nfs4.1: fix several problems with _pnfs_return_layout

_pnfs_return_layout had the following problems:

- it did not call pnfs_free_lseg_list on all paths
- it unintentionally did a forgetful return when there was no outstanding io
- it raced with concurrent LAYOUTGETS

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

2 files changed, 9 insertions, 7 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 289c539bd6b3..5879b23e0c99 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5706,6 +5706,7 @@ static void nfs4_layoutreturn_done(struct rpc_task *task, void *calldata)
 {
         struct nfs4_layoutreturn *lrp = calldata;
         struct nfs_server *server;
+        struct pnfs_layout_hdr *lo = NFS_I(lrp->args.inode)->layout;
 
         dprintk("--> %s\n", __func__);
 
@@ -5717,16 +5718,15 @@ static void nfs4_layoutreturn_done(struct rpc_task *task, void *calldata)
                 nfs_restart_rpc(task, lrp->clp);
                 return;
         }
+        spin_lock(&lo->plh_inode->i_lock);
         if (task->tk_status == 0) {
-                struct pnfs_layout_hdr *lo = NFS_I(lrp->args.inode)->layout;
-
                 if (lrp->res.lrs_present) {
-                        spin_lock(&lo->plh_inode->i_lock);
                         pnfs_set_layout_stateid(lo, &lrp->res.stateid, true);
-                        spin_unlock(&lo->plh_inode->i_lock);
                 } else
                         BUG_ON(!list_empty(&lo->plh_segs));
         }
+        lo->plh_block_lgets--;
+        spin_unlock(&lo->plh_inode->i_lock);
         dprintk("<-- %s\n", __func__);
 }
 
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 8c1309d852a6..25de6b27bdf4 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -634,12 +634,14 @@ _pnfs_return_layout(struct inode *ino)
 
         spin_lock(&ino->i_lock);
         lo = nfsi->layout;
-        if (!lo || !mark_matching_lsegs_invalid(lo, &tmp_list, NULL)) {
+        if (!lo) {
                 spin_unlock(&ino->i_lock);
-                dprintk("%s: no layout segments to return\n", __func__);
-                goto out;
+                dprintk("%s: no layout to return\n", __func__);
+                return status;
         }
         stateid = nfsi->layout->plh_stateid;
+        mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
+        lo->plh_block_lgets++;
         /* Reference matched in nfs4_layoutreturn_release */
         get_layout_hdr(lo);
         spin_unlock(&ino->i_lock);