Commit 2fb4af5e authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Trond Myklebust
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NFS: track active delegations per-server 



The active delegation watermark was added to avoid overloading servers.
Track the active delegation per-server instead of globally so that clients
talking to multiple servers aren't limited by the global limit.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20250718081509.2607553-5-hch@lst.de


Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent aee077d8

fs/nfs/client.c

+1 −0
Original line number Diff line number Diff line
@@ -1005,6 +1005,7 @@ struct nfs_server *nfs_alloc_server(void) 
	INIT_LIST_HEAD(&server->ss_src_copies);



	atomic_set(&server->active, 0);

	atomic_long_set(&server->nr_active_delegations, 0);



	server->io_stats = nfs_alloc_iostats();

	if (!server->io_stats) {

fs/nfs/delegation.c

+19 −16
Original line number Diff line number Diff line
@@ -27,7 +27,6 @@ 


#define NFS_DEFAULT_DELEGATION_WATERMARK (5000U)



static atomic_long_t nfs_active_delegations;

static unsigned nfs_delegation_watermark = NFS_DEFAULT_DELEGATION_WATERMARK;

module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644);
@@ -38,11 +37,12 @@ static void __nfs_free_delegation(struct nfs_delegation *delegation) 
	kfree_rcu(delegation, rcu);

}



static void nfs_mark_delegation_revoked(struct nfs_delegation *delegation)

static void nfs_mark_delegation_revoked(struct nfs_server *server,

		struct nfs_delegation *delegation)

{

	if (!test_and_set_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {

		delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;

		atomic_long_dec(&nfs_active_delegations);

		atomic_long_dec(&server->nr_active_delegations);

		if (!test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))

			nfs_clear_verifier_delegated(delegation->inode);

	}
@@ -60,9 +60,10 @@ static void nfs_put_delegation(struct nfs_delegation *delegation) 
		__nfs_free_delegation(delegation);

}



static void nfs_free_delegation(struct nfs_delegation *delegation)

static void nfs_free_delegation(struct nfs_server *server,

		struct nfs_delegation *delegation)

{

	nfs_mark_delegation_revoked(delegation);

	nfs_mark_delegation_revoked(server, delegation);

	nfs_put_delegation(delegation);

}
@@ -261,7 +262,7 @@ void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred, 
	}

	clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);

	if (test_and_clear_bit(NFS_DELEGATION_REVOKED, &delegation->flags))

		atomic_long_inc(&nfs_active_delegations);

		atomic_long_inc(&NFS_SERVER(inode)->nr_active_delegations);

	spin_unlock(&delegation->lock);

	rcu_read_unlock();

	put_cred(oldcred);
@@ -413,7 +414,8 @@ nfs_update_delegation_cred(struct nfs_delegation *delegation, 
}



static void

nfs_update_inplace_delegation(struct nfs_delegation *delegation,

nfs_update_inplace_delegation(struct nfs_server *server,

		struct nfs_delegation *delegation,

		const struct nfs_delegation *update)

{

	if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
@@ -426,7 +428,7 @@ nfs_update_inplace_delegation(struct nfs_delegation *delegation, 
			nfs_update_delegation_cred(delegation, update->cred);

			/* smp_mb__before_atomic() is implicit due to xchg() */

			clear_bit(NFS_DELEGATION_REVOKED, &delegation->flags);

			atomic_long_inc(&nfs_active_delegations);

			atomic_long_inc(&server->nr_active_delegations);

		}

	}

}
@@ -481,7 +483,7 @@ int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred, 
	if (nfs4_stateid_match_other(&old_delegation->stateid,

				&delegation->stateid)) {

		spin_lock(&old_delegation->lock);

		nfs_update_inplace_delegation(old_delegation,

		nfs_update_inplace_delegation(server, old_delegation,

				delegation);

		spin_unlock(&old_delegation->lock);

		goto out;
@@ -530,7 +532,7 @@ int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred, 
	rcu_assign_pointer(nfsi->delegation, delegation);

	delegation = NULL;



	atomic_long_inc(&nfs_active_delegations);

	atomic_long_inc(&server->nr_active_delegations);



	trace_nfs4_set_delegation(inode, type);
@@ -544,7 +546,7 @@ int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred, 
		__nfs_free_delegation(delegation);

	if (freeme != NULL) {

		nfs_do_return_delegation(inode, freeme, 0);

		nfs_free_delegation(freeme);

		nfs_free_delegation(server, freeme);

	}

	return status;

}
@@ -756,7 +758,7 @@ void nfs_inode_evict_delegation(struct inode *inode) 
		set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);

		set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);

		nfs_do_return_delegation(inode, delegation, 1);

		nfs_free_delegation(delegation);

		nfs_free_delegation(NFS_SERVER(inode), delegation);

	}

}
@@ -842,7 +844,8 @@ void nfs4_inode_return_delegation_on_close(struct inode *inode) 
	if (!delegation)

		goto out;

	if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) ||

	    atomic_long_read(&nfs_active_delegations) >= nfs_delegation_watermark) {

	    atomic_long_read(&NFS_SERVER(inode)->nr_active_delegations) >=

	    nfs_delegation_watermark) {

		spin_lock(&delegation->lock);

		if (delegation->inode &&

		    list_empty(&NFS_I(inode)->open_files) &&
@@ -1018,7 +1021,7 @@ static void nfs_revoke_delegation(struct inode *inode, 
		}

		spin_unlock(&delegation->lock);

	}

	nfs_mark_delegation_revoked(delegation);

	nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);

	ret = true;

out:

	rcu_read_unlock();
@@ -1050,7 +1053,7 @@ void nfs_delegation_mark_returned(struct inode *inode, 
			delegation->stateid.seqid = stateid->seqid;

	}



	nfs_mark_delegation_revoked(delegation);

	nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);

	clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);

	spin_unlock(&delegation->lock);

	if (nfs_detach_delegation(NFS_I(inode), delegation, NFS_SERVER(inode)))
@@ -1270,7 +1273,7 @@ static int nfs_server_reap_unclaimed_delegations(struct nfs_server *server, 
		if (delegation != NULL) {

			if (nfs_detach_delegation(NFS_I(inode), delegation,

						server) != NULL)

				nfs_free_delegation(delegation);

				nfs_free_delegation(server, delegation);

			/* Match nfs_start_delegation_return_locked */

			nfs_put_delegation(delegation);

		}

include/linux/nfs_fs_sb.h

+1 −0
Original line number Diff line number Diff line
@@ -254,6 +254,7 @@ struct nfs_server { 
	struct list_head	state_owners_lru;

	struct list_head	layouts;

	struct list_head	delegations;

	atomic_long_t		nr_active_delegations;

	struct list_head	ss_copies;

	struct list_head	ss_src_copies;