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 24owner=mreitz@redhat.com 25 26seq=$(basename $0) 27echo "QA output created by $seq" 28 29status=1 # failure is the default! 30 31_cleanup() 32{ 33 _cleanup_test_img 34 rm -f "$TEST_IMG".v{2,3}.orig 35 rm -f "$TEST_DIR"/sn{0,1,2}{,-pre,-extra,-post} 36} 37trap "_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# $2: snapshot table entry offset in the image 56snapshot_table_entry_size() 57{ 58 id_len=$(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# $1: image filename 68print_snapshot_table() 69{ 70 nb_entries=$(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# $2: End offset (exclusive) 109refblock0_allocate() 110{ 111 reftable_ofs=$(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 128echo 129echo '=== Create v2 template ===' 130echo 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 138TEST_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 "$TEST_IMG.v2.orig" 142 143# Copy out all existing snapshot table entries 144sn_table_ofs=$(peek_file_be "$TEST_IMG.v2.orig" 64 8) 145 146# ofs: Snapshot table entry offset 147# eds: Extra data size 148# ids: Name + ID size 149# len: Total entry length 150sn0_ofs=$sn_table_ofs 151sn0_eds=$(peek_file_be "$TEST_IMG.v2.orig" $((sn0_ofs + 36)) 4) 152sn0_ids=$(($(peek_file_be "$TEST_IMG.v2.orig" $((sn0_ofs + 12)) 2) + 153 $(peek_file_be "$TEST_IMG.v2.orig" $((sn0_ofs + 14)) 2))) 154sn0_len=$(snapshot_table_entry_size "$TEST_IMG.v2.orig" $sn0_ofs) 155sn1_ofs=$((sn0_ofs + sn0_len)) 156sn1_eds=$(peek_file_be "$TEST_IMG.v2.orig" $((sn1_ofs + 36)) 4) 157sn1_ids=$(($(peek_file_be "$TEST_IMG.v2.orig" $((sn1_ofs + 12)) 2) + 158 $(peek_file_be "$TEST_IMG.v2.orig" $((sn1_ofs + 14)) 2))) 159sn1_len=$(snapshot_table_entry_size "$TEST_IMG.v2.orig" $sn1_ofs) 160sn2_ofs=$((sn1_ofs + sn1_len)) 161sn2_eds=$(peek_file_be "$TEST_IMG.v2.orig" $((sn2_ofs + 36)) 4) 162sn2_ids=$(($(peek_file_be "$TEST_IMG.v2.orig" $((sn2_ofs + 12)) 2) + 163 $(peek_file_be "$TEST_IMG.v2.orig" $((sn2_ofs + 14)) 2))) 164sn2_len=$(snapshot_table_entry_size "$TEST_IMG.v2.orig" $sn2_ofs) 165 166# Data before extra data 167dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn0-pre" bs=1 skip=$sn0_ofs count=40 \ 168 &> /dev/null 169dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn1-pre" bs=1 skip=$sn1_ofs count=40 \ 170 &> /dev/null 171dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn2-pre" bs=1 skip=$sn2_ofs count=40 \ 172 &> /dev/null 173 174# Extra data 175dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn0-extra" bs=1 \ 176 skip=$((sn0_ofs + 40)) count=$sn0_eds &> /dev/null 177dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn1-extra" bs=1 \ 178 skip=$((sn1_ofs + 40)) count=$sn1_eds &> /dev/null 179dd 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 183dd 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 186dd 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 189dd 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 195poke_file "$TEST_DIR/sn0-pre" 36 '\x00\x00\x00\x00' 196truncate -s 0 "$TEST_DIR/sn0-extra" 197# Grow sn0-post to pad 198truncate -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 202poke_file "$TEST_DIR/sn1-pre" 36 '\x00\x00\x00\x2a' 203truncate -s 42 "$TEST_DIR/sn1-extra" 204poke_file "$TEST_DIR/sn1-extra" 16 'very important data' 205# Grow sn1-post to pad 206truncate -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 210poke_file "$TEST_DIR/sn2-pre" 36 '\x00\x00\x00\x08' 211truncate -s 8 "$TEST_DIR/sn2-extra" 212# Grow sn2-post to pad 213truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn2-pre") - 48)) \ 214 "$TEST_DIR/sn2-post" 215 216# Construct snapshot table 217cat "$TEST_DIR"/sn0-{pre,extra,post} \ 218 "$TEST_DIR"/sn1-{pre,extra,post} \ 219 "$TEST_DIR"/sn2-{pre,extra,post} \ 220 | dd of="$TEST_IMG.v2.orig" bs=1 seek=$sn_table_ofs conv=notrunc \ 221 &> /dev/null 222 223# Done! 224TEST_IMG="$TEST_IMG.v2.orig" _check_test_img 225print_snapshot_table "$TEST_IMG.v2.orig" 226 227echo 228echo '=== Upgrade to v3 ===' 229echo 230 231cp "$TEST_IMG.v2.orig" "$TEST_IMG.v3.orig" 232$QEMU_IMG amend -o compat=1.1 "$TEST_IMG.v3.orig" 233TEST_IMG="$TEST_IMG.v3.orig" _check_test_img 234print_snapshot_table "$TEST_IMG.v3.orig" 235 236echo 237echo '=== Repair botched v3 ===' 238echo 239 240# Force the v2 file to be v3. v3 requires each snapshot table entry 241# to have at least 16 bytes of extra data, so it will not comply to 242# the qcow2 v3 specification; but we can fix that. 243cp "$TEST_IMG.v2.orig" "$TEST_IMG" 244 245# Set version 246poke_file "$TEST_IMG" 4 '\x00\x00\x00\x03' 247# Increase header length (necessary for v3) 248poke_file "$TEST_IMG" 100 '\x00\x00\x00\x68' 249# Set refcount order (necessary for v3) 250poke_file "$TEST_IMG" 96 '\x00\x00\x00\x04' 251 252_check_test_img -r all 253print_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 $IMGOPTS.) 258# That works because we always write all known extra data when 259# updating the snapshot table, independent of the version. 260 261if echo "$IMGOPTS" | grep -q 'compat=\(0\.10\|v2\)' 2> /dev/null; then 262 subver=v2 263else 264 subver=v3 265fi 266 267echo 268echo '=== Add new snapshot ===' 269echo 270 271cp "$TEST_IMG.$subver.orig" "$TEST_IMG" 272$QEMU_IMG snapshot -c sn3 "$TEST_IMG" 273_check_test_img 274print_snapshot_table "$TEST_IMG" 275 276echo 277echo '=== Remove different snapshots ===' 278 279for 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 "$TEST_IMG" 287done 288 289echo 290echo '=== Reject too much unknown extra data ===' 291echo 292 293cp "$TEST_IMG.$subver.orig" "$TEST_IMG" 294$QEMU_IMG snapshot -c sn3 "$TEST_IMG" 295 296sn_table_ofs=$(peek_file_be "$TEST_IMG" 64 8) 297sn0_ofs=$sn_table_ofs 298sn1_ofs=$((sn0_ofs + $(snapshot_table_entry_size "$TEST_IMG" $sn0_ofs))) 299sn2_ofs=$((sn1_ofs + $(snapshot_table_entry_size "$TEST_IMG" $sn1_ofs))) 300sn3_ofs=$((sn2_ofs + $(snapshot_table_entry_size "$TEST_IMG" $sn2_ofs))) 301 302# 64 kB of extra data should be rejected 303# (Note that this also induces a refcount error, because it spills 304# over to the next cluster. That's a good way to test that we can 305# handle simultaneous snapshot table and refcount errors.) 306poke_file "$TEST_IMG" $((sn3_ofs + 36)) '\x00\x01\x00\x00' 307 308# Print error 309_img_info 310echo 311_check_test_img 312echo 313 314# Should be repairable 315_check_test_img -r all 316 317echo 318echo '=== Snapshot table too big ===' 319echo 320 321sn_table_ofs=$(peek_file_be "$TEST_IMG.v3.orig" 64 8) 322 323# Fill a snapshot with 1 kB of extra data, a 65535-char ID, and a 324# 65535-char name, and repeat it as many times as necessary to fill 325# 64 MB (the maximum supported by qemu) 326 327touch "$TEST_DIR/sn0" 328 329# Full size (fixed + extra + ID + name + padding) 330sn_size=$((40 + 1024 + 65535 + 65535 + 2)) 331 332# We only need the fixed part, though. 333truncate -s 40 "$TEST_DIR/sn0" 334 335# 65535-char ID string 336poke_file "$TEST_DIR/sn0" 12 '\xff\xff' 337# 65535-char name 338poke_file "$TEST_DIR/sn0" 14 '\xff\xff' 339# 1 kB of extra data 340poke_file "$TEST_DIR/sn0" 36 '\x00\x00\x04\x00' 341 342# Create test image 343_make_test_img 64M 344 345# Hook up snapshot table somewhere safe (at 1 MB) 346poke_file "$TEST_IMG" 64 '\x00\x00\x00\x00\x00\x10\x00\x00' 347 348offset=1048576 349size_written=0 350sn_count=0 351while [ $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=$((sn_count + 1)) 357done 358truncate -s "$offset" "$TEST_IMG" 359 360# Give the last snapshot (the one to be removed) an L1 table so we can 361# see how that is handled when repairing the image 362# (Put it two clusters before 1 MB, and one L2 table one cluster 363# before 1 MB) 364poke_file "$TEST_IMG" $((offset - sn_size + 0)) \ 365 '\x00\x00\x00\x00\x00\x0e\x00\x00' 366poke_file "$TEST_IMG" $((offset - sn_size + 8)) \ 367 '\x00\x00\x00\x01' 368 369# Hook up the L2 table 370poke_file "$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 376refblock0_allocate $((1048576 - 2 * 65536)) $offset 377 378poke_file "$TEST_IMG" 60 \ 379 "$(printf '%08x' $sn_count | sed -e 's/\(..\)/\\x\1/g')" 380 381# Print error 382_img_info 383echo 384_check_test_img 385echo 386 387# Should be repairable 388_check_test_img -r all 389 390echo 391echo "$((sn_count - 1)) snapshots should remain:" 392echo " qemu-img info reports $(_img_info | grep -c '^ \{34\}') snapshots" 393echo " Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots" 394 395echo 396echo '=== Snapshot table too big with one entry with too much extra data ===' 397echo 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# $old_offset to get the current image's real length 416old_offset=$((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. 422offset=$((offset - 3 * sn_size)) 423sn_count=$((sn_count - 3)) 424 425# Assuming we had already written one of the three snapshots 426# (necessary so we can calculate $extra_data_size next). 427size_written=$((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) 431extra_data_size=$((64 * 1048576 + 8 - sn_size - (size_written - 1024))) 432 433poke_file "$TEST_IMG" $((offset + 36)) \ 434 "$(printf '%08x' $extra_data_size | sed -e 's/\(..\)/\\x\1/g')" 435 436offset=$((offset + sn_size - 1024 + extra_data_size)) 437size_written=$((size_written - 1024 + extra_data_size)) 438sn_count=$((sn_count + 1)) 439 440# Write the two normal snapshots 441for ((i = 0; i < 2; i++)); do 442 dd if="$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 454done 455 456truncate -s $offset "$TEST_IMG" 457refblock0_allocate $old_offset $offset 458 459poke_file "$TEST_IMG" 60 \ 460 "$(printf '%08x' $sn_count | sed -e 's/\(..\)/\\x\1/g')" 461 462# Print error 463_img_info 464echo 465_check_test_img 466echo 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 472echo 473echo '=== Too many snapshots ===' 474echo 475 476# Create a v2 image, for speeds' sake: All-zero snapshot table entries 477# are only valid in v2. 478IMGOPTS='compat=0.10' _make_test_img 64M 479 480# Hook up snapshot table somewhere safe (at 1 MB) 481poke_file "$TEST_IMG" 64 '\x00\x00\x00\x00\x00\x10\x00\x00' 482# "Create" more than 65536 snapshots (twice that many here) 483poke_file "$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'). 488truncate -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) 494poke_file "$TEST_IMG" $((1048576 + 40 * 65536 + 0)) \ 495 '\x00\x00\x00\x00\x00\x0e\x00\x00' 496poke_file "$TEST_IMG" $((1048576 + 40 * 65536 + 8)) \ 497 '\x00\x00\x00\x01' 498 499# Hook up the L2 table 500poke_file "$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 506refblock0_allocate $((1048576 - 2 * 65536)) $((1048576 + 40 * 131072)) 507 508# Print error 509_img_info 510echo 511_check_test_img 512echo 513 514# Should be repairable 515_check_test_img -r all 516 517echo 518echo '65536 snapshots should remain:' 519echo " qemu-img info reports $(_img_info | grep -c '^ \{34\}') snapshots" 520echo " Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots" 521 522# success, all done 523echo "*** done" 524status=0 525