This is a note to let you know that I've just added the patch titled
NFSD: Increase NFSD_MAX_OPS_PER_COMPOUND
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-increase-nfsd_max_ops_per_compound.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f3b9d5fbf4ea5534fcb7090b2aaf60db9f54fa9b
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: Fri Sep 2 18:18:16 2022 -0400
NFSD: Increase NFSD_MAX_OPS_PER_COMPOUND
[ Upstream commit 80e591ce636f3ae6855a0ca26963da1fdd6d4508 ]
When attempting an NFSv4 mount, a Solaris NFSv4 client builds a
single large COMPOUND that chains a series of LOOKUPs to get to the
pseudo filesystem root directory that is to be mounted. The Linux
NFS server's current maximum of 16 operations per NFSv4 COMPOUND is
not large enough to ensure that this works for paths that are more
than a few components deep.
Since NFSD_MAX_OPS_PER_COMPOUND is mostly a sanity check, and most
NFSv4 COMPOUNDS are between 3 and 6 operations (thus they do not
trigger any re-allocation of the operation array on the server),
increasing this maximum should result in little to no impact.
The ops array can get large now, so allocate it via vmalloc() to
help ensure memory fragmentation won't cause an allocation failure.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216383
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 5aafbd0f7ae30..0f30d93577e7b 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -42,6 +42,8 @@
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/sunrpc/addr.h>
#include <linux/xattr.h>
+#include <linux/vmalloc.h>
+
#include <uapi/linux/xattr.h>
#include "idmap.h"
@@ -2364,10 +2366,9 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
NFSD_MAX_OPS_PER_COMPOUND);
if (argp->opcnt > ARRAY_SIZE(argp->iops)) {
- argp->ops = kzalloc(argp->opcnt * sizeof(*argp->ops), GFP_KERNEL);
+ argp->ops = vcalloc(argp->opcnt, sizeof(*argp->ops));
if (!argp->ops) {
argp->ops = argp->iops;
- dprintk("nfsd: couldn't allocate room for COMPOUND\n");
return false;
}
}
@@ -5399,7 +5400,7 @@ void nfsd4_release_compoundargs(struct svc_rqst *rqstp)
struct nfsd4_compoundargs *args = rqstp->rq_argp;
if (args->ops != args->iops) {
- kfree(args->ops);
+ vfree(args->ops);
args->ops = args->iops;
}
while (args->to_free) {
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index ae596dbf86675..5d28beb290fef 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -175,7 +175,7 @@ static inline struct nfs4_delegation *delegstateid(struct nfs4_stid *s)
/* Maximum number of slots per session. 160 is useful for long haul TCP */
#define NFSD_MAX_SLOTS_PER_SESSION 160
/* Maximum number of operations per session compound */
-#define NFSD_MAX_OPS_PER_COMPOUND 16
+#define NFSD_MAX_OPS_PER_COMPOUND 50
/* Maximum session per slot cache size */
#define NFSD_SLOT_CACHE_SIZE 2048
/* Maximum number of NFSD_SLOT_CACHE_SIZE slots per session */
