drivers/md/bcache/debug.c

   1 /*
   2  * Assorted bcache debug code
   3  *
   4  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
   5  * Copyright 2012 Google, Inc.
   6  */
   7
   8 #include "bcache.h"
   9 #include "btree.h"
  10 #include "debug.h"
  11
  12 #include <linux/console.h>
  13 #include <linux/debugfs.h>
  14 #include <linux/module.h>
  15 #include <linux/random.h>
  16 #include <linux/seq_file.h>
  17
  18 static struct dentry *debug;
  19
  20 const char *bch_ptr_status(struct cache_set *c, const struct bkey *k)
  21 {
  22         unsigned i;
  23
  24         for (i = 0; i < KEY_PTRS(k); i++)
  25                 if (ptr_available(c, k, i)) {
  26                         struct cache *ca = PTR_CACHE(c, k, i);
  27                         size_t bucket = PTR_BUCKET_NR(c, k, i);
  28                         size_t r = bucket_remainder(c, PTR_OFFSET(k, i));
  29
  30                         if (KEY_SIZE(k) + r > c->sb.bucket_size)
  31                                 return "bad, length too big";
  32                         if (bucket <  ca->sb.first_bucket)
  33                                 return "bad, short offset";
  34                         if (bucket >= ca->sb.nbuckets)
  35                                 return "bad, offset past end of device";
  36                         if (ptr_stale(c, k, i))
  37                                 return "stale";
  38                 }
  39
  40         if (!bkey_cmp(k, &ZERO_KEY))
  41                 return "bad, null key";
  42         if (!KEY_PTRS(k))
  43                 return "bad, no pointers";
  44         if (!KEY_SIZE(k))
  45                 return "zeroed key";
  46         return "";
  47 }
  48
  49 int bch_bkey_to_text(char *buf, size_t size, const struct bkey *k)
  50 {
  51         unsigned i = 0;
  52         char *out = buf, *end = buf + size;
  53
  54 #define p(...)  (out += scnprintf(out, end - out, __VA_ARGS__))
  55
  56         p("%llu:%llu len %llu -> [", KEY_INODE(k), KEY_START(k), KEY_SIZE(k));
  57
  58         for (i = 0; i < KEY_PTRS(k); i++) {
  59                 if (i)
  60                         p(", ");
  61
  62                 if (PTR_DEV(k, i) == PTR_CHECK_DEV)
  63                         p("check dev");
  64                 else
  65                         p("%llu:%llu gen %llu", PTR_DEV(k, i),
  66                           PTR_OFFSET(k, i), PTR_GEN(k, i));
  67         }
  68
  69         p("]");
  70
  71         if (KEY_DIRTY(k))
  72                 p(" dirty");
  73         if (KEY_CSUM(k))
  74                 p(" cs%llu %llx", KEY_CSUM(k), k->ptr[1]);
  75 #undef p
  76         return out - buf;
  77 }
  78
  79 #ifdef CONFIG_BCACHE_DEBUG
  80
  81 static void dump_bset(struct btree *b, struct bset *i, unsigned set)
  82 {
  83         struct bkey *k, *next;
  84         unsigned j;
  85         char buf[80];
  86
  87         for (k = i->start; k < bset_bkey_last(i); k = next) {
  88                 next = bkey_next(k);
  89
  90                 bch_bkey_to_text(buf, sizeof(buf), k);
  91                 printk(KERN_ERR "b %u k %zi/%u: %s", set,
  92                        (uint64_t *) k - i->d, i->keys, buf);
  93
  94                 for (j = 0; j < KEY_PTRS(k); j++) {
  95                         size_t n = PTR_BUCKET_NR(b->c, k, j);
  96                         printk(" bucket %zu", n);
  97
  98                         if (n >= b->c->sb.first_bucket && n < b->c->sb.nbuckets)
  99                                 printk(" prio %i",
 100                                        PTR_BUCKET(b->c, k, j)->prio);
 101                 }
 102
 103                 printk(" %s\n", bch_ptr_status(b->c, k));
 104
 105                 if (next < bset_bkey_last(i) &&
 106                     bkey_cmp(k, !b->level ? &START_KEY(next) : next) > 0)
 107                         printk(KERN_ERR "Key skipped backwards\n");
 108         }
 109 }
 110
 111 static void bch_dump_bucket(struct btree *b)
 112 {
 113         unsigned i;
 114
 115         console_lock();
 116         for (i = 0; i <= b->keys.nsets; i++)
 117                 dump_bset(b, b->keys.set[i].data,
 118                           bset_block_offset(b, b->keys.set[i].data));
 119         console_unlock();
 120 }
 121
 122 #define for_each_written_bset(b, start, i)                              \
 123         for (i = (start);                                               \
 124              (void *) i < (void *) (start) + (KEY_SIZE(&b->key) << 9) &&\
 125              i->seq == (start)->seq;                                    \
 126              i = (void *) i + set_blocks(i, block_bytes(b->c)) *        \
 127                  block_bytes(b->c))
 128
 129 void bch_btree_verify(struct btree *b)
 130 {
 131         struct btree *v = b->c->verify_data;
 132         struct bset *ondisk, *sorted, *inmemory;
 133         struct bio *bio;
 134
 135         if (!b->c->verify || !b->c->verify_ondisk)
 136                 return;
 137
 138         down(&b->io_mutex);
 139         mutex_lock(&b->c->verify_lock);
 140
 141         ondisk = b->c->verify_ondisk;
 142         sorted = b->c->verify_data->keys.set->data;
 143         inmemory = b->keys.set->data;
 144
 145         bkey_copy(&v->key, &b->key);
 146         v->written = 0;
 147         v->level = b->level;
 148         v->keys.ops = b->keys.ops;
 149
 150         bio = bch_bbio_alloc(b->c);
 151         bio->bi_bdev            = PTR_CACHE(b->c, &b->key, 0)->bdev;
 152         bio->bi_iter.bi_sector  = PTR_OFFSET(&b->key, 0);
 153         bio->bi_iter.bi_size    = KEY_SIZE(&v->key) << 9;
 154         bch_bio_map(bio, sorted);
 155
 156         submit_bio_wait(REQ_META|READ_SYNC, bio);
 157         bch_bbio_free(bio, b->c);
 158
 159         memcpy(ondisk, sorted, KEY_SIZE(&v->key) << 9);
 160
 161         bch_btree_node_read_done(v);
 162         sorted = v->keys.set->data;
 163
 164         if (inmemory->keys != sorted->keys ||
 165             memcmp(inmemory->start,
 166                    sorted->start,
 167                    (void *) bset_bkey_last(inmemory) - (void *) inmemory->start)) {
 168                 struct bset *i;
 169                 unsigned j;
 170
 171                 console_lock();
 172
 173                 printk(KERN_ERR "*** in memory:\n");
 174                 dump_bset(b, inmemory, 0);
 175
 176                 printk(KERN_ERR "*** read back in:\n");
 177                 dump_bset(v, sorted, 0);
 178
 179                 for_each_written_bset(b, ondisk, i) {
 180                         unsigned block = ((void *) i - (void *) ondisk) /
 181                                 block_bytes(b->c);
 182
 183                         printk(KERN_ERR "*** on disk block %u:\n", block);
 184                         dump_bset(b, i, block);
 185                 }
 186
 187                 printk(KERN_ERR "*** block %zu not written\n",
 188                        ((void *) i - (void *) ondisk) / block_bytes(b->c));
 189
 190                 for (j = 0; j < inmemory->keys; j++)
 191                         if (inmemory->d[j] != sorted->d[j])
 192                                 break;
 193
 194                 printk(KERN_ERR "b->written %u\n", b->written);
 195
 196                 console_unlock();
 197                 panic("verify failed at %u\n", j);
 198         }
 199
 200         mutex_unlock(&b->c->verify_lock);
 201         up(&b->io_mutex);
 202 }
 203
 204 void bch_data_verify(struct cached_dev *dc, struct bio *bio)
 205 {
 206         char name[BDEVNAME_SIZE];
 207         struct bio *check;
 208         struct bio_vec bv, *bv2;
 209         struct bvec_iter iter;
 210         int i;
 211
 212         check = bio_clone(bio, GFP_NOIO);
 213         if (!check)
 214                 return;
 215
 216         if (bio_alloc_pages(check, GFP_NOIO))
 217                 goto out_put;
 218
 219         submit_bio_wait(READ_SYNC, check);
 220
 221         bio_for_each_segment(bv, bio, iter) {
 222                 void *p1 = kmap_atomic(bv.bv_page);
 223                 void *p2 = page_address(check->bi_io_vec[iter.bi_idx].bv_page);
 224
 225                 cache_set_err_on(memcmp(p1 + bv.bv_offset,
 226                                         p2 + bv.bv_offset,
 227                                         bv.bv_len),
 228                                  dc->disk.c,
 229                                  "verify failed at dev %s sector %llu",
 230                                  bdevname(dc->bdev, name),
 231                                  (uint64_t) bio->bi_iter.bi_sector);
 232
 233                 kunmap_atomic(p1);
 234         }
 235
 236         bio_for_each_segment_all(bv2, check, i)
 237                 __free_page(bv2->bv_page);
 238 out_put:
 239         bio_put(check);
 240 }
 241
 242 int __bch_count_data(struct btree *b)
 243 {
 244         unsigned ret = 0;
 245         struct btree_iter iter;
 246         struct bkey *k;
 247
 248         if (!b->level)
 249                 for_each_key(b, k, &iter)
 250                         ret += KEY_SIZE(k);
 251         return ret;
 252 }
 253
 254 void __bch_check_keys(struct btree *b, const char *fmt, ...)
 255 {
 256         va_list args;
 257         struct bkey *k, *p = NULL;
 258         struct btree_iter iter;
 259         const char *err;
 260
 261         for_each_key(b, k, &iter) {
 262                 if (!b->level) {
 263                         err = "Keys out of order";
 264                         if (p && bkey_cmp(&START_KEY(p), &START_KEY(k)) > 0)
 265                                 goto bug;
 266
 267                         if (bch_ptr_invalid(&b->keys, k))
 268                                 continue;
 269
 270                         err =  "Overlapping keys";
 271                         if (p && bkey_cmp(p, &START_KEY(k)) > 0)
 272                                 goto bug;
 273                 } else {
 274                         if (bch_ptr_bad(&b->keys, k))
 275                                 continue;
 276
 277                         err = "Duplicate keys";
 278                         if (p && !bkey_cmp(p, k))
 279                                 goto bug;
 280                 }
 281                 p = k;
 282         }
 283
 284         err = "Key larger than btree node key";
 285         if (p && bkey_cmp(p, &b->key) > 0)
 286                 goto bug;
 287
 288         return;
 289 bug:
 290         bch_dump_bucket(b);
 291
 292         va_start(args, fmt);
 293         vprintk(fmt, args);
 294         va_end(args);
 295
 296         panic("bcache error: %s:\n", err);
 297 }
 298
 299 void bch_btree_iter_next_check(struct btree_iter *iter)
 300 {
 301         struct bkey *k = iter->data->k, *next = bkey_next(k);
 302
 303         if (next < iter->data->end &&
 304             bkey_cmp(k, iter->b->level ? next : &START_KEY(next)) > 0) {
 305                 bch_dump_bucket(iter->b);
 306                 panic("Key skipped backwards\n");
 307         }
 308 }
 309
 310 #endif
 311
 312 #ifdef CONFIG_DEBUG_FS
 313
 314 /* XXX: cache set refcounting */
 315
 316 struct dump_iterator {
 317         char                    buf[PAGE_SIZE];
 318         size_t                  bytes;
 319         struct cache_set        *c;
 320         struct keybuf           keys;
 321 };
 322
 323 static bool dump_pred(struct keybuf *buf, struct bkey *k)
 324 {
 325         return true;
 326 }
 327
 328 static ssize_t bch_dump_read(struct file *file, char __user *buf,
 329                              size_t size, loff_t *ppos)
 330 {
 331         struct dump_iterator *i = file->private_data;
 332         ssize_t ret = 0;
 333         char kbuf[80];
 334
 335         while (size) {
 336                 struct keybuf_key *w;
 337                 unsigned bytes = min(i->bytes, size);
 338
 339                 int err = copy_to_user(buf, i->buf, bytes);
 340                 if (err)
 341                         return err;
 342
 343                 ret      += bytes;
 344                 buf      += bytes;
 345                 size     -= bytes;
 346                 i->bytes -= bytes;
 347                 memmove(i->buf, i->buf + bytes, i->bytes);
 348
 349                 if (i->bytes)
 350                         break;
 351
 352                 w = bch_keybuf_next_rescan(i->c, &i->keys, &MAX_KEY, dump_pred);
 353                 if (!w)
 354                         break;
 355
 356                 bch_bkey_to_text(kbuf, sizeof(kbuf), &w->key);
 357                 i->bytes = snprintf(i->buf, PAGE_SIZE, "%s\n", kbuf);
 358                 bch_keybuf_del(&i->keys, w);
 359         }
 360
 361         return ret;
 362 }
 363
 364 static int bch_dump_open(struct inode *inode, struct file *file)
 365 {
 366         struct cache_set *c = inode->i_private;
 367         struct dump_iterator *i;
 368
 369         i = kzalloc(sizeof(struct dump_iterator), GFP_KERNEL);
 370         if (!i)
 371                 return -ENOMEM;
 372
 373         file->private_data = i;
 374         i->c = c;
 375         bch_keybuf_init(&i->keys);
 376         i->keys.last_scanned = KEY(0, 0, 0);
 377
 378         return 0;
 379 }
 380
 381 static int bch_dump_release(struct inode *inode, struct file *file)
 382 {
 383         kfree(file->private_data);
 384         return 0;
 385 }
 386
 387 static const struct file_operations cache_set_debug_ops = {
 388         .owner          = THIS_MODULE,
 389         .open           = bch_dump_open,
 390         .read           = bch_dump_read,
 391         .release        = bch_dump_release
 392 };
 393
 394 void bch_debug_init_cache_set(struct cache_set *c)
 395 {
 396         if (!IS_ERR_OR_NULL(debug)) {
 397                 char name[50];
 398                 snprintf(name, 50, "bcache-%pU", c->sb.set_uuid);
 399
 400                 c->debug = debugfs_create_file(name, 0400, debug, c,
 401                                                &cache_set_debug_ops);
 402         }
 403 }
 404
 405 #endif
 406
 407 void bch_debug_exit(void)
 408 {
 409         if (!IS_ERR_OR_NULL(debug))
 410                 debugfs_remove_recursive(debug);
 411 }
 412
 413 int __init bch_debug_init(struct kobject *kobj)
 414 {
 415         int ret = 0;
 416
 417         debug = debugfs_create_dir("bcache", NULL);
 418         return ret;
 419 }