Merge tag 'bcachefs-2025-03-06' of git://evilpiepirate.org/bcachefs

Pull bcachefs fixes from Kent Overstreet:

 - Fix a compatibility issue: we shouldn't be setting incompat feature
   bits unless explicitly requested

 - Fix another bug where the journal alloc/resize path could spuriously
   fail with -BCH_ERR_open_buckets_empty

 - Copygc shouldn't run on read-only devices: fragmentation isn't an
   issue if we're not currently writing to a given device, and it may
   not have anywhere to move the data to

* tag 'bcachefs-2025-03-06' of git://evilpiepirate.org/bcachefs:
  bcachefs: copygc now skips non-rw devices
  bcachefs: Fix bch2_dev_journal_alloc() spuriously failing
  bcachefs: Don't set BCH_FEATURE_incompat_version_field unless requested

Author: torvalds

fs/bcachefs/journal.c

@@ -1021,8 +1021,8 @@ struct journal_buf *bch2_next_write_buffer_flush_journal_buf(struct journal *j,
 
 /* allocate journal on a device: */
 
-static int __bch2_set_nr_journal_buckets(struct bch_dev *ca, unsigned nr,
-					 bool new_fs, struct closure *cl)
+static int bch2_set_nr_journal_buckets_iter(struct bch_dev *ca, unsigned nr,
+					    bool new_fs, struct closure *cl)
 {
 	struct bch_fs *c = ca->fs;
 	struct journal_device *ja = &ca->journal;
@@ -1150,26 +1150,20 @@ static int __bch2_set_nr_journal_buckets(struct bch_dev *ca, unsigned nr,
 	return ret;
 }
 
-/*
- * Allocate more journal space at runtime - not currently making use if it, but
- * the code works:
- */
-int bch2_set_nr_journal_buckets(struct bch_fs *c, struct bch_dev *ca,
-				unsigned nr)
+static int bch2_set_nr_journal_buckets_loop(struct bch_fs *c, struct bch_dev *ca,
+					    unsigned nr, bool new_fs)
 {
 	struct journal_device *ja = &ca->journal;
-	struct closure cl;
 	int ret = 0;
 
+	struct closure cl;
 	closure_init_stack(&cl);
 
-	down_write(&c->state_lock);
-
 	/* don't handle reducing nr of buckets yet: */
 	if (nr < ja->nr)
-		goto unlock;
+		return 0;
 
-	while (ja->nr < nr) {
+	while (!ret && ja->nr < nr) {
 		struct disk_reservation disk_res = { 0, 0, 0 };
 
 		/*
@@ -1182,27 +1176,38 @@ int bch2_set_nr_journal_buckets(struct bch_fs *c, struct bch_dev *ca,
 		 * filesystem-wide allocation will succeed, this is a device
 		 * specific allocation - we can hang here:
 		 */
+		if (!new_fs) {
+			ret = bch2_disk_reservation_get(c, &disk_res,
+							bucket_to_sector(ca, nr - ja->nr), 1, 0);
+			if (ret)
+				break;
+		}
 
-		ret = bch2_disk_reservation_get(c, &disk_res,
-						bucket_to_sector(ca, nr - ja->nr), 1, 0);
-		if (ret)
-			break;
+		ret = bch2_set_nr_journal_buckets_iter(ca, nr, new_fs, &cl);
 
-		ret = __bch2_set_nr_journal_buckets(ca, nr, false, &cl);
+		if (ret == -BCH_ERR_bucket_alloc_blocked ||
+		    ret == -BCH_ERR_open_buckets_empty)
+			ret = 0; /* wait and retry */
 
 		bch2_disk_reservation_put(c, &disk_res);
-
 		closure_sync(&cl);
-
-		if (ret &&
-		    ret != -BCH_ERR_bucket_alloc_blocked &&
-		    ret != -BCH_ERR_open_buckets_empty)
-			break;
 	}
 
-	bch_err_fn(c, ret);
-unlock:
+	return ret;
+}
+
+/*
+ * Allocate more journal space at runtime - not currently making use if it, but
+ * the code works:
+ */
+int bch2_set_nr_journal_buckets(struct bch_fs *c, struct bch_dev *ca,
+				unsigned nr)
+{
+	down_write(&c->state_lock);
+	int ret = bch2_set_nr_journal_buckets_loop(c, ca, nr, false);
 	up_write(&c->state_lock);
+
+	bch_err_fn(c, ret);
 	return ret;
 }
 
@@ -1228,7 +1233,7 @@ int bch2_dev_journal_alloc(struct bch_dev *ca, bool new_fs)
 		     min(1 << 13,
 			 (1 << 24) / ca->mi.bucket_size));
 
-	ret = __bch2_set_nr_journal_buckets(ca, nr, new_fs, NULL);
+	ret = bch2_set_nr_journal_buckets_loop(ca->fs, ca, nr, new_fs);
 err:
 	bch_err_fn(ca, ret);
 	return ret;

fs/bcachefs/movinggc.c

@@ -74,34 +74,33 @@ static int bch2_bucket_is_movable(struct btree_trans *trans,
 				  struct move_bucket *b, u64 time)
 {
 	struct bch_fs *c = trans->c;
-	struct btree_iter iter;
-	struct bkey_s_c k;
-	struct bch_alloc_v4 _a;
-	const struct bch_alloc_v4 *a;
-	int ret;
 
-	if (bch2_bucket_is_open(trans->c,
-				b->k.bucket.inode,
-				b->k.bucket.offset))
+	if (bch2_bucket_is_open(c, b->k.bucket.inode, b->k.bucket.offset))
 		return 0;
 
-	k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_alloc,
-			       b->k.bucket, BTREE_ITER_cached);
-	ret = bkey_err(k);
+	struct btree_iter iter;
+	struct bkey_s_c k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_alloc,
+				       b->k.bucket, BTREE_ITER_cached);
+	int ret = bkey_err(k);
 	if (ret)
 		return ret;
 
 	struct bch_dev *ca = bch2_dev_tryget(c, k.k->p.inode);
 	if (!ca)
 		goto out;
 
-	a = bch2_alloc_to_v4(k, &_a);
+	if (ca->mi.state != BCH_MEMBER_STATE_rw ||
+	    !bch2_dev_is_online(ca))
+		goto out_put;
+
+	struct bch_alloc_v4 _a;
+	const struct bch_alloc_v4 *a = bch2_alloc_to_v4(k, &_a);
 	b->k.gen	= a->gen;
 	b->sectors	= bch2_bucket_sectors_dirty(*a);
 	u64 lru_idx	= alloc_lru_idx_fragmentation(*a, ca);
 
 	ret = lru_idx && lru_idx <= time;
-
+out_put:
 	bch2_dev_put(ca);
 out:
 	bch2_trans_iter_exit(trans, &iter);

fs/bcachefs/super-io.c

@@ -69,14 +69,20 @@ enum bcachefs_metadata_version bch2_latest_compatible_version(enum bcachefs_meta
 	return v;
 }
 
-void bch2_set_version_incompat(struct bch_fs *c, enum bcachefs_metadata_version version)
+bool bch2_set_version_incompat(struct bch_fs *c, enum bcachefs_metadata_version version)
 {
-	mutex_lock(&c->sb_lock);
-	SET_BCH_SB_VERSION_INCOMPAT(c->disk_sb.sb,
-		max(BCH_SB_VERSION_INCOMPAT(c->disk_sb.sb), version));
-	c->disk_sb.sb->features[0] |= cpu_to_le64(BCH_FEATURE_incompat_version_field);
-	bch2_write_super(c);
-	mutex_unlock(&c->sb_lock);
+	bool ret = (c->sb.features & BIT_ULL(BCH_FEATURE_incompat_version_field)) &&
+		   version <= c->sb.version_incompat_allowed;
+
+	if (ret) {
+		mutex_lock(&c->sb_lock);
+		SET_BCH_SB_VERSION_INCOMPAT(c->disk_sb.sb,
+			max(BCH_SB_VERSION_INCOMPAT(c->disk_sb.sb), version));
+		bch2_write_super(c);
+		mutex_unlock(&c->sb_lock);
+	}
+
+	return ret;
 }
 
 const char * const bch2_sb_fields[] = {
@@ -1219,9 +1225,11 @@ void bch2_sb_upgrade(struct bch_fs *c, unsigned new_version, bool incompat)
 	c->disk_sb.sb->version = cpu_to_le16(new_version);
 	c->disk_sb.sb->features[0] |= cpu_to_le64(BCH_SB_FEATURES_ALL);
 
-	if (incompat)
+	if (incompat) {
 		SET_BCH_SB_VERSION_INCOMPAT_ALLOWED(c->disk_sb.sb,
 			max(BCH_SB_VERSION_INCOMPAT_ALLOWED(c->disk_sb.sb), new_version));
+		c->disk_sb.sb->features[0] |= cpu_to_le64(BCH_FEATURE_incompat_version_field);
+	}
 }
 
 static int bch2_sb_ext_validate(struct bch_sb *sb, struct bch_sb_field *f,

fs/bcachefs/super-io.h

@@ -21,17 +21,14 @@ static inline bool bch2_version_compatible(u16 version)
 void bch2_version_to_text(struct printbuf *, enum bcachefs_metadata_version);
 enum bcachefs_metadata_version bch2_latest_compatible_version(enum bcachefs_metadata_version);
 
-void bch2_set_version_incompat(struct bch_fs *, enum bcachefs_metadata_version);
+bool bch2_set_version_incompat(struct bch_fs *, enum bcachefs_metadata_version);
 
 static inline bool bch2_request_incompat_feature(struct bch_fs *c,
 						 enum bcachefs_metadata_version version)
 {
-	if (unlikely(version > c->sb.version_incompat)) {
-		if (version > c->sb.version_incompat_allowed)
-			return false;
-		bch2_set_version_incompat(c, version);
-	}
-	return true;
+	return likely(version <= c->sb.version_incompat)
+		? true
+		: bch2_set_version_incompat(c, version);
 }
 
 static inline size_t bch2_sb_field_bytes(struct bch_sb_field *f)