NFSv4.1: Get rid of the NFS_LAYOUT_DESTROYED state

We already have a mechanism for blocking LAYOUTGET by means of the
plh_block_lgets counter. The only "service" that NFS_LAYOUT_DESTROYED
provides at this point is to block layoutget once the layout segment
list is empty, which basically means that you have to wait until
the pnfs_layout_hdr is destroyed before you can do pNFS on that file
again.

This patch enables the reuse of the pnfs_layout_hdr if the layout
segment list is empty.

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

3 files changed, 2 insertions, 17 deletions

diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index 6cce57e7fe55..52d847212066 100644
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -279,8 +279,7 @@ filelayout_reset_to_mds(struct pnfs_layout_segment *lseg)
 {
         struct nfs4_deviceid_node *node = FILELAYOUT_DEVID_NODE(lseg);
 
-        return pnfs_test_layout_destroyed(lseg->pls_layout) ||
-                filelayout_test_devid_unavailable(node);
+        return filelayout_test_devid_unavailable(node);
 }
 
 /*
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index fcc72ecf2fd7..bda88a275071 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -331,8 +331,6 @@ pnfs_layout_remove_lseg(struct pnfs_layout_hdr *lo,
         list_del_init(&lseg->pls_list);
         /* Matched by pnfs_get_layout_hdr in pnfs_layout_insert_lseg */
         atomic_dec(&lo->plh_refcount);
-        if (list_empty(&lo->plh_segs))
-                set_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags);
         rpc_wake_up(&NFS_SERVER(inode)->roc_rpcwaitq);
 }
 
@@ -463,10 +461,8 @@ pnfs_mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
 
         dprintk("%s:Begin lo %p\n", __func__, lo);
 
-        if (list_empty(&lo->plh_segs)) {
-                set_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags);
+        if (list_empty(&lo->plh_segs))
                 return 0;
-        }
         list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
                 if (!recall_range ||
                     should_free_lseg(&lseg->pls_range, recall_range)) {
@@ -590,7 +586,6 @@ pnfs_layoutgets_blocked(struct pnfs_layout_hdr *lo, nfs4_stateid *stateid,
             (int)(lo->plh_barrier - be32_to_cpu(stateid->seqid)) >= 0)
                 return true;
         return lo->plh_block_lgets ||
-                test_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags) ||
                 test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags) ||
                 (list_empty(&lo->plh_segs) &&
                  (atomic_read(&lo->plh_outstanding) > lget));
@@ -912,8 +907,6 @@ pnfs_find_alloc_layout(struct inode *ino,
         dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout);
 
         if (nfsi->layout) {
-                if (test_bit(NFS_LAYOUT_DESTROYED, &nfsi->layout->plh_flags))
-                        return NULL;
                 pnfs_get_layout_hdr(nfsi->layout);
                 return nfsi->layout;
         }
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index aacda7fbb536..92f6ce6532ba 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -62,7 +62,6 @@ enum {
         NFS_LAYOUT_RW_FAILED,           /* get rw layout failed stop trying */
         NFS_LAYOUT_BULK_RECALL,         /* bulk recall affecting layout */
         NFS_LAYOUT_ROC,                 /* some lseg had roc bit set */
-        NFS_LAYOUT_DESTROYED,           /* no new use of layout allowed */
         NFS_LAYOUT_RETURNED,            /* layout has already been returned */
 };
 
@@ -278,12 +277,6 @@ pnfs_test_layout_returned(struct pnfs_layout_hdr *lo)
         return test_bit(NFS_LAYOUT_RETURNED, &lo->plh_flags);
 }
 
-static inline bool
-pnfs_test_layout_destroyed(struct pnfs_layout_hdr *lo)
-{
-        return test_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags);
-}
-
 static inline struct pnfs_layout_segment *
 pnfs_get_lseg(struct pnfs_layout_segment *lseg)
 {