* [Qemu-devel] [PATCH] block: introduce BDRV_REQUEST_MAX_SECTORS
@ 2015-02-03 12:12 Peter Lieven
2015-02-03 13:29 ` Denis V. Lunev
0 siblings, 1 reply; 6+ messages in thread
From: Peter Lieven @ 2015-02-03 12:12 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, Peter Lieven, den
we check and adjust request sizes at several places with
sometimes inconsistent checks or default values:
INT_MAX
INT_MAX >> BDRV_SECTOR_BITS
UINT_MAX >> BDRV_SECTOR_BITS
SIZE_MAX >> BDRV_SECTOR_BITS
This patches introdocues a macro for the maximal allowed sectors
per request and uses it at several places.
Signed-off-by: Peter Lieven <pl@kamp.de>
---
block.c | 19 ++++++++-----------
hw/block/virtio-blk.c | 4 ++--
include/block/block.h | 3 +++
3 files changed, 13 insertions(+), 13 deletions(-)
diff --git a/block.c b/block.c
index 8272ef9..4e58b35 100644
--- a/block.c
+++ b/block.c
@@ -2671,7 +2671,7 @@ static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num,
int nb_sectors)
{
- if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
+ if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
return -EIO;
}
@@ -2758,7 +2758,7 @@ static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf,
.iov_len = nb_sectors * BDRV_SECTOR_SIZE,
};
- if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
+ if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
return -EINVAL;
}
@@ -2826,13 +2826,10 @@ int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags)
}
for (;;) {
- nb_sectors = target_sectors - sector_num;
+ nb_sectors = MIN(target_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS);
if (nb_sectors <= 0) {
return 0;
}
- if (nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
- nb_sectors = INT_MAX / BDRV_SECTOR_SIZE;
- }
ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n);
if (ret < 0) {
error_report("error getting block status at sector %" PRId64 ": %s",
@@ -3167,7 +3164,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
BdrvRequestFlags flags)
{
- if (nb_sectors < 0 || nb_sectors > (UINT_MAX >> BDRV_SECTOR_BITS)) {
+ if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
return -EINVAL;
}
@@ -3202,8 +3199,8 @@ static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
struct iovec iov = {0};
int ret = 0;
- int max_write_zeroes = bs->bl.max_write_zeroes ?
- bs->bl.max_write_zeroes : INT_MAX;
+ int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_write_zeroes,
+ BDRV_REQUEST_MAX_SECTORS);
while (nb_sectors > 0 && !ret) {
int num = nb_sectors;
@@ -3458,7 +3455,7 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
BdrvRequestFlags flags)
{
- if (nb_sectors < 0 || nb_sectors > (INT_MAX >> BDRV_SECTOR_BITS)) {
+ if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
return -EINVAL;
}
@@ -5120,7 +5117,7 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
return 0;
}
- max_discard = bs->bl.max_discard ? bs->bl.max_discard : INT_MAX;
+ max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS);
while (nb_sectors > 0) {
int ret;
int num = nb_sectors;
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 8c51a29..1a8a176 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -381,7 +381,7 @@ void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
}
max_xfer_len = blk_get_max_transfer_length(mrb->reqs[0]->dev->blk);
- max_xfer_len = MIN_NON_ZERO(max_xfer_len, INT_MAX);
+ max_xfer_len = MIN_NON_ZERO(max_xfer_len, BDRV_REQUEST_MAX_SECTORS);
qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs),
&multireq_compare);
@@ -447,7 +447,7 @@ static bool virtio_blk_sect_range_ok(VirtIOBlock *dev,
uint64_t nb_sectors = size >> BDRV_SECTOR_BITS;
uint64_t total_sectors;
- if (nb_sectors > INT_MAX) {
+ if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
return false;
}
if (sector & dev->sector_mask) {
diff --git a/include/block/block.h b/include/block/block.h
index 3082d2b..25a6d62 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -83,6 +83,9 @@ typedef enum {
#define BDRV_SECTOR_SIZE (1ULL << BDRV_SECTOR_BITS)
#define BDRV_SECTOR_MASK ~(BDRV_SECTOR_SIZE - 1)
+#define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
+ INT_MAX >> BDRV_SECTOR_BITS)
+
/*
* Allocation status flags
* BDRV_BLOCK_DATA: data is read from bs->file or another file
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH] block: introduce BDRV_REQUEST_MAX_SECTORS
2015-02-03 12:12 [Qemu-devel] [PATCH] block: introduce BDRV_REQUEST_MAX_SECTORS Peter Lieven
@ 2015-02-03 13:29 ` Denis V. Lunev
2015-02-03 14:30 ` Peter Lieven
0 siblings, 1 reply; 6+ messages in thread
From: Denis V. Lunev @ 2015-02-03 13:29 UTC (permalink / raw)
To: Peter Lieven, qemu-devel; +Cc: kwolf
On 03/02/15 15:12, Peter Lieven wrote:
> we check and adjust request sizes at several places with
> sometimes inconsistent checks or default values:
> INT_MAX
> INT_MAX >> BDRV_SECTOR_BITS
> UINT_MAX >> BDRV_SECTOR_BITS
> SIZE_MAX >> BDRV_SECTOR_BITS
>
> This patches introdocues a macro for the maximal allowed sectors
> per request and uses it at several places.
>
> Signed-off-by: Peter Lieven <pl@kamp.de>
> ---
> block.c | 19 ++++++++-----------
> hw/block/virtio-blk.c | 4 ++--
> include/block/block.h | 3 +++
> 3 files changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/block.c b/block.c
> index 8272ef9..4e58b35 100644
> --- a/block.c
> +++ b/block.c
> @@ -2671,7 +2671,7 @@ static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
> static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num,
> int nb_sectors)
> {
> - if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
> return -EIO;
> }
>
> @@ -2758,7 +2758,7 @@ static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf,
> .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
> };
>
> - if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
> return -EINVAL;
> }
>
> @@ -2826,13 +2826,10 @@ int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags)
> }
>
> for (;;) {
> - nb_sectors = target_sectors - sector_num;
> + nb_sectors = MIN(target_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS);
> if (nb_sectors <= 0) {
> return 0;
> }
> - if (nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
> - nb_sectors = INT_MAX / BDRV_SECTOR_SIZE;
> - }
> ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n);
> if (ret < 0) {
> error_report("error getting block status at sector %" PRId64 ": %s",
> @@ -3167,7 +3164,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
> BdrvRequestFlags flags)
> {
> - if (nb_sectors < 0 || nb_sectors > (UINT_MAX >> BDRV_SECTOR_BITS)) {
> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
> return -EINVAL;
> }
>
> @@ -3202,8 +3199,8 @@ static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
> struct iovec iov = {0};
> int ret = 0;
>
> - int max_write_zeroes = bs->bl.max_write_zeroes ?
> - bs->bl.max_write_zeroes : INT_MAX;
> + int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_write_zeroes,
> + BDRV_REQUEST_MAX_SECTORS);
>
> while (nb_sectors > 0 && !ret) {
> int num = nb_sectors;
> @@ -3458,7 +3455,7 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
> BdrvRequestFlags flags)
> {
> - if (nb_sectors < 0 || nb_sectors > (INT_MAX >> BDRV_SECTOR_BITS)) {
> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
> return -EINVAL;
> }
>
> @@ -5120,7 +5117,7 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
> return 0;
> }
>
> - max_discard = bs->bl.max_discard ? bs->bl.max_discard : INT_MAX;
> + max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS);
> while (nb_sectors > 0) {
> int ret;
> int num = nb_sectors;
> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> index 8c51a29..1a8a176 100644
> --- a/hw/block/virtio-blk.c
> +++ b/hw/block/virtio-blk.c
> @@ -381,7 +381,7 @@ void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
> }
>
> max_xfer_len = blk_get_max_transfer_length(mrb->reqs[0]->dev->blk);
> - max_xfer_len = MIN_NON_ZERO(max_xfer_len, INT_MAX);
> + max_xfer_len = MIN_NON_ZERO(max_xfer_len, BDRV_REQUEST_MAX_SECTORS);
>
> qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs),
> &multireq_compare);
> @@ -447,7 +447,7 @@ static bool virtio_blk_sect_range_ok(VirtIOBlock *dev,
> uint64_t nb_sectors = size >> BDRV_SECTOR_BITS;
> uint64_t total_sectors;
>
> - if (nb_sectors > INT_MAX) {
> + if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
> return false;
> }
> if (sector & dev->sector_mask) {
> diff --git a/include/block/block.h b/include/block/block.h
> index 3082d2b..25a6d62 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -83,6 +83,9 @@ typedef enum {
> #define BDRV_SECTOR_SIZE (1ULL << BDRV_SECTOR_BITS)
> #define BDRV_SECTOR_MASK ~(BDRV_SECTOR_SIZE - 1)
>
> +#define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
> + INT_MAX >> BDRV_SECTOR_BITS)
> +
> /*
> * Allocation status flags
> * BDRV_BLOCK_DATA: data is read from bs->file or another file
Reviewed-by: Denis V. Lunev <den@openvz.org>
On the other hand the limitation to INT_MAX for a request size
(in bytes) is here.
bdrv_check_byte_request
if (size > INT_MAX) {
return -EIO;
}
which means that all my patches from series
[PATCH v3 0/2] fix max_discard for NBD/gluster block drivers
becomes unnecessary but this was not that obvious before this
clarification :)
Den
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH] block: introduce BDRV_REQUEST_MAX_SECTORS
2015-02-03 13:29 ` Denis V. Lunev
@ 2015-02-03 14:30 ` Peter Lieven
2015-02-03 15:33 ` Denis V. Lunev
0 siblings, 1 reply; 6+ messages in thread
From: Peter Lieven @ 2015-02-03 14:30 UTC (permalink / raw)
To: Denis V. Lunev, qemu-devel; +Cc: kwolf
Am 03.02.2015 um 14:29 schrieb Denis V. Lunev:
> On 03/02/15 15:12, Peter Lieven wrote:
>> we check and adjust request sizes at several places with
>> sometimes inconsistent checks or default values:
>> INT_MAX
>> INT_MAX >> BDRV_SECTOR_BITS
>> UINT_MAX >> BDRV_SECTOR_BITS
>> SIZE_MAX >> BDRV_SECTOR_BITS
>>
>> This patches introdocues a macro for the maximal allowed sectors
>> per request and uses it at several places.
>>
>> Signed-off-by: Peter Lieven <pl@kamp.de>
>> ---
>> block.c | 19 ++++++++-----------
>> hw/block/virtio-blk.c | 4 ++--
>> include/block/block.h | 3 +++
>> 3 files changed, 13 insertions(+), 13 deletions(-)
>>
>> diff --git a/block.c b/block.c
>> index 8272ef9..4e58b35 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -2671,7 +2671,7 @@ static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
>> static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num,
>> int nb_sectors)
>> {
>> - if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>> return -EIO;
>> }
>> @@ -2758,7 +2758,7 @@ static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf,
>> .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
>> };
>> - if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>> return -EINVAL;
>> }
>> @@ -2826,13 +2826,10 @@ int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags)
>> }
>> for (;;) {
>> - nb_sectors = target_sectors - sector_num;
>> + nb_sectors = MIN(target_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS);
>> if (nb_sectors <= 0) {
>> return 0;
>> }
>> - if (nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
>> - nb_sectors = INT_MAX / BDRV_SECTOR_SIZE;
>> - }
>> ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n);
>> if (ret < 0) {
>> error_report("error getting block status at sector %" PRId64 ": %s",
>> @@ -3167,7 +3164,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
>> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
>> BdrvRequestFlags flags)
>> {
>> - if (nb_sectors < 0 || nb_sectors > (UINT_MAX >> BDRV_SECTOR_BITS)) {
>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>> return -EINVAL;
>> }
>> @@ -3202,8 +3199,8 @@ static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
>> struct iovec iov = {0};
>> int ret = 0;
>> - int max_write_zeroes = bs->bl.max_write_zeroes ?
>> - bs->bl.max_write_zeroes : INT_MAX;
>> + int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_write_zeroes,
>> + BDRV_REQUEST_MAX_SECTORS);
>> while (nb_sectors > 0 && !ret) {
>> int num = nb_sectors;
>> @@ -3458,7 +3455,7 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
>> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
>> BdrvRequestFlags flags)
>> {
>> - if (nb_sectors < 0 || nb_sectors > (INT_MAX >> BDRV_SECTOR_BITS)) {
>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>> return -EINVAL;
>> }
>> @@ -5120,7 +5117,7 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
>> return 0;
>> }
>> - max_discard = bs->bl.max_discard ? bs->bl.max_discard : INT_MAX;
>> + max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS);
>> while (nb_sectors > 0) {
>> int ret;
>> int num = nb_sectors;
>> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
>> index 8c51a29..1a8a176 100644
>> --- a/hw/block/virtio-blk.c
>> +++ b/hw/block/virtio-blk.c
>> @@ -381,7 +381,7 @@ void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
>> }
>> max_xfer_len = blk_get_max_transfer_length(mrb->reqs[0]->dev->blk);
>> - max_xfer_len = MIN_NON_ZERO(max_xfer_len, INT_MAX);
>> + max_xfer_len = MIN_NON_ZERO(max_xfer_len, BDRV_REQUEST_MAX_SECTORS);
>> qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs),
>> &multireq_compare);
>> @@ -447,7 +447,7 @@ static bool virtio_blk_sect_range_ok(VirtIOBlock *dev,
>> uint64_t nb_sectors = size >> BDRV_SECTOR_BITS;
>> uint64_t total_sectors;
>> - if (nb_sectors > INT_MAX) {
>> + if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>> return false;
>> }
>> if (sector & dev->sector_mask) {
>> diff --git a/include/block/block.h b/include/block/block.h
>> index 3082d2b..25a6d62 100644
>> --- a/include/block/block.h
>> +++ b/include/block/block.h
>> @@ -83,6 +83,9 @@ typedef enum {
>> #define BDRV_SECTOR_SIZE (1ULL << BDRV_SECTOR_BITS)
>> #define BDRV_SECTOR_MASK ~(BDRV_SECTOR_SIZE - 1)
>> +#define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
>> + INT_MAX >> BDRV_SECTOR_BITS)
>> +
>> /*
>> * Allocation status flags
>> * BDRV_BLOCK_DATA: data is read from bs->file or another file
> Reviewed-by: Denis V. Lunev <den@openvz.org>
>
> On the other hand the limitation to INT_MAX for a request size
> (in bytes) is here.
>
> bdrv_check_byte_request
> if (size > INT_MAX) {
> return -EIO;
> }
>
> which means that all my patches from series
> [PATCH v3 0/2] fix max_discard for NBD/gluster block drivers
> becomes unnecessary but this was not that obvious before this
> clarification :)
No, not completely. If we run into the check above the request fails.
If you set max_write_zeroes the request is appropiately trimmed.
So if the driver allows less than BDRV_REQUEST_MAX_SECTORS sectors
you still have to set it in the BlockLimits.
Peter
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH] block: introduce BDRV_REQUEST_MAX_SECTORS
2015-02-03 14:30 ` Peter Lieven
@ 2015-02-03 15:33 ` Denis V. Lunev
2015-02-06 8:49 ` Peter Lieven
0 siblings, 1 reply; 6+ messages in thread
From: Denis V. Lunev @ 2015-02-03 15:33 UTC (permalink / raw)
To: Peter Lieven, qemu-devel; +Cc: kwolf
On 03/02/15 17:30, Peter Lieven wrote:
> Am 03.02.2015 um 14:29 schrieb Denis V. Lunev:
>> On 03/02/15 15:12, Peter Lieven wrote:
>>> we check and adjust request sizes at several places with
>>> sometimes inconsistent checks or default values:
>>> INT_MAX
>>> INT_MAX >> BDRV_SECTOR_BITS
>>> UINT_MAX >> BDRV_SECTOR_BITS
>>> SIZE_MAX >> BDRV_SECTOR_BITS
>>>
>>> This patches introdocues a macro for the maximal allowed sectors
>>> per request and uses it at several places.
>>>
>>> Signed-off-by: Peter Lieven <pl@kamp.de>
>>> ---
>>> block.c | 19 ++++++++-----------
>>> hw/block/virtio-blk.c | 4 ++--
>>> include/block/block.h | 3 +++
>>> 3 files changed, 13 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/block.c b/block.c
>>> index 8272ef9..4e58b35 100644
>>> --- a/block.c
>>> +++ b/block.c
>>> @@ -2671,7 +2671,7 @@ static int
>>> bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
>>> static int bdrv_check_request(BlockDriverState *bs, int64_t
>>> sector_num,
>>> int nb_sectors)
>>> {
>>> - if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>> return -EIO;
>>> }
>>> @@ -2758,7 +2758,7 @@ static int bdrv_rw_co(BlockDriverState *bs,
>>> int64_t sector_num, uint8_t *buf,
>>> .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
>>> };
>>> - if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>> return -EINVAL;
>>> }
>>> @@ -2826,13 +2826,10 @@ int bdrv_make_zero(BlockDriverState *bs,
>>> BdrvRequestFlags flags)
>>> }
>>> for (;;) {
>>> - nb_sectors = target_sectors - sector_num;
>>> + nb_sectors = MIN(target_sectors - sector_num,
>>> BDRV_REQUEST_MAX_SECTORS);
>>> if (nb_sectors <= 0) {
>>> return 0;
>>> }
>>> - if (nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
>>> - nb_sectors = INT_MAX / BDRV_SECTOR_SIZE;
>>> - }
>>> ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n);
>>> if (ret < 0) {
>>> error_report("error getting block status at sector %"
>>> PRId64 ": %s",
>>> @@ -3167,7 +3164,7 @@ static int coroutine_fn
>>> bdrv_co_do_readv(BlockDriverState *bs,
>>> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
>>> BdrvRequestFlags flags)
>>> {
>>> - if (nb_sectors < 0 || nb_sectors > (UINT_MAX >>
>>> BDRV_SECTOR_BITS)) {
>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>> return -EINVAL;
>>> }
>>> @@ -3202,8 +3199,8 @@ static int coroutine_fn
>>> bdrv_co_do_write_zeroes(BlockDriverState *bs,
>>> struct iovec iov = {0};
>>> int ret = 0;
>>> - int max_write_zeroes = bs->bl.max_write_zeroes ?
>>> - bs->bl.max_write_zeroes : INT_MAX;
>>> + int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_write_zeroes,
>>> + BDRV_REQUEST_MAX_SECTORS);
>>> while (nb_sectors > 0 && !ret) {
>>> int num = nb_sectors;
>>> @@ -3458,7 +3455,7 @@ static int coroutine_fn
>>> bdrv_co_do_writev(BlockDriverState *bs,
>>> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
>>> BdrvRequestFlags flags)
>>> {
>>> - if (nb_sectors < 0 || nb_sectors > (INT_MAX >>
>>> BDRV_SECTOR_BITS)) {
>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>> return -EINVAL;
>>> }
>>> @@ -5120,7 +5117,7 @@ int coroutine_fn
>>> bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
>>> return 0;
>>> }
>>> - max_discard = bs->bl.max_discard ? bs->bl.max_discard : INT_MAX;
>>> + max_discard = MIN_NON_ZERO(bs->bl.max_discard,
>>> BDRV_REQUEST_MAX_SECTORS);
>>> while (nb_sectors > 0) {
>>> int ret;
>>> int num = nb_sectors;
>>> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
>>> index 8c51a29..1a8a176 100644
>>> --- a/hw/block/virtio-blk.c
>>> +++ b/hw/block/virtio-blk.c
>>> @@ -381,7 +381,7 @@ void virtio_blk_submit_multireq(BlockBackend
>>> *blk, MultiReqBuffer *mrb)
>>> }
>>> max_xfer_len =
>>> blk_get_max_transfer_length(mrb->reqs[0]->dev->blk);
>>> - max_xfer_len = MIN_NON_ZERO(max_xfer_len, INT_MAX);
>>> + max_xfer_len = MIN_NON_ZERO(max_xfer_len,
>>> BDRV_REQUEST_MAX_SECTORS);
>>> qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs),
>>> &multireq_compare);
>>> @@ -447,7 +447,7 @@ static bool virtio_blk_sect_range_ok(VirtIOBlock
>>> *dev,
>>> uint64_t nb_sectors = size >> BDRV_SECTOR_BITS;
>>> uint64_t total_sectors;
>>> - if (nb_sectors > INT_MAX) {
>>> + if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>> return false;
>>> }
>>> if (sector & dev->sector_mask) {
>>> diff --git a/include/block/block.h b/include/block/block.h
>>> index 3082d2b..25a6d62 100644
>>> --- a/include/block/block.h
>>> +++ b/include/block/block.h
>>> @@ -83,6 +83,9 @@ typedef enum {
>>> #define BDRV_SECTOR_SIZE (1ULL << BDRV_SECTOR_BITS)
>>> #define BDRV_SECTOR_MASK ~(BDRV_SECTOR_SIZE - 1)
>>> +#define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
>>> + INT_MAX >> BDRV_SECTOR_BITS)
>>> +
>>> /*
>>> * Allocation status flags
>>> * BDRV_BLOCK_DATA: data is read from bs->file or another file
>> Reviewed-by: Denis V. Lunev <den@openvz.org>
>>
>> On the other hand the limitation to INT_MAX for a request size
>> (in bytes) is here.
>>
>> bdrv_check_byte_request
>> if (size > INT_MAX) {
>> return -EIO;
>> }
>>
>> which means that all my patches from series
>> [PATCH v3 0/2] fix max_discard for NBD/gluster block drivers
>> becomes unnecessary but this was not that obvious before this
>> clarification :)
>
> No, not completely. If we run into the check above the request fails.
> If you set max_write_zeroes the request is appropiately trimmed.
> So if the driver allows less than BDRV_REQUEST_MAX_SECTORS sectors
> you still have to set it in the BlockLimits.
>
> Peter
>
your point will be correct after the following patch applied
diff --git a/block.c b/block.c
index 4e58b35..49e0073 100644
--- a/block.c
+++ b/block.c
@@ -2647,7 +2647,7 @@ static int
bdrv_check_byte_request(BlockDriverState *bs, i
{
int64_t len;
- if (size > INT_MAX) {
+ if (size > BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS) {
return -EIO;
}
without we will fail at entry point inside bdrv_check_byte_request().
My patch applies the limit of UINT32_MAX over the value which
is not greater than INT_MAX in the current codebase.
bdrv_check_byte_request() is performed at the very-very beginning
of the processing, f.e
bdrv_co_discard
bdrv_check_request
bdrv_check_byte_request <-- (INT_MAX limit applied)
max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS);
Den
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH] block: introduce BDRV_REQUEST_MAX_SECTORS
2015-02-03 15:33 ` Denis V. Lunev
@ 2015-02-06 8:49 ` Peter Lieven
2015-02-06 9:09 ` Denis V. Lunev
0 siblings, 1 reply; 6+ messages in thread
From: Peter Lieven @ 2015-02-06 8:49 UTC (permalink / raw)
To: Denis V. Lunev, qemu-devel; +Cc: kwolf
Am 03.02.2015 um 16:33 schrieb Denis V. Lunev:
> On 03/02/15 17:30, Peter Lieven wrote:
>> Am 03.02.2015 um 14:29 schrieb Denis V. Lunev:
>>> On 03/02/15 15:12, Peter Lieven wrote:
>>>> we check and adjust request sizes at several places with
>>>> sometimes inconsistent checks or default values:
>>>> INT_MAX
>>>> INT_MAX >> BDRV_SECTOR_BITS
>>>> UINT_MAX >> BDRV_SECTOR_BITS
>>>> SIZE_MAX >> BDRV_SECTOR_BITS
>>>>
>>>> This patches introdocues a macro for the maximal allowed sectors
>>>> per request and uses it at several places.
>>>>
>>>> Signed-off-by: Peter Lieven <pl@kamp.de>
>>>> ---
>>>> block.c | 19 ++++++++-----------
>>>> hw/block/virtio-blk.c | 4 ++--
>>>> include/block/block.h | 3 +++
>>>> 3 files changed, 13 insertions(+), 13 deletions(-)
>>>>
>>>> diff --git a/block.c b/block.c
>>>> index 8272ef9..4e58b35 100644
>>>> --- a/block.c
>>>> +++ b/block.c
>>>> @@ -2671,7 +2671,7 @@ static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
>>>> static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num,
>>>> int nb_sectors)
>>>> {
>>>> - if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
>>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>>> return -EIO;
>>>> }
>>>> @@ -2758,7 +2758,7 @@ static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf,
>>>> .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
>>>> };
>>>> - if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
>>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>>> return -EINVAL;
>>>> }
>>>> @@ -2826,13 +2826,10 @@ int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags)
>>>> }
>>>> for (;;) {
>>>> - nb_sectors = target_sectors - sector_num;
>>>> + nb_sectors = MIN(target_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS);
>>>> if (nb_sectors <= 0) {
>>>> return 0;
>>>> }
>>>> - if (nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
>>>> - nb_sectors = INT_MAX / BDRV_SECTOR_SIZE;
>>>> - }
>>>> ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n);
>>>> if (ret < 0) {
>>>> error_report("error getting block status at sector %" PRId64 ": %s",
>>>> @@ -3167,7 +3164,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
>>>> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
>>>> BdrvRequestFlags flags)
>>>> {
>>>> - if (nb_sectors < 0 || nb_sectors > (UINT_MAX >> BDRV_SECTOR_BITS)) {
>>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>>> return -EINVAL;
>>>> }
>>>> @@ -3202,8 +3199,8 @@ static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
>>>> struct iovec iov = {0};
>>>> int ret = 0;
>>>> - int max_write_zeroes = bs->bl.max_write_zeroes ?
>>>> - bs->bl.max_write_zeroes : INT_MAX;
>>>> + int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_write_zeroes,
>>>> + BDRV_REQUEST_MAX_SECTORS);
>>>> while (nb_sectors > 0 && !ret) {
>>>> int num = nb_sectors;
>>>> @@ -3458,7 +3455,7 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
>>>> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
>>>> BdrvRequestFlags flags)
>>>> {
>>>> - if (nb_sectors < 0 || nb_sectors > (INT_MAX >> BDRV_SECTOR_BITS)) {
>>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>>> return -EINVAL;
>>>> }
>>>> @@ -5120,7 +5117,7 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
>>>> return 0;
>>>> }
>>>> - max_discard = bs->bl.max_discard ? bs->bl.max_discard : INT_MAX;
>>>> + max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS);
>>>> while (nb_sectors > 0) {
>>>> int ret;
>>>> int num = nb_sectors;
>>>> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
>>>> index 8c51a29..1a8a176 100644
>>>> --- a/hw/block/virtio-blk.c
>>>> +++ b/hw/block/virtio-blk.c
>>>> @@ -381,7 +381,7 @@ void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
>>>> }
>>>> max_xfer_len = blk_get_max_transfer_length(mrb->reqs[0]->dev->blk);
>>>> - max_xfer_len = MIN_NON_ZERO(max_xfer_len, INT_MAX);
>>>> + max_xfer_len = MIN_NON_ZERO(max_xfer_len, BDRV_REQUEST_MAX_SECTORS);
>>>> qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs),
>>>> &multireq_compare);
>>>> @@ -447,7 +447,7 @@ static bool virtio_blk_sect_range_ok(VirtIOBlock *dev,
>>>> uint64_t nb_sectors = size >> BDRV_SECTOR_BITS;
>>>> uint64_t total_sectors;
>>>> - if (nb_sectors > INT_MAX) {
>>>> + if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>>> return false;
>>>> }
>>>> if (sector & dev->sector_mask) {
>>>> diff --git a/include/block/block.h b/include/block/block.h
>>>> index 3082d2b..25a6d62 100644
>>>> --- a/include/block/block.h
>>>> +++ b/include/block/block.h
>>>> @@ -83,6 +83,9 @@ typedef enum {
>>>> #define BDRV_SECTOR_SIZE (1ULL << BDRV_SECTOR_BITS)
>>>> #define BDRV_SECTOR_MASK ~(BDRV_SECTOR_SIZE - 1)
>>>> +#define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
>>>> + INT_MAX >> BDRV_SECTOR_BITS)
>>>> +
>>>> /*
>>>> * Allocation status flags
>>>> * BDRV_BLOCK_DATA: data is read from bs->file or another file
>>> Reviewed-by: Denis V. Lunev <den@openvz.org>
>>>
>>> On the other hand the limitation to INT_MAX for a request size
>>> (in bytes) is here.
>>>
>>> bdrv_check_byte_request
>>> if (size > INT_MAX) {
>>> return -EIO;
>>> }
>>>
>>> which means that all my patches from series
>>> [PATCH v3 0/2] fix max_discard for NBD/gluster block drivers
>>> becomes unnecessary but this was not that obvious before this
>>> clarification :)
>>
>> No, not completely. If we run into the check above the request fails.
>> If you set max_write_zeroes the request is appropiately trimmed.
>> So if the driver allows less than BDRV_REQUEST_MAX_SECTORS sectors
>> you still have to set it in the BlockLimits.
>>
>> Peter
>>
> your point will be correct after the following patch applied
>
> diff --git a/block.c b/block.c
> index 4e58b35..49e0073 100644
> --- a/block.c
> +++ b/block.c
> @@ -2647,7 +2647,7 @@ static int bdrv_check_byte_request(BlockDriverState *bs, i
> {
> int64_t len;
>
> - if (size > INT_MAX) {
> + if (size > BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS) {
> return -EIO;
> }
You are right, this will still fail if SIZE_MAX < INT_MAX. I would send a v2 of my
patch and add the above. Then Kevin can remove your 2 patches, right?
Peter
>
> without we will fail at entry point inside bdrv_check_byte_request().
> My patch applies the limit of UINT32_MAX over the value which
> is not greater than INT_MAX in the current codebase.
> bdrv_check_byte_request() is performed at the very-very beginning
> of the processing, f.e
>
> bdrv_co_discard
> bdrv_check_request
> bdrv_check_byte_request <-- (INT_MAX limit applied)
> max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS);
>
> Den
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH] block: introduce BDRV_REQUEST_MAX_SECTORS
2015-02-06 8:49 ` Peter Lieven
@ 2015-02-06 9:09 ` Denis V. Lunev
0 siblings, 0 replies; 6+ messages in thread
From: Denis V. Lunev @ 2015-02-06 9:09 UTC (permalink / raw)
To: Peter Lieven, qemu-devel; +Cc: kwolf
On 06/02/15 11:49, Peter Lieven wrote:
> Am 03.02.2015 um 16:33 schrieb Denis V. Lunev:
>> On 03/02/15 17:30, Peter Lieven wrote:
>>> Am 03.02.2015 um 14:29 schrieb Denis V. Lunev:
>>>> On 03/02/15 15:12, Peter Lieven wrote:
>>>>> we check and adjust request sizes at several places with
>>>>> sometimes inconsistent checks or default values:
>>>>> INT_MAX
>>>>> INT_MAX >> BDRV_SECTOR_BITS
>>>>> UINT_MAX >> BDRV_SECTOR_BITS
>>>>> SIZE_MAX >> BDRV_SECTOR_BITS
>>>>>
>>>>> This patches introdocues a macro for the maximal allowed sectors
>>>>> per request and uses it at several places.
>>>>>
>>>>> Signed-off-by: Peter Lieven <pl@kamp.de>
>>>>> ---
>>>>> block.c | 19 ++++++++-----------
>>>>> hw/block/virtio-blk.c | 4 ++--
>>>>> include/block/block.h | 3 +++
>>>>> 3 files changed, 13 insertions(+), 13 deletions(-)
>>>>>
>>>>> diff --git a/block.c b/block.c
>>>>> index 8272ef9..4e58b35 100644
>>>>> --- a/block.c
>>>>> +++ b/block.c
>>>>> @@ -2671,7 +2671,7 @@ static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
>>>>> static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num,
>>>>> int nb_sectors)
>>>>> {
>>>>> - if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
>>>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>>>> return -EIO;
>>>>> }
>>>>> @@ -2758,7 +2758,7 @@ static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf,
>>>>> .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
>>>>> };
>>>>> - if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
>>>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>>>> return -EINVAL;
>>>>> }
>>>>> @@ -2826,13 +2826,10 @@ int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags)
>>>>> }
>>>>> for (;;) {
>>>>> - nb_sectors = target_sectors - sector_num;
>>>>> + nb_sectors = MIN(target_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS);
>>>>> if (nb_sectors <= 0) {
>>>>> return 0;
>>>>> }
>>>>> - if (nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
>>>>> - nb_sectors = INT_MAX / BDRV_SECTOR_SIZE;
>>>>> - }
>>>>> ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n);
>>>>> if (ret < 0) {
>>>>> error_report("error getting block status at sector %" PRId64 ": %s",
>>>>> @@ -3167,7 +3164,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
>>>>> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
>>>>> BdrvRequestFlags flags)
>>>>> {
>>>>> - if (nb_sectors < 0 || nb_sectors > (UINT_MAX >> BDRV_SECTOR_BITS)) {
>>>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>>>> return -EINVAL;
>>>>> }
>>>>> @@ -3202,8 +3199,8 @@ static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
>>>>> struct iovec iov = {0};
>>>>> int ret = 0;
>>>>> - int max_write_zeroes = bs->bl.max_write_zeroes ?
>>>>> - bs->bl.max_write_zeroes : INT_MAX;
>>>>> + int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_write_zeroes,
>>>>> + BDRV_REQUEST_MAX_SECTORS);
>>>>> while (nb_sectors > 0 && !ret) {
>>>>> int num = nb_sectors;
>>>>> @@ -3458,7 +3455,7 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
>>>>> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
>>>>> BdrvRequestFlags flags)
>>>>> {
>>>>> - if (nb_sectors < 0 || nb_sectors > (INT_MAX >> BDRV_SECTOR_BITS)) {
>>>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>>>> return -EINVAL;
>>>>> }
>>>>> @@ -5120,7 +5117,7 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
>>>>> return 0;
>>>>> }
>>>>> - max_discard = bs->bl.max_discard ? bs->bl.max_discard : INT_MAX;
>>>>> + max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS);
>>>>> while (nb_sectors > 0) {
>>>>> int ret;
>>>>> int num = nb_sectors;
>>>>> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
>>>>> index 8c51a29..1a8a176 100644
>>>>> --- a/hw/block/virtio-blk.c
>>>>> +++ b/hw/block/virtio-blk.c
>>>>> @@ -381,7 +381,7 @@ void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
>>>>> }
>>>>> max_xfer_len = blk_get_max_transfer_length(mrb->reqs[0]->dev->blk);
>>>>> - max_xfer_len = MIN_NON_ZERO(max_xfer_len, INT_MAX);
>>>>> + max_xfer_len = MIN_NON_ZERO(max_xfer_len, BDRV_REQUEST_MAX_SECTORS);
>>>>> qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs),
>>>>> &multireq_compare);
>>>>> @@ -447,7 +447,7 @@ static bool virtio_blk_sect_range_ok(VirtIOBlock *dev,
>>>>> uint64_t nb_sectors = size >> BDRV_SECTOR_BITS;
>>>>> uint64_t total_sectors;
>>>>> - if (nb_sectors > INT_MAX) {
>>>>> + if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
>>>>> return false;
>>>>> }
>>>>> if (sector & dev->sector_mask) {
>>>>> diff --git a/include/block/block.h b/include/block/block.h
>>>>> index 3082d2b..25a6d62 100644
>>>>> --- a/include/block/block.h
>>>>> +++ b/include/block/block.h
>>>>> @@ -83,6 +83,9 @@ typedef enum {
>>>>> #define BDRV_SECTOR_SIZE (1ULL << BDRV_SECTOR_BITS)
>>>>> #define BDRV_SECTOR_MASK ~(BDRV_SECTOR_SIZE - 1)
>>>>> +#define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \
>>>>> + INT_MAX >> BDRV_SECTOR_BITS)
>>>>> +
>>>>> /*
>>>>> * Allocation status flags
>>>>> * BDRV_BLOCK_DATA: data is read from bs->file or another file
>>>> Reviewed-by: Denis V. Lunev <den@openvz.org>
>>>>
>>>> On the other hand the limitation to INT_MAX for a request size
>>>> (in bytes) is here.
>>>>
>>>> bdrv_check_byte_request
>>>> if (size > INT_MAX) {
>>>> return -EIO;
>>>> }
>>>>
>>>> which means that all my patches from series
>>>> [PATCH v3 0/2] fix max_discard for NBD/gluster block drivers
>>>> becomes unnecessary but this was not that obvious before this
>>>> clarification :)
>>> No, not completely. If we run into the check above the request fails.
>>> If you set max_write_zeroes the request is appropiately trimmed.
>>> So if the driver allows less than BDRV_REQUEST_MAX_SECTORS sectors
>>> you still have to set it in the BlockLimits.
>>>
>>> Peter
>>>
>> your point will be correct after the following patch applied
>>
>> diff --git a/block.c b/block.c
>> index 4e58b35..49e0073 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -2647,7 +2647,7 @@ static int bdrv_check_byte_request(BlockDriverState *bs, i
>> {
>> int64_t len;
>>
>> - if (size > INT_MAX) {
>> + if (size > BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS) {
>> return -EIO;
>> }
> You are right, this will still fail if SIZE_MAX < INT_MAX. I would send a v2 of my
> patch and add the above. Then Kevin can remove your 2 patches, right?
>
> Peter
>
that's cool. Though in this case NBD patch will be necessary. Gluster
code is correct.
I'll re-spin it as some modification is necessary.
>> without we will fail at entry point inside bdrv_check_byte_request().
>> My patch applies the limit of UINT32_MAX over the value which
>> is not greater than INT_MAX in the current codebase.
>> bdrv_check_byte_request() is performed at the very-very beginning
>> of the processing, f.e
>>
>> bdrv_co_discard
>> bdrv_check_request
>> bdrv_check_byte_request <-- (INT_MAX limit applied)
>> max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS);
>>
>> Den
^ permalink raw reply [flat|nested] 6+ messages in thread
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2015-02-03 12:12 [Qemu-devel] [PATCH] block: introduce BDRV_REQUEST_MAX_SECTORS Peter Lieven
2015-02-03 13:29 ` Denis V. Lunev
2015-02-03 14:30 ` Peter Lieven
2015-02-03 15:33 ` Denis V. Lunev
2015-02-06 8:49 ` Peter Lieven
2015-02-06 9:09 ` Denis V. Lunev
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