| config AUFS_FS |
| tristate "Aufs (Advanced multi layered unification filesystem) support" |
| help |
| Aufs is a stackable unification filesystem such as Unionfs, |
| which unifies several directories and provides a merged single |
| directory. |
| In the early days, aufs was entirely re-designed and |
| re-implemented Unionfs Version 1.x series. Introducing many |
| original ideas, approaches and improvements, it becomes totally |
| different from Unionfs while keeping the basic features. |
| |
| if AUFS_FS |
| choice |
| prompt "Maximum number of branches" |
| default AUFS_BRANCH_MAX_127 |
| help |
| Specifies the maximum number of branches (or member directories) |
| in a single aufs. The larger value consumes more system |
| resources and has a minor impact to performance. |
| config AUFS_BRANCH_MAX_127 |
| bool "127" |
| help |
| Specifies the maximum number of branches (or member directories) |
| in a single aufs. The larger value consumes more system |
| resources and has a minor impact to performance. |
| config AUFS_BRANCH_MAX_511 |
| bool "511" |
| help |
| Specifies the maximum number of branches (or member directories) |
| in a single aufs. The larger value consumes more system |
| resources and has a minor impact to performance. |
| config AUFS_BRANCH_MAX_1023 |
| bool "1023" |
| help |
| Specifies the maximum number of branches (or member directories) |
| in a single aufs. The larger value consumes more system |
| resources and has a minor impact to performance. |
| config AUFS_BRANCH_MAX_32767 |
| bool "32767" |
| help |
| Specifies the maximum number of branches (or member directories) |
| in a single aufs. The larger value consumes more system |
| resources and has a minor impact to performance. |
| endchoice |
| |
| config AUFS_SBILIST |
| bool |
| depends on AUFS_MAGIC_SYSRQ || PROC_FS |
| default y |
| help |
| Automatic configuration for internal use. |
| When aufs supports Magic SysRq or /proc, enabled automatically. |
| |
| config AUFS_HNOTIFY |
| bool "Detect direct branch access (bypassing aufs)" |
| help |
| If you want to modify files on branches directly, eg. bypassing aufs, |
| and want aufs to detect the changes of them fully, then enable this |
| option and use 'udba=notify' mount option. |
| Currently there is only one available configuration, "fsnotify". |
| It will have a negative impact to the performance. |
| See detail in aufs.5. |
| |
| choice |
| prompt "method" if AUFS_HNOTIFY |
| default AUFS_HFSNOTIFY |
| config AUFS_HFSNOTIFY |
| bool "fsnotify" |
| select FSNOTIFY |
| endchoice |
| |
| config AUFS_EXPORT |
| bool "NFS-exportable aufs" |
| depends on EXPORTFS |
| help |
| If you want to export your mounted aufs via NFS, then enable this |
| option. There are several requirements for this configuration. |
| See detail in aufs.5. |
| |
| config AUFS_INO_T_64 |
| bool |
| depends on AUFS_EXPORT |
| depends on 64BIT && !(ALPHA || S390) |
| default y |
| help |
| Automatic configuration for internal use. |
| /* typedef unsigned long/int __kernel_ino_t */ |
| /* alpha and s390x are int */ |
| |
| config AUFS_RDU |
| bool "Readdir in userspace" |
| help |
| Aufs has two methods to provide a merged view for a directory, |
| by a user-space library and by kernel-space natively. The latter |
| is always enabled but sometimes large and slow. |
| If you enable this option, install the library in aufs2-util |
| package, and set some environment variables for your readdir(3), |
| then the work will be handled in user-space which generally |
| shows better performance in most cases. |
| See detail in aufs.5. |
| |
| config AUFS_PROC_MAP |
| bool "support for /proc/maps and lsof(1)" |
| depends on PROC_FS |
| help |
| When you issue mmap(2) in aufs, it is actually a direct mmap(2) |
| call to the file on the branch fs since the file in aufs is |
| purely virtual. And the file path printed in /proc/maps (and |
| others) will be the path on the branch fs. In most cases, it |
| does no harm. But some utilities like lsof(1) may confuse since |
| the utility or user may expect the file path in aufs to be |
| printed. |
| To address this issue, aufs provides a patch which introduces a |
| new member called vm_prfile into struct vm_are_struct. The patch |
| is meaningless without enabling this configuration since nobody |
| sets the new vm_prfile member. |
| If you don't apply the patch, then enabling this configuration |
| will cause a compile error. |
| This approach is fragile since if someone else make some changes |
| around vm_file, then vm_prfile may not work anymore. As a |
| workaround such case, aufs provides this configuration. If you |
| disable it, then lsof(1) may produce incorrect result but the |
| problem will be gone even if the aufs patch is applied (I hope). |
| |
| config AUFS_SP_IATTR |
| bool "Respect the attributes (mtime/ctime mainly) of special files" |
| help |
| When you write something to a special file, some attributes of it |
| (mtime/ctime mainly) may be updated. Generally such updates are |
| less important (actually some device drivers and NFS ignore |
| it). But some applications (such like test program) requires |
| such updates. If you need these updates, then enable this |
| configuration which introduces some overhead. |
| Currently this configuration handles FIFO only. |
| |
| config AUFS_SHWH |
| bool "Show whiteouts" |
| help |
| If you want to make the whiteouts in aufs visible, then enable |
| this option and specify 'shwh' mount option. Although it may |
| sounds like philosophy or something, but in technically it |
| simply shows the name of whiteout with keeping its behaviour. |
| |
| config AUFS_BR_RAMFS |
| bool "Ramfs (initramfs/rootfs) as an aufs branch" |
| help |
| If you want to use ramfs as an aufs branch fs, then enable this |
| option. Generally tmpfs is recommended. |
| Aufs prohibited them to be a branch fs by default, because |
| initramfs becomes unusable after switch_root or something |
| generally. If you sets initramfs as an aufs branch and boot your |
| system by switch_root, you will meet a problem easily since the |
| files in initramfs may be inaccessible. |
| Unless you are going to use ramfs as an aufs branch fs without |
| switch_root or something, leave it N. |
| |
| config AUFS_BR_FUSE |
| bool "Fuse fs as an aufs branch" |
| depends on FUSE_FS |
| select AUFS_POLL |
| help |
| If you want to use fuse-based userspace filesystem as an aufs |
| branch fs, then enable this option. |
| It implements the internal poll(2) operation which is |
| implemented by fuse only (curretnly). |
| |
| config AUFS_POLL |
| bool |
| help |
| Automatic configuration for internal use. |
| |
| config AUFS_BR_HFSPLUS |
| bool "Hfsplus as an aufs branch" |
| depends on HFSPLUS_FS |
| default y |
| help |
| If you want to use hfsplus fs as an aufs branch fs, then enable |
| this option. This option introduces a small overhead at |
| copying-up a file on hfsplus. |
| |
| config AUFS_BDEV_LOOP |
| bool |
| depends on BLK_DEV_LOOP |
| default y |
| help |
| Automatic configuration for internal use. |
| Convert =[ym] into =y. |
| |
| config AUFS_DEBUG |
| bool "Debug aufs" |
| help |
| Enable this to compile aufs internal debug code. |
| It will have a negative impact to the performance. |
| |
| config AUFS_MAGIC_SYSRQ |
| bool |
| depends on AUFS_DEBUG && MAGIC_SYSRQ |
| default y |
| help |
| Automatic configuration for internal use. |
| When aufs supports Magic SysRq, enabled automatically. |
| endif |
