fs/erofs/sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C), 2008-2021, OPPO Mobile Comm Corp., Ltd.
   4  *             https://www.oppo.com/
   5  */
   6 #include <linux/sysfs.h>
   7 #include <linux/kobject.h>
   8
   9 #include "internal.h"
  10
  11 enum {
  12         attr_feature,
  13         attr_pointer_ui,
  14         attr_pointer_bool,
  15 };
  16
  17 enum {
  18         struct_erofs_sb_info,
  19         struct_erofs_mount_opts,
  20 };
  21
  22 struct erofs_attr {
  23         struct attribute attr;
  24         short attr_id;
  25         int struct_type, offset;
  26 };
  27
  28 #define EROFS_ATTR(_name, _mode, _id)                                   \
  29 static struct erofs_attr erofs_attr_##_name = {                         \
  30         .attr = {.name = __stringify(_name), .mode = _mode },           \
  31         .attr_id = attr_##_id,                                          \
  32 }
  33 #define EROFS_ATTR_FUNC(_name, _mode)   EROFS_ATTR(_name, _mode, _name)
  34 #define EROFS_ATTR_FEATURE(_name)       EROFS_ATTR(_name, 0444, feature)
  35
  36 #define EROFS_ATTR_OFFSET(_name, _mode, _id, _struct)   \
  37 static struct erofs_attr erofs_attr_##_name = {                 \
  38         .attr = {.name = __stringify(_name), .mode = _mode },   \
  39         .attr_id = attr_##_id,                                  \
  40         .struct_type = struct_##_struct,                        \
  41         .offset = offsetof(struct _struct, _name),\
  42 }
  43
  44 #define EROFS_ATTR_RW(_name, _id, _struct)      \
  45         EROFS_ATTR_OFFSET(_name, 0644, _id, _struct)
  46
  47 #define EROFS_RO_ATTR(_name, _id, _struct)      \
  48         EROFS_ATTR_OFFSET(_name, 0444, _id, _struct)
  49
  50 #define EROFS_ATTR_RW_UI(_name, _struct)        \
  51         EROFS_ATTR_RW(_name, pointer_ui, _struct)
  52
  53 #define EROFS_ATTR_RW_BOOL(_name, _struct)      \
  54         EROFS_ATTR_RW(_name, pointer_bool, _struct)
  55
  56 #define ATTR_LIST(name) (&erofs_attr_##name.attr)
  57
  58 #ifdef CONFIG_EROFS_FS_ZIP
  59 EROFS_ATTR_RW_UI(sync_decompress, erofs_mount_opts);
  60 #endif
  61
  62 static struct attribute *erofs_attrs[] = {
  63 #ifdef CONFIG_EROFS_FS_ZIP
  64         ATTR_LIST(sync_decompress),
  65 #endif
  66         NULL,
  67 };
  68 ATTRIBUTE_GROUPS(erofs);
  69
  70 /* Features this copy of erofs supports */
  71 EROFS_ATTR_FEATURE(zero_padding);
  72 EROFS_ATTR_FEATURE(compr_cfgs);
  73 EROFS_ATTR_FEATURE(big_pcluster);
  74 EROFS_ATTR_FEATURE(chunked_file);
  75 EROFS_ATTR_FEATURE(device_table);
  76 EROFS_ATTR_FEATURE(compr_head2);
  77 EROFS_ATTR_FEATURE(sb_chksum);
  78 EROFS_ATTR_FEATURE(ztailpacking);
  79
  80 static struct attribute *erofs_feat_attrs[] = {
  81         ATTR_LIST(zero_padding),
  82         ATTR_LIST(compr_cfgs),
  83         ATTR_LIST(big_pcluster),
  84         ATTR_LIST(chunked_file),
  85         ATTR_LIST(device_table),
  86         ATTR_LIST(compr_head2),
  87         ATTR_LIST(sb_chksum),
  88         ATTR_LIST(ztailpacking),
  89         NULL,
  90 };
  91 ATTRIBUTE_GROUPS(erofs_feat);
  92
  93 static unsigned char *__struct_ptr(struct erofs_sb_info *sbi,
  94                                           int struct_type, int offset)
  95 {
  96         if (struct_type == struct_erofs_sb_info)
  97                 return (unsigned char *)sbi + offset;
  98         if (struct_type == struct_erofs_mount_opts)
  99                 return (unsigned char *)&sbi->opt + offset;
 100         return NULL;
 101 }
 102
 103 static ssize_t erofs_attr_show(struct kobject *kobj,
 104                                 struct attribute *attr, char *buf)
 105 {
 106         struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
 107                                                 s_kobj);
 108         struct erofs_attr *a = container_of(attr, struct erofs_attr, attr);
 109         unsigned char *ptr = __struct_ptr(sbi, a->struct_type, a->offset);
 110
 111         switch (a->attr_id) {
 112         case attr_feature:
 113                 return sysfs_emit(buf, "supported\n");
 114         case attr_pointer_ui:
 115                 if (!ptr)
 116                         return 0;
 117                 return sysfs_emit(buf, "%u\n", *(unsigned int *)ptr);
 118         case attr_pointer_bool:
 119                 if (!ptr)
 120                         return 0;
 121                 return sysfs_emit(buf, "%d\n", *(bool *)ptr);
 122         }
 123         return 0;
 124 }
 125
 126 static ssize_t erofs_attr_store(struct kobject *kobj, struct attribute *attr,
 127                                                 const char *buf, size_t len)
 128 {
 129         struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
 130                                                 s_kobj);
 131         struct erofs_attr *a = container_of(attr, struct erofs_attr, attr);
 132         unsigned char *ptr = __struct_ptr(sbi, a->struct_type, a->offset);
 133         unsigned long t;
 134         int ret;
 135
 136         switch (a->attr_id) {
 137         case attr_pointer_ui:
 138                 if (!ptr)
 139                         return 0;
 140                 ret = kstrtoul(skip_spaces(buf), 0, &t);
 141                 if (ret)
 142                         return ret;
 143                 if (t != (unsigned int)t)
 144                         return -ERANGE;
 145 #ifdef CONFIG_EROFS_FS_ZIP
 146                 if (!strcmp(a->attr.name, "sync_decompress") &&
 147                     (t > EROFS_SYNC_DECOMPRESS_FORCE_OFF))
 148                         return -EINVAL;
 149 #endif
 150                 *(unsigned int *)ptr = t;
 151                 return len;
 152         case attr_pointer_bool:
 153                 if (!ptr)
 154                         return 0;
 155                 ret = kstrtoul(skip_spaces(buf), 0, &t);
 156                 if (ret)
 157                         return ret;
 158                 if (t != 0 && t != 1)
 159                         return -EINVAL;
 160                 *(bool *)ptr = !!t;
 161                 return len;
 162         }
 163         return 0;
 164 }
 165
 166 static void erofs_sb_release(struct kobject *kobj)
 167 {
 168         struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
 169                                                  s_kobj);
 170         complete(&sbi->s_kobj_unregister);
 171 }
 172
 173 static const struct sysfs_ops erofs_attr_ops = {
 174         .show   = erofs_attr_show,
 175         .store  = erofs_attr_store,
 176 };
 177
 178 static struct kobj_type erofs_sb_ktype = {
 179         .default_groups = erofs_groups,
 180         .sysfs_ops      = &erofs_attr_ops,
 181         .release        = erofs_sb_release,
 182 };
 183
 184 static struct kobj_type erofs_ktype = {
 185         .sysfs_ops      = &erofs_attr_ops,
 186 };
 187
 188 static struct kset erofs_root = {
 189         .kobj   = {.ktype = &erofs_ktype},
 190 };
 191
 192 static struct kobj_type erofs_feat_ktype = {
 193         .default_groups = erofs_feat_groups,
 194         .sysfs_ops      = &erofs_attr_ops,
 195 };
 196
 197 static struct kobject erofs_feat = {
 198         .kset   = &erofs_root,
 199 };
 200
 201 int erofs_register_sysfs(struct super_block *sb)
 202 {
 203         struct erofs_sb_info *sbi = EROFS_SB(sb);
 204         int err;
 205
 206         sbi->s_kobj.kset = &erofs_root;
 207         init_completion(&sbi->s_kobj_unregister);
 208         err = kobject_init_and_add(&sbi->s_kobj, &erofs_sb_ktype, NULL, "%s",
 209                         erofs_is_fscache_mode(sb) ? sbi->opt.fsid : sb->s_id);
 210         if (err)
 211                 goto put_sb_kobj;
 212         return 0;
 213
 214 put_sb_kobj:
 215         kobject_put(&sbi->s_kobj);
 216         wait_for_completion(&sbi->s_kobj_unregister);
 217         return err;
 218 }
 219
 220 void erofs_unregister_sysfs(struct super_block *sb)
 221 {
 222         struct erofs_sb_info *sbi = EROFS_SB(sb);
 223
 224         if (sbi->s_kobj.state_in_sysfs) {
 225                 kobject_del(&sbi->s_kobj);
 226                 kobject_put(&sbi->s_kobj);
 227                 wait_for_completion(&sbi->s_kobj_unregister);
 228         }
 229 }
 230
 231 int __init erofs_init_sysfs(void)
 232 {
 233         int ret;
 234
 235         kobject_set_name(&erofs_root.kobj, "erofs");
 236         erofs_root.kobj.parent = fs_kobj;
 237         ret = kset_register(&erofs_root);
 238         if (ret)
 239                 goto root_err;
 240
 241         ret = kobject_init_and_add(&erofs_feat, &erofs_feat_ktype,
 242                                    NULL, "features");
 243         if (ret)
 244                 goto feat_err;
 245         return ret;
 246
 247 feat_err:
 248         kobject_put(&erofs_feat);
 249         kset_unregister(&erofs_root);
 250 root_err:
 251         return ret;
 252 }
 253
 254 void erofs_exit_sysfs(void)
 255 {
 256         kobject_put(&erofs_feat);
 257         kset_unregister(&erofs_root);
 258 }