Description:
                Describe attributes of /sys/fs/nilfs2/<device>/superblock
                group.
+
+What:          /sys/fs/nilfs2/<device>/segctor/last_pseg_block
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show start block number of the latest segment.
+
+What:          /sys/fs/nilfs2/<device>/segctor/last_seg_sequence
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show sequence value of the latest segment.
+
+What:          /sys/fs/nilfs2/<device>/segctor/last_seg_checkpoint
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show checkpoint number of the latest segment.
+
+What:          /sys/fs/nilfs2/<device>/segctor/current_seg_sequence
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show segment sequence counter.
+
+What:          /sys/fs/nilfs2/<device>/segctor/current_last_full_seg
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show index number of the latest full segment.
+
+What:          /sys/fs/nilfs2/<device>/segctor/next_full_seg
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show index number of the full segment index
+               to be used next.
+
+What:          /sys/fs/nilfs2/<device>/segctor/next_pseg_offset
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show offset of next partial segment in the current
+               full segment.
+
+What:          /sys/fs/nilfs2/<device>/segctor/next_checkpoint
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show next checkpoint number.
+
+What:          /sys/fs/nilfs2/<device>/segctor/last_seg_write_time
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show write time of the last segment in
+               human-readable format.
+
+What:          /sys/fs/nilfs2/<device>/segctor/last_seg_write_time_secs
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show write time of the last segment in seconds.
+
+What:          /sys/fs/nilfs2/<device>/segctor/last_nongc_write_time
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show write time of the last segment not for cleaner
+               operation in human-readable format.
+
+What:          /sys/fs/nilfs2/<device>/segctor/last_nongc_write_time_secs
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show write time of the last segment not for cleaner
+               operation in seconds.
+
+What:          /sys/fs/nilfs2/<device>/segctor/dirty_data_blocks_count
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show number of dirty data blocks.
+
+What:          /sys/fs/nilfs2/<device>/segctor/README
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Describe attributes of /sys/fs/nilfs2/<device>/segctor
+               group.
 
        kobject_del(&nilfs->ns_##parent_name##_subgroups->sg_##name##_kobj); \
 }
 
+/************************************************************************
+ *                        NILFS segctor attrs                           *
+ ************************************************************************/
+
+static ssize_t
+nilfs_segctor_last_pseg_block_show(struct nilfs_segctor_attr *attr,
+                                   struct the_nilfs *nilfs,
+                                   char *buf)
+{
+       sector_t last_pseg;
+
+       spin_lock(&nilfs->ns_last_segment_lock);
+       last_pseg = nilfs->ns_last_pseg;
+       spin_unlock(&nilfs->ns_last_segment_lock);
+
+       return snprintf(buf, PAGE_SIZE, "%llu\n",
+                       (unsigned long long)last_pseg);
+}
+
+static ssize_t
+nilfs_segctor_last_seg_sequence_show(struct nilfs_segctor_attr *attr,
+                                       struct the_nilfs *nilfs,
+                                       char *buf)
+{
+       u64 last_seq;
+
+       spin_lock(&nilfs->ns_last_segment_lock);
+       last_seq = nilfs->ns_last_seq;
+       spin_unlock(&nilfs->ns_last_segment_lock);
+
+       return snprintf(buf, PAGE_SIZE, "%llu\n", last_seq);
+}
+
+static ssize_t
+nilfs_segctor_last_seg_checkpoint_show(struct nilfs_segctor_attr *attr,
+                                       struct the_nilfs *nilfs,
+                                       char *buf)
+{
+       __u64 last_cno;
+
+       spin_lock(&nilfs->ns_last_segment_lock);
+       last_cno = nilfs->ns_last_cno;
+       spin_unlock(&nilfs->ns_last_segment_lock);
+
+       return snprintf(buf, PAGE_SIZE, "%llu\n", last_cno);
+}
+
+static ssize_t
+nilfs_segctor_current_seg_sequence_show(struct nilfs_segctor_attr *attr,
+                                       struct the_nilfs *nilfs,
+                                       char *buf)
+{
+       u64 seg_seq;
+
+       down_read(&nilfs->ns_sem);
+       seg_seq = nilfs->ns_seg_seq;
+       up_read(&nilfs->ns_sem);
+
+       return snprintf(buf, PAGE_SIZE, "%llu\n", seg_seq);
+}
+
+static ssize_t
+nilfs_segctor_current_last_full_seg_show(struct nilfs_segctor_attr *attr,
+                                        struct the_nilfs *nilfs,
+                                        char *buf)
+{
+       __u64 segnum;
+
+       down_read(&nilfs->ns_sem);
+       segnum = nilfs->ns_segnum;
+       up_read(&nilfs->ns_sem);
+
+       return snprintf(buf, PAGE_SIZE, "%llu\n", segnum);
+}
+
+static ssize_t
+nilfs_segctor_next_full_seg_show(struct nilfs_segctor_attr *attr,
+                                struct the_nilfs *nilfs,
+                                char *buf)
+{
+       __u64 nextnum;
+
+       down_read(&nilfs->ns_sem);
+       nextnum = nilfs->ns_nextnum;
+       up_read(&nilfs->ns_sem);
+
+       return snprintf(buf, PAGE_SIZE, "%llu\n", nextnum);
+}
+
+static ssize_t
+nilfs_segctor_next_pseg_offset_show(struct nilfs_segctor_attr *attr,
+                                       struct the_nilfs *nilfs,
+                                       char *buf)
+{
+       unsigned long pseg_offset;
+
+       down_read(&nilfs->ns_sem);
+       pseg_offset = nilfs->ns_pseg_offset;
+       up_read(&nilfs->ns_sem);
+
+       return snprintf(buf, PAGE_SIZE, "%lu\n", pseg_offset);
+}
+
+static ssize_t
+nilfs_segctor_next_checkpoint_show(struct nilfs_segctor_attr *attr,
+                                       struct the_nilfs *nilfs,
+                                       char *buf)
+{
+       __u64 cno;
+
+       down_read(&nilfs->ns_sem);
+       cno = nilfs->ns_cno;
+       up_read(&nilfs->ns_sem);
+
+       return snprintf(buf, PAGE_SIZE, "%llu\n", cno);
+}
+
+static ssize_t
+nilfs_segctor_last_seg_write_time_show(struct nilfs_segctor_attr *attr,
+                                       struct the_nilfs *nilfs,
+                                       char *buf)
+{
+       time_t ctime;
+
+       down_read(&nilfs->ns_sem);
+       ctime = nilfs->ns_ctime;
+       up_read(&nilfs->ns_sem);
+
+       return NILFS_SHOW_TIME(ctime, buf);
+}
+
+static ssize_t
+nilfs_segctor_last_seg_write_time_secs_show(struct nilfs_segctor_attr *attr,
+                                           struct the_nilfs *nilfs,
+                                           char *buf)
+{
+       time_t ctime;
+
+       down_read(&nilfs->ns_sem);
+       ctime = nilfs->ns_ctime;
+       up_read(&nilfs->ns_sem);
+
+       return snprintf(buf, PAGE_SIZE, "%llu\n", (unsigned long long)ctime);
+}
+
+static ssize_t
+nilfs_segctor_last_nongc_write_time_show(struct nilfs_segctor_attr *attr,
+                                        struct the_nilfs *nilfs,
+                                        char *buf)
+{
+       time_t nongc_ctime;
+
+       down_read(&nilfs->ns_sem);
+       nongc_ctime = nilfs->ns_nongc_ctime;
+       up_read(&nilfs->ns_sem);
+
+       return NILFS_SHOW_TIME(nongc_ctime, buf);
+}
+
+static ssize_t
+nilfs_segctor_last_nongc_write_time_secs_show(struct nilfs_segctor_attr *attr,
+                                               struct the_nilfs *nilfs,
+                                               char *buf)
+{
+       time_t nongc_ctime;
+
+       down_read(&nilfs->ns_sem);
+       nongc_ctime = nilfs->ns_nongc_ctime;
+       up_read(&nilfs->ns_sem);
+
+       return snprintf(buf, PAGE_SIZE, "%llu\n",
+                       (unsigned long long)nongc_ctime);
+}
+
+static ssize_t
+nilfs_segctor_dirty_data_blocks_count_show(struct nilfs_segctor_attr *attr,
+                                           struct the_nilfs *nilfs,
+                                           char *buf)
+{
+       u32 ndirtyblks;
+
+       down_read(&nilfs->ns_sem);
+       ndirtyblks = atomic_read(&nilfs->ns_ndirtyblks);
+       up_read(&nilfs->ns_sem);
+
+       return snprintf(buf, PAGE_SIZE, "%u\n", ndirtyblks);
+}
+
+static const char segctor_readme_str[] =
+       "The segctor group contains attributes that describe\n"
+       "segctor thread activity details.\n\n"
+       "(1) last_pseg_block\n"
+       "\tshow start block number of the latest segment.\n\n"
+       "(2) last_seg_sequence\n"
+       "\tshow sequence value of the latest segment.\n\n"
+       "(3) last_seg_checkpoint\n"
+       "\tshow checkpoint number of the latest segment.\n\n"
+       "(4) current_seg_sequence\n\tshow segment sequence counter.\n\n"
+       "(5) current_last_full_seg\n"
+       "\tshow index number of the latest full segment.\n\n"
+       "(6) next_full_seg\n"
+       "\tshow index number of the full segment index to be used next.\n\n"
+       "(7) next_pseg_offset\n"
+       "\tshow offset of next partial segment in the current full segment.\n\n"
+       "(8) next_checkpoint\n\tshow next checkpoint number.\n\n"
+       "(9) last_seg_write_time\n"
+       "\tshow write time of the last segment in human-readable format.\n\n"
+       "(10) last_seg_write_time_secs\n"
+       "\tshow write time of the last segment in seconds.\n\n"
+       "(11) last_nongc_write_time\n"
+       "\tshow write time of the last segment not for cleaner operation "
+       "in human-readable format.\n\n"
+       "(12) last_nongc_write_time_secs\n"
+       "\tshow write time of the last segment not for cleaner operation "
+       "in seconds.\n\n"
+       "(13) dirty_data_blocks_count\n"
+       "\tshow number of dirty data blocks.\n\n";
+
+static ssize_t
+nilfs_segctor_README_show(struct nilfs_segctor_attr *attr,
+                         struct the_nilfs *nilfs, char *buf)
+{
+       return snprintf(buf, PAGE_SIZE, segctor_readme_str);
+}
+
+NILFS_SEGCTOR_RO_ATTR(last_pseg_block);
+NILFS_SEGCTOR_RO_ATTR(last_seg_sequence);
+NILFS_SEGCTOR_RO_ATTR(last_seg_checkpoint);
+NILFS_SEGCTOR_RO_ATTR(current_seg_sequence);
+NILFS_SEGCTOR_RO_ATTR(current_last_full_seg);
+NILFS_SEGCTOR_RO_ATTR(next_full_seg);
+NILFS_SEGCTOR_RO_ATTR(next_pseg_offset);
+NILFS_SEGCTOR_RO_ATTR(next_checkpoint);
+NILFS_SEGCTOR_RO_ATTR(last_seg_write_time);
+NILFS_SEGCTOR_RO_ATTR(last_seg_write_time_secs);
+NILFS_SEGCTOR_RO_ATTR(last_nongc_write_time);
+NILFS_SEGCTOR_RO_ATTR(last_nongc_write_time_secs);
+NILFS_SEGCTOR_RO_ATTR(dirty_data_blocks_count);
+NILFS_SEGCTOR_RO_ATTR(README);
+
+static struct attribute *nilfs_segctor_attrs[] = {
+       NILFS_SEGCTOR_ATTR_LIST(last_pseg_block),
+       NILFS_SEGCTOR_ATTR_LIST(last_seg_sequence),
+       NILFS_SEGCTOR_ATTR_LIST(last_seg_checkpoint),
+       NILFS_SEGCTOR_ATTR_LIST(current_seg_sequence),
+       NILFS_SEGCTOR_ATTR_LIST(current_last_full_seg),
+       NILFS_SEGCTOR_ATTR_LIST(next_full_seg),
+       NILFS_SEGCTOR_ATTR_LIST(next_pseg_offset),
+       NILFS_SEGCTOR_ATTR_LIST(next_checkpoint),
+       NILFS_SEGCTOR_ATTR_LIST(last_seg_write_time),
+       NILFS_SEGCTOR_ATTR_LIST(last_seg_write_time_secs),
+       NILFS_SEGCTOR_ATTR_LIST(last_nongc_write_time),
+       NILFS_SEGCTOR_ATTR_LIST(last_nongc_write_time_secs),
+       NILFS_SEGCTOR_ATTR_LIST(dirty_data_blocks_count),
+       NILFS_SEGCTOR_ATTR_LIST(README),
+       NULL,
+};
+
+NILFS_DEV_INT_GROUP_OPS(segctor, dev);
+NILFS_DEV_INT_GROUP_TYPE(segctor, dev);
+NILFS_DEV_INT_GROUP_FNS(segctor, dev);
+
 /************************************************************************
  *                        NILFS superblock attrs                        *
  ************************************************************************/
        if (err)
                goto cleanup_dev_kobject;
 
+       err = nilfs_sysfs_create_segctor_group(nilfs);
+       if (err)
+               goto delete_superblock_group;
+
        return 0;
 
+delete_superblock_group:
+       nilfs_sysfs_delete_superblock_group(nilfs);
+
 cleanup_dev_kobject:
        kobject_del(&nilfs->ns_dev_kobj);
 
 void nilfs_sysfs_delete_device_group(struct the_nilfs *nilfs)
 {
        nilfs_sysfs_delete_superblock_group(nilfs);
+       nilfs_sysfs_delete_segctor_group(nilfs);
        kobject_del(&nilfs->ns_dev_kobj);
        kfree(nilfs->ns_dev_subgroups);
 }