* [PATCH v7 2/3] erofs: add sysfs interface
[not found] <CAJfKizqxkt4BYa26cmOgCD9OFOck_J0NZ8hxCQbVoyv0j4SMJg@mail.gmail.com>
@ 2021-12-01 14:54 ` Huang Jianan
2021-12-06 9:48 ` Gao Xiang
2021-12-08 2:02 ` Gao Xiang
0 siblings, 2 replies; 3+ messages in thread
From: Huang Jianan @ 2021-12-01 14:54 UTC (permalink / raw)
To: linux-erofs, xiang, chao
Cc: linux-kernel, guoweichao, guanyuwei, yh, zhangshiming, Huang Jianan
Add sysfs interface to configure erofs related parameters later.
Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
---
since v6:
- change license to GPL-2.0-or-later
since v5:
- Add missing supported features in sysfs API documentation.
- Fill up supported feature for EROFS_FEATURE_FUNCS.
since v4:
- Resend in a clean chain.
since v3:
- Add description of sysfs in erofs documentation.
since v2:
- Check whether t in erofs_attr_store is illegal.
- Print raw value for bool entry.
since v1:
- Add sysfs API documentation.
- Use sysfs_emit over snprintf.
Documentation/ABI/testing/sysfs-fs-erofs | 7 +
Documentation/filesystems/erofs.rst | 8 +
fs/erofs/Makefile | 2 +-
fs/erofs/internal.h | 12 ++
fs/erofs/super.c | 12 ++
fs/erofs/sysfs.c | 244 +++++++++++++++++++++++
6 files changed, 284 insertions(+), 1 deletion(-)
create mode 100644 Documentation/ABI/testing/sysfs-fs-erofs
create mode 100644 fs/erofs/sysfs.c
diff --git a/Documentation/ABI/testing/sysfs-fs-erofs b/Documentation/ABI/testing/sysfs-fs-erofs
new file mode 100644
index 000000000000..a9512594dc4c
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-fs-erofs
@@ -0,0 +1,7 @@
+What: /sys/fs/erofs/features/
+Date: November 2021
+Contact: "Huang Jianan" <huangjianan@oppo.com>
+Description: Shows all enabled kernel features.
+ Supported features:
+ zero_padding, compr_cfgs, big_pcluster, chunked_file,
+ device_table, compr_head2, sb_chksum.
diff --git a/Documentation/filesystems/erofs.rst b/Documentation/filesystems/erofs.rst
index 01df283c7d04..7119aa213be7 100644
--- a/Documentation/filesystems/erofs.rst
+++ b/Documentation/filesystems/erofs.rst
@@ -93,6 +93,14 @@ dax A legacy option which is an alias for ``dax=always``.
device=%s Specify a path to an extra device to be used together.
=================== =========================================================
+Sysfs Entries
+=============
+
+Information about mounted erofs file systems can be found in /sys/fs/erofs.
+Each mounted filesystem will have a directory in /sys/fs/erofs based on its
+device name (i.e., /sys/fs/erofs/sda).
+(see also Documentation/ABI/testing/sysfs-fs-erofs)
+
On-disk details
===============
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index 756fe2d65272..8a3317e38e5a 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-$(CONFIG_EROFS_FS) += erofs.o
-erofs-objs := super.o inode.o data.o namei.o dir.o utils.o pcpubuf.o
+erofs-objs := super.o inode.o data.o namei.o dir.o utils.o pcpubuf.o sysfs.o
erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
erofs-$(CONFIG_EROFS_FS_ZIP) += decompressor.o zmap.o zdata.o
erofs-$(CONFIG_EROFS_FS_ZIP_LZMA) += decompressor_lzma.o
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 273754e7b340..43f0332fa489 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -134,6 +134,10 @@ struct erofs_sb_info {
u8 volume_name[16]; /* volume name */
u32 feature_compat;
u32 feature_incompat;
+
+ /* sysfs support */
+ struct kobject s_kobj; /* /sys/fs/erofs/<devname> */
+ struct completion s_kobj_unregister;
};
#define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
@@ -261,7 +265,9 @@ static inline bool erofs_sb_has_##name(struct erofs_sb_info *sbi) \
EROFS_FEATURE_FUNCS(zero_padding, incompat, INCOMPAT_ZERO_PADDING)
EROFS_FEATURE_FUNCS(compr_cfgs, incompat, INCOMPAT_COMPR_CFGS)
EROFS_FEATURE_FUNCS(big_pcluster, incompat, INCOMPAT_BIG_PCLUSTER)
+EROFS_FEATURE_FUNCS(chunked_file, incompat, INCOMPAT_CHUNKED_FILE)
EROFS_FEATURE_FUNCS(device_table, incompat, INCOMPAT_DEVICE_TABLE)
+EROFS_FEATURE_FUNCS(compr_head2, incompat, INCOMPAT_COMPR_HEAD2)
EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
/* atomic flag definitions */
@@ -498,6 +504,12 @@ int erofs_pcpubuf_growsize(unsigned int nrpages);
void erofs_pcpubuf_init(void);
void erofs_pcpubuf_exit(void);
+/* sysfs.c */
+int erofs_register_sysfs(struct super_block *sb);
+void erofs_unregister_sysfs(struct super_block *sb);
+int __init erofs_init_sysfs(void);
+void erofs_exit_sysfs(void);
+
/* utils.c / zdata.c */
struct page *erofs_allocpage(struct page **pagepool, gfp_t gfp);
static inline void erofs_pagepool_add(struct page **pagepool,
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 6a969b1e0ee6..abc1da5d1719 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -695,6 +695,10 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
if (err)
return err;
+ err = erofs_register_sysfs(sb);
+ if (err)
+ return err;
+
erofs_info(sb, "mounted with root inode @ nid %llu.", ROOT_NID(sbi));
return 0;
}
@@ -808,6 +812,7 @@ static void erofs_put_super(struct super_block *sb)
DBG_BUGON(!sbi);
+ erofs_unregister_sysfs(sb);
erofs_shrinker_unregister(sb);
#ifdef CONFIG_EROFS_FS_ZIP
iput(sbi->managed_cache);
@@ -852,6 +857,10 @@ static int __init erofs_module_init(void)
if (err)
goto zip_err;
+ err = erofs_init_sysfs();
+ if (err)
+ goto sysfs_err;
+
err = register_filesystem(&erofs_fs_type);
if (err)
goto fs_err;
@@ -859,6 +868,8 @@ static int __init erofs_module_init(void)
return 0;
fs_err:
+ erofs_exit_sysfs();
+sysfs_err:
z_erofs_exit_zip_subsystem();
zip_err:
z_erofs_lzma_exit();
@@ -877,6 +888,7 @@ static void __exit erofs_module_exit(void)
/* Ensure all RCU free inodes / pclusters are safe to be destroyed. */
rcu_barrier();
+ erofs_exit_sysfs();
z_erofs_exit_zip_subsystem();
z_erofs_lzma_exit();
erofs_exit_shrinker();
diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c
new file mode 100644
index 000000000000..ca18c5dce493
--- /dev/null
+++ b/fs/erofs/sysfs.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C), 2008-2021, OPPO Mobile Comm Corp., Ltd.
+ * https://www.oppo.com/
+ */
+#include <linux/sysfs.h>
+#include <linux/kobject.h>
+
+#include "internal.h"
+
+enum {
+ attr_feature,
+ attr_pointer_ui,
+ attr_pointer_bool,
+};
+
+enum {
+ struct_erofs_sb_info,
+};
+
+struct erofs_attr {
+ struct attribute attr;
+ short attr_id;
+ int struct_type;
+ int offset;
+};
+
+#define EROFS_ATTR(_name, _mode, _id) \
+static struct erofs_attr erofs_attr_##_name = { \
+ .attr = {.name = __stringify(_name), .mode = _mode }, \
+ .attr_id = attr_##_id, \
+}
+#define EROFS_ATTR_FUNC(_name, _mode) EROFS_ATTR(_name, _mode, _name)
+#define EROFS_ATTR_FEATURE(_name) EROFS_ATTR(_name, 0444, feature)
+
+#define EROFS_ATTR_OFFSET(_name, _mode, _id, _struct) \
+static struct erofs_attr erofs_attr_##_name = { \
+ .attr = {.name = __stringify(_name), .mode = _mode }, \
+ .attr_id = attr_##_id, \
+ .struct_type = struct_##_struct, \
+ .offset = offsetof(struct _struct, _name),\
+}
+
+#define EROFS_ATTR_RW(_name, _id, _struct) \
+ EROFS_ATTR_OFFSET(_name, 0644, _id, _struct)
+
+#define EROFS_RO_ATTR(_name, _id, _struct) \
+ EROFS_ATTR_OFFSET(_name, 0444, _id, _struct)
+
+#define EROFS_ATTR_RW_UI(_name, _struct) \
+ EROFS_ATTR_RW(_name, pointer_ui, _struct)
+
+#define EROFS_ATTR_RW_BOOL(_name, _struct) \
+ EROFS_ATTR_RW(_name, pointer_bool, _struct)
+
+#define ATTR_LIST(name) (&erofs_attr_##name.attr)
+
+static struct attribute *erofs_attrs[] = {
+ NULL,
+};
+ATTRIBUTE_GROUPS(erofs);
+
+/* Features this copy of erofs supports */
+EROFS_ATTR_FEATURE(zero_padding);
+EROFS_ATTR_FEATURE(compr_cfgs);
+EROFS_ATTR_FEATURE(big_pcluster);
+EROFS_ATTR_FEATURE(chunked_file);
+EROFS_ATTR_FEATURE(device_table);
+EROFS_ATTR_FEATURE(compr_head2);
+EROFS_ATTR_FEATURE(sb_chksum);
+
+static struct attribute *erofs_feat_attrs[] = {
+ ATTR_LIST(zero_padding),
+ ATTR_LIST(compr_cfgs),
+ ATTR_LIST(big_pcluster),
+ ATTR_LIST(chunked_file),
+ ATTR_LIST(device_table),
+ ATTR_LIST(compr_head2),
+ ATTR_LIST(sb_chksum),
+ NULL,
+};
+ATTRIBUTE_GROUPS(erofs_feat);
+
+static unsigned char *__struct_ptr(struct erofs_sb_info *sbi,
+ int struct_type, int offset)
+{
+ if (struct_type == struct_erofs_sb_info)
+ return (unsigned char *)sbi + offset;
+ return NULL;
+}
+
+static ssize_t erofs_attr_show(struct kobject *kobj,
+ struct attribute *attr, char *buf)
+{
+ struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
+ s_kobj);
+ struct erofs_attr *a = container_of(attr, struct erofs_attr, attr);
+ unsigned char *ptr = __struct_ptr(sbi, a->struct_type, a->offset);
+
+ switch (a->attr_id) {
+ case attr_feature:
+ return sysfs_emit(buf, "supported\n");
+ case attr_pointer_ui:
+ if (!ptr)
+ return 0;
+ return sysfs_emit(buf, "%u\n", *(unsigned int *)ptr);
+ case attr_pointer_bool:
+ if (!ptr)
+ return 0;
+ return sysfs_emit(buf, "%d\n", *(bool *)ptr);
+ }
+
+ return 0;
+}
+
+static ssize_t erofs_attr_store(struct kobject *kobj, struct attribute *attr,
+ const char *buf, size_t len)
+{
+ struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
+ s_kobj);
+ struct erofs_attr *a = container_of(attr, struct erofs_attr, attr);
+ unsigned char *ptr = __struct_ptr(sbi, a->struct_type, a->offset);
+ unsigned long t;
+ int ret;
+
+ switch (a->attr_id) {
+ case attr_pointer_ui:
+ if (!ptr)
+ return 0;
+ ret = kstrtoul(skip_spaces(buf), 0, &t);
+ if (ret)
+ return ret;
+ if (t > UINT_MAX)
+ return -EINVAL;
+ *(unsigned int *)ptr = t;
+ return len;
+ case attr_pointer_bool:
+ if (!ptr)
+ return 0;
+ ret = kstrtoul(skip_spaces(buf), 0, &t);
+ if (ret)
+ return ret;
+ if (t != 0 && t != 1)
+ return -EINVAL;
+ *(bool *)ptr = !!t;
+ return len;
+ }
+
+ return 0;
+}
+
+static void erofs_sb_release(struct kobject *kobj)
+{
+ struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
+ s_kobj);
+ complete(&sbi->s_kobj_unregister);
+}
+
+static const struct sysfs_ops erofs_attr_ops = {
+ .show = erofs_attr_show,
+ .store = erofs_attr_store,
+};
+
+static struct kobj_type erofs_sb_ktype = {
+ .default_groups = erofs_groups,
+ .sysfs_ops = &erofs_attr_ops,
+ .release = erofs_sb_release,
+};
+
+static struct kobj_type erofs_ktype = {
+ .sysfs_ops = &erofs_attr_ops,
+};
+
+static struct kset erofs_root = {
+ .kobj = {.ktype = &erofs_ktype},
+};
+
+static struct kobj_type erofs_feat_ktype = {
+ .default_groups = erofs_feat_groups,
+ .sysfs_ops = &erofs_attr_ops,
+};
+
+static struct kobject erofs_feat = {
+ .kset = &erofs_root,
+};
+
+int erofs_register_sysfs(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ int err;
+
+ sbi->s_kobj.kset = &erofs_root;
+ init_completion(&sbi->s_kobj_unregister);
+ err = kobject_init_and_add(&sbi->s_kobj, &erofs_sb_ktype, NULL,
+ "%s", sb->s_id);
+ if (err)
+ goto put_sb_kobj;
+
+ return 0;
+
+put_sb_kobj:
+ kobject_put(&sbi->s_kobj);
+ wait_for_completion(&sbi->s_kobj_unregister);
+ return err;
+}
+
+void erofs_unregister_sysfs(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+
+ kobject_del(&sbi->s_kobj);
+ kobject_put(&sbi->s_kobj);
+ wait_for_completion(&sbi->s_kobj_unregister);
+}
+
+int __init erofs_init_sysfs(void)
+{
+ int ret;
+
+ kobject_set_name(&erofs_root.kobj, "erofs");
+ erofs_root.kobj.parent = fs_kobj;
+ ret = kset_register(&erofs_root);
+ if (ret)
+ goto root_err;
+
+ ret = kobject_init_and_add(&erofs_feat, &erofs_feat_ktype,
+ NULL, "features");
+ if (ret)
+ goto feat_err;
+
+ return ret;
+
+feat_err:
+ kobject_put(&erofs_feat);
+ kset_unregister(&erofs_root);
+root_err:
+ return ret;
+}
+
+void erofs_exit_sysfs(void)
+{
+ kobject_put(&erofs_feat);
+ kset_unregister(&erofs_root);
+}
--
2.25.1
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