nfsd4: reduce do_open_lookup() stack usage

I get 320 bytes for struct svc_fh on x86_64, really a little large to be
putting on the stack; kmalloc() instead.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 14 insertions, 10 deletions

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index bdb71a57c94e..abe808a52d97 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -193,10 +193,13 @@ static __be32 nfsd_check_obj_isreg(struct svc_fh *fh)
 static __be32
 do_open_lookup(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open)
 {
-        struct svc_fh resfh;
+        struct svc_fh *resfh;
         __be32 status;
 
-        fh_init(&resfh, NFS4_FHSIZE);
+        resfh = kmalloc(sizeof(struct svc_fh), GFP_KERNEL);
+        if (!resfh)
+                return nfserr_jukebox;
+        fh_init(resfh, NFS4_FHSIZE);
         open->op_truncate = 0;
 
         if (open->op_create) {
@@ -221,7 +224,7 @@ do_open_lookup(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_o
                  */
                 status = do_nfsd_create(rqstp, current_fh, open->op_fname.data,
                                         open->op_fname.len, &open->op_iattr,
-                                        &resfh, open->op_createmode,
+                                        resfh, open->op_createmode,
                                         (u32 *)open->op_verf.data,
                                         &open->op_truncate, &open->op_created);
 
@@ -235,28 +238,29 @@ do_open_lookup(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_o
                                                 FATTR4_WORD1_TIME_MODIFY);
         } else {
                 status = nfsd_lookup(rqstp, current_fh,
-                                     open->op_fname.data, open->op_fname.len, &resfh);
+                                     open->op_fname.data, open->op_fname.len, resfh);
                 fh_unlock(current_fh);
                 if (status)
                         goto out;
-                status = nfsd_check_obj_isreg(&resfh);
+                status = nfsd_check_obj_isreg(resfh);
         }
         if (status)
                 goto out;
 
         if (is_create_with_attrs(open) && open->op_acl != NULL)
-                do_set_nfs4_acl(rqstp, &resfh, open->op_acl, open->op_bmval);
+                do_set_nfs4_acl(rqstp, resfh, open->op_acl, open->op_bmval);
 
         /* set reply cache */
         fh_copy_shallow(&open->op_openowner->oo_owner.so_replay.rp_openfh,
-                        &resfh.fh_handle);
+                        &resfh->fh_handle);
         if (!open->op_created)
-                status = do_open_permission(rqstp, &resfh, open,
+                status = do_open_permission(rqstp, resfh, open,
                                             NFSD_MAY_NOP);
         set_change_info(&open->op_cinfo, current_fh);
-        fh_dup2(current_fh, &resfh);
+        fh_dup2(current_fh, resfh);
 out:
-        fh_put(&resfh);
+        fh_put(resfh);
+        kfree(resfh);
         return status;
 }