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>

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 33273b3..7ac5be3 100644 (file)
--- 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;