bcachefs: bch2_check_alloc_key() -> bch2_dev_tryget_noerror()

More elimination of bch2_dev_bkey_exists() usage.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/alloc_background.c

@@ -1024,24 +1024,25 @@ int bch2_check_alloc_key(struct btree_trans *trans,
 			 struct btree_iter *bucket_gens_iter)
 {
 	struct bch_fs *c = trans->c;
-	struct bch_dev *ca;
 	struct bch_alloc_v4 a_convert;
 	const struct bch_alloc_v4 *a;
 	unsigned discard_key_type, freespace_key_type;
 	unsigned gens_offset;
 	struct bkey_s_c k;
 	struct printbuf buf = PRINTBUF;
-	int ret;
+	int ret = 0;
 
-	if (fsck_err_on(!bch2_dev_bucket_exists(c, alloc_k.k->p), c,
-			alloc_key_to_missing_dev_bucket,
+	struct bch_dev *ca = bch2_dev_bucket_tryget_noerror(c, alloc_k.k->p);
+	if (fsck_err_on(!ca,
+			c, alloc_key_to_missing_dev_bucket,
 			"alloc key for invalid device:bucket %llu:%llu",
 			alloc_k.k->p.inode, alloc_k.k->p.offset))
-		return bch2_btree_delete_at(trans, alloc_iter, 0);
+		ret = bch2_btree_delete_at(trans, alloc_iter, 0);
+	if (!ca)
+		return ret;
 
-	ca = bch2_dev_bkey_exists(c, alloc_k.k->p.inode);
 	if (!ca->mi.freespace_initialized)
-		return 0;
+		goto out;
 
 	a = bch2_alloc_to_v4(alloc_k, &a_convert);
 
@@ -1140,8 +1141,10 @@ int bch2_check_alloc_key(struct btree_trans *trans,
 		if (ret)
 			goto err;
 	}
+out:
 err:
 fsck_err:
+	bch2_dev_put(ca);
 	printbuf_exit(&buf);
 	return ret;
 }

fs/bcachefs/buckets.h

@@ -35,11 +35,6 @@ static inline u64 sector_to_bucket_and_offset(const struct bch_dev *ca, sector_t
 	return div_u64_rem(s, ca->mi.bucket_size, offset);
 }
 
-static inline bool bucket_valid(const struct bch_dev *ca, u64 b)
-{
-	return b - ca->mi.first_bucket < ca->mi.nbuckets_minus_first;
-}
-
 #define for_each_bucket(_b, _buckets)				\
 	for (_b = (_buckets)->b + (_buckets)->first_bucket;	\
 	     _b < (_buckets)->b + (_buckets)->nbuckets; _b++)

fs/bcachefs/sb-members.c

@@ -14,6 +14,11 @@ void bch2_dev_missing(struct bch_fs *c, unsigned dev)
 	bch2_fs_inconsistent(c, "pointer to nonexistent device %u", dev);
 }
 
+void bch2_dev_bucket_missing(struct bch_fs *c, struct bpos bucket)
+{
+	bch2_fs_inconsistent(c, "pointer to nonexistent bucket %llu:%llu", bucket.inode, bucket.offset);
+}
+
 #define x(t, n, ...) [n] = #t,
 static const char * const bch2_iops_measurements[] = {
 	BCH_IOPS_MEASUREMENTS()

fs/bcachefs/sb-members.h

@@ -190,6 +190,11 @@ static inline bool bch2_dev_exists(const struct bch_fs *c, unsigned dev)
 	return dev < c->sb.nr_devices && c->devs[dev];
 }
 
+static inline bool bucket_valid(const struct bch_dev *ca, u64 b)
+{
+	return b - ca->mi.first_bucket < ca->mi.nbuckets_minus_first;
+}
+
 /*
  * If a key exists that references a device, the device won't be going away and
  * we can omit rcu_read_lock():
@@ -237,6 +242,26 @@ static inline struct bch_dev *bch2_dev_tryget(struct bch_fs *c, unsigned dev)
 	return ca;
 }
 
+static inline struct bch_dev *bch2_dev_bucket_tryget_noerror(struct bch_fs *c, struct bpos bucket)
+{
+	struct bch_dev *ca = bch2_dev_tryget_noerror(c, bucket.inode);
+	if (ca && !bucket_valid(ca, bucket.offset)) {
+		bch2_dev_put(ca);
+		ca = NULL;
+	}
+	return ca;
+}
+
+void bch2_dev_bucket_missing(struct bch_fs *, struct bpos);
+
+static inline struct bch_dev *bch2_dev_bucket_tryget(struct bch_fs *c, struct bpos bucket)
+{
+	struct bch_dev *ca = bch2_dev_bucket_tryget_noerror(c, bucket);
+	if (!ca)
+		bch2_dev_bucket_missing(c, bucket);
+	return ca;
+}
+
 /* XXX kill, move to struct bch_fs */
 static inline struct bch_devs_mask bch2_online_devs(struct bch_fs *c)
 {