nilfs2: add /sys/fs/nilfs2/<device>/mounted_snapshots/<snapshot> group
This patch adds creation of <snapshot> group for every mounted
snapshot in /sys/fs/nilfs2/<device>/mounted_snapshots group.
The group contains details about mounted snapshot:
(1) inodes_count - show number of inodes for snapshot.
(2) blocks_count - show number of blocks for snapshot.
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>
diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index fc0c961..0f6148c 100644
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -112,6 +112,124 @@
}
/************************************************************************
+ * NILFS snapshot attrs *
+ ************************************************************************/
+
+static ssize_t
+nilfs_snapshot_inodes_count_show(struct nilfs_snapshot_attr *attr,
+ struct nilfs_root *root, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%llu\n",
+ (unsigned long long)atomic64_read(&root->inodes_count));
+}
+
+static ssize_t
+nilfs_snapshot_blocks_count_show(struct nilfs_snapshot_attr *attr,
+ struct nilfs_root *root, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%llu\n",
+ (unsigned long long)atomic64_read(&root->blocks_count));
+}
+
+static const char snapshot_readme_str[] =
+ "The group contains details about mounted snapshot.\n\n"
+ "(1) inodes_count\n\tshow number of inodes for snapshot.\n\n"
+ "(2) blocks_count\n\tshow number of blocks for snapshot.\n\n";
+
+static ssize_t
+nilfs_snapshot_README_show(struct nilfs_snapshot_attr *attr,
+ struct nilfs_root *root, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, snapshot_readme_str);
+}
+
+NILFS_SNAPSHOT_RO_ATTR(inodes_count);
+NILFS_SNAPSHOT_RO_ATTR(blocks_count);
+NILFS_SNAPSHOT_RO_ATTR(README);
+
+static struct attribute *nilfs_snapshot_attrs[] = {
+ NILFS_SNAPSHOT_ATTR_LIST(inodes_count),
+ NILFS_SNAPSHOT_ATTR_LIST(blocks_count),
+ NILFS_SNAPSHOT_ATTR_LIST(README),
+ NULL,
+};
+
+static ssize_t nilfs_snapshot_attr_show(struct kobject *kobj,
+ struct attribute *attr, char *buf)
+{
+ struct nilfs_root *root =
+ container_of(kobj, struct nilfs_root, snapshot_kobj);
+ struct nilfs_snapshot_attr *a =
+ container_of(attr, struct nilfs_snapshot_attr, attr);
+
+ return a->show ? a->show(a, root, buf) : 0;
+}
+
+static ssize_t nilfs_snapshot_attr_store(struct kobject *kobj,
+ struct attribute *attr,
+ const char *buf, size_t len)
+{
+ struct nilfs_root *root =
+ container_of(kobj, struct nilfs_root, snapshot_kobj);
+ struct nilfs_snapshot_attr *a =
+ container_of(attr, struct nilfs_snapshot_attr, attr);
+
+ return a->store ? a->store(a, root, buf, len) : 0;
+}
+
+static void nilfs_snapshot_attr_release(struct kobject *kobj)
+{
+ struct nilfs_root *root = container_of(kobj, struct nilfs_root,
+ snapshot_kobj);
+ complete(&root->snapshot_kobj_unregister);
+}
+
+static const struct sysfs_ops nilfs_snapshot_attr_ops = {
+ .show = nilfs_snapshot_attr_show,
+ .store = nilfs_snapshot_attr_store,
+};
+
+static struct kobj_type nilfs_snapshot_ktype = {
+ .default_attrs = nilfs_snapshot_attrs,
+ .sysfs_ops = &nilfs_snapshot_attr_ops,
+ .release = nilfs_snapshot_attr_release,
+};
+
+int nilfs_sysfs_create_snapshot_group(struct nilfs_root *root)
+{
+ struct the_nilfs *nilfs;
+ struct kobject *parent;
+ int err;
+
+ nilfs = root->nilfs;
+ parent = &nilfs->ns_dev_subgroups->sg_mounted_snapshots_kobj;
+ root->snapshot_kobj.kset = nilfs_kset;
+ init_completion(&root->snapshot_kobj_unregister);
+
+ if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
+ err = kobject_init_and_add(&root->snapshot_kobj,
+ &nilfs_snapshot_ktype,
+ &nilfs->ns_dev_kobj,
+ "current_checkpoint");
+ } else {
+ err = kobject_init_and_add(&root->snapshot_kobj,
+ &nilfs_snapshot_ktype,
+ parent,
+ "%llu", root->cno);
+ }
+
+ if (err)
+ return err;
+
+ return 0;
+}
+
+void nilfs_sysfs_delete_snapshot_group(struct nilfs_root *root)
+{
+ kobject_del(&root->snapshot_kobj);
+}
+
+/************************************************************************
* NILFS mounted snapshots attrs *
************************************************************************/