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

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 5a78b9a..1e31d0c 100644 (file)
--- 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);
@@ -196,6 +255,18 @@ 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[] = {
@@ -222,21 +293,53 @@ 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;
@@ -306,18 +409,29 @@ 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 +439,13 @@ 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 +455,15 @@ 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);
 }