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Boris Burkov 2b5463fcbd btrfs: hold block group refcount during async discard
Async discard does not acquire the block group reference count while it
holds a reference on the discard list. This is generally OK, as the
paths which destroy block groups tend to try to synchronize on
cancelling async discard work. However, relying on cancelling work
requires careful analysis to be sure it is safe from races with
unpinning scheduling more work.

While I am unable to find a race with unpinning in the current code for
either the unused bgs or relocation paths, I believe we have one in an
older version of auto relocation in a Meta internal build. This suggests
that this is in fact an error prone model, and could be fragile to
future changes to these bg deletion paths.

To make this ownership more clear, add a refcount for async discard. If
work is queued for a block group, its refcount should be incremented,
and when work is completed or canceled, it should be decremented.

CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-02-15 19:38:50 +01:00
arch powerpc fixes for 6.2 #5 2023-02-12 11:08:15 -08:00
block block-6.2-2023-02-03 2023-02-03 11:35:42 -08:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-01-31 17:53:01 +09:00
crypto This update includes the following changes: 2022-12-14 12:31:09 -08:00
Documentation Networking fixes for 6.2-rc8, including fixes from can and 2023-02-09 09:17:38 -08:00
drivers USB fixes for 6.2-rc8 2023-02-12 11:18:57 -08:00
fs btrfs: hold block group refcount during async discard 2023-02-15 19:38:50 +01:00
include btrfs: introduce size class to block group allocator 2023-02-13 17:50:34 +01:00
init Kbuild fixes for v6.2 (3rd) 2023-01-21 10:56:37 -08:00
io_uring io_uring: always prep_async for drain requests 2023-01-27 06:29:29 -07:00
ipc Non-MM patches for 6.2-rc1. 2022-12-12 17:28:58 -08:00
kernel tracing: Fix showing of TASK_COMM_LEN instead of its value 2023-02-12 13:52:17 -08:00
lib - Lock the proper critical section when dealing with perf event context 2023-02-05 11:03:56 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm Fix page corruption caused by racy check in __free_pages 2023-02-12 10:30:05 -08:00
net rds: rds_rm_zerocopy_callback() use list_first_entry() 2023-02-09 10:37:26 +01:00
rust rust: print: avoid evaluating arguments in pr_* macros in unsafe blocks 2023-01-16 00:54:35 +01:00
samples ftrace: Export ftrace_free_filter() to modules 2023-01-24 11:20:58 -05:00
scripts Kbuild fixes for v6.2 (4th) 2023-02-04 11:30:23 -08:00
security tomoyo: Update website link 2023-01-13 23:11:38 +09:00
sound sound fixes for 6.2-rc8 2023-02-10 08:37:48 -08:00
tools Revert "mm: Always release pages to the buddy allocator in memblock_free_late()." 2023-02-11 10:51:45 -08:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt VFIO fixes for v6.2-rc6 2023-01-23 11:56:07 -08:00
.clang-format iommufd for 6.2 2022-12-14 09:15:43 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore *.rpm 2022-12-30 17:22:14 +09:00
.mailmap 25 hotfixes, mainly for MM. 13 are cc:stable. 2023-02-03 10:01:57 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: update SCTP maintainers 2023-02-02 11:35:33 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: Add myself as maintainer for arch/sh (SUPERH) 2023-02-12 13:57:09 -08:00
Makefile Linux 6.2-rc8 2023-02-12 14:10:17 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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.

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.