On Sun, Mar 01, 2020 at 07:49:25AM -0700, Christoph Hellwig wrote:
> The swapon code itself sets sis->bdev up early, and performs various check
> on the block devices. Changing it later in the fact thus will cause a
> mismatch of capabilities and must be avoided.
What kind of mismatch? Are you talking about the bdi_cap_* and
blk_queue_nonrot() logic in swapon()? I wonder how much of that could
be moved to after the ->swapfile_activate call.
> The practical implication
> of this change is that it forbids swapping to the RT subvolume, which might
> have had all kinds of issues anyway.
<shrug> I didn't find any the one time I tried it on a pair of
homogeneous devices. :)
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/xfs/xfs_aops.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index 58e937be24ce..f9929a952ef1 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -637,7 +637,6 @@ xfs_iomap_swapfile_activate(
> struct file *swap_file,
> sector_t *span)
> {
> - sis->bdev = xfs_inode_buftarg(XFS_I(file_inode(swap_file)))->bt_bdev;
That said, btrfs copypasta'd this when they ported to iomap swapfile, so
that needs fixing too.
--D
> return iomap_swapfile_activate(sis, swap_file, span,
> &xfs_read_iomap_ops);
> }
> --
> 2.24.1
>
