nfsd4: decrease nfsd4_encode_fattr stack usage

A struct svc_fh is 320 bytes on x86_64, it'd be better not to have these
on the stack.

kmalloc'ing them probably isn't ideal either, but this is the simplest
thing to do.  If it turns out to be a problem in the readdir case then
we could add a svc_fh to nfsd4_readdir and pass that in.

Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 8198ecf3c03a..63f2395c57ed 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2058,7 +2058,7 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
         u32 bmval1 = bmval[1];
         u32 bmval2 = bmval[2];
         struct kstat stat;
-        struct svc_fh tempfh;
+        struct svc_fh *tempfh = NULL;
         struct kstatfs statfs;
         int buflen = count << 2;
         __be32 *attrlenp;
@@ -2105,11 +2105,15 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
                         goto out_nfserr;
         }
         if ((bmval0 & (FATTR4_WORD0_FILEHANDLE | FATTR4_WORD0_FSID)) && !fhp) {
-                fh_init(&tempfh, NFS4_FHSIZE);
-                status = fh_compose(&tempfh, exp, dentry, NULL);
+                tempfh = kmalloc(sizeof(struct svc_fh), GFP_KERNEL);
+                status = nfserr_jukebox;
+                if (!tempfh)
+                        goto out;
+                fh_init(tempfh, NFS4_FHSIZE);
+                status = fh_compose(tempfh, exp, dentry, NULL);
                 if (status)
                         goto out;
-                fhp = &tempfh;
+                fhp = tempfh;
         }
         if (bmval0 & (FATTR4_WORD0_ACL | FATTR4_WORD0_ACLSUPPORT
                         | FATTR4_WORD0_SUPPORTED_ATTRS)) {
@@ -2495,8 +2499,8 @@ out:
                 security_release_secctx(context, contextlen);
 #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
         kfree(acl);
-        if (fhp == &tempfh)
-                fh_put(&tempfh);
+        if (tempfh)
+                fh_put(tempfh);
         return status;
 out_nfserr:
         status = nfserrno(err);