Messages in this thread Patch in this message |  | | Date | Fri, 5 Feb 2021 16:05:51 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] tmpfs: Disallow CONFIG_TMPFS_INODE64 on s390 |
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On Fri, 5 Feb 2021 17:06:20 -0600 Seth Forshee <seth.forshee@canonical.com> 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 <seth.forshee@canonical.com> 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.
Link: https://lkml.kernel.org/r/20210205230620.518245-1-seth.forshee@canonical.com Fixes: ea3271f7196c ("tmpfs: support 64-bit inums per-sb") Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Cc: Chris Down <chris@chrisdown.name> Cc: Hugh Dickins <hughd@google.com> Cc: Amir Goldstein <amir73il@gmail.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: <stable@vger.kernel.org> [5.9+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> ---
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 help tmpfs has historically used only inode numbers as wide as an unsigned _
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