[PATCHSET v29.0 04/28] xfs: online repair of file link counts

Darrick J. Wong
2023-12-31T19:26:24Z

Hi all,

Now that we've created the infrastructure to perform live scans of every
file in the filesystem and the necessary hook infrastructure to observe
live updates, use it to scan directories to compute the correct link
counts for files in the filesystem, and reset those link counts.

This patchset creates a tailored readdir implementation for scrub
because the regular version has to cycle ILOCKs to copy information to
userspace. We can't cycle the ILOCK during the nlink scan and we don't
need all the other VFS support code (maintaining a readdir cursor and
translating XFS structures to VFS structures and back) so it was easier
to duplicate the code.

If you're going to start using this code, I strongly recommend pulling
from my git trees, which are linked below.

This has been running on the djcloud for months with no problems. 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=scrub-nlinks

xfsprogs git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=scrub-nlinks

fstests git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=scrub-nlinks
---
fs/xfs/Makefile | 2
fs/xfs/libxfs/xfs_fs.h | 4
fs/xfs/libxfs/xfs_health.h | 4
fs/xfs/scrub/common.c | 3
fs/xfs/scrub/common.h | 1
fs/xfs/scrub/health.c | 1
fs/xfs/scrub/nlinks.c | 930 ++++++++++++++++++++++++++++++++++++++++++
fs/xfs/scrub/nlinks.h | 102 +++++
fs/xfs/scrub/nlinks_repair.c | 223 ++++++++++
fs/xfs/scrub/repair.h | 2
fs/xfs/scrub/scrub.c | 9
fs/xfs/scrub/scrub.h | 5
fs/xfs/scrub/stats.c | 1
fs/xfs/scrub/trace.c | 2
fs/xfs/scrub/trace.h | 183 ++++++++
fs/xfs/xfs_health.c | 1
fs/xfs/xfs_inode.c | 108 +++++
fs/xfs/xfs_inode.h | 31 +
fs/xfs/xfs_mount.h | 3
fs/xfs/xfs_super.c | 2
fs/xfs/xfs_symlink.c | 1
21 files changed, 1614 insertions(+), 4 deletions(-)
create mode 100644 fs/xfs/scrub/nlinks.c
create mode 100644 fs/xfs/scrub/nlinks.h
create mode 100644 fs/xfs/scrub/nlinks_repair.c