Re: [Qemu-devel] [PATCHv2] block/nfs: cache allocated filesize for read-only files

[Peter Lieven <pl@kamp.de>]

Am 24.08.2015 um 20:39 schrieb Max Reitz:
> On 24.08.2015 10:06, Peter Lieven wrote:
>> If the file is readonly its not expected to grow so
>> save the blocking call to nfs_fstat_async and use
>> the value saved at connection time. Also important
>> the monitor (and thus the main loop) will not hang
>> if block device info is queried and the NFS share
>> is unresponsive.
>>
>> Signed-off-by: Peter Lieven <pl@kamp.de>
>> ---
>> v1->v2: update cache on reopen_prepare [Max]
>>
>>  block/nfs.c | 35 +++++++++++++++++++++++++++++++++++
>>  1 file changed, 35 insertions(+)
> Reviewed-by: Max Reitz <mreitz@redhat.com>
>
> I hope you're ready for the "Stale actual-size value with
> cache=direct,read-only=on,format=raw files on NFS" reports. :-)
actually a good point, maybe the cache should only be used if

!(bs->open_flags & BDRV_O_NOCACHE)

for my cdrom stuff this is still ok.

Peter