[PATCH 1/2] f2fs: expose /sys/fs/f2fs/features

[PATCH 1/2] f2fs: expose /sys/fs/f2fs/features

[Jaegeuk Kim]

This patch exposes what features are supported by current f2fs build to sysfs
entry.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/f2fs.h  |   6 +++
 fs/f2fs/file.c  |   3 +-
 fs/f2fs/sysfs.c | 114 +++++++++++++++++++++++++++++++++++++++++++-------------
 3 files changed, 96 insertions(+), 27 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 1833eefe47b3..a336021b777f 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2864,6 +2864,12 @@ static inline int f2fs_sb_has_project_quota(struct super_block *sb)
 	return F2FS_HAS_FEATURE(sb, F2FS_FEATURE_PRJQUOTA);
 }
 
+static inline int f2fs_sb_support_atomic_write(void)
+{
+	/* Validated with sqlite */
+	return 1;
+}
+
 #ifdef CONFIG_BLK_DEV_ZONED
 static inline int get_blkz_type(struct f2fs_sb_info *sbi,
 			struct block_device *bdev, block_t blkaddr)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index e4a45f02cd4e..0f4dbeb61845 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2384,7 +2384,8 @@ static int f2fs_ioc_get_features(struct file *filp, unsigned long arg)
 	u32 sb_feature = le32_to_cpu(F2FS_I_SB(inode)->raw_super->feature);
 
 	/* Must validate to set it with SQLite behavior in Android. */
-	sb_feature |= F2FS_FEATURE_ATOMIC_WRITE;
+	if (f2fs_sb_support_atomic_write())
+		sb_feature |= F2FS_FEATURE_ATOMIC_WRITE;
 
 	return put_user(sb_feature, (u32 __user *)arg);
 }
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 71191d89917d..0bd57e8769c6 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -18,7 +18,6 @@
 #include "gc.h"
 
 static struct proc_dir_entry *f2fs_proc_root;
-static struct kset *f2fs_kset;
 
 /* Sysfs support for f2fs */
 enum {
@@ -41,6 +40,7 @@ struct f2fs_attr {
 			 const char *, size_t);
 	int struct_type;
 	int offset;
+	int id;
 };
 
 static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int struct_type)
@@ -155,6 +155,24 @@ static void f2fs_sb_release(struct kobject *kobj)
 	complete(&sbi->s_kobj_unregister);
 }
 
+enum feat_id {
+	FEAT_CRYPTO = 0,
+	FEAT_BLKZONED,
+	FEAT_ATOMIC_WRITE,
+};
+
+static ssize_t f2fs_feature_show(struct f2fs_attr *a,
+		struct f2fs_sb_info *sbi, char *buf)
+{
+	switch (a->id) {
+	case FEAT_CRYPTO:
+	case FEAT_BLKZONED:
+	case FEAT_ATOMIC_WRITE:
+		return snprintf(buf, PAGE_SIZE, "supported\n");
+	}
+	return 0;
+}
+
 #define F2FS_ATTR_OFFSET(_struct_type, _name, _mode, _show, _store, _offset) \
 static struct f2fs_attr f2fs_attr_##_name = {			\
 	.attr = {.name = __stringify(_name), .mode = _mode },	\
@@ -172,6 +190,13 @@ static struct f2fs_attr f2fs_attr_##_name = {			\
 #define F2FS_GENERAL_RO_ATTR(name) \
 static struct f2fs_attr f2fs_attr_##name = __ATTR(name, 0444, name##_show, NULL)
 
+#define F2FS_FEATURE_RO_ATTR(_name, _id)			\
+static struct f2fs_attr f2fs_attr_##_name = {			\
+	.attr = {.name = __stringify(_name), .mode = 0444 },	\
+	.show	= f2fs_feature_show,				\
+	.id	= _id,						\
+}
+
 F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_min_sleep_time, min_sleep_time);
 F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_max_sleep_time, max_sleep_time);
 F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time);
@@ -197,6 +222,14 @@ F2FS_RW_ATTR(FAULT_INFO_TYPE, f2fs_fault_info, inject_type, inject_type);
 #endif
 F2FS_GENERAL_RO_ATTR(lifetime_write_kbytes);
 
+#ifdef CONFIG_F2FS_FS_ENCRYPTION
+F2FS_FEATURE_RO_ATTR(encryption, FEAT_CRYPTO);
+#endif
+#ifdef CONFIG_BLK_DEV_ZONED
+F2FS_FEATURE_RO_ATTR(block_zoned, FEAT_BLKZONED);
+#endif
+F2FS_FEATURE_RO_ATTR(atomic_write, FEAT_ATOMIC_WRITE);
+
 #define ATTR_LIST(name) (&f2fs_attr_##name.attr)
 static struct attribute *f2fs_attrs[] = {
 	ATTR_LIST(gc_min_sleep_time),
@@ -226,17 +259,45 @@ static struct attribute *f2fs_attrs[] = {
 	NULL,
 };
 
+static struct attribute *f2fs_feat_attrs[] = {
+#ifdef CONFIG_F2FS_FS_ENCRYPTION
+	ATTR_LIST(encryption),
+#endif
+#ifdef CONFIG_BLK_DEV_ZONED
+	ATTR_LIST(block_zoned),
+#endif
+	ATTR_LIST(atomic_write),
+	NULL,
+};
+
 static const struct sysfs_ops f2fs_attr_ops = {
 	.show	= f2fs_attr_show,
 	.store	= f2fs_attr_store,
 };
 
-static struct kobj_type f2fs_ktype = {
+static struct kobj_type f2fs_sb_ktype = {
 	.default_attrs	= f2fs_attrs,
 	.sysfs_ops	= &f2fs_attr_ops,
 	.release	= f2fs_sb_release,
 };
 
+static struct kobj_type f2fs_ktype = {
+	.sysfs_ops	= &f2fs_attr_ops,
+};
+
+static struct kset f2fs_kset = {
+	.kobj   = {.ktype = &f2fs_ktype},
+};
+
+static struct kobj_type f2fs_feat_ktype = {
+	.default_attrs	= f2fs_feat_attrs,
+	.sysfs_ops	= &f2fs_attr_ops,
+};
+
+static struct kobject f2fs_feat = {
+	.kset	= &f2fs_kset,
+};
+
 static int segment_info_seq_show(struct seq_file *seq, void *offset)
 {
 	struct super_block *sb = seq->private;
@@ -306,18 +367,29 @@ F2FS_PROC_FILE_DEF(segment_bits);
 
 int __init f2fs_register_sysfs(void)
 {
-	f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
+	int ret;
 
-	f2fs_kset = kset_create_and_add("f2fs", NULL, fs_kobj);
-	if (!f2fs_kset)
-		return -ENOMEM;
-	return 0;
+	kobject_set_name(&f2fs_kset.kobj, "f2fs");
+	f2fs_kset.kobj.parent = fs_kobj;
+	ret = kset_register(&f2fs_kset);
+	if (ret)
+		return ret;
+
+	ret = kobject_init_and_add(&f2fs_feat, &f2fs_feat_ktype,
+				   NULL, "features");
+	if (ret)
+		kset_unregister(&f2fs_kset);
+	else
+		f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
+	return ret;
 }
 
 void f2fs_unregister_sysfs(void)
 {
-	kset_unregister(f2fs_kset);
+	kobject_put(&f2fs_feat);
+	kset_unregister(&f2fs_kset);
 	remove_proc_entry("fs/f2fs", NULL);
+	f2fs_proc_root = NULL;
 }
 
 int f2fs_init_sysfs(struct f2fs_sb_info *sbi)
@@ -325,6 +397,13 @@ int f2fs_init_sysfs(struct f2fs_sb_info *sbi)
 	struct super_block *sb = sbi->sb;
 	int err;
 
+	sbi->s_kobj.kset = &f2fs_kset;
+	init_completion(&sbi->s_kobj_unregister);
+	err = kobject_init_and_add(&sbi->s_kobj, &f2fs_sb_ktype, NULL,
+				"%s", sb->s_id);
+	if (err)
+		return err;
+
 	if (f2fs_proc_root)
 		sbi->s_proc = proc_mkdir(sb->s_id, f2fs_proc_root);
 
@@ -334,32 +413,15 @@ int f2fs_init_sysfs(struct f2fs_sb_info *sbi)
 		proc_create_data("segment_bits", S_IRUGO, sbi->s_proc,
 				 &f2fs_seq_segment_bits_fops, sb);
 	}
-
-	sbi->s_kobj.kset = f2fs_kset;
-	init_completion(&sbi->s_kobj_unregister);
-	err = kobject_init_and_add(&sbi->s_kobj, &f2fs_ktype, NULL,
-							"%s", sb->s_id);
-	if (err)
-		goto err_out;
 	return 0;
-err_out:
-	if (sbi->s_proc) {
-		remove_proc_entry("segment_info", sbi->s_proc);
-		remove_proc_entry("segment_bits", sbi->s_proc);
-		remove_proc_entry(sb->s_id, f2fs_proc_root);
-	}
-	return err;
 }
 
 void f2fs_exit_sysfs(struct f2fs_sb_info *sbi)
 {
-	kobject_del(&sbi->s_kobj);
-	kobject_put(&sbi->s_kobj);
-	wait_for_completion(&sbi->s_kobj_unregister);
-
 	if (sbi->s_proc) {
 		remove_proc_entry("segment_info", sbi->s_proc);
 		remove_proc_entry("segment_bits", sbi->s_proc);
 		remove_proc_entry(sbi->sb->s_id, f2fs_proc_root);
 	}
+	kobject_del(&sbi->s_kobj);
 }
-- 
2.13.0.rc1.294.g07d810a77f-goog

[PATCH 2/2] f2fs: don't give partially written atomic data from process crash

[Jaegeuk Kim]

This patch resolves the below scenario.

== Process 1 ==     == Process 2 ==
open(w)             open(rw)
begin
write(new_#1)
process_crash
  f_op->flush
  locks_remove_posix
  f_op>release
                    read (new_#1)

In order to avoid corrupted database caused by new_#1, we must do roll-back
at process_crash time. In order to check that, this patch keeps task which
triggers transaction begin, and does roll-back in f_op->flush before removing
file locks.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/f2fs.h |  1 +
 fs/f2fs/file.c | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index a336021b777f..3e48c2ac2f21 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -565,6 +565,7 @@ struct f2fs_inode_info {
 	struct list_head dirty_list;	/* dirty list for dirs and files */
 	struct list_head gdirty_list;	/* linked in global dirty list */
 	struct list_head inmem_pages;	/* inmemory pages managed by f2fs */
+	struct task_struct *inmem_task;	/* store inmemory task */
 	struct mutex inmem_lock;	/* lock for inmemory pages */
 	struct extent_tree *extent_tree;	/* cached extent_tree entry */
 	struct rw_semaphore dio_rwsem[2];/* avoid racing between dio and gc */
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 0f4dbeb61845..cb0a013859e6 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1502,6 +1502,22 @@ static int f2fs_release_file(struct inode *inode, struct file *filp)
 	return 0;
 }
 
+static int f2fs_file_flush(struct file *file, fl_owner_t id)
+{
+	struct inode *inode = file_inode(file);
+
+	/*
+	 * If the process doing a transaction is crashed, we should do
+	 * roll-back. Otherwise, other reader/write can see corrupted database
+	 * until all the writers close its file. Since this should be done
+	 * before dropping file lock, it needs to do in ->flush.
+	 */
+	if (f2fs_is_atomic_file(inode) &&
+			F2FS_I(inode)->inmem_task == current)
+		drop_inmem_pages(inode);
+	return 0;
+}
+
 static int f2fs_ioc_getflags(struct file *filp, unsigned long arg)
 {
 	struct inode *inode = file_inode(filp);
@@ -1608,6 +1624,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
 	}
 
 inc_stat:
+	F2FS_I(inode)->inmem_task = current;
 	stat_inc_atomic_write(inode);
 	stat_update_max_atomic_write(inode);
 out:
@@ -2514,6 +2531,7 @@ const struct file_operations f2fs_file_operations = {
 	.open		= f2fs_file_open,
 	.release	= f2fs_release_file,
 	.mmap		= f2fs_file_mmap,
+	.flush		= f2fs_file_flush,
 	.fsync		= f2fs_sync_file,
 	.fallocate	= f2fs_fallocate,
 	.unlocked_ioctl	= f2fs_ioctl,
-- 
2.13.0.rc1.294.g07d810a77f-goog

Re: [f2fs-dev] [PATCH 2/2] f2fs: don't give partially written atomic data from process crash

[Chao Yu]

On 2017/7/26 9:29, Jaegeuk Kim wrote:
> This patch resolves the below scenario.
> 
> == Process 1 ==     == Process 2 ==
> open(w)             open(rw)
> begin
> write(new_#1)
> process_crash
>   f_op->flush
>   locks_remove_posix
>   f_op>release
>                     read (new_#1)
> 
> In order to avoid corrupted database caused by new_#1, we must do roll-back
> at process_crash time. In order to check that, this patch keeps task which
> triggers transaction begin, and does roll-back in f_op->flush before removing
> file locks.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,

> ---
>  fs/f2fs/f2fs.h |  1 +
>  fs/f2fs/file.c | 18 ++++++++++++++++++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index a336021b777f..3e48c2ac2f21 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -565,6 +565,7 @@ struct f2fs_inode_info {
>  	struct list_head dirty_list;	/* dirty list for dirs and files */
>  	struct list_head gdirty_list;	/* linked in global dirty list */
>  	struct list_head inmem_pages;	/* inmemory pages managed by f2fs */
> +	struct task_struct *inmem_task;	/* store inmemory task */
>  	struct mutex inmem_lock;	/* lock for inmemory pages */
>  	struct extent_tree *extent_tree;	/* cached extent_tree entry */
>  	struct rw_semaphore dio_rwsem[2];/* avoid racing between dio and gc */
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 0f4dbeb61845..cb0a013859e6 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1502,6 +1502,22 @@ static int f2fs_release_file(struct inode *inode, struct file *filp)
>  	return 0;
>  }
>  
> +static int f2fs_file_flush(struct file *file, fl_owner_t id)
> +{
> +	struct inode *inode = file_inode(file);
> +
> +	/*
> +	 * If the process doing a transaction is crashed, we should do
> +	 * roll-back. Otherwise, other reader/write can see corrupted database
> +	 * until all the writers close its file. Since this should be done
> +	 * before dropping file lock, it needs to do in ->flush.
> +	 */
> +	if (f2fs_is_atomic_file(inode) &&
> +			F2FS_I(inode)->inmem_task == current)
> +		drop_inmem_pages(inode);
> +	return 0;
> +}
> +
>  static int f2fs_ioc_getflags(struct file *filp, unsigned long arg)
>  {
>  	struct inode *inode = file_inode(filp);
> @@ -1608,6 +1624,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
>  	}
>  
>  inc_stat:
> +	F2FS_I(inode)->inmem_task = current;
>  	stat_inc_atomic_write(inode);
>  	stat_update_max_atomic_write(inode);
>  out:
> @@ -2514,6 +2531,7 @@ const struct file_operations f2fs_file_operations = {
>  	.open		= f2fs_file_open,
>  	.release	= f2fs_release_file,
>  	.mmap		= f2fs_file_mmap,
> +	.flush		= f2fs_file_flush,
>  	.fsync		= f2fs_sync_file,
>  	.fallocate	= f2fs_fallocate,
>  	.unlocked_ioctl	= f2fs_ioctl,
> 

Re: [f2fs-dev] [PATCH 1/2] f2fs: expose /sys/fs/f2fs/features

[Chao Yu]

On 2017/7/26 9:29, Jaegeuk Kim wrote:
> This patch exposes what features are supported by current f2fs build to sysfs
> entry.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Minor thing, can you exchange below function name to follow ext4:
f2fs_init_sysfs <-> f2fs_register_sysfs
f2fs_exit_sysfs <-> f2fs_unregister_sysfs

Thanks,

> ---
>  fs/f2fs/f2fs.h  |   6 +++
>  fs/f2fs/file.c  |   3 +-
>  fs/f2fs/sysfs.c | 114 +++++++++++++++++++++++++++++++++++++++++++-------------
>  3 files changed, 96 insertions(+), 27 deletions(-)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 1833eefe47b3..a336021b777f 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -2864,6 +2864,12 @@ static inline int f2fs_sb_has_project_quota(struct super_block *sb)
>  	return F2FS_HAS_FEATURE(sb, F2FS_FEATURE_PRJQUOTA);
>  }
>  
> +static inline int f2fs_sb_support_atomic_write(void)
> +{
> +	/* Validated with sqlite */
> +	return 1;
> +}
> +
>  #ifdef CONFIG_BLK_DEV_ZONED
>  static inline int get_blkz_type(struct f2fs_sb_info *sbi,
>  			struct block_device *bdev, block_t blkaddr)
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index e4a45f02cd4e..0f4dbeb61845 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -2384,7 +2384,8 @@ static int f2fs_ioc_get_features(struct file *filp, unsigned long arg)
>  	u32 sb_feature = le32_to_cpu(F2FS_I_SB(inode)->raw_super->feature);
>  
>  	/* Must validate to set it with SQLite behavior in Android. */
> -	sb_feature |= F2FS_FEATURE_ATOMIC_WRITE;
> +	if (f2fs_sb_support_atomic_write())
> +		sb_feature |= F2FS_FEATURE_ATOMIC_WRITE;
>  
>  	return put_user(sb_feature, (u32 __user *)arg);
>  }
> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> index 71191d89917d..0bd57e8769c6 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -18,7 +18,6 @@
>  #include "gc.h"
>  
>  static struct proc_dir_entry *f2fs_proc_root;
> -static struct kset *f2fs_kset;
>  
>  /* Sysfs support for f2fs */
>  enum {
> @@ -41,6 +40,7 @@ struct f2fs_attr {
>  			 const char *, size_t);
>  	int struct_type;
>  	int offset;
> +	int id;
>  };
>  
>  static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int struct_type)
> @@ -155,6 +155,24 @@ static void f2fs_sb_release(struct kobject *kobj)
>  	complete(&sbi->s_kobj_unregister);
>  }
>  
> +enum feat_id {
> +	FEAT_CRYPTO = 0,
> +	FEAT_BLKZONED,
> +	FEAT_ATOMIC_WRITE,
> +};
> +
> +static ssize_t f2fs_feature_show(struct f2fs_attr *a,
> +		struct f2fs_sb_info *sbi, char *buf)
> +{
> +	switch (a->id) {
> +	case FEAT_CRYPTO:
> +	case FEAT_BLKZONED:
> +	case FEAT_ATOMIC_WRITE:
> +		return snprintf(buf, PAGE_SIZE, "supported\n");
> +	}
> +	return 0;
> +}
> +
>  #define F2FS_ATTR_OFFSET(_struct_type, _name, _mode, _show, _store, _offset) \
>  static struct f2fs_attr f2fs_attr_##_name = {			\
>  	.attr = {.name = __stringify(_name), .mode = _mode },	\
> @@ -172,6 +190,13 @@ static struct f2fs_attr f2fs_attr_##_name = {			\
>  #define F2FS_GENERAL_RO_ATTR(name) \
>  static struct f2fs_attr f2fs_attr_##name = __ATTR(name, 0444, name##_show, NULL)
>  
> +#define F2FS_FEATURE_RO_ATTR(_name, _id)			\
> +static struct f2fs_attr f2fs_attr_##_name = {			\
> +	.attr = {.name = __stringify(_name), .mode = 0444 },	\
> +	.show	= f2fs_feature_show,				\
> +	.id	= _id,						\
> +}
> +
>  F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_min_sleep_time, min_sleep_time);
>  F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_max_sleep_time, max_sleep_time);
>  F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time);
> @@ -197,6 +222,14 @@ F2FS_RW_ATTR(FAULT_INFO_TYPE, f2fs_fault_info, inject_type, inject_type);
>  #endif
>  F2FS_GENERAL_RO_ATTR(lifetime_write_kbytes);
>  
> +#ifdef CONFIG_F2FS_FS_ENCRYPTION
> +F2FS_FEATURE_RO_ATTR(encryption, FEAT_CRYPTO);
> +#endif
> +#ifdef CONFIG_BLK_DEV_ZONED
> +F2FS_FEATURE_RO_ATTR(block_zoned, FEAT_BLKZONED);
> +#endif
> +F2FS_FEATURE_RO_ATTR(atomic_write, FEAT_ATOMIC_WRITE);
> +
>  #define ATTR_LIST(name) (&f2fs_attr_##name.attr)
>  static struct attribute *f2fs_attrs[] = {
>  	ATTR_LIST(gc_min_sleep_time),
> @@ -226,17 +259,45 @@ static struct attribute *f2fs_attrs[] = {
>  	NULL,
>  };
>  
> +static struct attribute *f2fs_feat_attrs[] = {
> +#ifdef CONFIG_F2FS_FS_ENCRYPTION
> +	ATTR_LIST(encryption),
> +#endif
> +#ifdef CONFIG_BLK_DEV_ZONED
> +	ATTR_LIST(block_zoned),
> +#endif
> +	ATTR_LIST(atomic_write),
> +	NULL,
> +};
> +
>  static const struct sysfs_ops f2fs_attr_ops = {
>  	.show	= f2fs_attr_show,
>  	.store	= f2fs_attr_store,
>  };
>  
> -static struct kobj_type f2fs_ktype = {
> +static struct kobj_type f2fs_sb_ktype = {
>  	.default_attrs	= f2fs_attrs,
>  	.sysfs_ops	= &f2fs_attr_ops,
>  	.release	= f2fs_sb_release,
>  };
>  
> +static struct kobj_type f2fs_ktype = {
> +	.sysfs_ops	= &f2fs_attr_ops,
> +};
> +
> +static struct kset f2fs_kset = {
> +	.kobj   = {.ktype = &f2fs_ktype},
> +};
> +
> +static struct kobj_type f2fs_feat_ktype = {
> +	.default_attrs	= f2fs_feat_attrs,
> +	.sysfs_ops	= &f2fs_attr_ops,
> +};
> +
> +static struct kobject f2fs_feat = {
> +	.kset	= &f2fs_kset,
> +};
> +
>  static int segment_info_seq_show(struct seq_file *seq, void *offset)
>  {
>  	struct super_block *sb = seq->private;
> @@ -306,18 +367,29 @@ F2FS_PROC_FILE_DEF(segment_bits);
>  
>  int __init f2fs_register_sysfs(void)
>  {
> -	f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
> +	int ret;
>  
> -	f2fs_kset = kset_create_and_add("f2fs", NULL, fs_kobj);
> -	if (!f2fs_kset)
> -		return -ENOMEM;
> -	return 0;
> +	kobject_set_name(&f2fs_kset.kobj, "f2fs");
> +	f2fs_kset.kobj.parent = fs_kobj;
> +	ret = kset_register(&f2fs_kset);
> +	if (ret)
> +		return ret;
> +
> +	ret = kobject_init_and_add(&f2fs_feat, &f2fs_feat_ktype,
> +				   NULL, "features");
> +	if (ret)
> +		kset_unregister(&f2fs_kset);
> +	else
> +		f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
> +	return ret;
>  }
>  
>  void f2fs_unregister_sysfs(void)
>  {
> -	kset_unregister(f2fs_kset);
> +	kobject_put(&f2fs_feat);
> +	kset_unregister(&f2fs_kset);
>  	remove_proc_entry("fs/f2fs", NULL);
> +	f2fs_proc_root = NULL;
>  }
>  
>  int f2fs_init_sysfs(struct f2fs_sb_info *sbi)
> @@ -325,6 +397,13 @@ int f2fs_init_sysfs(struct f2fs_sb_info *sbi)
>  	struct super_block *sb = sbi->sb;
>  	int err;
>  
> +	sbi->s_kobj.kset = &f2fs_kset;
> +	init_completion(&sbi->s_kobj_unregister);
> +	err = kobject_init_and_add(&sbi->s_kobj, &f2fs_sb_ktype, NULL,
> +				"%s", sb->s_id);
> +	if (err)
> +		return err;
> +
>  	if (f2fs_proc_root)
>  		sbi->s_proc = proc_mkdir(sb->s_id, f2fs_proc_root);
>  
> @@ -334,32 +413,15 @@ int f2fs_init_sysfs(struct f2fs_sb_info *sbi)
>  		proc_create_data("segment_bits", S_IRUGO, sbi->s_proc,
>  				 &f2fs_seq_segment_bits_fops, sb);
>  	}
> -
> -	sbi->s_kobj.kset = f2fs_kset;
> -	init_completion(&sbi->s_kobj_unregister);
> -	err = kobject_init_and_add(&sbi->s_kobj, &f2fs_ktype, NULL,
> -							"%s", sb->s_id);
> -	if (err)
> -		goto err_out;
>  	return 0;
> -err_out:
> -	if (sbi->s_proc) {
> -		remove_proc_entry("segment_info", sbi->s_proc);
> -		remove_proc_entry("segment_bits", sbi->s_proc);
> -		remove_proc_entry(sb->s_id, f2fs_proc_root);
> -	}
> -	return err;
>  }
>  
>  void f2fs_exit_sysfs(struct f2fs_sb_info *sbi)
>  {
> -	kobject_del(&sbi->s_kobj);
> -	kobject_put(&sbi->s_kobj);
> -	wait_for_completion(&sbi->s_kobj_unregister);
> -
>  	if (sbi->s_proc) {
>  		remove_proc_entry("segment_info", sbi->s_proc);
>  		remove_proc_entry("segment_bits", sbi->s_proc);
>  		remove_proc_entry(sbi->sb->s_id, f2fs_proc_root);
>  	}
> +	kobject_del(&sbi->s_kobj);
>  }
> 

Re: [f2fs-dev] [PATCH 1/2] f2fs: expose /sys/fs/f2fs/features

[Jaegeuk Kim]

On 07/26, Chao Yu wrote:
> On 2017/7/26 9:29, Jaegeuk Kim wrote:
> > This patch exposes what features are supported by current f2fs build to sysfs
> > entry.
> > 
> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> 
> Reviewed-by: Chao Yu <yuchao0@huawei.com>
> 
> Minor thing, can you exchange below function name to follow ext4:
> f2fs_init_sysfs <-> f2fs_register_sysfs
> f2fs_exit_sysfs <-> f2fs_unregister_sysfs
> 
>From 4cf8a3138f3ee171750ae279fefd4de672a0ee29 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Wed, 26 Jul 2017 11:24:13 -0700
Subject: [PATCH] f2fs: avoid naming confusion of sysfs init

This patch changes the function names of sysfs init to follow ext4.

f2fs_init_sysfs <-> f2fs_register_sysfs
f2fs_exit_sysfs <-> f2fs_unregister_sysfs

Suggested-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/f2fs.h  |  8 ++++----
 fs/f2fs/super.c | 10 +++++-----
 fs/f2fs/sysfs.c |  8 ++++----
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index d486539086b6..a1bfd0b9be44 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2820,10 +2820,10 @@ void destroy_extent_cache(void);
 /*
  * sysfs.c
  */
-int __init f2fs_register_sysfs(void);
-void f2fs_unregister_sysfs(void);
-int f2fs_init_sysfs(struct f2fs_sb_info *sbi);
-void f2fs_exit_sysfs(struct f2fs_sb_info *sbi);
+int __init f2fs_init_sysfs(void);
+void f2fs_exit_sysfs(void);
+int f2fs_register_sysfs(struct f2fs_sb_info *sbi);
+void f2fs_unregister_sysfs(struct f2fs_sb_info *sbi);
 
 /*
  * crypto support
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 1241739f4d54..12513caabe6e 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -649,7 +649,7 @@ static void f2fs_put_super(struct super_block *sb)
 
 	kfree(sbi->ckpt);
 
-	f2fs_exit_sysfs(sbi);
+	f2fs_unregister_sysfs(sbi);
 
 	sb->s_fs_info = NULL;
 	if (sbi->s_chksum_driver)
@@ -2145,7 +2145,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 		goto free_root_inode;
 	}
 
-	err = f2fs_init_sysfs(sbi);
+	err = f2fs_register_sysfs(sbi);
 	if (err)
 		goto free_root_inode;
 
@@ -2216,7 +2216,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 
 free_sysfs:
 	f2fs_sync_inode_meta(sbi);
-	f2fs_exit_sysfs(sbi);
+	f2fs_unregister_sysfs(sbi);
 free_root_inode:
 	dput(sb->s_root);
 	sb->s_root = NULL;
@@ -2334,7 +2334,7 @@ static int __init init_f2fs_fs(void)
 	err = create_extent_cache();
 	if (err)
 		goto free_checkpoint_caches;
-	err = f2fs_register_sysfs();
+	err = f2fs_init_sysfs();
 	if (err)
 		goto free_extent_cache;
 	err = register_shrinker(&f2fs_shrinker_info);
@@ -2373,7 +2373,7 @@ static void __exit exit_f2fs_fs(void)
 	f2fs_destroy_root_stats();
 	unregister_filesystem(&f2fs_fs_type);
 	unregister_shrinker(&f2fs_shrinker_info);
-	f2fs_unregister_sysfs();
+	f2fs_exit_sysfs();
 	destroy_extent_cache();
 	destroy_checkpoint_caches();
 	destroy_segment_manager_caches();
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 71191d89917d..5a78b9af92ef 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -304,7 +304,7 @@ static const struct file_operations f2fs_seq_##_name##_fops = {		\
 F2FS_PROC_FILE_DEF(segment_info);
 F2FS_PROC_FILE_DEF(segment_bits);
 
-int __init f2fs_register_sysfs(void)
+int __init f2fs_init_sysfs(void)
 {
 	f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
 
@@ -314,13 +314,13 @@ int __init f2fs_register_sysfs(void)
 	return 0;
 }
 
-void f2fs_unregister_sysfs(void)
+void f2fs_exit_sysfs(void)
 {
 	kset_unregister(f2fs_kset);
 	remove_proc_entry("fs/f2fs", NULL);
 }
 
-int f2fs_init_sysfs(struct f2fs_sb_info *sbi)
+int f2fs_register_sysfs(struct f2fs_sb_info *sbi)
 {
 	struct super_block *sb = sbi->sb;
 	int err;
@@ -351,7 +351,7 @@ int f2fs_init_sysfs(struct f2fs_sb_info *sbi)
 	return err;
 }
 
-void f2fs_exit_sysfs(struct f2fs_sb_info *sbi)
+void f2fs_unregister_sysfs(struct f2fs_sb_info *sbi)
 {
 	kobject_del(&sbi->s_kobj);
 	kobject_put(&sbi->s_kobj);
-- 
2.13.0.rc1.294.g07d810a77f-goog

Re: [f2fs-dev] [PATCH 1/2] f2fs: expose /sys/fs/f2fs/features

[Chao Yu]

On 2017/7/27 5:43, Jaegeuk Kim wrote:
> On 07/26, Chao Yu wrote:
>> On 2017/7/26 9:29, Jaegeuk Kim wrote:
>>> This patch exposes what features are supported by current f2fs build to sysfs
>>> entry.
>>>
>>> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
>>
>> Reviewed-by: Chao Yu <yuchao0@huawei.com>
>>
>> Minor thing, can you exchange below function name to follow ext4:
>> f2fs_init_sysfs <-> f2fs_register_sysfs
>> f2fs_exit_sysfs <-> f2fs_unregister_sysfs
>>
>>>From 4cf8a3138f3ee171750ae279fefd4de672a0ee29 Mon Sep 17 00:00:00 2001
> From: Jaegeuk Kim <jaegeuk@kernel.org>
> Date: Wed, 26 Jul 2017 11:24:13 -0700
> Subject: [PATCH] f2fs: avoid naming confusion of sysfs init
> 
> This patch changes the function names of sysfs init to follow ext4.
> 
> f2fs_init_sysfs <-> f2fs_register_sysfs
> f2fs_exit_sysfs <-> f2fs_unregister_sysfs
> 
> Suggested-by: Chao Yu <yuchao0@huawei.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reivewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,

> ---
>  fs/f2fs/f2fs.h  |  8 ++++----
>  fs/f2fs/super.c | 10 +++++-----
>  fs/f2fs/sysfs.c |  8 ++++----
>  3 files changed, 13 insertions(+), 13 deletions(-)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index d486539086b6..a1bfd0b9be44 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -2820,10 +2820,10 @@ void destroy_extent_cache(void);
>  /*
>   * sysfs.c
>   */
> -int __init f2fs_register_sysfs(void);
> -void f2fs_unregister_sysfs(void);
> -int f2fs_init_sysfs(struct f2fs_sb_info *sbi);
> -void f2fs_exit_sysfs(struct f2fs_sb_info *sbi);
> +int __init f2fs_init_sysfs(void);
> +void f2fs_exit_sysfs(void);
> +int f2fs_register_sysfs(struct f2fs_sb_info *sbi);
> +void f2fs_unregister_sysfs(struct f2fs_sb_info *sbi);
>  
>  /*
>   * crypto support
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 1241739f4d54..12513caabe6e 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -649,7 +649,7 @@ static void f2fs_put_super(struct super_block *sb)
>  
>  	kfree(sbi->ckpt);
>  
> -	f2fs_exit_sysfs(sbi);
> +	f2fs_unregister_sysfs(sbi);
>  
>  	sb->s_fs_info = NULL;
>  	if (sbi->s_chksum_driver)
> @@ -2145,7 +2145,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>  		goto free_root_inode;
>  	}
>  
> -	err = f2fs_init_sysfs(sbi);
> +	err = f2fs_register_sysfs(sbi);
>  	if (err)
>  		goto free_root_inode;
>  
> @@ -2216,7 +2216,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>  
>  free_sysfs:
>  	f2fs_sync_inode_meta(sbi);
> -	f2fs_exit_sysfs(sbi);
> +	f2fs_unregister_sysfs(sbi);
>  free_root_inode:
>  	dput(sb->s_root);
>  	sb->s_root = NULL;
> @@ -2334,7 +2334,7 @@ static int __init init_f2fs_fs(void)
>  	err = create_extent_cache();
>  	if (err)
>  		goto free_checkpoint_caches;
> -	err = f2fs_register_sysfs();
> +	err = f2fs_init_sysfs();
>  	if (err)
>  		goto free_extent_cache;
>  	err = register_shrinker(&f2fs_shrinker_info);
> @@ -2373,7 +2373,7 @@ static void __exit exit_f2fs_fs(void)
>  	f2fs_destroy_root_stats();
>  	unregister_filesystem(&f2fs_fs_type);
>  	unregister_shrinker(&f2fs_shrinker_info);
> -	f2fs_unregister_sysfs();
> +	f2fs_exit_sysfs();
>  	destroy_extent_cache();
>  	destroy_checkpoint_caches();
>  	destroy_segment_manager_caches();
> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> index 71191d89917d..5a78b9af92ef 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -304,7 +304,7 @@ static const struct file_operations f2fs_seq_##_name##_fops = {		\
>  F2FS_PROC_FILE_DEF(segment_info);
>  F2FS_PROC_FILE_DEF(segment_bits);
>  
> -int __init f2fs_register_sysfs(void)
> +int __init f2fs_init_sysfs(void)
>  {
>  	f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
>  
> @@ -314,13 +314,13 @@ int __init f2fs_register_sysfs(void)
>  	return 0;
>  }
>  
> -void f2fs_unregister_sysfs(void)
> +void f2fs_exit_sysfs(void)
>  {
>  	kset_unregister(f2fs_kset);
>  	remove_proc_entry("fs/f2fs", NULL);
>  }
>  
> -int f2fs_init_sysfs(struct f2fs_sb_info *sbi)
> +int f2fs_register_sysfs(struct f2fs_sb_info *sbi)
>  {
>  	struct super_block *sb = sbi->sb;
>  	int err;
> @@ -351,7 +351,7 @@ int f2fs_init_sysfs(struct f2fs_sb_info *sbi)
>  	return err;
>  }
>  
> -void f2fs_exit_sysfs(struct f2fs_sb_info *sbi)
> +void f2fs_unregister_sysfs(struct f2fs_sb_info *sbi)
>  {
>  	kobject_del(&sbi->s_kobj);
>  	kobject_put(&sbi->s_kobj);
> 

Re: [PATCH 1/2 v2] f2fs: expose /sys/fs/f2fs/features

[Jaegeuk Kim]

Change log from v1:
 - add /sys/fs/f2fs/dev/features

This patch exposes what features are supported by current f2fs build to sysfs
entry via:

/sys/fs/f2fs/features/
/sys/fs/f2fs/dev/features

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/sysfs.c | 138 +++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 112 insertions(+), 26 deletions(-)

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 5a78b9af92ef..83ab0dd73b2c 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -18,7 +18,6 @@
 #include "gc.h"
 
 static struct proc_dir_entry *f2fs_proc_root;
-static struct kset *f2fs_kset;
 
 /* Sysfs support for f2fs */
 enum {
@@ -41,6 +40,7 @@ struct f2fs_attr {
 			 const char *, size_t);
 	int struct_type;
 	int offset;
+	int id;
 };
 
 static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int struct_type)
@@ -76,6 +76,28 @@ static ssize_t lifetime_write_kbytes_show(struct f2fs_attr *a,
 			BD_PART_WRITTEN(sbi)));
 }
 
+static ssize_t features_show(struct f2fs_attr *a,
+		struct f2fs_sb_info *sbi, char *buf)
+{
+	struct super_block *sb = sbi->sb;
+	int len = 0;
+
+	if (!sb->s_bdev->bd_part)
+		return snprintf(buf, PAGE_SIZE, "0\n");
+
+	if (f2fs_sb_has_crypto(sb))
+		len += snprintf(buf, PAGE_SIZE - len, "%s\n", "encryption");
+	if (f2fs_sb_mounted_blkzoned(sb))
+		len += snprintf(buf, PAGE_SIZE - len, "%s\n", ", blkzoned");
+	if (f2fs_sb_has_extra_attr(sb))
+		len += snprintf(buf, PAGE_SIZE - len, "%s\n", ", extra_attr");
+	if (f2fs_sb_has_project_quota(sb))
+		len += snprintf(buf, PAGE_SIZE - len, "%s\n", ", projquota");
+	if (f2fs_sb_has_inode_chksum(sb))
+		len += snprintf(buf, PAGE_SIZE - len, "%s\n", ", inode_checksum");
+	return len;
+}
+
 static ssize_t f2fs_sbi_show(struct f2fs_attr *a,
 			struct f2fs_sb_info *sbi, char *buf)
 {
@@ -155,6 +177,24 @@ static void f2fs_sb_release(struct kobject *kobj)
 	complete(&sbi->s_kobj_unregister);
 }
 
+enum feat_id {
+	FEAT_CRYPTO = 0,
+	FEAT_BLKZONED,
+	FEAT_ATOMIC_WRITE,
+};
+
+static ssize_t f2fs_feature_show(struct f2fs_attr *a,
+		struct f2fs_sb_info *sbi, char *buf)
+{
+	switch (a->id) {
+	case FEAT_CRYPTO:
+	case FEAT_BLKZONED:
+	case FEAT_ATOMIC_WRITE:
+		return snprintf(buf, PAGE_SIZE, "supported\n");
+	}
+	return 0;
+}
+
 #define F2FS_ATTR_OFFSET(_struct_type, _name, _mode, _show, _store, _offset) \
 static struct f2fs_attr f2fs_attr_##_name = {			\
 	.attr = {.name = __stringify(_name), .mode = _mode },	\
@@ -172,6 +212,13 @@ static struct f2fs_attr f2fs_attr_##_name = {			\
 #define F2FS_GENERAL_RO_ATTR(name) \
 static struct f2fs_attr f2fs_attr_##name = __ATTR(name, 0444, name##_show, NULL)
 
+#define F2FS_FEATURE_RO_ATTR(_name, _id)			\
+static struct f2fs_attr f2fs_attr_##_name = {			\
+	.attr = {.name = __stringify(_name), .mode = 0444 },	\
+	.show	= f2fs_feature_show,				\
+	.id	= _id,						\
+}
+
 F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_min_sleep_time, min_sleep_time);
 F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_max_sleep_time, max_sleep_time);
 F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time);
@@ -196,6 +243,15 @@ F2FS_RW_ATTR(FAULT_INFO_RATE, f2fs_fault_info, inject_rate, inject_rate);
 F2FS_RW_ATTR(FAULT_INFO_TYPE, f2fs_fault_info, inject_type, inject_type);
 #endif
 F2FS_GENERAL_RO_ATTR(lifetime_write_kbytes);
+F2FS_GENERAL_RO_ATTR(features);
+
+#ifdef CONFIG_F2FS_FS_ENCRYPTION
+F2FS_FEATURE_RO_ATTR(encryption, FEAT_CRYPTO);
+#endif
+#ifdef CONFIG_BLK_DEV_ZONED
+F2FS_FEATURE_RO_ATTR(block_zoned, FEAT_BLKZONED);
+#endif
+F2FS_FEATURE_RO_ATTR(atomic_write, FEAT_ATOMIC_WRITE);
 
 #define ATTR_LIST(name) (&f2fs_attr_##name.attr)
 static struct attribute *f2fs_attrs[] = {
@@ -222,21 +278,50 @@ static struct attribute *f2fs_attrs[] = {
 	ATTR_LIST(inject_type),
 #endif
 	ATTR_LIST(lifetime_write_kbytes),
+	ATTR_LIST(features),
 	ATTR_LIST(reserved_blocks),
 	NULL,
 };
 
+static struct attribute *f2fs_feat_attrs[] = {
+#ifdef CONFIG_F2FS_FS_ENCRYPTION
+	ATTR_LIST(encryption),
+#endif
+#ifdef CONFIG_BLK_DEV_ZONED
+	ATTR_LIST(block_zoned),
+#endif
+	ATTR_LIST(atomic_write),
+	NULL,
+};
+
 static const struct sysfs_ops f2fs_attr_ops = {
 	.show	= f2fs_attr_show,
 	.store	= f2fs_attr_store,
 };
 
-static struct kobj_type f2fs_ktype = {
+static struct kobj_type f2fs_sb_ktype = {
 	.default_attrs	= f2fs_attrs,
 	.sysfs_ops	= &f2fs_attr_ops,
 	.release	= f2fs_sb_release,
 };
 
+static struct kobj_type f2fs_ktype = {
+	.sysfs_ops	= &f2fs_attr_ops,
+};
+
+static struct kset f2fs_kset = {
+	.kobj   = {.ktype = &f2fs_ktype},
+};
+
+static struct kobj_type f2fs_feat_ktype = {
+	.default_attrs	= f2fs_feat_attrs,
+	.sysfs_ops	= &f2fs_attr_ops,
+};
+
+static struct kobject f2fs_feat = {
+	.kset	= &f2fs_kset,
+};
+
 static int segment_info_seq_show(struct seq_file *seq, void *offset)
 {
 	struct super_block *sb = seq->private;
@@ -306,18 +391,29 @@ F2FS_PROC_FILE_DEF(segment_bits);
 
 int __init f2fs_init_sysfs(void)
 {
-	f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
+	int ret;
 
-	f2fs_kset = kset_create_and_add("f2fs", NULL, fs_kobj);
-	if (!f2fs_kset)
-		return -ENOMEM;
-	return 0;
+	kobject_set_name(&f2fs_kset.kobj, "f2fs");
+	f2fs_kset.kobj.parent = fs_kobj;
+	ret = kset_register(&f2fs_kset);
+	if (ret)
+		return ret;
+
+	ret = kobject_init_and_add(&f2fs_feat, &f2fs_feat_ktype,
+				   NULL, "features");
+	if (ret)
+		kset_unregister(&f2fs_kset);
+	else
+		f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
+	return ret;
 }
 
 void f2fs_exit_sysfs(void)
 {
-	kset_unregister(f2fs_kset);
+	kobject_put(&f2fs_feat);
+	kset_unregister(&f2fs_kset);
 	remove_proc_entry("fs/f2fs", NULL);
+	f2fs_proc_root = NULL;
 }
 
 int f2fs_register_sysfs(struct f2fs_sb_info *sbi)
@@ -325,6 +421,13 @@ int f2fs_register_sysfs(struct f2fs_sb_info *sbi)
 	struct super_block *sb = sbi->sb;
 	int err;
 
+	sbi->s_kobj.kset = &f2fs_kset;
+	init_completion(&sbi->s_kobj_unregister);
+	err = kobject_init_and_add(&sbi->s_kobj, &f2fs_sb_ktype, NULL,
+				"%s", sb->s_id);
+	if (err)
+		return err;
+
 	if (f2fs_proc_root)
 		sbi->s_proc = proc_mkdir(sb->s_id, f2fs_proc_root);
 
@@ -334,32 +437,15 @@ int f2fs_register_sysfs(struct f2fs_sb_info *sbi)
 		proc_create_data("segment_bits", S_IRUGO, sbi->s_proc,
 				 &f2fs_seq_segment_bits_fops, sb);
 	}
-
-	sbi->s_kobj.kset = f2fs_kset;
-	init_completion(&sbi->s_kobj_unregister);
-	err = kobject_init_and_add(&sbi->s_kobj, &f2fs_ktype, NULL,
-							"%s", sb->s_id);
-	if (err)
-		goto err_out;
 	return 0;
-err_out:
-	if (sbi->s_proc) {
-		remove_proc_entry("segment_info", sbi->s_proc);
-		remove_proc_entry("segment_bits", sbi->s_proc);
-		remove_proc_entry(sb->s_id, f2fs_proc_root);
-	}
-	return err;
 }
 
 void f2fs_unregister_sysfs(struct f2fs_sb_info *sbi)
 {
-	kobject_del(&sbi->s_kobj);
-	kobject_put(&sbi->s_kobj);
-	wait_for_completion(&sbi->s_kobj_unregister);
-
 	if (sbi->s_proc) {
 		remove_proc_entry("segment_info", sbi->s_proc);
 		remove_proc_entry("segment_bits", sbi->s_proc);
 		remove_proc_entry(sbi->sb->s_id, f2fs_proc_root);
 	}
+	kobject_del(&sbi->s_kobj);
 }
-- 
2.13.0.rc1.294.g07d810a77f-goog

Re: [f2fs-dev] [PATCH 1/2 v2] f2fs: expose /sys/fs/f2fs/features

[Chao Yu]

Hi Jaegeuk,

On 2017/7/27 5:44, Jaegeuk Kim wrote:
> Change log from v1:
>  - add /sys/fs/f2fs/dev/features
> 
> This patch exposes what features are supported by current f2fs build to sysfs
> entry via:
> 
> /sys/fs/f2fs/features/> /sys/fs/f2fs/dev/features
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/sysfs.c | 138 +++++++++++++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 112 insertions(+), 26 deletions(-)
> 
> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> index 5a78b9af92ef..83ab0dd73b2c 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -18,7 +18,6 @@
>  #include "gc.h"
>  
>  static struct proc_dir_entry *f2fs_proc_root;
> -static struct kset *f2fs_kset;
>  
>  /* Sysfs support for f2fs */
>  enum {
> @@ -41,6 +40,7 @@ struct f2fs_attr {
>  			 const char *, size_t);
>  	int struct_type;
>  	int offset;
> +	int id;
>  };
>  
>  static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int struct_type)
> @@ -76,6 +76,28 @@ static ssize_t lifetime_write_kbytes_show(struct f2fs_attr *a,
>  			BD_PART_WRITTEN(sbi)));
>  }
>  
> +static ssize_t features_show(struct f2fs_attr *a,
> +		struct f2fs_sb_info *sbi, char *buf)
> +{
> +	struct super_block *sb = sbi->sb;
> +	int len = 0;
> +
> +	if (!sb->s_bdev->bd_part)
> +		return snprintf(buf, PAGE_SIZE, "0\n");
> +
> +	if (f2fs_sb_has_crypto(sb))
> +		len += snprintf(buf, PAGE_SIZE - len, "%s\n", "encryption");

How about printing as below:
len += snprintf(buf, PAGE_SIZE - len, "%s\n", "encryption ");

It avoids unneeded ',' in the beginning of output string:
cat /sys/fs/f2fs/zram0/features
, extra_attr, projquota, inode_checksum

> +	if (f2fs_sb_mounted_blkzoned(sb))
> +		len += snprintf(buf, PAGE_SIZE - len, "%s\n", ", blkzoned");

len += snprintf(buf, PAGE_SIZE - len, "%s\n", "blkzoned ");

> +	if (f2fs_sb_has_extra_attr(sb))
> +		len += snprintf(buf, PAGE_SIZE - len, "%s\n", ", extra_attr");

ditto

> +	if (f2fs_sb_has_project_quota(sb))
> +		len += snprintf(buf, PAGE_SIZE - len, "%s\n", ", projquota");

ditto

> +	if (f2fs_sb_has_inode_chksum(sb))
> +		len += snprintf(buf, PAGE_SIZE - len, "%s\n", ", inode_checksum");

ditto

> +	return len;
> +}
> +
>  static ssize_t f2fs_sbi_show(struct f2fs_attr *a,
>  			struct f2fs_sb_info *sbi, char *buf)
>  {
> @@ -155,6 +177,24 @@ static void f2fs_sb_release(struct kobject *kobj)
>  	complete(&sbi->s_kobj_unregister);
>  }
>  
> +enum feat_id {
> +	FEAT_CRYPTO = 0,
> +	FEAT_BLKZONED,
> +	FEAT_ATOMIC_WRITE,

Adds below missing macro:
FEAT_EXTRA_ATTR,
FEAT_PROJECT_QUOTA,
FEAT_INODE_CHECKSUM,

> +};
> +
> +static ssize_t f2fs_feature_show(struct f2fs_attr *a,
> +		struct f2fs_sb_info *sbi, char *buf)
> +{
> +	switch (a->id) {
> +	case FEAT_CRYPTO:
> +	case FEAT_BLKZONED:
> +	case FEAT_ATOMIC_WRITE:

case FEAT_EXTRA_ATTR:
case FEAT_PROJECT_QUOTA:
case FEAT_INODE_CHECKSUM:

> +		return snprintf(buf, PAGE_SIZE, "supported\n");
> +	}
> +	return 0;
> +}
> +
>  #define F2FS_ATTR_OFFSET(_struct_type, _name, _mode, _show, _store, _offset) \
>  static struct f2fs_attr f2fs_attr_##_name = {			\
>  	.attr = {.name = __stringify(_name), .mode = _mode },	\
> @@ -172,6 +212,13 @@ static struct f2fs_attr f2fs_attr_##_name = {			\
>  #define F2FS_GENERAL_RO_ATTR(name) \
>  static struct f2fs_attr f2fs_attr_##name = __ATTR(name, 0444, name##_show, NULL)
>  
> +#define F2FS_FEATURE_RO_ATTR(_name, _id)			\
> +static struct f2fs_attr f2fs_attr_##_name = {			\
> +	.attr = {.name = __stringify(_name), .mode = 0444 },	\
> +	.show	= f2fs_feature_show,				\
> +	.id	= _id,						\
> +}
> +
>  F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_min_sleep_time, min_sleep_time);
>  F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_max_sleep_time, max_sleep_time);
>  F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time);
> @@ -196,6 +243,15 @@ F2FS_RW_ATTR(FAULT_INFO_RATE, f2fs_fault_info, inject_rate, inject_rate);
>  F2FS_RW_ATTR(FAULT_INFO_TYPE, f2fs_fault_info, inject_type, inject_type);
>  #endif
>  F2FS_GENERAL_RO_ATTR(lifetime_write_kbytes);
> +F2FS_GENERAL_RO_ATTR(features);
> +
> +#ifdef CONFIG_F2FS_FS_ENCRYPTION
> +F2FS_FEATURE_RO_ATTR(encryption, FEAT_CRYPTO);
> +#endif
> +#ifdef CONFIG_BLK_DEV_ZONED
> +F2FS_FEATURE_RO_ATTR(block_zoned, FEAT_BLKZONED);
> +#endif
> +F2FS_FEATURE_RO_ATTR(atomic_write, FEAT_ATOMIC_WRITE);

F2FS_FEATURE_RO_ATTR(extra_attr, FEAT_EXTRA_ATTR);
F2FS_FEATURE_RO_ATTR(project_quota, FEAT_PROJECT_QUOTA);
F2FS_FEATURE_RO_ATTR(inode_checksum, FEAT_INODE_CHECKSUM);

>  
>  #define ATTR_LIST(name) (&f2fs_attr_##name.attr)
>  static struct attribute *f2fs_attrs[] = {
> @@ -222,21 +278,50 @@ static struct attribute *f2fs_attrs[] = {
>  	ATTR_LIST(inject_type),
>  #endif
>  	ATTR_LIST(lifetime_write_kbytes),
> +	ATTR_LIST(features),
>  	ATTR_LIST(reserved_blocks),
>  	NULL,
>  };
>  
> +static struct attribute *f2fs_feat_attrs[] = {
> +#ifdef CONFIG_F2FS_FS_ENCRYPTION
> +	ATTR_LIST(encryption),
> +#endif
> +#ifdef CONFIG_BLK_DEV_ZONED
> +	ATTR_LIST(block_zoned),
> +#endif
> +	ATTR_LIST(atomic_write),

ATTR_LIST(extra_attr),
ATTR_LIST(project_quota),
ATTR_LIST(inode_checksum),

Thanks,

> +	NULL,
> +};
> +
>  static const struct sysfs_ops f2fs_attr_ops = {
>  	.show	= f2fs_attr_show,
>  	.store	= f2fs_attr_store,
>  };
>  
> -static struct kobj_type f2fs_ktype = {
> +static struct kobj_type f2fs_sb_ktype = {
>  	.default_attrs	= f2fs_attrs,
>  	.sysfs_ops	= &f2fs_attr_ops,
>  	.release	= f2fs_sb_release,
>  };
>  
> +static struct kobj_type f2fs_ktype = {
> +	.sysfs_ops	= &f2fs_attr_ops,
> +};
> +
> +static struct kset f2fs_kset = {
> +	.kobj   = {.ktype = &f2fs_ktype},
> +};
> +
> +static struct kobj_type f2fs_feat_ktype = {
> +	.default_attrs	= f2fs_feat_attrs,
> +	.sysfs_ops	= &f2fs_attr_ops,
> +};
> +
> +static struct kobject f2fs_feat = {
> +	.kset	= &f2fs_kset,
> +};
> +
>  static int segment_info_seq_show(struct seq_file *seq, void *offset)
>  {
>  	struct super_block *sb = seq->private;
> @@ -306,18 +391,29 @@ F2FS_PROC_FILE_DEF(segment_bits);
>  
>  int __init f2fs_init_sysfs(void)
>  {
> -	f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
> +	int ret;
>  
> -	f2fs_kset = kset_create_and_add("f2fs", NULL, fs_kobj);
> -	if (!f2fs_kset)
> -		return -ENOMEM;
> -	return 0;
> +	kobject_set_name(&f2fs_kset.kobj, "f2fs");
> +	f2fs_kset.kobj.parent = fs_kobj;
> +	ret = kset_register(&f2fs_kset);
> +	if (ret)
> +		return ret;
> +
> +	ret = kobject_init_and_add(&f2fs_feat, &f2fs_feat_ktype,
> +				   NULL, "features");
> +	if (ret)
> +		kset_unregister(&f2fs_kset);
> +	else
> +		f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
> +	return ret;
>  }
>  
>  void f2fs_exit_sysfs(void)
>  {
> -	kset_unregister(f2fs_kset);
> +	kobject_put(&f2fs_feat);
> +	kset_unregister(&f2fs_kset);
>  	remove_proc_entry("fs/f2fs", NULL);
> +	f2fs_proc_root = NULL;
>  }
>  
>  int f2fs_register_sysfs(struct f2fs_sb_info *sbi)
> @@ -325,6 +421,13 @@ int f2fs_register_sysfs(struct f2fs_sb_info *sbi)
>  	struct super_block *sb = sbi->sb;
>  	int err;
>  
> +	sbi->s_kobj.kset = &f2fs_kset;
> +	init_completion(&sbi->s_kobj_unregister);
> +	err = kobject_init_and_add(&sbi->s_kobj, &f2fs_sb_ktype, NULL,
> +				"%s", sb->s_id);
> +	if (err)
> +		return err;
> +
>  	if (f2fs_proc_root)
>  		sbi->s_proc = proc_mkdir(sb->s_id, f2fs_proc_root);
>  
> @@ -334,32 +437,15 @@ int f2fs_register_sysfs(struct f2fs_sb_info *sbi)
>  		proc_create_data("segment_bits", S_IRUGO, sbi->s_proc,
>  				 &f2fs_seq_segment_bits_fops, sb);
>  	}
> -
> -	sbi->s_kobj.kset = f2fs_kset;
> -	init_completion(&sbi->s_kobj_unregister);
> -	err = kobject_init_and_add(&sbi->s_kobj, &f2fs_ktype, NULL,
> -							"%s", sb->s_id);
> -	if (err)
> -		goto err_out;
>  	return 0;
> -err_out:
> -	if (sbi->s_proc) {
> -		remove_proc_entry("segment_info", sbi->s_proc);
> -		remove_proc_entry("segment_bits", sbi->s_proc);
> -		remove_proc_entry(sb->s_id, f2fs_proc_root);
> -	}
> -	return err;
>  }
>  
>  void f2fs_unregister_sysfs(struct f2fs_sb_info *sbi)
>  {
> -	kobject_del(&sbi->s_kobj);
> -	kobject_put(&sbi->s_kobj);
> -	wait_for_completion(&sbi->s_kobj_unregister);
> -
>  	if (sbi->s_proc) {
>  		remove_proc_entry("segment_info", sbi->s_proc);
>  		remove_proc_entry("segment_bits", sbi->s_proc);
>  		remove_proc_entry(sbi->sb->s_id, f2fs_proc_root);
>  	}
> +	kobject_del(&sbi->s_kobj);
>  }
> 

Re: [f2fs-dev] [PATCH 1/2 v3] f2fs: expose /sys/fs/f2fs/features

[Jaegeuk Kim]

 Change log from v2:
  - add missing new features
  - fix print out features

 Change log from v1:
  - add /sys/fs/f2fs/dev/features

>From cf512bfeed89d760138ade12014f17fc5779ca04 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Fri, 21 Jul 2017 17:14:09 -0700
Subject: [PATCH] f2fs: expose features to sysfs entry

This patch exposes what features are supported by current f2fs build to sysfs
entry via:

/sys/fs/f2fs/features/
/sys/fs/f2fs/dev/features

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/sysfs.c | 156 ++++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 130 insertions(+), 26 deletions(-)

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index ebb4ac76f070..1bc2cfb0b9df 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -18,7 +18,6 @@
 #include "gc.h"
 
 static struct proc_dir_entry *f2fs_proc_root;
-static struct kset *f2fs_kset;
 
 /* Sysfs support for f2fs */
 enum {
@@ -41,6 +40,7 @@ struct f2fs_attr {
 			 const char *, size_t);
 	int struct_type;
 	int offset;
+	int id;
 };
 
 static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int struct_type)
@@ -76,6 +76,34 @@ static ssize_t lifetime_write_kbytes_show(struct f2fs_attr *a,
 			BD_PART_WRITTEN(sbi)));
 }
 
+static ssize_t features_show(struct f2fs_attr *a,
+		struct f2fs_sb_info *sbi, char *buf)
+{
+	struct super_block *sb = sbi->sb;
+	int len = 0;
+
+	if (!sb->s_bdev->bd_part)
+		return snprintf(buf, PAGE_SIZE, "0\n");
+
+	if (f2fs_sb_has_crypto(sb))
+		len += snprintf(buf, PAGE_SIZE - len, "%s",
+						"encryption");
+	if (f2fs_sb_mounted_blkzoned(sb))
+		len += snprintf(buf + len, PAGE_SIZE - len, "%s%s",
+				len ? ", " : "", "blkzoned");
+	if (f2fs_sb_has_extra_attr(sb))
+		len += snprintf(buf + len, PAGE_SIZE - len, "%s%s",
+				len ? ", " : "", "extra_attr");
+	if (f2fs_sb_has_project_quota(sb))
+		len += snprintf(buf + len, PAGE_SIZE - len, "%s%s",
+				len ? ", " : "", "projquota");
+	if (f2fs_sb_has_inode_chksum(sb))
+		len += snprintf(buf + len, PAGE_SIZE - len, "%s%s",
+				len ? ", " : "", "inode_checksum");
+	len += snprintf(buf + len, PAGE_SIZE - len, "\n");
+	return len;
+}
+
 static ssize_t f2fs_sbi_show(struct f2fs_attr *a,
 			struct f2fs_sb_info *sbi, char *buf)
 {
@@ -155,6 +183,30 @@ static void f2fs_sb_release(struct kobject *kobj)
 	complete(&sbi->s_kobj_unregister);
 }
 
+enum feat_id {
+	FEAT_CRYPTO = 0,
+	FEAT_BLKZONED,
+	FEAT_ATOMIC_WRITE,
+	FEAT_EXTRA_ATTR,
+	FEAT_PROJECT_QUOTA,
+	FEAT_INODE_CHECKSUM,
+};
+
+static ssize_t f2fs_feature_show(struct f2fs_attr *a,
+		struct f2fs_sb_info *sbi, char *buf)
+{
+	switch (a->id) {
+	case FEAT_CRYPTO:
+	case FEAT_BLKZONED:
+	case FEAT_ATOMIC_WRITE:
+	case FEAT_EXTRA_ATTR:
+	case FEAT_PROJECT_QUOTA:
+	case FEAT_INODE_CHECKSUM:
+		return snprintf(buf, PAGE_SIZE, "supported\n");
+	}
+	return 0;
+}
+
 #define F2FS_ATTR_OFFSET(_struct_type, _name, _mode, _show, _store, _offset) \
 static struct f2fs_attr f2fs_attr_##_name = {			\
 	.attr = {.name = __stringify(_name), .mode = _mode },	\
@@ -172,6 +224,13 @@ static struct f2fs_attr f2fs_attr_##_name = {			\
 #define F2FS_GENERAL_RO_ATTR(name) \
 static struct f2fs_attr f2fs_attr_##name = __ATTR(name, 0444, name##_show, NULL)
 
+#define F2FS_FEATURE_RO_ATTR(_name, _id)			\
+static struct f2fs_attr f2fs_attr_##_name = {			\
+	.attr = {.name = __stringify(_name), .mode = 0444 },	\
+	.show	= f2fs_feature_show,				\
+	.id	= _id,						\
+}
+
 F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_min_sleep_time, min_sleep_time);
 F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_max_sleep_time, max_sleep_time);
 F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time);
@@ -197,6 +256,18 @@ F2FS_RW_ATTR(FAULT_INFO_RATE, f2fs_fault_info, inject_rate, inject_rate);
 F2FS_RW_ATTR(FAULT_INFO_TYPE, f2fs_fault_info, inject_type, inject_type);
 #endif
 F2FS_GENERAL_RO_ATTR(lifetime_write_kbytes);
+F2FS_GENERAL_RO_ATTR(features);
+
+#ifdef CONFIG_F2FS_FS_ENCRYPTION
+F2FS_FEATURE_RO_ATTR(encryption, FEAT_CRYPTO);
+#endif
+#ifdef CONFIG_BLK_DEV_ZONED
+F2FS_FEATURE_RO_ATTR(block_zoned, FEAT_BLKZONED);
+#endif
+F2FS_FEATURE_RO_ATTR(atomic_write, FEAT_ATOMIC_WRITE);
+F2FS_FEATURE_RO_ATTR(extra_attr, FEAT_EXTRA_ATTR);
+F2FS_FEATURE_RO_ATTR(project_quota, FEAT_PROJECT_QUOTA);
+F2FS_FEATURE_RO_ATTR(inode_checksum, FEAT_INODE_CHECKSUM);
 
 #define ATTR_LIST(name) (&f2fs_attr_##name.attr)
 static struct attribute *f2fs_attrs[] = {
@@ -224,21 +295,53 @@ static struct attribute *f2fs_attrs[] = {
 	ATTR_LIST(inject_type),
 #endif
 	ATTR_LIST(lifetime_write_kbytes),
+	ATTR_LIST(features),
 	ATTR_LIST(reserved_blocks),
 	NULL,
 };
 
+static struct attribute *f2fs_feat_attrs[] = {
+#ifdef CONFIG_F2FS_FS_ENCRYPTION
+	ATTR_LIST(encryption),
+#endif
+#ifdef CONFIG_BLK_DEV_ZONED
+	ATTR_LIST(block_zoned),
+#endif
+	ATTR_LIST(atomic_write),
+	ATTR_LIST(extra_attr),
+	ATTR_LIST(project_quota),
+	ATTR_LIST(inode_checksum),
+	NULL,
+};
+
 static const struct sysfs_ops f2fs_attr_ops = {
 	.show	= f2fs_attr_show,
 	.store	= f2fs_attr_store,
 };
 
-static struct kobj_type f2fs_ktype = {
+static struct kobj_type f2fs_sb_ktype = {
 	.default_attrs	= f2fs_attrs,
 	.sysfs_ops	= &f2fs_attr_ops,
 	.release	= f2fs_sb_release,
 };
 
+static struct kobj_type f2fs_ktype = {
+	.sysfs_ops	= &f2fs_attr_ops,
+};
+
+static struct kset f2fs_kset = {
+	.kobj   = {.ktype = &f2fs_ktype},
+};
+
+static struct kobj_type f2fs_feat_ktype = {
+	.default_attrs	= f2fs_feat_attrs,
+	.sysfs_ops	= &f2fs_attr_ops,
+};
+
+static struct kobject f2fs_feat = {
+	.kset	= &f2fs_kset,
+};
+
 static int segment_info_seq_show(struct seq_file *seq, void *offset)
 {
 	struct super_block *sb = seq->private;
@@ -308,18 +411,29 @@ F2FS_PROC_FILE_DEF(segment_bits);
 
 int __init f2fs_init_sysfs(void)
 {
-	f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
+	int ret;
 
-	f2fs_kset = kset_create_and_add("f2fs", NULL, fs_kobj);
-	if (!f2fs_kset)
-		return -ENOMEM;
-	return 0;
+	kobject_set_name(&f2fs_kset.kobj, "f2fs");
+	f2fs_kset.kobj.parent = fs_kobj;
+	ret = kset_register(&f2fs_kset);
+	if (ret)
+		return ret;
+
+	ret = kobject_init_and_add(&f2fs_feat, &f2fs_feat_ktype,
+				   NULL, "features");
+	if (ret)
+		kset_unregister(&f2fs_kset);
+	else
+		f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
+	return ret;
 }
 
 void f2fs_exit_sysfs(void)
 {
-	kset_unregister(f2fs_kset);
+	kobject_put(&f2fs_feat);
+	kset_unregister(&f2fs_kset);
 	remove_proc_entry("fs/f2fs", NULL);
+	f2fs_proc_root = NULL;
 }
 
 int f2fs_register_sysfs(struct f2fs_sb_info *sbi)
@@ -327,6 +441,13 @@ int f2fs_register_sysfs(struct f2fs_sb_info *sbi)
 	struct super_block *sb = sbi->sb;
 	int err;
 
+	sbi->s_kobj.kset = &f2fs_kset;
+	init_completion(&sbi->s_kobj_unregister);
+	err = kobject_init_and_add(&sbi->s_kobj, &f2fs_sb_ktype, NULL,
+				"%s", sb->s_id);
+	if (err)
+		return err;
+
 	if (f2fs_proc_root)
 		sbi->s_proc = proc_mkdir(sb->s_id, f2fs_proc_root);
 
@@ -336,32 +457,15 @@ int f2fs_register_sysfs(struct f2fs_sb_info *sbi)
 		proc_create_data("segment_bits", S_IRUGO, sbi->s_proc,
 				 &f2fs_seq_segment_bits_fops, sb);
 	}
-
-	sbi->s_kobj.kset = f2fs_kset;
-	init_completion(&sbi->s_kobj_unregister);
-	err = kobject_init_and_add(&sbi->s_kobj, &f2fs_ktype, NULL,
-							"%s", sb->s_id);
-	if (err)
-		goto err_out;
 	return 0;
-err_out:
-	if (sbi->s_proc) {
-		remove_proc_entry("segment_info", sbi->s_proc);
-		remove_proc_entry("segment_bits", sbi->s_proc);
-		remove_proc_entry(sb->s_id, f2fs_proc_root);
-	}
-	return err;
 }
 
 void f2fs_unregister_sysfs(struct f2fs_sb_info *sbi)
 {
-	kobject_del(&sbi->s_kobj);
-	kobject_put(&sbi->s_kobj);
-	wait_for_completion(&sbi->s_kobj_unregister);
-
 	if (sbi->s_proc) {
 		remove_proc_entry("segment_info", sbi->s_proc);
 		remove_proc_entry("segment_bits", sbi->s_proc);
 		remove_proc_entry(sbi->sb->s_id, f2fs_proc_root);
 	}
+	kobject_del(&sbi->s_kobj);
 }
-- 
2.13.0.rc1.294.g07d810a77f-goog

Re: [f2fs-dev] [PATCH 1/2 v3] f2fs: expose /sys/fs/f2fs/features

[Chao Yu]

On 2017/7/29 3:41, Jaegeuk Kim wrote:
>  Change log from v2:
>   - add missing new features
>   - fix print out features
> 
>  Change log from v1:
>   - add /sys/fs/f2fs/dev/features
> 
>>>From cf512bfeed89d760138ade12014f17fc5779ca04 Mon Sep 17 00:00:00 2001
> From: Jaegeuk Kim <jaegeuk@kernel.org>
> Date: Fri, 21 Jul 2017 17:14:09 -0700
> Subject: [PATCH] f2fs: expose features to sysfs entry
> 
> This patch exposes what features are supported by current f2fs build to sysfs
> entry via:
> 
> /sys/fs/f2fs/features/
> /sys/fs/f2fs/dev/features
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,