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/Documentation/ABI/testing/sysfs-fs-nilfs2 b/Documentation/ABI/testing/sysfs-fs-nilfs2
index 29dbc8f8bcbdc40f474a3ceece56c109a5f0bf0e..304ba84a973a75f3253ece300a4dbc7850aee8fa 100644 (file)
--- a/Documentation/ABI/testing/sysfs-fs-nilfs2
+++ b/Documentation/ABI/testing/sysfs-fs-nilfs2
@@ -248,3 +248,22 @@ Contact:   "Vyacheslav Dubeyko" <slava@dubeyko.com>
 Description:
                Describe content of /sys/fs/nilfs2/<device>/mounted_snapshots
                group.
+
+What:          /sys/fs/nilfs2/<device>/mounted_snapshots/<id>/inodes_count
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show number of inodes for snapshot.
+
+What:          /sys/fs/nilfs2/<device>/mounted_snapshots/<id>/blocks_count
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show number of blocks for snapshot.
+
+What:          /sys/fs/nilfs2/<device>/mounted_snapshots/<id>/README
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Describe attributes of /sys/fs/nilfs2/<device>/mounted_snapshots/<id>
+               group.

diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index fc0c961d486a15f357f740fbc60304a5d9e3988e..0f6148c8121a70f780e4dbe3c2a797f6ce01ca79 100644 (file)
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -111,6 +111,124 @@ void nilfs_sysfs_delete_##name##_group(struct the_nilfs *nilfs) \
        kobject_del(&nilfs->ns_##parent_name##_subgroups->sg_##name##_kobj); \
 }
 
+/************************************************************************
+ *                        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                     *
  ************************************************************************/

diff --git a/fs/nilfs2/sysfs.h b/fs/nilfs2/sysfs.h
index 4e84e230e9dd185e245bfd8b66f565bf90261939..677e3a1a83708d26e8fadc5a9f7eb6992ef74d59 100644 (file)
--- a/fs/nilfs2/sysfs.h
+++ b/fs/nilfs2/sysfs.h
@@ -86,6 +86,17 @@ NILFS_DEV_ATTR_STRUCT(checkpoints);
 NILFS_DEV_ATTR_STRUCT(superblock);
 NILFS_DEV_ATTR_STRUCT(segctor);
 
+#define NILFS_CP_ATTR_STRUCT(name) \
+struct nilfs_##name##_attr { \
+       struct attribute attr; \
+       ssize_t (*show)(struct nilfs_##name##_attr *, struct nilfs_root *, \
+                       char *); \
+       ssize_t (*store)(struct nilfs_##name##_attr *, struct nilfs_root *, \
+                        const char *, size_t); \
+};
+
+NILFS_CP_ATTR_STRUCT(snapshot);
+
 #define NILFS_ATTR(type, name, mode, show, store) \
        static struct nilfs_##type##_attr nilfs_##type##_attr_##name = \
                __ATTR(name, mode, show, store)
@@ -126,6 +137,13 @@ NILFS_DEV_ATTR_STRUCT(segctor);
 #define NILFS_CHECKPOINTS_RW_ATTR(name) \
        NILFS_RW_ATTR(checkpoints, name)
 
+#define NILFS_SNAPSHOT_INFO_ATTR(name) \
+       NILFS_INFO_ATTR(snapshot, name)
+#define NILFS_SNAPSHOT_RO_ATTR(name) \
+       NILFS_RO_ATTR(snapshot, name)
+#define NILFS_SNAPSHOT_RW_ATTR(name) \
+       NILFS_RW_ATTR(snapshot, name)
+
 #define NILFS_SUPERBLOCK_RO_ATTR(name) \
        NILFS_RO_ATTR(superblock, name)
 #define NILFS_SUPERBLOCK_RW_ATTR(name) \
@@ -148,6 +166,8 @@ NILFS_DEV_ATTR_STRUCT(segctor);
        (&nilfs_mounted_snapshots_attr_##name.attr)
 #define NILFS_CHECKPOINTS_ATTR_LIST(name) \
        (&nilfs_checkpoints_attr_##name.attr)
+#define NILFS_SNAPSHOT_ATTR_LIST(name) \
+       (&nilfs_snapshot_attr_##name.attr)
 #define NILFS_SUPERBLOCK_ATTR_LIST(name) \
        (&nilfs_superblock_attr_##name.attr)
 #define NILFS_SEGCTOR_ATTR_LIST(name) \

diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index 7fe822307f9862462bd0ee4193fc2f75930c515d..d01ead1bea9a738a5268908fe321eed19af3cc07 100644 (file)
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -243,6 +243,8 @@ THE_NILFS_FNS(SB_DIRTY, sb_dirty)
  * @ifile: inode file
  * @inodes_count: number of inodes
  * @blocks_count: number of blocks
+ * @snapshot_kobj: /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot>
+ * @snapshot_kobj_unregister: completion state for kernel object
  */
 struct nilfs_root {
        __u64 cno;
@@ -254,6 +256,10 @@ struct nilfs_root {
 
        atomic64_t inodes_count;
        atomic64_t blocks_count;
+
+       /* /sys/fs/<nilfs>/<device>/mounted_snapshots/<snapshot> */
+       struct kobject snapshot_kobj;
+       struct completion snapshot_kobj_unregister;
 };
 
 /* Special checkpoint number */