| Message ID | 20240806133058.268058-3-w@uter.be (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,1/3] nbd: implement the WRITE_ZEROES command | expand |
On Tue, Aug 06, 2024 at 03:30:56PM +0200, Wouter Verhelst wrote: > The version of the NBD protocol implemented by the kernel driver > currently has a 32 bit field for length values. As the NBD protocol uses > bytes as a unit of length, length values larger than 2^32 bytes cannot > be expressed. > > Update the max_hw_discard_sectors field to match that. > > Signed-off-by: Wouter Verhelst <w@uter.be> > Fixes: 268283244c0f018dec8bf4a9c69ce50684561f46 > --- > drivers/block/nbd.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c > index 20e9f9fdeaae..1457f0c8a4a4 100644 > --- a/drivers/block/nbd.c > +++ b/drivers/block/nbd.c > @@ -339,7 +339,7 @@ static int __nbd_set_size(struct nbd_device *nbd, loff_t bytesize, > > lim = queue_limits_start_update(nbd->disk->queue); > if (nbd->config->flags & NBD_FLAG_SEND_TRIM) > - lim.max_hw_discard_sectors = UINT_MAX; > + lim.max_hw_discard_sectors = UINT_MAX / blksize; We use 512 as the "sectors" measurement throughout the block layer, so our limit is actually UINT32_MAX >> 9 since we can only send at most UINT32_MAX as our length. Fix it to be that for both patches and you should be good. Thanks, Josef
On 2024/08/07 6:56, Josef Bacik wrote: > On Tue, Aug 06, 2024 at 03:30:56PM +0200, Wouter Verhelst wrote: >> The version of the NBD protocol implemented by the kernel driver >> currently has a 32 bit field for length values. As the NBD protocol uses >> bytes as a unit of length, length values larger than 2^32 bytes cannot >> be expressed. >> >> Update the max_hw_discard_sectors field to match that. >> >> Signed-off-by: Wouter Verhelst <w@uter.be> >> Fixes: 268283244c0f018dec8bf4a9c69ce50684561f46 >> --- >> drivers/block/nbd.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c >> index 20e9f9fdeaae..1457f0c8a4a4 100644 >> --- a/drivers/block/nbd.c >> +++ b/drivers/block/nbd.c >> @@ -339,7 +339,7 @@ static int __nbd_set_size(struct nbd_device *nbd, loff_t bytesize, >> >> lim = queue_limits_start_update(nbd->disk->queue); >> if (nbd->config->flags & NBD_FLAG_SEND_TRIM) >> - lim.max_hw_discard_sectors = UINT_MAX; >> + lim.max_hw_discard_sectors = UINT_MAX / blksize; > > We use 512 as the "sectors" measurement throughout the block layer, so our limit > is actually > > UINT32_MAX >> 9 UINT_MAX >> SECTOR_SHIFT would be better. > > since we can only send at most UINT32_MAX as our length. Fix it to be that for > both patches and you should be good. Thanks, > > Josef >
Hi Josef, On Wed, Aug 07, 2024 at 09:56:25AM -0400, Josef Bacik wrote: > We use 512 as the "sectors" measurement throughout the block layer, so our limit > is actually > > UINT32_MAX >> 9 > > since we can only send at most UINT32_MAX as our length. Fix it to be that for > both patches and you should be good. Thanks, My first stab actually used UINT32_MAX, but that didn't compile. I investigated and found that for the kernel, UINT32_MAX and UINT_MAX are actually the same, but in order for me to be able to use UINT32_MAX (or U32_MAX, which is also defined to the same value), I would need extra includes. So I'll stick with the UINT_MAX >> SECTOR_SHIFT definition that Damien suggested. Thanks,
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 20e9f9fdeaae..1457f0c8a4a4 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -339,7 +339,7 @@ static int __nbd_set_size(struct nbd_device *nbd, loff_t bytesize, lim = queue_limits_start_update(nbd->disk->queue); if (nbd->config->flags & NBD_FLAG_SEND_TRIM) - lim.max_hw_discard_sectors = UINT_MAX; + lim.max_hw_discard_sectors = UINT_MAX / blksize; else lim.max_hw_discard_sectors = 0; if (!(nbd->config->flags & NBD_FLAG_SEND_FLUSH)) {
The version of the NBD protocol implemented by the kernel driver currently has a 32 bit field for length values. As the NBD protocol uses bytes as a unit of length, length values larger than 2^32 bytes cannot be expressed. Update the max_hw_discard_sectors field to match that. Signed-off-by: Wouter Verhelst <w@uter.be> Fixes: 268283244c0f018dec8bf4a9c69ce50684561f46 --- drivers/block/nbd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)