nfs/localio: use read_seqbegin() rather than read_seqbegin_or_lock()

The usage of read_seqbegin_or_lock() in nfs_copy_boot_verifier()
is wrong. "seq" is always even and thus "or_lock" has no effect.

nfs_copy_boot_verifier() just copies 8 bytes and is supposed to be
very rare operation, so we do not need the adaptive locking in this case.

Signed-off-by: Li RongQing <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Trond Myklebust <[email protected]>

Author: lrq-max

fs/nfs/localio.c

@@ -500,14 +500,13 @@ nfs_copy_boot_verifier(struct nfs_write_verifier *verifier, struct inode *inode)
 {
 	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 	u32 *verf = (u32 *)verifier->data;
-	int seq = 0;
+	unsigned int seq;
 
 	do {
-		read_seqbegin_or_lock(&clp->cl_boot_lock, &seq);
+		seq = read_seqbegin(&clp->cl_boot_lock);
 		verf[0] = (u32)clp->cl_nfssvc_boot.tv_sec;
 		verf[1] = (u32)clp->cl_nfssvc_boot.tv_nsec;
-	} while (need_seqretry(&clp->cl_boot_lock, seq));
-	done_seqretry(&clp->cl_boot_lock, seq);
+	} while (read_seqretry(&clp->cl_boot_lock, seq));
 }
 
 static void