fs/ext4/sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/ext4/sysfs.c
   4  *
   5  * Copyright (C) 1992, 1993, 1994, 1995
   6  * Remy Card ([email protected])
   7  * Theodore Ts'o ([email protected])
   8  *
   9  */
  10
  11 #include <linux/time.h>
  12 #include <linux/fs.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/slab.h>
  15 #include <linux/proc_fs.h>
  16
  17 #include "ext4.h"
  18 #include "ext4_jbd2.h"
  19
  20 typedef enum {
  21         attr_noop,
  22         attr_delayed_allocation_blocks,
  23         attr_session_write_kbytes,
  24         attr_lifetime_write_kbytes,
  25         attr_reserved_clusters,
  26         attr_inode_readahead,
  27         attr_trigger_test_error,
  28         attr_feature,
  29         attr_pointer_ui,
  30         attr_pointer_atomic,
  31 } attr_id_t;
  32
  33 typedef enum {
  34         ptr_explicit,
  35         ptr_ext4_sb_info_offset,
  36         ptr_ext4_super_block_offset,
  37 } attr_ptr_t;
  38
  39 static const char proc_dirname[] = "fs/ext4";
  40 static struct proc_dir_entry *ext4_proc_root;
  41
  42 struct ext4_attr {
  43         struct attribute attr;
  44         short attr_id;
  45         short attr_ptr;
  46         union {
  47                 int offset;
  48                 void *explicit_ptr;
  49         } u;
  50 };
  51
  52 static ssize_t session_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
  53 {
  54         struct super_block *sb = sbi->s_buddy_cache->i_sb;
  55
  56         if (!sb->s_bdev->bd_part)
  57                 return snprintf(buf, PAGE_SIZE, "0\n");
  58         return snprintf(buf, PAGE_SIZE, "%lu\n",
  59                         (part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
  60                          sbi->s_sectors_written_start) >> 1);
  61 }
  62
  63 static ssize_t lifetime_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
  64 {
  65         struct super_block *sb = sbi->s_buddy_cache->i_sb;
  66
  67         if (!sb->s_bdev->bd_part)
  68                 return snprintf(buf, PAGE_SIZE, "0\n");
  69         return snprintf(buf, PAGE_SIZE, "%llu\n",
  70                         (unsigned long long)(sbi->s_kbytes_written +
  71                         ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
  72                           EXT4_SB(sb)->s_sectors_written_start) >> 1)));
  73 }
  74
  75 static ssize_t inode_readahead_blks_store(struct ext4_sb_info *sbi,
  76                                           const char *buf, size_t count)
  77 {
  78         unsigned long t;
  79         int ret;
  80
  81         ret = kstrtoul(skip_spaces(buf), 0, &t);
  82         if (ret)
  83                 return ret;
  84
  85         if (t && (!is_power_of_2(t) || t > 0x40000000))
  86                 return -EINVAL;
  87
  88         sbi->s_inode_readahead_blks = t;
  89         return count;
  90 }
  91
  92 static ssize_t reserved_clusters_store(struct ext4_sb_info *sbi,
  93                                    const char *buf, size_t count)
  94 {
  95         unsigned long long val;
  96         ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
  97                                  sbi->s_cluster_bits);
  98         int ret;
  99
 100         ret = kstrtoull(skip_spaces(buf), 0, &val);
 101         if (ret || val >= clusters)
 102                 return -EINVAL;
 103
 104         atomic64_set(&sbi->s_resv_clusters, val);
 105         return count;
 106 }
 107
 108 static ssize_t trigger_test_error(struct ext4_sb_info *sbi,
 109                                   const char *buf, size_t count)
 110 {
 111         int len = count;
 112
 113         if (!capable(CAP_SYS_ADMIN))
 114                 return -EPERM;
 115
 116         if (len && buf[len-1] == '\n')
 117                 len--;
 118
 119         if (len)
 120                 ext4_error(sbi->s_sb, "%.*s", len, buf);
 121         return count;
 122 }
 123
 124 #define EXT4_ATTR(_name,_mode,_id)                                      \
 125 static struct ext4_attr ext4_attr_##_name = {                           \
 126         .attr = {.name = __stringify(_name), .mode = _mode },           \
 127         .attr_id = attr_##_id,                                          \
 128 }
 129
 130 #define EXT4_ATTR_FUNC(_name,_mode)  EXT4_ATTR(_name,_mode,_name)
 131
 132 #define EXT4_ATTR_FEATURE(_name)   EXT4_ATTR(_name, 0444, feature)
 133
 134 #define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname)       \
 135 static struct ext4_attr ext4_attr_##_name = {                   \
 136         .attr = {.name = __stringify(_name), .mode = _mode },   \
 137         .attr_id = attr_##_id,                                  \
 138         .attr_ptr = ptr_##_struct##_offset,                     \
 139         .u = {                                                  \
 140                 .offset = offsetof(struct _struct, _elname),\
 141         },                                                      \
 142 }
 143
 144 #define EXT4_RO_ATTR_ES_UI(_name,_elname)                               \
 145         EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)
 146
 147 #define EXT4_RW_ATTR_SBI_UI(_name,_elname)      \
 148         EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
 149
 150 #define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
 151 static struct ext4_attr ext4_attr_##_name = {                   \
 152         .attr = {.name = __stringify(_name), .mode = _mode },   \
 153         .attr_id = attr_##_id,                                  \
 154         .attr_ptr = ptr_explicit,                               \
 155         .u = {                                                  \
 156                 .explicit_ptr = _ptr,                           \
 157         },                                                      \
 158 }
 159
 160 #define ATTR_LIST(name) &ext4_attr_##name.attr
 161
 162 EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
 163 EXT4_ATTR_FUNC(session_write_kbytes, 0444);
 164 EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
 165 EXT4_ATTR_FUNC(reserved_clusters, 0644);
 166
 167 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
 168                  ext4_sb_info, s_inode_readahead_blks);
 169 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
 170 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
 171 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
 172 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
 173 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
 174 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
 175 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
 176 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
 177 EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
 178 EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
 179 EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
 180 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
 181 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
 182 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
 183 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
 184 EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
 185 EXT4_RO_ATTR_ES_UI(first_error_time, s_first_error_time);
 186 EXT4_RO_ATTR_ES_UI(last_error_time, s_last_error_time);
 187
 188 static unsigned int old_bump_val = 128;
 189 EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
 190
 191 static struct attribute *ext4_attrs[] = {
 192         ATTR_LIST(delayed_allocation_blocks),
 193         ATTR_LIST(session_write_kbytes),
 194         ATTR_LIST(lifetime_write_kbytes),
 195         ATTR_LIST(reserved_clusters),
 196         ATTR_LIST(inode_readahead_blks),
 197         ATTR_LIST(inode_goal),
 198         ATTR_LIST(mb_stats),
 199         ATTR_LIST(mb_max_to_scan),
 200         ATTR_LIST(mb_min_to_scan),
 201         ATTR_LIST(mb_order2_req),
 202         ATTR_LIST(mb_stream_req),
 203         ATTR_LIST(mb_group_prealloc),
 204         ATTR_LIST(max_writeback_mb_bump),
 205         ATTR_LIST(extent_max_zeroout_kb),
 206         ATTR_LIST(trigger_fs_error),
 207         ATTR_LIST(err_ratelimit_interval_ms),
 208         ATTR_LIST(err_ratelimit_burst),
 209         ATTR_LIST(warning_ratelimit_interval_ms),
 210         ATTR_LIST(warning_ratelimit_burst),
 211         ATTR_LIST(msg_ratelimit_interval_ms),
 212         ATTR_LIST(msg_ratelimit_burst),
 213         ATTR_LIST(errors_count),
 214         ATTR_LIST(first_error_time),
 215         ATTR_LIST(last_error_time),
 216         NULL,
 217 };
 218
 219 /* Features this copy of ext4 supports */
 220 EXT4_ATTR_FEATURE(lazy_itable_init);
 221 EXT4_ATTR_FEATURE(batched_discard);
 222 EXT4_ATTR_FEATURE(meta_bg_resize);
 223 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 224 EXT4_ATTR_FEATURE(encryption);
 225 #endif
 226 EXT4_ATTR_FEATURE(metadata_csum_seed);
 227
 228 static struct attribute *ext4_feat_attrs[] = {
 229         ATTR_LIST(lazy_itable_init),
 230         ATTR_LIST(batched_discard),
 231         ATTR_LIST(meta_bg_resize),
 232 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 233         ATTR_LIST(encryption),
 234 #endif
 235         ATTR_LIST(metadata_csum_seed),
 236         NULL,
 237 };
 238
 239 static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
 240 {
 241         switch (a->attr_ptr) {
 242         case ptr_explicit:
 243                 return a->u.explicit_ptr;
 244         case ptr_ext4_sb_info_offset:
 245                 return (void *) (((char *) sbi) + a->u.offset);
 246         case ptr_ext4_super_block_offset:
 247                 return (void *) (((char *) sbi->s_es) + a->u.offset);
 248         }
 249         return NULL;
 250 }
 251
 252 static ssize_t ext4_attr_show(struct kobject *kobj,
 253                               struct attribute *attr, char *buf)
 254 {
 255         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 256                                                 s_kobj);
 257         struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 258         void *ptr = calc_ptr(a, sbi);
 259
 260         switch (a->attr_id) {
 261         case attr_delayed_allocation_blocks:
 262                 return snprintf(buf, PAGE_SIZE, "%llu\n",
 263                                 (s64) EXT4_C2B(sbi,
 264                        percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
 265         case attr_session_write_kbytes:
 266                 return session_write_kbytes_show(sbi, buf);
 267         case attr_lifetime_write_kbytes:
 268                 return lifetime_write_kbytes_show(sbi, buf);
 269         case attr_reserved_clusters:
 270                 return snprintf(buf, PAGE_SIZE, "%llu\n",
 271                                 (unsigned long long)
 272                                 atomic64_read(&sbi->s_resv_clusters));
 273         case attr_inode_readahead:
 274         case attr_pointer_ui:
 275                 if (!ptr)
 276                         return 0;
 277                 return snprintf(buf, PAGE_SIZE, "%u\n",
 278                                 *((unsigned int *) ptr));
 279         case attr_pointer_atomic:
 280                 if (!ptr)
 281                         return 0;
 282                 return snprintf(buf, PAGE_SIZE, "%d\n",
 283                                 atomic_read((atomic_t *) ptr));
 284         case attr_feature:
 285                 return snprintf(buf, PAGE_SIZE, "supported\n");
 286         }
 287
 288         return 0;
 289 }
 290
 291 static ssize_t ext4_attr_store(struct kobject *kobj,
 292                                struct attribute *attr,
 293                                const char *buf, size_t len)
 294 {
 295         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 296                                                 s_kobj);
 297         struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 298         void *ptr = calc_ptr(a, sbi);
 299         unsigned long t;
 300         int ret;
 301
 302         switch (a->attr_id) {
 303         case attr_reserved_clusters:
 304                 return reserved_clusters_store(sbi, buf, len);
 305         case attr_pointer_ui:
 306                 if (!ptr)
 307                         return 0;
 308                 ret = kstrtoul(skip_spaces(buf), 0, &t);
 309                 if (ret)
 310                         return ret;
 311                 *((unsigned int *) ptr) = t;
 312                 return len;
 313         case attr_inode_readahead:
 314                 return inode_readahead_blks_store(sbi, buf, len);
 315         case attr_trigger_test_error:
 316                 return trigger_test_error(sbi, buf, len);
 317         }
 318         return 0;
 319 }
 320
 321 static void ext4_sb_release(struct kobject *kobj)
 322 {
 323         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 324                                                 s_kobj);
 325         complete(&sbi->s_kobj_unregister);
 326 }
 327
 328 static const struct sysfs_ops ext4_attr_ops = {
 329         .show   = ext4_attr_show,
 330         .store  = ext4_attr_store,
 331 };
 332
 333 static struct kobj_type ext4_sb_ktype = {
 334         .default_attrs  = ext4_attrs,
 335         .sysfs_ops      = &ext4_attr_ops,
 336         .release        = ext4_sb_release,
 337 };
 338
 339 static struct kobj_type ext4_feat_ktype = {
 340         .default_attrs  = ext4_feat_attrs,
 341         .sysfs_ops      = &ext4_attr_ops,
 342         .release        = (void (*)(struct kobject *))kfree,
 343 };
 344
 345 static struct kobject *ext4_root;
 346
 347 static struct kobject *ext4_feat;
 348
 349 #define PROC_FILE_SHOW_DEFN(name) \
 350 static int name##_open(struct inode *inode, struct file *file) \
 351 { \
 352         return single_open(file, ext4_seq_##name##_show, PDE_DATA(inode)); \
 353 } \
 354 \
 355 static const struct file_operations ext4_seq_##name##_fops = { \
 356         .open           = name##_open, \
 357         .read           = seq_read, \
 358         .llseek         = seq_lseek, \
 359         .release        = single_release, \
 360 }
 361
 362 #define PROC_FILE_LIST(name) \
 363         { __stringify(name), &ext4_seq_##name##_fops }
 364
 365 PROC_FILE_SHOW_DEFN(es_shrinker_info);
 366 PROC_FILE_SHOW_DEFN(options);
 367
 368 static const struct ext4_proc_files {
 369         const char *name;
 370         const struct file_operations *fops;
 371 } proc_files[] = {
 372         PROC_FILE_LIST(options),
 373         PROC_FILE_LIST(es_shrinker_info),
 374         PROC_FILE_LIST(mb_groups),
 375         { NULL, NULL },
 376 };
 377
 378 int ext4_register_sysfs(struct super_block *sb)
 379 {
 380         struct ext4_sb_info *sbi = EXT4_SB(sb);
 381         const struct ext4_proc_files *p;
 382         int err;
 383
 384         init_completion(&sbi->s_kobj_unregister);
 385         err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, ext4_root,
 386                                    "%s", sb->s_id);
 387         if (err) {
 388                 kobject_put(&sbi->s_kobj);
 389                 wait_for_completion(&sbi->s_kobj_unregister);
 390                 return err;
 391         }
 392
 393         if (ext4_proc_root)
 394                 sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
 395
 396         if (sbi->s_proc) {
 397                 for (p = proc_files; p->name; p++)
 398                         proc_create_data(p->name, S_IRUGO, sbi->s_proc,
 399                                          p->fops, sb);
 400         }
 401         return 0;
 402 }
 403
 404 void ext4_unregister_sysfs(struct super_block *sb)
 405 {
 406         struct ext4_sb_info *sbi = EXT4_SB(sb);
 407         const struct ext4_proc_files *p;
 408
 409         if (sbi->s_proc) {
 410                 for (p = proc_files; p->name; p++)
 411                         remove_proc_entry(p->name, sbi->s_proc);
 412                 remove_proc_entry(sb->s_id, ext4_proc_root);
 413         }
 414         kobject_del(&sbi->s_kobj);
 415 }
 416
 417 int __init ext4_init_sysfs(void)
 418 {
 419         int ret;
 420
 421         ext4_root = kobject_create_and_add("ext4", fs_kobj);
 422         if (!ext4_root)
 423                 return -ENOMEM;
 424
 425         ext4_feat = kzalloc(sizeof(*ext4_feat), GFP_KERNEL);
 426         if (!ext4_feat) {
 427                 ret = -ENOMEM;
 428                 goto root_err;
 429         }
 430
 431         ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype,
 432                                    ext4_root, "features");
 433         if (ret)
 434                 goto feat_err;
 435
 436         ext4_proc_root = proc_mkdir(proc_dirname, NULL);
 437         return ret;
 438
 439 feat_err:
 440         kobject_put(ext4_feat);
 441         ext4_feat = NULL;
 442 root_err:
 443         kobject_put(ext4_root);
 444         ext4_root = NULL;
 445         return ret;
 446 }
 447
 448 void ext4_exit_sysfs(void)
 449 {
 450         kobject_put(ext4_feat);
 451         ext4_feat = NULL;
 452         kobject_put(ext4_root);
 453         ext4_root = NULL;
 454         remove_proc_entry(proc_dirname, NULL);
 455         ext4_proc_root = NULL;
 456 }
 457