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.
--
Trond Myklebust
Linux NFS client maintainer, PrimaryData
trond.myklebust@xxxxxxxxxxxxxxx
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