copying files within a cifs-share currently result in the following
trace:
```
[ 495.388739] BUG: unable to handle page fault for address: fffffffffffffffe
[ 495.388744] #PF: supervisor read access in kernel mode
[ 495.388746] #PF: error_code(0x0000) - not-present page
[ 495.388747] PGD 172c3f067 P4D 172c3f067 PUD 172c41067 PMD 0
[ 495.388752] Oops: 0000 [#2] PREEMPT SMP NOPTI
[ 495.388754] CPU: 1 PID: 3894 Comm: cp Tainted: G D 6.5.0-32-generic #32-Ubuntu [ 495.388756] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 4.2023.08-4 02/15/2024
[ 495.388758] RIP: 0010:cifs_flush_folio+0x41/0xf0 [cifs]
...
```
a quick check identified proxmox-kernel-6.5.13-2 as the first affected
version, and `2dc07a11e269bfbe5589e99b60cdbae0118be979` as likely
source of the issue. The commit adapts the changes from
`7b2404a886f8b91250c31855d287e632123e1746` to work with the code in
kernel 6.1.
This is not needed as the relevant changes were made in 6.4 and
are already part of the 6.5 tree -
`66dabbb65d673aef40dd17bf62c042be8f6d4a4b`
reverting the commit fixes copying files within a samba share.
Tested/reproduced with:
* a VM with the kernel as cifs-client
* one very crude samba-share allowing guest-write access on a Debian
bookworm host
* as well as a share using cifscreds + multiuser (`mount.cifs(8)`)
* mounting the share, copying any file from one directory to another
on the same share (with `cp` and Thunar and Nautilus).
Reported to Ubuntu upstream at [1].
[0] https://lore.kernel.org/linux-mm/ZZhrpNJ3zxMR8wcU@eldamar.lan/
[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2055002
Reported-by: Daniela Häsler <daniela@proxmox.com>
Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>
803ddb6d55