nilfs2: add /sys/fs/nilfs2/<device>/segments group

This patch adds creation of /sys/fs/nilfs2/<device>/segments
group.

The segments group contains attributes that describe
details about volume's segments:
(1) segments_number - show number of segments on volume.
(2) blocks_per_segment - show number of blocks in segment.
(3) clean_segments - show count of clean segments.
(4) dirty_segments - show count of dirty segments.

Signed-off-by: Vyacheslav Dubeyko <Vyacheslav.Dubeyko@hgst.com>
Cc: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Michael L. Semon <mlsemon35@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 112 insertions, 1 deletions

diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index 61454a859e81..fe8e1411dc6a 100644
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -112,6 +112,95 @@ void nilfs_sysfs_delete_##name##_group(struct the_nilfs *nilfs) \
 }
 
 /************************************************************************
+ *                        NILFS segments attrs                          *
+ ************************************************************************/
+
+static ssize_t
+nilfs_segments_segments_number_show(struct nilfs_segments_attr *attr,
+                                     struct the_nilfs *nilfs,
+                                     char *buf)
+{
+        return snprintf(buf, PAGE_SIZE, "%lu\n", nilfs->ns_nsegments);
+}
+
+static ssize_t
+nilfs_segments_blocks_per_segment_show(struct nilfs_segments_attr *attr,
+                                        struct the_nilfs *nilfs,
+                                        char *buf)
+{
+        return snprintf(buf, PAGE_SIZE, "%lu\n", nilfs->ns_blocks_per_segment);
+}
+
+static ssize_t
+nilfs_segments_clean_segments_show(struct nilfs_segments_attr *attr,
+                                    struct the_nilfs *nilfs,
+                                    char *buf)
+{
+        unsigned long ncleansegs;
+
+        down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
+        ncleansegs = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile);
+        up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
+
+        return snprintf(buf, PAGE_SIZE, "%lu\n", ncleansegs);
+}
+
+static ssize_t
+nilfs_segments_dirty_segments_show(struct nilfs_segments_attr *attr,
+                                    struct the_nilfs *nilfs,
+                                    char *buf)
+{
+        struct nilfs_sustat sustat;
+        int err;
+
+        down_read(&nilfs->ns_segctor_sem);
+        err = nilfs_sufile_get_stat(nilfs->ns_sufile, &sustat);
+        up_read(&nilfs->ns_segctor_sem);
+        if (err < 0) {
+                printk(KERN_ERR "NILFS: unable to get segment stat: err=%d\n",
+                        err);
+                return err;
+        }
+
+        return snprintf(buf, PAGE_SIZE, "%llu\n", sustat.ss_ndirtysegs);
+}
+
+static const char segments_readme_str[] =
+        "The segments group contains attributes that describe\n"
+        "details about volume's segments.\n\n"
+        "(1) segments_number\n\tshow number of segments on volume.\n\n"
+        "(2) blocks_per_segment\n\tshow number of blocks in segment.\n\n"
+        "(3) clean_segments\n\tshow count of clean segments.\n\n"
+        "(4) dirty_segments\n\tshow count of dirty segments.\n\n";
+
+static ssize_t
+nilfs_segments_README_show(struct nilfs_segments_attr *attr,
+                            struct the_nilfs *nilfs,
+                            char *buf)
+{
+        return snprintf(buf, PAGE_SIZE, segments_readme_str);
+}
+
+NILFS_SEGMENTS_RO_ATTR(segments_number);
+NILFS_SEGMENTS_RO_ATTR(blocks_per_segment);
+NILFS_SEGMENTS_RO_ATTR(clean_segments);
+NILFS_SEGMENTS_RO_ATTR(dirty_segments);
+NILFS_SEGMENTS_RO_ATTR(README);
+
+static struct attribute *nilfs_segments_attrs[] = {
+        NILFS_SEGMENTS_ATTR_LIST(segments_number),
+        NILFS_SEGMENTS_ATTR_LIST(blocks_per_segment),
+        NILFS_SEGMENTS_ATTR_LIST(clean_segments),
+        NILFS_SEGMENTS_ATTR_LIST(dirty_segments),
+        NILFS_SEGMENTS_ATTR_LIST(README),
+        NULL,
+};
+
+NILFS_DEV_INT_GROUP_OPS(segments, dev);
+NILFS_DEV_INT_GROUP_TYPE(segments, dev);
+NILFS_DEV_INT_GROUP_FNS(segments, dev);
+
+/************************************************************************
  *                        NILFS segctor attrs                           *
  ************************************************************************/
 
@@ -664,10 +753,14 @@ int nilfs_sysfs_create_device_group(struct super_block *sb)
         if (err)
                 goto free_dev_subgroups;
 
-        err = nilfs_sysfs_create_superblock_group(nilfs);
+        err = nilfs_sysfs_create_segments_group(nilfs);
         if (err)
                 goto cleanup_dev_kobject;
 
+        err = nilfs_sysfs_create_superblock_group(nilfs);
+        if (err)
+                goto delete_segments_group;
+
         err = nilfs_sysfs_create_segctor_group(nilfs);
         if (err)
                 goto delete_superblock_group;
@@ -677,6 +770,9 @@ int nilfs_sysfs_create_device_group(struct super_block *sb)
 delete_superblock_group:
         nilfs_sysfs_delete_superblock_group(nilfs);
 
+delete_segments_group:
+        nilfs_sysfs_delete_segments_group(nilfs);
+
 cleanup_dev_kobject:
         kobject_del(&nilfs->ns_dev_kobj);
 
@@ -689,6 +785,7 @@ failed_create_device_group:
 
 void nilfs_sysfs_delete_device_group(struct the_nilfs *nilfs)
 {
+        nilfs_sysfs_delete_segments_group(nilfs);
         nilfs_sysfs_delete_superblock_group(nilfs);
         nilfs_sysfs_delete_segctor_group(nilfs);
         kobject_del(&nilfs->ns_dev_kobj);
diff --git a/fs/nilfs2/sysfs.h b/fs/nilfs2/sysfs.h
index ad4d5bcc16f5..228bdd14f945 100644
--- a/fs/nilfs2/sysfs.h
+++ b/fs/nilfs2/sysfs.h
@@ -30,6 +30,8 @@
  * @sg_superblock_kobj_unregister: completion state
  * @sg_segctor_kobj: /sys/fs/<nilfs>/<device>/segctor
  * @sg_segctor_kobj_unregister: completion state
+ * @sg_segments_kobj: /sys/fs/<nilfs>/<device>/segments
+ * @sg_segments_kobj_unregister: completion state
  */
 struct nilfs_sysfs_dev_subgroups {
         /* /sys/fs/<nilfs>/<device>/superblock */
@@ -39,6 +41,10 @@ struct nilfs_sysfs_dev_subgroups {
         /* /sys/fs/<nilfs>/<device>/segctor */
         struct kobject sg_segctor_kobj;
         struct completion sg_segctor_kobj_unregister;
+
+        /* /sys/fs/<nilfs>/<device>/segments */
+        struct kobject sg_segments_kobj;
+        struct completion sg_segments_kobj_unregister;
 };
 
 #define NILFS_COMMON_ATTR_STRUCT(name) \
@@ -62,6 +68,7 @@ struct nilfs_##name##_attr { \
 };
 
 NILFS_DEV_ATTR_STRUCT(dev);
+NILFS_DEV_ATTR_STRUCT(segments);
 NILFS_DEV_ATTR_STRUCT(superblock);
 NILFS_DEV_ATTR_STRUCT(segctor);
 
@@ -92,6 +99,11 @@ NILFS_DEV_ATTR_STRUCT(segctor);
 #define NILFS_DEV_RW_ATTR(name) \
         NILFS_RW_ATTR(dev, name)
 
+#define NILFS_SEGMENTS_RO_ATTR(name) \
+        NILFS_RO_ATTR(segments, name)
+#define NILFS_SEGMENTS_RW_ATTR(name) \
+        NILFS_RW_ATTR(segs_info, name)
+
 #define NILFS_SUPERBLOCK_RO_ATTR(name) \
         NILFS_RO_ATTR(superblock, name)
 #define NILFS_SUPERBLOCK_RW_ATTR(name) \
@@ -108,6 +120,8 @@ NILFS_DEV_ATTR_STRUCT(segctor);
         (&nilfs_feature_attr_##name.attr)
 #define NILFS_DEV_ATTR_LIST(name) \
         (&nilfs_dev_attr_##name.attr)
+#define NILFS_SEGMENTS_ATTR_LIST(name) \
+        (&nilfs_segments_attr_##name.attr)
 #define NILFS_SUPERBLOCK_ATTR_LIST(name) \
         (&nilfs_superblock_attr_##name.attr)
 #define NILFS_SEGCTOR_ATTR_LIST(name) \