* [patch] ext4: clean up the flags passed to __blockdev_direct_IO for extent-based files
@ 2012-02-24 21:49 Jeff Moyer
2012-02-24 21:52 ` Eric Sandeen
2012-03-05 15:25 ` Ted Ts'o
0 siblings, 2 replies; 3+ messages in thread
From: Jeff Moyer @ 2012-02-24 21:49 UTC (permalink / raw)
To: linux-ext4
Hi,
For extent-based files, you can perform DIO to holes, as mentioned in
the comments in ext4_ext_direct_IO. However, that function passes
DIO_SKIP_HOLES to __blockdev_direct_IO, which is *really* confusing to
the uninitiated reader. The key, here, is that the get_block function
passed in, ext4_get_block_write, completely ignores the create flag that
is passed to it (the create flag is passed in from the direct I/O code,
which uses the DIO_SKIP_HOLES flag to determine whether or not it should
be cleared).
This is a long-winded way of saying that the DIO_SKIP_HOLES flag is
ultimately ignored. So, in the interest of preserving sanity, I propose
the following patch.
Cheers,
Jeff
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index feaa82f..521ca03 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2940,7 +2940,7 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
ext4_get_block_write,
ext4_end_io_dio,
NULL,
- DIO_LOCKING | DIO_SKIP_HOLES);
+ DIO_LOCKING);
if (iocb->private)
EXT4_I(inode)->cur_aio_dio = NULL;
/*
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [patch] ext4: clean up the flags passed to __blockdev_direct_IO for extent-based files
2012-02-24 21:49 [patch] ext4: clean up the flags passed to __blockdev_direct_IO for extent-based files Jeff Moyer
@ 2012-02-24 21:52 ` Eric Sandeen
2012-03-05 15:25 ` Ted Ts'o
1 sibling, 0 replies; 3+ messages in thread
From: Eric Sandeen @ 2012-02-24 21:52 UTC (permalink / raw)
To: Jeff Moyer; +Cc: linux-ext4
On 2/24/12 3:49 PM, Jeff Moyer wrote:
> Hi,
>
> For extent-based files, you can perform DIO to holes, as mentioned in
> the comments in ext4_ext_direct_IO. However, that function passes
> DIO_SKIP_HOLES to __blockdev_direct_IO, which is *really* confusing to
> the uninitiated reader. The key, here, is that the get_block function
> passed in, ext4_get_block_write, completely ignores the create flag that
> is passed to it (the create flag is passed in from the direct I/O code,
> which uses the DIO_SKIP_HOLES flag to determine whether or not it should
> be cleared).
>
> This is a long-winded way of saying that the DIO_SKIP_HOLES flag is
> ultimately ignored. So, in the interest of preserving sanity, I propose
> the following patch.
>
> Cheers,
> Jeff
>
> Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Thank you sir.
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index feaa82f..521ca03 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -2940,7 +2940,7 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
> ext4_get_block_write,
> ext4_end_io_dio,
> NULL,
> - DIO_LOCKING | DIO_SKIP_HOLES);
> + DIO_LOCKING);
> if (iocb->private)
> EXT4_I(inode)->cur_aio_dio = NULL;
> /*
> --
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [patch] ext4: clean up the flags passed to __blockdev_direct_IO for extent-based files
2012-02-24 21:49 [patch] ext4: clean up the flags passed to __blockdev_direct_IO for extent-based files Jeff Moyer
2012-02-24 21:52 ` Eric Sandeen
@ 2012-03-05 15:25 ` Ted Ts'o
1 sibling, 0 replies; 3+ messages in thread
From: Ted Ts'o @ 2012-03-05 15:25 UTC (permalink / raw)
To: Jeff Moyer; +Cc: linux-ext4
On Fri, Feb 24, 2012 at 04:49:21PM -0500, Jeff Moyer wrote:
> Hi,
>
> For extent-based files, you can perform DIO to holes, as mentioned in
> the comments in ext4_ext_direct_IO. However, that function passes
> DIO_SKIP_HOLES to __blockdev_direct_IO, which is *really* confusing to
> the uninitiated reader. The key, here, is that the get_block function
> passed in, ext4_get_block_write, completely ignores the create flag that
> is passed to it (the create flag is passed in from the direct I/O code,
> which uses the DIO_SKIP_HOLES flag to determine whether or not it should
> be cleared).
>
> This is a long-winded way of saying that the DIO_SKIP_HOLES flag is
> ultimately ignored. So, in the interest of preserving sanity, I propose
> the following patch.
>
> Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Thanks, applied.
- Ted
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2012-03-05 15:25 UTC | newest]
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2012-02-24 21:49 [patch] ext4: clean up the flags passed to __blockdev_direct_IO for extent-based files Jeff Moyer
2012-02-24 21:52 ` Eric Sandeen
2012-03-05 15:25 ` Ted Ts'o
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