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

The branch main has been updated by rmacklem:

URL: https://cgit.FreeBSD.org/src/commit/?id=b92b9da3300655c86dcd42ea8a5ba45badd90847

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")
---
 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) {