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Commit 5f4e5752 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dave Chinner
Browse files

fs: add iomap_file_dirty 



Originally-From: Christoph Hellwig <hch@lst.de>

This function uses the iomap infrastructure to re-write all pages
in a given range.  This is useful for doing a copy-up of COW ranges,
and might be useful for scrubbing in the future.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent ea78d808

fs/iomap.c

+82 −0
Original line number Diff line number Diff line
@@ -252,6 +252,88 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter, 
}

EXPORT_SYMBOL_GPL(iomap_file_buffered_write);



static struct page *

__iomap_read_page(struct inode *inode, loff_t offset)

{

	struct address_space *mapping = inode->i_mapping;

	struct page *page;



	page = read_mapping_page(mapping, offset >> PAGE_SHIFT, NULL);

	if (IS_ERR(page))

		return page;

	if (!PageUptodate(page)) {

		put_page(page);

		return ERR_PTR(-EIO);

	}

	return page;

}



static loff_t

iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data,

		struct iomap *iomap)

{

	long status = 0;

	ssize_t written = 0;



	do {

		struct page *page, *rpage;

		unsigned long offset;	/* Offset into pagecache page */

		unsigned long bytes;	/* Bytes to write to page */



		offset = (pos & (PAGE_SIZE - 1));

		bytes = min_t(unsigned long, PAGE_SIZE - offset, length);



		rpage = __iomap_read_page(inode, pos);

		if (IS_ERR(rpage))

			return PTR_ERR(rpage);



		status = iomap_write_begin(inode, pos, bytes,

				AOP_FLAG_NOFS | AOP_FLAG_UNINTERRUPTIBLE,

				&page, iomap);

		put_page(rpage);

		if (unlikely(status))

			return status;



		WARN_ON_ONCE(!PageUptodate(page));



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

		if (unlikely(status <= 0)) {

			if (WARN_ON_ONCE(status == 0))

				return -EIO;

			return status;

		}



		cond_resched();



		pos += status;

		written += status;

		length -= status;



		balance_dirty_pages_ratelimited(inode->i_mapping);

	} while (length);



	return written;

}



int

iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,

		struct iomap_ops *ops)

{

	loff_t ret;



	while (len) {

		ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops, NULL,

				iomap_dirty_actor);

		if (ret <= 0)

			return ret;

		pos += ret;

		len -= ret;

	}



	return 0;

}

EXPORT_SYMBOL_GPL(iomap_file_dirty);



static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset,

		unsigned bytes, struct iomap *iomap)

{

include/linux/iomap.h

+2 −0
Original line number Diff line number Diff line
@@ -64,6 +64,8 @@ struct iomap_ops { 


ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,

		struct iomap_ops *ops);

int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,

		struct iomap_ops *ops);

int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,

		bool *did_zero, struct iomap_ops *ops);

int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,