* [PATCH v2] block/gluster: correctly set max_pdiscard
@ 2022-05-12 10:30 Fabian Ebner
2022-05-12 15:44 ` Stefano Garzarella
0 siblings, 1 reply; 4+ messages in thread
From: Fabian Ebner @ 2022-05-12 10:30 UTC (permalink / raw)
To: qemu-devel
Cc: kwolf, hreitz, qemu-block, integration, qemu-stable, eblake, vsementsov
On 64-bit platforms, SIZE_MAX is too large for max_pdiscard, which is
int64_t, and the following assertion would be triggered:
qemu-system-x86_64: ../block/io.c:3166: bdrv_co_pdiscard: Assertion
`max_pdiscard >= bs->bl.request_alignment' failed.
Fixes: 0c8022876f ("block: use int64_t instead of int in driver discard handlers")
Cc: qemu-stable@nongnu.org
Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
---
block/gluster.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/block/gluster.c b/block/gluster.c
index 398976bc66..f711bf0bd6 100644
--- a/block/gluster.c
+++ b/block/gluster.c
@@ -891,7 +891,7 @@ out:
static void qemu_gluster_refresh_limits(BlockDriverState *bs, Error **errp)
{
bs->bl.max_transfer = GLUSTER_MAX_TRANSFER;
- bs->bl.max_pdiscard = SIZE_MAX;
+ bs->bl.max_pdiscard = MIN(SIZE_MAX, INT64_MAX);
}
static int qemu_gluster_reopen_prepare(BDRVReopenState *state,
@@ -1304,7 +1304,7 @@ static coroutine_fn int qemu_gluster_co_pdiscard(BlockDriverState *bs,
GlusterAIOCB acb;
BDRVGlusterState *s = bs->opaque;
- assert(bytes <= SIZE_MAX); /* rely on max_pdiscard */
+ assert(bytes <= MIN(SIZE_MAX, INT64_MAX)); /* rely on max_pdiscard */
acb.size = 0;
acb.ret = 0;
--
2.30.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] block/gluster: correctly set max_pdiscard
2022-05-12 10:30 [PATCH v2] block/gluster: correctly set max_pdiscard Fabian Ebner
@ 2022-05-12 15:44 ` Stefano Garzarella
2022-05-12 16:05 ` Stefano Garzarella
0 siblings, 1 reply; 4+ messages in thread
From: Stefano Garzarella @ 2022-05-12 15:44 UTC (permalink / raw)
To: Fabian Ebner
Cc: qemu-devel, kwolf, hreitz, qemu-block, integration, qemu-stable,
eblake, vsementsov
On Thu, May 12, 2022 at 12:30:48PM +0200, Fabian Ebner wrote:
>On 64-bit platforms, SIZE_MAX is too large for max_pdiscard, which is
The main problem is that SIZE_MAX for an int64_t is a negative value.
>int64_t, and the following assertion would be triggered:
>qemu-system-x86_64: ../block/io.c:3166: bdrv_co_pdiscard: Assertion
>`max_pdiscard >= bs->bl.request_alignment' failed.
>
>Fixes: 0c8022876f ("block: use int64_t instead of int in driver discard handlers")
>Cc: qemu-stable@nongnu.org
>Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
>---
> block/gluster.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
>diff --git a/block/gluster.c b/block/gluster.c
>index 398976bc66..f711bf0bd6 100644
>--- a/block/gluster.c
>+++ b/block/gluster.c
>@@ -891,7 +891,7 @@ out:
> static void qemu_gluster_refresh_limits(BlockDriverState *bs, Error **errp)
> {
> bs->bl.max_transfer = GLUSTER_MAX_TRANSFER;
>- bs->bl.max_pdiscard = SIZE_MAX;
>+ bs->bl.max_pdiscard = MIN(SIZE_MAX, INT64_MAX);
What would be the problem if we use INT64_MAX?
(I guess the intention of the original patch was to set the maximum
value in drivers that do not have a specific maximum).
Or we can set to 0, since in block/io.c we have this code:
max_pdiscard = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_pdiscard, INT64_MAX),
align);
assert(max_pdiscard >= bs->bl.request_alignment);
Where `max_pdiscard` is set to INT64_MAX (and aligned) if
bs->bl.max_pdiscard is 0.
> }
>
> static int qemu_gluster_reopen_prepare(BDRVReopenState *state,
>@@ -1304,7 +1304,7 @@ static coroutine_fn int qemu_gluster_co_pdiscard(BlockDriverState *bs,
> GlusterAIOCB acb;
> BDRVGlusterState *s = bs->opaque;
>
>- assert(bytes <= SIZE_MAX); /* rely on max_pdiscard */
>+ assert(bytes <= MIN(SIZE_MAX, INT64_MAX)); /* rely on max_pdiscard */
Can we use bs->bl.max_pdiscard directly here?
Thanks,
Stefano
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] block/gluster: correctly set max_pdiscard
2022-05-12 15:44 ` Stefano Garzarella
@ 2022-05-12 16:05 ` Stefano Garzarella
2022-05-13 6:52 ` Fabian Ebner
0 siblings, 1 reply; 4+ messages in thread
From: Stefano Garzarella @ 2022-05-12 16:05 UTC (permalink / raw)
To: Fabian Ebner
Cc: qemu-devel, kwolf, hreitz, qemu-block, integration, qemu-stable,
eblake, vsementsov
On Thu, May 12, 2022 at 05:44:13PM +0200, Stefano Garzarella wrote:
>On Thu, May 12, 2022 at 12:30:48PM +0200, Fabian Ebner wrote:
>>On 64-bit platforms, SIZE_MAX is too large for max_pdiscard, which is
>
>The main problem is that SIZE_MAX for an int64_t is a negative value.
>
>>int64_t, and the following assertion would be triggered:
>>qemu-system-x86_64: ../block/io.c:3166: bdrv_co_pdiscard: Assertion
>>`max_pdiscard >= bs->bl.request_alignment' failed.
>>
>>Fixes: 0c8022876f ("block: use int64_t instead of int in driver discard handlers")
>>Cc: qemu-stable@nongnu.org
>>Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
>>---
>>block/gluster.c | 4 ++--
>>1 file changed, 2 insertions(+), 2 deletions(-)
>>
>>diff --git a/block/gluster.c b/block/gluster.c
>>index 398976bc66..f711bf0bd6 100644
>>--- a/block/gluster.c
>>+++ b/block/gluster.c
>>@@ -891,7 +891,7 @@ out:
>>static void qemu_gluster_refresh_limits(BlockDriverState *bs, Error **errp)
>>{
>> bs->bl.max_transfer = GLUSTER_MAX_TRANSFER;
>>- bs->bl.max_pdiscard = SIZE_MAX;
>>+ bs->bl.max_pdiscard = MIN(SIZE_MAX, INT64_MAX);
>
>What would be the problem if we use INT64_MAX?
Okay, I just saw Eric's answer to v1 and I think this is right.
Please explain it in the commit message and also the initial problem
that is SIZE_MAX on a 64-bit platform is a negative number for int64_t,
so the assert fails.
Thanks,
Stefano
>(I guess the intention of the original patch was to set the maximum
>value in drivers that do not have a specific maximum).
>
>Or we can set to 0, since in block/io.c we have this code:
>
> max_pdiscard = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_pdiscard, INT64_MAX),
> align);
> assert(max_pdiscard >= bs->bl.request_alignment);
>
>Where `max_pdiscard` is set to INT64_MAX (and aligned) if
>bs->bl.max_pdiscard is 0.
>
>>}
>>
>>static int qemu_gluster_reopen_prepare(BDRVReopenState *state,
>>@@ -1304,7 +1304,7 @@ static coroutine_fn int qemu_gluster_co_pdiscard(BlockDriverState *bs,
>> GlusterAIOCB acb;
>> BDRVGlusterState *s = bs->opaque;
>>
>>- assert(bytes <= SIZE_MAX); /* rely on max_pdiscard */
>>+ assert(bytes <= MIN(SIZE_MAX, INT64_MAX)); /* rely on max_pdiscard */
>
>Can we use bs->bl.max_pdiscard directly here?
>
>Thanks,
>Stefano
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] block/gluster: correctly set max_pdiscard
2022-05-12 16:05 ` Stefano Garzarella
@ 2022-05-13 6:52 ` Fabian Ebner
0 siblings, 0 replies; 4+ messages in thread
From: Fabian Ebner @ 2022-05-13 6:52 UTC (permalink / raw)
To: Stefano Garzarella
Cc: qemu-devel, kwolf, hreitz, qemu-block, integration, qemu-stable,
eblake, vsementsov
Am 12.05.22 um 18:05 schrieb Stefano Garzarella:
> On Thu, May 12, 2022 at 05:44:13PM +0200, Stefano Garzarella wrote:
>> On Thu, May 12, 2022 at 12:30:48PM +0200, Fabian Ebner wrote:
>>> On 64-bit platforms, SIZE_MAX is too large for max_pdiscard, which is
>>
>> The main problem is that SIZE_MAX for an int64_t is a negative value.
>>
Yes, I should've stated that directly.
>>> int64_t, and the following assertion would be triggered:
>>> qemu-system-x86_64: ../block/io.c:3166: bdrv_co_pdiscard: Assertion
>>> `max_pdiscard >= bs->bl.request_alignment' failed.
>>>
>>> Fixes: 0c8022876f ("block: use int64_t instead of int in driver
>>> discard handlers")
>>> Cc: qemu-stable@nongnu.org
>>> Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
>>> ---
>>> block/gluster.c | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/block/gluster.c b/block/gluster.c
>>> index 398976bc66..f711bf0bd6 100644
>>> --- a/block/gluster.c
>>> +++ b/block/gluster.c
>>> @@ -891,7 +891,7 @@ out:
>>> static void qemu_gluster_refresh_limits(BlockDriverState *bs, Error
>>> **errp)
>>> {
>>> bs->bl.max_transfer = GLUSTER_MAX_TRANSFER;
>>> - bs->bl.max_pdiscard = SIZE_MAX;
>>> + bs->bl.max_pdiscard = MIN(SIZE_MAX, INT64_MAX);
>>
>> What would be the problem if we use INT64_MAX?
>
> Okay, I just saw Eric's answer to v1 and I think this is right.
>
Sorry for not mentioning the changes from v1.
> Please explain it in the commit message and also the initial problem
> that is SIZE_MAX on a 64-bit platform is a negative number for int64_t,
> so the assert fails.
>
I'll try and improve the commit message for v3.
> Thanks,
> Stefano
>
>> (I guess the intention of the original patch was to set the maximum
>> value in drivers that do not have a specific maximum).
>>
>> Or we can set to 0, since in block/io.c we have this code:
>>
>> max_pdiscard = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_pdiscard,
>> INT64_MAX),
>> align);
>> assert(max_pdiscard >= bs->bl.request_alignment);
>>
>> Where `max_pdiscard` is set to INT64_MAX (and aligned) if
>> bs->bl.max_pdiscard is 0.
>>
>>> }
>>>
>>> static int qemu_gluster_reopen_prepare(BDRVReopenState *state,
>>> @@ -1304,7 +1304,7 @@ static coroutine_fn int
>>> qemu_gluster_co_pdiscard(BlockDriverState *bs,
>>> GlusterAIOCB acb;
>>> BDRVGlusterState *s = bs->opaque;
>>>
>>> - assert(bytes <= SIZE_MAX); /* rely on max_pdiscard */
>>> + assert(bytes <= MIN(SIZE_MAX, INT64_MAX)); /* rely on
>>> max_pdiscard */
>>
>> Can we use bs->bl.max_pdiscard directly here?
>>
Now I'm thinking that the assert is actually for checking that the value
can be passed to glfs_discard_async(), which takes a size_t for the
argument in question. So maybe it's best to keep assert(bytes <=
SIZE_MAX) as is?
>> Thanks,
>> Stefano
>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-05-13 7:09 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-12 10:30 [PATCH v2] block/gluster: correctly set max_pdiscard Fabian Ebner
2022-05-12 15:44 ` Stefano Garzarella
2022-05-12 16:05 ` Stefano Garzarella
2022-05-13 6:52 ` Fabian Ebner
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.