bcachefs: Don't restrict copygc writes to the same device

This no longer makes any sense, since copygc is now one thread per
filesystem, not per device, with a single write point.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/alloc_foreground.c

@@ -70,12 +70,6 @@
 #include <linux/rculist.h>
 #include <linux/rcupdate.h>
 
-enum bucket_alloc_ret {
-	ALLOC_SUCCESS,
-	OPEN_BUCKETS_EMPTY,
-	FREELIST_EMPTY,		/* Allocator thread not keeping up */
-};
-
 /*
  * Open buckets represent a bucket that's currently being allocated from.  They
  * serve two purposes:
@@ -395,7 +389,8 @@ static void add_new_bucket(struct bch_fs *c,
 	ob_push(c, ptrs, ob);
 }
 
-int bch2_bucket_alloc_set(struct bch_fs *c,
+enum bucket_alloc_ret
+bch2_bucket_alloc_set(struct bch_fs *c,
 		      struct open_buckets *ptrs,
 		      struct dev_stripe_state *stripe,
 		      struct bch_devs_mask *devs_may_alloc,
@@ -409,7 +404,7 @@ int bch2_bucket_alloc_set(struct bch_fs *c,
 	struct dev_alloc_list devs_sorted =
 		bch2_dev_alloc_list(c, stripe, devs_may_alloc);
 	struct bch_dev *ca;
-	bool alloc_failure = false;
+	enum bucket_alloc_ret ret = INSUFFICIENT_DEVICES;
 	unsigned i;
 
 	BUG_ON(*nr_effective >= nr_replicas);
@@ -427,16 +422,10 @@ int bch2_bucket_alloc_set(struct bch_fs *c,
 		ob = bch2_bucket_alloc(c, ca, reserve,
 				flags & BUCKET_MAY_ALLOC_PARTIAL, cl);
 		if (IS_ERR(ob)) {
-			enum bucket_alloc_ret ret = -PTR_ERR(ob);
-
-			WARN_ON(reserve == RESERVE_MOVINGGC &&
-				ret != OPEN_BUCKETS_EMPTY);
+			ret = -PTR_ERR(ob);
 
 			if (cl)
-				return -EAGAIN;
-			if (ret == OPEN_BUCKETS_EMPTY)
-				return -ENOSPC;
-			alloc_failure = true;
+				return ret;
 			continue;
 		}
 
@@ -446,10 +435,10 @@ int bch2_bucket_alloc_set(struct bch_fs *c,
 		bch2_dev_stripe_increment(c, ca, stripe);
 
 		if (*nr_effective >= nr_replicas)
-			return 0;
+			return ALLOC_SUCCESS;
 	}
 
-	return alloc_failure ? -ENOSPC : -EROFS;
+	return ret;
 }
 
 /* Allocate from stripes: */
@@ -546,7 +535,8 @@ static void get_buckets_from_writepoint(struct bch_fs *c,
 	wp->ptrs = ptrs_skip;
 }
 
-static int open_bucket_add_buckets(struct bch_fs *c,
+static enum bucket_alloc_ret
+open_bucket_add_buckets(struct bch_fs *c,
 			struct open_buckets *ptrs,
 			struct write_point *wp,
 			struct bch_devs_list *devs_have,
@@ -562,8 +552,8 @@ static int open_bucket_add_buckets(struct bch_fs *c,
 	struct bch_devs_mask devs;
 	struct open_bucket *ob;
 	struct closure *cl = NULL;
+	enum bucket_alloc_ret ret;
 	unsigned i;
-	int ret;
 
 	rcu_read_lock();
 	devs = target_rw_devs(c, wp->type, target);
@@ -608,7 +598,7 @@ static int open_bucket_add_buckets(struct bch_fs *c,
 	ret = bch2_bucket_alloc_set(c, ptrs, &wp->stripe, &devs,
 				nr_replicas, nr_effective, have_cache,
 				reserve, flags, cl);
-	if (ret && ret != -EROFS && !cl && _cl) {
+	if (ret && ret != INSUFFICIENT_DEVICES && !cl && _cl) {
 		cl = _cl;
 		goto retry_blocking;
 	}
@@ -799,7 +789,8 @@ struct write_point *bch2_alloc_sectors_start(struct bch_fs *c,
 	unsigned nr_effective, write_points_nr;
 	unsigned ob_flags = 0;
 	bool have_cache;
-	int ret, i;
+	enum bucket_alloc_ret ret;
+	int i;
 
 	if (!(flags & BCH_WRITE_ONLY_SPECIFIED_DEVS))
 		ob_flags |= BUCKET_ALLOC_USE_DURABILITY;
@@ -844,10 +835,13 @@ struct write_point *bch2_alloc_sectors_start(struct bch_fs *c,
 alloc_done:
 	BUG_ON(!ret && nr_effective < nr_replicas);
 
+	WARN_ON(reserve == RESERVE_MOVINGGC &&
+		ret == FREELIST_EMPTY);
+
 	if (erasure_code && !ec_open_bucket(c, &ptrs))
 		pr_debug("failed to get ec bucket: ret %u", ret);
 
-	if (ret == -EROFS &&
+	if (ret == INSUFFICIENT_DEVICES &&
 	    nr_effective >= nr_replicas_required)
 		ret = 0;
 
@@ -881,11 +875,19 @@ struct write_point *bch2_alloc_sectors_start(struct bch_fs *c,
 
 	mutex_unlock(&wp->lock);
 
-	if (ret == -ENOSPC &&
+	if (ret == FREELIST_EMPTY &&
 	    try_decrease_writepoints(c, write_points_nr))
 		goto retry;
 
-	return ERR_PTR(ret);
+	switch (ret) {
+	case OPEN_BUCKETS_EMPTY:
+	case FREELIST_EMPTY:
+		return cl ? ERR_PTR(-EAGAIN) : ERR_PTR(-ENOSPC);
+	case INSUFFICIENT_DEVICES:
+		return ERR_PTR(-EROFS);
+	default:
+		BUG();
+	}
 }
 
 /*

fs/bcachefs/alloc_foreground.h

@@ -12,6 +12,13 @@ struct bch_dev;
 struct bch_fs;
 struct bch_devs_List;
 
+enum bucket_alloc_ret {
+	ALLOC_SUCCESS,
+	OPEN_BUCKETS_EMPTY,
+	FREELIST_EMPTY,		/* Allocator thread not keeping up */
+	INSUFFICIENT_DEVICES,
+};
+
 struct dev_alloc_list {
 	unsigned	nr;
 	u8		devs[BCH_SB_MEMBERS_MAX];
@@ -92,7 +99,8 @@ static inline void bch2_open_bucket_get(struct bch_fs *c,
 	}
 }
 
-int bch2_bucket_alloc_set(struct bch_fs *, struct open_buckets *,
+enum bucket_alloc_ret
+bch2_bucket_alloc_set(struct bch_fs *, struct open_buckets *,
 		      struct dev_stripe_state *, struct bch_devs_mask *,
 		      unsigned, unsigned *, bool *, enum alloc_reserve,
 		      unsigned, struct closure *);

fs/bcachefs/move.c

@@ -246,11 +246,14 @@ int bch2_migrate_write_init(struct bch_fs *c, struct migrate_write *m,
 	m->op.target	= data_opts.target,
 	m->op.write_point = wp;
 
-	if (m->data_opts.btree_insert_flags & BTREE_INSERT_USE_RESERVE)
+	if (m->data_opts.btree_insert_flags & BTREE_INSERT_USE_RESERVE) {
 		m->op.alloc_reserve = RESERVE_MOVINGGC;
+	} else {
+		/* XXX: this should probably be passed in */
+		m->op.flags |= BCH_WRITE_ONLY_SPECIFIED_DEVS;
+	}
 
-	m->op.flags |= BCH_WRITE_ONLY_SPECIFIED_DEVS|
-		BCH_WRITE_PAGES_STABLE|
+	m->op.flags |= BCH_WRITE_PAGES_STABLE|
 		BCH_WRITE_PAGES_OWNED|
 		BCH_WRITE_DATA_ENCODED|
 		BCH_WRITE_FROM_INTERNAL;

fs/bcachefs/movinggc.c

@@ -105,7 +105,7 @@ static enum data_cmd copygc_pred(struct bch_fs *c, void *arg,
 		return DATA_SKIP;
 
 	/* XXX: use io_opts for this inode */
-	data_opts->target		= dev_to_target(dev_idx);
+	data_opts->target		= io_opts->background_target;
 	data_opts->btree_insert_flags	= BTREE_INSERT_USE_RESERVE;
 	data_opts->rewrite_dev		= dev_idx;
 	return DATA_REWRITE;