From: Naohiro Aota <naohiro.aota@xxxxxxx> Subject: mm, swap: disallow swapon() on zoned block devices A zoned block device consists of a number of zones. Zones are either conventional and accepting random writes or sequential and requiring that writes be issued in LBA order from each zone write pointer position. For the write restriction, zoned block devices are not suitable for a swap device. Disallow swapon on them. [akpm@xxxxxxxxxxxxxxxxxxxx: reflow and reword comment, per Christoph] Link: http://lkml.kernel.org/r/20191015085814.637837-1-naohiro.aota@xxxxxxx Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: "Theodore Y. Ts'o" <tytso@xxxxxxx> Cc: Hannes Reinecke <hare@xxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/swapfile.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/mm/swapfile.c~mm-swap-disallow-swapon-on-zoned-block-devices +++ a/mm/swapfile.c @@ -2887,6 +2887,13 @@ static int claim_swapfile(struct swap_in error = set_blocksize(p->bdev, PAGE_SIZE); if (error < 0) return error; + /* + * Zoned block devices contain zones that have a sequential + * write only restriction. Hence zoned block devices are not + * suitable for swapping. Disallow them here. + */ + if (blk_queue_is_zoned(p->bdev->bd_queue)) + return -EINVAL; p->flags |= SWP_BLKDEV; } else if (S_ISREG(inode->i_mode)) { p->bdev = inode->i_sb->s_bdev; _
