diff options
| -rw-r--r-- | block/io.c | 30 | ||||
| -rw-r--r-- | tests/qemu-iotests/154.out | 18 |
2 files changed, 29 insertions, 19 deletions
diff --git a/block/io.c b/block/io.c index 6070e773b7..c73be55f86 100644 --- a/block/io.c +++ b/block/io.c @@ -1118,28 +1118,32 @@ static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, struct iovec iov = {0}; int ret = 0; bool need_flush = false; + int head = 0; + int tail = 0; int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_write_zeroes, BDRV_REQUEST_MAX_SECTORS); + if (bs->bl.write_zeroes_alignment) { + assert(is_power_of_2(bs->bl.write_zeroes_alignment)); + head = sector_num & (bs->bl.write_zeroes_alignment - 1); + tail = (sector_num + nb_sectors) & (bs->bl.write_zeroes_alignment - 1); + max_write_zeroes &= ~(bs->bl.write_zeroes_alignment - 1); + } while (nb_sectors > 0 && !ret) { int num = nb_sectors; /* Align request. Block drivers can expect the "bulk" of the request - * to be aligned. + * to be aligned, and that unaligned requests do not cross cluster + * boundaries. */ - if (bs->bl.write_zeroes_alignment - && num > bs->bl.write_zeroes_alignment) { - if (sector_num % bs->bl.write_zeroes_alignment != 0) { - /* Make a small request up to the first aligned sector. */ - num = bs->bl.write_zeroes_alignment; - num -= sector_num % bs->bl.write_zeroes_alignment; - } else if ((sector_num + num) % bs->bl.write_zeroes_alignment != 0) { - /* Shorten the request to the last aligned sector. num cannot - * underflow because num > bs->bl.write_zeroes_alignment. - */ - num -= (sector_num + num) % bs->bl.write_zeroes_alignment; - } + if (head) { + /* Make a small request up to the first aligned sector. */ + num = MIN(nb_sectors, bs->bl.write_zeroes_alignment - head); + head = 0; + } else if (tail && num > bs->bl.write_zeroes_alignment) { + /* Shorten the request to the last aligned sector. */ + num -= tail; } /* limit request size */ diff --git a/tests/qemu-iotests/154.out b/tests/qemu-iotests/154.out index 8946b734ac..b9d27c501a 100644 --- a/tests/qemu-iotests/154.out +++ b/tests/qemu-iotests/154.out @@ -106,11 +106,14 @@ read 1024/1024 bytes at offset 67584 read 5120/5120 bytes at offset 68608 5 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) [{ "start": 0, "length": 32768, "depth": 1, "zero": true, "data": false}, -{ "start": 32768, "length": 8192, "depth": 0, "zero": false, "data": true, "offset": 20480}, +{ "start": 32768, "length": 4096, "depth": 0, "zero": false, "data": true, "offset": 20480}, +{ "start": 36864, "length": 4096, "depth": 0, "zero": true, "data": false}, { "start": 40960, "length": 8192, "depth": 1, "zero": true, "data": false}, -{ "start": 49152, "length": 8192, "depth": 0, "zero": false, "data": true, "offset": 28672}, +{ "start": 49152, "length": 4096, "depth": 0, "zero": false, "data": true, "offset": 24576}, +{ "start": 53248, "length": 4096, "depth": 0, "zero": true, "data": false}, { "start": 57344, "length": 8192, "depth": 1, "zero": true, "data": false}, -{ "start": 65536, "length": 8192, "depth": 0, "zero": false, "data": true, "offset": 36864}, +{ "start": 65536, "length": 4096, "depth": 0, "zero": false, "data": true, "offset": 28672}, +{ "start": 69632, "length": 4096, "depth": 0, "zero": true, "data": false}, { "start": 73728, "length": 134144000, "depth": 1, "zero": true, "data": false}] == spanning two clusters, non-zero after request == @@ -145,11 +148,14 @@ read 7168/7168 bytes at offset 65536 read 1024/1024 bytes at offset 72704 1 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) [{ "start": 0, "length": 32768, "depth": 1, "zero": true, "data": false}, -{ "start": 32768, "length": 8192, "depth": 0, "zero": false, "data": true, "offset": 20480}, +{ "start": 32768, "length": 4096, "depth": 0, "zero": true, "data": false}, +{ "start": 36864, "length": 4096, "depth": 0, "zero": false, "data": true, "offset": 20480}, { "start": 40960, "length": 8192, "depth": 1, "zero": true, "data": false}, -{ "start": 49152, "length": 8192, "depth": 0, "zero": false, "data": true, "offset": 28672}, +{ "start": 49152, "length": 4096, "depth": 0, "zero": true, "data": false}, +{ "start": 53248, "length": 4096, "depth": 0, "zero": false, "data": true, "offset": 24576}, { "start": 57344, "length": 8192, "depth": 1, "zero": true, "data": false}, -{ "start": 65536, "length": 8192, "depth": 0, "zero": false, "data": true, "offset": 36864}, +{ "start": 65536, "length": 4096, "depth": 0, "zero": true, "data": false}, +{ "start": 69632, "length": 4096, "depth": 0, "zero": false, "data": true, "offset": 28672}, { "start": 73728, "length": 134144000, "depth": 1, "zero": true, "data": false}] == spanning two clusters, partially overwriting backing file == |