fs/btrfs/tests/extent-map-tests.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2017 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/types.h>
   7 #include "btrfs-tests.h"
   8 #include "../ctree.h"
   9
  10 static void free_extent_map_tree(struct extent_map_tree *em_tree)
  11 {
  12         struct extent_map *em;
  13         struct rb_node *node;
  14
  15         while (!RB_EMPTY_ROOT(&em_tree->map)) {
  16                 node = rb_first(&em_tree->map);
  17                 em = rb_entry(node, struct extent_map, rb_node);
  18                 remove_extent_mapping(em_tree, em);
  19
  20 #ifdef CONFIG_BTRFS_DEBUG
  21                 if (refcount_read(&em->refs) != 1) {
  22                         test_msg(
  23 "em leak: em (start 0x%llx len 0x%llx block_start 0x%llx block_len 0x%llx) refs %d\n",
  24                                  em->start, em->len, em->block_start,
  25                                  em->block_len, refcount_read(&em->refs));
  26
  27                         refcount_set(&em->refs, 1);
  28                 }
  29 #endif
  30                 free_extent_map(em);
  31         }
  32 }
  33
  34 /*
  35  * Test scenario:
  36  *
  37  * Suppose that no extent map has been loaded into memory yet, there is a file
  38  * extent [0, 16K), followed by another file extent [16K, 20K), two dio reads
  39  * are entering btrfs_get_extent() concurrently, t1 is reading [8K, 16K), t2 is
  40  * reading [0, 8K)
  41  *
  42  *     t1                            t2
  43  *  btrfs_get_extent()              btrfs_get_extent()
  44  *    -> lookup_extent_mapping()      ->lookup_extent_mapping()
  45  *    -> add_extent_mapping(0, 16K)
  46  *    -> return em
  47  *                                    ->add_extent_mapping(0, 16K)
  48  *                                    -> #handle -EEXIST
  49  */
  50 static void test_case_1(struct extent_map_tree *em_tree)
  51 {
  52         struct extent_map *em;
  53         u64 start = 0;
  54         u64 len = SZ_8K;
  55         int ret;
  56
  57         em = alloc_extent_map();
  58         if (!em)
  59                 /* Skip the test on error. */
  60                 return;
  61
  62         /* Add [0, 16K) */
  63         em->start = 0;
  64         em->len = SZ_16K;
  65         em->block_start = 0;
  66         em->block_len = SZ_16K;
  67         ret = add_extent_mapping(em_tree, em, 0);
  68         ASSERT(ret == 0);
  69         free_extent_map(em);
  70
  71         /* Add [16K, 20K) following [0, 16K)  */
  72         em = alloc_extent_map();
  73         if (!em)
  74                 goto out;
  75
  76         em->start = SZ_16K;
  77         em->len = SZ_4K;
  78         em->block_start = SZ_32K; /* avoid merging */
  79         em->block_len = SZ_4K;
  80         ret = add_extent_mapping(em_tree, em, 0);
  81         ASSERT(ret == 0);
  82         free_extent_map(em);
  83
  84         em = alloc_extent_map();
  85         if (!em)
  86                 goto out;
  87
  88         /* Add [0, 8K), should return [0, 16K) instead. */
  89         em->start = start;
  90         em->len = len;
  91         em->block_start = start;
  92         em->block_len = len;
  93         ret = btrfs_add_extent_mapping(em_tree, &em, em->start, em->len);
  94         if (ret)
  95                 test_msg("case1 [%llu %llu]: ret %d\n", start, start + len, ret);
  96         if (em &&
  97             (em->start != 0 || extent_map_end(em) != SZ_16K ||
  98              em->block_start != 0 || em->block_len != SZ_16K))
  99                 test_msg(
 100 "case1 [%llu %llu]: ret %d return a wrong em (start %llu len %llu block_start %llu block_len %llu\n",
 101                          start, start + len, ret, em->start, em->len,
 102                          em->block_start, em->block_len);
 103         free_extent_map(em);
 104 out:
 105         /* free memory */
 106         free_extent_map_tree(em_tree);
 107 }
 108
 109 /*
 110  * Test scenario:
 111  *
 112  * Reading the inline ending up with EEXIST, ie. read an inline
 113  * extent and discard page cache and read it again.
 114  */
 115 static void test_case_2(struct extent_map_tree *em_tree)
 116 {
 117         struct extent_map *em;
 118         int ret;
 119
 120         em = alloc_extent_map();
 121         if (!em)
 122                 /* Skip the test on error. */
 123                 return;
 124
 125         /* Add [0, 1K) */
 126         em->start = 0;
 127         em->len = SZ_1K;
 128         em->block_start = EXTENT_MAP_INLINE;
 129         em->block_len = (u64)-1;
 130         ret = add_extent_mapping(em_tree, em, 0);
 131         ASSERT(ret == 0);
 132         free_extent_map(em);
 133
 134         /* Add [4K, 4K) following [0, 1K)  */
 135         em = alloc_extent_map();
 136         if (!em)
 137                 goto out;
 138
 139         em->start = SZ_4K;
 140         em->len = SZ_4K;
 141         em->block_start = SZ_4K;
 142         em->block_len = SZ_4K;
 143         ret = add_extent_mapping(em_tree, em, 0);
 144         ASSERT(ret == 0);
 145         free_extent_map(em);
 146
 147         em = alloc_extent_map();
 148         if (!em)
 149                 goto out;
 150
 151         /* Add [0, 1K) */
 152         em->start = 0;
 153         em->len = SZ_1K;
 154         em->block_start = EXTENT_MAP_INLINE;
 155         em->block_len = (u64)-1;
 156         ret = btrfs_add_extent_mapping(em_tree, &em, em->start, em->len);
 157         if (ret)
 158                 test_msg("case2 [0 1K]: ret %d\n", ret);
 159         if (em &&
 160             (em->start != 0 || extent_map_end(em) != SZ_1K ||
 161              em->block_start != EXTENT_MAP_INLINE || em->block_len != (u64)-1))
 162                 test_msg(
 163 "case2 [0 1K]: ret %d return a wrong em (start %llu len %llu block_start %llu block_len %llu\n",
 164                          ret, em->start, em->len, em->block_start,
 165                          em->block_len);
 166         free_extent_map(em);
 167 out:
 168         /* free memory */
 169         free_extent_map_tree(em_tree);
 170 }
 171
 172 static void __test_case_3(struct extent_map_tree *em_tree, u64 start)
 173 {
 174         struct extent_map *em;
 175         u64 len = SZ_4K;
 176         int ret;
 177
 178         em = alloc_extent_map();
 179         if (!em)
 180                 /* Skip this test on error. */
 181                 return;
 182
 183         /* Add [4K, 8K) */
 184         em->start = SZ_4K;
 185         em->len = SZ_4K;
 186         em->block_start = SZ_4K;
 187         em->block_len = SZ_4K;
 188         ret = add_extent_mapping(em_tree, em, 0);
 189         ASSERT(ret == 0);
 190         free_extent_map(em);
 191
 192         em = alloc_extent_map();
 193         if (!em)
 194                 goto out;
 195
 196         /* Add [0, 16K) */
 197         em->start = 0;
 198         em->len = SZ_16K;
 199         em->block_start = 0;
 200         em->block_len = SZ_16K;
 201         ret = btrfs_add_extent_mapping(em_tree, &em, start, len);
 202         if (ret)
 203                 test_msg("case3 [0x%llx 0x%llx): ret %d\n",
 204                          start, start + len, ret);
 205         /*
 206          * Since bytes within em are contiguous, em->block_start is identical to
 207          * em->start.
 208          */
 209         if (em &&
 210             (start < em->start || start + len > extent_map_end(em) ||
 211              em->start != em->block_start || em->len != em->block_len))
 212                 test_msg(
 213 "case3 [0x%llx 0x%llx): ret %d em (start 0x%llx len 0x%llx block_start 0x%llx block_len 0x%llx)\n",
 214                          start, start + len, ret, em->start, em->len,
 215                          em->block_start, em->block_len);
 216         free_extent_map(em);
 217 out:
 218         /* free memory */
 219         free_extent_map_tree(em_tree);
 220 }
 221
 222 /*
 223  * Test scenario:
 224  *
 225  * Suppose that no extent map has been loaded into memory yet.
 226  * There is a file extent [0, 16K), two jobs are running concurrently
 227  * against it, t1 is buffered writing to [4K, 8K) and t2 is doing dio
 228  * read from [0, 4K) or [8K, 12K) or [12K, 16K).
 229  *
 230  * t1 goes ahead of t2 and adds em [4K, 8K) into tree.
 231  *
 232  *         t1                       t2
 233  *  cow_file_range()         btrfs_get_extent()
 234  *                            -> lookup_extent_mapping()
 235  *   -> add_extent_mapping()
 236  *                            -> add_extent_mapping()
 237  */
 238 static void test_case_3(struct extent_map_tree *em_tree)
 239 {
 240         __test_case_3(em_tree, 0);
 241         __test_case_3(em_tree, SZ_8K);
 242         __test_case_3(em_tree, (12 * 1024ULL));
 243 }
 244
 245 static void __test_case_4(struct extent_map_tree *em_tree, u64 start)
 246 {
 247         struct extent_map *em;
 248         u64 len = SZ_4K;
 249         int ret;
 250
 251         em = alloc_extent_map();
 252         if (!em)
 253                 /* Skip this test on error. */
 254                 return;
 255
 256         /* Add [0K, 8K) */
 257         em->start = 0;
 258         em->len = SZ_8K;
 259         em->block_start = 0;
 260         em->block_len = SZ_8K;
 261         ret = add_extent_mapping(em_tree, em, 0);
 262         ASSERT(ret == 0);
 263         free_extent_map(em);
 264
 265         em = alloc_extent_map();
 266         if (!em)
 267                 goto out;
 268
 269         /* Add [8K, 24K) */
 270         em->start = SZ_8K;
 271         em->len = 24 * 1024ULL;
 272         em->block_start = SZ_16K; /* avoid merging */
 273         em->block_len = 24 * 1024ULL;
 274         ret = add_extent_mapping(em_tree, em, 0);
 275         ASSERT(ret == 0);
 276         free_extent_map(em);
 277
 278         em = alloc_extent_map();
 279         if (!em)
 280                 goto out;
 281         /* Add [0K, 32K) */
 282         em->start = 0;
 283         em->len = SZ_32K;
 284         em->block_start = 0;
 285         em->block_len = SZ_32K;
 286         ret = btrfs_add_extent_mapping(em_tree, &em, start, len);
 287         if (ret)
 288                 test_msg("case4 [0x%llx 0x%llx): ret %d\n",
 289                          start, len, ret);
 290         if (em &&
 291             (start < em->start || start + len > extent_map_end(em)))
 292                 test_msg(
 293 "case4 [0x%llx 0x%llx): ret %d, added wrong em (start 0x%llx len 0x%llx block_start 0x%llx block_len 0x%llx)\n",
 294                          start, len, ret, em->start, em->len, em->block_start,
 295                          em->block_len);
 296         free_extent_map(em);
 297 out:
 298         /* free memory */
 299         free_extent_map_tree(em_tree);
 300 }
 301
 302 /*
 303  * Test scenario:
 304  *
 305  * Suppose that no extent map has been loaded into memory yet.
 306  * There is a file extent [0, 32K), two jobs are running concurrently
 307  * against it, t1 is doing dio write to [8K, 32K) and t2 is doing dio
 308  * read from [0, 4K) or [4K, 8K).
 309  *
 310  * t1 goes ahead of t2 and splits em [0, 32K) to em [0K, 8K) and [8K 32K).
 311  *
 312  *         t1                                t2
 313  *  btrfs_get_blocks_direct()          btrfs_get_blocks_direct()
 314  *   -> btrfs_get_extent()              -> btrfs_get_extent()
 315  *       -> lookup_extent_mapping()
 316  *       -> add_extent_mapping()            -> lookup_extent_mapping()
 317  *          # load [0, 32K)
 318  *   -> btrfs_new_extent_direct()
 319  *       -> btrfs_drop_extent_cache()
 320  *          # split [0, 32K)
 321  *       -> add_extent_mapping()
 322  *          # add [8K, 32K)
 323  *                                          -> add_extent_mapping()
 324  *                                             # handle -EEXIST when adding
 325  *                                             # [0, 32K)
 326  */
 327 static void test_case_4(struct extent_map_tree *em_tree)
 328 {
 329         __test_case_4(em_tree, 0);
 330         __test_case_4(em_tree, SZ_4K);
 331 }
 332
 333 int btrfs_test_extent_map(void)
 334 {
 335         struct extent_map_tree *em_tree;
 336
 337         test_msg("Running extent_map tests\n");
 338
 339         em_tree = kzalloc(sizeof(*em_tree), GFP_KERNEL);
 340         if (!em_tree)
 341                 /* Skip the test on error. */
 342                 return 0;
 343
 344         extent_map_tree_init(em_tree);
 345
 346         test_case_1(em_tree);
 347         test_case_2(em_tree);
 348         test_case_3(em_tree);
 349         test_case_4(em_tree);
 350
 351         kfree(em_tree);
 352         return 0;
 353 }