Add support for offline files support, remote storage, and Async I/O force operations to VFS

Offline files support and remote storage are for allowing communication with
backup and archiving tools that mark files moved to a tape library as offline.
We translate this info into corresponding CIFS offline file attribute and
mark an exported volume as remote storage.

Async I/O force is to allow selective redirection of I/O operations to asynchronous
processing in case it is viable at VFS module discretion. It is needed for
proper handling of offline files as performing regular I/O on offline file will
block smbd.


Signed-off-by: Alexander Bokovoy <ab@samba.org>

1 files changed, 13 insertions, 6 deletions

diff --git a/source/smbd/reply.c b/source/smbd/reply.c
index e2316ef1200..381ddfe1517 100644
--- a/source/smbd/reply.c
+++ b/source/smbd/reply.c
@@ -3329,8 +3329,12 @@ void reply_read_and_X(struct smb_request *req)
 		return;
 	}
 
-	if (!big_readX
-	    && schedule_aio_read_and_X(conn, req, fsp, startpos, smb_maxcnt)) {
+	/* It is possible for VFS modules to selectively decide whether Async I/O should be used
+	   for the file or not.
+        */
+	if ((SMB_VFS_AIO_FORCE(fsp)) &&
+	    !big_readX &&
+	    schedule_aio_read_and_X(conn, req, fsp, startpos, smb_maxcnt)) {
 		END_PROFILE(SMBreadX);
 		return;
 	}
@@ -4001,13 +4005,16 @@ void reply_write_and_X(struct smb_request *req)
 		nwritten = 0;
 	} else {
 
-		if (req->unread_bytes == 0 &&
-				schedule_aio_write_and_X(conn, req, fsp, data,
-							startpos, numtowrite)) {
+		/* It is possible for VFS modules to selectively decide whether Async I/O
+		   should be used for the file or not.
+		*/
+		if ((SMB_VFS_AIO_FORCE(fsp)) && (req->unread_bytes == 0) &&
+		    schedule_aio_write_and_X(conn, req, fsp, data, startpos,
+					     numtowrite)) {
 			END_PROFILE(SMBwriteX);
 			return;
 		}
-
+		
 		nwritten = write_file(req,fsp,data,startpos,numtowrite);
 	}