Unverified Commit 86c60efd authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Christian Brauner
Browse files

fs/mpage: avoid negative shift for large blocksize 



For large blocksizes the number of block bits is larger than PAGE_SHIFT,
so calculate the sector number from the byte offset instead. This is
required to enable large folios with buffer-heads.

Reviewed-by: default avatar"Matthew Wilcox (Oracle)" <willy@infradead.org>
Signed-off-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
Signed-off-by: default avatarHannes Reinecke <hare@kernel.org>
Link: https://lore.kernel.org/r/20250221223823.1680616-4-mcgrof@kernel.org


Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent b72e591f

fs/mpage.c

+2 −2
Original line number Diff line number Diff line
@@ -181,7 +181,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args) 
	if (folio_buffers(folio))

		goto confused;



	block_in_file = (sector_t)folio->index << (PAGE_SHIFT - blkbits);

	block_in_file = folio_pos(folio) >> blkbits;

	last_block = block_in_file + args->nr_pages * blocks_per_page;

	last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;

	if (last_block > last_block_in_file)
@@ -527,7 +527,7 @@ static int __mpage_writepage(struct folio *folio, struct writeback_control *wbc, 
	 * The page has no buffers: map it to disk

	 */

	BUG_ON(!folio_test_uptodate(folio));

	block_in_file = (sector_t)folio->index << (PAGE_SHIFT - blkbits);

	block_in_file = folio_pos(folio) >> blkbits;

	/*

	 * Whole page beyond EOF? Skip allocating blocks to avoid leaking

	 * space.