tests/qemu-iotests/261

   1 #!/usr/bin/env bash
   2 #
   3 # Test case for qcow2's handling of extra data in snapshot table entries
   4 # (and more generally, how certain cases of broken snapshot tables are
   5 # handled)
   6 #
   7 # Copyright (C) 2019 Red Hat, Inc.
   8 #
   9 # This program is free software; you can redistribute it and/or modify
  10 # it under the terms of the GNU General Public License as published by
  11 # the Free Software Foundation; either version 2 of the License, or
  12 # (at your option) any later version.
  13 #
  14 # This program is distributed in the hope that it will be useful,
  15 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 # GNU General Public License for more details.
  18 #
  19 # You should have received a copy of the GNU General Public License
  20 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 #
  22
  23 # creator
  24 owner=mreitz@redhat.com
  25
  26 seq=$(basename $0)
  27 echo "QA output created by $seq"
  28
  29 status=1        # failure is the default!
  30
  31 _cleanup()
  32 {
  33     _cleanup_test_img
  34     rm -f "$TEST_IMG".v{2,3}.orig
  35     rm -f "$TEST_DIR"/sn{0,1,2}{,-pre,-extra,-post}
  36 }
  37 trap "_cleanup; exit \$status" 0 1 2 3 15
  38
  39 # get standard environment, filters and checks
  40 . ./common.rc
  41 . ./common.filter
  42
  43 # This tests qcow2-specific low-level functionality
  44 _supported_fmt qcow2
  45 _supported_proto file
  46 _supported_os Linux
  47 # (1) We create a v2 image that supports nothing but refcount_bits=16
  48 # (2) We do some refcount management on our own which expects
  49 #     refcount_bits=16
  50 # As for data files, they do not support snapshots at all.
  51 _unsupported_imgopts 'refcount_bits=\([^1]\|.\([^6]\|$\)\)' data_file
  52
  53 # Parameters:
  54 #   $1: image filename
  55 #   $2: snapshot table entry offset in the image
  56 snapshot_table_entry_size()
  57 {
  58     id_len=$(peek_file_be "$1" $(($2 + 12)) 2)
  59     name_len=$(peek_file_be "$1" $(($2 + 14)) 2)
  60     extra_len=$(peek_file_be "$1" $(($2 + 36)) 4)
  61
  62     full_len=$((40 + extra_len + id_len + name_len))
  63     echo $(((full_len + 7) / 8 * 8))
  64 }
  65
  66 # Parameter:
  67 #   $1: image filename
  68 print_snapshot_table()
  69 {
  70     nb_entries=$(peek_file_be "$1" 60 4)
  71     offset=$(peek_file_be "$1" 64 8)
  72
  73     echo "Snapshots in $1:" | _filter_testdir | _filter_imgfmt
  74
  75     for ((i = 0; i < nb_entries; i++)); do
  76         id_len=$(peek_file_be "$1" $((offset + 12)) 2)
  77         name_len=$(peek_file_be "$1" $((offset + 14)) 2)
  78         extra_len=$(peek_file_be "$1" $((offset + 36)) 4)
  79
  80         extra_ofs=$((offset + 40))
  81         id_ofs=$((extra_ofs + extra_len))
  82         name_ofs=$((id_ofs + id_len))
  83
  84         echo "  [$i]"
  85         echo "    ID: $(peek_file_raw "$1" $id_ofs $id_len)"
  86         echo "    Name: $(peek_file_raw "$1" $name_ofs $name_len)"
  87         echo "    Extra data size: $extra_len"
  88         if [ $extra_len -ge 8 ]; then
  89             echo "    VM state size: $(peek_file_be "$1" $extra_ofs 8)"
  90         fi
  91         if [ $extra_len -ge 16 ]; then
  92             echo "    Disk size: $(peek_file_be "$1" $((extra_ofs + 8)) 8)"
  93         fi
  94         if [ $extra_len -gt 16 ]; then
  95             echo '    Unknown extra data:' \
  96                 "$(peek_file_raw "$1" $((extra_ofs + 16)) $((extra_len - 16)) \
  97                    | tr -d '\0')"
  98         fi
  99
 100         offset=$((offset + $(snapshot_table_entry_size "$1" $offset)))
 101     done
 102 }
 103
 104 # Mark clusters as allocated; works only in refblock 0 (i.e. before
 105 # cluster #32768).
 106 # Parameters:
 107 #   $1: Start offset of what to allocate
 108 #   $2: End offset (exclusive)
 109 refblock0_allocate()
 110 {
 111     reftable_ofs=$(peek_file_be "$TEST_IMG" 48 8)
 112     refblock_ofs=$(peek_file_be "$TEST_IMG" $reftable_ofs 8)
 113
 114     cluster=$(($1 / 65536))
 115     ecluster=$((($2 + 65535) / 65536))
 116
 117     while [ $cluster -lt $ecluster ]; do
 118         if [ $cluster -ge 32768 ]; then
 119             echo "*** Abort: Cluster $cluster exceeds refblock 0 ***"
 120             exit 1
 121         fi
 122         poke_file "$TEST_IMG" $((refblock_ofs + cluster * 2)) '\x00\x01'
 123         cluster=$((cluster + 1))
 124     done
 125 }
 126
 127
 128 echo
 129 echo '=== Create v2 template ==='
 130 echo
 131
 132 # Create v2 image with a snapshot table with three entries:
 133 # [0]: No extra data (valid with v2, not valid with v3)
 134 # [1]: Has extra data unknown to qemu
 135 # [2]: Has the 64-bit VM state size, but not the disk size (again,
 136 #      valid with v2, not valid with v3)
 137
 138 TEST_IMG="$TEST_IMG.v2.orig" IMGOPTS='compat=0.10' _make_test_img 64M
 139 $QEMU_IMG snapshot -c sn0 "$TEST_IMG.v2.orig"
 140 $QEMU_IMG snapshot -c sn1 "$TEST_IMG.v2.orig"
 141 $QEMU_IMG snapshot -c sn2 "$TEST_IMG.v2.orig"
 142
 143 # Copy out all existing snapshot table entries
 144 sn_table_ofs=$(peek_file_be "$TEST_IMG.v2.orig" 64 8)
 145
 146 # ofs: Snapshot table entry offset
 147 # eds: Extra data size
 148 # ids: Name + ID size
 149 # len: Total entry length
 150 sn0_ofs=$sn_table_ofs
 151 sn0_eds=$(peek_file_be "$TEST_IMG.v2.orig" $((sn0_ofs + 36)) 4)
 152 sn0_ids=$(($(peek_file_be "$TEST_IMG.v2.orig" $((sn0_ofs + 12)) 2) +
 153            $(peek_file_be "$TEST_IMG.v2.orig" $((sn0_ofs + 14)) 2)))
 154 sn0_len=$(snapshot_table_entry_size "$TEST_IMG.v2.orig" $sn0_ofs)
 155 sn1_ofs=$((sn0_ofs + sn0_len))
 156 sn1_eds=$(peek_file_be "$TEST_IMG.v2.orig" $((sn1_ofs + 36)) 4)
 157 sn1_ids=$(($(peek_file_be "$TEST_IMG.v2.orig" $((sn1_ofs + 12)) 2) +
 158            $(peek_file_be "$TEST_IMG.v2.orig" $((sn1_ofs + 14)) 2)))
 159 sn1_len=$(snapshot_table_entry_size "$TEST_IMG.v2.orig" $sn1_ofs)
 160 sn2_ofs=$((sn1_ofs + sn1_len))
 161 sn2_eds=$(peek_file_be "$TEST_IMG.v2.orig" $((sn2_ofs + 36)) 4)
 162 sn2_ids=$(($(peek_file_be "$TEST_IMG.v2.orig" $((sn2_ofs + 12)) 2) +
 163            $(peek_file_be "$TEST_IMG.v2.orig" $((sn2_ofs + 14)) 2)))
 164 sn2_len=$(snapshot_table_entry_size "$TEST_IMG.v2.orig" $sn2_ofs)
 165
 166 # Data before extra data
 167 dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn0-pre" bs=1 skip=$sn0_ofs count=40 \
 168     &> /dev/null
 169 dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn1-pre" bs=1 skip=$sn1_ofs count=40 \
 170     &> /dev/null
 171 dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn2-pre" bs=1 skip=$sn2_ofs count=40 \
 172     &> /dev/null
 173
 174 # Extra data
 175 dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn0-extra" bs=1 \
 176     skip=$((sn0_ofs + 40)) count=$sn0_eds &> /dev/null
 177 dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn1-extra" bs=1 \
 178     skip=$((sn1_ofs + 40)) count=$sn1_eds &> /dev/null
 179 dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn2-extra" bs=1 \
 180     skip=$((sn2_ofs + 40)) count=$sn2_eds &> /dev/null
 181
 182 # Data after extra data
 183 dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn0-post" bs=1 \
 184     skip=$((sn0_ofs + 40 + sn0_eds)) count=$sn0_ids \
 185     &> /dev/null
 186 dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn1-post" bs=1 \
 187     skip=$((sn1_ofs + 40 + sn1_eds)) count=$sn1_ids \
 188     &> /dev/null
 189 dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn2-post" bs=1 \
 190     skip=$((sn2_ofs + 40 + sn2_eds)) count=$sn2_ids \
 191     &> /dev/null
 192
 193 # Amend them, one by one
 194 # Set sn0's extra data size to 0
 195 poke_file "$TEST_DIR/sn0-pre" 36 '\x00\x00\x00\x00'
 196 truncate -s 0 "$TEST_DIR/sn0-extra"
 197 # Grow sn0-post to pad
 198 truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn0-pre") - 40)) \
 199     "$TEST_DIR/sn0-post"
 200
 201 # Set sn1's extra data size to 42
 202 poke_file "$TEST_DIR/sn1-pre" 36 '\x00\x00\x00\x2a'
 203 truncate -s 42 "$TEST_DIR/sn1-extra"
 204 poke_file "$TEST_DIR/sn1-extra" 16 'very important data'
 205 # Grow sn1-post to pad
 206 truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn1-pre") - 82)) \
 207     "$TEST_DIR/sn1-post"
 208
 209 # Set sn2's extra data size to 8
 210 poke_file "$TEST_DIR/sn2-pre" 36 '\x00\x00\x00\x08'
 211 truncate -s 8 "$TEST_DIR/sn2-extra"
 212 # Grow sn2-post to pad
 213 truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn2-pre") - 48)) \
 214     "$TEST_DIR/sn2-post"
 215
 216 # Construct snapshot table
 217 cat "$TEST_DIR"/sn0-{pre,extra,post} \
 218     "$TEST_DIR"/sn1-{pre,extra,post} \
 219     "$TEST_DIR"/sn2-{pre,extra,post} \
 220     | dd of="$TEST_IMG.v2.orig" bs=1 seek=$sn_table_ofs conv=notrunc \
 221           &> /dev/null
 222
 223 # Done!
 224 TEST_IMG="$TEST_IMG.v2.orig" _check_test_img
 225 print_snapshot_table "$TEST_IMG.v2.orig"
 226
 227 echo
 228 echo '=== Upgrade to v3 ==='
 229 echo
 230
 231 cp "$TEST_IMG.v2.orig" "$TEST_IMG.v3.orig"
 232 $QEMU_IMG amend -o compat=1.1 "$TEST_IMG.v3.orig"
 233 TEST_IMG="$TEST_IMG.v3.orig" _check_test_img
 234 print_snapshot_table "$TEST_IMG.v3.orig"
 235
 236 echo
 237 echo '=== Repair botched v3 ==='
 238 echo
 239
 240 # Force the v2 file to be v3.  v3 requires each snapshot table entry
 241 # to have at least 16 bytes of extra data, so it will not comply to
 242 # the qcow2 v3 specification; but we can fix that.
 243 cp "$TEST_IMG.v2.orig" "$TEST_IMG"
 244
 245 # Set version
 246 poke_file "$TEST_IMG" 4 '\x00\x00\x00\x03'
 247 # Increase header length (necessary for v3)
 248 poke_file "$TEST_IMG" 100 '\x00\x00\x00\x68'
 249 # Set refcount order (necessary for v3)
 250 poke_file "$TEST_IMG" 96 '\x00\x00\x00\x04'
 251
 252 _check_test_img -r all
 253 print_snapshot_table "$TEST_IMG"
 254
 255
 256 # From now on, just test the qcow2 version we are supposed to test.
 257 # (v3 by default, v2 by choice through $IMGOPTS.)
 258 # That works because we always write all known extra data when
 259 # updating the snapshot table, independent of the version.
 260
 261 if echo "$IMGOPTS" | grep -q 'compat=\(0\.10\|v2\)' 2> /dev/null; then
 262     subver=v2
 263 else
 264     subver=v3
 265 fi
 266
 267 echo
 268 echo '=== Add new snapshot ==='
 269 echo
 270
 271 cp "$TEST_IMG.$subver.orig" "$TEST_IMG"
 272 $QEMU_IMG snapshot -c sn3 "$TEST_IMG"
 273 _check_test_img
 274 print_snapshot_table "$TEST_IMG"
 275
 276 echo
 277 echo '=== Remove different snapshots ==='
 278
 279 for sn in sn0 sn1 sn2; do
 280     echo
 281     echo "--- $sn ---"
 282
 283     cp "$TEST_IMG.$subver.orig" "$TEST_IMG"
 284     $QEMU_IMG snapshot -d $sn "$TEST_IMG"
 285     _check_test_img
 286     print_snapshot_table "$TEST_IMG"
 287 done
 288
 289 echo
 290 echo '=== Reject too much unknown extra data ==='
 291 echo
 292
 293 cp "$TEST_IMG.$subver.orig" "$TEST_IMG"
 294 $QEMU_IMG snapshot -c sn3 "$TEST_IMG"
 295
 296 sn_table_ofs=$(peek_file_be "$TEST_IMG" 64 8)
 297 sn0_ofs=$sn_table_ofs
 298 sn1_ofs=$((sn0_ofs + $(snapshot_table_entry_size "$TEST_IMG" $sn0_ofs)))
 299 sn2_ofs=$((sn1_ofs + $(snapshot_table_entry_size "$TEST_IMG" $sn1_ofs)))
 300 sn3_ofs=$((sn2_ofs + $(snapshot_table_entry_size "$TEST_IMG" $sn2_ofs)))
 301
 302 # 64 kB of extra data should be rejected
 303 # (Note that this also induces a refcount error, because it spills
 304 # over to the next cluster.  That's a good way to test that we can
 305 # handle simultaneous snapshot table and refcount errors.)
 306 poke_file "$TEST_IMG" $((sn3_ofs + 36)) '\x00\x01\x00\x00'
 307
 308 # Print error
 309 _img_info
 310 echo
 311 _check_test_img
 312 echo
 313
 314 # Should be repairable
 315 _check_test_img -r all
 316
 317 echo
 318 echo '=== Snapshot table too big ==='
 319 echo
 320
 321 sn_table_ofs=$(peek_file_be "$TEST_IMG.v3.orig" 64 8)
 322
 323 # Fill a snapshot with 1 kB of extra data, a 65535-char ID, and a
 324 # 65535-char name, and repeat it as many times as necessary to fill
 325 # 64 MB (the maximum supported by qemu)
 326
 327 touch "$TEST_DIR/sn0"
 328
 329 # Full size (fixed + extra + ID + name + padding)
 330 sn_size=$((40 + 1024 + 65535 + 65535 + 2))
 331
 332 # We only need the fixed part, though.
 333 truncate -s 40 "$TEST_DIR/sn0"
 334
 335 # 65535-char ID string
 336 poke_file "$TEST_DIR/sn0" 12 '\xff\xff'
 337 # 65535-char name
 338 poke_file "$TEST_DIR/sn0" 14 '\xff\xff'
 339 # 1 kB of extra data
 340 poke_file "$TEST_DIR/sn0" 36 '\x00\x00\x04\x00'
 341
 342 # Create test image
 343 _make_test_img 64M
 344
 345 # Hook up snapshot table somewhere safe (at 1 MB)
 346 poke_file "$TEST_IMG" 64 '\x00\x00\x00\x00\x00\x10\x00\x00'
 347
 348 offset=1048576
 349 size_written=0
 350 sn_count=0
 351 while [ $size_written -le $((64 * 1048576)) ]; do
 352     dd if="$TEST_DIR/sn0" of="$TEST_IMG" bs=1 seek=$offset conv=notrunc \
 353         &> /dev/null
 354     offset=$((offset + sn_size))
 355     size_written=$((size_written + sn_size))
 356     sn_count=$((sn_count + 1))
 357 done
 358 truncate -s "$offset" "$TEST_IMG"
 359
 360 # Give the last snapshot (the one to be removed) an L1 table so we can
 361 # see how that is handled when repairing the image
 362 # (Put it two clusters before 1 MB, and one L2 table one cluster
 363 # before 1 MB)
 364 poke_file "$TEST_IMG" $((offset - sn_size + 0)) \
 365     '\x00\x00\x00\x00\x00\x0e\x00\x00'
 366 poke_file "$TEST_IMG" $((offset - sn_size + 8)) \
 367     '\x00\x00\x00\x01'
 368
 369 # Hook up the L2 table
 370 poke_file "$TEST_IMG" $((1048576 - 2 * 65536)) \
 371     '\x80\x00\x00\x00\x00\x0f\x00\x00'
 372
 373 # Make sure all of the clusters we just hooked up are allocated:
 374 # - The snapshot table
 375 # - The last snapshot's L1 and L2 table
 376 refblock0_allocate $((1048576 - 2 * 65536)) $offset
 377
 378 poke_file "$TEST_IMG" 60 \
 379     "$(printf '%08x' $sn_count | sed -e 's/\(..\)/\\x\1/g')"
 380
 381 # Print error
 382 _img_info
 383 echo
 384 _check_test_img
 385 echo
 386
 387 # Should be repairable
 388 _check_test_img -r all
 389
 390 echo
 391 echo "$((sn_count - 1)) snapshots should remain:"
 392 echo "  qemu-img info reports $(_img_info | grep -c '^ \{34\}') snapshots"
 393 echo "  Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots"
 394
 395 echo
 396 echo '=== Snapshot table too big with one entry with too much extra data ==='
 397 echo
 398
 399 # For this test, we reuse the image from the previous case, which has
 400 # a snapshot table that is right at the limit.
 401 # Our layout looks like this:
 402 # - (a number of snapshot table entries)
 403 # - One snapshot with $extra_data_size extra data
 404 # - One normal snapshot that breaks the 64 MB boundary
 405 # - One normal snapshot beyond the 64 MB boundary
 406 #
 407 # $extra_data_size is calculated so that simply by virtue of it
 408 # decreasing to 1 kB, the penultimate snapshot will fit into 64 MB
 409 # limit again.  The final snapshot will always be beyond the limit, so
 410 # that we can see that the repair algorithm does still determine the
 411 # limit to be somewhere, even when truncating one snapshot's extra
 412 # data.
 413
 414 # The last case has removed the last snapshot, so calculate
 415 # $old_offset to get the current image's real length
 416 old_offset=$((offset - sn_size))
 417
 418 # The layout from the previous test had one snapshot beyond the 64 MB
 419 # limit; we want the same (after the oversized extra data has been
 420 # truncated to 1 kB), so we drop the last three snapshots and
 421 # construct them from scratch.
 422 offset=$((offset - 3 * sn_size))
 423 sn_count=$((sn_count - 3))
 424
 425 # Assuming we had already written one of the three snapshots
 426 # (necessary so we can calculate $extra_data_size next).
 427 size_written=$((size_written - 2 * sn_size))
 428
 429 # Increase the extra data size so we go past the limit
 430 # (The -1024 comes from the 1 kB of extra data we already have)
 431 extra_data_size=$((64 * 1048576 + 8 - sn_size - (size_written - 1024)))
 432
 433 poke_file "$TEST_IMG" $((offset + 36)) \
 434     "$(printf '%08x' $extra_data_size | sed -e 's/\(..\)/\\x\1/g')"
 435
 436 offset=$((offset + sn_size - 1024 + extra_data_size))
 437 size_written=$((size_written - 1024 + extra_data_size))
 438 sn_count=$((sn_count + 1))
 439
 440 # Write the two normal snapshots
 441 for ((i = 0; i < 2; i++)); do
 442     dd if="$TEST_DIR/sn0" of="$TEST_IMG" bs=1 seek=$offset conv=notrunc \
 443         &> /dev/null
 444     offset=$((offset + sn_size))
 445     size_written=$((size_written + sn_size))
 446     sn_count=$((sn_count + 1))
 447
 448     if [ $i = 0 ]; then
 449         # Check that the penultimate snapshot is beyond the 64 MB limit
 450         echo "Snapshot table size should equal $((64 * 1048576 + 8)):" \
 451             $size_written
 452         echo
 453     fi
 454 done
 455
 456 truncate -s $offset "$TEST_IMG"
 457 refblock0_allocate $old_offset $offset
 458
 459 poke_file "$TEST_IMG" 60 \
 460     "$(printf '%08x' $sn_count | sed -e 's/\(..\)/\\x\1/g')"
 461
 462 # Print error
 463 _img_info
 464 echo
 465 _check_test_img
 466 echo
 467
 468 # Just truncating the extra data should be sufficient to shorten the
 469 # snapshot table so only one snapshot exceeds the extra size
 470 _check_test_img -r all
 471
 472 echo
 473 echo '=== Too many snapshots ==='
 474 echo
 475
 476 # Create a v2 image, for speeds' sake: All-zero snapshot table entries
 477 # are only valid in v2.
 478 IMGOPTS='compat=0.10' _make_test_img 64M
 479
 480 # Hook up snapshot table somewhere safe (at 1 MB)
 481 poke_file "$TEST_IMG" 64 '\x00\x00\x00\x00\x00\x10\x00\x00'
 482 # "Create" more than 65536 snapshots (twice that many here)
 483 poke_file "$TEST_IMG" 60 '\x00\x02\x00\x00'
 484
 485 # 40-byte all-zero snapshot table entries are valid snapshots, but
 486 # only in v2 (v3 needs 16 bytes of extra data, so we would have to
 487 # write 131072x '\x10').
 488 truncate -s $((1048576 + 40 * 131072)) "$TEST_IMG"
 489
 490 # But let us give one of the snapshots to be removed an L1 table so
 491 # we can see how that is handled when repairing the image.
 492 # (Put it two clusters before 1 MB, and one L2 table one cluster
 493 # before 1 MB)
 494 poke_file "$TEST_IMG" $((1048576 + 40 * 65536 + 0)) \
 495     '\x00\x00\x00\x00\x00\x0e\x00\x00'
 496 poke_file "$TEST_IMG" $((1048576 + 40 * 65536 + 8)) \
 497     '\x00\x00\x00\x01'
 498
 499 # Hook up the L2 table
 500 poke_file "$TEST_IMG" $((1048576 - 2 * 65536)) \
 501     '\x80\x00\x00\x00\x00\x0f\x00\x00'
 502
 503 # Make sure all of the clusters we just hooked up are allocated:
 504 # - The snapshot table
 505 # - The last snapshot's L1 and L2 table
 506 refblock0_allocate $((1048576 - 2 * 65536)) $((1048576 + 40 * 131072))
 507
 508 # Print error
 509 _img_info
 510 echo
 511 _check_test_img
 512 echo
 513
 514 # Should be repairable
 515 _check_test_img -r all
 516
 517 echo
 518 echo '65536 snapshots should remain:'
 519 echo "  qemu-img info reports $(_img_info | grep -c '^ \{34\}') snapshots"
 520 echo "  Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots"
 521
 522 # success, all done
 523 echo "*** done"
 524 status=0