Commit df0db3ec authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Darrick J. Wong
Browse files

iomap: Add a page_prepare callback 



Move the page_done callback into a separate iomap_page_ops structure and
add a page_prepare calback to be called before the next page is written
to.  In gfs2, we'll want to start a transaction in page_prepare and end
it in page_done.  Other filesystems that implement data journaling will
require the same kind of mechanism.

Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent 7a77dad7

fs/gfs2/bmap.c

+10 −5
Original line number Diff line number Diff line
@@ -965,15 +965,20 @@ static void gfs2_write_unlock(struct inode *inode) 
	gfs2_glock_dq_uninit(&ip->i_gh);

}



static void gfs2_iomap_journaled_page_done(struct inode *inode, loff_t pos,

static void gfs2_iomap_page_done(struct inode *inode, loff_t pos,

				 unsigned copied, struct page *page,

				 struct iomap *iomap)

{

	struct gfs2_inode *ip = GFS2_I(inode);



	if (page)

		gfs2_page_add_databufs(ip, page, offset_in_page(pos), copied);

}



static const struct iomap_page_ops gfs2_iomap_page_ops = {

	.page_done = gfs2_iomap_page_done,

};



static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos,

				  loff_t length, unsigned flags,

				  struct iomap *iomap,
@@ -1051,7 +1056,7 @@ static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos, 
		}

	}

	if (!gfs2_is_stuffed(ip) && gfs2_is_jdata(ip))

		iomap->page_done = gfs2_iomap_journaled_page_done;

		iomap->page_ops = &gfs2_iomap_page_ops;

	return 0;



out_trans_end:

fs/iomap.c

+26 −10
Original line number Diff line number Diff line
@@ -657,6 +657,7 @@ static int 
iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,

		struct page **pagep, struct iomap *iomap)

{

	const struct iomap_page_ops *page_ops = iomap->page_ops;

	pgoff_t index = pos >> PAGE_SHIFT;

	struct page *page;

	int status = 0;
@@ -666,9 +667,17 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, 
	if (fatal_signal_pending(current))

		return -EINTR;



	if (page_ops && page_ops->page_prepare) {

		status = page_ops->page_prepare(inode, pos, len, iomap);

		if (status)

			return status;

	}



	page = grab_cache_page_write_begin(inode->i_mapping, index, flags);

	if (!page)

		return -ENOMEM;

	if (!page) {

		status = -ENOMEM;

		goto out_no_page;

	}



	if (iomap->type == IOMAP_INLINE)

		iomap_read_inline_data(inode, page, iomap);
@@ -676,15 +685,21 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, 
		status = __block_write_begin_int(page, pos, len, NULL, iomap);

	else

		status = __iomap_write_begin(inode, pos, len, page, iomap);

	if (unlikely(status)) {



	if (unlikely(status))

		goto out_unlock;



	*pagep = page;

	return 0;



out_unlock:

	unlock_page(page);

	put_page(page);

		page = NULL;



	iomap_write_failed(inode, pos, len);

	}



	*pagep = page;

out_no_page:

	if (page_ops && page_ops->page_done)

		page_ops->page_done(inode, pos, 0, NULL, iomap);

	return status;

}
@@ -758,6 +773,7 @@ static int 
iomap_write_end(struct inode *inode, loff_t pos, unsigned len,

		unsigned copied, struct page *page, struct iomap *iomap)

{

	const struct iomap_page_ops *page_ops = iomap->page_ops;

	int ret;



	if (iomap->type == IOMAP_INLINE) {
@@ -770,8 +786,8 @@ iomap_write_end(struct inode *inode, loff_t pos, unsigned len, 
	}



	__generic_write_end(inode, pos, ret, page);

	if (iomap->page_done)

		iomap->page_done(inode, pos, copied, page, iomap);

	if (page_ops && page_ops->page_done)

		page_ops->page_done(inode, pos, copied, page, iomap);

	put_page(page);



	if (ret < len)

include/linux/iomap.h

+17 −5
Original line number Diff line number Diff line
@@ -53,6 +53,8 @@ struct vm_fault; 
 */

#define IOMAP_NULL_ADDR -1ULL	/* addr is not valid */



struct iomap_page_ops;



struct iomap {

	u64			addr; /* disk offset of mapping, bytes */

	loff_t			offset;	/* file offset of mapping, bytes */
@@ -63,12 +65,22 @@ struct iomap { 
	struct dax_device	*dax_dev; /* dax_dev for dax operations */

	void			*inline_data;

	void			*private; /* filesystem private */

	const struct iomap_page_ops *page_ops;

};



/*

	 * Called when finished processing a page in the mapping returned in

	 * this iomap.  At least for now this is only supported in the buffered

	 * write path.

 * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare

 * and page_done will be called for each page written to.  This only applies to

 * buffered writes as unbuffered writes will not typically have pages

 * associated with them.

 *

 * When page_prepare succeeds, page_done will always be called to do any

 * cleanup work necessary.  In that page_done call, @page will be NULL if the

 * associated page could not be obtained.

 */

struct iomap_page_ops {

	int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len,

			struct iomap *iomap);

	void (*page_done)(struct inode *inode, loff_t pos, unsigned copied,

			struct page *page, struct iomap *iomap);

};

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