From 69f47505ee66afaa513305de0c1895a224e52c45 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Mon, 8 Apr 2019 19:26:17 +0300 Subject: [PATCH] block: avoid recursive block_status call if possible drv_co_block_status digs bs->file for additional, more accurate search for hole inside region, reported as DATA by bs since 5daa74a6ebc. This accuracy is not free: assume we have qcow2 disk. Actually, qcow2 knows, where are holes and where is data. But every block_status request calls lseek additionally. Assume a big disk, full of data, in any iterative copying block job (or img convert) we'll call lseek(HOLE) on every iteration, and each of these lseeks will have to iterate through all metadata up to the end of file. It's obviously ineffective behavior. And for many scenarios we don't need this lseek at all. However, lseek is needed when we have metadata-preallocated image. So, let's detect metadata-preallocation case and don't dig qcow2's protocol file in other cases. The idea is to compare allocation size in POV of filesystem with allocations size in POV of Qcow2 (by refcounts). If allocation in fs is significantly lower, consider it as metadata-preallocation case. 102 iotest changed, as our detector can't detect shrinked file as metadata-preallocation, which don't seem to be wrong, as with metadata preallocation we always have valid file length. Two other iotests have a slight change in their QMP output sequence: Active 'block-commit' returns earlier because the job coroutine yields earlier on a blocking operation. This operation is loading the refcount blocks in qcow2_detect_metadata_preallocation(). Suggested-by: Denis V. Lunev Signed-off-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Kevin Wolf --- block/io.c | 9 ++++++++- block/qcow2-refcount.c | 32 ++++++++++++++++++++++++++++++++ block/qcow2.c | 11 +++++++++++ block/qcow2.h | 4 ++++ include/block/block.h | 8 +++++++- tests/qemu-iotests/102 | 2 +- tests/qemu-iotests/102.out | 3 ++- tests/qemu-iotests/141.out | 2 +- tests/qemu-iotests/144.out | 2 +- 9 files changed, 67 insertions(+), 6 deletions(-) diff --git a/block/io.c b/block/io.c index 3134a60a48..150358c3b1 100644 --- a/block/io.c +++ b/block/io.c @@ -2092,6 +2092,12 @@ static int coroutine_fn bdrv_co_block_status(BlockDriverState *bs, */ assert(*pnum && QEMU_IS_ALIGNED(*pnum, align) && align > offset - aligned_offset); + if (ret & BDRV_BLOCK_RECURSE) { + assert(ret & BDRV_BLOCK_DATA); + assert(ret & BDRV_BLOCK_OFFSET_VALID); + assert(!(ret & BDRV_BLOCK_ZERO)); + } + *pnum -= offset - aligned_offset; if (*pnum > bytes) { *pnum = bytes; @@ -2122,7 +2128,8 @@ static int coroutine_fn bdrv_co_block_status(BlockDriverState *bs, } } - if (want_zero && local_file && local_file != bs && + if (want_zero && ret & BDRV_BLOCK_RECURSE && + local_file && local_file != bs && (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) && (ret & BDRV_BLOCK_OFFSET_VALID)) { int64_t file_pnum; diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 4c1794f9af..3a2c673a5e 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -3444,3 +3444,35 @@ int64_t qcow2_get_last_cluster(BlockDriverState *bs, int64_t size) "There are no references in the refcount table."); return -EIO; } + +int qcow2_detect_metadata_preallocation(BlockDriverState *bs) +{ + BDRVQcow2State *s = bs->opaque; + int64_t i, end_cluster, cluster_count = 0, threshold; + int64_t file_length, real_allocation, real_clusters; + + file_length = bdrv_getlength(bs->file->bs); + if (file_length < 0) { + return file_length; + } + + real_allocation = bdrv_get_allocated_file_size(bs->file->bs); + if (real_allocation < 0) { + return real_allocation; + } + + real_clusters = real_allocation / s->cluster_size; + threshold = MAX(real_clusters * 10 / 9, real_clusters + 2); + + end_cluster = size_to_clusters(s, file_length); + for (i = 0; i < end_cluster && cluster_count < threshold; i++) { + uint64_t refcount; + int ret = qcow2_get_refcount(bs, i, &refcount); + if (ret < 0) { + return ret; + } + cluster_count += !!refcount; + } + + return cluster_count >= threshold; +} diff --git a/block/qcow2.c b/block/qcow2.c index f2cb131048..14f914117f 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1895,6 +1895,12 @@ static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs, unsigned int bytes; int status = 0; + if (!s->metadata_preallocation_checked) { + ret = qcow2_detect_metadata_preallocation(bs); + s->metadata_preallocation = (ret == 1); + s->metadata_preallocation_checked = true; + } + bytes = MIN(INT_MAX, count); qemu_co_mutex_lock(&s->lock); ret = qcow2_get_cluster_offset(bs, offset, &bytes, &cluster_offset); @@ -1917,6 +1923,11 @@ static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs, } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { status |= BDRV_BLOCK_DATA; } + if (s->metadata_preallocation && (status & BDRV_BLOCK_DATA) && + (status & BDRV_BLOCK_OFFSET_VALID)) + { + status |= BDRV_BLOCK_RECURSE; + } return status; } diff --git a/block/qcow2.h b/block/qcow2.h index 567375e56c..fc1b0d3c1e 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -356,6 +356,9 @@ typedef struct BDRVQcow2State { int nb_threads; BdrvChild *data_file; + + bool metadata_preallocation_checked; + bool metadata_preallocation; } BDRVQcow2State; typedef struct Qcow2COWRegion { @@ -655,6 +658,7 @@ int qcow2_change_refcount_order(BlockDriverState *bs, int refcount_order, void *cb_opaque, Error **errp); int qcow2_shrink_reftable(BlockDriverState *bs); int64_t qcow2_get_last_cluster(BlockDriverState *bs, int64_t size); +int qcow2_detect_metadata_preallocation(BlockDriverState *bs); /* qcow2-cluster.c functions */ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, diff --git a/include/block/block.h b/include/block/block.h index 9b083e2bca..531cf595cf 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -156,10 +156,15 @@ typedef struct HDGeometry { * BDRV_BLOCK_EOF: the returned pnum covers through end of file for this * layer, set by block layer * - * Internal flag: + * Internal flags: * BDRV_BLOCK_RAW: for use by passthrough drivers, such as raw, to request * that the block layer recompute the answer from the returned * BDS; must be accompanied by just BDRV_BLOCK_OFFSET_VALID. + * BDRV_BLOCK_RECURSE: request that the block layer will recursively search for + * zeroes in file child of current block node inside + * returned region. Only valid together with both + * BDRV_BLOCK_DATA and BDRV_BLOCK_OFFSET_VALID. Should not + * appear with BDRV_BLOCK_ZERO. * * If BDRV_BLOCK_OFFSET_VALID is set, the map parameter represents the * host offset within the returned BDS that is allocated for the @@ -184,6 +189,7 @@ typedef struct HDGeometry { #define BDRV_BLOCK_RAW 0x08 #define BDRV_BLOCK_ALLOCATED 0x10 #define BDRV_BLOCK_EOF 0x20 +#define BDRV_BLOCK_RECURSE 0x40 #define BDRV_BLOCK_OFFSET_MASK BDRV_SECTOR_MASK typedef QSIMPLEQ_HEAD(BlockReopenQueue, BlockReopenQueueEntry) BlockReopenQueue; diff --git a/tests/qemu-iotests/102 b/tests/qemu-iotests/102 index 749ff66b8a..b898df436f 100755 --- a/tests/qemu-iotests/102 +++ b/tests/qemu-iotests/102 @@ -55,7 +55,7 @@ $QEMU_IO -c 'write 0 64k' "$TEST_IMG" | _filter_qemu_io $QEMU_IMG resize -f raw --shrink "$TEST_IMG" $((5 * 64 * 1024)) $QEMU_IO -c map "$TEST_IMG" -$QEMU_IMG map "$TEST_IMG" +$QEMU_IMG map "$TEST_IMG" | _filter_qemu_img_map echo echo '=== Testing map on an image file truncated outside of qemu ===' diff --git a/tests/qemu-iotests/102.out b/tests/qemu-iotests/102.out index 4401b08fee..cd2fdc7f96 100644 --- a/tests/qemu-iotests/102.out +++ b/tests/qemu-iotests/102.out @@ -7,7 +7,8 @@ wrote 65536/65536 bytes at offset 0 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) Image resized. 64 KiB (0x10000) bytes allocated at offset 0 bytes (0x0) -Offset Length Mapped to File +Offset Length File +0 0x10000 TEST_DIR/t.IMGFMT === Testing map on an image file truncated outside of qemu === diff --git a/tests/qemu-iotests/141.out b/tests/qemu-iotests/141.out index 41c7291258..4d71d9dcae 100644 --- a/tests/qemu-iotests/141.out +++ b/tests/qemu-iotests/141.out @@ -42,9 +42,9 @@ Formatting 'TEST_DIR/o.IMGFMT', fmt=IMGFMT size=1048576 backing_file=TEST_DIR/t. {"return": {}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "created", "id": "job0"}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "running", "id": "job0"}} +{"return": {}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "job0"}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "job0", "len": 0, "offset": 0, "speed": 0, "type": "commit"}} -{"return": {}} {"error": {"class": "GenericError", "desc": "Node 'drv0' is busy: block device is in use by block job: commit"}} {"return": {}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "job0"}} diff --git a/tests/qemu-iotests/144.out b/tests/qemu-iotests/144.out index 55299201e4..a9a8216bea 100644 --- a/tests/qemu-iotests/144.out +++ b/tests/qemu-iotests/144.out @@ -14,10 +14,10 @@ Formatting 'TEST_DIR/tmp.qcow2', fmt=qcow2 size=536870912 backing_file=TEST_DIR/ {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "created", "id": "virtio0"}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "running", "id": "virtio0"}} +{"return": {}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "ready", "id": "virtio0"}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_READY", "data": {"device": "virtio0", "len": 0, "offset": 0, "speed": 0, "type": "commit"}} {"return": {}} -{"return": {}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "virtio0"}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "virtio0"}} {"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "virtio0", "len": 0, "offset": 0, "speed": 0, "type": "commit"}}