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: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Andreas Gruenbacher
2019-04-30 08:45:34 -07:00
committed by Darrick J. Wong
parent 7a77dad7e3
commit df0db3ecdb
3 changed files with 53 additions and 20 deletions

View File

@@ -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);
};