Commit 6d68f644 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

buffer: convert block_truncate_page() to use a folio 

Support large folios in block_truncate_page() and avoid three hidden calls
to compound_head().

[willy@infradead.org: fix check of filemap_grab_folio() return value]
  Link: https://lkml.kernel.org/r/ZItZOt+XxV12HtzL@casper.infradead.org
Link: https://lkml.kernel.org/r/20230612210141.730128-15-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent eee25182

fs/buffer.c

+16 −14
Original line number Diff line number Diff line
@@ -2598,17 +2598,16 @@ int block_truncate_page(struct address_space *mapping, 
			loff_t from, get_block_t *get_block)

{

	pgoff_t index = from >> PAGE_SHIFT;

	unsigned offset = from & (PAGE_SIZE-1);

	unsigned blocksize;

	sector_t iblock;

	unsigned length, pos;

	size_t offset, length, pos;

	struct inode *inode = mapping->host;

	struct page *page;

	struct folio *folio;

	struct buffer_head *bh;

	int err = 0;



	blocksize = i_blocksize(inode);

	length = offset & (blocksize - 1);

	length = from & (blocksize - 1);



	/* Block boundary? Nothing to do */

	if (!length)
@@ -2617,15 +2616,18 @@ int block_truncate_page(struct address_space *mapping, 
	length = blocksize - length;

	iblock = (sector_t)index << (PAGE_SHIFT - inode->i_blkbits);

	

	page = grab_cache_page(mapping, index);

	if (!page)

		return -ENOMEM;

	folio = filemap_grab_folio(mapping, index);

	if (IS_ERR(folio))

		return PTR_ERR(folio);



	if (!page_has_buffers(page))

		create_empty_buffers(page, blocksize, 0);

	bh = folio_buffers(folio);

	if (!bh) {

		folio_create_empty_buffers(folio, blocksize, 0);

		bh = folio_buffers(folio);

	}



	/* Find the buffer that contains "offset" */

	bh = page_buffers(page);

	offset = offset_in_folio(folio, from);

	pos = blocksize;

	while (offset >= pos) {

		bh = bh->b_this_page;
@@ -2644,7 +2646,7 @@ int block_truncate_page(struct address_space *mapping, 
	}



	/* Ok, it's mapped. Make sure it's up-to-date */

	if (PageUptodate(page))

	if (folio_test_uptodate(folio))

		set_buffer_uptodate(bh);



	if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) {
@@ -2654,12 +2656,12 @@ int block_truncate_page(struct address_space *mapping, 
			goto unlock;

	}



	zero_user(page, offset, length);

	folio_zero_range(folio, offset, length);

	mark_buffer_dirty(bh);



unlock:

	unlock_page(page);

	put_page(page);

	folio_unlock(folio);

	folio_put(folio);



	return err;

}