On 24 Jan 2018, at 18:08, Trond Myklebust wrote:
> On Wed, 2018-01-24 at 09:48 -0500, Benjamin Coddington wrote:
>> It's possible that the device map is smaller than the offset into the
>> device for the I/O we're adding. This probably indicates an error of
>> some
>> sort (such as the dev->len = 0 due to the device being unreadable),
>> so
>> let's add a check for it and bail out. Otherwise, we risk botching
>> the bio
>> calculations that follow.
>>
>> Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
>> ---
>> fs/nfs/blocklayout/blocklayout.c | 9 +++++++--
>> 1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/nfs/blocklayout/blocklayout.c
>> b/fs/nfs/blocklayout/blocklayout.c
>> index 334570888649..6259ef20ee3e 100644
>> --- a/fs/nfs/blocklayout/blocklayout.c
>> +++ b/fs/nfs/blocklayout/blocklayout.c
>> @@ -137,6 +137,11 @@ bl_alloc_init_bio(int npg, struct block_device
>> *bdev, sector_t disk_sector,
>> return bio;
>> }
>>
>> +static bool offset_in_map(sector_t isect, struct pnfs_block_dev_map
>> *map)
>> +{
>> + return isect >= map->start && isect < map->start + map->len;
>> +}
>> +
>> static struct bio *
>> do_add_page_to_bio(struct bio *bio, int npg, int rw, sector_t isect,
>> struct page *page, struct pnfs_block_dev_map *map,
>> @@ -156,8 +161,8 @@ do_add_page_to_bio(struct bio *bio, int npg, int
>> rw, sector_t isect,
>>
>> /* translate to physical disk offset */
>> disk_addr = (u64)isect << SECTOR_SHIFT;
>> - if (disk_addr < map->start || disk_addr >= map->start + map-
>>> len) {
>> - if (!dev->map(dev, disk_addr, map))
>> + if (!offset_in_map(isect, map)) {
>> + if (!dev->map(dev, disk_addr, map) ||
>> !offset_in_map(isect, map))
>> return ERR_PTR(-EIO);
>> bio = bl_submit_bio(bio);
>> }
>
> I'm confused. While your patch does appear to make sense, there is
> other code in the same function that mixes type sector_t and disk
> offsets (including a line of the form 'disk_addr -= map->start').
>
> IOW: if this patch makes sense, then there is definitely more code to
> fix in the same function.
Yes, this is wrong. I think struct pnfs_block_dev_map should be byte
offsets not sectors. I'll send a patch for that, and then this one again.
Ben
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
