Commit 35e4c6c1 authored by Shin'ichiro Kawasaki's avatar Shin'ichiro Kawasaki Committed by Jens Axboe
Browse files

block: Hold invalidate_lock in BLKZEROOUT ioctl 



When BLKZEROOUT ioctl and data read race, the data read leaves stale
page cache. To avoid the stale page cache, hold invalidate_lock of the
block device file mapping. The stale page cache is observed when
blktests test case block/009 is modified to call "blkdiscard -z" command
and repeated hundreds of times.

This patch can be applied back to the stable kernel version v5.15.y.
Rework is required for older stable kernels.

Fixes: 22dd6d35 ("block: invalidate the page cache when issuing BLKZEROOUT")
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>
Link: https://lore.kernel.org/r/20211109104723.835533-3-shinichiro.kawasaki@wdc.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 7607c44c

block/ioctl.c

+9 −3
Original line number Diff line number Diff line
@@ -154,6 +154,7 @@ static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode, 
{

	uint64_t range[2];

	uint64_t start, end, len;

	struct inode *inode = bdev->bd_inode;

	int err;



	if (!(mode & FMODE_WRITE))
@@ -176,12 +177,17 @@ static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode, 
		return -EINVAL;



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

	filemap_invalidate_lock(inode->i_mapping);

	err = truncate_bdev_range(bdev, mode, start, end);

	if (err)

		return err;

		goto fail;



	return blkdev_issue_zeroout(bdev, start >> 9, len >> 9, GFP_KERNEL,

	err = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, GFP_KERNEL,

				   BLKDEV_ZERO_NOUNMAP);



fail:

	filemap_invalidate_unlock(inode->i_mapping);

	return err;

}



static int put_ushort(unsigned short __user *argp, unsigned short val)