[PATCH v2 2/9] nilfs2: add /sys/fs/nilfs/<device> group

[Vyacheslav Dubeyko]

From: Vyacheslav Dubeyko <Vyacheslav.Dubeyko-***@public.gmane.org>
Subject: [PATCH v2 2/9] nilfs2: add /sys/fs/nilfs/<device> group

This patch adds creation of /sys/fs/nilfs/<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-***@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 | 168 +++++++++++++++++++++++++++++++++++++++++++++++++
fs/nilfs2/sysfs.h | 20 ++++++
fs/nilfs2/the_nilfs.h | 6 ++
3 files changed, 194 insertions(+)

diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index 5a36902..8f28934 100644
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -52,6 +52,174 @@ static int nilfs_show_time_format = NILFS_SHOW_HUMAN_READABLE_TIME;
})

/************************************************************************
+ * 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, "%pUL\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 b3ba2e4..19ff1a1 100644
--- a/fs/nilfs2/sysfs.h
+++ b/fs/nilfs2/sysfs.h
@@ -33,6 +33,17 @@ 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)
@@ -53,7 +64,16 @@ 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..42557d0 100644
--- 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) \