bcachefs: Journal resize fixes

 - Fix a sleeping-in-atomic bug due to calling
   bch2_journal_buckets_to_sb() under the journal lock.
 - Additionally, now we mark buckets as journal buckets before adding
   them to the journal in memory and the superblock. This ensures that
   if we crash part way through we'll never be writing to journal
   buckets that aren't marked correctly.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/buckets.c

@@ -1855,7 +1855,7 @@ static int __bch2_trans_mark_metadata_bucket(struct btree_trans *trans,
 	if (IS_ERR(a))
 		return PTR_ERR(a);
 
-	if (a->v.data_type && a->v.data_type != type) {
+	if (a->v.data_type && type && a->v.data_type != type) {
 		bch2_fsck_err(c, FSCK_CAN_IGNORE|FSCK_NEED_FSCK,
 			"bucket %llu:%llu gen %u different types of data in same bucket: %s, %s\n"
 			"while marking %s",

fs/bcachefs/journal.c

@@ -757,19 +757,10 @@ static int __bch2_set_nr_journal_buckets(struct bch_dev *ca, unsigned nr,
 	u64 *new_bucket_seq = NULL, *new_buckets = NULL;
 	struct open_bucket **ob = NULL;
 	long *bu = NULL;
-	unsigned i, nr_got = 0, nr_want = nr - ja->nr;
-	unsigned old_nr			= ja->nr;
-	unsigned old_discard_idx	= ja->discard_idx;
-	unsigned old_dirty_idx_ondisk	= ja->dirty_idx_ondisk;
-	unsigned old_dirty_idx		= ja->dirty_idx;
-	unsigned old_cur_idx		= ja->cur_idx;
+	unsigned i, pos, nr_got = 0, nr_want = nr - ja->nr;
 	int ret = 0;
 
-	if (c) {
-		bch2_journal_flush_all_pins(&c->journal);
-		bch2_journal_block(&c->journal);
-		mutex_lock(&c->sb_lock);
-	}
+	BUG_ON(nr <= ja->nr);
 
 	bu		= kcalloc(nr_want, sizeof(*bu), GFP_KERNEL);
 	ob		= kcalloc(nr_want, sizeof(*ob), GFP_KERNEL);
@@ -777,7 +768,7 @@ static int __bch2_set_nr_journal_buckets(struct bch_dev *ca, unsigned nr,
 	new_bucket_seq	= kcalloc(nr, sizeof(u64), GFP_KERNEL);
 	if (!bu || !ob || !new_buckets || !new_bucket_seq) {
 		ret = -ENOMEM;
-		goto err_unblock;
+		goto err_free;
 	}
 
 	for (nr_got = 0; nr_got < nr_want; nr_got++) {
@@ -794,87 +785,92 @@ static int __bch2_set_nr_journal_buckets(struct bch_dev *ca, unsigned nr,
 			if (ret)
 				break;
 
+			ret = bch2_trans_run(c,
+				bch2_trans_mark_metadata_bucket(&trans, ca,
+						ob[nr_got]->bucket, BCH_DATA_journal,
+						ca->mi.bucket_size));
+			if (ret) {
+				bch2_open_bucket_put(c, ob[nr_got]);
+				bch_err(c, "error marking new journal buckets: %s", bch2_err_str(ret));
+				break;
+			}
+
 			bu[nr_got] = ob[nr_got]->bucket;
 		}
 	}
 
 	if (!nr_got)
-		goto err_unblock;
+		goto err_free;
 
-	/*
-	 * We may be called from the device add path, before the new device has
-	 * actually been added to the running filesystem:
-	 */
-	if (!new_fs)
-		spin_lock(&c->journal.lock);
+	/* Don't return an error if we successfully allocated some buckets: */
+	ret = 0;
+
+	if (c) {
+		bch2_journal_flush_all_pins(&c->journal);
+		bch2_journal_block(&c->journal);
+		mutex_lock(&c->sb_lock);
+	}
 
 	memcpy(new_buckets,	ja->buckets,	ja->nr * sizeof(u64));
 	memcpy(new_bucket_seq,	ja->bucket_seq,	ja->nr * sizeof(u64));
-	swap(new_buckets,	ja->buckets);
-	swap(new_bucket_seq,	ja->bucket_seq);
+
+	BUG_ON(ja->discard_idx > ja->nr);
+
+	pos = ja->discard_idx ?: ja->nr;
+
+	memmove(new_buckets + pos + nr_got,
+		new_buckets + pos,
+		sizeof(new_buckets[0]) * (ja->nr - pos));
+	memmove(new_bucket_seq + pos + nr_got,
+		new_bucket_seq + pos,
+		sizeof(new_bucket_seq[0]) * (ja->nr - pos));
 
 	for (i = 0; i < nr_got; i++) {
-		unsigned pos = ja->discard_idx ?: ja->nr;
-		long b = bu[i];
-
-		__array_insert_item(ja->buckets,		ja->nr, pos);
-		__array_insert_item(ja->bucket_seq,		ja->nr, pos);
-		ja->nr++;
-
-		ja->buckets[pos] = b;
-		ja->bucket_seq[pos] = 0;
-
-		if (pos <= ja->discard_idx)
-			ja->discard_idx = (ja->discard_idx + 1) % ja->nr;
-		if (pos <= ja->dirty_idx_ondisk)
-			ja->dirty_idx_ondisk = (ja->dirty_idx_ondisk + 1) % ja->nr;
-		if (pos <= ja->dirty_idx)
-			ja->dirty_idx = (ja->dirty_idx + 1) % ja->nr;
-		if (pos <= ja->cur_idx)
-			ja->cur_idx = (ja->cur_idx + 1) % ja->nr;
+		new_buckets[pos + i] = bu[i];
+		new_bucket_seq[pos + i] = 0;
 	}
 
-	ret = bch2_journal_buckets_to_sb(c, ca);
-	if (ret) {
-		/* Revert: */
-		swap(new_buckets,	ja->buckets);
-		swap(new_bucket_seq,	ja->bucket_seq);
-		ja->nr			= old_nr;
-		ja->discard_idx		= old_discard_idx;
-		ja->dirty_idx_ondisk	= old_dirty_idx_ondisk;
-		ja->dirty_idx		= old_dirty_idx;
-		ja->cur_idx		= old_cur_idx;
-	}
+	nr = ja->nr + nr_got;
 
-	if (!new_fs)
-		spin_unlock(&c->journal.lock);
+	ret = bch2_journal_buckets_to_sb(c, ca, new_buckets, nr);
+	if (ret)
+		goto err_unblock;
 
-	if (ja->nr != old_nr && !new_fs)
+	if (!new_fs)
 		bch2_write_super(c);
 
+	/* Commit: */
 	if (c)
-		bch2_journal_unblock(&c->journal);
+		spin_lock(&c->journal.lock);
 
-	if (ret)
-		goto err;
+	swap(new_buckets,	ja->buckets);
+	swap(new_bucket_seq,	ja->bucket_seq);
+	ja->nr = nr;
+
+	if (pos <= ja->discard_idx)
+		ja->discard_idx = (ja->discard_idx + nr_got) % ja->nr;
+	if (pos <= ja->dirty_idx_ondisk)
+		ja->dirty_idx_ondisk = (ja->dirty_idx_ondisk + nr_got) % ja->nr;
+	if (pos <= ja->dirty_idx)
+		ja->dirty_idx = (ja->dirty_idx + nr_got) % ja->nr;
+	if (pos <= ja->cur_idx)
+		ja->cur_idx = (ja->cur_idx + nr_got) % ja->nr;
 
-	if (!new_fs) {
-		for (i = 0; i < nr_got; i++) {
-			ret = bch2_trans_run(c,
-				bch2_trans_mark_metadata_bucket(&trans, ca,
-						bu[i], BCH_DATA_journal,
-						ca->mi.bucket_size));
-			if (ret) {
-				bch2_fs_inconsistent(c, "error marking new journal buckets: %i", ret);
-				goto err;
-			}
-		}
-	}
-err:
 	if (c)
+		spin_unlock(&c->journal.lock);
+err_unblock:
+	if (c) {
+		bch2_journal_unblock(&c->journal);
 		mutex_unlock(&c->sb_lock);
+	}
 
-	if (ob && !new_fs)
+	if (ret && !new_fs)
+		for (i = 0; i < nr_got; i++)
+			bch2_trans_run(c,
+				bch2_trans_mark_metadata_bucket(&trans, ca,
+						bu[i], BCH_DATA_free, 0));
+err_free:
+	if (!new_fs)
 		for (i = 0; i < nr_got; i++)
 			bch2_open_bucket_put(c, ob[i]);
 
@@ -882,12 +878,7 @@ static int __bch2_set_nr_journal_buckets(struct bch_dev *ca, unsigned nr,
 	kfree(new_buckets);
 	kfree(ob);
 	kfree(bu);
-
 	return ret;
-err_unblock:
-	if (c)
-		bch2_journal_unblock(&c->journal);
-	goto err;
 }
 
 /*
@@ -901,13 +892,15 @@ int bch2_set_nr_journal_buckets(struct bch_fs *c, struct bch_dev *ca,
 	struct closure cl;
 	int ret = 0;
 
+	closure_init_stack(&cl);
+
+	down_write(&c->state_lock);
+
 	/* don't handle reducing nr of buckets yet: */
 	if (nr < ja->nr)
-		return 0;
-
-	closure_init_stack(&cl);
+		goto unlock;
 
-	while (ja->nr != nr) {
+	while (ja->nr < nr) {
 		struct disk_reservation disk_res = { 0, 0 };
 
 		/*
@@ -938,7 +931,8 @@ int bch2_set_nr_journal_buckets(struct bch_fs *c, struct bch_dev *ca,
 
 	if (ret)
 		bch_err(c, "%s: err %s", __func__, bch2_err_str(ret));
-
+unlock:
+	up_write(&c->state_lock);
 	return ret;
 }
 

fs/bcachefs/journal_sb.c

@@ -175,46 +175,45 @@ const struct bch_sb_field_ops bch_sb_field_ops_journal_v2 = {
 	.to_text	= bch2_sb_journal_v2_to_text,
 };
 
-int bch2_journal_buckets_to_sb(struct bch_fs *c, struct bch_dev *ca)
+int bch2_journal_buckets_to_sb(struct bch_fs *c, struct bch_dev *ca,
+			       u64 *buckets, unsigned nr)
 {
-	struct journal_device *ja = &ca->journal;
 	struct bch_sb_field_journal_v2 *j;
-	unsigned i, dst = 0, nr = 1;
+	unsigned i, dst = 0, nr_compacted = 1;
 
 	if (c)
 		lockdep_assert_held(&c->sb_lock);
 
-	if (!ja->nr) {
+	if (!nr) {
 		bch2_sb_field_delete(&ca->disk_sb, BCH_SB_FIELD_journal);
 		bch2_sb_field_delete(&ca->disk_sb, BCH_SB_FIELD_journal_v2);
 		return 0;
 	}
 
-	for (i = 0; i + 1 < ja->nr; i++)
-		if (ja->buckets[i] + 1 != ja->buckets[i + 1])
-			nr++;
+	for (i = 0; i + 1 < nr; i++)
+		if (buckets[i] + 1 != buckets[i + 1])
+			nr_compacted++;
 
 	j = bch2_sb_resize_journal_v2(&ca->disk_sb,
-				 (sizeof(*j) + sizeof(j->d[0]) * nr) / sizeof(u64));
+			 (sizeof(*j) + sizeof(j->d[0]) * nr_compacted) / sizeof(u64));
 	if (!j)
 		return -BCH_ERR_ENOSPC_sb_journal;
 
 	bch2_sb_field_delete(&ca->disk_sb, BCH_SB_FIELD_journal);
 
-	j->d[dst].start = le64_to_cpu(ja->buckets[0]);
+	j->d[dst].start = le64_to_cpu(buckets[0]);
 	j->d[dst].nr	= le64_to_cpu(1);
 
-	for (i = 1; i < ja->nr; i++) {
-		if (ja->buckets[i] == ja->buckets[i - 1] + 1) {
+	for (i = 1; i < nr; i++) {
+		if (buckets[i] == buckets[i - 1] + 1) {
 			le64_add_cpu(&j->d[dst].nr, 1);
 		} else {
 			dst++;
-			j->d[dst].start = le64_to_cpu(ja->buckets[i]);
+			j->d[dst].start = le64_to_cpu(buckets[i]);
 			j->d[dst].nr	= le64_to_cpu(1);
 		}
 	}
 
-	BUG_ON(dst + 1 != nr);
-
+	BUG_ON(dst + 1 != nr_compacted);
 	return 0;
 }

fs/bcachefs/journal_sb.h

@@ -21,4 +21,4 @@ static inline unsigned bch2_sb_field_journal_v2_nr_entries(struct bch_sb_field_j
 extern const struct bch_sb_field_ops bch_sb_field_ops_journal;
 extern const struct bch_sb_field_ops bch_sb_field_ops_journal_v2;
 
-int bch2_journal_buckets_to_sb(struct bch_fs *, struct bch_dev *);
+int bch2_journal_buckets_to_sb(struct bch_fs *, struct bch_dev *, u64 *, unsigned);