Hi all, Directory parent pointers are stored as namespaced extended attributes of a file. Because parent pointers can consume up to 267 bytes of space and xattr names are 255 bytes at most, we cannot use the usual attr name lookup functions to find a parent pointer. This is solvable by introducing a new lookup mode that checks both the name and the value of the xattr. Therefore, introduce this new lookup mode. Because all parent pointer updates are logged, we must extend the xattr logging code to capture the VLOOKUP variants, and restore them when recovering logged operations. These new log formats are protected by the sb_incompat PARENT flag, so they do not need a separate log_incompat feature flag. 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=pptrs-attr-nvlookups xfsprogs git tree: https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=pptrs-attr-nvlookups --- fs/xfs/libxfs/xfs_attr.c | 57 +++++-- fs/xfs/libxfs/xfs_attr.h | 9 + fs/xfs/libxfs/xfs_attr_leaf.c | 45 ++++- fs/xfs/libxfs/xfs_da_btree.h | 10 + fs/xfs/libxfs/xfs_log_format.h | 29 +++ fs/xfs/xfs_attr_item.c | 347 ++++++++++++++++++++++++++++++++++------ fs/xfs/xfs_attr_item.h | 2 fs/xfs/xfs_xattr.c | 5 + 8 files changed, 425 insertions(+), 79 deletions(-)
