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_OFFSET(k), KEY_SIZE(k));
  57
  58         if (KEY_PTRS(k))
  59                 while (1) {
  60                         p("%llu:%llu gen %llu",
  61                           PTR_DEV(k, i), PTR_OFFSET(k, i), PTR_GEN(k, i));
  62
  63                         if (++i == KEY_PTRS(k))
  64                                 break;
  65
  66                         p(", ");
  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)
  82 {
  83         struct bkey *k, *next;
  84         unsigned j;
  85         char buf[80];
  86
  87         for (k = i->start; k < end(i); k = next) {
  88                 next = bkey_next(k);
  89
  90                 bch_bkey_to_text(buf, sizeof(buf), k);
  91                 printk(KERN_ERR "block %zu key %zi/%u: %s", index(i, b),
  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 < end(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         console_unlock();
 119 }
 120
 121 void bch_btree_verify(struct btree *b, struct bset *new)
 122 {
 123         struct btree *v = b->c->verify_data;
 124         struct closure cl;
 125         closure_init_stack(&cl);
 126
 127         if (!b->c->verify)
 128                 return;
 129
 130         closure_wait_event(&b->io.wait, &cl,
 131                            atomic_read(&b->io.cl.remaining) == -1);
 132
 133         mutex_lock(&b->c->verify_lock);
 134
 135         bkey_copy(&v->key, &b->key);
 136         v->written = 0;
 137         v->level = b->level;
 138
 139         bch_btree_node_read(v);
 140         closure_wait_event(&v->io.wait, &cl,
 141                            atomic_read(&b->io.cl.remaining) == -1);
 142
 143         if (new->keys != v->sets[0].data->keys ||
 144             memcmp(new->start,
 145                    v->sets[0].data->start,
 146                    (void *) end(new) - (void *) new->start)) {
 147                 unsigned i, j;
 148
 149                 console_lock();
 150
 151                 printk(KERN_ERR "*** original memory node:\n");
 152                 for (i = 0; i <= b->nsets; i++)
 153                         dump_bset(b, b->sets[i].data);
 154
 155                 printk(KERN_ERR "*** sorted memory node:\n");
 156                 dump_bset(b, new);
 157
 158                 printk(KERN_ERR "*** on disk node:\n");
 159                 dump_bset(v, v->sets[0].data);
 160
 161                 for (j = 0; j < new->keys; j++)
 162                         if (new->d[j] != v->sets[0].data->d[j])
 163                                 break;
 164
 165                 console_unlock();
 166                 panic("verify failed at %u\n", j);
 167         }
 168
 169         mutex_unlock(&b->c->verify_lock);
 170 }
 171
 172 void bch_data_verify(struct cached_dev *dc, struct bio *bio)
 173 {
 174         char name[BDEVNAME_SIZE];
 175         struct bio *check;
 176         struct bio_vec *bv;
 177         int i;
 178
 179         check = bio_clone(bio, GFP_NOIO);
 180         if (!check)
 181                 return;
 182
 183         if (bio_alloc_pages(check, GFP_NOIO))
 184                 goto out_put;
 185
 186         submit_bio_wait(READ_SYNC, check);
 187
 188         bio_for_each_segment(bv, bio, i) {
 189                 void *p1 = kmap_atomic(bv->bv_page);
 190                 void *p2 = page_address(check->bi_io_vec[i].bv_page);
 191
 192                 cache_set_err_on(memcmp(p1 + bv->bv_offset,
 193                                         p2 + bv->bv_offset,
 194                                         bv->bv_len),
 195                                  dc->disk.c,
 196                                  "verify failed at dev %s sector %llu",
 197                                  bdevname(dc->bdev, name),
 198                                  (uint64_t) bio->bi_sector);
 199
 200                 kunmap_atomic(p1);
 201         }
 202
 203         bio_for_each_segment_all(bv, check, i)
 204                 __free_page(bv->bv_page);
 205 out_put:
 206         bio_put(check);
 207 }
 208
 209 int __bch_count_data(struct btree *b)
 210 {
 211         unsigned ret = 0;
 212         struct btree_iter iter;
 213         struct bkey *k;
 214
 215         if (!b->level)
 216                 for_each_key(b, k, &iter)
 217                         ret += KEY_SIZE(k);
 218         return ret;
 219 }
 220
 221 void __bch_check_keys(struct btree *b, const char *fmt, ...)
 222 {
 223         va_list args;
 224         struct bkey *k, *p = NULL;
 225         struct btree_iter iter;
 226         const char *err;
 227
 228         for_each_key(b, k, &iter) {
 229                 if (!b->level) {
 230                         err = "Keys out of order";
 231                         if (p && bkey_cmp(&START_KEY(p), &START_KEY(k)) > 0)
 232                                 goto bug;
 233
 234                         if (bch_ptr_invalid(b, k))
 235                                 continue;
 236
 237                         err =  "Overlapping keys";
 238                         if (p && bkey_cmp(p, &START_KEY(k)) > 0)
 239                                 goto bug;
 240                 } else {
 241                         if (bch_ptr_bad(b, k))
 242                                 continue;
 243
 244                         err = "Duplicate keys";
 245                         if (p && !bkey_cmp(p, k))
 246                                 goto bug;
 247                 }
 248                 p = k;
 249         }
 250
 251         err = "Key larger than btree node key";
 252         if (p && bkey_cmp(p, &b->key) > 0)
 253                 goto bug;
 254
 255         return;
 256 bug:
 257         bch_dump_bucket(b);
 258
 259         va_start(args, fmt);
 260         vprintk(fmt, args);
 261         va_end(args);
 262
 263         panic("bcache error: %s:\n", err);
 264 }
 265
 266 void bch_btree_iter_next_check(struct btree_iter *iter)
 267 {
 268         struct bkey *k = iter->data->k, *next = bkey_next(k);
 269
 270         if (next < iter->data->end &&
 271             bkey_cmp(k, iter->b->level ? next : &START_KEY(next)) > 0) {
 272                 bch_dump_bucket(iter->b);
 273                 panic("Key skipped backwards\n");
 274         }
 275 }
 276
 277 #endif
 278
 279 #ifdef CONFIG_DEBUG_FS
 280
 281 /* XXX: cache set refcounting */
 282
 283 struct dump_iterator {
 284         char                    buf[PAGE_SIZE];
 285         size_t                  bytes;
 286         struct cache_set        *c;
 287         struct keybuf           keys;
 288 };
 289
 290 static bool dump_pred(struct keybuf *buf, struct bkey *k)
 291 {
 292         return true;
 293 }
 294
 295 static ssize_t bch_dump_read(struct file *file, char __user *buf,
 296                              size_t size, loff_t *ppos)
 297 {
 298         struct dump_iterator *i = file->private_data;
 299         ssize_t ret = 0;
 300         char kbuf[80];
 301
 302         while (size) {
 303                 struct keybuf_key *w;
 304                 unsigned bytes = min(i->bytes, size);
 305
 306                 int err = copy_to_user(buf, i->buf, bytes);
 307                 if (err)
 308                         return err;
 309
 310                 ret      += bytes;
 311                 buf      += bytes;
 312                 size     -= bytes;
 313                 i->bytes -= bytes;
 314                 memmove(i->buf, i->buf + bytes, i->bytes);
 315
 316                 if (i->bytes)
 317                         break;
 318
 319                 w = bch_keybuf_next_rescan(i->c, &i->keys, &MAX_KEY, dump_pred);
 320                 if (!w)
 321                         break;
 322
 323                 bch_bkey_to_text(kbuf, sizeof(kbuf), &w->key);
 324                 i->bytes = snprintf(i->buf, PAGE_SIZE, "%s\n", kbuf);
 325                 bch_keybuf_del(&i->keys, w);
 326         }
 327
 328         return ret;
 329 }
 330
 331 static int bch_dump_open(struct inode *inode, struct file *file)
 332 {
 333         struct cache_set *c = inode->i_private;
 334         struct dump_iterator *i;
 335
 336         i = kzalloc(sizeof(struct dump_iterator), GFP_KERNEL);
 337         if (!i)
 338                 return -ENOMEM;
 339
 340         file->private_data = i;
 341         i->c = c;
 342         bch_keybuf_init(&i->keys);
 343         i->keys.last_scanned = KEY(0, 0, 0);
 344
 345         return 0;
 346 }
 347
 348 static int bch_dump_release(struct inode *inode, struct file *file)
 349 {
 350         kfree(file->private_data);
 351         return 0;
 352 }
 353
 354 static const struct file_operations cache_set_debug_ops = {
 355         .owner          = THIS_MODULE,
 356         .open           = bch_dump_open,
 357         .read           = bch_dump_read,
 358         .release        = bch_dump_release
 359 };
 360
 361 void bch_debug_init_cache_set(struct cache_set *c)
 362 {
 363         if (!IS_ERR_OR_NULL(debug)) {
 364                 char name[50];
 365                 snprintf(name, 50, "bcache-%pU", c->sb.set_uuid);
 366
 367                 c->debug = debugfs_create_file(name, 0400, debug, c,
 368                                                &cache_set_debug_ops);
 369         }
 370 }
 371
 372 #endif
 373
 374 void bch_debug_exit(void)
 375 {
 376         if (!IS_ERR_OR_NULL(debug))
 377                 debugfs_remove_recursive(debug);
 378 }
 379
 380 int __init bch_debug_init(struct kobject *kobj)
 381 {
 382         int ret = 0;
 383
 384         debug = debugfs_create_dir("bcache", NULL);
 385         return ret;
 386 }