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

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

The <device> group contains attributes that describe file
system partition's details:
(1) revision - show NILFS file system revision.
(2) blocksize - show volume block size in bytes.
(3) device_size - show volume size in bytes.
(4) free_blocks - show count of free blocks on volume.
(5) uuid - show volume's UUID.
(6) volume_name - show volume's name.

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 71b4fd3..0a521d0 100644 (file)
--- a/Documentation/ABI/testing/sysfs-fs-nilfs2
+++ b/Documentation/ABI/testing/sysfs-fs-nilfs2
@@ -12,3 +12,47 @@ Date:                April 2014
 Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
 Description:
                Describe attributes of /sys/fs/nilfs2/features group.
+
+What:          /sys/fs/nilfs2/<device>/revision
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show NILFS file system revision on volume.
+               This value informs about metadata structures'
+               revision on mounted volume.
+
+What:          /sys/fs/nilfs2/<device>/blocksize
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show volume's block size in bytes.
+
+What:          /sys/fs/nilfs2/<device>/device_size
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show volume size in bytes.
+
+What:          /sys/fs/nilfs2/<device>/free_blocks
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show count of free blocks on volume.
+
+What:          /sys/fs/nilfs2/<device>/uuid
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show volume's UUID (Universally Unique Identifier).
+
+What:          /sys/fs/nilfs2/<device>/volume_name
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Show volume's label.
+
+What:          /sys/fs/nilfs2/<device>/README
+Date:          April 2014
+Contact:       "Vyacheslav Dubeyko" <slava@dubeyko.com>
+Description:
+               Describe attributes of /sys/fs/nilfs2/<device> group.

diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index 41b8f70..780d0f5 100644 (file)
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -41,6 +41,174 @@ static struct kset *nilfs_kset;
                count; \
 })
 
+/************************************************************************
+ *                        NILFS device attrs                            *
+ ************************************************************************/
+
+static
+ssize_t nilfs_dev_revision_show(struct nilfs_dev_attr *attr,
+                               struct the_nilfs *nilfs,
+                               char *buf)
+{
+       struct nilfs_super_block **sbp = nilfs->ns_sbp;
+       u32 major = le32_to_cpu(sbp[0]->s_rev_level);
+       u16 minor = le16_to_cpu(sbp[0]->s_minor_rev_level);
+
+       return snprintf(buf, PAGE_SIZE, "%d.%d\n", major, minor);
+}
+
+static
+ssize_t nilfs_dev_blocksize_show(struct nilfs_dev_attr *attr,
+                                struct the_nilfs *nilfs,
+                                char *buf)
+{
+       return snprintf(buf, PAGE_SIZE, "%u\n", nilfs->ns_blocksize);
+}
+
+static
+ssize_t nilfs_dev_device_size_show(struct nilfs_dev_attr *attr,
+                                   struct the_nilfs *nilfs,
+                                   char *buf)
+{
+       struct nilfs_super_block **sbp = nilfs->ns_sbp;
+       u64 dev_size = le64_to_cpu(sbp[0]->s_dev_size);
+
+       return snprintf(buf, PAGE_SIZE, "%llu\n", dev_size);
+}
+
+static
+ssize_t nilfs_dev_free_blocks_show(struct nilfs_dev_attr *attr,
+                                  struct the_nilfs *nilfs,
+                                  char *buf)
+{
+       sector_t free_blocks = 0;
+
+       nilfs_count_free_blocks(nilfs, &free_blocks);
+       return snprintf(buf, PAGE_SIZE, "%llu\n",
+                       (unsigned long long)free_blocks);
+}
+
+static
+ssize_t nilfs_dev_uuid_show(struct nilfs_dev_attr *attr,
+                           struct the_nilfs *nilfs,
+                           char *buf)
+{
+       struct nilfs_super_block **sbp = nilfs->ns_sbp;
+
+       return snprintf(buf, PAGE_SIZE, "%pUb\n", sbp[0]->s_uuid);
+}
+
+static
+ssize_t nilfs_dev_volume_name_show(struct nilfs_dev_attr *attr,
+                                   struct the_nilfs *nilfs,
+                                   char *buf)
+{
+       struct nilfs_super_block **sbp = nilfs->ns_sbp;
+
+       return scnprintf(buf, sizeof(sbp[0]->s_volume_name), "%s\n",
+                        sbp[0]->s_volume_name);
+}
+
+static const char dev_readme_str[] =
+       "The <device> group contains attributes that describe file system\n"
+       "partition's details.\n\n"
+       "(1) revision\n\tshow NILFS file system revision.\n\n"
+       "(2) blocksize\n\tshow volume block size in bytes.\n\n"
+       "(3) device_size\n\tshow volume size in bytes.\n\n"
+       "(4) free_blocks\n\tshow count of free blocks on volume.\n\n"
+       "(5) uuid\n\tshow volume's UUID.\n\n"
+       "(6) volume_name\n\tshow volume's name.\n\n";
+
+static ssize_t nilfs_dev_README_show(struct nilfs_dev_attr *attr,
+                                    struct the_nilfs *nilfs,
+                                    char *buf)
+{
+       return snprintf(buf, PAGE_SIZE, dev_readme_str);
+}
+
+NILFS_DEV_RO_ATTR(revision);
+NILFS_DEV_RO_ATTR(blocksize);
+NILFS_DEV_RO_ATTR(device_size);
+NILFS_DEV_RO_ATTR(free_blocks);
+NILFS_DEV_RO_ATTR(uuid);
+NILFS_DEV_RO_ATTR(volume_name);
+NILFS_DEV_RO_ATTR(README);
+
+static struct attribute *nilfs_dev_attrs[] = {
+       NILFS_DEV_ATTR_LIST(revision),
+       NILFS_DEV_ATTR_LIST(blocksize),
+       NILFS_DEV_ATTR_LIST(device_size),
+       NILFS_DEV_ATTR_LIST(free_blocks),
+       NILFS_DEV_ATTR_LIST(uuid),
+       NILFS_DEV_ATTR_LIST(volume_name),
+       NILFS_DEV_ATTR_LIST(README),
+       NULL,
+};
+
+static ssize_t nilfs_dev_attr_show(struct kobject *kobj,
+                                   struct attribute *attr, char *buf)
+{
+       struct the_nilfs *nilfs = container_of(kobj, struct the_nilfs,
+                                               ns_dev_kobj);
+       struct nilfs_dev_attr *a = container_of(attr, struct nilfs_dev_attr,
+                                               attr);
+
+       return a->show ? a->show(a, nilfs, buf) : 0;
+}
+
+static ssize_t nilfs_dev_attr_store(struct kobject *kobj,
+                                   struct attribute *attr,
+                                   const char *buf, size_t len)
+{
+       struct the_nilfs *nilfs = container_of(kobj, struct the_nilfs,
+                                               ns_dev_kobj);
+       struct nilfs_dev_attr *a = container_of(attr, struct nilfs_dev_attr,
+                                               attr);
+
+       return a->store ? a->store(a, nilfs, buf, len) : 0;
+}
+
+static void nilfs_dev_attr_release(struct kobject *kobj)
+{
+       struct the_nilfs *nilfs = container_of(kobj, struct the_nilfs,
+                                               ns_dev_kobj);
+       complete(&nilfs->ns_dev_kobj_unregister);
+}
+
+static const struct sysfs_ops nilfs_dev_attr_ops = {
+       .show   = nilfs_dev_attr_show,
+       .store  = nilfs_dev_attr_store,
+};
+
+static struct kobj_type nilfs_dev_ktype = {
+       .default_attrs  = nilfs_dev_attrs,
+       .sysfs_ops      = &nilfs_dev_attr_ops,
+       .release        = nilfs_dev_attr_release,
+};
+
+int nilfs_sysfs_create_device_group(struct super_block *sb)
+{
+       struct the_nilfs *nilfs = sb->s_fs_info;
+       int err;
+
+       nilfs->ns_dev_kobj.kset = nilfs_kset;
+       init_completion(&nilfs->ns_dev_kobj_unregister);
+       err = kobject_init_and_add(&nilfs->ns_dev_kobj, &nilfs_dev_ktype, NULL,
+                                   "%s", sb->s_id);
+       if (err)
+               goto failed_create_device_group;
+
+       return 0;
+
+failed_create_device_group:
+       return err;
+}
+
+void nilfs_sysfs_delete_device_group(struct the_nilfs *nilfs)
+{
+       kobject_del(&nilfs->ns_dev_kobj);
+}
+
 /************************************************************************
  *                        NILFS feature attrs                           *
  ************************************************************************/

diff --git a/fs/nilfs2/sysfs.h b/fs/nilfs2/sysfs.h
index 0aed246..2353b28 100644 (file)
--- a/fs/nilfs2/sysfs.h
+++ b/fs/nilfs2/sysfs.h
@@ -35,6 +35,17 @@ struct nilfs_##name##_attr { \
 
 NILFS_COMMON_ATTR_STRUCT(feature);
 
+#define NILFS_DEV_ATTR_STRUCT(name) \
+struct nilfs_##name##_attr { \
+       struct attribute attr; \
+       ssize_t (*show)(struct nilfs_##name##_attr *, struct the_nilfs *, \
+                       char *); \
+       ssize_t (*store)(struct nilfs_##name##_attr *, struct the_nilfs *, \
+                        const char *, size_t); \
+};
+
+NILFS_DEV_ATTR_STRUCT(dev);
+
 #define NILFS_ATTR(type, name, mode, show, store) \
        static struct nilfs_##type##_attr nilfs_##type##_attr_##name = \
                __ATTR(name, mode, show, store)
@@ -55,7 +66,16 @@ NILFS_COMMON_ATTR_STRUCT(feature);
 #define NILFS_FEATURE_RW_ATTR(name) \
        NILFS_RW_ATTR(feature, name)
 
+#define NILFS_DEV_INFO_ATTR(name) \
+       NILFS_INFO_ATTR(dev, name)
+#define NILFS_DEV_RO_ATTR(name) \
+       NILFS_RO_ATTR(dev, name)
+#define NILFS_DEV_RW_ATTR(name) \
+       NILFS_RW_ATTR(dev, name)
+
 #define NILFS_FEATURE_ATTR_LIST(name) \
        (&nilfs_feature_attr_##name.attr)
+#define NILFS_DEV_ATTR_LIST(name) \
+       (&nilfs_dev_attr_##name.attr)
 
 #endif /* _NILFS_SYSFS_H */

diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index de8cc53..34bc7bd 100644 (file)
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -95,6 +95,8 @@ enum {
  * @ns_inode_size: size of on-disk inode
  * @ns_first_ino: first not-special inode number
  * @ns_crc_seed: seed value of CRC32 calculation
+ * @ns_dev_kobj: /sys/fs/<nilfs>/<device>
+ * @ns_dev_kobj_unregister: completion state
  */
 struct the_nilfs {
        unsigned long           ns_flags;
@@ -188,6 +190,10 @@ struct the_nilfs {
        int                     ns_inode_size;
        int                     ns_first_ino;
        u32                     ns_crc_seed;
+
+       /* /sys/fs/<nilfs>/<device> */
+       struct kobject ns_dev_kobj;
+       struct completion ns_dev_kobj_unregister;
 };
 
 #define THE_NILFS_FNS(bit, name)                                       \