Eric Sandeen wrote:
> In some cases we can reach ext4_da_writepages() with
> wbc->nr_to_write == LONG_MAX, !range_cyclic, and range_whole=1;
> in this case we will try to bump it up by a factor of 8, which
> leads to a desired_nr_to_write value of -8.
Sorry Ted, hold off on this, it should have been LLONG_MAX of course,
and I'm still looking for one other bit of brokennes I see.
The 1/2 patch should be good though.
-Eric
> We still get through the logic without actually changing
> wbc->nr_to_write because the other tests which would change
> it don't trip due to the negative value, but it seems dangerous
> to overflow desired_nr_to_write in the interim, it's not an
> obvious situation.
>
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> ---
>
> (V2 minor commit message edits)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 93497f6..2e72a4a 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3004,9 +3004,11 @@ static int ext4_da_writepages(struct address_space *mapping,
> * sbi->max_writeback_mb_bump whichever is smaller.
> */
> max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT);
> - if (!range_cyclic && range_whole)
> - desired_nr_to_write = wbc->nr_to_write * 8;
> - else
> + if (!range_cyclic && range_whole) {
> + desired_nr_to_write = wbc->nr_to_write;
> + if (desired_nr_to_write != LONG_MAX)
> + desired_nr_to_write *= 8;
> + } else
> desired_nr_to_write = ext4_num_dirty_pages(inode, index,
> max_pages);
> if (desired_nr_to_write > max_pages)
>
>
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