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@linux-foundation.org: reflow and reword comment, per Christoph]
Link: http://lkml.kernel.org/r/20191015085814.637837-1-naohiro.aota@wdc.com
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/swapfile.c b/mm/swapfile.c
index dab43523afdd351426ef5c92e5306a04a9820b36..bb3261d45b6a3ea6af720bee1abd0bc9a7a3e34e 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2887,6 +2887,13 @@ static int claim_swapfile(struct swap_info_struct *p, struct inode *inode)
                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;