orangefs: hopefully saner op refcounting and locking

* create with refcount 1
* make op_release() decrement and free if zero (i.e. old put_op()
  has become that).
* mark when submitter has given up waiting; from that point nobody
  else can move between the lists, change state, etc.
* have daemon read/write_iter grab a reference when picking op
  and *always* give it up in the end
* don't put into hash until we know it's been successfully passed to
  daemon

* move op->lock _lower_ than htab_in_progress_lock (and make sure
  to take it in purge_inprogress_ops())

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>

1 files changed, 5 insertions, 12 deletions

diff --git a/fs/orangefs/file.c b/fs/orangefs/file.c
index 171013ae0036..df3404ba60af 100644
--- a/fs/orangefs/file.c
+++ b/fs/orangefs/file.c
@@ -105,10 +105,9 @@ static ssize_t wait_for_direct_io(enum ORANGEFS_io_type type, struct inode *inod
 	ssize_t ret;
 
 	new_op = op_alloc(ORANGEFS_VFS_OP_FILE_IO);
-	if (!new_op) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (!new_op)
+		return -ENOMEM;
+
 	/* synchronous I/O */
 	new_op->upcall.req.io.async_vfs_io = ORANGEFS_VFS_SYNC_IO;
 	new_op->upcall.req.io.readahead_size = readahead_size;
@@ -234,12 +233,9 @@ populate_shared_memory:
 
 	/*
 	 * tell the device file owner waiting on I/O that this read has
-	 * completed and it can return now.  in this exact case, on
-	 * wakeup the daemon will free the op, so we *cannot* touch it
-	 * after this.
+	 * completed and it can return now.
 	 */
 	wake_up_daemon_for_return(new_op);
-	new_op = NULL;
 
 out:
 	if (buffer_index >= 0) {
@@ -249,10 +245,7 @@ out:
 			     __func__, handle, buffer_index);
 		buffer_index = -1;
 	}
-	if (new_op) {
-		op_release(new_op);
-		new_op = NULL;
-	}
+	op_release(new_op);
 	return ret;
 }