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Josef Bacik f7313de46e btrfs: fix incorrect updating of log root tree
commit 4203e96894 upstream.

We've historically had reports of being unable to mount file systems
because the tree log root couldn't be read.  Usually this is the "parent
transid failure", but could be any of the related errors, including
"fsid mismatch" or "bad tree block", depending on which block got
allocated.

The modification of the individual log root items are serialized on the
per-log root root_mutex.  This means that any modification to the
per-subvol log root_item is completely protected.

However we update the root item in the log root tree outside of the log
root tree log_mutex.  We do this in order to allow multiple subvolumes
to be updated in each log transaction.

This is problematic however because when we are writing the log root
tree out we update the super block with the _current_ log root node
information.  Since these two operations happen independently of each
other, you can end up updating the log root tree in between writing out
the dirty blocks and setting the super block to point at the current
root.

This means we'll point at the new root node that hasn't been written
out, instead of the one we should be pointing at.  Thus whatever garbage
or old block we end up pointing at complains when we mount the file
system later and try to replay the log.

Fix this by copying the log's root item into a local root item copy.
Then once we're safely under the log_root_tree->log_mutex we update the
root item in the log_root_tree.  This way we do not modify the
log_root_tree while we're committing it, fixing the problem.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Chris Mason <clm@fb.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-17 13:45:26 -07:00
arch USB: rio500: Remove Rio 500 kernel driver 2019-10-17 13:44:47 -07:00
block blk-wbt: fix performance regression in wbt scale_up/scale_down 2019-10-17 13:45:16 -07:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: skcipher - Unmap pages after an external error 2019-10-11 18:20:52 +02:00
Documentation USB: rio500: Remove Rio 500 kernel driver 2019-10-17 13:44:47 -07:00
drivers iio: adc: stm32-adc: fix a race when using several adcs with dma and irq 2019-10-17 13:45:23 -07:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs btrfs: fix incorrect updating of log root tree 2019-10-17 13:45:26 -07:00
include cfg80211: Use const more consistently in for_each_element macros 2019-10-11 18:21:43 +02:00
init initramfs: don't free a non-existent initrd 2019-10-01 08:26:09 +02:00
ipc ipc/mqueue.c: only perform resource calculation if user valid 2019-08-06 19:06:52 +02:00
kernel kernel/sysctl.c: do not override max_threads provided by userspace 2019-10-17 13:45:19 -07:00
lib kmemleak: increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE default to 16K 2019-10-07 18:57:17 +02:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm/vmpressure.c: fix a signedness bug in vmpressure_register_event() 2019-10-17 13:45:19 -07:00
net nl80211: validate beacon head 2019-10-11 18:21:44 +02:00
samples samples, bpf: suppress compiler warning 2019-07-14 08:11:04 +02:00
scripts randstruct: Check member structs in is_pure_ops_struct() 2019-10-05 13:10:02 +02:00
security ima: fix freeing ongoing ahash_request 2019-10-11 18:21:11 +02:00
sound ASoC: sgtl5000: Improve VAG power and mute control 2019-10-11 18:20:47 +02:00
tools perf inject jit: Fix JIT_CODE_MOVE filename 2019-10-17 13:45:15 -07:00
usr kbuild: clean compressed initramfs image 2019-10-07 18:57:16 +02:00
virt KVM: coalesced_mmio: add bounds checking 2019-09-21 07:16:44 +02:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 USB: rio500: Remove Rio 500 kernel driver 2019-10-17 13:44:47 -07:00
Makefile Linux 4.19.79 2019-10-11 18:21:44 +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.