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 %u key %zi/%u: %s", bset_block_offset(b, i),
  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         down(&b->io_mutex);
 131         mutex_lock(&b->c->verify_lock);
 132
 133         bkey_copy(&v->key, &b->key);
 134         v->written = 0;
 135         v->level = b->level;
 136
 137         bch_btree_node_read(v);
 138
 139         if (new->keys != v->sets[0].data->keys ||
 140             memcmp(new->start,
 141                    v->sets[0].data->start,
 142                    (void *) end(new) - (void *) new->start)) {
 143                 unsigned i, j;
 144
 145                 console_lock();
 146
 147                 printk(KERN_ERR "*** original memory node:\n");
 148                 for (i = 0; i <= b->nsets; i++)
 149                         dump_bset(b, b->sets[i].data);
 150
 151                 printk(KERN_ERR "*** sorted memory node:\n");
 152                 dump_bset(b, new);
 153
 154                 printk(KERN_ERR "*** on disk node:\n");
 155                 dump_bset(v, v->sets[0].data);
 156
 157                 for (j = 0; j < new->keys; j++)
 158                         if (new->d[j] != v->sets[0].data->d[j])
 159                                 break;
 160
 161                 console_unlock();
 162                 panic("verify failed at %u\n", j);
 163         }
 164
 165         mutex_unlock(&b->c->verify_lock);
 166         up(&b->io_mutex);
 167 }
 168
 169 void bch_data_verify(struct cached_dev *dc, struct bio *bio)
 170 {
 171         char name[BDEVNAME_SIZE];
 172         struct bio *check;
 173         struct bio_vec bv, *bv2;
 174         struct bvec_iter iter;
 175         int i;
 176
 177         check = bio_clone(bio, GFP_NOIO);
 178         if (!check)
 179                 return;
 180
 181         if (bio_alloc_pages(check, GFP_NOIO))
 182                 goto out_put;
 183
 184         submit_bio_wait(READ_SYNC, check);
 185
 186         bio_for_each_segment(bv, bio, iter) {
 187                 void *p1 = kmap_atomic(bv.bv_page);
 188                 void *p2 = page_address(check->bi_io_vec[iter.bi_idx].bv_page);
 189
 190                 cache_set_err_on(memcmp(p1 + bv.bv_offset,
 191                                         p2 + bv.bv_offset,
 192                                         bv.bv_len),
 193                                  dc->disk.c,
 194                                  "verify failed at dev %s sector %llu",
 195                                  bdevname(dc->bdev, name),
 196                                  (uint64_t) bio->bi_iter.bi_sector);
 197
 198                 kunmap_atomic(p1);
 199         }
 200
 201         bio_for_each_segment_all(bv2, check, i)
 202                 __free_page(bv2->bv_page);
 203 out_put:
 204         bio_put(check);
 205 }
 206
 207 int __bch_count_data(struct btree *b)
 208 {
 209         unsigned ret = 0;
 210         struct btree_iter iter;
 211         struct bkey *k;
 212
 213         if (!b->level)
 214                 for_each_key(b, k, &iter)
 215                         ret += KEY_SIZE(k);
 216         return ret;
 217 }
 218
 219 void __bch_check_keys(struct btree *b, const char *fmt, ...)
 220 {
 221         va_list args;
 222         struct bkey *k, *p = NULL;
 223         struct btree_iter iter;
 224         const char *err;
 225
 226         for_each_key(b, k, &iter) {
 227                 if (!b->level) {
 228                         err = "Keys out of order";
 229                         if (p && bkey_cmp(&START_KEY(p), &START_KEY(k)) > 0)
 230                                 goto bug;
 231
 232                         if (bch_ptr_invalid(b, k))
 233                                 continue;
 234
 235                         err =  "Overlapping keys";
 236                         if (p && bkey_cmp(p, &START_KEY(k)) > 0)
 237                                 goto bug;
 238                 } else {
 239                         if (bch_ptr_bad(b, k))
 240                                 continue;
 241
 242                         err = "Duplicate keys";
 243                         if (p && !bkey_cmp(p, k))
 244                                 goto bug;
 245                 }
 246                 p = k;
 247         }
 248
 249         err = "Key larger than btree node key";
 250         if (p && bkey_cmp(p, &b->key) > 0)
 251                 goto bug;
 252
 253         return;
 254 bug:
 255         bch_dump_bucket(b);
 256
 257         va_start(args, fmt);
 258         vprintk(fmt, args);
 259         va_end(args);
 260
 261         panic("bcache error: %s:\n", err);
 262 }
 263
 264 void bch_btree_iter_next_check(struct btree_iter *iter)
 265 {
 266         struct bkey *k = iter->data->k, *next = bkey_next(k);
 267
 268         if (next < iter->data->end &&
 269             bkey_cmp(k, iter->b->level ? next : &START_KEY(next)) > 0) {
 270                 bch_dump_bucket(iter->b);
 271                 panic("Key skipped backwards\n");
 272         }
 273 }
 274
 275 #endif
 276
 277 #ifdef CONFIG_DEBUG_FS
 278
 279 /* XXX: cache set refcounting */
 280
 281 struct dump_iterator {
 282         char                    buf[PAGE_SIZE];
 283         size_t                  bytes;
 284         struct cache_set        *c;
 285         struct keybuf           keys;
 286 };
 287
 288 static bool dump_pred(struct keybuf *buf, struct bkey *k)
 289 {
 290         return true;
 291 }
 292
 293 static ssize_t bch_dump_read(struct file *file, char __user *buf,
 294                              size_t size, loff_t *ppos)
 295 {
 296         struct dump_iterator *i = file->private_data;
 297         ssize_t ret = 0;
 298         char kbuf[80];
 299
 300         while (size) {
 301                 struct keybuf_key *w;
 302                 unsigned bytes = min(i->bytes, size);
 303
 304                 int err = copy_to_user(buf, i->buf, bytes);
 305                 if (err)
 306                         return err;
 307
 308                 ret      += bytes;
 309                 buf      += bytes;
 310                 size     -= bytes;
 311                 i->bytes -= bytes;
 312                 memmove(i->buf, i->buf + bytes, i->bytes);
 313
 314                 if (i->bytes)
 315                         break;
 316
 317                 w = bch_keybuf_next_rescan(i->c, &i->keys, &MAX_KEY, dump_pred);
 318                 if (!w)
 319                         break;
 320
 321                 bch_bkey_to_text(kbuf, sizeof(kbuf), &w->key);
 322                 i->bytes = snprintf(i->buf, PAGE_SIZE, "%s\n", kbuf);
 323                 bch_keybuf_del(&i->keys, w);
 324         }
 325
 326         return ret;
 327 }
 328
 329 static int bch_dump_open(struct inode *inode, struct file *file)
 330 {
 331         struct cache_set *c = inode->i_private;
 332         struct dump_iterator *i;
 333
 334         i = kzalloc(sizeof(struct dump_iterator), GFP_KERNEL);
 335         if (!i)
 336                 return -ENOMEM;
 337
 338         file->private_data = i;
 339         i->c = c;
 340         bch_keybuf_init(&i->keys);
 341         i->keys.last_scanned = KEY(0, 0, 0);
 342
 343         return 0;
 344 }
 345
 346 static int bch_dump_release(struct inode *inode, struct file *file)
 347 {
 348         kfree(file->private_data);
 349         return 0;
 350 }
 351
 352 static const struct file_operations cache_set_debug_ops = {
 353         .owner          = THIS_MODULE,
 354         .open           = bch_dump_open,
 355         .read           = bch_dump_read,
 356         .release        = bch_dump_release
 357 };
 358
 359 void bch_debug_init_cache_set(struct cache_set *c)
 360 {
 361         if (!IS_ERR_OR_NULL(debug)) {
 362                 char name[50];
 363                 snprintf(name, 50, "bcache-%pU", c->sb.set_uuid);
 364
 365                 c->debug = debugfs_create_file(name, 0400, debug, c,
 366                                                &cache_set_debug_ops);
 367         }
 368 }
 369
 370 #endif
 371
 372 void bch_debug_exit(void)
 373 {
 374         if (!IS_ERR_OR_NULL(debug))
 375                 debugfs_remove_recursive(debug);
 376 }
 377
 378 int __init bch_debug_init(struct kobject *kobj)
 379 {
 380         int ret = 0;
 381
 382         debug = debugfs_create_dir("bcache", NULL);
 383         return ret;
 384 }