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bcachefs: Rework __bch2_data_update_index_update()

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This makes some improvements to the logic for adding/removing replicas,
as part of the larger erasure coding improvements. We now directly
consider number of replicas desired for the given inode, and
extent/pointer durability: this ensures that the extent ends up with the
desired number of replicas when we're replacing multiple pointers with
one that has higher durability (e.g. erasure coded).

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2023-03-04 03:21:34 -05:00
parent 702ffea204
commit 57c723de7d
1 changed files with 52 additions and 52 deletions
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104
fs/bcachefs/data_update.c
View file

@ -91,18 +91,6 @@ static int insert_snapshot_whiteouts(struct btree_trans *trans,
return ret;
}
static void bch2_bkey_mark_dev_cached(struct bkey_s k, unsigned dev)
{
struct bkey_ptrs ptrs = bch2_bkey_ptrs(k);
struct bch_extent_ptr *ptr;
bkey_for_each_ptr(ptrs, ptr)
if (ptr->dev == dev) {
bch2_extent_ptr_set_cached(k, ptr);
return;
}
}
static int __bch2_data_update_index_update(struct btree_trans *trans,
struct bch_write_op *op)
{
@ -125,15 +113,17 @@ static int __bch2_data_update_index_update(struct btree_trans *trans,
while (1) {
struct bkey_s_c k;
struct bkey_s_c old = bkey_i_to_s_c(m->k.k);
struct bkey_i *insert;
struct bkey_i *insert = NULL;
struct bkey_i_extent *new;
const union bch_extent_entry *entry;
const union bch_extent_entry *entry_c;
union bch_extent_entry *entry;
struct extent_ptr_decoded p;
struct bch_extent_ptr *ptr;
const struct bch_extent_ptr *ptr_c;
struct bpos next_pos;
bool did_work = false;
bool should_check_enospc;
s64 i_sectors_delta = 0, disk_sectors_delta = 0;
unsigned i;
unsigned rewrites_found = 0, durability, i;
bch2_trans_begin(trans);
@ -145,7 +135,7 @@ static int __bch2_data_update_index_update(struct btree_trans *trans,
new = bkey_i_to_extent(bch2_keylist_front(keys));
if (!bch2_extents_match(k, old))
goto nomatch;
goto nowork;
bkey_reassemble(_insert.k, k);
insert = _insert.k;
@ -168,50 +158,60 @@ static int __bch2_data_update_index_update(struct btree_trans *trans,
* Fist, drop rewrite_ptrs from @new:
*/
i = 0;
bkey_for_each_ptr_decode(old.k, bch2_bkey_ptrs_c(old), p, entry) {
bkey_for_each_ptr_decode(old.k, bch2_bkey_ptrs_c(old), p, entry_c) {
if (((1U << i) & m->data_opts.rewrite_ptrs) &&
bch2_extent_has_ptr(old, p, bkey_i_to_s(insert))) {
/*
* If we're going to be adding a pointer to the
* same device, we have to drop the old one -
* otherwise, we can just mark it cached:
*/
if (bch2_bkey_has_device_c(bkey_i_to_s_c(&new->k_i), p.ptr.dev))
bch2_bkey_drop_device_noerror(bkey_i_to_s(insert), p.ptr.dev);
else
bch2_bkey_mark_dev_cached(bkey_i_to_s(insert), p.ptr.dev);
(ptr = bch2_extent_has_ptr(old, p, bkey_i_to_s(insert))) &&
!ptr->cached) {
bch2_extent_ptr_set_cached(bkey_i_to_s(insert), ptr);
rewrites_found |= 1U << i;
}
i++;
}
if (m->data_opts.rewrite_ptrs &&
!rewrites_found &&
bch2_bkey_durability(c, k) >= m->op.opts.data_replicas)
goto nowork;
/* Add new ptrs: */
extent_for_each_ptr_decode(extent_i_to_s(new), p, entry) {
const struct bch_extent_ptr *existing_ptr =
bch2_bkey_has_device_c(bkey_i_to_s_c(insert), p.ptr.dev);
if (existing_ptr && existing_ptr->cached) {
/*
* We're replacing a cached pointer with a non
* cached pointer:
*/
bch2_bkey_drop_device_noerror(bkey_i_to_s(insert),
existing_ptr->dev);
} else if (existing_ptr) {
/*
* raced with another move op? extent already
* has a pointer to the device we just wrote
* data to
*/
continue;
/*
* A replica that we just wrote might conflict with a replica
* that we want to keep, due to racing with another move:
*/
restart_drop_conflicting_replicas:
extent_for_each_ptr(extent_i_to_s(new), ptr)
if ((ptr_c = bch2_bkey_has_device_c(bkey_i_to_s_c(insert), ptr->dev)) &&
!ptr_c->cached) {
bch2_bkey_drop_ptr_noerror(bkey_i_to_s(&new->k_i), ptr);
goto restart_drop_conflicting_replicas;
}
bch2_extent_ptr_decoded_append(insert, &p);
did_work = true;
if (!bkey_val_u64s(&new->k))
goto nowork;
/* Now, drop pointers that conflict with what we just wrote: */
extent_for_each_ptr_decode(extent_i_to_s(new), p, entry)
if ((ptr = bch2_bkey_has_device(bkey_i_to_s(insert), p.ptr.dev)))
bch2_bkey_drop_ptr_noerror(bkey_i_to_s(insert), ptr);
durability = bch2_bkey_durability(c, bkey_i_to_s_c(insert)) +
bch2_bkey_durability(c, bkey_i_to_s_c(&new->k_i));
/* Now, drop excess replicas: */
restart_drop_extra_replicas:
bkey_for_each_ptr_decode(old.k, bch2_bkey_ptrs(bkey_i_to_s(insert)), p, entry) {
unsigned ptr_durability = bch2_extent_ptr_durability(c, &p);
if (!p.ptr.cached &&
durability - ptr_durability >= m->op.opts.data_replicas) {
durability -= ptr_durability;
bch2_extent_ptr_set_cached(bkey_i_to_s(insert), &entry->ptr);
goto restart_drop_extra_replicas;
}
}
if (!did_work)
goto nomatch;
/* Finally, add the pointers we just wrote: */
extent_for_each_ptr_decode(extent_i_to_s(new), p, entry)
bch2_extent_ptr_decoded_append(insert, &p);
bch2_bkey_narrow_crcs(insert, (struct bch_extent_crc_unpacked) { 0 });
bch2_extent_normalize(c, bkey_i_to_s(insert));
@ -272,7 +272,7 @@ static int __bch2_data_update_index_update(struct btree_trans *trans,
goto out;
}
continue;
nomatch:
nowork:
if (m->ctxt && m->ctxt->stats) {
BUG_ON(k.k->p.offset <= iter.pos.offset);
atomic64_inc(&m->ctxt->stats->keys_raced);