Commit 19e0c58f authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Darrick J. Wong
Browse files

iomap: generic inline data handling 



Add generic inline data handling by adding a pointer to the inline data
region to struct iomap.  When handling a buffered IOMAP_INLINE write,
iomap_write_begin will copy the current inline data from the inline data
region into the page cache, and iomap_write_end will copy the changes in
the page cache back to the inline data region.

This doesn't cover inline data reads and direct I/O yet because so far,
we have no users.

Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
[hch: small cleanups to better fit in with other iomap work]
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent ebf00be3

fs/iomap.c

+55 −7
Original line number Diff line number Diff line
@@ -103,6 +103,26 @@ iomap_sector(struct iomap *iomap, loff_t pos) 
	return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;

}



static void

iomap_read_inline_data(struct inode *inode, struct page *page,

		struct iomap *iomap)

{

	size_t size = i_size_read(inode);

	void *addr;



	if (PageUptodate(page))

		return;



	BUG_ON(page->index);

	BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data));



	addr = kmap_atomic(page);

	memcpy(addr, iomap->inline_data, size);

	memset(addr + size, 0, PAGE_SIZE - size);

	kunmap_atomic(addr);

	SetPageUptodate(page);

}



static void

iomap_write_failed(struct inode *inode, loff_t pos, unsigned len)

{
@@ -133,7 +153,11 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, 
	if (!page)

		return -ENOMEM;



	if (iomap->type == IOMAP_INLINE)

		iomap_read_inline_data(inode, page, iomap);

	else

		status = __block_write_begin_int(page, pos, len, NULL, iomap);



	if (unlikely(status)) {

		unlock_page(page);

		put_page(page);
@@ -146,14 +170,37 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, 
	return status;

}



static int

iomap_write_end_inline(struct inode *inode, struct page *page,

		struct iomap *iomap, loff_t pos, unsigned copied)

{

	void *addr;



	WARN_ON_ONCE(!PageUptodate(page));

	BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data));



	addr = kmap_atomic(page);

	memcpy(iomap->inline_data + pos, addr + pos, copied);

	kunmap_atomic(addr);



	mark_inode_dirty(inode);

	__generic_write_end(inode, pos, copied, page);

	return copied;

}



static int

iomap_write_end(struct inode *inode, loff_t pos, unsigned len,

		unsigned copied, struct page *page)

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

{

	int ret;



	if (iomap->type == IOMAP_INLINE) {

		ret = iomap_write_end_inline(inode, page, iomap, pos, copied);

	} else {

		ret = generic_write_end(NULL, inode->i_mapping, pos, len,

				copied, page, NULL);

	}



	if (ret < len)

		iomap_write_failed(inode, pos, len);

	return ret;
@@ -208,7 +255,8 @@ again: 


		flush_dcache_page(page);



		status = iomap_write_end(inode, pos, bytes, copied, page);

		status = iomap_write_end(inode, pos, bytes, copied, page,

				iomap);

		if (unlikely(status < 0))

			break;

		copied = status;
@@ -302,7 +350,7 @@ iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data, 


		WARN_ON_ONCE(!PageUptodate(page));



		status = iomap_write_end(inode, pos, bytes, bytes, page);

		status = iomap_write_end(inode, pos, bytes, bytes, page, iomap);

		if (unlikely(status <= 0)) {

			if (WARN_ON_ONCE(status == 0))

				return -EIO;
@@ -354,7 +402,7 @@ static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, 
	zero_user(page, offset, bytes);

	mark_page_accessed(page);



	return iomap_write_end(inode, pos, bytes, bytes, page);

	return iomap_write_end(inode, pos, bytes, bytes, page, iomap);

}



static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes,

include/linux/iomap.h

+1 −0
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ struct iomap { 
	u16			flags;	/* flags for mapping */

	struct block_device	*bdev;	/* block device for I/O */

	struct dax_device	*dax_dev; /* dax_dev for dax operations */

	void			*inline_data;

};



/*

CRA Git | Maintained and supported by SUSTech CRA and CCSE