btrfs: publish allocation data in sysfs

While trying to debug ENOSPC issues, it's helpful to understand what the
kernel's view of the available space is. We export this information
via ioctl, but sysfs files are more easily used.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 148 insertions, 0 deletions

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 562e346994d9..e060958a6382 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -219,6 +219,140 @@ static const struct attribute_group btrfs_feature_attr_group = {
 	.attrs = btrfs_supported_feature_attrs,
 };
 
+static ssize_t btrfs_show_u64(u64 *value_ptr, spinlock_t *lock, char *buf)
+{
+	u64 val;
+	if (lock)
+		spin_lock(lock);
+	val = *value_ptr;
+	if (lock)
+		spin_unlock(lock);
+	return snprintf(buf, PAGE_SIZE, "%llu\n", val);
+}
+
+static ssize_t global_rsv_size_show(struct kobject *kobj,
+				    struct kobj_attribute *ka, char *buf)
+{
+	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
+	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
+	return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
+}
+BTRFS_ATTR(global_rsv_size, 0444, global_rsv_size_show);
+
+static ssize_t global_rsv_reserved_show(struct kobject *kobj,
+					struct kobj_attribute *a, char *buf)
+{
+	struct btrfs_fs_info *fs_info = to_fs_info(kobj->parent);
+	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
+	return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
+}
+BTRFS_ATTR(global_rsv_reserved, 0444, global_rsv_reserved_show);
+
+#define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
+
+static ssize_t raid_bytes_show(struct kobject *kobj,
+			       struct kobj_attribute *attr, char *buf);
+BTRFS_RAID_ATTR(total_bytes, raid_bytes_show);
+BTRFS_RAID_ATTR(used_bytes, raid_bytes_show);
+
+static ssize_t raid_bytes_show(struct kobject *kobj,
+			       struct kobj_attribute *attr, char *buf)
+
+{
+	struct btrfs_space_info *sinfo = to_space_info(kobj->parent);
+	struct btrfs_block_group_cache *block_group;
+	int index = kobj - sinfo->block_group_kobjs;
+	u64 val = 0;
+
+	down_read(&sinfo->groups_sem);
+	list_for_each_entry(block_group, &sinfo->block_groups[index], list) {
+		if (&attr->attr == BTRFS_RAID_ATTR_PTR(total_bytes))
+			val += block_group->key.offset;
+		else
+			val += btrfs_block_group_used(&block_group->item);
+	}
+	up_read(&sinfo->groups_sem);
+	return snprintf(buf, PAGE_SIZE, "%llu\n", val);
+}
+
+static struct attribute *raid_attributes[] = {
+	BTRFS_RAID_ATTR_PTR(total_bytes),
+	BTRFS_RAID_ATTR_PTR(used_bytes),
+	NULL
+};
+
+static void release_raid_kobj(struct kobject *kobj)
+{
+	kobject_put(kobj->parent);
+}
+
+struct kobj_type btrfs_raid_ktype = {
+	.sysfs_ops = &kobj_sysfs_ops,
+	.release = release_raid_kobj,
+	.default_attrs = raid_attributes,
+};
+
+#define SPACE_INFO_ATTR(field)						\
+static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,	\
+					     struct kobj_attribute *a,	\
+					     char *buf)			\
+{									\
+	struct btrfs_space_info *sinfo = to_space_info(kobj);		\
+	return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);	\
+}									\
+BTRFS_ATTR(field, 0444, btrfs_space_info_show_##field)
+
+static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
+						       struct kobj_attribute *a,
+						       char *buf)
+{
+	struct btrfs_space_info *sinfo = to_space_info(kobj);
+	s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
+	return snprintf(buf, PAGE_SIZE, "%lld\n", val);
+}
+
+SPACE_INFO_ATTR(flags);
+SPACE_INFO_ATTR(total_bytes);
+SPACE_INFO_ATTR(bytes_used);
+SPACE_INFO_ATTR(bytes_pinned);
+SPACE_INFO_ATTR(bytes_reserved);
+SPACE_INFO_ATTR(bytes_may_use);
+SPACE_INFO_ATTR(disk_used);
+SPACE_INFO_ATTR(disk_total);
+BTRFS_ATTR(total_bytes_pinned, 0444, btrfs_space_info_show_total_bytes_pinned);
+
+static struct attribute *space_info_attrs[] = {
+	BTRFS_ATTR_PTR(flags),
+	BTRFS_ATTR_PTR(total_bytes),
+	BTRFS_ATTR_PTR(bytes_used),
+	BTRFS_ATTR_PTR(bytes_pinned),
+	BTRFS_ATTR_PTR(bytes_reserved),
+	BTRFS_ATTR_PTR(bytes_may_use),
+	BTRFS_ATTR_PTR(disk_used),
+	BTRFS_ATTR_PTR(disk_total),
+	BTRFS_ATTR_PTR(total_bytes_pinned),
+	NULL,
+};
+
+static void space_info_release(struct kobject *kobj)
+{
+	struct btrfs_space_info *sinfo = to_space_info(kobj);
+	percpu_counter_destroy(&sinfo->total_bytes_pinned);
+	kfree(sinfo);
+}
+
+struct kobj_type space_info_ktype = {
+	.sysfs_ops = &kobj_sysfs_ops,
+	.release = space_info_release,
+	.default_attrs = space_info_attrs,
+};
+
+static const struct attribute *allocation_attrs[] = {
+	BTRFS_ATTR_PTR(global_rsv_reserved),
+	BTRFS_ATTR_PTR(global_rsv_size),
+	NULL,
+};
+
 static void btrfs_release_super_kobj(struct kobject *kobj)
 {
 	struct btrfs_fs_info *fs_info = to_fs_info(kobj);
@@ -239,6 +373,9 @@ static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 
 void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
 {
+	sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
+	kobject_del(fs_info->space_info_kobj);
+	kobject_put(fs_info->space_info_kobj);
 	kobject_del(&fs_info->super_kobj);
 	kobject_put(&fs_info->super_kobj);
 	wait_for_completion(&fs_info->kobj_unregister);
@@ -391,6 +528,17 @@ int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
 	if (error)
 		goto failure;
 
+	fs_info->space_info_kobj = kobject_create_and_add("allocation",
+						  &fs_info->super_kobj);
+	if (!fs_info->space_info_kobj) {
+		error = -ENOMEM;
+		goto failure;
+	}
+
+	error = sysfs_create_files(fs_info->space_info_kobj, allocation_attrs);
+	if (error)
+		goto failure;
+
 	return 0;
 failure:
 	btrfs_sysfs_remove_one(fs_info);