diff options
| -rw-r--r-- | block/io.c | 27 | ||||
| -rwxr-xr-x | tests/qemu-iotests/154 | 4 | ||||
| -rw-r--r-- | tests/qemu-iotests/154.out | 12 |
3 files changed, 28 insertions, 15 deletions
diff --git a/block/io.c b/block/io.c index 7e6abef269..2de7c77983 100644 --- a/block/io.c +++ b/block/io.c @@ -1803,10 +1803,13 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, /* Ignore errors. This is just providing extra information, it * is useful but not necessary. */ - if (!file_pnum) { - /* !file_pnum indicates an offset at or beyond the EOF; it is - * perfectly valid for the format block driver to point to such - * offsets, so catch it and mark everything as zero */ + if (ret2 & BDRV_BLOCK_EOF && + (!file_pnum || ret2 & BDRV_BLOCK_ZERO)) { + /* + * It is valid for the format block driver to read + * beyond the end of the underlying file's current + * size; such areas read as zero. + */ ret |= BDRV_BLOCK_ZERO; } else { /* Limit request to the range reported by the protocol driver */ @@ -1833,16 +1836,30 @@ static int64_t coroutine_fn bdrv_co_get_block_status_above(BlockDriverState *bs, { BlockDriverState *p; int64_t ret = 0; + bool first = true; assert(bs != base); for (p = bs; p != base; p = backing_bs(p)) { ret = bdrv_co_get_block_status(p, sector_num, nb_sectors, pnum, file); - if (ret < 0 || ret & BDRV_BLOCK_ALLOCATED) { + if (ret < 0) { + break; + } + if (ret & BDRV_BLOCK_ZERO && ret & BDRV_BLOCK_EOF && !first) { + /* + * Reading beyond the end of the file continues to read + * zeroes, but we can only widen the result to the + * unallocated length we learned from an earlier + * iteration. + */ + *pnum = nb_sectors; + } + if (ret & (BDRV_BLOCK_ZERO | BDRV_BLOCK_DATA)) { break; } /* [sector_num, pnum] unallocated on this layer, which could be only * the first part of [sector_num, nb_sectors]. */ nb_sectors = MIN(nb_sectors, *pnum); + first = false; } return ret; } diff --git a/tests/qemu-iotests/154 b/tests/qemu-iotests/154 index dd8a426dad..fde03b0dc8 100755 --- a/tests/qemu-iotests/154 +++ b/tests/qemu-iotests/154 @@ -334,8 +334,6 @@ $QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io $QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map # Repeat with backing file holding unallocated cluster. -# TODO: Note that this forces an allocation, because we aren't yet able to -# quickly detect that reads beyond EOF of the backing file are always zero CLUSTER_SIZE=2048 TEST_IMG="$TEST_IMG.base" _make_test_img $((size + 1024)) # Write at the front: sector-wise, the request is: @@ -371,8 +369,6 @@ $QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io $QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map # Repeat with backing file holding zero'd cluster -# TODO: Note that this forces an allocation, because we aren't yet able to -# quickly detect that reads beyond EOF of the backing file are always zero $QEMU_IO -c "write -z $size 512" "$TEST_IMG.base" | _filter_qemu_io # Write at the front: sector-wise, the request is: diff --git a/tests/qemu-iotests/154.out b/tests/qemu-iotests/154.out index d8485eeff2..fa3673317f 100644 --- a/tests/qemu-iotests/154.out +++ b/tests/qemu-iotests/154.out @@ -310,19 +310,19 @@ wrote 512/512 bytes at offset 134217728 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) 2048/2048 bytes allocated at offset 128 MiB [{ "start": 0, "length": 134217728, "depth": 1, "zero": true, "data": false}, -{ "start": 134217728, "length": 2048, "depth": 0, "zero": false, "data": true, "offset": OFFSET}] +{ "start": 134217728, "length": 2048, "depth": 0, "zero": true, "data": false}] Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134219776 backing_file=TEST_DIR/t.IMGFMT.base wrote 512/512 bytes at offset 134219264 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) 2048/2048 bytes allocated at offset 128 MiB [{ "start": 0, "length": 134217728, "depth": 1, "zero": true, "data": false}, -{ "start": 134217728, "length": 2048, "depth": 0, "zero": false, "data": true, "offset": OFFSET}] +{ "start": 134217728, "length": 2048, "depth": 0, "zero": true, "data": false}] Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134219776 backing_file=TEST_DIR/t.IMGFMT.base wrote 1024/1024 bytes at offset 134218240 1 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) 2048/2048 bytes allocated at offset 128 MiB [{ "start": 0, "length": 134217728, "depth": 1, "zero": true, "data": false}, -{ "start": 134217728, "length": 2048, "depth": 0, "zero": false, "data": true, "offset": OFFSET}] +{ "start": 134217728, "length": 2048, "depth": 0, "zero": true, "data": false}] Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134219776 backing_file=TEST_DIR/t.IMGFMT.base wrote 2048/2048 bytes at offset 134217728 2 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) @@ -336,19 +336,19 @@ wrote 512/512 bytes at offset 134217728 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) 2048/2048 bytes allocated at offset 128 MiB [{ "start": 0, "length": 134217728, "depth": 1, "zero": true, "data": false}, -{ "start": 134217728, "length": 2048, "depth": 0, "zero": false, "data": true, "offset": OFFSET}] +{ "start": 134217728, "length": 2048, "depth": 0, "zero": true, "data": false}] Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134219776 backing_file=TEST_DIR/t.IMGFMT.base wrote 512/512 bytes at offset 134219264 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) 2048/2048 bytes allocated at offset 128 MiB [{ "start": 0, "length": 134217728, "depth": 1, "zero": true, "data": false}, -{ "start": 134217728, "length": 2048, "depth": 0, "zero": false, "data": true, "offset": OFFSET}] +{ "start": 134217728, "length": 2048, "depth": 0, "zero": true, "data": false}] Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134219776 backing_file=TEST_DIR/t.IMGFMT.base wrote 1024/1024 bytes at offset 134218240 1 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) 2048/2048 bytes allocated at offset 128 MiB [{ "start": 0, "length": 134217728, "depth": 1, "zero": true, "data": false}, -{ "start": 134217728, "length": 2048, "depth": 0, "zero": false, "data": true, "offset": OFFSET}] +{ "start": 134217728, "length": 2048, "depth": 0, "zero": true, "data": false}] Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134219776 backing_file=TEST_DIR/t.IMGFMT.base wrote 2048/2048 bytes at offset 134217728 2 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) |