[2.6.18-rc* PATCH RFC]: Correct ambiguous errno of aio

[Yi Yang <yang.y.yi@gmail.com>]

In the current implementation of AIO, for the operation IOCB_CMD_FDSYNC
and IOCB_CMD_FSYNC, the returned errno is -EINVAL although the kernel
does know them, I think the correct errno should be -EOPNOTSUPP which
means they aren't be implemented or supported.

>From the kernel source code, we can see they can be supported without
any code modification if a specific filesystem implements aio_fsync.

Another obvious problem is the function aio_fsync is as same as the
function aio_fdsync, so they are duplicate, only one is enough.

Here this patch is.



--- a/fs/aio.c.orig 2006-08-28 15:15:18.000000000 +0800
+++ b/fs/aio.c 2006-08-28 15:33:59.000000000 +0800
@@ -1363,20 +1363,10 @@ static ssize_t aio_pwrite(struct kiocb *
return ret;
}

-static ssize_t aio_fdsync(struct kiocb *iocb)
-{
- struct file *file = iocb->ki_filp;
- ssize_t ret = -EINVAL;
-
- if (file->f_op->aio_fsync)
- ret = file->f_op->aio_fsync(iocb, 1);
- return ret;
-}
-
static ssize_t aio_fsync(struct kiocb *iocb)
{
struct file *file = iocb->ki_filp;
- ssize_t ret = -EINVAL;
+ ssize_t ret = -EOPNOTSUPP;

if (file->f_op->aio_fsync)
ret = file->f_op->aio_fsync(iocb, 0);
@@ -1425,12 +1415,12 @@ static ssize_t aio_setup_iocb(struct kio
kiocb->ki_retry = aio_pwrite;
break;
case IOCB_CMD_FDSYNC:
- ret = -EINVAL;
+ ret = -EOPNOTSUPP;
if (file->f_op->aio_fsync)
- kiocb->ki_retry = aio_fdsync;
+ kiocb->ki_retry = aio_fsync;
break;
case IOCB_CMD_FSYNC:
- ret = -EINVAL;
+ ret = -EOPNOTSUPP;
if (file->f_op->aio_fsync)
kiocb->ki_retry = aio_fsync;
break;