NFS: Don't allocate nfs_fattr on the stack in __nfs42_ssc_open()

stable inclusion
from stable-v5.10.140
commit 23c6f25a60435f85e1a442dd5492e96a260dd731
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I63FTT

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=23c6f25a60435f85e1a442dd5492e96a260dd731

--------------------------------

[ Upstream commit 156cd285 ]

The preferred behaviour is always to allocate struct nfs_fattr from the
slab.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>

fs/nfs/nfs4file.c

@@ -318,7 +318,7 @@ static int read_name_gen = 1;
 static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
 		struct nfs_fh *src_fh, nfs4_stateid *stateid)
 {
-	struct nfs_fattr fattr;
+	struct nfs_fattr *fattr = nfs_alloc_fattr();
 	struct file *filep, *res;
 	struct nfs_server *server;
 	struct inode *r_ino = NULL;
@@ -329,9 +329,10 @@ static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
 
 	server = NFS_SERVER(ss_mnt->mnt_root->d_inode);
 
-	nfs_fattr_init(&fattr);
+	if (!fattr)
+		return ERR_PTR(-ENOMEM);
 
-	status = nfs4_proc_getattr(server, src_fh, &fattr, NULL, NULL);
+	status = nfs4_proc_getattr(server, src_fh, fattr, NULL, NULL);
 	if (status < 0) {
 		res = ERR_PTR(status);
 		goto out;
@@ -344,7 +345,7 @@ static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
 		goto out;
 	snprintf(read_name, len, SSC_READ_NAME_BODY, read_name_gen++);
 
-	r_ino = nfs_fhget(ss_mnt->mnt_root->d_inode->i_sb, src_fh, &fattr,
+	r_ino = nfs_fhget(ss_mnt->mnt_root->d_inode->i_sb, src_fh, fattr,
 			NULL);
 	if (IS_ERR(r_ino)) {
 		res = ERR_CAST(r_ino);
@@ -389,6 +390,7 @@ static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
 out_free_name:
 	kfree(read_name);
 out:
+	nfs_free_fattr(fattr);
 	return res;
 out_stateowner:
 	nfs4_put_state_owner(sp);