kevin/linux
1
Fork 0
Code

bcachefs: Self healing on read IO error

Browse Source 
This repurposes the promote path, which already knows how to call
data_update() after a read: we now automatically rewrite bad data when
we get a read error and then successfully retry from a different
replica.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2024-06-28 13:28:30 -04:00
parent b1d63b06e8
commit a2cb8a6236
3 changed files with 53 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
fs/bcachefs/extents.c
View File

@ -37,8 +37,8 @@ static void bch2_extent_crc_pack(union bch_extent_crc *,
struct bch_extent_crc_unpacked,
enum bch_extent_entry_type);
static struct bch_dev_io_failures *dev_io_failures(struct bch_io_failures *f,
unsigned dev)
struct bch_dev_io_failures *bch2_dev_io_failures(struct bch_io_failures *f,
unsigned dev)
{
struct bch_dev_io_failures *i;
@ -52,7 +52,7 @@ static struct bch_dev_io_failures *dev_io_failures(struct bch_io_failures *f,
void bch2_mark_io_failure(struct bch_io_failures *failed,
struct extent_ptr_decoded *p)
{
struct bch_dev_io_failures *f = dev_io_failures(failed, p->ptr.dev);
struct bch_dev_io_failures *f = bch2_dev_io_failures(failed, p->ptr.dev);
if (!f) {
BUG_ON(failed->nr >= ARRAY_SIZE(failed->devs));
@ -140,7 +140,7 @@ int bch2_bkey_pick_read_device(struct bch_fs *c, struct bkey_s_c k,
if (p.ptr.cached && (!ca || dev_ptr_stale_rcu(ca, &p.ptr)))
continue;
f = failed ? dev_io_failures(failed, p.ptr.dev) : NULL;
f = failed ? bch2_dev_io_failures(failed, p.ptr.dev) : NULL;
if (f)
p.idx = f->nr_failed < f->nr_retries
? f->idx

2
fs/bcachefs/extents.h
View File

@ -399,6 +399,8 @@ out: \
/* utility code common to all keys with pointers: */
struct bch_dev_io_failures *bch2_dev_io_failures(struct bch_io_failures *,
unsigned);
void bch2_mark_io_failure(struct bch_io_failures *,
struct extent_ptr_decoded *);
int bch2_bkey_pick_read_device(struct bch_fs *, struct bkey_s_c,

69
fs/bcachefs/io_read.c
View File

@ -93,21 +93,24 @@ static const struct rhashtable_params bch_promote_params = {
static inline int should_promote(struct bch_fs *c, struct bkey_s_c k,
struct bpos pos,
struct bch_io_opts opts,
unsigned flags)
unsigned flags,
struct bch_io_failures *failed)
{
BUG_ON(!opts.promote_target);
if (!failed) {
BUG_ON(!opts.promote_target);
if (!(flags & BCH_READ_MAY_PROMOTE))
return -BCH_ERR_nopromote_may_not;
if (!(flags & BCH_READ_MAY_PROMOTE))
return -BCH_ERR_nopromote_may_not;
if (bch2_bkey_has_target(c, k, opts.promote_target))
return -BCH_ERR_nopromote_already_promoted;
if (bch2_bkey_has_target(c, k, opts.promote_target))
return -BCH_ERR_nopromote_already_promoted;
if (bkey_extent_is_unwritten(k))
return -BCH_ERR_nopromote_unwritten;
if (bkey_extent_is_unwritten(k))
return -BCH_ERR_nopromote_unwritten;
if (bch2_target_congested(c, opts.promote_target))
return -BCH_ERR_nopromote_congested;
if (bch2_target_congested(c, opts.promote_target))
return -BCH_ERR_nopromote_congested;
}
if (rhashtable_lookup_fast(&c->promote_table, &pos,
bch_promote_params))
@ -164,7 +167,8 @@ static struct promote_op *__promote_alloc(struct btree_trans *trans,
struct extent_ptr_decoded *pick,
struct bch_io_opts opts,
unsigned sectors,
struct bch_read_bio **rbio)
struct bch_read_bio **rbio,
struct bch_io_failures *failed)
{
struct bch_fs *c = trans->c;
struct promote_op *op = NULL;
@ -217,14 +221,28 @@ static struct promote_op *__promote_alloc(struct btree_trans *trans,
bio = &op->write.op.wbio.bio;
bio_init(bio, NULL, bio->bi_inline_vecs, pages, 0);
struct data_update_opts update_opts = {};
if (!failed) {
update_opts.target = opts.promote_target;
update_opts.extra_replicas = 1;
update_opts.write_flags = BCH_WRITE_ALLOC_NOWAIT|BCH_WRITE_CACHED;
} else {
update_opts.target = opts.foreground_target;
struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
unsigned i = 0;
bkey_for_each_ptr(ptrs, ptr) {
if (bch2_dev_io_failures(failed, ptr->dev))
update_opts.rewrite_ptrs |= BIT(i);
i++;
}
}
ret = bch2_data_update_init(trans, NULL, NULL, &op->write,
writepoint_hashed((unsigned long) current),
opts,
(struct data_update_opts) {
.target = opts.promote_target,
.extra_replicas = 1,
.write_flags = BCH_WRITE_ALLOC_NOWAIT|BCH_WRITE_CACHED,
},
update_opts,
btree_id, k);
/*
* possible errors: -BCH_ERR_nocow_lock_blocked,
@ -258,10 +276,17 @@ static struct promote_op *promote_alloc(struct btree_trans *trans,
unsigned flags,
struct bch_read_bio **rbio,
bool *bounce,
bool *read_full)
bool *read_full,
struct bch_io_failures *failed)
{
struct bch_fs *c = trans->c;
bool promote_full = *read_full || READ_ONCE(c->promote_whole_extents);
/*
* if failed != NULL we're not actually doing a promote, we're
* recovering from an io/checksum error
*/
bool promote_full = (failed ||
*read_full ||
READ_ONCE(c->promote_whole_extents));
/* data might have to be decompressed in the write path: */
unsigned sectors = promote_full
? max(pick->crc.compressed_size, pick->crc.live_size)
@ -272,7 +297,7 @@ static struct promote_op *promote_alloc(struct btree_trans *trans,
struct promote_op *promote;
int ret;
ret = should_promote(c, k, pos, opts, flags);
ret = should_promote(c, k, pos, opts, flags, failed);
if (ret)
goto nopromote;
@ -280,7 +305,7 @@ static struct promote_op *promote_alloc(struct btree_trans *trans,
k.k->type == KEY_TYPE_reflink_v
? BTREE_ID_reflink
: BTREE_ID_extents,
k, pos, pick, opts, sectors, rbio);
k, pos, pick, opts, sectors, rbio, failed);
ret = PTR_ERR_OR_ZERO(promote);
if (ret)
goto nopromote;
@ -910,9 +935,9 @@ retry_pick:
bounce = true;
}
if (orig->opts.promote_target)
if (orig->opts.promote_target)// || failed)
promote = promote_alloc(trans, iter, k, &pick, orig->opts, flags,
&rbio, &bounce, &read_full);
&rbio, &bounce, &read_full, failed);
if (!read_full) {
EBUG_ON(crc_is_compressed(pick.crc));