, struct btree *b,
start_time = local_clock();
if (btree_node_is_extents(b))
if (btree_node_old_extent_overwrite(b))
filter_whiteouts = bset_written(b, start_bset);
u64s = (btree_node_is_extents(b)
u64s = (btree_node_old_extent_overwrite(b)
? bch2_sort_extents
: bch2_sort_keys)(out->keys.start,
&sort_iter,
@ -707,6 +710,7 @@ static int validate_bset(struct bch_fs *c, struct btree *b,
{
struct bkey_packed *k, *prev = NULL;
struct bpos prev_pos = POS_MIN;
struct bpos prev_data = POS_MIN;
bool seen_non_whiteout = false;
unsigned version;
const char *err;
@ -839,7 +843,8 @@ static int validate_bset(struct bch_fs *c, struct btree *b,
(bkey_cmp(prev_pos, bkey_start_pos(u.k)) > 0))) {
*whiteout_u64s = k->_data - i->_data;
seen_non_whiteout = true;
} else if (bkey_cmp(prev_pos, bkey_start_pos(u.k)) > 0) {
} else if (bkey_cmp(prev_data, bkey_start_pos(u.k)) > 0 ||
bkey_cmp(prev_pos, u.k->p) > 0) {
btree_err(BTREE_ERR_FATAL, c, b, i,
"keys out of order: %llu:%llu > %llu:%llu",
prev_pos.inode,
@ -849,7 +854,10 @@ static int validate_bset(struct bch_fs *c, struct btree *b,
/* XXX: repair this */
}
if (!bkey_deleted(u.k))
prev_data = u.k->p;
prev_pos = u.k->p;
prev = k;
k = bkey_next_skip_noops(k, vstruct_last(i));
}
@ -908,6 +916,10 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct btree *b, bool have_retry
bset_encrypt(c, i, b->written << 9);
if (btree_node_is_extents(b) &&
!BTREE_NODE_NEW_EXTENT_OVERWRITE(b->data))
set_btree_node_old_extent_overwrite(b);
sectors = vstruct_sectors(b->data, c->block_bits);
btree_node_set_format(b, b->data->format);
@ -971,7 +983,7 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct btree *b, bool have_retry
set_btree_bset(b, b->set, &b->data->keys);
b->nr = (btree_node_is_extents(b)
b->nr = (btree_node_old_extent_overwrite(b)
? bch2_extent_sort_fix_overlapping
: bch2_key_sort_fix_overlapping)(c, &sorted->keys, iter);
@ -1486,7 +1498,7 @@ void __bch2_btree_node_write(struct bch_fs *c, struct btree *b,
i->journal_seq = cpu_to_le64(seq);
i->u64s = 0;
if (!btree_node_is_extents(b)) {
if (!btree_node_old_extent_overwrite(b)) {
sort_iter_add(&sort_iter,
unwritten_whiteouts_start(c, b),
unwritten_whiteouts_end(c, b));
@ -1501,7 +1513,7 @@ void __bch2_btree_node_write(struct bch_fs *c, struct btree *b,
b->whiteout_u64s = 0;
u64s = btree_node_is_extents(b)
u64s = btree_node_old_extent_overwrite(b)
? bch2_sort_extents(vstruct_last(i), &sort_iter, false)
: bch2_sort_keys(i->start, &sort_iter, false);
le16_add_cpu(&i->u64s, u64s);

View File

@ -311,6 +311,7 @@ enum btree_flags {
BTREE_NODE_just_written,
BTREE_NODE_dying,
BTREE_NODE_fake,
BTREE_NODE_old_extent_overwrite,
};
BTREE_FLAG(read_in_flight);
@ -324,6 +325,7 @@ BTREE_FLAG(write_in_flight);
BTREE_FLAG(just_written);
BTREE_FLAG(dying);
BTREE_FLAG(fake);
BTREE_FLAG(old_extent_overwrite);
static inline struct btree_write *btree_current_write(struct btree *b)
{

View File

@ -374,6 +374,13 @@ static struct btree *bch2_btree_node_alloc(struct btree_update *as, unsigned lev
SET_BTREE_NODE_LEVEL(b->data, level);
b->data->ptr = bkey_i_to_btree_ptr(&b->key)->v.start[0];
if (c->sb.features & (1ULL << BCH_FEATURE_new_extent_overwrite))
SET_BTREE_NODE_NEW_EXTENT_OVERWRITE(b->data, true);
if (btree_node_is_extents(b) &&
!BTREE_NODE_NEW_EXTENT_OVERWRITE(b->data))
set_btree_node_old_extent_overwrite(b);
bch2_btree_build_aux_trees(b);
btree_node_will_make_reachable(as, b);

View File

@ -267,6 +267,8 @@ static void btree_insert_key_leaf(struct btree_trans *trans,
int old_live_u64s = b->nr.live_u64s;
int live_u64s_added, u64s_added;
insert->k->k.needs_whiteout = false;
if (!btree_node_is_extents(b))
bch2_insert_fixup_key(trans, insert);
else

View File

@ -186,11 +186,26 @@ bch2_extent_can_insert(struct btree_trans *trans,
overlap = bch2_extent_overlap(&insert->k->k, k.k);
/*
* If we're overwriting an existing extent, we may need to emit
* a whiteout - unless we're inserting a new extent at the same
* position:
*/
if (k.k->needs_whiteout &&
(!bkey_whiteout(&insert->k->k) ||
bkey_cmp(k.k->p, insert->k->k.p)))
*u64s += BKEY_U64s;
/*
* If we're partially overwriting an existing extent which has
* been written out to disk, we'll need to emit a new version of
* that extent:
*/
if (bkey_written(l->b, _k) &&
overlap != BCH_EXTENT_OVERLAP_ALL)
*u64s += _k->u64s;
/* account for having to split existing extent: */
/* And we may be splitting an existing extent: */
if (overlap == BCH_EXTENT_OVERLAP_MIDDLE)
*u64s += _k->u64s;
@ -286,6 +301,23 @@ static void extent_bset_insert(struct bch_fs *c, struct btree_iter *iter,
bch2_btree_node_iter_fix(iter, l->b, &l->iter, k, 0, k->u64s);
}
static void pack_push_whiteout(struct bch_fs *c, struct btree *b,
struct bpos pos)
{
struct bkey_packed k;
if (!bkey_pack_pos(&k, pos, b)) {
struct bkey_i tmp;
bkey_init(&tmp.k);
tmp.k.p = pos;
bkey_copy(&k, &tmp);
}
k.needs_whiteout = true;
push_whiteout(c, b, &k);
}
static void
extent_drop(struct bch_fs *c, struct btree_iter *iter,
struct bkey_packed *_k, struct bkey_s k)
@ -297,7 +329,12 @@ extent_drop(struct bch_fs *c, struct btree_iter *iter,
k.k->size = 0;
k.k->type = KEY_TYPE_deleted;
if (!btree_node_old_extent_overwrite(l->b) &&
k.k->needs_whiteout) {
pack_push_whiteout(c, l->b, k.k->p);
k.k->needs_whiteout = false;
}
if (_k >= btree_bset_last(l->b)->start) {
unsigned u64s = _k->u64s;
@ -322,12 +359,29 @@ extent_squash(struct bch_fs *c, struct btree_iter *iter,
bkey_on_stack_init(&tmp);
bkey_on_stack_init(&split);
if (!btree_node_old_extent_overwrite(l->b)) {
if (!bkey_whiteout(&insert->k) &&
!bkey_cmp(k.k->p, insert->k.p)) {
insert->k.needs_whiteout = k.k->needs_whiteout;
k.k->needs_whiteout = false;
}
} else {
insert->k.needs_whiteout |= k.k->needs_whiteout;
}
switch (overlap) {
case BCH_EXTENT_OVERLAP_FRONT:
if (bkey_written(l->b, _k)) {
bkey_on_stack_reassemble(&tmp, c, k.s_c);
bch2_cut_front(insert->k.p, tmp.k);
/*
* needs_whiteout was propagated to new version of @k,
* @tmp:
*/
if (!btree_node_old_extent_overwrite(l->b))
k.k->needs_whiteout = false;
extent_drop(c, iter, _k, k);
extent_bset_insert(c, iter, tmp.k);
} else {
@ -348,9 +402,26 @@ extent_squash(struct bch_fs *c, struct btree_iter *iter,
bkey_on_stack_reassemble(&tmp, c, k.s_c);
bch2_cut_back(bkey_start_pos(&insert->k), tmp.k);
/*
* @tmp has different position than @k, needs_whiteout
* should not be propagated:
*/
if (!btree_node_old_extent_overwrite(l->b))
tmp.k->k.needs_whiteout = false;
extent_drop(c, iter, _k, k);
extent_bset_insert(c, iter, tmp.k);
} else {
/*
* position of @k is changing, emit a whiteout if
* needs_whiteout is set:
*/
if (!btree_node_old_extent_overwrite(l->b) &&
k.k->needs_whiteout) {
pack_push_whiteout(c, l->b, k.k->p);
k.k->needs_whiteout = false;
}
btree_keys_account_val_delta(l->b, _k,
bch2_cut_back_s(bkey_start_pos(&insert->k), k));
extent_save(l->b, _k, k.k);
@ -367,10 +438,17 @@ extent_squash(struct bch_fs *c, struct btree_iter *iter,
bkey_on_stack_reassemble(&split, c, k.s_c);
bch2_cut_back(bkey_start_pos(&insert->k), split.k);
if (!btree_node_old_extent_overwrite(l->b))
split.k->k.needs_whiteout = false;
/* this is identical to BCH_EXTENT_OVERLAP_FRONT: */
if (bkey_written(l->b, _k)) {
bkey_on_stack_reassemble(&tmp, c, k.s_c);
bch2_cut_front(insert->k.p, tmp.k);
if (!btree_node_old_extent_overwrite(l->b))
k.k->needs_whiteout = false;
extent_drop(c, iter, _k, k);
extent_bset_insert(c, iter, tmp.k);
} else {
@ -462,7 +540,6 @@ void bch2_insert_fixup_extent(struct btree_trans *trans,
bch2_cut_front(cur_end, insert);
bch2_btree_iter_set_pos_same_leaf(iter, cur_end);
} else {
insert->k.needs_whiteout |= k.k->needs_whiteout;
extent_squash(c, iter, insert, _k, k, overlap);
}
@ -480,7 +557,10 @@ void bch2_insert_fixup_extent(struct btree_trans *trans,
if (insert->k.type == KEY_TYPE_deleted)
insert->k.type = KEY_TYPE_discard;
if (!bkey_whiteout(&insert->k) ||
btree_node_old_extent_overwrite(l->b))
extent_bset_insert(c, iter, insert);
bch2_btree_journal_key(trans, iter, insert);
}

View File

@ -908,6 +908,7 @@ int bch2_fs_recovery(struct bch_fs *c)
le16_to_cpu(bcachefs_metadata_version_min);
c->disk_sb.sb->version = le16_to_cpu(bcachefs_metadata_version_current);
c->disk_sb.sb->features[0] |= 1ULL << BCH_FEATURE_new_siphash;
c->disk_sb.sb->features[0] |= 1ULL << BCH_FEATURE_new_extent_overwrite;
write_sb = true;
}
@ -1027,6 +1028,7 @@ int bch2_fs_initialize(struct bch_fs *c)
le16_to_cpu(bcachefs_metadata_version_current);
c->disk_sb.sb->features[0] |= 1ULL << BCH_FEATURE_atomic_nlink;
c->disk_sb.sb->features[0] |= 1ULL << BCH_FEATURE_new_siphash;
c->disk_sb.sb->features[0] |= 1ULL << BCH_FEATURE_new_extent_overwrite;
SET_BCH_SB_INITIALIZED(c->disk_sb.sb, true);
SET_BCH_SB_CLEAN(c->disk_sb.sb, false);