NFS: Ensure that we mark the inode as dirty if we exit early from commit

If we exit from nfs_commit_inode() without ensuring that the COMMIT rpc
call has been completed, we must re-mark the inode as dirty. Otherwise,
future calls to sync_inode() with the WB_SYNC_ALL flag set will fail to
ensure that the data is on the disk.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/write.c

@@ -1386,7 +1386,7 @@ static int nfs_commit_inode(struct inode *inode, int how)
 	int res = 0;
 
 	if (!nfs_commit_set_lock(NFS_I(inode), may_wait))
-		goto out;
+		goto out_mark_dirty;
 	spin_lock(&inode->i_lock);
 	res = nfs_scan_commit(inode, &head, 0, 0);
 	spin_unlock(&inode->i_lock);
@@ -1398,9 +1398,18 @@ static int nfs_commit_inode(struct inode *inode, int how)
 			wait_on_bit(&NFS_I(inode)->flags, NFS_INO_COMMIT,
 					nfs_wait_bit_killable,
 					TASK_KILLABLE);
+		else
+			goto out_mark_dirty;
 	} else
 		nfs_commit_clear_lock(NFS_I(inode));
-out:
+	return res;
+	/* Note: If we exit without ensuring that the commit is complete,
+	 * we must mark the inode as dirty. Otherwise, future calls to
+	 * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure
+	 * that the data is on the disk.
+	 */
+out_mark_dirty:
+	__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 	return res;
 }