Performance oriented customized Linux kernel based on the mainline kernel.
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Jeff Layton 827a746f40 netfs: fix test for whether we can skip read when writing beyond EOF
It's not sufficient to skip reading when the pos is beyond the EOF.
There may be data at the head of the page that we need to fill in
before the write.

Add a new helper function that corrects and clarifies the logic of
when we can skip reads, and have it only zero out the part of the page
that won't have data copied in for the write.

Finally, don't set the page Uptodate after zeroing. It's not up to date
since the write data won't have been copied in yet.

[DH made the following changes:

 - Prefixed the new function with "netfs_".

 - Don't call zero_user_segments() for a full-page write.

 - Altered the beyond-last-page check to avoid a DIV instruction and got
   rid of then-redundant zero-length file check.
]

Fixes: e1b1240c1f ("netfs: Add write_begin helper")
Reported-by: Andrew W Elble <aweits@rit.edu>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: ceph-devel@vger.kernel.org
Link: https://lore.kernel.org/r/20210613233345.113565-1-jlayton@kernel.org/
Link: https://lore.kernel.org/r/162367683365.460125.4467036947364047314.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/162391826758.1173366.11794946719301590013.stgit@warthog.procyon.org.uk/ # v2
2021-06-21 21:24:07 +01:00
arch RISC-V Fixes for 5.13-rc6 2021-06-12 13:57:49 -07:00
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 async_xor: check src_offs is not NULL before updating it 2021-06-10 19:40:14 -07:00
Documentation USB fixes for 5.13-rc6 2021-06-12 12:34:49 -07:00
drivers SCSI fixes on 20210613 2021-06-13 12:25:33 -07:00
fs netfs: fix test for whether we can skip read when writing beyond EOF 2021-06-21 21:24:07 +01:00
include mm: relocate 'write_protect_seq' in struct mm_struct 2021-06-12 13:28:50 -07:00
init pid: take a reference when initializing cad_pid 2021-06-05 08:58:11 -07:00
ipc ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry 2021-05-22 15:09:07 -10:00
kernel Misc fixes: 2021-06-12 11:41:28 -07:00
lib lib: crc64: fix kernel-doc warning 2021-06-05 08:58:12 -07:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm, hugetlb: fix simple resv_huge_pages underflow on UFFDIO_COPY 2021-06-05 08:58:12 -07:00
net Networking fixes for 5.13-rc5, including fixes from bpf, wireless, 2021-06-04 18:25:39 -07:00
samples VFIO fixes for v5.13-rc5 2021-06-03 11:52:24 -07:00
scripts kbuild: Quote OBJCOPY var to avoid a pahole call break the build 2021-05-27 11:32:56 -07:00
security trusted-keys: match tpm_get_ops on all return paths 2021-05-12 22:36:37 +03:00
sound sound fixes for 5.13-rc6 2021-06-11 10:47:10 -07:00
tools perf tools fixes for v5.13: 5th batch 2021-06-13 12:41:47 -07:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt KVM: VMX: update vcpu posted-interrupt descriptor when assigning device 2021-05-27 07:58:23 -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: use private address for Michel Lespinasse 2021-06-05 08:58:12 -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 USB fixes for 5.13-rc6 2021-06-12 12:34:49 -07:00
Makefile Linux 5.13-rc6 2021-06-13 14:43:10 -07:00
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.