On Fri, 5 Feb 2021, Andrew Morton wrote: > On Fri, 5 Feb 2021 17:06:20 -0600 Seth Forshee <seth.forshee@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> > 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@xxxxxxxxxxxxx > Fixes: ea3271f7196c ("tmpfs: support 64-bit inums per-sb") > Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> > Cc: Chris Down <chris@xxxxxxxxxxxxxx> > Cc: Hugh Dickins <hughd@xxxxxxxxxx> Thank you Seth: now that you've fixed Kirill's alpha observation too, Acked-by: Hugh Dickins <hughd@xxxxxxxxxx> > Cc: Amir Goldstein <amir73il@xxxxxxxxx> > Cc: Heiko Carstens <hca@xxxxxxxxxxxxx> > Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> > Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> [5.9+] > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > --- > > 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 > _ > >
