This is a major rewrite of parts of union mounts, in particular the pathname lookup code. For more info about union mounts, see: http://valerieaurora.org/union/ The previous code had two important problems fixed in this series: - On file open, is_unionized() grabs vfsmount lock and walks up the mount tree even for non-union mounts. - Pathname lookup required three cut-n-pasted versions of two complex functions, one for each of cached/real/"hashed" lookups. This rewrite reduces the additional cost of a non-union lookup in a CONFIG_UNION_MOUNT kernel to either 1 or 2 mount flag tests (but adds the requirement that file systems be unioned only at their root directories). This rewrite implements lookup with one lookup_union() function for all types of lookups. This posted patch series includes only the union lookup, mount, and readdir patches and not the relatively uncontroversial whiteout and fallthru code. Rewrite of the in-kernel file copyup is next on my todo list. The entire patch set is against Viro's for-next branch, and available at: git://git.kernel.org/pub/scm/linux/kernel/git/val/linux-2.6.git Branch no_copyup. Please review! Thanks, -VAL Jan Blunck (3): union-mount: Introduce union_mount structure and basic operations union-mount: Drive the union cache via dcache union-mount: Call do_whiteout() on unlink and rmdir in unions Valerie Aurora (3): union-mount: Implement union lookup union-mount: Support for mounting union mount file systems union-mount: Copy up directory entries on first readdir() fs/Kconfig | 13 + fs/Makefile | 1 + fs/dcache.c | 17 ++ fs/namei.c | 199 +++++++++++++++- fs/namespace.c | 123 ++++++++++- fs/readdir.c | 9 + fs/union.c | 629 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/dcache.h | 28 +++ include/linux/mount.h | 3 + include/linux/union.h | 74 ++++++ 10 files changed, 1094 insertions(+), 2 deletions(-) create mode 100644 fs/union.c create mode 100644 include/linux/union.h -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
