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 (card@masi.ibp.fr)
   7  * Theodore Ts'o (tytso@mit.edu)
   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_sra_exceeded_retry_limit,
  27         attr_inode_readahead,
  28         attr_trigger_test_error,
  29         attr_first_error_time,
  30         attr_last_error_time,
  31         attr_feature,
  32         attr_pointer_ui,
  33         attr_pointer_atomic,
  34         attr_journal_task,
  35 } attr_id_t;
  36
  37 typedef enum {
  38         ptr_explicit,
  39         ptr_ext4_sb_info_offset,
  40         ptr_ext4_super_block_offset,
  41 } attr_ptr_t;
  42
  43 static const char proc_dirname[] = "fs/ext4";
  44 static struct proc_dir_entry *ext4_proc_root;
  45
  46 struct ext4_attr {
  47         struct attribute attr;
  48         short attr_id;
  49         short attr_ptr;
  50         union {
  51                 int offset;
  52                 void *explicit_ptr;
  53         } u;
  54 };
  55
  56 static ssize_t session_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
  57 {
  58         struct super_block *sb = sbi->s_buddy_cache->i_sb;
  59
  60         if (!sb->s_bdev->bd_part)
  61                 return snprintf(buf, PAGE_SIZE, "0\n");
  62         return snprintf(buf, PAGE_SIZE, "%lu\n",
  63                         (part_stat_read(sb->s_bdev->bd_part,
  64                                         sectors[STAT_WRITE]) -
  65                          sbi->s_sectors_written_start) >> 1);
  66 }
  67
  68 static ssize_t lifetime_write_kbytes_show(struct ext4_sb_info *sbi, char *buf)
  69 {
  70         struct super_block *sb = sbi->s_buddy_cache->i_sb;
  71
  72         if (!sb->s_bdev->bd_part)
  73                 return snprintf(buf, PAGE_SIZE, "0\n");
  74         return snprintf(buf, PAGE_SIZE, "%llu\n",
  75                         (unsigned long long)(sbi->s_kbytes_written +
  76                         ((part_stat_read(sb->s_bdev->bd_part,
  77                                          sectors[STAT_WRITE]) -
  78                           EXT4_SB(sb)->s_sectors_written_start) >> 1)));
  79 }
  80
  81 static ssize_t inode_readahead_blks_store(struct ext4_sb_info *sbi,
  82                                           const char *buf, size_t count)
  83 {
  84         unsigned long t;
  85         int ret;
  86
  87         ret = kstrtoul(skip_spaces(buf), 0, &t);
  88         if (ret)
  89                 return ret;
  90
  91         if (t && (!is_power_of_2(t) || t > 0x40000000))
  92                 return -EINVAL;
  93
  94         sbi->s_inode_readahead_blks = t;
  95         return count;
  96 }
  97
  98 static ssize_t reserved_clusters_store(struct ext4_sb_info *sbi,
  99                                    const char *buf, size_t count)
 100 {
 101         unsigned long long val;
 102         ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
 103                                  sbi->s_cluster_bits);
 104         int ret;
 105
 106         ret = kstrtoull(skip_spaces(buf), 0, &val);
 107         if (ret || val >= clusters)
 108                 return -EINVAL;
 109
 110         atomic64_set(&sbi->s_resv_clusters, val);
 111         return count;
 112 }
 113
 114 static ssize_t trigger_test_error(struct ext4_sb_info *sbi,
 115                                   const char *buf, size_t count)
 116 {
 117         int len = count;
 118
 119         if (!capable(CAP_SYS_ADMIN))
 120                 return -EPERM;
 121
 122         if (len && buf[len-1] == '\n')
 123                 len--;
 124
 125         if (len)
 126                 ext4_error(sbi->s_sb, "%.*s", len, buf);
 127         return count;
 128 }
 129
 130 static ssize_t journal_task_show(struct ext4_sb_info *sbi, char *buf)
 131 {
 132         if (!sbi->s_journal)
 133                 return snprintf(buf, PAGE_SIZE, "<none>\n");
 134         return snprintf(buf, PAGE_SIZE, "%d\n",
 135                         task_pid_vnr(sbi->s_journal->j_task));
 136 }
 137
 138 #define EXT4_ATTR(_name,_mode,_id)                                      \
 139 static struct ext4_attr ext4_attr_##_name = {                           \
 140         .attr = {.name = __stringify(_name), .mode = _mode },           \
 141         .attr_id = attr_##_id,                                          \
 142 }
 143
 144 #define EXT4_ATTR_FUNC(_name,_mode)  EXT4_ATTR(_name,_mode,_name)
 145
 146 #define EXT4_ATTR_FEATURE(_name)   EXT4_ATTR(_name, 0444, feature)
 147
 148 #define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname)       \
 149 static struct ext4_attr ext4_attr_##_name = {                   \
 150         .attr = {.name = __stringify(_name), .mode = _mode },   \
 151         .attr_id = attr_##_id,                                  \
 152         .attr_ptr = ptr_##_struct##_offset,                     \
 153         .u = {                                                  \
 154                 .offset = offsetof(struct _struct, _elname),\
 155         },                                                      \
 156 }
 157
 158 #define EXT4_RO_ATTR_ES_UI(_name,_elname)                               \
 159         EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)
 160
 161 #define EXT4_RW_ATTR_SBI_UI(_name,_elname)      \
 162         EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
 163
 164 #define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
 165 static struct ext4_attr ext4_attr_##_name = {                   \
 166         .attr = {.name = __stringify(_name), .mode = _mode },   \
 167         .attr_id = attr_##_id,                                  \
 168         .attr_ptr = ptr_explicit,                               \
 169         .u = {                                                  \
 170                 .explicit_ptr = _ptr,                           \
 171         },                                                      \
 172 }
 173
 174 #define ATTR_LIST(name) &ext4_attr_##name.attr
 175
 176 EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
 177 EXT4_ATTR_FUNC(session_write_kbytes, 0444);
 178 EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
 179 EXT4_ATTR_FUNC(reserved_clusters, 0644);
 180 EXT4_ATTR_FUNC(sra_exceeded_retry_limit, 0444);
 181
 182 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
 183                  ext4_sb_info, s_inode_readahead_blks);
 184 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
 185 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
 186 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
 187 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
 188 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
 189 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
 190 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
 191 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
 192 EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
 193 EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
 194 EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
 195 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
 196 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
 197 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
 198 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
 199 EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
 200 EXT4_ATTR(first_error_time, 0444, first_error_time);
 201 EXT4_ATTR(last_error_time, 0444, last_error_time);
 202 EXT4_ATTR(journal_task, 0444, journal_task);
 203
 204 static unsigned int old_bump_val = 128;
 205 EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
 206
 207 static struct attribute *ext4_attrs[] = {
 208         ATTR_LIST(delayed_allocation_blocks),
 209         ATTR_LIST(session_write_kbytes),
 210         ATTR_LIST(lifetime_write_kbytes),
 211         ATTR_LIST(reserved_clusters),
 212         ATTR_LIST(sra_exceeded_retry_limit),
 213         ATTR_LIST(inode_readahead_blks),
 214         ATTR_LIST(inode_goal),
 215         ATTR_LIST(mb_stats),
 216         ATTR_LIST(mb_max_to_scan),
 217         ATTR_LIST(mb_min_to_scan),
 218         ATTR_LIST(mb_order2_req),
 219         ATTR_LIST(mb_stream_req),
 220         ATTR_LIST(mb_group_prealloc),
 221         ATTR_LIST(max_writeback_mb_bump),
 222         ATTR_LIST(extent_max_zeroout_kb),
 223         ATTR_LIST(trigger_fs_error),
 224         ATTR_LIST(err_ratelimit_interval_ms),
 225         ATTR_LIST(err_ratelimit_burst),
 226         ATTR_LIST(warning_ratelimit_interval_ms),
 227         ATTR_LIST(warning_ratelimit_burst),
 228         ATTR_LIST(msg_ratelimit_interval_ms),
 229         ATTR_LIST(msg_ratelimit_burst),
 230         ATTR_LIST(errors_count),
 231         ATTR_LIST(first_error_time),
 232         ATTR_LIST(last_error_time),
 233         ATTR_LIST(journal_task),
 234         NULL,
 235 };
 236 ATTRIBUTE_GROUPS(ext4);
 237
 238 /* Features this copy of ext4 supports */
 239 EXT4_ATTR_FEATURE(lazy_itable_init);
 240 EXT4_ATTR_FEATURE(batched_discard);
 241 EXT4_ATTR_FEATURE(meta_bg_resize);
 242 #ifdef CONFIG_FS_ENCRYPTION
 243 EXT4_ATTR_FEATURE(encryption);
 244 #endif
 245 #ifdef CONFIG_UNICODE
 246 EXT4_ATTR_FEATURE(casefold);
 247 #endif
 248 #ifdef CONFIG_FS_VERITY
 249 EXT4_ATTR_FEATURE(verity);
 250 #endif
 251 EXT4_ATTR_FEATURE(metadata_csum_seed);
 252
 253 static struct attribute *ext4_feat_attrs[] = {
 254         ATTR_LIST(lazy_itable_init),
 255         ATTR_LIST(batched_discard),
 256         ATTR_LIST(meta_bg_resize),
 257 #ifdef CONFIG_FS_ENCRYPTION
 258         ATTR_LIST(encryption),
 259 #endif
 260 #ifdef CONFIG_UNICODE
 261         ATTR_LIST(casefold),
 262 #endif
 263 #ifdef CONFIG_FS_VERITY
 264         ATTR_LIST(verity),
 265 #endif
 266         ATTR_LIST(metadata_csum_seed),
 267         NULL,
 268 };
 269 ATTRIBUTE_GROUPS(ext4_feat);
 270
 271 static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
 272 {
 273         switch (a->attr_ptr) {
 274         case ptr_explicit:
 275                 return a->u.explicit_ptr;
 276         case ptr_ext4_sb_info_offset:
 277                 return (void *) (((char *) sbi) + a->u.offset);
 278         case ptr_ext4_super_block_offset:
 279                 return (void *) (((char *) sbi->s_es) + a->u.offset);
 280         }
 281         return NULL;
 282 }
 283
 284 static ssize_t __print_tstamp(char *buf, __le32 lo, __u8 hi)
 285 {
 286         return snprintf(buf, PAGE_SIZE, "%lld",
 287                         ((time64_t)hi << 32) + le32_to_cpu(lo));
 288 }
 289
 290 #define print_tstamp(buf, es, tstamp) \
 291         __print_tstamp(buf, (es)->tstamp, (es)->tstamp ## _hi)
 292
 293 static ssize_t ext4_attr_show(struct kobject *kobj,
 294                               struct attribute *attr, char *buf)
 295 {
 296         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 297                                                 s_kobj);
 298         struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 299         void *ptr = calc_ptr(a, sbi);
 300
 301         switch (a->attr_id) {
 302         case attr_delayed_allocation_blocks:
 303                 return snprintf(buf, PAGE_SIZE, "%llu\n",
 304                                 (s64) EXT4_C2B(sbi,
 305                        percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
 306         case attr_session_write_kbytes:
 307                 return session_write_kbytes_show(sbi, buf);
 308         case attr_lifetime_write_kbytes:
 309                 return lifetime_write_kbytes_show(sbi, buf);
 310         case attr_reserved_clusters:
 311                 return snprintf(buf, PAGE_SIZE, "%llu\n",
 312                                 (unsigned long long)
 313                                 atomic64_read(&sbi->s_resv_clusters));
 314         case attr_sra_exceeded_retry_limit:
 315                 return snprintf(buf, PAGE_SIZE, "%llu\n",
 316                                 (unsigned long long)
 317                         percpu_counter_sum(&sbi->s_sra_exceeded_retry_limit));
 318         case attr_inode_readahead:
 319         case attr_pointer_ui:
 320                 if (!ptr)
 321                         return 0;
 322                 if (a->attr_ptr == ptr_ext4_super_block_offset)
 323                         return snprintf(buf, PAGE_SIZE, "%u\n",
 324                                         le32_to_cpup(ptr));
 325                 else
 326                         return snprintf(buf, PAGE_SIZE, "%u\n",
 327                                         *((unsigned int *) ptr));
 328         case attr_pointer_atomic:
 329                 if (!ptr)
 330                         return 0;
 331                 return snprintf(buf, PAGE_SIZE, "%d\n",
 332                                 atomic_read((atomic_t *) ptr));
 333         case attr_feature:
 334                 return snprintf(buf, PAGE_SIZE, "supported\n");
 335         case attr_first_error_time:
 336                 return print_tstamp(buf, sbi->s_es, s_first_error_time);
 337         case attr_last_error_time:
 338                 return print_tstamp(buf, sbi->s_es, s_last_error_time);
 339         case attr_journal_task:
 340                 return journal_task_show(sbi, buf);
 341         }
 342
 343         return 0;
 344 }
 345
 346 static ssize_t ext4_attr_store(struct kobject *kobj,
 347                                struct attribute *attr,
 348                                const char *buf, size_t len)
 349 {
 350         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 351                                                 s_kobj);
 352         struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 353         void *ptr = calc_ptr(a, sbi);
 354         unsigned long t;
 355         int ret;
 356
 357         switch (a->attr_id) {
 358         case attr_reserved_clusters:
 359                 return reserved_clusters_store(sbi, buf, len);
 360         case attr_pointer_ui:
 361                 if (!ptr)
 362                         return 0;
 363                 ret = kstrtoul(skip_spaces(buf), 0, &t);
 364                 if (ret)
 365                         return ret;
 366                 if (a->attr_ptr == ptr_ext4_super_block_offset)
 367                         *((__le32 *) ptr) = cpu_to_le32(t);
 368                 else
 369                         *((unsigned int *) ptr) = t;
 370                 return len;
 371         case attr_inode_readahead:
 372                 return inode_readahead_blks_store(sbi, buf, len);
 373         case attr_trigger_test_error:
 374                 return trigger_test_error(sbi, buf, len);
 375         }
 376         return 0;
 377 }
 378
 379 static void ext4_sb_release(struct kobject *kobj)
 380 {
 381         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 382                                                 s_kobj);
 383         complete(&sbi->s_kobj_unregister);
 384 }
 385
 386 static void ext4_feat_release(struct kobject *kobj)
 387 {
 388         kfree(kobj);
 389 }
 390
 391 static const struct sysfs_ops ext4_attr_ops = {
 392         .show   = ext4_attr_show,
 393         .store  = ext4_attr_store,
 394 };
 395
 396 static struct kobj_type ext4_sb_ktype = {
 397         .default_groups = ext4_groups,
 398         .sysfs_ops      = &ext4_attr_ops,
 399         .release        = ext4_sb_release,
 400 };
 401
 402 static struct kobj_type ext4_feat_ktype = {
 403         .default_groups = ext4_feat_groups,
 404         .sysfs_ops      = &ext4_attr_ops,
 405         .release        = ext4_feat_release,
 406 };
 407
 408 static struct kobject *ext4_root;
 409
 410 static struct kobject *ext4_feat;
 411
 412 int ext4_register_sysfs(struct super_block *sb)
 413 {
 414         struct ext4_sb_info *sbi = EXT4_SB(sb);
 415         int err;
 416
 417         init_completion(&sbi->s_kobj_unregister);
 418         err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, ext4_root,
 419                                    "%s", sb->s_id);
 420         if (err) {
 421                 kobject_put(&sbi->s_kobj);
 422                 wait_for_completion(&sbi->s_kobj_unregister);
 423                 return err;
 424         }
 425
 426         if (ext4_proc_root)
 427                 sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
 428         if (sbi->s_proc) {
 429                 proc_create_single_data("options", S_IRUGO, sbi->s_proc,
 430                                 ext4_seq_options_show, sb);
 431                 proc_create_single_data("es_shrinker_info", S_IRUGO,
 432                                 sbi->s_proc, ext4_seq_es_shrinker_info_show,
 433                                 sb);
 434                 proc_create_seq_data("mb_groups", S_IRUGO, sbi->s_proc,
 435                                 &ext4_mb_seq_groups_ops, sb);
 436         }
 437         return 0;
 438 }
 439
 440 void ext4_unregister_sysfs(struct super_block *sb)
 441 {
 442         struct ext4_sb_info *sbi = EXT4_SB(sb);
 443
 444         if (sbi->s_proc)
 445                 remove_proc_subtree(sb->s_id, ext4_proc_root);
 446         kobject_del(&sbi->s_kobj);
 447 }
 448
 449 int __init ext4_init_sysfs(void)
 450 {
 451         int ret;
 452
 453         ext4_root = kobject_create_and_add("ext4", fs_kobj);
 454         if (!ext4_root)
 455                 return -ENOMEM;
 456
 457         ext4_feat = kzalloc(sizeof(*ext4_feat), GFP_KERNEL);
 458         if (!ext4_feat) {
 459                 ret = -ENOMEM;
 460                 goto root_err;
 461         }
 462
 463         ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype,
 464                                    ext4_root, "features");
 465         if (ret)
 466                 goto feat_err;
 467
 468         ext4_proc_root = proc_mkdir(proc_dirname, NULL);
 469         return ret;
 470
 471 feat_err:
 472         kobject_put(ext4_feat);
 473         ext4_feat = NULL;
 474 root_err:
 475         kobject_put(ext4_root);
 476         ext4_root = NULL;
 477         return ret;
 478 }
 479
 480 void ext4_exit_sysfs(void)
 481 {
 482         kobject_put(ext4_feat);
 483         ext4_feat = NULL;
 484         kobject_put(ext4_root);
 485         ext4_root = NULL;
 486         remove_proc_entry(proc_dirname, NULL);
 487         ext4_proc_root = NULL;
 488 }
 489