All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org,
	linux-block@vger.kernel.org
Subject: Re: [PATCH 05/12] fs: add a F_IOINFO fcntl
Date: Tue, 28 Feb 2017 08:51:39 -0800	[thread overview]
Message-ID: <20170228165139.GI5297@birch.djwong.org> (raw)
In-Reply-To: <20170228145737.19016-6-hch@lst.de>

On Tue, Feb 28, 2017 at 06:57:30AM -0800, Christoph Hellwig wrote:
> This fcntl can be used to query I/O parameters for the given file
> descriptor.  Initially it is used for the I/O alignment and atomic
> write parameters.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/fcntl.c                 | 18 ++++++++++++++++++
>  include/linux/fs.h         |  1 +
>  include/uapi/linux/fcntl.h | 16 ++++++++++++++++
>  3 files changed, 35 insertions(+)
> 
> diff --git a/fs/fcntl.c b/fs/fcntl.c
> index ca5d228be7ea..248fb4cc66a6 100644
> --- a/fs/fcntl.c
> +++ b/fs/fcntl.c
> @@ -241,6 +241,21 @@ static int f_getowner_uids(struct file *filp, unsigned long arg)
>  }
>  #endif
>  
> +static int fcntl_ioinfo(struct file *file, void __user *argp)
> +{
> +	struct fcntl_ioinfo fio = { 0, };
> +
> +	if (file->f_op->ioinfo) {
> +		int ret = file->f_op->ioinfo(file, &fio);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	if (copy_to_user(argp, &fio, sizeof(fio)))
> +		return -EFAULT;
> +	return 0;
> +}
> +
>  static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
>  		struct file *filp)
>  {
> @@ -335,6 +350,9 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
>  	case F_GET_SEALS:
>  		err = shmem_fcntl(filp, cmd, arg);
>  		break;
> +	case F_IOINFO:
> +		err = fcntl_ioinfo(filp, (void __user *)arg);
> +		break;
>  	default:
>  		break;
>  	}
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 2ba074328894..33b08a8c2bc3 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1680,6 +1680,7 @@ struct file_operations {
>  			u64);
>  	ssize_t (*dedupe_file_range)(struct file *, u64, u64, struct file *,
>  			u64);
> +	int (*ioinfo)(struct file *, struct fcntl_ioinfo *);
>  };
>  
>  struct inode_operations {
> diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h
> index beed138bd359..6b0aaba7c623 100644
> --- a/include/uapi/linux/fcntl.h
> +++ b/include/uapi/linux/fcntl.h
> @@ -42,6 +42,22 @@
>  #define F_SEAL_WRITE	0x0008	/* prevent writes */
>  /* (1U << 31) is reserved for signed error codes */
>  
> +
> +#define F_IOINFO	(F_LINUX_SPECIFIC_BASE +  11)
> +
> +struct fcntl_ioinfo {
> +	__u16		fio_flags;	/* FIO_FL_* */
> +	__u16		fio_alignment;	/* required I/O alignment on disk */

Hm... is fio_alignment is specified in units of bytes?  If so, then
shouldn't this be a __u32 so that we can handle some weird future device
that wants, say, 1MB alignment for its atomic IO?

I'm not sure there /are/ such weird devices, and the current patchset
assumes (probably sanely) that atomic requests only have to be
lba-aligned, but otoh this is a userland field and we have plenty of
reserved space.

Though, now that I look at the XFS ioinfo patch, I guess fio_alignment
is set only for O_DIRECT files?  So it's really the required alignment
for directio operations.

(Now I think I'm simply confused about this field.)

--D

> +	__u32		__reserved1;	/* must be zero */
> +	__u64		fio_max_atomic;	/* max size for atomic writes */
> +	__u64		__reserved2[14];/* must be zero */
> +};
> +
> +/* supports atomic writes using O_(D)SYNC */
> +#define FIO_FL_ATOMIC_OSYNC	(1 << 0)
> +/* supports atomic writes committed using fsync/fdatasync/msync */
> +#define FIO_FL_ATOMIC_FSYNC	(1 << 1)
> +
>  /*
>   * Types of directory notifications that may be requested.
>   */
> -- 
> 2.11.0
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

  reply	other threads:[~2017-02-28 16:51 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-28 14:57 [RFC] failure atomic writes for file systems and block devices Christoph Hellwig
2017-02-28 14:57 ` [PATCH 01/12] uapi/fs: add O_ATOMIC to the open flags Christoph Hellwig
2017-02-28 14:57 ` [PATCH 02/12] iomap: pass IOMAP_* flags to actors Christoph Hellwig
2017-02-28 14:57 ` [PATCH 03/12] iomap: add a IOMAP_ATOMIC flag Christoph Hellwig
2017-02-28 14:57 ` [PATCH 04/12] fs: add a BH_Atomic flag Christoph Hellwig
2017-02-28 14:57 ` [PATCH 05/12] fs: add a F_IOINFO fcntl Christoph Hellwig
2017-02-28 16:51   ` Darrick J. Wong [this message]
2017-03-01 15:11     ` Christoph Hellwig
2017-02-28 14:57 ` [PATCH 06/12] xfs: cleanup is_reflink checks Christoph Hellwig
2017-02-28 14:57 ` [PATCH 07/12] xfs: implement failure-atomic writes Christoph Hellwig
2017-02-28 23:09   ` Darrick J. Wong
2017-03-01 15:17     ` Christoph Hellwig
2017-02-28 14:57 ` [PATCH 08/12] xfs: implement the F_IOINFO fcntl Christoph Hellwig
2017-02-28 14:57 ` [PATCH 09/12] block: advertize max atomic write limit Christoph Hellwig
2017-02-28 14:57 ` [PATCH 10/12] block_dev: set REQ_NOMERGE for O_ATOMIC writes Christoph Hellwig
2017-02-28 14:57 ` [PATCH 11/12] block_dev: implement the F_IOINFO fcntl Christoph Hellwig
2017-02-28 14:57 ` [PATCH 12/12] nvme: export the atomic write limit Christoph Hellwig
2017-02-28 20:48 ` [RFC] failure atomic writes for file systems and block devices Chris Mason
2017-02-28 20:48   ` Chris Mason
2017-03-01 15:07   ` Christoph Hellwig
2017-02-28 23:22 ` Darrick J. Wong
2017-03-01 15:09   ` Christoph Hellwig
2017-03-01 11:21 ` Amir Goldstein
2017-03-01 15:07   ` Christoph Hellwig
2017-03-01 15:07     ` Christoph Hellwig

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20170228165139.GI5297@birch.djwong.org \
    --to=darrick.wong@oracle.com \
    --cc=hch@lst.de \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-xfs@vger.kernel.org \
    --subject='Re: [PATCH 05/12] fs: add a F_IOINFO fcntl' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.