[PATCH v2 6/9] nilfs2: add /sys/fs/nilfs/<device>/checkpoints group

[Vyacheslav Dubeyko]

From: Vyacheslav Dubeyko <Vyacheslav.Dubeyko-***@public.gmane.org>
Subject: [PATCH v2 6/9] nilfs2: add /sys/fs/nilfs/<device>/checkpoints group

This patch adds creation of /sys/fs/nilfs/<device>/checkpoints
group.

The checkpoints group contains attributes that describe
details about volume's checkpoints:
(1) checkpoints_number - show number of checkpoints on volume.
(2) snapshots_number - show number of snapshots on volume.
(3) last_seg_checkpoint - show checkpoint number of the latest segment.
(4) next_checkpoint - show next checkpoint number.

Signed-off-by: Vyacheslav Dubeyko <Vyacheslav.Dubeyko-***@public.gmane.org>
CC: Vyacheslav Dubeyko <slava-***@public.gmane.org>
CC: Ryusuke Konishi <konishi.ryusuke-***@public.gmane.org>
CC: Michael L. Semon <mlsemon35-***@public.gmane.org>
---
fs/nilfs2/sysfs.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
fs/nilfs2/sysfs.h | 14 ++++++
2 files changed, 136 insertions(+), 1 deletion(-)

diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index 1d7ae39..dcc751b 100644
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -122,6 +122,119 @@ void nilfs_sysfs_delete_##name##_group(struct the_nilfs *nilfs) \
}

/************************************************************************
+ * NILFS checkpoints attrs *
+ ************************************************************************/
+
+static ssize_t
+nilfs_checkpoints_checkpoints_number_show(struct nilfs_checkpoints_attr *attr,
+ struct the_nilfs *nilfs,
+ char *buf)
+{
+ __u64 ncheckpoints;
+ struct nilfs_cpstat cpstat;
+ int err;
+
+ down_read(&nilfs->ns_segctor_sem);
+ err = nilfs_cpfile_get_stat(nilfs->ns_cpfile, &cpstat);
+ up_read(&nilfs->ns_segctor_sem);
+ if (err < 0) {
+ printk(KERN_ERR "NILFS: unable to get checkpoint stat: err=%d\n",
+ err);
+ return err;
+ }
+
+ ncheckpoints = cpstat.cs_ncps;
+
+ return snprintf(buf, PAGE_SIZE, "%llu\n", ncheckpoints);
+}
+
+static ssize_t
+nilfs_checkpoints_snapshots_number_show(struct nilfs_checkpoints_attr *attr,
+ struct the_nilfs *nilfs,
+ char *buf)
+{
+ __u64 nsnapshots;
+ struct nilfs_cpstat cpstat;
+ int err;
+
+ down_read(&nilfs->ns_segctor_sem);
+ err = nilfs_cpfile_get_stat(nilfs->ns_cpfile, &cpstat);
+ up_read(&nilfs->ns_segctor_sem);
+ if (err < 0) {
+ printk(KERN_ERR "NILFS: unable to get checkpoint stat: err=%d\n",
+ err);
+ return err;
+ }
+
+ nsnapshots = cpstat.cs_nsss;
+
+ return snprintf(buf, PAGE_SIZE, "%llu\n", nsnapshots);
+}
+
+static ssize_t
+nilfs_checkpoints_last_seg_checkpoint_show(struct nilfs_checkpoints_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_checkpoints_next_checkpoint_show(struct nilfs_checkpoints_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 const char checkpoints_readme_str[] =
+ "The checkpoints group contains attributes that describe\n"
+ "details about volume's checkpoints.\n\n"
+ "(1) checkpoints_number\n\tshow number of checkpoints on volume.\n\n"
+ "(2) snapshots_number\n\tshow number of snapshots on volume.\n\n"
+ "(3) last_seg_checkpoint\n"
+ "\tshow checkpoint number of the latest segment.\n\n"
+ "(4) next_checkpoint\n\tshow next checkpoint number.\n\n";
+
+static ssize_t
+nilfs_checkpoints_README_show(struct nilfs_checkpoints_attr *attr,
+ struct the_nilfs *nilfs, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, checkpoints_readme_str);
+}
+
+NILFS_CHECKPOINTS_RO_ATTR(checkpoints_number);
+NILFS_CHECKPOINTS_RO_ATTR(snapshots_number);
+NILFS_CHECKPOINTS_RO_ATTR(last_seg_checkpoint);
+NILFS_CHECKPOINTS_RO_ATTR(next_checkpoint);
+NILFS_CHECKPOINTS_RO_ATTR(README);
+
+static struct attribute *nilfs_checkpoints_attrs[] = {
+ NILFS_CHECKPOINTS_ATTR_LIST(checkpoints_number),
+ NILFS_CHECKPOINTS_ATTR_LIST(snapshots_number),
+ NILFS_CHECKPOINTS_ATTR_LIST(last_seg_checkpoint),
+ NILFS_CHECKPOINTS_ATTR_LIST(next_checkpoint),
+ NILFS_CHECKPOINTS_ATTR_LIST(README),
+ NULL,
+};
+
+NILFS_DEV_INT_GROUP_OPS(checkpoints, dev);
+NILFS_DEV_INT_GROUP_TYPE(checkpoints, dev);
+NILFS_DEV_INT_GROUP_FNS(checkpoints, dev);
+
+/************************************************************************
* NILFS segments attrs *
************************************************************************/

@@ -715,10 +828,14 @@ int nilfs_sysfs_create_device_group(struct super_block *sb)
if (err)
goto free_dev_subgroups;

- err = nilfs_sysfs_create_segments_group(nilfs);
+ err = nilfs_sysfs_create_checkpoints_group(nilfs);
if (err)
goto cleanup_dev_kobject;

+ err = nilfs_sysfs_create_segments_group(nilfs);
+ if (err)
+ goto delete_checkpoints_group;
+
err = nilfs_sysfs_create_superblock_group(nilfs);
if (err)
goto delete_segments_group;
@@ -735,6 +852,9 @@ delete_superblock_group:
delete_segments_group:
nilfs_sysfs_delete_segments_group(nilfs);

+delete_checkpoints_group:
+ nilfs_sysfs_delete_checkpoints_group(nilfs);
+
cleanup_dev_kobject:
kobject_del(&nilfs->ns_dev_kobj);

@@ -747,6 +867,7 @@ failed_create_device_group:

void nilfs_sysfs_delete_device_group(struct the_nilfs *nilfs)
{
+ nilfs_sysfs_delete_checkpoints_group(nilfs);
nilfs_sysfs_delete_segments_group(nilfs);
nilfs_sysfs_delete_superblock_group(nilfs);
nilfs_sysfs_delete_segctor_group(nilfs);
diff --git a/fs/nilfs2/sysfs.h b/fs/nilfs2/sysfs.h
index 66dae66..2ffaa69 100644
--- a/fs/nilfs2/sysfs.h
+++ b/fs/nilfs2/sysfs.h
@@ -28,6 +28,8 @@
* @sg_superblock_kobj_unregister: completion state
* @sg_segctor_kobj: /sys/fs/nilfs/<device>/segctor
* @sg_segctor_kobj_unregister: completion state
+ * @sg_checkpoints_kobj: /sys/fs/nilfs/<device>/checkpoints
+ * @sg_checkpoints_kobj_unregister: completion state
* @sg_segments_kobj: /sys/fs/nilfs/<device>/segments
* @sg_segments_kobj_unregister: completion state
*/
@@ -40,6 +42,10 @@ struct nilfs_sysfs_dev_subgroups {
struct kobject sg_segctor_kobj;
struct completion sg_segctor_kobj_unregister;

+ /* /sys/fs/nilfs/<device>/checkpoints */
+ struct kobject sg_checkpoints_kobj;
+ struct completion sg_checkpoints_kobj_unregister;
+
/* /sys/fs/nilfs/<device>/segments */
struct kobject sg_segments_kobj;
struct completion sg_segments_kobj_unregister;
@@ -67,6 +73,7 @@ struct nilfs_##name##_attr { \

NILFS_DEV_ATTR_STRUCT(dev);
NILFS_DEV_ATTR_STRUCT(segments);
+NILFS_DEV_ATTR_STRUCT(checkpoints);
NILFS_DEV_ATTR_STRUCT(superblock);
NILFS_DEV_ATTR_STRUCT(segctor);

@@ -102,6 +109,11 @@ NILFS_DEV_ATTR_STRUCT(segctor);
#define NILFS_SEGMENTS_RW_ATTR(name) \
NILFS_RW_ATTR(segs_info, name)

+#define NILFS_CHECKPOINTS_RO_ATTR(name) \
+ NILFS_RO_ATTR(checkpoints, name)
+#define NILFS_CHECKPOINTS_RW_ATTR(name) \
+ NILFS_RW_ATTR(checkpoints, name)
+
#define NILFS_SUPERBLOCK_RO_ATTR(name) \
NILFS_RO_ATTR(superblock, name)
#define NILFS_SUPERBLOCK_RW_ATTR(name) \
@@ -120,6 +132,8 @@ NILFS_DEV_ATTR_STRUCT(segctor);
(&nilfs_dev_attr_##name.attr)
#define NILFS_SEGMENTS_ATTR_LIST(name) \
(&nilfs_segments_attr_##name.attr)
+#define NILFS_CHECKPOINTS_ATTR_LIST(name) \
+ (&nilfs_checkpoints_attr_##name.attr)
#define NILFS_SUPERBLOCK_ATTR_LIST(name) \
(&nilfs_superblock_attr_##name.attr)
#define NILFS_SEGCTOR_ATTR_LIST(name) \