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_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_attr *a,
  53                                          struct ext4_sb_info *sbi, char *buf)
  54 {
  55         struct super_block *sb = sbi->s_buddy_cache->i_sb;
  56
  57         if (!sb->s_bdev->bd_part)
  58                 return snprintf(buf, PAGE_SIZE, "0\n");
  59         return snprintf(buf, PAGE_SIZE, "%lu\n",
  60                         (part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
  61                          sbi->s_sectors_written_start) >> 1);
  62 }
  63
  64 static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
  65                                           struct ext4_sb_info *sbi, char *buf)
  66 {
  67         struct super_block *sb = sbi->s_buddy_cache->i_sb;
  68
  69         if (!sb->s_bdev->bd_part)
  70                 return snprintf(buf, PAGE_SIZE, "0\n");
  71         return snprintf(buf, PAGE_SIZE, "%llu\n",
  72                         (unsigned long long)(sbi->s_kbytes_written +
  73                         ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
  74                           EXT4_SB(sb)->s_sectors_written_start) >> 1)));
  75 }
  76
  77 static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
  78                                           struct ext4_sb_info *sbi,
  79                                           const char *buf, size_t count)
  80 {
  81         unsigned long t;
  82         int ret;
  83
  84         ret = kstrtoul(skip_spaces(buf), 0, &t);
  85         if (ret)
  86                 return ret;
  87
  88         if (t && (!is_power_of_2(t) || t > 0x40000000))
  89                 return -EINVAL;
  90
  91         sbi->s_inode_readahead_blks = t;
  92         return count;
  93 }
  94
  95 static ssize_t reserved_clusters_store(struct ext4_attr *a,
  96                                    struct ext4_sb_info *sbi,
  97                                    const char *buf, size_t count)
  98 {
  99         unsigned long long val;
 100         ext4_fsblk_t clusters = (ext4_blocks_count(sbi->s_es) >>
 101                                  sbi->s_cluster_bits);
 102         int ret;
 103
 104         ret = kstrtoull(skip_spaces(buf), 0, &val);
 105         if (ret || val >= clusters)
 106                 return -EINVAL;
 107
 108         atomic64_set(&sbi->s_resv_clusters, val);
 109         return count;
 110 }
 111
 112 static ssize_t trigger_test_error(struct ext4_attr *a,
 113                                   struct ext4_sb_info *sbi,
 114                                   const char *buf, size_t count)
 115 {
 116         int len = count;
 117
 118         if (!capable(CAP_SYS_ADMIN))
 119                 return -EPERM;
 120
 121         if (len && buf[len-1] == '\n')
 122                 len--;
 123
 124         if (len)
 125                 ext4_error(sbi->s_sb, "%.*s", len, buf);
 126         return count;
 127 }
 128
 129 #define EXT4_ATTR(_name,_mode,_id)                                      \
 130 static struct ext4_attr ext4_attr_##_name = {                           \
 131         .attr = {.name = __stringify(_name), .mode = _mode },           \
 132         .attr_id = attr_##_id,                                          \
 133 }
 134
 135 #define EXT4_ATTR_FUNC(_name,_mode)  EXT4_ATTR(_name,_mode,_name)
 136
 137 #define EXT4_ATTR_FEATURE(_name)   EXT4_ATTR(_name, 0444, feature)
 138
 139 #define EXT4_ATTR_OFFSET(_name,_mode,_id,_struct,_elname)       \
 140 static struct ext4_attr ext4_attr_##_name = {                   \
 141         .attr = {.name = __stringify(_name), .mode = _mode },   \
 142         .attr_id = attr_##_id,                                  \
 143         .attr_ptr = ptr_##_struct##_offset,                     \
 144         .u = {                                                  \
 145                 .offset = offsetof(struct _struct, _elname),\
 146         },                                                      \
 147 }
 148
 149 #define EXT4_RO_ATTR_ES_UI(_name,_elname)                               \
 150         EXT4_ATTR_OFFSET(_name, 0444, pointer_ui, ext4_super_block, _elname)
 151
 152 #define EXT4_RW_ATTR_SBI_UI(_name,_elname)      \
 153         EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)
 154
 155 #define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \
 156 static struct ext4_attr ext4_attr_##_name = {                   \
 157         .attr = {.name = __stringify(_name), .mode = _mode },   \
 158         .attr_id = attr_##_id,                                  \
 159         .attr_ptr = ptr_explicit,                               \
 160         .u = {                                                  \
 161                 .explicit_ptr = _ptr,                           \
 162         },                                                      \
 163 }
 164
 165 #define ATTR_LIST(name) &ext4_attr_##name.attr
 166
 167 EXT4_ATTR_FUNC(delayed_allocation_blocks, 0444);
 168 EXT4_ATTR_FUNC(session_write_kbytes, 0444);
 169 EXT4_ATTR_FUNC(lifetime_write_kbytes, 0444);
 170 EXT4_ATTR_FUNC(reserved_clusters, 0644);
 171
 172 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead,
 173                  ext4_sb_info, s_inode_readahead_blks);
 174 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
 175 EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
 176 EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
 177 EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
 178 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
 179 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
 180 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
 181 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
 182 EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
 183 EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
 184 EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
 185 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
 186 EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
 187 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
 188 EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
 189 EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
 190 EXT4_RO_ATTR_ES_UI(first_error_time, s_first_error_time);
 191 EXT4_RO_ATTR_ES_UI(last_error_time, s_last_error_time);
 192
 193 static unsigned int old_bump_val = 128;
 194 EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
 195
 196 static struct attribute *ext4_attrs[] = {
 197         ATTR_LIST(delayed_allocation_blocks),
 198         ATTR_LIST(session_write_kbytes),
 199         ATTR_LIST(lifetime_write_kbytes),
 200         ATTR_LIST(reserved_clusters),
 201         ATTR_LIST(inode_readahead_blks),
 202         ATTR_LIST(inode_goal),
 203         ATTR_LIST(mb_stats),
 204         ATTR_LIST(mb_max_to_scan),
 205         ATTR_LIST(mb_min_to_scan),
 206         ATTR_LIST(mb_order2_req),
 207         ATTR_LIST(mb_stream_req),
 208         ATTR_LIST(mb_group_prealloc),
 209         ATTR_LIST(max_writeback_mb_bump),
 210         ATTR_LIST(extent_max_zeroout_kb),
 211         ATTR_LIST(trigger_fs_error),
 212         ATTR_LIST(err_ratelimit_interval_ms),
 213         ATTR_LIST(err_ratelimit_burst),
 214         ATTR_LIST(warning_ratelimit_interval_ms),
 215         ATTR_LIST(warning_ratelimit_burst),
 216         ATTR_LIST(msg_ratelimit_interval_ms),
 217         ATTR_LIST(msg_ratelimit_burst),
 218         ATTR_LIST(errors_count),
 219         ATTR_LIST(first_error_time),
 220         ATTR_LIST(last_error_time),
 221         NULL,
 222 };
 223
 224 /* Features this copy of ext4 supports */
 225 EXT4_ATTR_FEATURE(lazy_itable_init);
 226 EXT4_ATTR_FEATURE(batched_discard);
 227 EXT4_ATTR_FEATURE(meta_bg_resize);
 228 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 229 EXT4_ATTR_FEATURE(encryption);
 230 #endif
 231 EXT4_ATTR_FEATURE(metadata_csum_seed);
 232
 233 static struct attribute *ext4_feat_attrs[] = {
 234         ATTR_LIST(lazy_itable_init),
 235         ATTR_LIST(batched_discard),
 236         ATTR_LIST(meta_bg_resize),
 237 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 238         ATTR_LIST(encryption),
 239 #endif
 240         ATTR_LIST(metadata_csum_seed),
 241         NULL,
 242 };
 243
 244 static void *calc_ptr(struct ext4_attr *a, struct ext4_sb_info *sbi)
 245 {
 246         switch (a->attr_ptr) {
 247         case ptr_explicit:
 248                 return a->u.explicit_ptr;
 249         case ptr_ext4_sb_info_offset:
 250                 return (void *) (((char *) sbi) + a->u.offset);
 251         case ptr_ext4_super_block_offset:
 252                 return (void *) (((char *) sbi->s_es) + a->u.offset);
 253         }
 254         return NULL;
 255 }
 256
 257 static ssize_t ext4_attr_show(struct kobject *kobj,
 258                               struct attribute *attr, char *buf)
 259 {
 260         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 261                                                 s_kobj);
 262         struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 263         void *ptr = calc_ptr(a, sbi);
 264
 265         switch (a->attr_id) {
 266         case attr_delayed_allocation_blocks:
 267                 return snprintf(buf, PAGE_SIZE, "%llu\n",
 268                                 (s64) EXT4_C2B(sbi,
 269                        percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
 270         case attr_session_write_kbytes:
 271                 return session_write_kbytes_show(a, sbi, buf);
 272         case attr_lifetime_write_kbytes:
 273                 return lifetime_write_kbytes_show(a, sbi, buf);
 274         case attr_reserved_clusters:
 275                 return snprintf(buf, PAGE_SIZE, "%llu\n",
 276                                 (unsigned long long)
 277                                 atomic64_read(&sbi->s_resv_clusters));
 278         case attr_inode_readahead:
 279         case attr_pointer_ui:
 280                 if (!ptr)
 281                         return 0;
 282                 return snprintf(buf, PAGE_SIZE, "%u\n",
 283                                 *((unsigned int *) ptr));
 284         case attr_pointer_atomic:
 285                 if (!ptr)
 286                         return 0;
 287                 return snprintf(buf, PAGE_SIZE, "%d\n",
 288                                 atomic_read((atomic_t *) ptr));
 289         case attr_feature:
 290                 return snprintf(buf, PAGE_SIZE, "supported\n");
 291         }
 292
 293         return 0;
 294 }
 295
 296 static ssize_t ext4_attr_store(struct kobject *kobj,
 297                                struct attribute *attr,
 298                                const char *buf, size_t len)
 299 {
 300         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 301                                                 s_kobj);
 302         struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
 303         void *ptr = calc_ptr(a, sbi);
 304         unsigned long t;
 305         int ret;
 306
 307         switch (a->attr_id) {
 308         case attr_reserved_clusters:
 309                 return reserved_clusters_store(a, sbi, buf, len);
 310         case attr_pointer_ui:
 311                 if (!ptr)
 312                         return 0;
 313                 ret = kstrtoul(skip_spaces(buf), 0, &t);
 314                 if (ret)
 315                         return ret;
 316                 *((unsigned int *) ptr) = t;
 317                 return len;
 318         case attr_inode_readahead:
 319                 return inode_readahead_blks_store(a, sbi, buf, len);
 320         case attr_trigger_test_error:
 321                 return trigger_test_error(a, sbi, buf, len);
 322         }
 323         return 0;
 324 }
 325
 326 static void ext4_sb_release(struct kobject *kobj)
 327 {
 328         struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
 329                                                 s_kobj);
 330         complete(&sbi->s_kobj_unregister);
 331 }
 332
 333 static void ext4_kset_release(struct kobject *kobj)
 334 {
 335         struct kset *kset = container_of(kobj, struct kset, kobj);
 336
 337         kfree(kset);
 338 }
 339
 340 static const struct sysfs_ops ext4_attr_ops = {
 341         .show   = ext4_attr_show,
 342         .store  = ext4_attr_store,
 343 };
 344
 345 static struct kobj_type ext4_sb_ktype = {
 346         .default_attrs  = ext4_attrs,
 347         .sysfs_ops      = &ext4_attr_ops,
 348         .release        = ext4_sb_release,
 349 };
 350
 351 static struct kobj_type ext4_ktype = {
 352         .sysfs_ops      = &ext4_attr_ops,
 353         .release        = ext4_kset_release,
 354 };
 355
 356 static struct kset *ext4_kset;
 357
 358 static struct kobj_type ext4_feat_ktype = {
 359         .default_attrs  = ext4_feat_attrs,
 360         .sysfs_ops      = &ext4_attr_ops,
 361         .release        = (void (*)(struct kobject *))kfree,
 362 };
 363
 364 static struct kobject *ext4_feat;
 365
 366 #define PROC_FILE_SHOW_DEFN(name) \
 367 static int name##_open(struct inode *inode, struct file *file) \
 368 { \
 369         return single_open(file, ext4_seq_##name##_show, PDE_DATA(inode)); \
 370 } \
 371 \
 372 static const struct file_operations ext4_seq_##name##_fops = { \
 373         .open           = name##_open, \
 374         .read           = seq_read, \
 375         .llseek         = seq_lseek, \
 376         .release        = single_release, \
 377 }
 378
 379 #define PROC_FILE_LIST(name) \
 380         { __stringify(name), &ext4_seq_##name##_fops }
 381
 382 PROC_FILE_SHOW_DEFN(es_shrinker_info);
 383 PROC_FILE_SHOW_DEFN(options);
 384
 385 static const struct ext4_proc_files {
 386         const char *name;
 387         const struct file_operations *fops;
 388 } proc_files[] = {
 389         PROC_FILE_LIST(options),
 390         PROC_FILE_LIST(es_shrinker_info),
 391         PROC_FILE_LIST(mb_groups),
 392         { NULL, NULL },
 393 };
 394
 395 int ext4_register_sysfs(struct super_block *sb)
 396 {
 397         struct ext4_sb_info *sbi = EXT4_SB(sb);
 398         const struct ext4_proc_files *p;
 399         int err;
 400
 401         sbi->s_kobj.kset = ext4_kset;
 402         init_completion(&sbi->s_kobj_unregister);
 403         err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, NULL,
 404                                    "%s", sb->s_id);
 405         if (err) {
 406                 kobject_put(&sbi->s_kobj);
 407                 wait_for_completion(&sbi->s_kobj_unregister);
 408                 return err;
 409         }
 410
 411         if (ext4_proc_root)
 412                 sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
 413
 414         if (sbi->s_proc) {
 415                 for (p = proc_files; p->name; p++)
 416                         proc_create_data(p->name, S_IRUGO, sbi->s_proc,
 417                                          p->fops, sb);
 418         }
 419         return 0;
 420 }
 421
 422 void ext4_unregister_sysfs(struct super_block *sb)
 423 {
 424         struct ext4_sb_info *sbi = EXT4_SB(sb);
 425         const struct ext4_proc_files *p;
 426
 427         if (sbi->s_proc) {
 428                 for (p = proc_files; p->name; p++)
 429                         remove_proc_entry(p->name, sbi->s_proc);
 430                 remove_proc_entry(sb->s_id, ext4_proc_root);
 431         }
 432         kobject_del(&sbi->s_kobj);
 433 }
 434
 435 int __init ext4_init_sysfs(void)
 436 {
 437         int ret;
 438
 439         ext4_kset = kzalloc(sizeof(*ext4_kset), GFP_KERNEL);
 440         if (!ext4_kset)
 441                 return -ENOMEM;
 442
 443         kobject_set_name(&ext4_kset->kobj, "ext4");
 444         ext4_kset->kobj.parent = fs_kobj;
 445         ext4_kset->kobj.ktype = &ext4_ktype;
 446         ret = kset_register(ext4_kset);
 447         if (ret)
 448                 goto kset_err;
 449
 450         ext4_feat = kzalloc(sizeof(*ext4_feat), GFP_KERNEL);
 451         if (!ext4_feat) {
 452                 ret = -ENOMEM;
 453                 goto kset_err;
 454         }
 455
 456         ext4_feat->kset = ext4_kset;
 457         ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype,
 458                                    NULL, "features");
 459         if (ret)
 460                 goto feat_err;
 461
 462         ext4_proc_root = proc_mkdir(proc_dirname, NULL);
 463         return ret;
 464
 465 feat_err:
 466         kobject_put(ext4_feat);
 467 kset_err:
 468         kset_unregister(ext4_kset);
 469         ext4_kset = NULL;
 470         return ret;
 471 }
 472
 473 void ext4_exit_sysfs(void)
 474 {
 475         kobject_put(ext4_feat);
 476         kset_unregister(ext4_kset);
 477         ext4_kset = NULL;
 478         remove_proc_entry(proc_dirname, NULL);
 479         ext4_proc_root = NULL;
 480 }
 481