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Qu Wenruo 23f3aff83a btrfs: don't clear page extent mapped if we're not invalidating the full page 
[ Upstream commit bcd77455d5 ]

[BUG]
With current btrfs subpage rw support, the following script can lead to
fs hang:

  $ mkfs.btrfs -f -s 4k $dev
  $ mount $dev -o nospace_cache $mnt
  $ fsstress -w -n 100 -p 1 -s 1608140256 -v -d $mnt

The fs will hang at btrfs_start_ordered_extent().

[CAUSE]
In above test case, btrfs_invalidate() will be called with the following
parameters:

  offset = 0 length = 53248 page dirty = 1 subpage dirty bitmap = 0x2000

Since @offset is 0, btrfs_invalidate() will try to invalidate the full
page, and finally call clear_page_extent_mapped() which will detach
subpage structure from the page.

And since the page no longer has subpage structure, the subpage dirty
bitmap will be cleared, preventing the dirty range from being written
back, thus no way to wake up the ordered extent.

[FIX]
Just follow other filesystems, only to invalidate the page if the range
covers the full page.

There are cases like truncate_setsize() which can call
btrfs_invalidatepage() with offset == 0 and length != 0 for the last
page of an inode.

Although the old code will still try to invalidate the full page, we are
still safe to just wait for ordered extent to finish.
So it shouldn't cause extra problems.

Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> # [ppc64]
Tested-by: Anand Jain <anand.jain@oracle.com> # [aarch64]
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2021-07-14 17:06:28 +02:00
arch KVM: PPC: Book3S HV: Fix TLB management on SMT8 POWER9 and POWER10 processors 2021-07-14 17:06:27 +02:00
block block-5.13-2021-05-22 2021-05-22 07:40:34 -10:00
certs Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 17:06:26 +02:00
Documentation hwmon: (max31790) Fix pwmX_enable attributes 2021-07-14 17:06:27 +02:00
drivers drivers/perf: fix the missed ida_simple_remove() in ddr_perf_probe() 2021-07-14 17:06:27 +02:00
fs btrfs: don't clear page extent mapped if we're not invalidating the full page 2021-07-14 17:06:28 +02:00
include crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 17:06:26 +02:00
init sched/core: Initialize the idle task with preemption disabled 2021-07-14 17:06:21 +02:00
ipc ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry 2021-05-22 15:09:07 -10:00
kernel sched/fair: Take thermal pressure into account while estimating energy 2021-07-14 17:06:27 +02:00
lib seq_buf: Make trace_seq_putmem_hex() support data longer than 8 2021-07-14 17:06:17 +02:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm/gup: fix try_grab_compound_head() race with split_huge_page() 2021-07-14 17:06:12 +02:00
net SUNRPC: Should wake up the privileged task firstly. 2021-07-14 17:06:11 +02:00
samples VFIO fixes for v5.13-rc5 2021-06-03 11:52:24 -07:00
scripts Makefile: fix GDB warning with CONFIG_RELR 2021-07-14 17:06:25 +02:00
security ima: Don't remove security.ima if file must not be appraised 2021-07-14 17:06:24 +02:00
sound ALSA: hda/realtek: fix mute led of the HP Pavilion 15-eh1xxx series 2021-07-14 17:06:04 +02:00
tools selftests/resctrl: Fix incorrect parsing of option "-t" 2021-07-14 17:06:16 +02:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt KVM: do not allow mapping valid but non-reference-counted pages 2021-06-24 11:55:11 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Marek's other e-mail address and identity without diacritics 2021-06-24 19:40:54 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: move Murali Karicheri to credits 2021-04-29 15:47:30 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2021-06-25 11:05:03 -07:00
Makefile Makefile: fix GDB warning with CONFIG_RELR 2021-07-14 17:06:25 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

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.