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bcachefs: backpointers fsck no longer uses BTREE_ITER_ALL_LEVELS

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It appears that BTREE_ITER_ALL_LEVELS is racy with concurrent interior
node btree updates; unfortunate but not terribly surprising it's a
difficult problem - that was the original reason for gc_lock.

BTREE_ITER_ALL_LEVELS will probably be deleted in a subsequent patch,
this changes backpointers fsck to instead walk keys at one level of the
btree at a time.

This fixes the tiering_drop_alloc test, which stopped working with the
patch to not flush the journal after journal replay.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2023-11-12 20:20:35 -05:00
parent eb54e81f27
commit cd404e5b05
1 changed files with 63 additions and 64 deletions
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127
fs/bcachefs/backpointers.c
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@ -426,11 +426,13 @@ static int check_bp_exists(struct btree_trans *trans,
memcmp(bkey_s_c_to_backpointer(bp_k).v, &bp, sizeof(bp))) {
if (last_flushed->level != bp.level ||
!bpos_eq(last_flushed->pos, orig_k.k->p)) {
ret = bch2_btree_write_buffer_flush_sync(trans);
if (ret)
goto err;
last_flushed->level = bp.level;
last_flushed->pos = orig_k.k->p;
ret = bch2_btree_write_buffer_flush_sync(trans) ?:
-BCH_ERR_transaction_restart_write_buffer_flush;
ret = -BCH_ERR_transaction_restart_write_buffer_flush;
goto out;
}
goto missing;
@ -457,25 +459,18 @@ missing:
}
static int check_extent_to_backpointers(struct btree_trans *trans,
struct btree_iter *iter,
enum btree_id btree, unsigned level,
struct bpos bucket_start,
struct bpos bucket_end,
struct bpos_level *last_flushed)
struct bpos_level *last_flushed,
struct bkey_s_c k)
{
struct bch_fs *c = trans->c;
struct bkey_ptrs_c ptrs;
const union bch_extent_entry *entry;
struct extent_ptr_decoded p;
struct bkey_s_c k;
int ret;
k = bch2_btree_iter_peek_all_levels(iter);
ret = bkey_err(k);
if (ret)
return ret;
if (!k.k)
return 0;
ptrs = bch2_bkey_ptrs_c(k);
bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
struct bpos bucket_pos;
@ -484,7 +479,7 @@ static int check_extent_to_backpointers(struct btree_trans *trans,
if (p.ptr.cached)
continue;
bch2_extent_ptr_to_bp(c, iter->btree_id, iter->path->level,
bch2_extent_ptr_to_bp(c, btree, level,
k, p, &bucket_pos, &bp);
ret = check_bp_exists(trans, bucket_pos, bp, k,
@ -501,44 +496,33 @@ static int check_btree_root_to_backpointers(struct btree_trans *trans,
enum btree_id btree_id,
struct bpos bucket_start,
struct bpos bucket_end,
struct bpos_level *last_flushed)
struct bpos_level *last_flushed,
int *level)
{
struct bch_fs *c = trans->c;
struct btree_root *r = bch2_btree_id_root(c, btree_id);
struct btree_iter iter;
struct btree *b;
struct bkey_s_c k;
struct bkey_ptrs_c ptrs;
struct extent_ptr_decoded p;
const union bch_extent_entry *entry;
int ret;
bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN, 0, r->level, 0);
retry:
bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN,
0, bch2_btree_id_root(c, btree_id)->b->c.level, 0);
b = bch2_btree_iter_peek_node(&iter);
ret = PTR_ERR_OR_ZERO(b);
if (ret)
goto err;
BUG_ON(b != btree_node_root(c, b));
if (b != btree_node_root(c, b)) {
bch2_trans_iter_exit(trans, &iter);
goto retry;
}
*level = b->c.level;
k = bkey_i_to_s_c(&b->key);
ptrs = bch2_bkey_ptrs_c(k);
bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
struct bpos bucket_pos;
struct bch_backpointer bp;
if (p.ptr.cached)
continue;
bch2_extent_ptr_to_bp(c, iter.btree_id, b->c.level + 1,
k, p, &bucket_pos, &bp);
ret = check_bp_exists(trans, bucket_pos, bp, k,
ret = check_extent_to_backpointers(trans, btree_id, b->c.level + 1,
bucket_start, bucket_end,
last_flushed);
if (ret)
goto err;
}
last_flushed, k);
err:
bch2_trans_iter_exit(trans, &iter);
return ret;
@ -616,43 +600,58 @@ static int bch2_check_extents_to_backpointers_pass(struct btree_trans *trans,
struct bch_fs *c = trans->c;
struct btree_iter iter;
enum btree_id btree_id;
struct bpos_level last_flushed = { UINT_MAX, POS_MIN };
struct bkey_s_c k;
int ret = 0;
for (btree_id = 0; btree_id < btree_id_nr_alive(c); btree_id++) {
unsigned depth = btree_type_has_ptrs(btree_id) ? 0 : 1;
bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN, 0,
depth,
BTREE_ITER_ALL_LEVELS|
BTREE_ITER_PREFETCH);
do {
ret = commit_do(trans, NULL, NULL,
BCH_TRANS_COMMIT_lazy_rw|
BCH_TRANS_COMMIT_no_enospc,
check_extent_to_backpointers(trans, &iter,
bucket_start, bucket_end,
&last_flushed));
if (ret)
break;
} while (!bch2_btree_iter_advance(&iter));
bch2_trans_iter_exit(trans, &iter);
if (ret)
break;
struct bpos_level last_flushed = { UINT_MAX, POS_MIN };
int level, depth = btree_type_has_ptrs(btree_id) ? 0 : 1;
ret = commit_do(trans, NULL, NULL,
BCH_TRANS_COMMIT_lazy_rw|
BCH_TRANS_COMMIT_no_enospc,
check_btree_root_to_backpointers(trans, btree_id,
bucket_start, bucket_end,
&last_flushed));
&last_flushed, &level));
if (ret)
break;
return ret;
while (level >= depth) {
bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN, 0,
level,
BTREE_ITER_PREFETCH);
while (1) {
bch2_trans_begin(trans);
k = bch2_btree_iter_peek(&iter);
if (!k.k)
break;
ret = bkey_err(k) ?:
check_extent_to_backpointers(trans, btree_id, level,
bucket_start, bucket_end,
&last_flushed, k) ?:
bch2_trans_commit(trans, NULL, NULL,
BCH_TRANS_COMMIT_lazy_rw|
BCH_TRANS_COMMIT_no_enospc);
if (bch2_err_matches(ret, BCH_ERR_transaction_restart)) {
ret = 0;
continue;
}
if (ret)
break;
if (bpos_eq(iter.pos, SPOS_MAX))
break;
bch2_btree_iter_advance(&iter);
}
bch2_trans_iter_exit(trans, &iter);
if (ret)
return ret;
--level;
}
}
return ret;
return 0;
}
static struct bpos bucket_pos_to_bp_safe(const struct bch_fs *c,