Hi all, A longstanding deficiency in the online fs summary counter scrubbing code is that it hasn't any means to quiesce the incore percpu counters while it's running. There is no way to coordinate with other threads are reserving or freeing free space simultaneously, which leads to false error reports. Right now, if the discrepancy is large, we just sort of shrug and bail out with an incomplete flag, but this is lame. For repair activity, we actually /do/ need to stabilize the counters to get an accurate reading and install it in the percpu counter. To improve the former and enable the latter, allow the fscounters online fsck code to perform an exclusive mini-freeze on the filesystem. The exclusivity prevents userspace from thawing while we're running, and the mini-freeze means that we don't wait for the log to quiesce, which will make both speedier. If you're going to start using this mess, you probably ought to just pull from my git trees, which are linked below. This is an extraordinary way to destroy everything. Enjoy! Comments and questions are, as always, welcome. --D kernel git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfs-linux.git/log/?h=repair-fscounters fstests git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=repair-fscounters --- fs/super.c | 74 ++++++++++++++- fs/xfs/Makefile | 1 fs/xfs/scrub/fscounters.c | 185 ++++++++++++++++++++++++++++---------- fs/xfs/scrub/fscounters.h | 20 ++++ fs/xfs/scrub/fscounters_repair.c | 72 +++++++++++++++ fs/xfs/scrub/repair.h | 2 fs/xfs/scrub/scrub.c | 8 +- fs/xfs/scrub/scrub.h | 1 fs/xfs/scrub/trace.c | 1 fs/xfs/scrub/trace.h | 22 ++++- fs/xfs/xfs_super.c | 20 ++++ fs/xfs/xfs_super.h | 2 include/linux/fs.h | 3 + 13 files changed, 348 insertions(+), 63 deletions(-) create mode 100644 fs/xfs/scrub/fscounters.h create mode 100644 fs/xfs/scrub/fscounters_repair.c
