From: Dave Chinner <david@fromorbit.com>
To: Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc: linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org,
hch@lst.de, darrick.wong@oracle.com, ruansy.fnst@cn.fujitsu.com,
Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: Re: [PATCH 01/13] iomap: Use a IOMAP_COW/srcmap for a read-modify-write I/O
Date: Mon, 5 Aug 2019 10:06:46 +1000 [thread overview]
Message-ID: <20190805000646.GE7689@dread.disaster.area> (raw)
In-Reply-To: <20190802220048.16142-2-rgoldwyn@suse.de>
On Fri, Aug 02, 2019 at 05:00:36PM -0500, Goldwyn Rodrigues wrote:
> From: Goldwyn Rodrigues <rgoldwyn@suse.com>
>
> Introduces a new type IOMAP_COW, which means the data at offset
> must be read from a srcmap and copied before performing the
> write on the offset.
>
> The srcmap is used to identify where the read is to be performed
> from. This is passed to iomap->begin() of the respective
> filesystem, which is supposed to put in the details for
> reading before performing the copy for CoW.
>
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
> ---
> fs/dax.c | 8 +++++---
> fs/ext2/inode.c | 2 +-
> fs/ext4/inode.c | 2 +-
> fs/gfs2/bmap.c | 3 ++-
> fs/iomap/apply.c | 5 +++--
> fs/iomap/buffered-io.c | 14 +++++++-------
> fs/iomap/direct-io.c | 2 +-
> fs/iomap/fiemap.c | 4 ++--
> fs/iomap/seek.c | 4 ++--
> fs/iomap/swapfile.c | 3 ++-
> fs/xfs/xfs_iomap.c | 9 ++++++---
> include/linux/iomap.h | 6 ++++--
> 12 files changed, 36 insertions(+), 26 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index a237141d8787..b21d9a9cde2b 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -1090,7 +1090,7 @@ EXPORT_SYMBOL_GPL(__dax_zero_page_range);
>
> static loff_t
> dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
> - struct iomap *iomap)
> + struct iomap *iomap, struct iomap *srcmap)
> {
> struct block_device *bdev = iomap->bdev;
> struct dax_device *dax_dev = iomap->dax_dev;
> @@ -1248,6 +1248,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
> unsigned long vaddr = vmf->address;
> loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT;
> struct iomap iomap = { 0 };
> + struct iomap srcmap = { 0 };
I'm not found of defining multiple iomaps everywhere and passing
them explicitly to every function that might need them. Perhaps
something like:
DEFINE_IOMAP(iomap);
#define IOMAP_BASE_MAP 0
#define IOMAP_SOURCE_MAP 1
#define IOMAP_MAX_MAPS 2
#define DEFINE_IOMAP(name) \
(struct iomap #name[IOMAP_MAX_MAPS] = {{0}})
#define IOMAP_B(name) ((name)[IOMAP_BASE_MAP])
#define IOMAP_S(name) ((name)[IOMAP_SOURCE_MAP])
And now we only have to pass a single iomap parameter to each
function as "struct iomap **iomap". This makes the code somewhat
simpler, and we only ever need to use IOMAP_S(iomap) when
IOMAP_B(iomap)->type == IOMAP_COW.
The other advantage of this is that if we even need new
functionality that requires 2 (or more) iomaps, we don't have to
change APIs again....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2019-08-05 0:23 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-02 22:00 [PATCH v2 0/13] Btrfs iomap Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 01/13] iomap: Use a IOMAP_COW/srcmap for a read-modify-write I/O Goldwyn Rodrigues
2019-08-03 0:39 ` Darrick J. Wong
2019-08-05 0:06 ` Dave Chinner [this message]
2019-08-02 22:00 ` [PATCH 02/13] iomap: Read page from srcmap for IOMAP_COW Goldwyn Rodrigues
2019-08-03 0:23 ` Darrick J. Wong
2019-08-04 23:52 ` Dave Chinner
2019-08-02 22:00 ` [PATCH 03/13] btrfs: Eliminate PagePrivate for btrfs data pages Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 04/13] btrfs: Add a simple buffered iomap write Goldwyn Rodrigues
2019-08-05 0:11 ` Dave Chinner
2019-08-22 15:05 ` Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 05/13] btrfs: Add CoW in iomap based writes Goldwyn Rodrigues
2019-08-05 0:13 ` Dave Chinner
2019-08-22 15:01 ` Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 06/13] btrfs: remove buffered write code made unnecessary Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 07/13] btrfs: basic direct read operation Goldwyn Rodrigues
2019-08-12 12:32 ` RITESH HARJANI
2019-08-22 15:00 ` Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 08/13] btrfs: Carve out btrfs_get_extent_map_write() out of btrfs_get_blocks_write() Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 09/13] btrfs: Rename __endio_write_update_ordered() to btrfs_update_ordered_extent() Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 10/13] iomap: use a function pointer for dio submits Goldwyn Rodrigues
2019-08-03 0:21 ` Darrick J. Wong
2019-08-05 16:08 ` Goldwyn Rodrigues
2019-08-04 23:43 ` Dave Chinner
2019-08-05 16:08 ` Goldwyn Rodrigues
2019-08-05 21:54 ` Dave Chinner
2019-08-08 4:26 ` Gao Xiang
2019-08-08 4:52 ` Gao Xiang
2019-08-08 5:49 ` Eric Biggers
2019-08-08 6:28 ` Gao Xiang
2019-08-08 8:16 ` Dave Chinner
2019-08-08 8:57 ` Gao Xiang
2019-08-08 9:29 ` Gao Xiang
2019-08-08 11:21 ` Gao Xiang
2019-08-08 13:11 ` Gao Xiang
2019-08-09 20:45 ` Matthew Wilcox
2019-08-09 23:45 ` Gao Xiang
2019-08-10 0:31 ` Eric Biggers
2019-08-10 0:50 ` Eric Biggers
2019-08-10 1:34 ` Gao Xiang
2019-08-10 1:13 ` Gao Xiang
2019-08-10 0:17 ` Eric Biggers
2019-08-02 22:00 ` [PATCH 11/13] btrfs: Use iomap_dio_rw for performing direct I/O writes Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 12/13] btrfs: Remove btrfs_dio_data and __btrfs_direct_write Goldwyn Rodrigues
2019-08-02 22:00 ` [PATCH 13/13] btrfs: update inode size during bio completion Goldwyn Rodrigues
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=20190805000646.GE7689@dread.disaster.area \
--to=david@fromorbit.com \
--cc=darrick.wong@oracle.com \
--cc=hch@lst.de \
--cc=linux-btrfs@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=rgoldwyn@suse.com \
--cc=rgoldwyn@suse.de \
--cc=ruansy.fnst@cn.fujitsu.com \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).