NFS: Clean up the pNFS layoutget interface

Ensure that we do return errors from nfs4_proc_layoutget() and that we
don't mark the layout as having failed if the error was due to a
signal or resource problem on the client side.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 27 insertions, 16 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index cf2fd5d0c1b3..1c8656f8745c 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -6286,7 +6286,8 @@ static const struct rpc_call_ops nfs4_layoutget_call_ops = {
         .rpc_release = nfs4_layoutget_release,
 };
 
-void nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags)
+struct pnfs_layout_segment *
+nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags)
 {
         struct nfs_server *server = NFS_SERVER(lgp->args.inode);
         size_t max_pages = max_response_pages(server);
@@ -6303,6 +6304,7 @@ void nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags)
                 .callback_data = lgp,
                 .flags = RPC_TASK_ASYNC,
         };
+        struct pnfs_layout_segment *lseg = NULL;
         int status = 0;
 
         dprintk("--> %s\n", __func__);
@@ -6310,7 +6312,7 @@ void nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags)
         lgp->args.layout.pages = nfs4_alloc_pages(max_pages, gfp_flags);
         if (!lgp->args.layout.pages) {
                 nfs4_layoutget_release(lgp);
-                return;
+                return ERR_PTR(-ENOMEM);
         }
         lgp->args.layout.pglen = max_pages * PAGE_SIZE;
 
@@ -6319,15 +6321,17 @@ void nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags)
         nfs41_init_sequence(&lgp->args.seq_args, &lgp->res.seq_res, 0);
         task = rpc_run_task(&task_setup_data);
         if (IS_ERR(task))
-                return;
+                return ERR_CAST(task);
         status = nfs4_wait_for_completion_rpc_task(task);
         if (status == 0)
                 status = task->tk_status;
         if (status == 0)
-                status = pnfs_layout_process(lgp);
+                lseg = pnfs_layout_process(lgp);
         rpc_put_task(task);
         dprintk("<-- %s status=%d\n", __func__, status);
-        return;
+        if (status)
+                return ERR_PTR(status);
+        return lseg;
 }
 
 static void
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 2e00feacd4be..3a7ac97020df 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -582,7 +582,7 @@ send_layoutget(struct pnfs_layout_hdr *lo,
         struct inode *ino = lo->plh_inode;
         struct nfs_server *server = NFS_SERVER(ino);
         struct nfs4_layoutget *lgp;
-        struct pnfs_layout_segment *lseg = NULL;
+        struct pnfs_layout_segment *lseg;
 
         dprintk("--> %s\n", __func__);
 
@@ -599,16 +599,22 @@ send_layoutget(struct pnfs_layout_hdr *lo,
         lgp->args.type = server->pnfs_curr_ld->id;
         lgp->args.inode = ino;
         lgp->args.ctx = get_nfs_open_context(ctx);
-        lgp->lsegpp = &lseg;
         lgp->gfp_flags = gfp_flags;
 
         /* Synchronously retrieve layout information from server and
          * store in lseg.
          */
-        nfs4_proc_layoutget(lgp, gfp_flags);
-        if (!lseg) {
-                /* remember that LAYOUTGET failed and suspend trying */
-                set_bit(lo_fail_bit(range->iomode), &lo->plh_flags);
+        lseg = nfs4_proc_layoutget(lgp, gfp_flags);
+        if (IS_ERR(lseg)) {
+                switch (PTR_ERR(lseg)) {
+                case -ENOMEM:
+                case -ERESTARTSYS:
+                        break;
+                default:
+                        /* remember that LAYOUTGET failed and suspend trying */
+                        set_bit(lo_fail_bit(range->iomode), &lo->plh_flags);
+                }
+                return NULL;
         }
 
         return lseg;
@@ -1096,7 +1102,7 @@ out_unlock:
 }
 EXPORT_SYMBOL_GPL(pnfs_update_layout);
 
-int
+struct pnfs_layout_segment *
 pnfs_layout_process(struct nfs4_layoutget *lgp)
 {
         struct pnfs_layout_hdr *lo = NFS_I(lgp->args.inode)->layout;
@@ -1129,7 +1135,7 @@ pnfs_layout_process(struct nfs4_layoutget *lgp)
         }
         init_lseg(lo, lseg);
         lseg->pls_range = res->range;
-        *lgp->lsegpp = get_lseg(lseg);
+        get_lseg(lseg);
         pnfs_insert_layout(lo, lseg);
 
         if (res->return_on_close) {
@@ -1140,8 +1146,9 @@ pnfs_layout_process(struct nfs4_layoutget *lgp)
         /* Done processing layoutget. Set the layout stateid */
         pnfs_set_layout_stateid(lo, &res->stateid, false);
         spin_unlock(&ino->i_lock);
+        return lseg;
 out:
-        return status;
+        return ERR_PTR(status);
 
 out_forget_reply:
         spin_unlock(&ino->i_lock);
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 745aa1b39e7c..d51ef888e71b 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -172,7 +172,7 @@ extern int nfs4_proc_getdevicelist(struct nfs_server *server,
                                    struct pnfs_devicelist *devlist);
 extern int nfs4_proc_getdeviceinfo(struct nfs_server *server,
                                    struct pnfs_device *dev);
-extern void nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags);
+extern struct pnfs_layout_segment* nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags);
 extern int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp);
 
 /* pnfs.c */
@@ -192,7 +192,7 @@ void pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *, struct nfs_page
 int pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc);
 bool pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev, struct nfs_page *req);
 void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg);
-int pnfs_layout_process(struct nfs4_layoutget *lgp);
+struct pnfs_layout_segment *pnfs_layout_process(struct nfs4_layoutget *lgp);
 void pnfs_free_lseg_list(struct list_head *tmp_list);
 void pnfs_destroy_layout(struct nfs_inode *);
 void pnfs_destroy_all_layouts(struct nfs_client *);