Hi all, Dave pointed out some failures in xfs/270 when he upgraded Debian unstable and util-linux started using the new mount apis. Upon further inquiry I noticed that XFS is quite a hot mess when it encounters a filesystem with unrecognized rocompat bits set in the superblock. Whereas we used to allow readonly mounts under these conditions, a change to the sb write verifier several years ago resulted in the filesystem going down immediately because the post-mount log cleaning writes the superblock, which trips the sb write verifier on the unrecognized rocompat bit. I made the observation that the ROCOMPAT features RMAPBT and REFLINK both protect new log intent item types, which means that we actually cannot support recovering the log if we don't recognize all the rocompat bits. Therefore -- fix inode inactivation to work when we're recovering the log, disallow recovery when there's unrecognized rocompat bits, and don't clean the log if doing so would trip the rocompat checks. v2: change direction of series to allow log recovery on ro mounts 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 fstests git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=fix-ro-mounts --- tests/xfs/270 | 80 ++++++++++++++++++++++++++++++++++++++--------------- tests/xfs/270.out | 2 + 2 files changed, 59 insertions(+), 23 deletions(-)
