bcachefs: reserve space in journal for fs usage entries

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bcachefs.h

@@ -545,6 +545,8 @@ struct bch_fs {
 	struct bch_replicas_cpu replicas_gc;
 	struct mutex		replicas_gc_lock;
 
+	struct journal_entry_res replicas_journal_res;
+
 	struct bch_disk_groups_cpu __rcu *disk_groups;
 
 	struct bch_opts		opts;

fs/bcachefs/bcachefs_format.h

@@ -1362,7 +1362,8 @@ static inline __u64 __bset_magic(struct bch_sb *sb)
 	x(btree_root,		1)		\
 	x(prio_ptrs,		2)		\
 	x(blacklist,		3)		\
-	x(blacklist_v2,		4)
+	x(blacklist_v2,		4)		\
+	x(usage,		5)
 
 enum {
 #define x(f, nr)	BCH_JSET_ENTRY_##f	= nr,
@@ -1392,6 +1393,20 @@ struct jset_entry_blacklist_v2 {
 	__le64			end;
 };
 
+enum {
+	FS_USAGE_REPLICAS		= 0,
+	FS_USAGE_INODES			= 1,
+	FS_USAGE_KEY_VERSION		= 2,
+	FS_USAGE_NR			= 3
+};
+
+struct jset_entry_usage {
+	struct jset_entry	entry;
+	__le64			sectors;
+	__u8			type;
+	struct bch_replicas_entry r;
+} __attribute__((packed));
+
 /*
  * On disk format for a journal entry:
  * seq is monotonically increasing; every journal entry has its own unique

fs/bcachefs/journal_io.c

@@ -284,6 +284,7 @@ static int journal_entry_validate_blacklist_v2(struct bch_fs *c,
 	if (journal_entry_err_on(le16_to_cpu(entry->u64s) != 2, c,
 		"invalid journal seq blacklist entry: bad size")) {
 		journal_entry_null_range(entry, vstruct_next(entry));
+		goto out;
 	}
 
 	bl_entry = container_of(entry, struct jset_entry_blacklist_v2, entry);
@@ -293,6 +294,28 @@ static int journal_entry_validate_blacklist_v2(struct bch_fs *c,
 		"invalid journal seq blacklist entry: start > end")) {
 		journal_entry_null_range(entry, vstruct_next(entry));
 	}
+out:
+fsck_err:
+	return ret;
+}
+
+static int journal_entry_validate_usage(struct bch_fs *c,
+					struct jset *jset,
+					struct jset_entry *entry,
+					int write)
+{
+	struct jset_entry_usage *u =
+		container_of(entry, struct jset_entry_usage, entry);
+	unsigned bytes = jset_u64s(le16_to_cpu(entry->u64s)) * sizeof(u64);
+	int ret = 0;
+
+	if (journal_entry_err_on(bytes < sizeof(*u) ||
+				 bytes < sizeof(*u) + u->r.nr_devs,
+				 c,
+				 "invalid journal entry usage: bad size")) {
+		journal_entry_null_range(entry, vstruct_next(entry));
+		return ret;
+	}
 
 fsck_err:
 	return ret;
@@ -315,18 +338,10 @@ static const struct jset_entry_ops bch2_jset_entry_ops[] = {
 static int journal_entry_validate(struct bch_fs *c, struct jset *jset,
 				  struct jset_entry *entry, int write)
 {
-	int ret = 0;
+	return entry->type < BCH_JSET_ENTRY_NR
-
+		? bch2_jset_entry_ops[entry->type].validate(c, jset,
-	if (entry->type >= BCH_JSET_ENTRY_NR) {
+							    entry, write)
-		journal_entry_err(c, "invalid journal entry type %u",
+		: 0;
-				  entry->type);
-		journal_entry_null_range(entry, vstruct_next(entry));
-		return 0;
-	}
-
-	ret = bch2_jset_entry_ops[entry->type].validate(c, jset, entry, write);
-fsck_err:
-	return ret;
 }
 
 static int jset_validate_entries(struct bch_fs *c, struct jset *jset,

fs/bcachefs/recovery.c

@@ -108,7 +108,8 @@ static bool journal_empty(struct list_head *journal)
 
 	list_for_each_entry(i, journal, list) {
 		vstruct_for_each(&i->j, entry) {
-			if (entry->type == BCH_JSET_ENTRY_btree_root)
+			if (entry->type == BCH_JSET_ENTRY_btree_root ||
+			    entry->type == BCH_JSET_ENTRY_usage)
 				continue;
 
 			if (entry->type == BCH_JSET_ENTRY_btree_keys &&

fs/bcachefs/replicas.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 
 #include "bcachefs.h"
+#include "journal.h"
 #include "replicas.h"
 #include "super-io.h"
 
@@ -302,6 +303,27 @@ err:
 	return ret;
 }
 
+static unsigned reserve_journal_replicas(struct bch_fs *c,
+				     struct bch_replicas_cpu *r)
+{
+	struct bch_replicas_entry *e;
+	unsigned journal_res_u64s = 0;
+
+	/* nr_inodes: */
+	journal_res_u64s +=
+		DIV_ROUND_UP(sizeof(struct jset_entry_usage), sizeof(u64));
+
+	/* key_version: */
+	journal_res_u64s +=
+		DIV_ROUND_UP(sizeof(struct jset_entry_usage), sizeof(u64));
+
+	for_each_cpu_replicas_entry(r, e)
+		journal_res_u64s +=
+			DIV_ROUND_UP(sizeof(struct jset_entry_usage) +
+				     e->nr_devs, sizeof(u64));
+	return journal_res_u64s;
+}
+
 noinline
 static int bch2_mark_replicas_slowpath(struct bch_fs *c,
 				struct bch_replicas_entry *new_entry)
@@ -329,6 +351,10 @@ static int bch2_mark_replicas_slowpath(struct bch_fs *c,
 		ret = bch2_cpu_replicas_to_sb_replicas(c, &new_r);
 		if (ret)
 			goto err;
+
+		bch2_journal_entry_res_resize(&c->journal,
+				&c->replicas_journal_res,
+				reserve_journal_replicas(c, &new_r));
 	}
 
 	if (!new_r.entries &&
@@ -595,6 +621,7 @@ int bch2_sb_replicas_to_cpu_replicas(struct bch_fs *c)
 	bch2_cpu_replicas_sort(&new_r);
 
 	percpu_down_write(&c->mark_lock);
+
 	ret = replicas_table_update(c, &new_r);
 	percpu_up_write(&c->mark_lock);
 
@@ -915,3 +942,10 @@ unsigned bch2_dev_has_data(struct bch_fs *c, struct bch_dev *ca)
 
 	return ret;
 }
+
+int bch2_fs_replicas_init(struct bch_fs *c)
+{
+	c->journal.entry_u64s_reserved +=
+		reserve_journal_replicas(c, &c->replicas);
+	return 0;
+}

fs/bcachefs/replicas.h

@@ -80,4 +80,6 @@ int bch2_sb_replicas_to_cpu_replicas(struct bch_fs *);
 extern const struct bch_sb_field_ops bch_sb_field_ops_replicas;
 extern const struct bch_sb_field_ops bch_sb_field_ops_replicas_v0;
 
+int bch2_fs_replicas_init(struct bch_fs *);
+
 #endif /* _BCACHEFS_REPLICAS_H */

fs/bcachefs/super.c

@@ -658,6 +658,7 @@ static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts)
 	    bch2_io_clock_init(&c->io_clock[READ]) ||
 	    bch2_io_clock_init(&c->io_clock[WRITE]) ||
 	    bch2_fs_journal_init(&c->journal) ||
+	    bch2_fs_replicas_init(c) ||
 	    bch2_fs_btree_cache_init(c) ||
 	    bch2_fs_io_init(c) ||
 	    bch2_fs_encryption_init(c) ||