Commit 86399ea0 authored by Shin'ichiro Kawasaki's avatar Shin'ichiro Kawasaki Committed by Jens Axboe
Browse files

block: Hold invalidate_lock in BLKRESETZONE ioctl 



When BLKRESETZONE ioctl and data read race, the data read leaves stale
page cache. The commit e5113505 ("block: Discard page cache of zone
reset target range") added page cache truncation to avoid stale page
cache after the ioctl. However, the stale page cache still can be read
during the reset zone operation for the ioctl. To avoid the stale page
cache completely, hold invalidate_lock of the block device file mapping.

Fixes: e5113505 ("block: Discard page cache of zone reset target range")
Signed-off-by: default avatarShin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Cc: stable@vger.kernel.org # v5.15
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211111085238.942492-1-shinichiro.kawasaki@wdc.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b131f201

block/blk-zoned.c

+5 −10
Original line number Diff line number Diff line
@@ -429,9 +429,10 @@ int blkdev_zone_mgmt_ioctl(struct block_device *bdev, fmode_t mode, 
		op = REQ_OP_ZONE_RESET;



		/* Invalidate the page cache, including dirty pages. */

		filemap_invalidate_lock(bdev->bd_inode->i_mapping);

		ret = blkdev_truncate_zone_range(bdev, mode, &zrange);

		if (ret)

			return ret;

			goto fail;

		break;

	case BLKOPENZONE:

		op = REQ_OP_ZONE_OPEN;
@@ -449,15 +450,9 @@ int blkdev_zone_mgmt_ioctl(struct block_device *bdev, fmode_t mode, 
	ret = blkdev_zone_mgmt(bdev, op, zrange.sector, zrange.nr_sectors,

			       GFP_KERNEL);



	/*

	 * Invalidate the page cache again for zone reset: writes can only be

	 * direct for zoned devices so concurrent writes would not add any page

	 * to the page cache after/during reset. The page cache may be filled

	 * again due to concurrent reads though and dropping the pages for

	 * these is fine.

	 */

	if (!ret && cmd == BLKRESETZONE)

		ret = blkdev_truncate_zone_range(bdev, mode, &zrange);

fail:

	if (cmd == BLKRESETZONE)

		filemap_invalidate_unlock(bdev->bd_inode->i_mapping);



	return ret;

}