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bcachefs: bch2_btree_write_buffer_flush_going_ro()

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The write buffer needs to be specifically flushed when going RO: keys in
the journal that haven't yet been moved to the write buffer don't have a
journal pin yet.

This fixes numerous syzbot bugs, all with symptoms of still doing writes
after we've got RO.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2024-11-07 21:48:33 -05:00
parent 8440da9331
commit ca43f73cd1
3 changed files with 29 additions and 3 deletions
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30
fs/bcachefs/btree_write_buffer.c
View File

@ -277,6 +277,10 @@ static int bch2_btree_write_buffer_flush_locked(struct btree_trans *trans)
bool accounting_replay_done = test_bit(BCH_FS_accounting_replay_done, &c->flags);
int ret = 0;
ret = bch2_journal_error(&c->journal);
if (ret)
return ret;
bch2_trans_unlock(trans);
bch2_trans_begin(trans);
@ -491,7 +495,8 @@ static int fetch_wb_keys_from_journal(struct bch_fs *c, u64 seq)
return ret;
}
static int btree_write_buffer_flush_seq(struct btree_trans *trans, u64 seq)
static int btree_write_buffer_flush_seq(struct btree_trans *trans, u64 seq,
bool *did_work)
{
struct bch_fs *c = trans->c;
struct btree_write_buffer *wb = &c->btree_write_buffer;
@ -502,6 +507,8 @@ static int btree_write_buffer_flush_seq(struct btree_trans *trans, u64 seq)
fetch_from_journal_err = fetch_wb_keys_from_journal(c, seq);
*did_work |= wb->inc.keys.nr || wb->flushing.keys.nr;
/*
* On memory allocation failure, bch2_btree_write_buffer_flush_locked()
* is not guaranteed to empty wb->inc:
@ -521,17 +528,34 @@ static int bch2_btree_write_buffer_journal_flush(struct journal *j,
struct journal_entry_pin *_pin, u64 seq)
{
struct bch_fs *c = container_of(j, struct bch_fs, journal);
bool did_work = false;
return bch2_trans_run(c, btree_write_buffer_flush_seq(trans, seq));
return bch2_trans_run(c, btree_write_buffer_flush_seq(trans, seq, &did_work));
}
int bch2_btree_write_buffer_flush_sync(struct btree_trans *trans)
{
struct bch_fs *c = trans->c;
bool did_work = false;
trace_and_count(c, write_buffer_flush_sync, trans, _RET_IP_);
return btree_write_buffer_flush_seq(trans, journal_cur_seq(&c->journal));
return btree_write_buffer_flush_seq(trans, journal_cur_seq(&c->journal), &did_work);
}
/*
* The write buffer requires flushing when going RO: keys in the journal for the
* write buffer don't have a journal pin yet
*/
bool bch2_btree_write_buffer_flush_going_ro(struct bch_fs *c)
{
if (bch2_journal_error(&c->journal))
return false;
bool did_work = false;
bch2_trans_run(c, btree_write_buffer_flush_seq(trans,
journal_cur_seq(&c->journal), &did_work));
return did_work;
}
int bch2_btree_write_buffer_flush_nocheck_rw(struct btree_trans *trans)

1
fs/bcachefs/btree_write_buffer.h
View File

@ -21,6 +21,7 @@ static inline bool bch2_btree_write_buffer_must_wait(struct bch_fs *c)
struct btree_trans;
int bch2_btree_write_buffer_flush_sync(struct btree_trans *);
bool bch2_btree_write_buffer_flush_going_ro(struct bch_fs *);
int bch2_btree_write_buffer_flush_nocheck_rw(struct btree_trans *);
int bch2_btree_write_buffer_tryflush(struct btree_trans *);

1
fs/bcachefs/super.c
View File

@ -272,6 +272,7 @@ static void __bch2_fs_read_only(struct bch_fs *c)
clean_passes++;
if (bch2_btree_interior_updates_flush(c) ||
bch2_btree_write_buffer_flush_going_ro(c) ||
bch2_journal_flush_all_pins(&c->journal) ||
bch2_btree_flush_all_writes(c) ||
seq != atomic64_read(&c->journal.seq)) {