pnfs: layout roc code

A layout can request return-on-close.  How this interacts with the
forgetful model of never sending LAYOUTRETURNS is a bit ambiguous.
We forget any layouts marked roc, and wait for them to be completely
forgotten before continuing with the close.  In addition, to compensate
for races with any inflight LAYOUTGETs, and the fact that we do not get
any layout stateid back from the server, we set the barrier to the worst
case scenario of current_seqid + number of outstanding LAYOUTGETS.

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

1 files changed, 29 insertions, 0 deletions

diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index f91d0d45551..e2612ea0cbe 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -32,6 +32,7 @@
 
 enum {
         NFS_LSEG_VALID = 0,     /* cleared when lseg is recalled/returned */
+        NFS_LSEG_ROC,           /* roc bit received from server */
 };
 
 struct pnfs_layout_segment {
@@ -50,6 +51,7 @@ enum {
         NFS_LAYOUT_RO_FAILED = 0,       /* get ro layout failed stop trying */
         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 */
 };
 
@@ -72,6 +74,7 @@ struct pnfs_layout_hdr {
         struct list_head        plh_segs;      /* layout segments list */
         nfs4_stateid            plh_stateid;
         atomic_t                plh_outstanding; /* number of RPCs out */
+        unsigned long           plh_block_lgets; /* block LAYOUTGET if >0 */
         u32                     plh_barrier; /* ignore lower seqids */
         unsigned long           plh_flags;
         struct inode            *plh_inode;
@@ -162,6 +165,10 @@ int pnfs_choose_layoutget_stateid(nfs4_stateid *dst,
 int mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
                                 struct list_head *tmp_list,
                                 u32 iomode);
+bool pnfs_roc(struct inode *ino);
+void pnfs_roc_release(struct inode *ino);
+void pnfs_roc_set_barrier(struct inode *ino, u32 barrier);
+bool pnfs_roc_drain(struct inode *ino, u32 *barrier);
 
 
 static inline int lo_fail_bit(u32 iomode)
@@ -193,6 +200,28 @@ pnfs_update_layout(struct inode *ino, struct nfs_open_context *ctx,
         return NULL;
 }
 
+static inline bool
+pnfs_roc(struct inode *ino)
+{
+        return false;
+}
+
+static inline void
+pnfs_roc_release(struct inode *ino)
+{
+}
+
+static inline void
+pnfs_roc_set_barrier(struct inode *ino, u32 barrier)
+{
+}
+
+static inline bool
+pnfs_roc_drain(struct inode *ino, u32 *barrier)
+{
+        return false;
+}
+
 static inline void set_pnfs_layoutdriver(struct nfs_server *s, u32 id)
 {
 }