a13467ee7a
[SUSPICIOUS CODE] When refactoring scrub code, I noticed a very strange behavior around scrub_remap_extent(): if (sctx->is_dev_replace) scrub_remap_extent(fs_info, cur_logical, scrub_len, &cur_physical, &target_dev, &cur_mirror); As replace target is a 1:1 copy of the source device, thus physical offset inside the target should be the same as physical inside source, thus this remap call makes no sense to me. [REAL FUNCTIONALITY] After more investigation, the function name scrub_remap_extent() doesn't tell anything of the truth, nor does its if () condition. The real story behind this function is that, for scrub_pages() we never expect missing device, even for replacing missing device. What scrub_remap_extent() is really doing is to find a live mirror, and make later scrub_pages() to read data from the good copy, other than from the missing device and increase error counters unnecessarily. [IMPROVEMENT] We have no need to bother scrub_remap_extent() in scrub_simple_mirror() at all, we only need to call it before we call scrub_pages(). And rename the function to scrub_find_live_copy(), add extra comments on them. By this we can remove one parameter from scrub_extent(), and reduce the unnecessary calls to scrub_remap_extent() for regular replace. Signed-off-by: Qu Wenruo <wqu@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.