pnfs: make pnfs_layout_process more robust

It can return NULL if layoutgets are blocked currently. Fix it to return
-EAGAIN in that case, so we can properly handle it in pnfs_update_layout.

Also, clean up and simplify the error handling -- eliminate "status" and
just use "lseg".

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 11 insertions, 16 deletions

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 46339a7fb191..79ae3049608d 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1708,21 +1708,19 @@ pnfs_layout_process(struct nfs4_layoutget *lgp)
         struct pnfs_layout_segment *lseg;
         struct inode *ino = lo->plh_inode;
         LIST_HEAD(free_me);
-        int status = -EINVAL;
 
         if (!pnfs_sanity_check_layout_range(&res->range))
-                goto out;
+                return ERR_PTR(-EINVAL);
 
         /* Inject layout blob into I/O device driver */
         lseg = NFS_SERVER(ino)->pnfs_curr_ld->alloc_lseg(lo, res, lgp->gfp_flags);
-        if (!lseg || IS_ERR(lseg)) {
+        if (IS_ERR_OR_NULL(lseg)) {
                 if (!lseg)
-                        status = -ENOMEM;
-                else
-                        status = PTR_ERR(lseg);
-                dprintk("%s: Could not allocate layout: error %d\n",
-                       __func__, status);
-                goto out;
+                        lseg = ERR_PTR(-ENOMEM);
+
+                dprintk("%s: Could not allocate layout: error %ld\n",
+                       __func__, PTR_ERR(lseg));
+                return lseg;
         }
 
         init_lseg(lo, lseg);
@@ -1732,15 +1730,14 @@ pnfs_layout_process(struct nfs4_layoutget *lgp)
         spin_lock(&ino->i_lock);
         if (pnfs_layoutgets_blocked(lo)) {
                 dprintk("%s forget reply due to state\n", __func__);
-                goto out_forget_reply;
+                goto out_forget;
         }
 
         if (nfs4_stateid_match_other(&lo->plh_stateid, &res->stateid)) {
                 /* existing state ID, make sure the sequence number matches. */
                 if (pnfs_layout_stateid_blocked(lo, &res->stateid)) {
                         dprintk("%s forget reply due to sequence\n", __func__);
-                        status = -EAGAIN;
-                        goto out_forget_reply;
+                        goto out_forget;
                 }
                 pnfs_set_layout_stateid(lo, &res->stateid, false);
         } else {
@@ -1766,14 +1763,12 @@ pnfs_layout_process(struct nfs4_layoutget *lgp)
         spin_unlock(&ino->i_lock);
         pnfs_free_lseg_list(&free_me);
         return lseg;
-out:
-        return ERR_PTR(status);
 
-out_forget_reply:
+out_forget:
         spin_unlock(&ino->i_lock);
         lseg->pls_layout = lo;
         NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
-        goto out;
+        return ERR_PTR(-EAGAIN);
 }
 
 static void