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Filename Latest commit message Latest commit date
Coly Li dc7292a5bc bcache: use (REQ_META|REQ_PRIO) to indicate bio for metadata
In 'commit 752f66a75a ("bcache: use REQ_PRIO to indicate bio for
metadata")' REQ_META is replaced by REQ_PRIO to indicate metadata bio.
This assumption is not always correct, e.g. XFS uses REQ_META to mark
metadata bio other than REQ_PRIO. This is why Nix noticed that bcache
does not cache metadata for XFS after the above commit.

Thanks to Dave Chinner, he explains the difference between REQ_META and
REQ_PRIO from view of file system developer. Here I quote part of his
explanation from mailing list,
   REQ_META is used for metadata. REQ_PRIO is used to communicate to
   the lower layers that the submitter considers this IO to be more
   important that non REQ_PRIO IO and so dispatch should be expedited.

   IOWs, if the filesystem considers metadata IO to be more important
   that user data IO, then it will use REQ_PRIO | REQ_META rather than
   just REQ_META.

Then it seems bios with REQ_META or REQ_PRIO should both be cached for
performance optimation, because they are all probably low I/O latency
demand by upper layer (e.g. file system).

So in this patch, when we want to decide whether to bypass the cache,
REQ_META and REQ_PRIO are both checked. Then both metadata and
high priority I/O requests will be handled properly.

Reported-by: Nix <nix@esperi.org.uk>
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Andre Noll <maan@tuebingen.mpg.de>
Tested-by: Nix <nix@esperi.org.uk>
Cc: stable@vger.kernel.org
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-09 07:18:33 -07:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-01-27 12:02:00 -08:00
block block: avoid setting nr_requests to current value 2019-02-08 12:43:25 -07:00
certs
crypto crypto: sm3 - fix undefined shift by >= width of value 2019-01-10 21:37:32 +08:00
Documentation drm fixes. msm, sun4i, amdgpu, i915 gvt 2019-01-25 12:19:10 +13:00
drivers bcache: use (REQ_META|REQ_PRIO) to indicate bio for metadata 2019-02-09 07:18:33 -07:00
firmware kbuild: change filechk to surround the given command with { } 2019-01-06 09:46:51 +09:00
fs a set of small smb3 fixes, some fixing various crediting issues discovered during xfstest runs, five for stable 2019-01-26 15:38:22 -08:00
include Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-01-27 11:52:50 -08:00
init kbuild: Disable LD_DEAD_CODE_DATA_ELIMINATION with ftrace & GCC <= 4.7 2019-01-14 10:37:09 +09:00
ipc
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-01-27 11:55:06 -08:00
lib XArray updates for 5.0-rc3 2019-01-22 17:08:30 +13:00
LICENSES
mm for-linus-20190125 2019-01-26 12:42:41 -08:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-01-27 08:59:12 -08:00
samples samples/bpf: workaround clang asm goto compilation errors 2019-01-15 20:57:30 +01:00
scripts Bug fixes for gcc-plugins 2019-01-21 13:07:03 +13:00
security Merge branch 'fixes-v5.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-01-17 16:54:58 +12:00
sound sound fixes for 5.0-rc4 2019-01-25 05:55:26 +13:00
tools Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-01-27 12:02:00 -08:00
usr
virt KVM: validate userspace input in kvm_clear_dirty_log_protect() 2019-01-11 18:38:07 +01:00
.clang-format clang-format: Update .clang-format with the latest for_each macro list 2019-01-19 19:26:06 +01:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild kbuild: use assignment instead of define ... endef for filechk_* rules 2019-01-06 10:22:35 +09:00
Kconfig
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-01-27 08:59:12 -08:00
Makefile Linux 5.0-rc4 2019-01-27 15:18:05 -08:00
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.