[patch] bug fix in dio handling write error

[Chen, Kenneth W]

There is a bug in direct-io on propagating write error up to the
higher I/O layer.  When performing an async ODIRECT write to a
block device, if a device error occurred (like media error or disk
is pulled), the error code is only propagated from device driver
to the DIO layer.  The error code stops at finished_one_bio(). The
aysnc write, however, is supposedly have a corresponding AIO event
with appropriate return code (in this case -EIO).  Application
which waits on the async write event, will hang forever since such
AIO event is lost forever (if such app did not use the timeout
option in io_getevents call. Regardless, an AIO event is lost).

The problem is that calls to aio_complete() is conditioned upon
READ, but it should've handle WRITE error as well.


Signed-off-by: Ken Chen <kenneth.w.chen@xxxxxxxxx>


--- linux-2.6.15/fs/direct-io.c.orig	2006-01-17 11:54:17.010422462 -0800
+++ linux-2.6.15/fs/direct-io.c	2006-01-17 12:08:00.444982688 -0800
@@ -253,8 +253,7 @@ static void finished_one_bio(struct dio 
 			dio_complete(dio, offset, transferred);
 
 			/* Complete AIO later if falling back to buffered i/o */
-			if (dio->result == dio->size ||
-				((dio->rw == READ) && dio->result)) {
+			if (dio->result == dio->size || dio->result) {
 				aio_complete(dio->iocb, transferred, 0);
 				kfree(dio);
 				return;



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