To allow applications to easily check the current usage status of the
open zone resources of the mounted device, export through sysfs the
counter of write open sequential files s_wro_seq_files field of
struct zonefs_sb_info. The attribute is named nr_wro_seq_files and is
read only.
The maximum number of write open sequential files (zones) indicated by
the s_max_wro_seq_files field of struct zonefs_sb_info is also exported
as the read only attribute max_wro_seq_files.
Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
---
fs/zonefs/Makefile | 2 +-
fs/zonefs/super.c | 24 +++++++--
fs/zonefs/sysfs.c | 125 +++++++++++++++++++++++++++++++++++++++++++++
fs/zonefs/zonefs.h | 10 ++++
4 files changed, 156 insertions(+), 5 deletions(-)
create mode 100644 fs/zonefs/sysfs.c
diff --git a/fs/zonefs/Makefile b/fs/zonefs/Makefile
index 33c1a4f1132e..9fe54f5319f2 100644
--- a/fs/zonefs/Makefile
+++ b/fs/zonefs/Makefile
@@ -3,4 +3,4 @@ ccflags-y += -I$(src)
obj-$(CONFIG_ZONEFS_FS) += zonefs.o
-zonefs-y := super.o
+zonefs-y := super.o sysfs.o
diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index 02dbdec32b2f..aa359f27102e 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -1725,6 +1725,10 @@ static int zonefs_fill_super(struct super_block *sb, void *data, int silent)
if (ret)
goto cleanup;
+ ret = zonefs_sysfs_register(sb);
+ if (ret)
+ goto cleanup;
+
zonefs_info(sb, "Mounting %u zones",
blkdev_nr_zones(sb->s_bdev->bd_disk));
@@ -1770,6 +1774,8 @@ static void zonefs_kill_super(struct super_block *sb)
if (sb->s_root)
d_genocide(sb->s_root);
+
+ zonefs_sysfs_unregister(sb);
kill_block_super(sb);
kfree(sbi);
}
@@ -1817,16 +1823,26 @@ static int __init zonefs_init(void)
return ret;
ret = register_filesystem(&zonefs_type);
- if (ret) {
- zonefs_destroy_inodecache();
- return ret;
- }
+ if (ret)
+ goto destroy_inodecache;
+
+ ret = zonefs_sysfs_init();
+ if (ret)
+ goto unregister_fs;
return 0;
+
+unregister_fs:
+ unregister_filesystem(&zonefs_type);
+destroy_inodecache:
+ zonefs_destroy_inodecache();
+
+ return ret;
}
static void __exit zonefs_exit(void)
{
+ zonefs_sysfs_exit();
zonefs_destroy_inodecache();
unregister_filesystem(&zonefs_type);
}
diff --git a/fs/zonefs/sysfs.c b/fs/zonefs/sysfs.c
new file mode 100644
index 000000000000..eaeaf983ed87
--- /dev/null
+++ b/fs/zonefs/sysfs.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple file system for zoned block devices exposing zones as files.
+ *
+ * Copyright (C) 2022 Western Digital Corporation or its affiliates.
+ */
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/blkdev.h>
+
+#include "zonefs.h"
+
+struct zonefs_sysfs_attr {
+ struct attribute attr;
+ ssize_t (*show)(struct zonefs_sb_info *sbi, char *buf);
+};
+
+static inline struct zonefs_sysfs_attr *to_attr(struct attribute *attr)
+{
+ return container_of(attr, struct zonefs_sysfs_attr, attr);
+}
+
+#define ZONEFS_SYSFS_ATTR_RO(name) \
+static struct zonefs_sysfs_attr zonefs_sysfs_attr_##name = __ATTR_RO(name)
+
+#define ATTR_LIST(name) &zonefs_sysfs_attr_##name.attr
+
+static ssize_t zonefs_sysfs_attr_show(struct kobject *kobj,
+ struct attribute *attr, char *buf)
+{
+ struct zonefs_sb_info *sbi =
+ container_of(kobj, struct zonefs_sb_info, s_kobj);
+ struct zonefs_sysfs_attr *zonefs_attr =
+ container_of(attr, struct zonefs_sysfs_attr, attr);
+
+ if (!zonefs_attr->show)
+ return 0;
+
+ return zonefs_attr->show(sbi, buf);
+}
+
+static ssize_t max_wro_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
+{
+ return sysfs_emit(buf, "%u\n", sbi->s_max_wro_seq_files);
+}
+ZONEFS_SYSFS_ATTR_RO(max_wro_seq_files);
+
+static ssize_t nr_wro_seq_files_show(struct zonefs_sb_info *sbi, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", atomic_read(&sbi->s_wro_seq_files));
+}
+ZONEFS_SYSFS_ATTR_RO(nr_wro_seq_files);
+
+static struct attribute *zonefs_sysfs_attrs[] = {
+ ATTR_LIST(max_wro_seq_files),
+ ATTR_LIST(nr_wro_seq_files),
+ NULL,
+};
+ATTRIBUTE_GROUPS(zonefs_sysfs);
+
+static void zonefs_sysfs_sb_release(struct kobject *kobj)
+{
+ struct zonefs_sb_info *sbi =
+ container_of(kobj, struct zonefs_sb_info, s_kobj);
+
+ complete(&sbi->s_kobj_unregister);
+}
+
+static const struct sysfs_ops zonefs_sysfs_attr_ops = {
+ .show = zonefs_sysfs_attr_show,
+};
+
+static struct kobj_type zonefs_sb_ktype = {
+ .default_groups = zonefs_sysfs_groups,
+ .sysfs_ops = &zonefs_sysfs_attr_ops,
+ .release = zonefs_sysfs_sb_release,
+};
+
+static struct kobject *zonefs_sysfs_root;
+
+int zonefs_sysfs_register(struct super_block *sb)
+{
+ struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+ int ret;
+
+ init_completion(&sbi->s_kobj_unregister);
+ ret = kobject_init_and_add(&sbi->s_kobj, &zonefs_sb_ktype,
+ zonefs_sysfs_root, "%s", sb->s_id);
+ if (ret) {
+ kobject_put(&sbi->s_kobj);
+ wait_for_completion(&sbi->s_kobj_unregister);
+ return ret;
+ }
+
+ sbi->s_sysfs_registered = true;
+
+ return 0;
+}
+
+void zonefs_sysfs_unregister(struct super_block *sb)
+{
+ struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+
+ if (!sbi || !sbi->s_sysfs_registered)
+ return;
+
+ kobject_del(&sbi->s_kobj);
+ kobject_put(&sbi->s_kobj);
+ wait_for_completion(&sbi->s_kobj_unregister);
+}
+
+int __init zonefs_sysfs_init(void)
+{
+ zonefs_sysfs_root = kobject_create_and_add("zonefs", fs_kobj);
+ if (!zonefs_sysfs_root)
+ return -ENOMEM;
+
+ return 0;
+}
+
+void zonefs_sysfs_exit(void)
+{
+ kobject_put(zonefs_sysfs_root);
+ zonefs_sysfs_root = NULL;
+}
diff --git a/fs/zonefs/zonefs.h b/fs/zonefs/zonefs.h
index 67fd00ab173f..77d2d153c59d 100644
--- a/fs/zonefs/zonefs.h
+++ b/fs/zonefs/zonefs.h
@@ -12,6 +12,7 @@
#include <linux/uuid.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
+#include <linux/kobject.h>
/*
* Maximum length of file names: this only needs to be large enough to fit
@@ -184,6 +185,10 @@ struct zonefs_sb_info {
unsigned int s_max_wro_seq_files;
atomic_t s_wro_seq_files;
+
+ bool s_sysfs_registered;
+ struct kobject s_kobj;
+ struct completion s_kobj_unregister;
};
static inline struct zonefs_sb_info *ZONEFS_SB(struct super_block *sb)
@@ -198,4 +203,9 @@ static inline struct zonefs_sb_info *ZONEFS_SB(struct super_block *sb)
#define zonefs_warn(sb, format, args...) \
pr_warn("zonefs (%s) WARNING: " format, sb->s_id, ## args)
+int zonefs_sysfs_register(struct super_block *sb);
+void zonefs_sysfs_unregister(struct super_block *sb);
+int zonefs_sysfs_init(void);
+void zonefs_sysfs_exit(void);
+
#endif
--
2.35.1
