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Commit 4aa83b7b authored by Lars Ellenberg's avatar Lars Ellenberg Committed by Philipp Reisner
Browse files

drbd: fix NULL pointer dereference on 4k hard sect size 



we still don't support 4k 'physical' sectors 'natively',
but use a read-modify-write workaround.
And we even tried to use the extra page before we allocated it :(

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent cf14c2e9

drivers/block/drbd/drbd_nl.c

+19 −19
Original line number Diff line number Diff line
@@ -941,6 +941,25 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp 


	drbd_md_set_sector_offsets(mdev, nbc);



	/* allocate a second IO page if logical_block_size != 512 */

	logical_block_size = bdev_logical_block_size(nbc->md_bdev);

	if (logical_block_size == 0)

		logical_block_size = MD_SECTOR_SIZE;



	if (logical_block_size != MD_SECTOR_SIZE) {

		if (!mdev->md_io_tmpp) {

			struct page *page = alloc_page(GFP_NOIO);

			if (!page)

				goto force_diskless_dec;



			dev_warn(DEV, "Meta data's bdev logical_block_size = %d != %d\n",

			     logical_block_size, MD_SECTOR_SIZE);

			dev_warn(DEV, "Workaround engaged (has performance impact).\n");



			mdev->md_io_tmpp = page;

		}

	}



	if (!mdev->bitmap) {

		if (drbd_bm_init(mdev)) {

			retcode = ERR_NOMEM;
@@ -980,25 +999,6 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp 
		goto force_diskless_dec;

	}



	/* allocate a second IO page if logical_block_size != 512 */

	logical_block_size = bdev_logical_block_size(nbc->md_bdev);

	if (logical_block_size == 0)

		logical_block_size = MD_SECTOR_SIZE;



	if (logical_block_size != MD_SECTOR_SIZE) {

		if (!mdev->md_io_tmpp) {

			struct page *page = alloc_page(GFP_NOIO);

			if (!page)

				goto force_diskless_dec;



			dev_warn(DEV, "Meta data's bdev logical_block_size = %d != %d\n",

			     logical_block_size, MD_SECTOR_SIZE);

			dev_warn(DEV, "Workaround engaged (has performance impact).\n");



			mdev->md_io_tmpp = page;

		}

	}



	/* Reset the "barriers don't work" bits here, then force meta data to

	 * be written, to ensure we determine if barriers are supported. */

	if (nbc->dc.no_md_flush)