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Commit f892760a authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
Browse files

fs/mpage.c: fix mpage_writepage() for pages with buffers 

When using FAT on a block device which supports rw_page, we can hit
BUG_ON(!PageLocked(page)) in try_to_free_buffers().  This is because we
call clean_buffers() after unlocking the page we've written.  Introduce
a new clean_page_buffers() which cleans all buffers associated with a
page and call it from within bdev_write_page().

[akpm@linux-foundation.org: s/PAGE_SIZE/~0U/ per Linus and Matthew]
Link: http://lkml.kernel.org/r/20171006211541.GA7409@bombadil.infradead.org


Signed-off-by: default avatarMatthew Wilcox <mawilcox@microsoft.com>
Reported-by: default avatarToshi Kani <toshi.kani@hpe.com>
Reported-by: default avatarOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Tested-by: default avatarToshi Kani <toshi.kani@hpe.com>
Acked-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e8c97af0

fs/block_dev.c

+4 −2
Original line number Diff line number Diff line
@@ -716,10 +716,12 @@ int bdev_write_page(struct block_device *bdev, sector_t sector, 


	set_page_writeback(page);

	result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, true);

	if (result)

	if (result) {

		end_page_writeback(page);

	else

	} else {

		clean_page_buffers(page);

		unlock_page(page);

	}

	blk_queue_exit(bdev->bd_queue);

	return result;

}

fs/mpage.c

+11 −3
Original line number Diff line number Diff line
@@ -468,6 +468,16 @@ static void clean_buffers(struct page *page, unsigned first_unmapped) 
		try_to_free_buffers(page);

}



/*

 * For situations where we want to clean all buffers attached to a page.

 * We don't need to calculate how many buffers are attached to the page,

 * we just need to specify a number larger than the maximum number of buffers.

 */

void clean_page_buffers(struct page *page)

{

	clean_buffers(page, ~0U);

}



static int __mpage_writepage(struct page *page, struct writeback_control *wbc,

		      void *data)

{
@@ -605,11 +615,9 @@ static int __mpage_writepage(struct page *page, struct writeback_control *wbc, 
	if (bio == NULL) {

		if (first_unmapped == blocks_per_page) {

			if (!bdev_write_page(bdev, blocks[0] << (blkbits - 9),

								page, wbc)) {

				clean_buffers(page, first_unmapped);

								page, wbc))

				goto out;

		}

		}

		bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),

				BIO_MAX_PAGES, GFP_NOFS|__GFP_HIGH);

		if (bio == NULL)

include/linux/buffer_head.h

+1 −0
Original line number Diff line number Diff line
@@ -232,6 +232,7 @@ int generic_write_end(struct file *, struct address_space *, 
				loff_t, unsigned, unsigned,

				struct page *, void *);

void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);

void clean_page_buffers(struct page *page);

int cont_write_begin(struct file *, struct address_space *, loff_t,

			unsigned, unsigned, struct page **, void **,

			get_block_t *, loff_t *);