76068cae63
When testing subpage defrag support, I always find some strange inode nbytes error, after a lot of debugging, it turns out that defrag_lookup_extent() is using PAGE_SIZE as size for lookup_extent_mapping(). Since lookup_extent_mapping() is calling __lookup_extent_mapping() with @strict == 1, this means any extent map smaller than one page will be ignored, prevent subpage defrag to grab a correct extent map. There are quite some PAGE_SIZE usage in ioctl.c, but most of them are correct usages, and can be one of the following cases: - ioctl structure size check We want ioctl structure to be contained inside one page. - real page operations The remaining cases in defrag_lookup_extent() and check_defrag_in_cache() will be addressed in this patch. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.