[PATCH v8 03/11] NFSv4: Fix open create exclusive when the server reboots

[Trond Myklebust <trond.myklebust@primarydata.com>]

If the server that does not implement NFSv4.1 persistent session
semantics reboots while we are performing an exclusive create,
then the return value of NFS4ERR_DELAY when we replay the open
during the grace period causes us to lose the verifier.
When the grace period expires, and we present a new verifier,
the server will then correctly reply NFS4ERR_EXIST.

This commit ensures that we always present the same verifier when
replaying the OPEN.

Reported-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---
 fs/nfs/nfs4proc.c | 41 ++++++++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index f44eef8c92fe..3309ee35e73c 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1088,6 +1088,12 @@ struct nfs4_opendata {
 	int rpc_status;
 };
 
+struct nfs4_open_createattrs {
+	struct nfs4_label *label;
+	struct iattr *sattr;
+	const __u32 verf[2];
+};
+
 static bool nfs4_clear_cap_atomic_open_v1(struct nfs_server *server,
 		int err, struct nfs4_exception *exception)
 {
@@ -1157,8 +1163,7 @@ static void nfs4_init_opendata_res(struct nfs4_opendata *p)
 
 static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
 		struct nfs4_state_owner *sp, fmode_t fmode, int flags,
-		const struct iattr *attrs,
-		struct nfs4_label *label,
+		const struct nfs4_open_createattrs *c,
 		enum open_claim_type4 claim,
 		gfp_t gfp_mask)
 {
@@ -1166,6 +1171,7 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
 	struct inode *dir = d_inode(parent);
 	struct nfs_server *server = NFS_SERVER(dir);
 	struct nfs_seqid *(*alloc_seqid)(struct nfs_seqid_counter *, gfp_t);
+	struct nfs4_label *label = (c != NULL) ? c->label : NULL;
 	struct nfs4_opendata *p;
 
 	p = kzalloc(sizeof(*p), gfp_mask);
@@ -1231,15 +1237,11 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
 	case NFS4_OPEN_CLAIM_DELEG_PREV_FH:
 		p->o_arg.fh = NFS_FH(d_inode(dentry));
 	}
-	if (attrs != NULL && attrs->ia_valid != 0) {
-		__u32 verf[2];
-
+	if (c != NULL && c->sattr != NULL && c->sattr->ia_valid != 0) {
 		p->o_arg.u.attrs = &p->attrs;
-		memcpy(&p->attrs, attrs, sizeof(p->attrs));
+		memcpy(&p->attrs, c->sattr, sizeof(p->attrs));
 
-		verf[0] = jiffies;
-		verf[1] = current->pid;
-		memcpy(p->o_arg.u.verifier.data, verf,
+		memcpy(p->o_arg.u.verifier.data, c->verf,
 				sizeof(p->o_arg.u.verifier.data));
 	}
 	p->c_arg.fh = &p->o_res.fh;
@@ -1892,7 +1894,7 @@ static struct nfs4_opendata *nfs4_open_recoverdata_alloc(struct nfs_open_context
 	struct nfs4_opendata *opendata;
 
 	opendata = nfs4_opendata_alloc(ctx->dentry, state->owner, 0, 0,
-			NULL, NULL, claim, GFP_NOFS);
+			NULL, claim, GFP_NOFS);
 	if (opendata == NULL)
 		return ERR_PTR(-ENOMEM);
 	opendata->state = state;
@@ -2823,8 +2825,7 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata,
 static int _nfs4_do_open(struct inode *dir,
 			struct nfs_open_context *ctx,
 			int flags,
-			struct iattr *sattr,
-			struct nfs4_label *label,
+			const struct nfs4_open_createattrs *c,
 			int *opened)
 {
 	struct nfs4_state_owner  *sp;
@@ -2836,6 +2837,8 @@ static int _nfs4_do_open(struct inode *dir,
 	struct nfs4_threshold **ctx_th = &ctx->mdsthreshold;
 	fmode_t fmode = ctx->mode & (FMODE_READ|FMODE_WRITE|FMODE_EXEC);
 	enum open_claim_type4 claim = NFS4_OPEN_CLAIM_NULL;
+	struct iattr *sattr = c->sattr;
+	struct nfs4_label *label = c->label;
 	struct nfs4_label *olabel = NULL;
 	int status;
 
@@ -2854,8 +2857,8 @@ static int _nfs4_do_open(struct inode *dir,
 	status = -ENOMEM;
 	if (d_really_is_positive(dentry))
 		claim = NFS4_OPEN_CLAIM_FH;
-	opendata = nfs4_opendata_alloc(dentry, sp, fmode, flags, sattr,
-			label, claim, GFP_KERNEL);
+	opendata = nfs4_opendata_alloc(dentry, sp, fmode, flags,
+			c, claim, GFP_KERNEL);
 	if (opendata == NULL)
 		goto err_put_state_owner;
 
@@ -2936,10 +2939,18 @@ static struct nfs4_state *nfs4_do_open(struct inode *dir,
 	struct nfs_server *server = NFS_SERVER(dir);
 	struct nfs4_exception exception = { };
 	struct nfs4_state *res;
+	struct nfs4_open_createattrs c = {
+		.label = label,
+		.sattr = sattr,
+		.verf = {
+			[0] = (__u32)jiffies,
+			[1] = (__u32)current->pid,
+		},
+	};
 	int status;
 
 	do {
-		status = _nfs4_do_open(dir, ctx, flags, sattr, label, opened);
+		status = _nfs4_do_open(dir, ctx, flags, &c, opened);
 		res = ctx->state;
 		trace_nfs4_open_file(ctx, flags, status);
 		if (status == 0)
-- 
2.13.6