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Brian Foster 669c867972 xfs: serialize unaligned dio writes against all other dio writes
commit 2032a8a27b upstream.

XFS applies more strict serialization constraints to unaligned
direct writes to accommodate things like direct I/O layer zeroing,
unwritten extent conversion, etc. Unaligned submissions acquire the
exclusive iolock and wait for in-flight dio to complete to ensure
multiple submissions do not race on the same block and cause data
corruption.

This generally works in the case of an aligned dio followed by an
unaligned dio, but the serialization is lost if I/Os occur in the
opposite order. If an unaligned write is submitted first and
immediately followed by an overlapping, aligned write, the latter
submits without the typical unaligned serialization barriers because
there is no indication of an unaligned dio still in-flight. This can
lead to unpredictable results.

To provide proper unaligned dio serialization, require that such
direct writes are always the only dio allowed in-flight at one time
for a particular inode. We already acquire the exclusive iolock and
drain pending dio before submitting the unaligned dio. Wait once
more after the dio submission to hold the iolock across the I/O and
prevent further submissions until the unaligned I/O completes. This
is heavy handed, but consistent with the current pre-submission
serialization for unaligned direct writes.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-26 09:14:28 +02:00
arch perf/x86/amd/uncore: Set the thread mask for F17h L3 PMCs 2019-07-26 09:14:26 +02:00
block blk-iolatency: only account submitted bios 2019-07-26 09:14:09 +02:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: chacha20poly1305 - fix atomic sleep when using async algorithm 2019-07-26 09:14:19 +02:00
Documentation x86/atomic: Fix smp_mb__{before,after}_atomic() 2019-07-26 09:14:08 +02:00
drivers libnvdimm/pfn: fix fsdax-mode namespace info-block zero-fields 2019-07-26 09:14:27 +02:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs xfs: serialize unaligned dio writes against all other dio writes 2019-07-26 09:14:28 +02:00
include include/asm-generic/bug.h: fix "cut here" for WARN_ON for __WARN_TAINT architectures 2019-07-26 09:14:28 +02:00
init initramfs: free initrd memory if opening /initrd.image fails 2019-06-15 11:54:01 +02:00
ipc ipc: prevent lockup on alloc_msg and free_msg 2019-06-15 11:54:00 +02:00
kernel padata: use smp_mb in padata_reorder to avoid orphaned padata jobs 2019-07-26 09:14:25 +02:00
lib lib/scatterlist: Fix mapping iterator when sg->offset is greater than PAGE_SIZE 2019-07-26 09:14:23 +02:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm/vmscan.c: prevent useless kswapd loops 2019-07-10 09:53:44 +02:00
net 9p/virtio: Add cleanup path in p9_virtio_init 2019-07-26 09:14:25 +02:00
samples samples, bpf: suppress compiler warning 2019-07-14 08:11:04 +02:00
scripts kconfig: fix missing choice values in auto.conf 2019-07-26 09:14:24 +02:00
security selinux: fix empty write to keycreate file 2019-07-26 09:14:07 +02:00
sound ALSA: hda/realtek: apply ALC891 headset fixup to one Dell machine 2019-07-26 09:14:23 +02:00
tools perf tests: Fix record+probe_libc_inet_pton.sh for powerpc64 2019-07-26 09:14:16 +02:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: arm/arm64: vgic: Fix kvm_device leak in vgic_its_destroy 2019-07-14 08:11:10 +02:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS platform/x86: Add Intel AtomISP2 dummy / power-management driver 2019-04-20 09:16:02 +02:00
Makefile Linux 4.19.60 2019-07-21 09:03:18 +02:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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 Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.