linux/fs/bcachefs/disk_groups.c

// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "disk_groups.h"
#include "super-io.h"

#include <linux/sort.h>

static int group_cmp(const void *_l, const void *_r)
{
	const struct bch_disk_group *l = _l;
	const struct bch_disk_group *r = _r;

	return ((BCH_GROUP_DELETED(l) > BCH_GROUP_DELETED(r)) -
		(BCH_GROUP_DELETED(l) < BCH_GROUP_DELETED(r))) ?:
		((BCH_GROUP_PARENT(l) > BCH_GROUP_PARENT(r)) -
		 (BCH_GROUP_PARENT(l) < BCH_GROUP_PARENT(r))) ?:
		strncmp(l->label, r->label, sizeof(l->label));
}

static const char *bch2_sb_disk_groups_validate(struct bch_sb *sb,
						struct bch_sb_field *f)
{
	struct bch_sb_field_disk_groups *groups =
		field_to_type(f, disk_groups);
	struct bch_disk_group *g, *sorted = NULL;
	struct bch_sb_field_members *mi;
	struct bch_member *m;
	unsigned i, nr_groups, len;
	const char *err = NULL;

	mi		= bch2_sb_get_members(sb);
	groups		= bch2_sb_get_disk_groups(sb);
	nr_groups	= disk_groups_nr(groups);

	for (m = mi->members;
	     m < mi->members + sb->nr_devices;
	     m++) {
		unsigned g;

		if (!BCH_MEMBER_GROUP(m))
			continue;

		g = BCH_MEMBER_GROUP(m) - 1;

		if (g >= nr_groups ||
		    BCH_GROUP_DELETED(&groups->entries[g]))
			return "disk has invalid group";
	}

	if (!nr_groups)
		return NULL;

	for (g = groups->entries;
	     g < groups->entries + nr_groups;
	     g++) {
		if (BCH_GROUP_DELETED(g))
			continue;

		len = strnlen(g->label, sizeof(g->label));
		if (!len) {
			err = "group with empty label";
			goto err;
		}
	}

	sorted = kmalloc_array(nr_groups, sizeof(*sorted), GFP_KERNEL);
	if (!sorted)
		return "cannot allocate memory";

	memcpy(sorted, groups->entries, nr_groups * sizeof(*sorted));
	sort(sorted, nr_groups, sizeof(*sorted), group_cmp, NULL);

	for (i = 0; i + 1 < nr_groups; i++)
		if (!BCH_GROUP_DELETED(sorted + i) &&
		    !group_cmp(sorted + i, sorted + i + 1)) {
			err = "duplicate groups";
			goto err;
		}

	err = NULL;
err:
	kfree(sorted);
	return err;
}

static size_t bch2_sb_disk_groups_to_text(char *buf, size_t size,
					struct bch_sb *sb,
					struct bch_sb_field *f)
{
	char *out = buf, *end = buf + size;
	struct bch_sb_field_disk_groups *groups =
		field_to_type(f, disk_groups);
	struct bch_disk_group *g;
	unsigned nr_groups = disk_groups_nr(groups);

	for (g = groups->entries;
	     g < groups->entries + nr_groups;
	     g++) {
		if (g != groups->entries)
			out += scnprintf(out, end - out, " ");

		if (BCH_GROUP_DELETED(g))
			out += scnprintf(out, end - out, "[deleted]");
		else
			out += scnprintf(out, end - out,
					 "[parent %llu name %s]",
					 BCH_GROUP_PARENT(g),
					 g->label);
	}

	return out - buf;
}

const struct bch_sb_field_ops bch_sb_field_ops_disk_groups = {
	.validate	= bch2_sb_disk_groups_validate,
	.to_text	= bch2_sb_disk_groups_to_text
};

int bch2_sb_disk_groups_to_cpu(struct bch_fs *c)
{
	struct bch_sb_field_members *mi;
	struct bch_sb_field_disk_groups *groups;
	struct bch_disk_groups_cpu *cpu_g, *old_g;
	unsigned i, g, nr_groups;

	lockdep_assert_held(&c->sb_lock);

	mi		= bch2_sb_get_members(c->disk_sb.sb);
	groups		= bch2_sb_get_disk_groups(c->disk_sb.sb);
	nr_groups	= disk_groups_nr(groups);

	if (!groups)
		return 0;

	cpu_g = kzalloc(sizeof(*cpu_g) +
			sizeof(cpu_g->entries[0]) * nr_groups, GFP_KERNEL);
	if (!cpu_g)
		return -ENOMEM;

	cpu_g->nr = nr_groups;

	for (i = 0; i < nr_groups; i++) {
		struct bch_disk_group *src	= &groups->entries[i];
		struct bch_disk_group_cpu *dst	= &cpu_g->entries[i];

		dst->deleted	= BCH_GROUP_DELETED(src);
		dst->parent	= BCH_GROUP_PARENT(src);
	}

	for (i = 0; i < c->disk_sb.sb->nr_devices; i++) {
		struct bch_member *m = mi->members + i;
		struct bch_disk_group_cpu *dst =
			&cpu_g->entries[BCH_MEMBER_GROUP(m)];

		if (!bch2_member_exists(m))
			continue;

		g = BCH_MEMBER_GROUP(m);
		while (g) {
			dst = &cpu_g->entries[g - 1];
			__set_bit(i, dst->devs.d);
			g = dst->parent;
		}
	}

	old_g = rcu_dereference_protected(c->disk_groups,
				lockdep_is_held(&c->sb_lock));
	rcu_assign_pointer(c->disk_groups, cpu_g);
	if (old_g)
		kfree_rcu(old_g, rcu);

	return 0;
}

const struct bch_devs_mask *bch2_target_to_mask(struct bch_fs *c, unsigned target)
{
	struct target t = target_decode(target);

	switch (t.type) {
	case TARGET_NULL:
		return NULL;
	case TARGET_DEV: {
		struct bch_dev *ca = t.dev < c->sb.nr_devices
			? rcu_dereference(c->devs[t.dev])
			: NULL;
		return ca ? &ca->self : NULL;
	}
	case TARGET_GROUP: {
		struct bch_disk_groups_cpu *g = rcu_dereference(c->disk_groups);

		return t.group < g->nr && !g->entries[t.group].deleted
			? &g->entries[t.group].devs
			: NULL;
	}
	default:
		BUG();
	}
}

bool bch2_dev_in_target(struct bch_fs *c, unsigned dev, unsigned target)
{
	struct target t = target_decode(target);

	switch (t.type) {
	case TARGET_NULL:
		return false;
	case TARGET_DEV:
		return dev == t.dev;
	case TARGET_GROUP: {
		struct bch_disk_groups_cpu *g;
		const struct bch_devs_mask *m;
		bool ret;

		rcu_read_lock();
		g = rcu_dereference(c->disk_groups);
		m = t.group < g->nr && !g->entries[t.group].deleted
			? &g->entries[t.group].devs
			: NULL;

		ret = m ? test_bit(dev, m->d) : false;
		rcu_read_unlock();

		return ret;
	}
	default:
		BUG();
	}
}

static int __bch2_disk_group_find(struct bch_sb_field_disk_groups *groups,
				  unsigned parent,
				  const char *name, unsigned namelen)
{
	unsigned i, nr_groups = disk_groups_nr(groups);

	if (!namelen || namelen > BCH_SB_LABEL_SIZE)
		return -EINVAL;

	for (i = 0; i < nr_groups; i++) {
		struct bch_disk_group *g = groups->entries + i;

		if (BCH_GROUP_DELETED(g))
			continue;

		if (!BCH_GROUP_DELETED(g) &&
		    BCH_GROUP_PARENT(g) == parent &&
		    strnlen(g->label, sizeof(g->label)) == namelen &&
		    !memcmp(name, g->label, namelen))
			return i;
	}

	return -1;
}

static int __bch2_disk_group_add(struct bch_sb_handle *sb, unsigned parent,
				 const char *name, unsigned namelen)
{
	struct bch_sb_field_disk_groups *groups =
		bch2_sb_get_disk_groups(sb->sb);
	unsigned i, nr_groups = disk_groups_nr(groups);
	struct bch_disk_group *g;

	if (!namelen || namelen > BCH_SB_LABEL_SIZE)
		return -EINVAL;

	for (i = 0;
	     i < nr_groups && !BCH_GROUP_DELETED(&groups->entries[i]);
	     i++)
		;

	if (i == nr_groups) {
		unsigned u64s =
			(sizeof(struct bch_sb_field_disk_groups) +
			 sizeof(struct bch_disk_group) * (nr_groups + 1)) /
			sizeof(u64);

		groups = bch2_sb_resize_disk_groups(sb, u64s);
		if (!groups)
			return -ENOSPC;

		nr_groups = disk_groups_nr(groups);
	}

	BUG_ON(i >= nr_groups);

	g = &groups->entries[i];

	memcpy(g->label, name, namelen);
	if (namelen < sizeof(g->label))
		g->label[namelen] = '\0';
	SET_BCH_GROUP_DELETED(g, 0);
	SET_BCH_GROUP_PARENT(g, parent);
	SET_BCH_GROUP_DATA_ALLOWED(g, ~0);

	return i;
}

int bch2_disk_path_find(struct bch_sb_handle *sb, const char *name)
{
	struct bch_sb_field_disk_groups *groups =
		bch2_sb_get_disk_groups(sb->sb);
	int v = -1;

	do {
		const char *next = strchrnul(name, '.');
		unsigned len = next - name;

		if (*next == '.')
			next++;

		v = __bch2_disk_group_find(groups, v + 1, name, len);
		name = next;
	} while (*name && v >= 0);

	return v;
}

int bch2_disk_path_find_or_create(struct bch_sb_handle *sb, const char *name)
{
	struct bch_sb_field_disk_groups *groups;
	unsigned parent = 0;
	int v = -1;

	do {
		const char *next = strchrnul(name, '.');
		unsigned len = next - name;

		if (*next == '.')
			next++;

		groups = bch2_sb_get_disk_groups(sb->sb);

		v = __bch2_disk_group_find(groups, parent, name, len);
		if (v < 0)
			v = __bch2_disk_group_add(sb, parent, name, len);
		if (v < 0)
			return v;

		parent = v + 1;
		name = next;
	} while (*name && v >= 0);

	return v;
}

int bch2_disk_path_print(struct bch_sb_handle *sb,
			 char *buf, size_t len, unsigned v)
{
	char *out = buf, *end = out + len;
	struct bch_sb_field_disk_groups *groups =
		bch2_sb_get_disk_groups(sb->sb);
	struct bch_disk_group *g;
	unsigned nr = 0;
	u16 path[32];

	while (1) {
		if (nr == ARRAY_SIZE(path))
			goto inval;

		if (v >= disk_groups_nr(groups))
			goto inval;

		g = groups->entries + v;

		if (BCH_GROUP_DELETED(g))
			goto inval;

		path[nr++] = v;

		if (!BCH_GROUP_PARENT(g))
			break;

		v = BCH_GROUP_PARENT(g) - 1;
	}

	while (nr) {
		unsigned b = 0;

		v = path[--nr];
		g = groups->entries + v;

		if (end != out)
			b = min_t(size_t, end - out,
				  strnlen(g->label, sizeof(g->label)));
		memcpy(out, g->label, b);
		if (b < end - out)
			out[b] = '\0';
		out += b;

		if (nr)
			out += scnprintf(out, end - out, ".");
	}

	return out - buf;
inval:
	return scnprintf(buf, len, "invalid group %u", v);
}

int bch2_dev_group_set(struct bch_fs *c, struct bch_dev *ca, const char *name)
{
	struct bch_member *mi;
	int v = -1;

	mutex_lock(&c->sb_lock);

	if (!strlen(name) || !strcmp(name, "none"))
		goto write_sb;

	v = bch2_disk_path_find_or_create(&c->disk_sb, name);
	if (v < 0) {
		mutex_unlock(&c->sb_lock);
		return v;
	}

write_sb:
	mi = &bch2_sb_get_members(c->disk_sb.sb)->members[ca->dev_idx];
	SET_BCH_MEMBER_GROUP(mi, v + 1);

	bch2_write_super(c);
	mutex_unlock(&c->sb_lock);

	return 0;
}

int bch2_opt_target_parse(struct bch_fs *c, const char *buf, u64 *v)
{
	struct bch_dev *ca;
	int g;

	if (!strlen(buf) || !strcmp(buf, "none")) {
		*v = 0;
		return 0;
	}

	/* Is it a device? */
	ca = bch2_dev_lookup(c, buf);
	if (!IS_ERR(ca)) {
		*v = dev_to_target(ca->dev_idx);
		percpu_ref_put(&ca->ref);
		return 0;
	}

	mutex_lock(&c->sb_lock);
	g = bch2_disk_path_find(&c->disk_sb, buf);
	mutex_unlock(&c->sb_lock);

	if (g >= 0) {
		*v = group_to_target(g);
		return 0;
	}

	return -EINVAL;
}

int bch2_opt_target_print(struct bch_fs *c, char *buf, size_t len, u64 v)
{
	struct target t = target_decode(v);
	int ret;

	switch (t.type) {
	case TARGET_NULL:
		return scnprintf(buf, len, "none");
	case TARGET_DEV: {
		struct bch_dev *ca;

		rcu_read_lock();
		ca = t.dev < c->sb.nr_devices
			? rcu_dereference(c->devs[t.dev])
			: NULL;

		if (ca && percpu_ref_tryget(&ca->io_ref)) {
			ret = scnprintf(buf, len, "/dev/%pg",
					ca->disk_sb.bdev);
			percpu_ref_put(&ca->io_ref);
		} else if (ca) {
			ret = scnprintf(buf, len, "offline device %u", t.dev);
		} else {
			ret = scnprintf(buf, len, "invalid device %u", t.dev);
		}

		rcu_read_unlock();
		break;
	}
	case TARGET_GROUP:
		mutex_lock(&c->sb_lock);
		ret = bch2_disk_path_print(&c->disk_sb, buf, len, t.group);
		mutex_unlock(&c->sb_lock);
		break;
	default:
		BUG();
	}

	return ret;
}