#!/usr/bin/env bash # group: rw # # Test case for qcow2's handling of extra data in snapshot table entries # (and more generally, how certain cases of broken snapshot tables are # handled) # # Copyright (C) 2019 Red Hat, Inc. # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see <http://www.gnu.org/licenses/>. # # creator owner=mreitz@redhat.com seq=$(basename $0) echo "QA output created by $seq" status=1 # failure is the default! _cleanup() { _cleanup_test_img rm -f "$TEST_IMG".v{2,3}.orig rm -f "$TEST_DIR"/sn{0,1,2}{,-pre,-extra,-post} } trap "_cleanup; exit \$status" 0 1 2 3 15 # get standard environment, filters and checks . ./common.rc . ./common.filter # This tests qcow2-specific low-level functionality _supported_fmt qcow2 _supported_proto file _supported_os Linux # (1) We create a v2 image that supports nothing but refcount_bits=16 # (2) We do some refcount management on our own which expects # refcount_bits=16 # As for data files, they do not support snapshots at all. _unsupported_imgopts 'refcount_bits=\([^1]\|.\([^6]\|$\)\)' data_file # Parameters: # $1: image filename # $2: snapshot table entry offset in the image snapshot_table_entry_size() { id_len=$(peek_file_be "$1" $(($2 + 12)) 2) name_len=$(peek_file_be "$1" $(($2 + 14)) 2) extra_len=$(peek_file_be "$1" $(($2 + 36)) 4) full_len=$((40 + extra_len + id_len + name_len)) echo $(((full_len + 7) / 8 * 8)) } # Parameter: # $1: image filename print_snapshot_table() { nb_entries=$(peek_file_be "$1" 60 4) offset=$(peek_file_be "$1" 64 8) echo "Snapshots in $1:" | _filter_testdir | _filter_imgfmt for ((i = 0; i < nb_entries; i++)); do id_len=$(peek_file_be "$1" $((offset + 12)) 2) name_len=$(peek_file_be "$1" $((offset + 14)) 2) extra_len=$(peek_file_be "$1" $((offset + 36)) 4) extra_ofs=$((offset + 40)) id_ofs=$((extra_ofs + extra_len)) name_ofs=$((id_ofs + id_len)) echo " [$i]" echo " ID: $(peek_file_raw "$1" $id_ofs $id_len)" echo " Name: $(peek_file_raw "$1" $name_ofs $name_len)" echo " Extra data size: $extra_len" if [ $extra_len -ge 8 ]; then echo " VM state size: $(peek_file_be "$1" $extra_ofs 8)" fi if [ $extra_len -ge 16 ]; then echo " Disk size: $(peek_file_be "$1" $((extra_ofs + 8)) 8)" fi if [ $extra_len -ge 24 ]; then echo " Icount: $(peek_file_be "$1" $((extra_ofs + 16)) 8)" fi if [ $extra_len -gt 24 ]; then echo ' Unknown extra data:' \ "$(peek_file_raw "$1" $((extra_ofs + 16)) $((extra_len - 16)) \ | tr -d '\0')" fi offset=$((offset + $(snapshot_table_entry_size "$1" $offset))) done } # Mark clusters as allocated; works only in refblock 0 (i.e. before # cluster #32768). # Parameters: # $1: Start offset of what to allocate # $2: End offset (exclusive) refblock0_allocate() { reftable_ofs=$(peek_file_be "$TEST_IMG" 48 8) refblock_ofs=$(peek_file_be "$TEST_IMG" $reftable_ofs 8) cluster=$(($1 / 65536)) ecluster=$((($2 + 65535) / 65536)) while [ $cluster -lt $ecluster ]; do if [ $cluster -ge 32768 ]; then echo "*** Abort: Cluster $cluster exceeds refblock 0 ***" exit 1 fi poke_file "$TEST_IMG" $((refblock_ofs + cluster * 2)) '\x00\x01' cluster=$((cluster + 1)) done } echo echo '=== Create v2 template ===' echo # Create v2 image with a snapshot table with three entries: # [0]: No extra data (valid with v2, not valid with v3) # [1]: Has extra data unknown to qemu # [2]: Has the 64-bit VM state size, but not the disk size (again, # valid with v2, not valid with v3) TEST_IMG="$TEST_IMG.v2.orig" IMGOPTS='compat=0.10' _make_test_img 64M $QEMU_IMG snapshot -c sn0 "$TEST_IMG.v2.orig" $QEMU_IMG snapshot -c sn1 "$TEST_IMG.v2.orig" $QEMU_IMG snapshot -c sn2 "$TEST_IMG.v2.orig" # Copy out all existing snapshot table entries sn_table_ofs=$(peek_file_be "$TEST_IMG.v2.orig" 64 8) # ofs: Snapshot table entry offset # eds: Extra data size # ids: Name + ID size # len: Total entry length sn0_ofs=$sn_table_ofs sn0_eds=$(peek_file_be "$TEST_IMG.v2.orig" $((sn0_ofs + 36)) 4) sn0_ids=$(($(peek_file_be "$TEST_IMG.v2.orig" $((sn0_ofs + 12)) 2) + $(peek_file_be "$TEST_IMG.v2.orig" $((sn0_ofs + 14)) 2))) sn0_len=$(snapshot_table_entry_size "$TEST_IMG.v2.orig" $sn0_ofs) sn1_ofs=$((sn0_ofs + sn0_len)) sn1_eds=$(peek_file_be "$TEST_IMG.v2.orig" $((sn1_ofs + 36)) 4) sn1_ids=$(($(peek_file_be "$TEST_IMG.v2.orig" $((sn1_ofs + 12)) 2) + $(peek_file_be "$TEST_IMG.v2.orig" $((sn1_ofs + 14)) 2))) sn1_len=$(snapshot_table_entry_size "$TEST_IMG.v2.orig" $sn1_ofs) sn2_ofs=$((sn1_ofs + sn1_len)) sn2_eds=$(peek_file_be "$TEST_IMG.v2.orig" $((sn2_ofs + 36)) 4) sn2_ids=$(($(peek_file_be "$TEST_IMG.v2.orig" $((sn2_ofs + 12)) 2) + $(peek_file_be "$TEST_IMG.v2.orig" $((sn2_ofs + 14)) 2))) sn2_len=$(snapshot_table_entry_size "$TEST_IMG.v2.orig" $sn2_ofs) # Data before extra data dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn0-pre" bs=1 skip=$sn0_ofs count=40 \ &> /dev/null dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn1-pre" bs=1 skip=$sn1_ofs count=40 \ &> /dev/null dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn2-pre" bs=1 skip=$sn2_ofs count=40 \ &> /dev/null # Extra data dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn0-extra" bs=1 \ skip=$((sn0_ofs + 40)) count=$sn0_eds &> /dev/null dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn1-extra" bs=1 \ skip=$((sn1_ofs + 40)) count=$sn1_eds &> /dev/null dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn2-extra" bs=1 \ skip=$((sn2_ofs + 40)) count=$sn2_eds &> /dev/null # Data after extra data dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn0-post" bs=1 \ skip=$((sn0_ofs + 40 + sn0_eds)) count=$sn0_ids \ &> /dev/null dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn1-post" bs=1 \ skip=$((sn1_ofs + 40 + sn1_eds)) count=$sn1_ids \ &> /dev/null dd if="$TEST_IMG.v2.orig" of="$TEST_DIR/sn2-post" bs=1 \ skip=$((sn2_ofs + 40 + sn2_eds)) count=$sn2_ids \ &> /dev/null # Amend them, one by one # Set sn0's extra data size to 0 poke_file "$TEST_DIR/sn0-pre" 36 '\x00\x00\x00\x00' truncate -s 0 "$TEST_DIR/sn0-extra" # Grow sn0-post to pad truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn0-pre") - 40)) \ "$TEST_DIR/sn0-post" # Set sn1's extra data size to 50 poke_file "$TEST_DIR/sn1-pre" 36 '\x00\x00\x00\x32' truncate -s 50 "$TEST_DIR/sn1-extra" poke_file "$TEST_DIR/sn1-extra" 24 'very important data' # Grow sn1-post to pad truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn1-pre") - 90)) \ "$TEST_DIR/sn1-post" # Set sn2's extra data size to 8 poke_file "$TEST_DIR/sn2-pre" 36 '\x00\x00\x00\x08' truncate -s 8 "$TEST_DIR/sn2-extra" # Grow sn2-post to pad truncate -s $(($(snapshot_table_entry_size "$TEST_DIR/sn2-pre") - 48)) \ "$TEST_DIR/sn2-post" # Construct snapshot table cat "$TEST_DIR"/sn0-{pre,extra,post} \ "$TEST_DIR"/sn1-{pre,extra,post} \ "$TEST_DIR"/sn2-{pre,extra,post} \ | dd of="$TEST_IMG.v2.orig" bs=1 seek=$sn_table_ofs conv=notrunc \ &> /dev/null # Done! TEST_IMG="$TEST_IMG.v2.orig" _check_test_img print_snapshot_table "$TEST_IMG.v2.orig" echo echo '=== Upgrade to v3 ===' echo cp "$TEST_IMG.v2.orig" "$TEST_IMG.v3.orig" $QEMU_IMG amend -o compat=1.1 "$TEST_IMG.v3.orig" TEST_IMG="$TEST_IMG.v3.orig" _check_test_img print_snapshot_table "$TEST_IMG.v3.orig" echo echo '=== Repair botched v3 ===' echo # Force the v2 file to be v3. v3 requires each snapshot table entry # to have at least 16 bytes of extra data, so it will not comply to # the qcow2 v3 specification; but we can fix that. cp "$TEST_IMG.v2.orig" "$TEST_IMG" # Set version poke_file "$TEST_IMG" 4 '\x00\x00\x00\x03' # Increase header length (necessary for v3) poke_file "$TEST_IMG" 100 '\x00\x00\x00\x68' # Set refcount order (necessary for v3) poke_file "$TEST_IMG" 96 '\x00\x00\x00\x04' _check_test_img -r all print_snapshot_table "$TEST_IMG" # From now on, just test the qcow2 version we are supposed to test. # (v3 by default, v2 by choice through $IMGOPTS.) # That works because we always write all known extra data when # updating the snapshot table, independent of the version. if echo "$IMGOPTS" | grep -q 'compat=\(0\.10\|v2\)' 2> /dev/null; then subver=v2 else subver=v3 fi echo echo '=== Add new snapshot ===' echo cp "$TEST_IMG.$subver.orig" "$TEST_IMG" $QEMU_IMG snapshot -c sn3 "$TEST_IMG" _check_test_img print_snapshot_table "$TEST_IMG" echo echo '=== Remove different snapshots ===' for sn in sn0 sn1 sn2; do echo echo "--- $sn ---" cp "$TEST_IMG.$subver.orig" "$TEST_IMG" $QEMU_IMG snapshot -d $sn "$TEST_IMG" _check_test_img print_snapshot_table "$TEST_IMG" done echo echo '=== Reject too much unknown extra data ===' echo cp "$TEST_IMG.$subver.orig" "$TEST_IMG" $QEMU_IMG snapshot -c sn3 "$TEST_IMG" sn_table_ofs=$(peek_file_be "$TEST_IMG" 64 8) sn0_ofs=$sn_table_ofs sn1_ofs=$((sn0_ofs + $(snapshot_table_entry_size "$TEST_IMG" $sn0_ofs))) sn2_ofs=$((sn1_ofs + $(snapshot_table_entry_size "$TEST_IMG" $sn1_ofs))) sn3_ofs=$((sn2_ofs + $(snapshot_table_entry_size "$TEST_IMG" $sn2_ofs))) # 64 kB of extra data should be rejected # (Note that this also induces a refcount error, because it spills # over to the next cluster. That's a good way to test that we can # handle simultaneous snapshot table and refcount errors.) poke_file "$TEST_IMG" $((sn3_ofs + 36)) '\x00\x01\x00\x00' # Print error _img_info echo _check_test_img echo # Should be repairable _check_test_img -r all echo echo '=== Snapshot table too big ===' echo sn_table_ofs=$(peek_file_be "$TEST_IMG.v3.orig" 64 8) # Fill a snapshot with 1 kB of extra data, a 65535-char ID, and a # 65535-char name, and repeat it as many times as necessary to fill # 64 MB (the maximum supported by qemu) touch "$TEST_DIR/sn0" # Full size (fixed + extra + ID + name + padding) sn_size=$((40 + 1024 + 65535 + 65535 + 2)) # We only need the fixed part, though. truncate -s 40 "$TEST_DIR/sn0" # 65535-char ID string poke_file "$TEST_DIR/sn0" 12 '\xff\xff' # 65535-char name poke_file "$TEST_DIR/sn0" 14 '\xff\xff' # 1 kB of extra data poke_file "$TEST_DIR/sn0" 36 '\x00\x00\x04\x00' # Create test image _make_test_img 64M # Hook up snapshot table somewhere safe (at 1 MB) poke_file "$TEST_IMG" 64 '\x00\x00\x00\x00\x00\x10\x00\x00' offset=1048576 size_written=0 sn_count=0 while [ $size_written -le $((64 * 1048576)) ]; do dd if="$TEST_DIR/sn0" of="$TEST_IMG" bs=1 seek=$offset conv=notrunc \ &> /dev/null offset=$((offset + sn_size)) size_written=$((size_written + sn_size)) sn_count=$((sn_count + 1)) done truncate -s "$offset" "$TEST_IMG" # Give the last snapshot (the one to be removed) an L1 table so we can # see how that is handled when repairing the image # (Put it two clusters before 1 MB, and one L2 table one cluster # before 1 MB) poke_file "$TEST_IMG" $((offset - sn_size + 0)) \ '\x00\x00\x00\x00\x00\x0e\x00\x00' poke_file "$TEST_IMG" $((offset - sn_size + 8)) \ '\x00\x00\x00\x01' # Hook up the L2 table poke_file "$TEST_IMG" $((1048576 - 2 * 65536)) \ '\x80\x00\x00\x00\x00\x0f\x00\x00' # Make sure all of the clusters we just hooked up are allocated: # - The snapshot table # - The last snapshot's L1 and L2 table refblock0_allocate $((1048576 - 2 * 65536)) $offset poke_file "$TEST_IMG" 60 \ "$(printf '%08x' $sn_count | sed -e 's/\(..\)/\\x\1/g')" # Print error _img_info echo _check_test_img echo # Should be repairable _check_test_img -r all echo echo "$((sn_count - 1)) snapshots should remain:" echo " qemu-img info reports $(_img_info | grep -c '^ \{32\}') snapshots" echo " Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots" echo echo '=== Snapshot table too big with one entry with too much extra data ===' echo # For this test, we reuse the image from the previous case, which has # a snapshot table that is right at the limit. # Our layout looks like this: # - (a number of snapshot table entries) # - One snapshot with $extra_data_size extra data # - One normal snapshot that breaks the 64 MB boundary # - One normal snapshot beyond the 64 MB boundary # # $extra_data_size is calculated so that simply by virtue of it # decreasing to 1 kB, the penultimate snapshot will fit into 64 MB # limit again. The final snapshot will always be beyond the limit, so # that we can see that the repair algorithm does still determine the # limit to be somewhere, even when truncating one snapshot's extra # data. # The last case has removed the last snapshot, so calculate # $old_offset to get the current image's real length old_offset=$((offset - sn_size)) # The layout from the previous test had one snapshot beyond the 64 MB # limit; we want the same (after the oversized extra data has been # truncated to 1 kB), so we drop the last three snapshots and # construct them from scratch. offset=$((offset - 3 * sn_size)) sn_count=$((sn_count - 3)) # Assuming we had already written one of the three snapshots # (necessary so we can calculate $extra_data_size next). size_written=$((size_written - 2 * sn_size)) # Increase the extra data size so we go past the limit # (The -1024 comes from the 1 kB of extra data we already have) extra_data_size=$((64 * 1048576 + 8 - sn_size - (size_written - 1024))) poke_file "$TEST_IMG" $((offset + 36)) \ "$(printf '%08x' $extra_data_size | sed -e 's/\(..\)/\\x\1/g')" offset=$((offset + sn_size - 1024 + extra_data_size)) size_written=$((size_written - 1024 + extra_data_size)) sn_count=$((sn_count + 1)) # Write the two normal snapshots for ((i = 0; i < 2; i++)); do dd if="$TEST_DIR/sn0" of="$TEST_IMG" bs=1 seek=$offset conv=notrunc \ &> /dev/null offset=$((offset + sn_size)) size_written=$((size_written + sn_size)) sn_count=$((sn_count + 1)) if [ $i = 0 ]; then # Check that the penultimate snapshot is beyond the 64 MB limit echo "Snapshot table size should equal $((64 * 1048576 + 8)):" \ $size_written echo fi done truncate -s $offset "$TEST_IMG" refblock0_allocate $old_offset $offset poke_file "$TEST_IMG" 60 \ "$(printf '%08x' $sn_count | sed -e 's/\(..\)/\\x\1/g')" # Print error _img_info echo _check_test_img echo # Just truncating the extra data should be sufficient to shorten the # snapshot table so only one snapshot exceeds the extra size _check_test_img -r all echo echo '=== Too many snapshots ===' echo # Create a v2 image, for speeds' sake: All-zero snapshot table entries # are only valid in v2. IMGOPTS='compat=0.10' _make_test_img 64M # Hook up snapshot table somewhere safe (at 1 MB) poke_file "$TEST_IMG" 64 '\x00\x00\x00\x00\x00\x10\x00\x00' # "Create" more than 65536 snapshots (twice that many here) poke_file "$TEST_IMG" 60 '\x00\x02\x00\x00' # 40-byte all-zero snapshot table entries are valid snapshots, but # only in v2 (v3 needs 16 bytes of extra data, so we would have to # write 131072x '\x10'). truncate -s $((1048576 + 40 * 131072)) "$TEST_IMG" # But let us give one of the snapshots to be removed an L1 table so # we can see how that is handled when repairing the image. # (Put it two clusters before 1 MB, and one L2 table one cluster # before 1 MB) poke_file "$TEST_IMG" $((1048576 + 40 * 65536 + 0)) \ '\x00\x00\x00\x00\x00\x0e\x00\x00' poke_file "$TEST_IMG" $((1048576 + 40 * 65536 + 8)) \ '\x00\x00\x00\x01' # Hook up the L2 table poke_file "$TEST_IMG" $((1048576 - 2 * 65536)) \ '\x80\x00\x00\x00\x00\x0f\x00\x00' # Make sure all of the clusters we just hooked up are allocated: # - The snapshot table # - The last snapshot's L1 and L2 table refblock0_allocate $((1048576 - 2 * 65536)) $((1048576 + 40 * 131072)) # Print error _img_info echo _check_test_img echo # Should be repairable _check_test_img -r all echo echo '65536 snapshots should remain:' echo " qemu-img info reports $(_img_info | grep -c '^ \{32\}') snapshots" echo " Image header reports $(peek_file_be "$TEST_IMG" 60 4) snapshots" # success, all done echo "*** done" status=0