diff options
| author | Kent Overstreet <kent.overstreet@gmail.com> | 2020-05-13 00:15:28 -0400 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@gmail.com> | 2020-06-09 21:32:45 -0400 |
| commit | a1a0adbdb30ca795e2abdef579b79a4140711095 (patch) | |
| tree | 8844dfec167f893c6d9861beca8325c37fd2e9d9 | |
| parent | 1d7068cc09af84af4826b97a9647b8b89f9a99e1 (diff) | |
bcachefs: Fix a workqueue deadlock
writes running out of a workqueue (via dio path) could block and prevent
other writes from calling bch2_write_index() and completing.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
| -rw-r--r-- | fs/bcachefs/io.c | 29 | ||||
| -rw-r--r-- | fs/bcachefs/io.h | 1 |
2 files changed, 28 insertions, 2 deletions
diff --git a/fs/bcachefs/io.c b/fs/bcachefs/io.c index 19059702428a..5801a036391e 100644 --- a/fs/bcachefs/io.c +++ b/fs/bcachefs/io.c @@ -588,7 +588,9 @@ static void bch2_write_index(struct closure *cl) __bch2_write_index(op); - if (!op->error && (op->flags & BCH_WRITE_FLUSH)) { + if (!(op->flags & BCH_WRITE_DONE)) { + continue_at(cl, __bch2_write, index_update_wq(op)); + } else if (!op->error && (op->flags & BCH_WRITE_FLUSH)) { bch2_journal_flush_seq_async(&c->journal, *op_journal_seq(op), cl); @@ -1103,8 +1105,15 @@ again: if (ret < 0) goto err; - if (ret) + if (ret) { skip_put = false; + } else { + /* + * for the skip_put optimization this has to be set + * before we submit the bio: + */ + op->flags |= BCH_WRITE_DONE; + } bio->bi_end_io = bch2_write_endio; bio->bi_private = &op->cl; @@ -1127,16 +1136,30 @@ again: return; err: op->error = ret; + op->flags |= BCH_WRITE_DONE; continue_at(cl, bch2_write_index, index_update_wq(op)); return; flush_io: + /* + * If the write can't all be submitted at once, we generally want to + * block synchronously as that signals backpressure to the caller. + * + * However, if we're running out of a workqueue, we can't block here + * because we'll be blocking other work items from completing: + */ + if (current->flags & PF_WQ_WORKER) { + continue_at(cl, bch2_write_index, index_update_wq(op)); + return; + } + closure_sync(cl); if (!bch2_keylist_empty(&op->insert_keys)) { __bch2_write_index(op); if (op->error) { + op->flags |= BCH_WRITE_DONE; continue_at_nobarrier(cl, bch2_write_done, NULL); return; } @@ -1182,6 +1205,8 @@ static void bch2_write_data_inline(struct bch_write_op *op, unsigned data_len) bch2_keylist_push(&op->insert_keys); op->flags |= BCH_WRITE_WROTE_DATA_INLINE; + op->flags |= BCH_WRITE_DONE; + continue_at_nobarrier(cl, bch2_write_index, NULL); return; err: diff --git a/fs/bcachefs/io.h b/fs/bcachefs/io.h index e45dcf9635ae..c4c847306345 100644 --- a/fs/bcachefs/io.h +++ b/fs/bcachefs/io.h @@ -36,6 +36,7 @@ enum bch_write_flags { /* Internal: */ BCH_WRITE_JOURNAL_SEQ_PTR = (1 << 10), BCH_WRITE_SKIP_CLOSURE_PUT = (1 << 11), + BCH_WRITE_DONE = (1 << 12), }; static inline u64 *op_journal_seq(struct bch_write_op *op) |