On Wednesday, August 30, 2017 5:20:10 AM IST Dave Chinner wrote:
> Everyone who tries to modify mkfs quickly learns that it is a pile
> of spaghetti, the only difference in opinion is whether it is a
> steaming, cold or rotten pile. This patchset attempts to untangle
> the ball of pasta and turn it into a set of clear, obvious
> operations that lead to a filesystem being formatted correctly.
>
> The patch series is really in three parts, splitting the code up
> into roughly three modules. The first part introduces a mkfs
> parameters structure and factors the on-disk formatting code to use
> only information in that structure. The second part introduces a
> command line input structure and factors the input parsing to use
> it. This requires a bunch of temporary code to keep the rest of
> the code working. The third part is factoring the input validation
> and geometry calculation code to use the input structure and put
> the output into the mkfs parameter structure and to remove all the
> temporary support code.
>
> The result is three modules - input parsing, validation+calculations
> and formatting - with well defined data flow between them. This also
> paves the way to supporting config files to set defaults via a
> separate (new) module. The overall data flow now looks like this:
>
> Build defaults --\
> ---> mkfs_default_params -> CLI -> mkfs_params
> config file -----/
>
> It is not worth spending a lot of time reviewing the temporary code
> that is added - it gets removed before the end of the series. No
> attempt has been made to ensure that mkfs works 100% correctly after
> each patch is applied - the only guarantee is that it will build
> cleanly. It /should/ work if a bisect lands in the middle of the
> series, but trying to exhaustively test each patch is OK would take
> more effort than it is worth. As such, testing has only been
> performed on the whole series.
>
> The new output from mkfs to indicate where it has sourced the
> defaults from causes xfstests to have conniptions. This requires
> some updates to the mkfs output filters that are already in place
> but it is a fairly trivial update. Test xfs/191 has a couple of new
> failures, but that is because the new code now correctly parses
> things like agsize so that block and sector size based
> specifications work with default mkfs values. This will require test
> updates.
>
> Future work will be to split the xfs_mkfs.c file into a file per
> module (i.e. seperate files for CLI parsing, mkfs formating,
> validation+calculation and, finally, one for config file support),
> but otherwise the majority of the factoring work is now complete.
>
> Comments, flames, etc all welcome.
>
Hi Dave,
For 4k blocksized xfs filesystem on ppc64, xfs/058 fails with mkfs refactor
patchset applied.
[root@localhost xfstests-dev]# ./check xfs/058
FSTYP -- xfs (debug)
PLATFORM -- Linux/ppc64 localhost 4.13.0-next-20170905-00001-g9730219
MKFS_OPTIONS -- -f -bsize=4096 /dev/loop1
MOUNT_OPTIONS -- /dev/loop1 /mnt/btrfs-xfstest-scratch
xfs/058 2s ... - output mismatch (see /root/repos/xfstests-dev/results//xfs/058.out.bad)
--- tests/xfs/058.out 2017-09-03 02:23:13.432063287 -0500
+++ /root/repos/xfstests-dev/results//xfs/058.out.bad 2017-09-07 05:07:49.850183977 -0500
@@ -13,16 +13,16 @@
fdblocks = 9223372036854775807
Test verb middlebit
Allowing fuzz of corrupted data with good CRC
-fdblocks = 9223372034707292159
+fdblocks = 9223372036854775807
Test verb lastbit
Allowing fuzz of corrupted data with good CRC
...
(Run 'diff -u tests/xfs/058.out /root/repos/xfstests-dev/results//xfs/058.out.bad' to see the entire diff)
Ran: xfs/058
Failures: xfs/058
Failed 1 of 1 tests
I will debug this further and let you know about the results.
Also, xfs/206 fails because the line
"Default configuration sourced from package build definitions" isn't getting
filtered out.
--
chandan
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