Hi all, This series employs atomic extent swapping to enable safe reconstruction of directory data. For now, XFS does not support reverse directory links (aka parent pointers), so we can only salvage the dirents of a directory and construct a new structure. Directory repair therefore consists of five main parts: First, we walk the existing directory to salvage as many entries as we can, by adding them as new directory entries to the repair temp dir. Second, we validate the parent pointer found in the directory. If one was not found, we scan the entire filesystem looking for a potential parent. Third, we use atomic extent swaps to exchange the entire data fork between the two directories. Fourth, we reap the old directory blocks as carefully as we can. To wrap up the directory repair code, we need to add to the regular filesystem the ability to free all the data fork blocks in a directory. This does not change anything with normal directories, since they must still unlink and shrink one entry at a time. However, this will facilitate freeing of partially-inactivated temporary directories during log recovery. The second half of this patchset implements repairs for the dotdot entries of directories. For now there is only rudimentary support for this, because there are no directory parent pointers, so the best we can do is scanning the filesystem and the VFS dcache for answers. 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-dirs xfsprogs git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=repair-dirs fstests git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfstests-dev.git/log/?h=repair-dirs --- fs/xfs/Makefile | 2 fs/xfs/scrub/dir.c | 9 fs/xfs/scrub/dir_repair.c | 1179 ++++++++++++++++++++++++++++++++++++++++++ fs/xfs/scrub/iscan.c | 7 fs/xfs/scrub/iscan.h | 3 fs/xfs/scrub/nlinks.c | 23 + fs/xfs/scrub/nlinks_repair.c | 9 fs/xfs/scrub/parent.c | 3 fs/xfs/scrub/parent.h | 17 + fs/xfs/scrub/parent_repair.c | 461 ++++++++++++++++ fs/xfs/scrub/repair.c | 29 + fs/xfs/scrub/repair.h | 7 fs/xfs/scrub/scrub.c | 4 fs/xfs/scrub/tempfile.c | 13 fs/xfs/scrub/tempfile.h | 2 fs/xfs/scrub/trace.h | 138 +++++ fs/xfs/xfs_inode.c | 51 ++ 17 files changed, 1953 insertions(+), 4 deletions(-) create mode 100644 fs/xfs/scrub/dir_repair.c create mode 100644 fs/xfs/scrub/parent.h create mode 100644 fs/xfs/scrub/parent_repair.c
