[lkml]   [2021]   [Feb]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
SubjectRe: [PATCH] tmpfs: Disallow CONFIG_TMPFS_INODE64 on s390
On Fri,  5 Feb 2021 17:06:20 -0600 Seth Forshee <> wrote:

> This feature requires ino_t be 64-bits, which is true for every
> 64-bit architecture but s390, so prevent this option from being
> selected there.

The previous patch nicely described the end-user impact of the bug.
This is especially important when requesting a -stable backport.

Here's what I ended up with:

From: Seth Forshee <>
Subject: tmpfs: disallow CONFIG_TMPFS_INODE64 on s390

Currently there is an assumption in tmpfs that 64-bit architectures also
have a 64-bit ino_t. This is not true on s390 which has 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, but passing the "inode64" mount
option will fail. This leads to the following behavior:

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

As mount sees "inode64" in the mount options and thus passes it in the
options for the remount.

So prevent CONFIG_TMPFS_INODE64 from being selected on s390.

Fixes: ea3271f7196c ("tmpfs: support 64-bit inums per-sb")
Signed-off-by: Seth Forshee <>
Cc: Chris Down <>
Cc: Hugh Dickins <>
Cc: Amir Goldstein <>
Cc: Heiko Carstens <>
Cc: Vasily Gorbik <>
Cc: Christian Borntraeger <>
Cc: <> [5.9+]
Signed-off-by: Andrew Morton <>

fs/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/Kconfig~tmpfs-disallow-config_tmpfs_inode64-on-s390
+++ a/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
+ depends on TMPFS && 64BIT && !S390
default n
tmpfs has historically used only inode numbers as wide as an unsigned
 \ /
  Last update: 2021-02-06 05:22    [W:0.186 / U:1.352 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site