Linux kernel modifications for the Kernel Hacking exam
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Rafael Rocha 3d882cca73 scsi: st: Fix input/output error on empty drive reset
A previous change was introduced to prevent data loss during a power-on
reset when a tape is present inside the drive. This commit set the
"pos_unknown" flag to true to avoid operations that could compromise data
by performing actions from an untracked position. The relevant change is
commit 9604eea5bd ("scsi: st: Add third party poweron reset handling")

As a consequence of this change, a new issue has surfaced: the driver now
returns an "Input/output error" even for empty drives when the drive, host,
or bus is reset. This issue stems from the "flush_buffer" function, which
first checks whether the "pos_unknown" flag is set. If the flag is set, the
user will encounter an "Input/output error" until the tape position is
known again. This behavior differs from the previous implementation, where
empty drives were not affected at system start up time, allowing tape
software to send commands to the driver to retrieve the drive's status and
other information.

The current behavior prioritizes the "pos_unknown" flag over the
"ST_NO_TAPE" status, leading to issues for software that detects drives
during system startup. This software will receive an "Input/output error"
until a tape is loaded and its position is known.

To resolve this, the "ST_NO_TAPE" status should take priority when the
drive is empty, allowing communication with the drive following a power-on
reset. At the same time, the change should continue to protect data by
maintaining the "pos_unknown" flag when the drive contains a tape and its
position is unknown.

Signed-off-by: Rafael Rocha <rrochavi@fnal.gov>
Link: https://lore.kernel.org/r/20240905173921.10944-1-rrochavi@fnal.gov
Fixes: 9604eea5bd ("scsi: st: Add third party poweron reset handling")
Acked-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2024-09-12 20:07:11 -04:00
arch minmax: add a few more MIN_T/MAX_T users 2024-07-28 13:41:14 -07:00
block scsi: block: Don't check REQ_ATOMIC for reads 2024-08-12 18:03:38 -04:00
certs kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
crypto crypto: testmgr - generate power-of-2 lengths more often 2024-07-13 11:50:28 +12:00
Documentation scsi: ufs: Add HCI capabilities sysfs group 2024-08-12 22:11:24 -04:00
drivers scsi: st: Fix input/output error on empty drive reset 2024-09-12 20:07:11 -04:00
fs This pull request contains updates (actually, just fixes) for UBI and UBIFS: 2024-07-28 11:51:51 -07:00
include scsi: core: Remove obsoleted declaration for scsi_driverbyte_string() 2024-08-28 21:03:11 -04:00
init Rust changes for v6.11 2024-07-27 13:44:54 -07:00
io_uring io_uring/napi: pass ktime to io_napi_adjust_timeout 2024-07-26 08:31:59 -06:00
ipc sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
kernel Fixes and minor updates for the timer migration code: 2024-07-27 10:19:55 -07:00
lib Rust changes for v6.11 2024-07-27 13:44:54 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/page_alloc: fix pcp->count race between drain_pages_zone() vs __rmqueue_pcplist() 2024-07-26 14:33:09 -07:00
net minmax: add a few more MIN_T/MAX_T users 2024-07-28 13:41:14 -07:00
rust Rust changes for v6.11 2024-07-27 13:44:54 -07:00
samples Driver core changes for 6.11-rc1 2024-07-25 10:42:22 -07:00
scripts Kbuild fixes for v6.11 2024-07-28 14:02:48 -07:00
security apparmor-pr-2024-07-24 PR 2024-07-25 2024-07-27 13:28:39 -07:00
sound Devicetree fixes for 6.11, part 1 2024-07-27 12:46:16 -07:00
tools turbostat release 2024.07.26 2024-07-28 10:52:15 -07:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM generic changes for 6.11 2024-07-16 09:51:36 -04:00
.clang-format Docs: Move clang-format from process/ to dev-tools/ 2024-06-26 16:36:00 -06:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: add script and target to generate pacman package 2024-07-22 01:24:22 +09:00
.mailmap MAINTAINERS: mailmap: update James Clark's email address 2024-07-26 14:32:35 -07:00
.rustfmt.toml
COPYING
CREDITS tracing: Update of MAINTAINERS and CREDITS file 2024-07-18 14:08:42 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig
MAINTAINERS CXL for v6.11 merge window 2024-07-28 09:33:28 -07:00
Makefile Linux 6.11-rc1 2024-07-28 14:19:55 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.