Re: git: b92b9da33006 - main - nfsd: Allow vfs.nfsd.srvmaxio to be up to 4Mbytes

On Friday, May 15, 2026, Oliver Pinter <oliver.pntr@gmail.com> wrote:

> Hi!
>
> On Friday, May 15, 2026, Rick Macklem <rmacklem@freebsd.org> wrote:
>
>> The branch main has been updated by rmacklem:
>>
>> URL: https://cgit.FreeBSD.org/src/commit/?id=b92b9da3300655c86dcd
>> 42ea8a5ba45badd90847
>>
>> commit b92b9da3300655c86dcd42ea8a5ba45badd90847
>> Author:     Rick Macklem <rmacklem@FreeBSD.org>
>> AuthorDate: 2026-05-14 22:33:23 +0000
>> Commit:     Rick Macklem <rmacklem@FreeBSD.org>
>> CommitDate: 2026-05-14 22:33:23 +0000
>>
>>     nfsd: Allow vfs.nfsd.srvmaxio to be up to 4Mbytes
>>
>>     Without this patch, the maximum setting for
>>     vfs.nfsd.srvmaxio was 1Mbyte.  This patch increases
>>     that to 4Mbytes.
>>
>>     The same as for any setting above 128Kbytes, settings up to
>>     4Mbytes require that kern.ipc.maxsockbuf be increased.
>>     (A message generated after setting vfs.nfsd.srvmaxio via
>>     the /etc/rc.conf variable nfs_server_maxio will indicate
>>     the minimum setting, which will be somewhat greater than
>>     four times the setting of vfs.nfsd.srvmaxio.)
>>
>>     Requested by:   Cedric Blancher <cedric.blancher@gmail.com>
>>     MFC after:      2 weeks
>>     Fixes:  13d3bd165e22 ("subr_uio.c: Remove a KASSERT() for large NFS
>> server I/O")
>
>
> Wouldn't be better to introduce an MFC with tag, rater than abusing the
> Fixes tag? This seems to me like a new "feature", rather than a bug. And it
> will may be added to releasenotes also.
>
>

(sorry, I've just seen now, the release notes, I'm going through on the
commit from oldest to newest, but the other part is still relevant)


> ---
>>  sys/fs/nfs/nfsproto.h           | 3 +++
>>  sys/fs/nfsserver/nfs_nfsdport.c | 5 +++--
>>  2 files changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/sys/fs/nfs/nfsproto.h b/sys/fs/nfs/nfsproto.h
>> index 6e67c5be3416..1054c85d8e8f 100644
>> --- a/sys/fs/nfs/nfsproto.h
>> +++ b/sys/fs/nfs/nfsproto.h
>> @@ -89,8 +89,11 @@
>>   * It used to be called NFS_MAXDATA, but has been renamed to clarify that
>>   * it refers to server side only and doesn't conflict with the
>> NFS_MAXDATA
>>   * defined in rpcsvc/nfs_prot.h for userland.
>> + * NFS_SRVMAXIO is the default setting for vfs.nfsd.srvmaxio
>> + * NFS_SRVLIMITIO is the maximum setting allowed for vfs.nfsd.srvmaxio
>>   */
>>  #define        NFS_SRVMAXIO    (128 * 1024)
>> +#define        NFS_SRVLIMITIO  (4 * 1024 * 1024)
>>
>>  /* Stat numbers for rpc returns (version 2, 3 and 4) */
>>  /*
>> diff --git a/sys/fs/nfsserver/nfs_nfsdport.c
>> b/sys/fs/nfsserver/nfs_nfsdport.c
>> index e42d5ca1e0a3..1e6936ed351c 100644
>> --- a/sys/fs/nfsserver/nfs_nfsdport.c
>> +++ b/sys/fs/nfsserver/nfs_nfsdport.c
>> @@ -241,8 +241,9 @@ sysctl_srvmaxio(SYSCTL_HANDLER_ARGS)
>>                 printf("nfsd: vfs.nfsd.srvmaxio can only be increased\n");
>>                 return (EINVAL);
>>         }
>> -       if (newsrvmaxio > 1048576) {
>> -               printf("nfsd: vfs.nfsd.srvmaxio cannot be > 1Mbyte\n");
>> +       if (newsrvmaxio > NFS_SRVLIMITIO) {
>> +               printf("nfsd: vfs.nfsd.srvmaxio cannot be > %d\n",
>> +                   NFS_SRVLIMITIO);
>>                 return (EINVAL);
>>         }
>>         if ((newsrvmaxio & (newsrvmaxio - 1)) != 0) {
>>
>>