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Commit afd9d6a1 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Darrick J. Wong
Browse files

fs: use ->is_partially_uptodate in page_cache_seek_hole_data 



This way the implementation doesn't depend on buffer_head internals.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent bd56b3e1

fs/iomap.c

+40 −43
Original line number Diff line number Diff line
@@ -595,34 +595,53 @@ EXPORT_SYMBOL_GPL(iomap_fiemap); 


/*

 * Seek for SEEK_DATA / SEEK_HOLE within @page, starting at @lastoff.

 *

 * Returns the offset within the file on success, and -ENOENT otherwise.

 * Returns true if found and updates @lastoff to the offset in file.

 */

static loff_t

page_seek_hole_data(struct page *page, loff_t lastoff, int whence)

static bool

page_seek_hole_data(struct inode *inode, struct page *page, loff_t *lastoff,

		int whence)

{

	loff_t offset = page_offset(page);

	struct buffer_head *bh, *head;

	const struct address_space_operations *ops = inode->i_mapping->a_ops;

	unsigned int bsize = i_blocksize(inode), off;

	bool seek_data = whence == SEEK_DATA;

	loff_t poff = page_offset(page);



	if (lastoff < offset)

		lastoff = offset;

	if (WARN_ON_ONCE(*lastoff >= poff + PAGE_SIZE))

		return false;



	bh = head = page_buffers(page);

	do {

		offset += bh->b_size;

		if (lastoff >= offset)

			continue;

	if (*lastoff < poff) {

		/*

		 * Last offset smaller than the start of the page means we found

		 * a hole:

		 */

		if (whence == SEEK_HOLE)

			return true;

		*lastoff = poff;

	}



	/*

		 * Any buffer with valid data in it should have BH_Uptodate set.

	 * Just check the page unless we can and should check block ranges:

	 */

		if (buffer_uptodate(bh) == seek_data)

			return lastoff;

	if (bsize == PAGE_SIZE || !ops->is_partially_uptodate)

		return PageUptodate(page) == seek_data;



		lastoff = offset;

	} while ((bh = bh->b_this_page) != head);

	return -ENOENT;

	lock_page(page);

	if (unlikely(page->mapping != inode->i_mapping))

		goto out_unlock_not_found;



	for (off = 0; off < PAGE_SIZE; off += bsize) {

		if ((*lastoff & ~PAGE_MASK) >= off + bsize)

			continue;

		if (ops->is_partially_uptodate(page, off, bsize) == seek_data) {

			unlock_page(page);

			return true;

		}

		*lastoff = poff + off + bsize;

	}



out_unlock_not_found:

	unlock_page(page);

	return false;

}



/*
@@ -659,30 +678,8 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length, 
		for (i = 0; i < nr_pages; i++) {

			struct page *page = pvec.pages[i];



			/*

			 * At this point, the page may be truncated or

			 * invalidated (changing page->mapping to NULL), or

			 * even swizzled back from swapper_space to tmpfs file

			 * mapping.  However, page->index will not change

			 * because we have a reference on the page.

                         *

			 * If current page offset is beyond where we've ended,

			 * we've found a hole.

                         */

			if (whence == SEEK_HOLE &&

			    lastoff < page_offset(page))

				goto check_range;



			lock_page(page);

			if (likely(page->mapping == inode->i_mapping) &&

			    page_has_buffers(page)) {

				lastoff = page_seek_hole_data(page, lastoff, whence);

				if (lastoff >= 0) {

					unlock_page(page);

			if (page_seek_hole_data(inode, page, &lastoff, whence))

				goto check_range;

				}

			}

			unlock_page(page);

			lastoff = page_offset(page) + PAGE_SIZE;

		}

		pagevec_release(&pvec);