nfs4: serialize layoutcommit

Current pnfs_layoutcommit_inode can not handle parallel layoutcommit.
And as Trond suggested , there is no need for client to optimize for
parallel layoutcommit. So add NFS_INO_LAYOUTCOMMITTING flag to
mark inflight layoutcommit and serialize lalyoutcommit with it.
Also mark_inode_dirty_sync if pnfs_layoutcommit_inode fails to issue
layoutcommit.

Reported-by: Vitaliy Gusev <gusev.vitaliy@nexenta.com>
Signed-off-by: Peng Tao <peng_tao@emc.com>
Signed-off-by: Jim Rees <rees@umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 22 insertions, 3 deletions

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index ee73d9a4f700..a2478bc74442 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1443,17 +1443,31 @@ pnfs_layoutcommit_inode(struct inode *inode, bool sync)
         /* Note kzalloc ensures data->res.seq_res.sr_slot == NULL */
         data = kzalloc(sizeof(*data), GFP_NOFS);
         if (!data) {
-                mark_inode_dirty_sync(inode);
                 status = -ENOMEM;
                 goto out;
         }
 
+        if (!test_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
+                goto out_free;
+
+        if (test_and_set_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags)) {
+                if (!sync) {
+                        status = -EAGAIN;
+                        goto out_free;
+                }
+                status = wait_on_bit_lock(&nfsi->flags, NFS_INO_LAYOUTCOMMITTING,
+                                        nfs_wait_bit_killable, TASK_KILLABLE);
+                if (status)
+                        goto out_free;
+        }
+
         INIT_LIST_HEAD(&data->lseg_list);
         spin_lock(&inode->i_lock);
         if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
+                clear_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags);
                 spin_unlock(&inode->i_lock);
-                kfree(data);
-                goto out;
+                wake_up_bit(&nfsi->flags, NFS_INO_LAYOUTCOMMITTING);
+                goto out_free;
         }
 
         pnfs_list_write_lseg(inode, &data->lseg_list);
@@ -1475,6 +1489,11 @@ pnfs_layoutcommit_inode(struct inode *inode, bool sync)
 
         status = nfs4_proc_layoutcommit(data, sync);
 out:
+        if (status)
+                mark_inode_dirty_sync(inode);
         dprintk("<-- %s status %d\n", __func__, status);
         return status;
+out_free:
+        kfree(data);
+        goto out;
 }