Commit 382497ad authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

buffer: calculate block number inside folio_init_buffers() 

The calculation of block from index doesn't work for devices with a block
size larger than PAGE_SIZE as we end up shifting by a negative number. 
Instead, calculate the number of the first block from the folio's position
in the block device.  We no longer need to pass sizebits to
grow_dev_folio().

Link: https://lkml.kernel.org/r/20231109210608.2252323-3-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 6d840a18

fs/buffer.c

+6 −7
Original line number Diff line number Diff line
@@ -995,11 +995,12 @@ static sector_t blkdev_max_block(struct block_device *bdev, unsigned int size) 
 * Initialise the state of a blockdev folio's buffers.

 */ 

static sector_t folio_init_buffers(struct folio *folio,

		struct block_device *bdev, sector_t block, int size)

		struct block_device *bdev, unsigned size)

{

	struct buffer_head *head = folio_buffers(folio);

	struct buffer_head *bh = head;

	bool uptodate = folio_test_uptodate(folio);

	sector_t block = div_u64(folio_pos(folio), size);

	sector_t end_block = blkdev_max_block(bdev, size);



	do {
@@ -1032,7 +1033,7 @@ static sector_t folio_init_buffers(struct folio *folio, 
 * we succeeded, or the caller should retry.

 */

static bool grow_dev_folio(struct block_device *bdev, sector_t block,

		pgoff_t index, unsigned size, int sizebits, gfp_t gfp)

		pgoff_t index, unsigned size, gfp_t gfp)

{

	struct inode *inode = bdev->bd_inode;

	struct folio *folio;
@@ -1047,8 +1048,7 @@ static bool grow_dev_folio(struct block_device *bdev, sector_t block, 
	bh = folio_buffers(folio);

	if (bh) {

		if (bh->b_size == size) {

			end_block = folio_init_buffers(folio, bdev,

					(sector_t)index << sizebits, size);

			end_block = folio_init_buffers(folio, bdev, size);

			goto unlock;

		}
@@ -1069,8 +1069,7 @@ static bool grow_dev_folio(struct block_device *bdev, sector_t block, 
	 */

	spin_lock(&inode->i_mapping->private_lock);

	link_dev_buffers(folio, bh);

	end_block = folio_init_buffers(folio, bdev,

			(sector_t)index << sizebits, size);

	end_block = folio_init_buffers(folio, bdev, size);

	spin_unlock(&inode->i_mapping->private_lock);

unlock:

	folio_unlock(folio);
@@ -1105,7 +1104,7 @@ static bool grow_buffers(struct block_device *bdev, sector_t block, 
	}



	/* Create a folio with the proper size buffers */

	return grow_dev_folio(bdev, block, index, size, sizebits, gfp);

	return grow_dev_folio(bdev, block, index, size, gfp);

}



static struct buffer_head *