* [PATCH v6 0/5] fix & merge block_status_above and is_allocated_above
@ 2020-09-16 12:20 Vladimir Sementsov-Ogievskiy
2020-09-16 12:20 ` [PATCH v6 1/5] block/io: fix bdrv_co_block_status_above Vladimir Sementsov-Ogievskiy
` (4 more replies)
0 siblings, 5 replies; 14+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2020-09-16 12:20 UTC (permalink / raw
To: qemu-block
Cc: qemu-devel, fam, stefanha, mreitz, kwolf, eblake, den, vsementsov
Hi all!
These series are here to address the following problem:
block-status-above functions may consider space after EOF of
intermediate backing files as unallocated, which is wrong, as these
backing files are the reason of producing zeroes, we never go further by
backing chain after a short backing file. So, if such short-backing file
is _inside_ requested sub-chain of the backing chain, we should never
report space after its EOF as unallocated.
See patches 01,04,05 for details.
Note, that this series leaves for another day the general problem
around block-status: misuse of BDRV_BLOCK_ALLOCATED as is-fs-allocated
vs go-to-backing.
Audit for this problem is done here:
"backing chain & block status & filters"
https://lists.gnu.org/archive/html/qemu-devel/2020-04/msg04706.html
And I'm going to prepare series to address this problem.
Also, get_block_status func have same disease, but remains unfixed here:
I want to make separate series for it.
v6:
01: handle EOF better, don't merge reported ZERO-es with automatic after-EOF zeroes,
handle first layer out of the loop to make code read simpler. Drop r-b.
02: rebase on 01
05: update test output for extended l2 and backing file format, keep r-b
Based on series "PATCH v8 0/7] coroutines: generate wrapper code" or
in other words:
Based-on: <20200915164411.20590-1-vsementsov@virtuozzo.com>
Vladimir Sementsov-Ogievskiy (5):
block/io: fix bdrv_co_block_status_above
block/io: bdrv_common_block_status_above: support include_base
block/io: bdrv_common_block_status_above: support bs == base
block/io: fix bdrv_is_allocated_above
iotests: add commit top->base cases to 274
block/coroutines.h | 2 +
block/io.c | 126 +++++++++++++++++++++----------------
block/qcow2.c | 16 ++++-
tests/qemu-iotests/274 | 20 ++++++
tests/qemu-iotests/274.out | 68 ++++++++++++++++++++
5 files changed, 175 insertions(+), 57 deletions(-)
--
2.21.3
^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH v6 1/5] block/io: fix bdrv_co_block_status_above
2020-09-16 12:20 [PATCH v6 0/5] fix & merge block_status_above and is_allocated_above Vladimir Sementsov-Ogievskiy
@ 2020-09-16 12:20 ` Vladimir Sementsov-Ogievskiy
2020-09-24 16:20 ` Alberto Garcia
2020-09-16 12:20 ` [PATCH v6 2/5] block/io: bdrv_common_block_status_above: support include_base Vladimir Sementsov-Ogievskiy
` (3 subsequent siblings)
4 siblings, 1 reply; 14+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2020-09-16 12:20 UTC (permalink / raw
To: qemu-block
Cc: qemu-devel, fam, stefanha, mreitz, kwolf, eblake, den, vsementsov
bdrv_co_block_status_above has several design problems with handling
short backing files:
1. With want_zeros=true, it may return ret with BDRV_BLOCK_ZERO but
without BDRV_BLOCK_ALLOCATED flag, when actually short backing file
which produces these after-EOF zeros is inside requested backing
sequence.
2. With want_zero=false, it may return pnum=0 prior to actual EOF,
because of EOF of short backing file.
Fix these things, making logic about short backing files clearer.
With fixed bdrv_block_status_above we also have to improve is_zero in
qcow2 code, otherwise iotest 154 will fail, because with this patch we
stop to merge zeros of different types (produced by fully unallocated
in the whole backing chain regions vs produced by short backing files).
Note also, that this patch leaves for another day the general problem
around block-status: misuse of BDRV_BLOCK_ALLOCATED as is-fs-allocated
vs go-to-backing.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
block/io.c | 66 ++++++++++++++++++++++++++++++++++++++++-----------
block/qcow2.c | 16 +++++++++++--
2 files changed, 66 insertions(+), 16 deletions(-)
diff --git a/block/io.c b/block/io.c
index 84f82bc069..e381d2da35 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2366,34 +2366,72 @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
int64_t *map,
BlockDriverState **file)
{
+ int ret;
BlockDriverState *p;
- int ret = 0;
- bool first = true;
+ int64_t eof = 0;
assert(bs != base);
- for (p = bs; p != base; p = backing_bs(p)) {
+
+ ret = bdrv_co_block_status(bs, want_zero, offset, bytes, pnum, map, file);
+ if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED) {
+ return ret;
+ }
+
+ if (ret & BDRV_BLOCK_EOF) {
+ eof = offset + *pnum;
+ }
+
+ assert(*pnum <= bytes);
+ bytes = *pnum;
+
+ for (p = backing_bs(bs); p != base; p = backing_bs(p)) {
ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map,
file);
if (ret < 0) {
- break;
+ return ret;
}
- if (ret & BDRV_BLOCK_ZERO && ret & BDRV_BLOCK_EOF && !first) {
+ if (*pnum == 0) {
/*
- * 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.
+ * The top layer deferred to this layer, and because this layer is
+ * short, any zeroes that we synthesize beyond EOF behave as if they
+ * were allocated at this layer.
+ *
+ * We don't include BDRV_BLOCK_EOF into ret, as upper layer may be
+ * larger. We'll add BDRV_BLOCK_EOF if needed at function end, see
+ * below.
*/
+ assert(ret & BDRV_BLOCK_EOF);
*pnum = bytes;
+ if (file) {
+ *file = p;
+ }
+ ret = BDRV_BLOCK_ZERO | BDRV_BLOCK_ALLOCATED;
+ break;
}
- if (ret & (BDRV_BLOCK_ZERO | BDRV_BLOCK_DATA)) {
+ if (ret & BDRV_BLOCK_ALLOCATED) {
+ /*
+ * We've found the node and the status, we must break.
+ *
+ * Drop BDRV_BLOCK_EOF, as it's not for upper layer, which may be
+ * larger. We'll add BDRV_BLOCK_EOF if needed at function end, see
+ * below.
+ */
+ ret &= ~BDRV_BLOCK_EOF;
break;
}
- /* [offset, pnum] unallocated on this layer, which could be only
- * the first part of [offset, bytes]. */
- bytes = MIN(bytes, *pnum);
- first = false;
+
+ /*
+ * OK, [offset, offset + *pnum) region is unallocated on this layer,
+ * let's continue the diving.
+ */
+ assert(*pnum <= bytes);
+ bytes = *pnum;
}
+
+ if (offset + *pnum == eof) {
+ ret |= BDRV_BLOCK_EOF;
+ }
+
return ret;
}
diff --git a/block/qcow2.c b/block/qcow2.c
index da56b1a4df..15ba0ce81a 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3872,8 +3872,20 @@ static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes)
if (!bytes) {
return true;
}
- res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL);
- return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes;
+
+ /*
+ * bdrv_block_status_above doesn't merge different types of zeros, for
+ * example, zeros which come from the region which is unallocated in
+ * the whole backing chain, and zeros which comes because of a short
+ * backing file. So, we need a loop.
+ */
+ do {
+ res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL);
+ offset += nr;
+ bytes -= nr;
+ } while (res >= 0 && (res & BDRV_BLOCK_ZERO) && nr && bytes);
+
+ return res >= 0 && (res & BDRV_BLOCK_ZERO) && bytes == 0;
}
static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
--
2.21.3
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH v6 2/5] block/io: bdrv_common_block_status_above: support include_base
2020-09-16 12:20 [PATCH v6 0/5] fix & merge block_status_above and is_allocated_above Vladimir Sementsov-Ogievskiy
2020-09-16 12:20 ` [PATCH v6 1/5] block/io: fix bdrv_co_block_status_above Vladimir Sementsov-Ogievskiy
@ 2020-09-16 12:20 ` Vladimir Sementsov-Ogievskiy
2020-09-23 16:18 ` Alberto Garcia
2020-09-23 17:49 ` Alberto Garcia
2020-09-16 12:20 ` [PATCH v6 3/5] block/io: bdrv_common_block_status_above: support bs == base Vladimir Sementsov-Ogievskiy
` (2 subsequent siblings)
4 siblings, 2 replies; 14+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2020-09-16 12:20 UTC (permalink / raw
To: qemu-block
Cc: qemu-devel, fam, stefanha, mreitz, kwolf, eblake, den, vsementsov
In order to reuse bdrv_common_block_status_above in
bdrv_is_allocated_above, let's support include_base parameter.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
block/coroutines.h | 2 ++
block/io.c | 17 ++++++++++++-----
2 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/block/coroutines.h b/block/coroutines.h
index f69179f5ef..1cb3128b94 100644
--- a/block/coroutines.h
+++ b/block/coroutines.h
@@ -41,6 +41,7 @@ bdrv_pwritev(BdrvChild *child, int64_t offset, unsigned int bytes,
int coroutine_fn
bdrv_co_common_block_status_above(BlockDriverState *bs,
BlockDriverState *base,
+ bool include_base,
bool want_zero,
int64_t offset,
int64_t bytes,
@@ -50,6 +51,7 @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
int generated_co_wrapper
bdrv_common_block_status_above(BlockDriverState *bs,
BlockDriverState *base,
+ bool include_base,
bool want_zero,
int64_t offset,
int64_t bytes,
diff --git a/block/io.c b/block/io.c
index e381d2da35..0cc2dd7a3e 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2359,6 +2359,7 @@ early_out:
int coroutine_fn
bdrv_co_common_block_status_above(BlockDriverState *bs,
BlockDriverState *base,
+ bool include_base,
bool want_zero,
int64_t offset,
int64_t bytes,
@@ -2370,10 +2371,11 @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
BlockDriverState *p;
int64_t eof = 0;
- assert(bs != base);
+ assert(include_base || bs != base);
+ assert(!include_base || base); /* Can't include NULL base */
ret = bdrv_co_block_status(bs, want_zero, offset, bytes, pnum, map, file);
- if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED) {
+ if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED || bs == base) {
return ret;
}
@@ -2384,7 +2386,7 @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
assert(*pnum <= bytes);
bytes = *pnum;
- for (p = backing_bs(bs); p != base; p = backing_bs(p)) {
+ for (p = backing_bs(bs); include_base || p != base; p = backing_bs(p)) {
ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map,
file);
if (ret < 0) {
@@ -2420,6 +2422,11 @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
break;
}
+ if (p == base) {
+ assert(include_base);
+ break;
+ }
+
/*
* OK, [offset, offset + *pnum) region is unallocated on this layer,
* let's continue the diving.
@@ -2439,7 +2446,7 @@ int bdrv_block_status_above(BlockDriverState *bs, BlockDriverState *base,
int64_t offset, int64_t bytes, int64_t *pnum,
int64_t *map, BlockDriverState **file)
{
- return bdrv_common_block_status_above(bs, base, true, offset, bytes,
+ return bdrv_common_block_status_above(bs, base, false, true, offset, bytes,
pnum, map, file);
}
@@ -2456,7 +2463,7 @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,
int ret;
int64_t dummy;
- ret = bdrv_common_block_status_above(bs, backing_bs(bs), false, offset,
+ ret = bdrv_common_block_status_above(bs, bs, true, false, offset,
bytes, pnum ? pnum : &dummy, NULL,
NULL);
if (ret < 0) {
--
2.21.3
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH v6 3/5] block/io: bdrv_common_block_status_above: support bs == base
2020-09-16 12:20 [PATCH v6 0/5] fix & merge block_status_above and is_allocated_above Vladimir Sementsov-Ogievskiy
2020-09-16 12:20 ` [PATCH v6 1/5] block/io: fix bdrv_co_block_status_above Vladimir Sementsov-Ogievskiy
2020-09-16 12:20 ` [PATCH v6 2/5] block/io: bdrv_common_block_status_above: support include_base Vladimir Sementsov-Ogievskiy
@ 2020-09-16 12:20 ` Vladimir Sementsov-Ogievskiy
2020-09-23 16:22 ` Alberto Garcia
2020-09-16 12:20 ` [PATCH v6 4/5] block/io: fix bdrv_is_allocated_above Vladimir Sementsov-Ogievskiy
2020-09-16 12:20 ` [PATCH v6 5/5] iotests: add commit top->base cases to 274 Vladimir Sementsov-Ogievskiy
4 siblings, 1 reply; 14+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2020-09-16 12:20 UTC (permalink / raw
To: qemu-block
Cc: qemu-devel, fam, stefanha, mreitz, kwolf, eblake, den, vsementsov
We are going to reuse bdrv_common_block_status_above in
bdrv_is_allocated_above. bdrv_is_allocated_above may be called with
include_base == false and still bs == base (for ex. from img_rebase()).
So, support this corner case.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
block/io.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/block/io.c b/block/io.c
index 0cc2dd7a3e..d864d035ac 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2371,9 +2371,13 @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
BlockDriverState *p;
int64_t eof = 0;
- assert(include_base || bs != base);
assert(!include_base || base); /* Can't include NULL base */
+ if (!include_base && bs == base) {
+ *pnum = bytes;
+ return 0;
+ }
+
ret = bdrv_co_block_status(bs, want_zero, offset, bytes, pnum, map, file);
if (ret < 0 || *pnum == 0 || ret & BDRV_BLOCK_ALLOCATED || bs == base) {
return ret;
--
2.21.3
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH v6 4/5] block/io: fix bdrv_is_allocated_above
2020-09-16 12:20 [PATCH v6 0/5] fix & merge block_status_above and is_allocated_above Vladimir Sementsov-Ogievskiy
` (2 preceding siblings ...)
2020-09-16 12:20 ` [PATCH v6 3/5] block/io: bdrv_common_block_status_above: support bs == base Vladimir Sementsov-Ogievskiy
@ 2020-09-16 12:20 ` Vladimir Sementsov-Ogievskiy
2020-09-24 16:21 ` Alberto Garcia
2020-09-16 12:20 ` [PATCH v6 5/5] iotests: add commit top->base cases to 274 Vladimir Sementsov-Ogievskiy
4 siblings, 1 reply; 14+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2020-09-16 12:20 UTC (permalink / raw
To: qemu-block
Cc: qemu-devel, fam, stefanha, mreitz, kwolf, eblake, den, vsementsov
bdrv_is_allocated_above wrongly handles short backing files: it reports
after-EOF space as UNALLOCATED which is wrong, as on read the data is
generated on the level of short backing file (if all overlays has
unallocated area at that place).
Reusing bdrv_common_block_status_above fixes the issue and unifies code
path.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
block/io.c | 43 +++++--------------------------------------
1 file changed, 5 insertions(+), 38 deletions(-)
diff --git a/block/io.c b/block/io.c
index d864d035ac..95b86429ca 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2491,52 +2491,19 @@ int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,
* at 'offset + *pnum' may return the same allocation status (in other
* words, the result is not necessarily the maximum possible range);
* but 'pnum' will only be 0 when end of file is reached.
- *
*/
int bdrv_is_allocated_above(BlockDriverState *top,
BlockDriverState *base,
bool include_base, int64_t offset,
int64_t bytes, int64_t *pnum)
{
- BlockDriverState *intermediate;
- int ret;
- int64_t n = bytes;
-
- assert(base || !include_base);
-
- intermediate = top;
- while (include_base || intermediate != base) {
- int64_t pnum_inter;
- int64_t size_inter;
-
- assert(intermediate);
- ret = bdrv_is_allocated(intermediate, offset, bytes, &pnum_inter);
- if (ret < 0) {
- return ret;
- }
- if (ret) {
- *pnum = pnum_inter;
- return 1;
- }
-
- size_inter = bdrv_getlength(intermediate);
- if (size_inter < 0) {
- return size_inter;
- }
- if (n > pnum_inter &&
- (intermediate == top || offset + pnum_inter < size_inter)) {
- n = pnum_inter;
- }
-
- if (intermediate == base) {
- break;
- }
-
- intermediate = backing_bs(intermediate);
+ int ret = bdrv_common_block_status_above(top, base, include_base, false,
+ offset, bytes, pnum, NULL, NULL);
+ if (ret < 0) {
+ return ret;
}
- *pnum = n;
- return 0;
+ return !!(ret & BDRV_BLOCK_ALLOCATED);
}
int coroutine_fn
--
2.21.3
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH v6 5/5] iotests: add commit top->base cases to 274
2020-09-16 12:20 [PATCH v6 0/5] fix & merge block_status_above and is_allocated_above Vladimir Sementsov-Ogievskiy
` (3 preceding siblings ...)
2020-09-16 12:20 ` [PATCH v6 4/5] block/io: fix bdrv_is_allocated_above Vladimir Sementsov-Ogievskiy
@ 2020-09-16 12:20 ` Vladimir Sementsov-Ogievskiy
2020-09-24 16:24 ` Alberto Garcia
4 siblings, 1 reply; 14+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2020-09-16 12:20 UTC (permalink / raw
To: qemu-block
Cc: qemu-devel, fam, stefanha, mreitz, kwolf, eblake, den, vsementsov
These cases are fixed by previous patches around block_status and
is_allocated.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
tests/qemu-iotests/274 | 20 +++++++++++
tests/qemu-iotests/274.out | 68 ++++++++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+)
diff --git a/tests/qemu-iotests/274 b/tests/qemu-iotests/274
index d4571c5465..76b1ba6a52 100755
--- a/tests/qemu-iotests/274
+++ b/tests/qemu-iotests/274
@@ -115,6 +115,26 @@ with iotests.FilePath('base') as base, \
iotests.qemu_io_log('-c', 'read -P 1 0 %d' % size_short, mid)
iotests.qemu_io_log('-c', 'read -P 0 %d %d' % (size_short, size_diff), mid)
+ iotests.log('=== Testing qemu-img commit (top -> base) ===')
+
+ create_chain()
+ iotests.qemu_img_log('commit', '-b', base, top)
+ iotests.img_info_log(base)
+ iotests.qemu_io_log('-c', 'read -P 1 0 %d' % size_short, base)
+ iotests.qemu_io_log('-c', 'read -P 0 %d %d' % (size_short, size_diff), base)
+
+ iotests.log('=== Testing QMP active commit (top -> base) ===')
+
+ create_chain()
+ with create_vm() as vm:
+ vm.launch()
+ vm.qmp_log('block-commit', device='top', base_node='base',
+ job_id='job0', auto_dismiss=False)
+ vm.run_job('job0', wait=5)
+
+ iotests.img_info_log(mid)
+ iotests.qemu_io_log('-c', 'read -P 1 0 %d' % size_short, base)
+ iotests.qemu_io_log('-c', 'read -P 0 %d %d' % (size_short, size_diff), base)
iotests.log('== Resize tests ==')
diff --git a/tests/qemu-iotests/274.out b/tests/qemu-iotests/274.out
index bf5abd4c10..cfe17a8659 100644
--- a/tests/qemu-iotests/274.out
+++ b/tests/qemu-iotests/274.out
@@ -135,6 +135,74 @@ read 1048576/1048576 bytes at offset 0
read 1048576/1048576 bytes at offset 1048576
1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+=== Testing qemu-img commit (top -> base) ===
+Formatting 'TEST_DIR/PID-base', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=2097152 lazy_refcounts=off refcount_bits=16
+
+Formatting 'TEST_DIR/PID-mid', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=1048576 backing_file=TEST_DIR/PID-base backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
+
+Formatting 'TEST_DIR/PID-top', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=2097152 backing_file=TEST_DIR/PID-mid backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
+
+wrote 2097152/2097152 bytes at offset 0
+2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+Image committed.
+
+image: TEST_IMG
+file format: IMGFMT
+virtual size: 2 MiB (2097152 bytes)
+cluster_size: 65536
+Format specific information:
+ compat: 1.1
+ compression type: zlib
+ lazy refcounts: false
+ refcount bits: 16
+ corrupt: false
+ extended l2: false
+
+read 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+read 1048576/1048576 bytes at offset 1048576
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+=== Testing QMP active commit (top -> base) ===
+Formatting 'TEST_DIR/PID-base', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=2097152 lazy_refcounts=off refcount_bits=16
+
+Formatting 'TEST_DIR/PID-mid', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=1048576 backing_file=TEST_DIR/PID-base backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
+
+Formatting 'TEST_DIR/PID-top', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=2097152 backing_file=TEST_DIR/PID-mid backing_fmt=qcow2 lazy_refcounts=off refcount_bits=16
+
+wrote 2097152/2097152 bytes at offset 0
+2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+{"execute": "block-commit", "arguments": {"auto-dismiss": false, "base-node": "base", "device": "top", "job-id": "job0"}}
+{"return": {}}
+{"execute": "job-complete", "arguments": {"id": "job0"}}
+{"return": {}}
+{"data": {"device": "job0", "len": 1048576, "offset": 1048576, "speed": 0, "type": "commit"}, "event": "BLOCK_JOB_READY", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+{"data": {"device": "job0", "len": 1048576, "offset": 1048576, "speed": 0, "type": "commit"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+{"execute": "job-dismiss", "arguments": {"id": "job0"}}
+{"return": {}}
+image: TEST_IMG
+file format: IMGFMT
+virtual size: 1 MiB (1048576 bytes)
+cluster_size: 65536
+backing file: TEST_DIR/PID-base
+backing file format: IMGFMT
+Format specific information:
+ compat: 1.1
+ compression type: zlib
+ lazy refcounts: false
+ refcount bits: 16
+ corrupt: false
+ extended l2: false
+
+read 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+read 1048576/1048576 bytes at offset 1048576
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
== Resize tests ==
=== preallocation=off ===
Formatting 'TEST_DIR/PID-base', fmt=qcow2 cluster_size=65536 extended_l2=off compression_type=zlib size=6442450944 lazy_refcounts=off refcount_bits=16
--
2.21.3
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH v6 2/5] block/io: bdrv_common_block_status_above: support include_base
2020-09-16 12:20 ` [PATCH v6 2/5] block/io: bdrv_common_block_status_above: support include_base Vladimir Sementsov-Ogievskiy
@ 2020-09-23 16:18 ` Alberto Garcia
2020-09-23 17:11 ` Vladimir Sementsov-Ogievskiy
2020-09-23 17:49 ` Alberto Garcia
1 sibling, 1 reply; 14+ messages in thread
From: Alberto Garcia @ 2020-09-23 16:18 UTC (permalink / raw
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: fam, kwolf, vsementsov, qemu-devel, mreitz, stefanha, den
On Wed 16 Sep 2020 02:20:05 PM CEST, Vladimir Sementsov-Ogievskiy wrote:
> - for (p = backing_bs(bs); p != base; p = backing_bs(p)) {
> + for (p = backing_bs(bs); include_base || p != base; p = backing_bs(p)) {
> ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map,
> file);
> if (ret < 0) {
> @@ -2420,6 +2422,11 @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
> break;
> }
>
> + if (p == base) {
> + assert(include_base);
> + break;
> + }
> +
Another option is something like:
BlockDriverState *last_bs = include_base ? base : backing_bs(base);
and you get a simpler 'for' loop.
But why do we need include_base at all? Can't the caller just pass
backing_bs(base) instead? I'm talking also about the existing case of
bdrv_is_allocated_above().
Berto
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v6 3/5] block/io: bdrv_common_block_status_above: support bs == base
2020-09-16 12:20 ` [PATCH v6 3/5] block/io: bdrv_common_block_status_above: support bs == base Vladimir Sementsov-Ogievskiy
@ 2020-09-23 16:22 ` Alberto Garcia
0 siblings, 0 replies; 14+ messages in thread
From: Alberto Garcia @ 2020-09-23 16:22 UTC (permalink / raw
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: fam, kwolf, vsementsov, qemu-devel, mreitz, stefanha, den
On Wed 16 Sep 2020 02:20:06 PM CEST, Vladimir Sementsov-Ogievskiy wrote:
> We are going to reuse bdrv_common_block_status_above in
> bdrv_is_allocated_above. bdrv_is_allocated_above may be called with
> include_base == false and still bs == base (for ex. from img_rebase()).
>
> So, support this corner case.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
(my question about include_base remains, but otherwise this patch is
correct)
Berto
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v6 2/5] block/io: bdrv_common_block_status_above: support include_base
2020-09-23 16:18 ` Alberto Garcia
@ 2020-09-23 17:11 ` Vladimir Sementsov-Ogievskiy
2020-09-23 17:47 ` Alberto Garcia
0 siblings, 1 reply; 14+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2020-09-23 17:11 UTC (permalink / raw
To: Alberto Garcia, qemu-block
Cc: qemu-devel, fam, stefanha, mreitz, kwolf, eblake, den
23.09.2020 19:18, Alberto Garcia wrote:
> On Wed 16 Sep 2020 02:20:05 PM CEST, Vladimir Sementsov-Ogievskiy wrote:
>> - for (p = backing_bs(bs); p != base; p = backing_bs(p)) {
>> + for (p = backing_bs(bs); include_base || p != base; p = backing_bs(p)) {
>> ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map,
>> file);
>> if (ret < 0) {
>> @@ -2420,6 +2422,11 @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
>> break;
>> }
>>
>> + if (p == base) {
>> + assert(include_base);
>> + break;
>> + }
>> +
>
> Another option is something like:
>
> BlockDriverState *last_bs = include_base ? base : backing_bs(base);
hmm, in case when include_base is false, last bs is not backing_bs(base) but the parent of base.
>
> and you get a simpler 'for' loop.
>
> But why do we need include_base at all? Can't the caller just pass
> backing_bs(base) instead? I'm talking also about the existing case of
> bdrv_is_allocated_above().
>
include_base was introduced for the case when caller doesn't own backing_bs(base), and therefore shouldn't do operations that may yield (block_status can) dependent on backing_bs(base). In particular, in block stream, where link to base is not frozen.
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v6 2/5] block/io: bdrv_common_block_status_above: support include_base
2020-09-23 17:11 ` Vladimir Sementsov-Ogievskiy
@ 2020-09-23 17:47 ` Alberto Garcia
0 siblings, 0 replies; 14+ messages in thread
From: Alberto Garcia @ 2020-09-23 17:47 UTC (permalink / raw
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: fam, kwolf, qemu-devel, mreitz, stefanha, den
On Wed 23 Sep 2020 07:11:57 PM CEST, Vladimir Sementsov-Ogievskiy wrote:
>> BlockDriverState *last_bs = include_base ? base : backing_bs(base);
>
> hmm, in case when include_base is false, last bs is not
> backing_bs(base) but the parent of base.
Oops, yes, it should be the other way around %-)
>> But why do we need include_base at all? Can't the caller just pass
>> backing_bs(base) instead? I'm talking also about the existing case of
>> bdrv_is_allocated_above().
>
> include_base was introduced for the case when caller doesn't own
> backing_bs(base), and therefore shouldn't do operations that may yield
> (block_status can) dependent on backing_bs(base). In particular, in
> block stream, where link to base is not frozen.
You're right, thanks!
Berto
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v6 2/5] block/io: bdrv_common_block_status_above: support include_base
2020-09-16 12:20 ` [PATCH v6 2/5] block/io: bdrv_common_block_status_above: support include_base Vladimir Sementsov-Ogievskiy
2020-09-23 16:18 ` Alberto Garcia
@ 2020-09-23 17:49 ` Alberto Garcia
1 sibling, 0 replies; 14+ messages in thread
From: Alberto Garcia @ 2020-09-23 17:49 UTC (permalink / raw
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: fam, kwolf, vsementsov, qemu-devel, mreitz, stefanha, den
On Wed 16 Sep 2020 02:20:05 PM CEST, Vladimir Sementsov-Ogievskiy wrote:
> In order to reuse bdrv_common_block_status_above in
> bdrv_is_allocated_above, let's support include_base parameter.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Berto
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v6 1/5] block/io: fix bdrv_co_block_status_above
2020-09-16 12:20 ` [PATCH v6 1/5] block/io: fix bdrv_co_block_status_above Vladimir Sementsov-Ogievskiy
@ 2020-09-24 16:20 ` Alberto Garcia
0 siblings, 0 replies; 14+ messages in thread
From: Alberto Garcia @ 2020-09-24 16:20 UTC (permalink / raw
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: fam, kwolf, vsementsov, qemu-devel, mreitz, stefanha, den
On Wed 16 Sep 2020 02:20:04 PM CEST, Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> wrote:
> bdrv_co_block_status_above has several design problems with handling
> short backing files:
>
> 1. With want_zeros=true, it may return ret with BDRV_BLOCK_ZERO but
> without BDRV_BLOCK_ALLOCATED flag, when actually short backing file
> which produces these after-EOF zeros is inside requested backing
> sequence.
>
> 2. With want_zero=false, it may return pnum=0 prior to actual EOF,
> because of EOF of short backing file.
>
> Fix these things, making logic about short backing files clearer.
>
> With fixed bdrv_block_status_above we also have to improve is_zero in
> qcow2 code, otherwise iotest 154 will fail, because with this patch we
> stop to merge zeros of different types (produced by fully unallocated
> in the whole backing chain regions vs produced by short backing files).
>
> Note also, that this patch leaves for another day the general problem
> around block-status: misuse of BDRV_BLOCK_ALLOCATED as is-fs-allocated
> vs go-to-backing.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Berto
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v6 4/5] block/io: fix bdrv_is_allocated_above
2020-09-16 12:20 ` [PATCH v6 4/5] block/io: fix bdrv_is_allocated_above Vladimir Sementsov-Ogievskiy
@ 2020-09-24 16:21 ` Alberto Garcia
0 siblings, 0 replies; 14+ messages in thread
From: Alberto Garcia @ 2020-09-24 16:21 UTC (permalink / raw
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: fam, kwolf, vsementsov, qemu-devel, mreitz, stefanha, den
On Wed 16 Sep 2020 02:20:07 PM CEST, Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> wrote:
> bdrv_is_allocated_above wrongly handles short backing files: it reports
> after-EOF space as UNALLOCATED which is wrong, as on read the data is
> generated on the level of short backing file (if all overlays has
> unallocated area at that place).
>
> Reusing bdrv_common_block_status_above fixes the issue and unifies code
> path.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Berto
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v6 5/5] iotests: add commit top->base cases to 274
2020-09-16 12:20 ` [PATCH v6 5/5] iotests: add commit top->base cases to 274 Vladimir Sementsov-Ogievskiy
@ 2020-09-24 16:24 ` Alberto Garcia
0 siblings, 0 replies; 14+ messages in thread
From: Alberto Garcia @ 2020-09-24 16:24 UTC (permalink / raw
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: fam, kwolf, vsementsov, qemu-devel, mreitz, stefanha, den
On Wed 16 Sep 2020 02:20:08 PM CEST, Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> wrote:
> These cases are fixed by previous patches around block_status and
> is_allocated.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Berto
^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2020-09-24 16:57 UTC | newest]
Thread overview: 14+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-09-16 12:20 [PATCH v6 0/5] fix & merge block_status_above and is_allocated_above Vladimir Sementsov-Ogievskiy
2020-09-16 12:20 ` [PATCH v6 1/5] block/io: fix bdrv_co_block_status_above Vladimir Sementsov-Ogievskiy
2020-09-24 16:20 ` Alberto Garcia
2020-09-16 12:20 ` [PATCH v6 2/5] block/io: bdrv_common_block_status_above: support include_base Vladimir Sementsov-Ogievskiy
2020-09-23 16:18 ` Alberto Garcia
2020-09-23 17:11 ` Vladimir Sementsov-Ogievskiy
2020-09-23 17:47 ` Alberto Garcia
2020-09-23 17:49 ` Alberto Garcia
2020-09-16 12:20 ` [PATCH v6 3/5] block/io: bdrv_common_block_status_above: support bs == base Vladimir Sementsov-Ogievskiy
2020-09-23 16:22 ` Alberto Garcia
2020-09-16 12:20 ` [PATCH v6 4/5] block/io: fix bdrv_is_allocated_above Vladimir Sementsov-Ogievskiy
2020-09-24 16:21 ` Alberto Garcia
2020-09-16 12:20 ` [PATCH v6 5/5] iotests: add commit top->base cases to 274 Vladimir Sementsov-Ogievskiy
2020-09-24 16:24 ` Alberto Garcia
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