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bcachefs: Be precise about bch_io_failures

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If the extent we're reading from changes, due to be being overwritten or
moved (possibly partially) - we need to reset bch_io_failures so that we
don't accidentally mark a new extent as poisoned prematurely.

This means we have to separately track (in the retry path) the extent we
previously read from.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet
2025-03-10 13:33:41 -04:00
parent 0e5f1f3f8f
commit 6659ba3b18
3 changed files with 52 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
fs/bcachefs/bkey.h
View File

@@ -191,6 +191,7 @@ static inline struct bpos bkey_max(struct bpos l, struct bpos r)
static inline bool bkey_and_val_eq(struct bkey_s_c l, struct bkey_s_c r)
{
return bpos_eq(l.k->p, r.k->p) &&
l.k->size == r.k->size &&
bkey_bytes(l.k) == bkey_bytes(r.k) &&
!memcmp(l.v, r.v, bkey_val_bytes(l.k));
}

51
fs/bcachefs/io_read.c
View File

@@ -296,6 +296,13 @@ static struct bch_read_bio *promote_alloc(struct btree_trans *trans,
bool *read_full,
struct bch_io_failures *failed)
{
/*
* We're in the retry path, but we don't know what to repair yet, and we
* don't want to do a promote here:
*/
if (failed && !failed->nr)
return NULL;
struct bch_fs *c = trans->c;
/*
* if failed != NULL we're not actually doing a promote, we're
@@ -430,6 +437,28 @@ static void bch2_rbio_done(struct bch_read_bio *rbio)
bio_endio(&rbio->bio);
}
static void get_rbio_extent(struct btree_trans *trans,
struct bch_read_bio *rbio,
struct bkey_buf *sk)
{
struct btree_iter iter;
struct bkey_s_c k;
int ret = lockrestart_do(trans,
bkey_err(k = bch2_bkey_get_iter(trans, &iter,
rbio->data_btree, rbio->data_pos, 0)));
if (ret)
return;
struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
bkey_for_each_ptr(ptrs, ptr)
if (bch2_extent_ptr_eq(*ptr, rbio->pick.ptr)) {
bch2_bkey_buf_reassemble(sk, trans->c, k);
break;
}
bch2_trans_iter_exit(trans, &iter);
}
static noinline int bch2_read_retry_nodecode(struct btree_trans *trans,
struct bch_read_bio *rbio,
struct bvec_iter bvec_iter,
@@ -491,11 +520,18 @@ static void bch2_rbio_retry(struct work_struct *work)
struct btree_trans *trans = bch2_trans_get(c);
struct bkey_buf sk;
bch2_bkey_buf_init(&sk);
bkey_init(&sk.k->k);
trace_io_read_retry(&rbio->bio);
this_cpu_add(c->counters[BCH_COUNTER_io_read_retry],
bvec_iter_sectors(rbio->bvec_iter));
if (bch2_err_matches(rbio->ret, BCH_ERR_data_read_retry_avoid))
get_rbio_extent(trans, rbio, &sk);
if (!bkey_deleted(&sk.k->k) &&
bch2_err_matches(rbio->ret, BCH_ERR_data_read_retry_avoid))
bch2_mark_io_failure(&failed, &rbio->pick,
rbio->ret == -BCH_ERR_data_read_retry_csum_err);
@@ -516,7 +552,7 @@ static void bch2_rbio_retry(struct work_struct *work)
int ret = rbio->data_update
? bch2_read_retry_nodecode(trans, rbio, iter, &failed, flags)
: __bch2_read(trans, rbio, iter, inum, &failed, flags);
: __bch2_read(trans, rbio, iter, inum, &failed, &sk, flags);
if (ret) {
rbio->ret = ret;
@@ -539,6 +575,7 @@ static void bch2_rbio_retry(struct work_struct *work)
}
bch2_rbio_done(rbio);
bch2_bkey_buf_exit(&sk, c);
bch2_trans_put(trans);
}
@@ -1265,7 +1302,9 @@ int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig,
int __bch2_read(struct btree_trans *trans, struct bch_read_bio *rbio,
struct bvec_iter bvec_iter, subvol_inum inum,
struct bch_io_failures *failed, unsigned flags)
struct bch_io_failures *failed,
struct bkey_buf *prev_read,
unsigned flags)
{
struct bch_fs *c = trans->c;
struct btree_iter iter;
@@ -1313,6 +1352,12 @@ int __bch2_read(struct btree_trans *trans, struct bch_read_bio *rbio,
k = bkey_i_to_s_c(sk.k);
if (unlikely(flags & BCH_READ_in_retry)) {
if (!bkey_and_val_eq(k, bkey_i_to_s_c(prev_read->k)))
failed->nr = 0;
bch2_bkey_buf_copy(prev_read, c, sk.k);
}
/*
* With indirect extents, the amount of data to read is the min
* of the original extent and the indirect extent:

5
fs/bcachefs/io_read.h
View File

@@ -144,7 +144,8 @@ static inline void bch2_read_extent(struct btree_trans *trans,
}
int __bch2_read(struct btree_trans *, struct bch_read_bio *, struct bvec_iter,
subvol_inum, struct bch_io_failures *, unsigned flags);
subvol_inum,
struct bch_io_failures *, struct bkey_buf *, unsigned flags);
static inline void bch2_read(struct bch_fs *c, struct bch_read_bio *rbio,
subvol_inum inum)
@@ -154,7 +155,7 @@ static inline void bch2_read(struct bch_fs *c, struct bch_read_bio *rbio,
rbio->subvol = inum.subvol;
bch2_trans_run(c,
__bch2_read(trans, rbio, rbio->bio.bi_iter, inum, NULL,
__bch2_read(trans, rbio, rbio->bio.bi_iter, inum, NULL, NULL,
BCH_READ_retry_if_stale|
BCH_READ_may_promote|
BCH_READ_user_mapped));