lkml.org 
[lkml]   [2023]   [Sep]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v9 03/11] btrfs: add support for inserting raid stripe extents
 	Hi David,

On Thu, 14 Sep 2023, David Sterba wrote:
> On Thu, Sep 14, 2023 at 09:06:58AM -0700, Johannes Thumshirn wrote:
>> Add support for inserting stripe extents into the raid stripe tree on
>> completion of every write that needs an extra logical-to-physical
>> translation when using RAID.
>>
>> Inserting the stripe extents happens after the data I/O has completed,
>> this is done to a) support zone-append and b) rule out the possibility of
>> a RAID-write-hole.
>>
>> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

>> --- /dev/null
>> +++ b/fs/btrfs/raid-stripe-tree.c
>> +static int btrfs_insert_striped_mirrored_raid_extents(
>> + struct btrfs_trans_handle *trans,
>> + struct btrfs_ordered_extent *ordered,
>> + u64 map_type)
>> +{
>> + 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;
>
> This will probably warn due to u64/u32 division.

Worse, it causes link failures in linux-next, as e.g. reported by
noreply@ellerman.id.au:

ERROR: modpost: "__udivdi3" [fs/btrfs/btrfs.ko] undefined!

So despite being aware of the issue, you still queued it?

The use of "int" for almost all variables is also a red flag:
- list_count_nodes() returns size_t,
- btrfs_bg_flags_to_raid_index() returns an enum.
- btrfs_raid_array[index].sub_stripes is u8,
- The result of the division may not fit in 32-bit.

Thanks for fixing, soon! ;-)

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

\
 
 \ /
  Last update: 2023-09-15 12:07    [W:0.307 / U:0.800 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site