NFSv4.1: Remove redundant reference to the pnfs_layout_hdr

Each layout segment already holds a reference to the pnfs_layout_hdr,
so there is no need to hold an extra reference that is released once
the last layout segment is freed.

Ensure that pnfs_find_alloc_layout() always returns a reference
to the pnfs_layout_hdr, which will be matched by the final call to
pnfs_put_layout_hdr() in pnfs_update_layout().

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

1 files changed, 4 insertions, 9 deletions

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 33273b3a330f..7ac5be36f132 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -331,11 +331,8 @@ pnfs_layout_remove_lseg(struct pnfs_layout_hdr *lo,
 
         WARN_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
         list_del_init(&lseg->pls_list);
-        if (list_empty(&lo->plh_segs)) {
+        if (list_empty(&lo->plh_segs))
                 set_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags);
-                /* Matched by initial refcount set in alloc_init_layout_hdr */
-                pnfs_put_layout_hdr_locked(lo);
-        }
         rpc_wake_up(&NFS_SERVER(inode)->roc_rpcwaitq);
 }
 
@@ -468,8 +465,7 @@ pnfs_mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
         dprintk("%s:Begin lo %p\n", __func__, lo);
 
         if (list_empty(&lo->plh_segs)) {
-                if (!test_and_set_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags))
-                        pnfs_put_layout_hdr_locked(lo);
+                set_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags);
                 return 0;
         }
         list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
@@ -929,8 +925,8 @@ pnfs_find_alloc_layout(struct inode *ino,
         if (nfsi->layout) {
                 if (test_bit(NFS_LAYOUT_DESTROYED, &nfsi->layout->plh_flags))
                         return NULL;
-                else
-                        return nfsi->layout;
+                pnfs_get_layout_hdr(nfsi->layout);
+                return nfsi->layout;
         }
         spin_unlock(&ino->i_lock);
         new = alloc_init_layout_hdr(ino, ctx, gfp_flags);
@@ -1129,7 +1125,6 @@ pnfs_update_layout(struct inode *ino,
                 goto out_unlock;
         atomic_inc(&lo->plh_outstanding);
 
-        pnfs_get_layout_hdr(lo);
         if (list_empty(&lo->plh_segs))
                 first = true;