Hi all, Currently, directory updates (link, unlink, rename) only hold the ILOCK for the first transaction in the chain. The first transaction is where we perform all the directory updates, so this has sufficed to coordinate access to the directory itself. With parent pointers, we need to hold both directories and children ILOCKed across the entire directory update transaction chain so that other threads never see an inconsistent edge state (parent -> child and parent <- child). Prepare for this by making the directory update code hold all the ILOCKs. There's a subtle issue with online rmapbt repair that gets fixed here. Space allocations performed as part of a directory update result in deferred rmap updates later in the chain. With the current code, the directory ILOCK (but not the IOLOCK) is dropped before the rmapbt updates are performed. As a result, the online rmapbt repair scanner has to hold each directory's IOLOCK and ILOCK to coordinate with writer threads correctly. This change makes it so that online repair no longer has to hold the directory IOLOCK, which makes the locking model here consistent with the other repair scanners. 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. kernel git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfs-linux.git/log/?h=pptrs-hold-ilocks --- fs/xfs/xfs_inode.c | 65 ++++++++++++++++++++++++++++++++++++++------------ fs/xfs/xfs_qm.c | 4 ++- fs/xfs/xfs_symlink.c | 2 ++ fs/xfs/xfs_trans.c | 9 +++++-- 4 files changed, 61 insertions(+), 19 deletions(-)
