fs/aufs/Kconfig

   1 # SPDX-License-Identifier: GPL-2.0
   2 config AUFS_FS
   3         tristate "Aufs (Advanced multi layered unification filesystem) support"
   4         help
   5         Aufs is a stackable unification filesystem such as Unionfs,
   6         which unifies several directories and provides a merged single
   7         directory.
   8         In the early days, aufs was entirely re-designed and
   9         re-implemented Unionfs Version 1.x series. Introducing many
  10         original ideas, approaches and improvements, it becomes totally
  11         different from Unionfs while keeping the basic features.
  12
  13 if AUFS_FS
  14 choice
  15         prompt "Maximum number of branches"
  16         default AUFS_BRANCH_MAX_127
  17         help
  18         Specifies the maximum number of branches (or member directories)
  19         in a single aufs. The larger value consumes more system
  20         resources and has a minor impact to performance.
  21 config AUFS_BRANCH_MAX_127
  22         bool "127"
  23         help
  24         Specifies the maximum number of branches (or member directories)
  25         in a single aufs. The larger value consumes more system
  26         resources and has a minor impact to performance.
  27 config AUFS_BRANCH_MAX_511
  28         bool "511"
  29         help
  30         Specifies the maximum number of branches (or member directories)
  31         in a single aufs. The larger value consumes more system
  32         resources and has a minor impact to performance.
  33 config AUFS_BRANCH_MAX_1023
  34         bool "1023"
  35         help
  36         Specifies the maximum number of branches (or member directories)
  37         in a single aufs. The larger value consumes more system
  38         resources and has a minor impact to performance.
  39 config AUFS_BRANCH_MAX_32767
  40         bool "32767"
  41         help
  42         Specifies the maximum number of branches (or member directories)
  43         in a single aufs. The larger value consumes more system
  44         resources and has a minor impact to performance.
  45 endchoice
  46
  47 config AUFS_SBILIST
  48         bool
  49         depends on AUFS_MAGIC_SYSRQ || PROC_FS
  50         default y
  51         help
  52         Automatic configuration for internal use.
  53         When aufs supports Magic SysRq or /proc, enabled automatically.
  54
  55 config AUFS_HNOTIFY
  56         bool "Detect direct branch access (bypassing aufs)"
  57         help
  58         If you want to modify files on branches directly, eg. bypassing aufs,
  59         and want aufs to detect the changes of them fully, then enable this
  60         option and use 'udba=notify' mount option.
  61         Currently there is only one available configuration, "fsnotify".
  62         It will have a negative impact to the performance.
  63         See detail in aufs.5.
  64
  65 choice
  66         prompt "method" if AUFS_HNOTIFY
  67         default AUFS_HFSNOTIFY
  68 config AUFS_HFSNOTIFY
  69         bool "fsnotify"
  70         select FSNOTIFY
  71 endchoice
  72
  73 config AUFS_EXPORT
  74         bool "NFS-exportable aufs"
  75         depends on EXPORTFS
  76         help
  77         If you want to export your mounted aufs via NFS, then enable this
  78         option. There are several requirements for this configuration.
  79         See detail in aufs.5.
  80
  81 config AUFS_INO_T_64
  82         bool
  83         depends on AUFS_EXPORT
  84         depends on 64BIT && !(ALPHA || S390)
  85         default y
  86         help
  87         Automatic configuration for internal use.
  88         /* typedef unsigned long/int __kernel_ino_t */
  89         /* alpha and s390x are int */
  90
  91 config AUFS_XATTR
  92         bool "support for XATTR/EA (including Security Labels)"
  93         help
  94         If your branch fs supports XATTR/EA and you want to make them
  95         available in aufs too, then enable this opsion and specify the
  96         branch attributes for EA.
  97         See detail in aufs.5.
  98
  99 config AUFS_FHSM
 100         bool "File-based Hierarchical Storage Management"
 101         help
 102         Hierarchical Storage Management (or HSM) is a well-known feature
 103         in the storage world. Aufs provides this feature as file-based.
 104         with multiple branches.
 105         These multiple branches are prioritized, ie. the topmost one
 106         should be the fastest drive and be used heavily.
 107
 108 config AUFS_RDU
 109         bool "Readdir in userspace"
 110         help
 111         Aufs has two methods to provide a merged view for a directory,
 112         by a user-space library and by kernel-space natively. The latter
 113         is always enabled but sometimes large and slow.
 114         If you enable this option, install the library in aufs2-util
 115         package, and set some environment variables for your readdir(3),
 116         then the work will be handled in user-space which generally
 117         shows better performance in most cases.
 118         See detail in aufs.5.
 119
 120 config AUFS_DIRREN
 121         bool "Workaround for rename(2)-ing a directory"
 122         help
 123         By default, aufs returns EXDEV error in renameing a dir who has
 124         his child on the lower branch, since it is a bad idea to issue
 125         rename(2) internally for every lower branch. But user may not
 126         accept this behaviour. So here is a workaround to allow such
 127         rename(2) and store some extra infromation on the writable
 128         branch. Obviously this costs high (and I don't like it).
 129         To use this feature, you need to enable this configuration AND
 130         to specify the mount option `dirren.'
 131         See details in aufs.5 and the design documents.
 132
 133 config AUFS_SHWH
 134         bool "Show whiteouts"
 135         help
 136         If you want to make the whiteouts in aufs visible, then enable
 137         this option and specify 'shwh' mount option. Although it may
 138         sounds like philosophy or something, but in technically it
 139         simply shows the name of whiteout with keeping its behaviour.
 140
 141 config AUFS_BR_RAMFS
 142         bool "Ramfs (initramfs/rootfs) as an aufs branch"
 143         help
 144         If you want to use ramfs as an aufs branch fs, then enable this
 145         option. Generally tmpfs is recommended.
 146         Aufs prohibited them to be a branch fs by default, because
 147         initramfs becomes unusable after switch_root or something
 148         generally. If you sets initramfs as an aufs branch and boot your
 149         system by switch_root, you will meet a problem easily since the
 150         files in initramfs may be inaccessible.
 151         Unless you are going to use ramfs as an aufs branch fs without
 152         switch_root or something, leave it N.
 153
 154 config AUFS_BR_FUSE
 155         bool "Fuse fs as an aufs branch"
 156         depends on FUSE_FS
 157         select AUFS_POLL
 158         help
 159         If you want to use fuse-based userspace filesystem as an aufs
 160         branch fs, then enable this option.
 161         It implements the internal poll(2) operation which is
 162         implemented by fuse only (curretnly).
 163
 164 config AUFS_POLL
 165         bool
 166         help
 167         Automatic configuration for internal use.
 168
 169 config AUFS_BR_HFSPLUS
 170         bool "Hfsplus as an aufs branch"
 171         depends on HFSPLUS_FS
 172         default y
 173         help
 174         If you want to use hfsplus fs as an aufs branch fs, then enable
 175         this option. This option introduces a small overhead at
 176         copying-up a file on hfsplus.
 177
 178 config AUFS_BDEV_LOOP
 179         bool
 180         depends on BLK_DEV_LOOP
 181         default y
 182         help
 183         Automatic configuration for internal use.
 184         Convert =[ym] into =y.
 185
 186 config AUFS_DEBUG
 187         bool "Debug aufs"
 188         help
 189         Enable this to compile aufs internal debug code.
 190         It will have a negative impact to the performance.
 191
 192 config AUFS_MAGIC_SYSRQ
 193         bool
 194         depends on AUFS_DEBUG && MAGIC_SYSRQ
 195         default y
 196         help
 197         Automatic configuration for internal use.
 198         When aufs supports Magic SysRq, enabled automatically.
 199 endif