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->nsets; i++)
 117                 dump_bset(b, b->sets[i].data,
 118                           bset_block_offset(b, b->sets[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->sets->data;
 143         inmemory = b->sets->data;
 144
 145         bkey_copy(&v->key, &b->key);
 146         v->written = 0;
 147         v->level = b->level;
 148
 149         bio = bch_bbio_alloc(b->c);
 150         bio->bi_bdev            = PTR_CACHE(b->c, &b->key, 0)->bdev;
 151         bio->bi_iter.bi_sector  = PTR_OFFSET(&b->key, 0);
 152         bio->bi_iter.bi_size    = KEY_SIZE(&v->key) << 9;
 153         bch_bio_map(bio, sorted);
 154
 155         submit_bio_wait(REQ_META|READ_SYNC, bio);
 156         bch_bbio_free(bio, b->c);
 157
 158         memcpy(ondisk, sorted, KEY_SIZE(&v->key) << 9);
 159
 160         bch_btree_node_read_done(v);
 161         sorted = v->sets->data;
 162
 163         if (inmemory->keys != sorted->keys ||
 164             memcmp(inmemory->start,
 165                    sorted->start,
 166                    (void *) bset_bkey_last(inmemory) - (void *) inmemory->start)) {
 167                 struct bset *i;
 168                 unsigned j;
 169
 170                 console_lock();
 171
 172                 printk(KERN_ERR "*** in memory:\n");
 173                 dump_bset(b, inmemory, 0);
 174
 175                 printk(KERN_ERR "*** read back in:\n");
 176                 dump_bset(v, sorted, 0);
 177
 178                 for_each_written_bset(b, ondisk, i) {
 179                         unsigned block = ((void *) i - (void *) ondisk) /
 180                                 block_bytes(b->c);
 181
 182                         printk(KERN_ERR "*** on disk block %u:\n", block);
 183                         dump_bset(b, i, block);
 184                 }
 185
 186                 printk(KERN_ERR "*** block %zu not written\n",
 187                        ((void *) i - (void *) ondisk) / block_bytes(b->c));
 188
 189                 for (j = 0; j < inmemory->keys; j++)
 190                         if (inmemory->d[j] != sorted->d[j])
 191                                 break;
 192
 193                 printk(KERN_ERR "b->written %u\n", b->written);
 194
 195                 console_unlock();
 196                 panic("verify failed at %u\n", j);
 197         }
 198
 199         mutex_unlock(&b->c->verify_lock);
 200         up(&b->io_mutex);
 201 }
 202
 203 void bch_data_verify(struct cached_dev *dc, struct bio *bio)
 204 {
 205         char name[BDEVNAME_SIZE];
 206         struct bio *check;
 207         struct bio_vec bv, *bv2;
 208         struct bvec_iter iter;
 209         int i;
 210
 211         check = bio_clone(bio, GFP_NOIO);
 212         if (!check)
 213                 return;
 214
 215         if (bio_alloc_pages(check, GFP_NOIO))
 216                 goto out_put;
 217
 218         submit_bio_wait(READ_SYNC, check);
 219
 220         bio_for_each_segment(bv, bio, iter) {
 221                 void *p1 = kmap_atomic(bv.bv_page);
 222                 void *p2 = page_address(check->bi_io_vec[iter.bi_idx].bv_page);
 223
 224                 cache_set_err_on(memcmp(p1 + bv.bv_offset,
 225                                         p2 + bv.bv_offset,
 226                                         bv.bv_len),
 227                                  dc->disk.c,
 228                                  "verify failed at dev %s sector %llu",
 229                                  bdevname(dc->bdev, name),
 230                                  (uint64_t) bio->bi_iter.bi_sector);
 231
 232                 kunmap_atomic(p1);
 233         }
 234
 235         bio_for_each_segment_all(bv2, check, i)
 236                 __free_page(bv2->bv_page);
 237 out_put:
 238         bio_put(check);
 239 }
 240
 241 int __bch_count_data(struct btree *b)
 242 {
 243         unsigned ret = 0;
 244         struct btree_iter iter;
 245         struct bkey *k;
 246
 247         if (!b->level)
 248                 for_each_key(b, k, &iter)
 249                         ret += KEY_SIZE(k);
 250         return ret;
 251 }
 252
 253 void __bch_check_keys(struct btree *b, const char *fmt, ...)
 254 {
 255         va_list args;
 256         struct bkey *k, *p = NULL;
 257         struct btree_iter iter;
 258         const char *err;
 259
 260         for_each_key(b, k, &iter) {
 261                 if (!b->level) {
 262                         err = "Keys out of order";
 263                         if (p && bkey_cmp(&START_KEY(p), &START_KEY(k)) > 0)
 264                                 goto bug;
 265
 266                         if (bch_ptr_invalid(b, k))
 267                                 continue;
 268
 269                         err =  "Overlapping keys";
 270                         if (p && bkey_cmp(p, &START_KEY(k)) > 0)
 271                                 goto bug;
 272                 } else {
 273                         if (bch_ptr_bad(b, k))
 274                                 continue;
 275
 276                         err = "Duplicate keys";
 277                         if (p && !bkey_cmp(p, k))
 278                                 goto bug;
 279                 }
 280                 p = k;
 281         }
 282
 283         err = "Key larger than btree node key";
 284         if (p && bkey_cmp(p, &b->key) > 0)
 285                 goto bug;
 286
 287         return;
 288 bug:
 289         bch_dump_bucket(b);
 290
 291         va_start(args, fmt);
 292         vprintk(fmt, args);
 293         va_end(args);
 294
 295         panic("bcache error: %s:\n", err);
 296 }
 297
 298 void bch_btree_iter_next_check(struct btree_iter *iter)
 299 {
 300         struct bkey *k = iter->data->k, *next = bkey_next(k);
 301
 302         if (next < iter->data->end &&
 303             bkey_cmp(k, iter->b->level ? next : &START_KEY(next)) > 0) {
 304                 bch_dump_bucket(iter->b);
 305                 panic("Key skipped backwards\n");
 306         }
 307 }
 308
 309 #endif
 310
 311 #ifdef CONFIG_DEBUG_FS
 312
 313 /* XXX: cache set refcounting */
 314
 315 struct dump_iterator {
 316         char                    buf[PAGE_SIZE];
 317         size_t                  bytes;
 318         struct cache_set        *c;
 319         struct keybuf           keys;
 320 };
 321
 322 static bool dump_pred(struct keybuf *buf, struct bkey *k)
 323 {
 324         return true;
 325 }
 326
 327 static ssize_t bch_dump_read(struct file *file, char __user *buf,
 328                              size_t size, loff_t *ppos)
 329 {
 330         struct dump_iterator *i = file->private_data;
 331         ssize_t ret = 0;
 332         char kbuf[80];
 333
 334         while (size) {
 335                 struct keybuf_key *w;
 336                 unsigned bytes = min(i->bytes, size);
 337
 338                 int err = copy_to_user(buf, i->buf, bytes);
 339                 if (err)
 340                         return err;
 341
 342                 ret      += bytes;
 343                 buf      += bytes;
 344                 size     -= bytes;
 345                 i->bytes -= bytes;
 346                 memmove(i->buf, i->buf + bytes, i->bytes);
 347
 348                 if (i->bytes)
 349                         break;
 350
 351                 w = bch_keybuf_next_rescan(i->c, &i->keys, &MAX_KEY, dump_pred);
 352                 if (!w)
 353                         break;
 354
 355                 bch_bkey_to_text(kbuf, sizeof(kbuf), &w->key);
 356                 i->bytes = snprintf(i->buf, PAGE_SIZE, "%s\n", kbuf);
 357                 bch_keybuf_del(&i->keys, w);
 358         }
 359
 360         return ret;
 361 }
 362
 363 static int bch_dump_open(struct inode *inode, struct file *file)
 364 {
 365         struct cache_set *c = inode->i_private;
 366         struct dump_iterator *i;
 367
 368         i = kzalloc(sizeof(struct dump_iterator), GFP_KERNEL);
 369         if (!i)
 370                 return -ENOMEM;
 371
 372         file->private_data = i;
 373         i->c = c;
 374         bch_keybuf_init(&i->keys);
 375         i->keys.last_scanned = KEY(0, 0, 0);
 376
 377         return 0;
 378 }
 379
 380 static int bch_dump_release(struct inode *inode, struct file *file)
 381 {
 382         kfree(file->private_data);
 383         return 0;
 384 }
 385
 386 static const struct file_operations cache_set_debug_ops = {
 387         .owner          = THIS_MODULE,
 388         .open           = bch_dump_open,
 389         .read           = bch_dump_read,
 390         .release        = bch_dump_release
 391 };
 392
 393 void bch_debug_init_cache_set(struct cache_set *c)
 394 {
 395         if (!IS_ERR_OR_NULL(debug)) {
 396                 char name[50];
 397                 snprintf(name, 50, "bcache-%pU", c->sb.set_uuid);
 398
 399                 c->debug = debugfs_create_file(name, 0400, debug, c,
 400                                                &cache_set_debug_ops);
 401         }
 402 }
 403
 404 #endif
 405
 406 void bch_debug_exit(void)
 407 {
 408         if (!IS_ERR_OR_NULL(debug))
 409                 debugfs_remove_recursive(debug);
 410 }
 411
 412 int __init bch_debug_init(struct kobject *kobj)
 413 {
 414         int ret = 0;
 415
 416         debug = debugfs_create_dir("bcache", NULL);
 417         return ret;
 418 }