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, b->c) * block_bytes(b->c))
 127
 128 void bch_btree_verify(struct btree *b)
 129 {
 130         struct btree *v = b->c->verify_data;
 131         struct bset *ondisk, *sorted, *inmemory;
 132         struct bio *bio;
 133
 134         if (!b->c->verify || !b->c->verify_ondisk)
 135                 return;
 136
 137         down(&b->io_mutex);
 138         mutex_lock(&b->c->verify_lock);
 139
 140         ondisk = b->c->verify_ondisk;
 141         sorted = b->c->verify_data->sets->data;
 142         inmemory = b->sets->data;
 143
 144         bkey_copy(&v->key, &b->key);
 145         v->written = 0;
 146         v->level = b->level;
 147
 148         bio = bch_bbio_alloc(b->c);
 149         bio->bi_bdev            = PTR_CACHE(b->c, &b->key, 0)->bdev;
 150         bio->bi_iter.bi_sector  = PTR_OFFSET(&b->key, 0);
 151         bio->bi_iter.bi_size    = KEY_SIZE(&v->key) << 9;
 152         bch_bio_map(bio, sorted);
 153
 154         submit_bio_wait(REQ_META|READ_SYNC, bio);
 155         bch_bbio_free(bio, b->c);
 156
 157         memcpy(ondisk, sorted, KEY_SIZE(&v->key) << 9);
 158
 159         bch_btree_node_read_done(v);
 160         sorted = v->sets->data;
 161
 162         if (inmemory->keys != sorted->keys ||
 163             memcmp(inmemory->start,
 164                    sorted->start,
 165                    (void *) bset_bkey_last(inmemory) - (void *) inmemory->start)) {
 166                 struct bset *i;
 167                 unsigned j;
 168
 169                 console_lock();
 170
 171                 printk(KERN_ERR "*** in memory:\n");
 172                 dump_bset(b, inmemory, 0);
 173
 174                 printk(KERN_ERR "*** read back in:\n");
 175                 dump_bset(v, sorted, 0);
 176
 177                 for_each_written_bset(b, ondisk, i) {
 178                         unsigned block = ((void *) i - (void *) ondisk) /
 179                                 block_bytes(b->c);
 180
 181                         printk(KERN_ERR "*** on disk block %u:\n", block);
 182                         dump_bset(b, i, block);
 183                 }
 184
 185                 printk(KERN_ERR "*** block %zu not written\n",
 186                        ((void *) i - (void *) ondisk) / block_bytes(b->c));
 187
 188                 for (j = 0; j < inmemory->keys; j++)
 189                         if (inmemory->d[j] != sorted->d[j])
 190                                 break;
 191
 192                 printk(KERN_ERR "b->written %u\n", b->written);
 193
 194                 console_unlock();
 195                 panic("verify failed at %u\n", j);
 196         }
 197
 198         mutex_unlock(&b->c->verify_lock);
 199         up(&b->io_mutex);
 200 }
 201
 202 void bch_data_verify(struct cached_dev *dc, struct bio *bio)
 203 {
 204         char name[BDEVNAME_SIZE];
 205         struct bio *check;
 206         struct bio_vec bv, *bv2;
 207         struct bvec_iter iter;
 208         int i;
 209
 210         check = bio_clone(bio, GFP_NOIO);
 211         if (!check)
 212                 return;
 213
 214         if (bio_alloc_pages(check, GFP_NOIO))
 215                 goto out_put;
 216
 217         submit_bio_wait(READ_SYNC, check);
 218
 219         bio_for_each_segment(bv, bio, iter) {
 220                 void *p1 = kmap_atomic(bv.bv_page);
 221                 void *p2 = page_address(check->bi_io_vec[iter.bi_idx].bv_page);
 222
 223                 cache_set_err_on(memcmp(p1 + bv.bv_offset,
 224                                         p2 + bv.bv_offset,
 225                                         bv.bv_len),
 226                                  dc->disk.c,
 227                                  "verify failed at dev %s sector %llu",
 228                                  bdevname(dc->bdev, name),
 229                                  (uint64_t) bio->bi_iter.bi_sector);
 230
 231                 kunmap_atomic(p1);
 232         }
 233
 234         bio_for_each_segment_all(bv2, check, i)
 235                 __free_page(bv2->bv_page);
 236 out_put:
 237         bio_put(check);
 238 }
 239
 240 int __bch_count_data(struct btree *b)
 241 {
 242         unsigned ret = 0;
 243         struct btree_iter iter;
 244         struct bkey *k;
 245
 246         if (!b->level)
 247                 for_each_key(b, k, &iter)
 248                         ret += KEY_SIZE(k);
 249         return ret;
 250 }
 251
 252 void __bch_check_keys(struct btree *b, const char *fmt, ...)
 253 {
 254         va_list args;
 255         struct bkey *k, *p = NULL;
 256         struct btree_iter iter;
 257         const char *err;
 258
 259         for_each_key(b, k, &iter) {
 260                 if (!b->level) {
 261                         err = "Keys out of order";
 262                         if (p && bkey_cmp(&START_KEY(p), &START_KEY(k)) > 0)
 263                                 goto bug;
 264
 265                         if (bch_ptr_invalid(b, k))
 266                                 continue;
 267
 268                         err =  "Overlapping keys";
 269                         if (p && bkey_cmp(p, &START_KEY(k)) > 0)
 270                                 goto bug;
 271                 } else {
 272                         if (bch_ptr_bad(b, k))
 273                                 continue;
 274
 275                         err = "Duplicate keys";
 276                         if (p && !bkey_cmp(p, k))
 277                                 goto bug;
 278                 }
 279                 p = k;
 280         }
 281
 282         err = "Key larger than btree node key";
 283         if (p && bkey_cmp(p, &b->key) > 0)
 284                 goto bug;
 285
 286         return;
 287 bug:
 288         bch_dump_bucket(b);
 289
 290         va_start(args, fmt);
 291         vprintk(fmt, args);
 292         va_end(args);
 293
 294         panic("bcache error: %s:\n", err);
 295 }
 296
 297 void bch_btree_iter_next_check(struct btree_iter *iter)
 298 {
 299         struct bkey *k = iter->data->k, *next = bkey_next(k);
 300
 301         if (next < iter->data->end &&
 302             bkey_cmp(k, iter->b->level ? next : &START_KEY(next)) > 0) {
 303                 bch_dump_bucket(iter->b);
 304                 panic("Key skipped backwards\n");
 305         }
 306 }
 307
 308 #endif
 309
 310 #ifdef CONFIG_DEBUG_FS
 311
 312 /* XXX: cache set refcounting */
 313
 314 struct dump_iterator {
 315         char                    buf[PAGE_SIZE];
 316         size_t                  bytes;
 317         struct cache_set        *c;
 318         struct keybuf           keys;
 319 };
 320
 321 static bool dump_pred(struct keybuf *buf, struct bkey *k)
 322 {
 323         return true;
 324 }
 325
 326 static ssize_t bch_dump_read(struct file *file, char __user *buf,
 327                              size_t size, loff_t *ppos)
 328 {
 329         struct dump_iterator *i = file->private_data;
 330         ssize_t ret = 0;
 331         char kbuf[80];
 332
 333         while (size) {
 334                 struct keybuf_key *w;
 335                 unsigned bytes = min(i->bytes, size);
 336
 337                 int err = copy_to_user(buf, i->buf, bytes);
 338                 if (err)
 339                         return err;
 340
 341                 ret      += bytes;
 342                 buf      += bytes;
 343                 size     -= bytes;
 344                 i->bytes -= bytes;
 345                 memmove(i->buf, i->buf + bytes, i->bytes);
 346
 347                 if (i->bytes)
 348                         break;
 349
 350                 w = bch_keybuf_next_rescan(i->c, &i->keys, &MAX_KEY, dump_pred);
 351                 if (!w)
 352                         break;
 353
 354                 bch_bkey_to_text(kbuf, sizeof(kbuf), &w->key);
 355                 i->bytes = snprintf(i->buf, PAGE_SIZE, "%s\n", kbuf);
 356                 bch_keybuf_del(&i->keys, w);
 357         }
 358
 359         return ret;
 360 }
 361
 362 static int bch_dump_open(struct inode *inode, struct file *file)
 363 {
 364         struct cache_set *c = inode->i_private;
 365         struct dump_iterator *i;
 366
 367         i = kzalloc(sizeof(struct dump_iterator), GFP_KERNEL);
 368         if (!i)
 369                 return -ENOMEM;
 370
 371         file->private_data = i;
 372         i->c = c;
 373         bch_keybuf_init(&i->keys);
 374         i->keys.last_scanned = KEY(0, 0, 0);
 375
 376         return 0;
 377 }
 378
 379 static int bch_dump_release(struct inode *inode, struct file *file)
 380 {
 381         kfree(file->private_data);
 382         return 0;
 383 }
 384
 385 static const struct file_operations cache_set_debug_ops = {
 386         .owner          = THIS_MODULE,
 387         .open           = bch_dump_open,
 388         .read           = bch_dump_read,
 389         .release        = bch_dump_release
 390 };
 391
 392 void bch_debug_init_cache_set(struct cache_set *c)
 393 {
 394         if (!IS_ERR_OR_NULL(debug)) {
 395                 char name[50];
 396                 snprintf(name, 50, "bcache-%pU", c->sb.set_uuid);
 397
 398                 c->debug = debugfs_create_file(name, 0400, debug, c,
 399                                                &cache_set_debug_ops);
 400         }
 401 }
 402
 403 #endif
 404
 405 void bch_debug_exit(void)
 406 {
 407         if (!IS_ERR_OR_NULL(debug))
 408                 debugfs_remove_recursive(debug);
 409 }
 410
 411 int __init bch_debug_init(struct kobject *kobj)
 412 {
 413         int ret = 0;
 414
 415         debug = debugfs_create_dir("bcache", NULL);
 416         return ret;
 417 }