Commit 4b04646c authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

buffer: fix various functions for block size > PAGE_SIZE 

If i_blkbits is larger than PAGE_SHIFT, we shift by a negative number,
which is undefined.  It is safe to shift the block left as a block device
must be smaller than MAX_LFS_FILESIZE, which is guaranteed to fit in
loff_t.

Link: https://lkml.kernel.org/r/20231109210608.2252323-6-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarPankaj Raghav <p.raghav@samsung.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 80844194

fs/buffer.c

+5 −5
Original line number Diff line number Diff line
@@ -199,7 +199,7 @@ __find_get_block_slow(struct block_device *bdev, sector_t block) 
	int all_mapped = 1;

	static DEFINE_RATELIMIT_STATE(last_warned, HZ, 1);



	index = block >> (PAGE_SHIFT - bd_inode->i_blkbits);

	index = ((loff_t)block << bd_inode->i_blkbits) / PAGE_SIZE;

	folio = __filemap_get_folio(bd_mapping, index, FGP_ACCESSED, 0);

	if (IS_ERR(folio))

		goto out;
@@ -1693,13 +1693,13 @@ void clean_bdev_aliases(struct block_device *bdev, sector_t block, sector_t len) 
	struct inode *bd_inode = bdev->bd_inode;

	struct address_space *bd_mapping = bd_inode->i_mapping;

	struct folio_batch fbatch;

	pgoff_t index = block >> (PAGE_SHIFT - bd_inode->i_blkbits);

	pgoff_t index = ((loff_t)block << bd_inode->i_blkbits) / PAGE_SIZE;

	pgoff_t end;

	int i, count;

	struct buffer_head *bh;

	struct buffer_head *head;



	end = (block + len - 1) >> (PAGE_SHIFT - bd_inode->i_blkbits);

	end = ((loff_t)(block + len - 1) << bd_inode->i_blkbits) / PAGE_SIZE;

	folio_batch_init(&fbatch);

	while (filemap_get_folios(bd_mapping, &index, end, &fbatch)) {

		count = folio_batch_count(&fbatch);
@@ -2660,7 +2660,7 @@ int block_truncate_page(struct address_space *mapping, 
		return 0;



	length = blocksize - length;

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

	iblock = ((loff_t)index * PAGE_SIZE) >> inode->i_blkbits;



	folio = filemap_grab_folio(mapping, index);

	if (IS_ERR(folio))