4 # Test case for qcow2's handling of extra data in snapshot table entries
5 # (and more generally, how certain cases of broken snapshot tables are
8 # Copyright (C) 2019 Red Hat, Inc.
10 # This program is free software; you can redistribute it and/or modify
11 # it under the terms of the GNU General Public License as published by
12 # the Free Software Foundation; either version 2 of the License, or
13 # (at your option) any later version.
15 # This program is distributed in the hope that it will be useful,
16 # but WITHOUT ANY WARRANTY; without even the implied warranty of
17 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 # GNU General Public License for more details.
20 # You should have received a copy of the GNU General Public License
21 # along with this program. If not, see <http://www.gnu.org/licenses/>.
25 owner
=hreitz@redhat.com
28 echo "QA output created by $seq"
30 status
=1 # failure is the default!
35 rm -f "$TEST_IMG".v
{2,3}.orig
36 rm -f "$TEST_DIR"/sn
{0,1,2}{,-pre,-extra,-post}
38 trap "_cleanup; exit \$status" 0 1 2 3 15
40 # get standard environment, filters and checks
44 # This tests qcow2-specific low-level functionality
48 # (1) We create a v2 image that supports nothing but refcount_bits=16
49 # (2) We do some refcount management on our own which expects
51 # As for data files, they do not support snapshots at all.
52 _unsupported_imgopts
'refcount_bits=\([^1]\|.\([^6]\|$\)\)' data_file
56 # $2: snapshot table entry offset in the image
57 snapshot_table_entry_size
()
59 id_len
=$
(peek_file_be
"$1" $
(($2 + 12)) 2)
60 name_len
=$
(peek_file_be
"$1" $
(($2 + 14)) 2)
61 extra_len
=$
(peek_file_be
"$1" $
(($2 + 36)) 4)
63 full_len
=$
((40 + extra_len
+ id_len
+ name_len
))
64 echo $
(((full_len
+ 7) / 8 * 8))
69 print_snapshot_table
()
71 nb_entries
=$
(peek_file_be
"$1" 60 4)
72 offset
=$
(peek_file_be
"$1" 64 8)
74 echo "Snapshots in $1:" | _filter_testdir | _filter_imgfmt
76 for ((i
= 0; i
< nb_entries
; i
++)); do
77 id_len
=$
(peek_file_be
"$1" $
((offset
+ 12)) 2)
78 name_len
=$
(peek_file_be
"$1" $
((offset
+ 14)) 2)
79 extra_len
=$
(peek_file_be
"$1" $
((offset
+ 36)) 4)
81 extra_ofs
=$
((offset
+ 40))
82 id_ofs
=$
((extra_ofs
+ extra_len
))
83 name_ofs
=$
((id_ofs
+ id_len
))
86 echo " ID: $(peek_file_raw "$1" $id_ofs $id_len)"
87 echo " Name: $(peek_file_raw "$1" $name_ofs $name_len)"
88 echo " Extra data size: $extra_len"
89 if [ $extra_len -ge 8 ]; then
90 echo " VM state size: $(peek_file_be "$1" $extra_ofs 8)"
92 if [ $extra_len -ge 16 ]; then
93 echo " Disk size: $(peek_file_be "$1" $((extra_ofs + 8)) 8)"
95 if [ $extra_len -ge 24 ]; then
96 echo " Icount: $(peek_file_be "$1" $((extra_ofs + 16)) 8)"
98 if [ $extra_len -gt 24 ]; then
99 echo ' Unknown extra data:' \
100 "$(peek_file_raw "$1" $((extra_ofs + 16)) $((extra_len - 16)) \
104 offset
=$
((offset
+ $
(snapshot_table_entry_size
"$1" $offset)))
108 # Mark clusters as allocated; works only in refblock 0 (i.e. before
111 # $1: Start offset of what to allocate
112 # $2: End offset (exclusive)
115 reftable_ofs
=$
(peek_file_be
"$TEST_IMG" 48 8)
116 refblock_ofs
=$
(peek_file_be
"$TEST_IMG" $reftable_ofs 8)
118 cluster
=$
(($1 / 65536))
119 ecluster
=$
((($2 + 65535) / 65536))
121 while [ $cluster -lt $ecluster ]; do
122 if [ $cluster -ge 32768 ]; then
123 echo "*** Abort: Cluster $cluster exceeds refblock 0 ***"
126 poke_file
"$TEST_IMG" $
((refblock_ofs
+ cluster
* 2)) '\x00\x01'
127 cluster
=$
((cluster
+ 1))
133 echo '=== Create v2 template ==='
136 # Create v2 image with a snapshot table with three entries:
137 # [0]: No extra data (valid with v2, not valid with v3)
138 # [1]: Has extra data unknown to qemu
139 # [2]: Has the 64-bit VM state size, but not the disk size (again,
140 # valid with v2, not valid with v3)
142 TEST_IMG
="$TEST_IMG.v2.orig" IMGOPTS
='compat=0.10' _make_test_img
64M
143 $QEMU_IMG snapshot
-c sn0
"$TEST_IMG.v2.orig"
144 $QEMU_IMG snapshot
-c sn1
"$TEST_IMG.v2.orig"
145 $QEMU_IMG snapshot
-c sn2
"$TEST_IMG.v2.orig"
147 # Copy out all existing snapshot table entries
148 sn_table_ofs
=$
(peek_file_be
"$TEST_IMG.v2.orig" 64 8)
150 # ofs: Snapshot table entry offset
151 # eds: Extra data size
152 # ids: Name + ID size
153 # len: Total entry length
154 sn0_ofs
=$sn_table_ofs
155 sn0_eds
=$
(peek_file_be
"$TEST_IMG.v2.orig" $
((sn0_ofs
+ 36)) 4)
156 sn0_ids
=$
(($
(peek_file_be
"$TEST_IMG.v2.orig" $
((sn0_ofs
+ 12)) 2) +
157 $
(peek_file_be
"$TEST_IMG.v2.orig" $
((sn0_ofs
+ 14)) 2)))
158 sn0_len
=$
(snapshot_table_entry_size
"$TEST_IMG.v2.orig" $sn0_ofs)
159 sn1_ofs
=$
((sn0_ofs
+ sn0_len
))
160 sn1_eds
=$
(peek_file_be
"$TEST_IMG.v2.orig" $
((sn1_ofs
+ 36)) 4)
161 sn1_ids
=$
(($
(peek_file_be
"$TEST_IMG.v2.orig" $
((sn1_ofs
+ 12)) 2) +
162 $
(peek_file_be
"$TEST_IMG.v2.orig" $
((sn1_ofs
+ 14)) 2)))
163 sn1_len
=$
(snapshot_table_entry_size
"$TEST_IMG.v2.orig" $sn1_ofs)
164 sn2_ofs
=$
((sn1_ofs
+ sn1_len
))
165 sn2_eds
=$
(peek_file_be
"$TEST_IMG.v2.orig" $
((sn2_ofs
+ 36)) 4)
166 sn2_ids
=$
(($
(peek_file_be
"$TEST_IMG.v2.orig" $
((sn2_ofs
+ 12)) 2) +
167 $
(peek_file_be
"$TEST_IMG.v2.orig" $
((sn2_ofs
+ 14)) 2)))
168 sn2_len
=$
(snapshot_table_entry_size
"$TEST_IMG.v2.orig" $sn2_ofs)
170 # Data before extra data
171 dd if="$TEST_IMG.v2.orig" of
="$TEST_DIR/sn0-pre" bs
=1 skip
=$sn0_ofs count
=40 \
173 dd if="$TEST_IMG.v2.orig" of
="$TEST_DIR/sn1-pre" bs
=1 skip
=$sn1_ofs count
=40 \
175 dd if="$TEST_IMG.v2.orig" of
="$TEST_DIR/sn2-pre" bs
=1 skip
=$sn2_ofs count
=40 \
179 dd if="$TEST_IMG.v2.orig" of
="$TEST_DIR/sn0-extra" bs
=1 \
180 skip
=$
((sn0_ofs
+ 40)) count
=$sn0_eds &> /dev
/null
181 dd if="$TEST_IMG.v2.orig" of
="$TEST_DIR/sn1-extra" bs
=1 \
182 skip
=$
((sn1_ofs
+ 40)) count
=$sn1_eds &> /dev
/null
183 dd if="$TEST_IMG.v2.orig" of
="$TEST_DIR/sn2-extra" bs
=1 \
184 skip
=$
((sn2_ofs
+ 40)) count
=$sn2_eds &> /dev
/null
186 # Data after extra data
187 dd if="$TEST_IMG.v2.orig" of
="$TEST_DIR/sn0-post" bs
=1 \
188 skip
=$
((sn0_ofs
+ 40 + sn0_eds
)) count
=$sn0_ids \
190 dd if="$TEST_IMG.v2.orig" of
="$TEST_DIR/sn1-post" bs
=1 \
191 skip
=$
((sn1_ofs
+ 40 + sn1_eds
)) count
=$sn1_ids \
193 dd if="$TEST_IMG.v2.orig" of
="$TEST_DIR/sn2-post" bs
=1 \
194 skip
=$
((sn2_ofs
+ 40 + sn2_eds
)) count
=$sn2_ids \
197 # Amend them, one by one
198 # Set sn0's extra data size to 0
199 poke_file
"$TEST_DIR/sn0-pre" 36 '\x00\x00\x00\x00'
200 truncate
-s 0 "$TEST_DIR/sn0-extra"
201 # Grow sn0-post to pad
202 truncate
-s $
(($
(snapshot_table_entry_size
"$TEST_DIR/sn0-pre") - 40)) \
205 # Set sn1's extra data size to 50
206 poke_file
"$TEST_DIR/sn1-pre" 36 '\x00\x00\x00\x32'
207 truncate
-s 50 "$TEST_DIR/sn1-extra"
208 poke_file
"$TEST_DIR/sn1-extra" 24 'very important data'
209 # Grow sn1-post to pad
210 truncate
-s $
(($
(snapshot_table_entry_size
"$TEST_DIR/sn1-pre") - 90)) \
213 # Set sn2's extra data size to 8
214 poke_file
"$TEST_DIR/sn2-pre" 36 '\x00\x00\x00\x08'
215 truncate
-s 8 "$TEST_DIR/sn2-extra"
216 # Grow sn2-post to pad
217 truncate
-s $
(($
(snapshot_table_entry_size
"$TEST_DIR/sn2-pre") - 48)) \
220 # Construct snapshot table
221 cat "$TEST_DIR"/sn0-
{pre
,extra
,post
} \
222 "$TEST_DIR"/sn1-
{pre
,extra
,post
} \
223 "$TEST_DIR"/sn2-
{pre
,extra
,post
} \
224 |
dd of
="$TEST_IMG.v2.orig" bs
=1 seek
=$sn_table_ofs conv
=notrunc \
228 TEST_IMG
="$TEST_IMG.v2.orig" _check_test_img
229 print_snapshot_table
"$TEST_IMG.v2.orig"
232 echo '=== Upgrade to v3 ==='
235 cp "$TEST_IMG.v2.orig" "$TEST_IMG.v3.orig"
236 $QEMU_IMG amend
-o compat
=1.1 "$TEST_IMG.v3.orig"
237 TEST_IMG
="$TEST_IMG.v3.orig" _check_test_img
238 print_snapshot_table
"$TEST_IMG.v3.orig"
241 echo '=== Repair botched v3 ==='
244 # Force the v2 file to be v3. v3 requires each snapshot table entry
245 # to have at least 16 bytes of extra data, so it will not comply to
246 # the qcow2 v3 specification; but we can fix that.
247 cp "$TEST_IMG.v2.orig" "$TEST_IMG"
250 poke_file
"$TEST_IMG" 4 '\x00\x00\x00\x03'
251 # Increase header length (necessary for v3)
252 poke_file
"$TEST_IMG" 100 '\x00\x00\x00\x68'
253 # Set refcount order (necessary for v3)
254 poke_file
"$TEST_IMG" 96 '\x00\x00\x00\x04'
256 _check_test_img
-r all
257 print_snapshot_table
"$TEST_IMG"
260 # From now on, just test the qcow2 version we are supposed to test.
261 # (v3 by default, v2 by choice through $IMGOPTS.)
262 # That works because we always write all known extra data when
263 # updating the snapshot table, independent of the version.
265 if echo "$IMGOPTS" |
grep -q 'compat=\(0\.10\|v2\)' 2> /dev
/null
; then
272 echo '=== Add new snapshot ==='
275 cp "$TEST_IMG.$subver.orig" "$TEST_IMG"
276 $QEMU_IMG snapshot
-c sn3
"$TEST_IMG"
278 print_snapshot_table
"$TEST_IMG"
281 echo '=== Remove different snapshots ==='
283 for sn
in sn0 sn1 sn2
; do
287 cp "$TEST_IMG.$subver.orig" "$TEST_IMG"
288 $QEMU_IMG snapshot
-d $sn "$TEST_IMG"
290 print_snapshot_table
"$TEST_IMG"
294 echo '=== Reject too much unknown extra data ==='
297 cp "$TEST_IMG.$subver.orig" "$TEST_IMG"
298 $QEMU_IMG snapshot
-c sn3
"$TEST_IMG"
300 sn_table_ofs
=$
(peek_file_be
"$TEST_IMG" 64 8)
301 sn0_ofs
=$sn_table_ofs
302 sn1_ofs
=$
((sn0_ofs
+ $
(snapshot_table_entry_size
"$TEST_IMG" $sn0_ofs)))
303 sn2_ofs
=$
((sn1_ofs
+ $
(snapshot_table_entry_size
"$TEST_IMG" $sn1_ofs)))
304 sn3_ofs
=$
((sn2_ofs
+ $
(snapshot_table_entry_size
"$TEST_IMG" $sn2_ofs)))
306 # 64 kB of extra data should be rejected
307 # (Note that this also induces a refcount error, because it spills
308 # over to the next cluster. That's a good way to test that we can
309 # handle simultaneous snapshot table and refcount errors.)
310 poke_file
"$TEST_IMG" $
((sn3_ofs
+ 36)) '\x00\x01\x00\x00'
318 # Should be repairable
319 _check_test_img
-r all
322 echo '=== Snapshot table too big ==='
325 sn_table_ofs
=$
(peek_file_be
"$TEST_IMG.v3.orig" 64 8)
327 # Fill a snapshot with 1 kB of extra data, a 65535-char ID, and a
328 # 65535-char name, and repeat it as many times as necessary to fill
329 # 64 MB (the maximum supported by qemu)
331 touch "$TEST_DIR/sn0"
333 # Full size (fixed + extra + ID + name + padding)
334 sn_size
=$
((40 + 1024 + 65535 + 65535 + 2))
336 # We only need the fixed part, though.
337 truncate
-s 40 "$TEST_DIR/sn0"
339 # 65535-char ID string
340 poke_file
"$TEST_DIR/sn0" 12 '\xff\xff'
342 poke_file
"$TEST_DIR/sn0" 14 '\xff\xff'
344 poke_file
"$TEST_DIR/sn0" 36 '\x00\x00\x04\x00'
349 # Hook up snapshot table somewhere safe (at 1 MB)
350 poke_file
"$TEST_IMG" 64 '\x00\x00\x00\x00\x00\x10\x00\x00'
355 while [ $size_written -le $
((64 * 1048576)) ]; do
356 dd if="$TEST_DIR/sn0" of
="$TEST_IMG" bs
=1 seek
=$offset conv
=notrunc \
358 offset
=$
((offset
+ sn_size
))
359 size_written
=$
((size_written
+ sn_size
))
360 sn_count
=$
((sn_count
+ 1))
362 truncate
-s "$offset" "$TEST_IMG"
364 # Give the last snapshot (the one to be removed) an L1 table so we can
365 # see how that is handled when repairing the image
366 # (Put it two clusters before 1 MB, and one L2 table one cluster
368 poke_file
"$TEST_IMG" $
((offset
- sn_size
+ 0)) \
369 '\x00\x00\x00\x00\x00\x0e\x00\x00'
370 poke_file
"$TEST_IMG" $
((offset
- sn_size
+ 8)) \
373 # Hook up the L2 table
374 poke_file
"$TEST_IMG" $
((1048576 - 2 * 65536)) \
375 '\x80\x00\x00\x00\x00\x0f\x00\x00'
377 # Make sure all of the clusters we just hooked up are allocated:
378 # - The snapshot table
379 # - The last snapshot's L1 and L2 table
380 refblock0_allocate $
((1048576 - 2 * 65536)) $offset
382 poke_file
"$TEST_IMG" 60 \
383 "$(printf '%08x' $sn_count | sed -e 's/\(..\)/\\x\1/g')"
391 # Should be repairable
392 _check_test_img
-r all
395 echo "$((sn_count - 1)) snapshots should remain:"
396 echo " qemu-img info reports $(_img_info | grep -c '^ \{32\}') snapshots"
397 echo " Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots"
400 echo '=== Snapshot table too big with one entry with too much extra data ==='
403 # For this test, we reuse the image from the previous case, which has
404 # a snapshot table that is right at the limit.
405 # Our layout looks like this:
406 # - (a number of snapshot table entries)
407 # - One snapshot with $extra_data_size extra data
408 # - One normal snapshot that breaks the 64 MB boundary
409 # - One normal snapshot beyond the 64 MB boundary
411 # $extra_data_size is calculated so that simply by virtue of it
412 # decreasing to 1 kB, the penultimate snapshot will fit into 64 MB
413 # limit again. The final snapshot will always be beyond the limit, so
414 # that we can see that the repair algorithm does still determine the
415 # limit to be somewhere, even when truncating one snapshot's extra
418 # The last case has removed the last snapshot, so calculate
419 # $old_offset to get the current image's real length
420 old_offset
=$
((offset
- sn_size
))
422 # The layout from the previous test had one snapshot beyond the 64 MB
423 # limit; we want the same (after the oversized extra data has been
424 # truncated to 1 kB), so we drop the last three snapshots and
425 # construct them from scratch.
426 offset
=$
((offset
- 3 * sn_size
))
427 sn_count
=$
((sn_count
- 3))
429 # Assuming we had already written one of the three snapshots
430 # (necessary so we can calculate $extra_data_size next).
431 size_written
=$
((size_written
- 2 * sn_size
))
433 # Increase the extra data size so we go past the limit
434 # (The -1024 comes from the 1 kB of extra data we already have)
435 extra_data_size
=$
((64 * 1048576 + 8 - sn_size
- (size_written
- 1024)))
437 poke_file
"$TEST_IMG" $
((offset
+ 36)) \
438 "$(printf '%08x' $extra_data_size | sed -e 's/\(..\)/\\x\1/g')"
440 offset
=$
((offset
+ sn_size
- 1024 + extra_data_size
))
441 size_written
=$
((size_written
- 1024 + extra_data_size
))
442 sn_count
=$
((sn_count
+ 1))
444 # Write the two normal snapshots
445 for ((i
= 0; i
< 2; i
++)); do
446 dd if="$TEST_DIR/sn0" of
="$TEST_IMG" bs
=1 seek
=$offset conv
=notrunc \
448 offset
=$
((offset
+ sn_size
))
449 size_written
=$
((size_written
+ sn_size
))
450 sn_count
=$
((sn_count
+ 1))
453 # Check that the penultimate snapshot is beyond the 64 MB limit
454 echo "Snapshot table size should equal $((64 * 1048576 + 8)):" \
460 truncate
-s $offset "$TEST_IMG"
461 refblock0_allocate
$old_offset $offset
463 poke_file
"$TEST_IMG" 60 \
464 "$(printf '%08x' $sn_count | sed -e 's/\(..\)/\\x\1/g')"
472 # Just truncating the extra data should be sufficient to shorten the
473 # snapshot table so only one snapshot exceeds the extra size
474 _check_test_img
-r all
477 echo '=== Too many snapshots ==='
480 # Create a v2 image, for speeds' sake: All-zero snapshot table entries
481 # are only valid in v2.
482 IMGOPTS
='compat=0.10' _make_test_img
64M
484 # Hook up snapshot table somewhere safe (at 1 MB)
485 poke_file
"$TEST_IMG" 64 '\x00\x00\x00\x00\x00\x10\x00\x00'
486 # "Create" more than 65536 snapshots (twice that many here)
487 poke_file
"$TEST_IMG" 60 '\x00\x02\x00\x00'
489 # 40-byte all-zero snapshot table entries are valid snapshots, but
490 # only in v2 (v3 needs 16 bytes of extra data, so we would have to
491 # write 131072x '\x10').
492 truncate
-s $
((1048576 + 40 * 131072)) "$TEST_IMG"
494 # But let us give one of the snapshots to be removed an L1 table so
495 # we can see how that is handled when repairing the image.
496 # (Put it two clusters before 1 MB, and one L2 table one cluster
498 poke_file
"$TEST_IMG" $
((1048576 + 40 * 65536 + 0)) \
499 '\x00\x00\x00\x00\x00\x0e\x00\x00'
500 poke_file
"$TEST_IMG" $
((1048576 + 40 * 65536 + 8)) \
503 # Hook up the L2 table
504 poke_file
"$TEST_IMG" $
((1048576 - 2 * 65536)) \
505 '\x80\x00\x00\x00\x00\x0f\x00\x00'
507 # Make sure all of the clusters we just hooked up are allocated:
508 # - The snapshot table
509 # - The last snapshot's L1 and L2 table
510 refblock0_allocate $
((1048576 - 2 * 65536)) $
((1048576 + 40 * 131072))
518 # Should be repairable
519 _check_test_img
-r all
522 echo '65536 snapshots should remain:'
523 echo " qemu-img info reports $(_img_info | grep -c '^ \{32\}') snapshots"
524 echo " Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots"