tmpfs: disallow CONFIG_TMPFS_INODE64 on alpha

As with s390, alpha is a 64-bit architecture with a 32-bit ino_t.  With
CONFIG_TMPFS_INODE64=y tmpfs mounts will get 64-bit inode numbers and
display "inode64" in the mount options, whereas passing "inode64" in the
mount options will fail.  This leads to erroneous behaviours such as
this:

  # mkdir mnt
  # mount -t tmpfs nodev mnt
  # mount -o remount,rw mnt
  mount: /home/ubuntu/mnt: mount point not mounted or bad option.

Prevent CONFIG_TMPFS_INODE64 from being selected on alpha.

Link: https://lkml.kernel.org/r/20210208215726.608197-1-seth.forshee@canonical.com
Fixes: ea3271f7196c ("tmpfs: support 64-bit inums per-sb")
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Chris Down <chris@chrisdown.name>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: <stable@vger.kernel.org>	[5.9+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/Kconfig b/fs/Kconfig
index 3347ec7bd83782e29dc6e3175fce4c33fedf20b9..da524c4d7b7e03f7d9a218f9e78ef0849b16de2d 100644 (file)
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -203,7 +203,7 @@ config TMPFS_XATTR
 
 config TMPFS_INODE64
        bool "Use 64-bit ino_t by default in tmpfs"
-       depends on TMPFS && 64BIT && !S390
+       depends on TMPFS && 64BIT && !(S390 || ALPHA)
        default n
        help
          tmpfs has historically used only inode numbers as wide as an unsigned