[PATCH 1/2] NFSv4: Return NFS4ERR_DELAY when a delegation recall fails due to igrab()

[PATCH 1/2] NFSv4: Return NFS4ERR_DELAY when a delegation recall fails due to igrab()

[Trond Myklebust]

If the attempt to recall the delegation fails because the inode is
in the process of being evicted from cache, then use NFS4ERR_DELAY
to ask the server to retry later.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/callback_proc.c |  8 ++++++--
 fs/nfs/delegation.c    | 16 +++++++++-------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index d561161b7c3e..407b2d05579f 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -40,7 +40,9 @@ __be32 nfs4_callback_getattr(void *argp, void *resp,
 		rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
 
 	inode = nfs_delegation_find_inode(cps->clp, &args->fh);
-	if (inode == NULL) {
+	if (IS_ERR(inode)) {
+		if (inode == PTR_ERR(-EAGAIN))
+			res->status = htonl(NFS4ERR_DELAY);
 		trace_nfs4_cb_getattr(cps->clp, &args->fh, NULL,
 				-ntohl(res->status));
 		goto out;
@@ -86,7 +88,9 @@ __be32 nfs4_callback_recall(void *argp, void *resp,
 
 	res = htonl(NFS4ERR_BADHANDLE);
 	inode = nfs_delegation_find_inode(cps->clp, &args->fh);
-	if (inode == NULL) {
+	if (IS_ERR(inode)) {
+		if (inode == PTR_ERR(-EAGAIN))
+			res = htonl(NFS4ERR_DELAY);
 		trace_nfs4_cb_recall(cps->clp, &args->fh, NULL,
 				&args->stateid, -ntohl(res));
 		goto out;
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 91c3737d69df..4b845d2fdb81 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -849,19 +849,21 @@ nfs_delegation_find_inode_server(struct nfs_server *server,
 				 const struct nfs_fh *fhandle)
 {
 	struct nfs_delegation *delegation;
-	struct inode *res = NULL;
+	struct inode *res;
 
 	list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
 		spin_lock(&delegation->lock);
 		if (delegation->inode != NULL &&
 		    nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 			res = igrab(delegation->inode);
+			if (res == NULL)
+				res = ERR_PTR(-EAGAIN);
 		}
 		spin_unlock(&delegation->lock);
 		if (res != NULL)
-			break;
+			return res;
 	}
-	return res;
+	return ERR_PTR(-ENOENT);
 }
 
 /**
@@ -876,16 +878,16 @@ struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 					const struct nfs_fh *fhandle)
 {
 	struct nfs_server *server;
-	struct inode *res = NULL;
+	struct inode *res;
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 		res = nfs_delegation_find_inode_server(server, fhandle);
-		if (res != NULL)
-			break;
+		if (res != ERR_PTR(-ENOENT))
+			return res;
 	}
 	rcu_read_unlock();
-	return res;
+	return ERR_PTR(-ENOENT);
 }
 
 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
-- 
2.17.1

[PATCH 2/2] NFSv4: Return NFS4ERR_DELAY when a layout recall fails due to igrab()

[Trond Myklebust]

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/callback_proc.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 407b2d05579f..124a7c157dff 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -128,7 +128,6 @@ static struct inode *nfs_layout_find_inode_by_stateid(struct nfs_client *clp,
 	struct inode *inode;
 	struct pnfs_layout_hdr *lo;
 
-restart:
 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 		list_for_each_entry(lo, &server->layouts, plh_layouts) {
 			if (stateid != NULL &&
@@ -136,20 +135,20 @@ static struct inode *nfs_layout_find_inode_by_stateid(struct nfs_client *clp,
 				continue;
 			inode = igrab(lo->plh_inode);
 			if (!inode)
-				continue;
+				return ERR_PTR(-EAGAIN);
 			if (!nfs_sb_active(inode->i_sb)) {
 				rcu_read_unlock();
 				spin_unlock(&clp->cl_lock);
 				iput(inode);
 				spin_lock(&clp->cl_lock);
 				rcu_read_lock();
-				goto restart;
+				return ERR_PTR(-EAGAIN);
 			}
 			return inode;
 		}
 	}
 
-	return NULL;
+	return ERR_PTR(-ENOENT);
 }
 
 /*
@@ -166,7 +165,6 @@ static struct inode *nfs_layout_find_inode_by_fh(struct nfs_client *clp,
 	struct inode *inode;
 	struct pnfs_layout_hdr *lo;
 
-restart:
 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 		list_for_each_entry(lo, &server->layouts, plh_layouts) {
 			nfsi = NFS_I(lo->plh_inode);
@@ -176,20 +174,20 @@ static struct inode *nfs_layout_find_inode_by_fh(struct nfs_client *clp,
 				continue;
 			inode = igrab(lo->plh_inode);
 			if (!inode)
-				continue;
+				return ERR_PTR(-EAGAIN);
 			if (!nfs_sb_active(inode->i_sb)) {
 				rcu_read_unlock();
 				spin_unlock(&clp->cl_lock);
 				iput(inode);
 				spin_lock(&clp->cl_lock);
 				rcu_read_lock();
-				goto restart;
+				return ERR_PTR(-EAGAIN);
 			}
 			return inode;
 		}
 	}
 
-	return NULL;
+	return ERR_PTR(-ENOENT);
 }
 
 static struct inode *nfs_layout_find_inode(struct nfs_client *clp,
@@ -201,7 +199,7 @@ static struct inode *nfs_layout_find_inode(struct nfs_client *clp,
 	spin_lock(&clp->cl_lock);
 	rcu_read_lock();
 	inode = nfs_layout_find_inode_by_stateid(clp, stateid);
-	if (!inode)
+	if (inode == ERR_PTR(-ENOENT))
 		inode = nfs_layout_find_inode_by_fh(clp, fh);
 	rcu_read_unlock();
 	spin_unlock(&clp->cl_lock);
@@ -256,8 +254,11 @@ static u32 initiate_file_draining(struct nfs_client *clp,
 	LIST_HEAD(free_me_list);
 
 	ino = nfs_layout_find_inode(clp, &args->cbl_fh, &args->cbl_stateid);
-	if (!ino)
-		goto out;
+	if (IS_ERR(ino)) {
+		if (ino == ERR_PTR(-EAGAIN))
+			rv = NFS4ERR_DELAY;
+		goto out_noput;
+	}
 
 	pnfs_layoutcommit_inode(ino, false);
 
@@ -303,9 +304,10 @@ static u32 initiate_file_draining(struct nfs_client *clp,
 	nfs_commit_inode(ino, 0);
 	pnfs_put_layout_hdr(lo);
 out:
+	nfs_iput_and_deactive(ino);
+out_noput:
 	trace_nfs4_cb_layoutrecall_file(clp, &args->cbl_fh, ino,
 			&args->cbl_stateid, -rv);
-	nfs_iput_and_deactive(ino);
 	return rv;
 }
 
-- 
2.17.1