github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-08-01 12:11:59 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph
Linux kernel source tree
935,080 Commits 1 Branch 940 Tags 24 GiB
C 96.9%
Assembly 0.9%
Rust 0.6%
Shell 0.6%
Python 0.5%
Other 0.3%
8c8648dd1f
Go to file
Filipe Manana 8c8648dd1f btrfs: only commit the delayed inode when doing a full fsync 
Commit 2c2c452b0c ("Btrfs: fix fsync when extend references are added
to an inode") forced a commit of the delayed inode when logging an inode
in order to ensure we would end up logging the inode item during a full
fsync. By committing the delayed inode, we updated the inode item in the
fs/subvolume tree and then later when copying items from leafs modified in
the current transaction into the log tree (with copy_inode_items_to_log())
we ended up copying the inode item from the fs/subvolume tree into the log
tree. Logging an up to date version of the inode item is required to make
sure at log replay time we get the link count fixup triggered among other
things (replay xattr deletes, etc). The test case generic/040 from fstests
exercises the bug which that commit fixed.

However for a fast fsync we don't need to commit the delayed inode because
we always log an up to date version of the inode item based on the struct
btrfs_inode we have in-memory. We started doing this for fast fsyncs since
commit e4545de5b0 ("Btrfs: fix fsync data loss after append write").

So just stop committing the delayed inode if we are doing a fast fsync,
we are only wasting time and adding contention on fs/subvolume tree.

This patch is part of a series that has the following patches:

1/4 btrfs: only commit the delayed inode when doing a full fsync
2/4 btrfs: only commit delayed items at fsync if we are logging a directory
3/4 btrfs: stop incremening log_batch for the log root tree when syncing log
4/4 btrfs: remove no longer needed use of log_writers for the log root tree

After the entire patchset applied I saw about 12% decrease on max latency
reported by dbench. The test was done on a qemu vm, with 8 cores, 16Gb of
ram, using kvm and using a raw NVMe device directly (no intermediary fs on
the host). The test was invoked like the following:

  mkfs.btrfs -f /dev/sdk
  mount -o ssd -o nospace_cache /dev/sdk /mnt/sdk
  dbench -D /mnt/sdk -t 300 8
  umount /mnt/dsk

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:38 +02:00
arch Merge branch 'parisc-5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux into master 2020-07-26 12:14:46 -07:00
block block-5.8-2020-07-10 2020-07-10 09:55:46 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto keys: asymmetric: fix error return code in software_key_query() 2020-07-15 15:49:04 -07:00
Documentation Char/misc driver fixes for 5.8-rc7 2020-07-26 09:33:25 -07:00
drivers Char/misc driver fixes for 5.8-rc7 2020-07-26 09:33:25 -07:00
fs btrfs: only commit the delayed inode when doing a full fsync 2020-07-27 12:55:38 +02:00
include btrfs: use __u16 for the return value of btrfs_qgroup_level() 2020-07-27 12:55:37 +02:00
init kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang 2020-07-02 00:57:45 +09:00
ipc mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
kernel Fix a interaction/regression between uprobes based shared library tracing & GDB. 2020-07-25 13:55:38 -07:00
lib RISC-V Fixes for 5.8-rc5 (ideally) 2020-07-11 19:22:46 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm khugepaged: fix null-pointer dereference due to race 2020-07-24 12:42:41 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net into master 2020-07-25 11:50:59 -07:00
samples samples/vfs: avoid warning in statx override 2020-07-03 16:15:25 -07:00
scripts Kbuild fixes for v5.8 (3rd) 2020-07-26 13:46:57 -07:00
security integrity/ima: switch to using __kernel_read 2020-07-08 08:27:57 +02:00
sound sound fixes for 5.8-rc7 2020-07-21 08:06:45 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net into master 2020-07-25 11:50:59 -07:00
usr bpfilter: match bit size of bpfilter_umh to that of the kernel 2020-05-17 18:52:01 +09:00
virt kvm: use more precise cast and do not drop __user 2020-07-02 05:39:31 -04:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig
.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: Do not track defconfig from make savedefconfig 2020-07-05 16:15:46 +09:00
.mailmap mailmap: add entry for Mike Rapoport 2020-07-24 12:42:41 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS mailmap: change email for Ricardo Ribalda 2020-05-25 18:59:59 -06:00
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' into master (patches from Andrew) 2020-07-24 14:24:35 -07:00
Makefile Linux 5.8-rc7 2020-07-26 14:14:06 -07:00
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.