Messages in this thread | | | From | Johannes Thumshirn <> | Subject | Re: [PATCH 1/4] btrfs: fix 64bit division in btrfs_insert_striped_mirrored_raid_extents | Date | Mon, 18 Sep 2023 15:03:10 +0000 |
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On 18.09.23 16:19, Geert Uytterhoeven wrote: > Hi Johannes, > > On Mon, Sep 18, 2023 at 4:14 PM Johannes Thumshirn > <johannes.thumshirn@wdc.com> wrote: >> Fix modpost error due to 64bit division on 32bit systems in >> btrfs_insert_striped_mirrored_raid_extents. >> >> Cc: Geert Uytterhoeven <geert@linux-m68k.org> >> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> > > Thanks for your patch! > >> --- a/fs/btrfs/raid-stripe-tree.c >> +++ b/fs/btrfs/raid-stripe-tree.c >> @@ -148,10 +148,10 @@ static int btrfs_insert_striped_mirrored_raid_extents( >> { >> struct btrfs_io_context *bioc; >> struct btrfs_io_context *rbioc; >> - const int nstripes = list_count_nodes(&ordered->bioc_list); >> - const int index = btrfs_bg_flags_to_raid_index(map_type); >> - const int substripes = btrfs_raid_array[index].sub_stripes; >> - const int max_stripes = trans->fs_info->fs_devices->rw_devices / substripes; >> + const size_t nstripes = list_count_nodes(&ordered->bioc_list); >> + const enum btrfs_raid_types index = btrfs_bg_flags_to_raid_index(map_type); >> + const u8 substripes = btrfs_raid_array[index].sub_stripes; >> + const int max_stripes = div_u64(trans->fs_info->fs_devices->rw_devices, substripes); > > What if the quotient does not fit in a signed 32-bit value?
Then you've bought a lot of HDDs ;-)
Jokes aside, yes this is theoretically correct. Dave can you fix max_stripes up to be u64 when applying?
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