nfsd: use i_wrlock instead of rcu for nfsdfs i_private (dc46bba7) · Commits · 戴 / test

synchronize_rcu() gets called multiple times each time a client is destroyed. If the laundromat thread has a lot of clients to destroy, the delay can be noticeable. This was causing pynfs test RENEW3 to fail. We could embed an rcu_head in each inode and do the kref_put in an rcu callback. But simplest is just to take a lock here. (I also wonder if the laundromat thread would be better replaced by a bunch of scheduled work or timers or something.) Signed-off-by:

J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfsctl.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -1215,11 +1215,9 @@ static void clear_ncl(struct inode *inode)
		struct nfsdfs_client *ncl = inode->i_private;

		inode->i_private = NULL;
		synchronize_rcu();
		kref_put(&ncl->cl_ref, ncl->cl_release);
		}


		static struct nfsdfs_client __get_nfsdfs_client(struct inode inode)
		{
		struct nfsdfs_client *nc = inode->i_private;
		@@ -1233,9 +1231,9 @@ struct nfsdfs_client get_nfsdfs_client(struct inode inode)
		{
		struct nfsdfs_client *nc;

		rcu_read_lock();
		inode_lock_shared(inode);
		nc = __get_nfsdfs_client(inode);
		rcu_read_unlock();
		inode_unlock_shared(inode);
		return nc;
		}
		/* from __rpc_unlink */

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