From: Patrick Steinhardt <ps@pks.im>
To: Neeraj Singh via GitGitGadget <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, rsbecker@nexbridge.com,
bagasdotme@gmail.com, newren@gmail.com, avarab@gmail.com,
nksingh85@gmail.com, "Neeraj K. Singh" <neerajsi@microsoft.com>
Subject: Re: [PATCH v2 1/3] core.fsyncmethod: add writeout-only mode
Date: Tue, 7 Dec 2021 12:44:38 +0100 [thread overview]
Message-ID: <Ya9JJlItvDJCLHqj@ncase> (raw)
In-Reply-To: <e79522cbdd4feb45b062b75225475f34039d1866.1638845211.git.gitgitgadget@gmail.com>
[-- Attachment #1: Type: text/plain, Size: 4326 bytes --]
On Tue, Dec 07, 2021 at 02:46:49AM +0000, Neeraj Singh via GitGitGadget wrote:
> From: Neeraj Singh <neerajsi@microsoft.com>
[snip]
> --- a/compat/mingw.h
> +++ b/compat/mingw.h
> @@ -329,6 +329,9 @@ int mingw_getpagesize(void);
> #define getpagesize mingw_getpagesize
> #endif
>
> +int win32_fsync_no_flush(int fd);
> +#define fsync_no_flush win32_fsync_no_flush
> +
> struct rlimit {
> unsigned int rlim_cur;
> };
> diff --git a/compat/win32/flush.c b/compat/win32/flush.c
> new file mode 100644
> index 00000000000..75324c24ee7
> --- /dev/null
> +++ b/compat/win32/flush.c
> @@ -0,0 +1,28 @@
> +#include "../../git-compat-util.h"
> +#include <winternl.h>
> +#include "lazyload.h"
> +
> +int win32_fsync_no_flush(int fd)
> +{
> + IO_STATUS_BLOCK io_status;
> +
> +#define FLUSH_FLAGS_FILE_DATA_ONLY 1
> +
> + DECLARE_PROC_ADDR(ntdll.dll, NTSTATUS, NtFlushBuffersFileEx,
> + HANDLE FileHandle, ULONG Flags, PVOID Parameters, ULONG ParameterSize,
> + PIO_STATUS_BLOCK IoStatusBlock);
> +
> + if (!INIT_PROC_ADDR(NtFlushBuffersFileEx)) {
> + errno = ENOSYS;
> + return -1;
> + }
I'm wondering whether it would make sense to fall back to fsync(3P) in
case we cannot use writeout-only, but I see that were doing essentially
that in `fsync_or_die()`. There is no indicator to the user though that
writeout-only doesn't work -- do we want to print a one-time warning?
> + memset(&io_status, 0, sizeof(io_status));
> + if (NtFlushBuffersFileEx((HANDLE)_get_osfhandle(fd), FLUSH_FLAGS_FILE_DATA_ONLY,
> + NULL, 0, &io_status)) {
> + errno = EINVAL;
> + return -1;
> + }
> +
> + return 0;
> +}
[snip]
> diff --git a/wrapper.c b/wrapper.c
> index 36e12119d76..1c5f2c87791 100644
> --- a/wrapper.c
> +++ b/wrapper.c
> @@ -546,6 +546,62 @@ int xmkstemp_mode(char *filename_template, int mode)
> return fd;
> }
>
> +int git_fsync(int fd, enum fsync_action action)
> +{
> + switch (action) {
> + case FSYNC_WRITEOUT_ONLY:
> +
> +#ifdef __APPLE__
> + /*
> + * on macOS, fsync just causes filesystem cache writeback but does not
> + * flush hardware caches.
> + */
> + return fsync(fd);
Below we're looping around `EINTR` -- are Apple systems never returning
it?
Patrick
> +#endif
> +
> +#ifdef HAVE_SYNC_FILE_RANGE
> + /*
> + * On linux 2.6.17 and above, sync_file_range is the way to issue
> + * a writeback without a hardware flush. An offset of 0 and size of 0
> + * indicates writeout of the entire file and the wait flags ensure that all
> + * dirty data is written to the disk (potentially in a disk-side cache)
> + * before we continue.
> + */
> +
> + return sync_file_range(fd, 0, 0, SYNC_FILE_RANGE_WAIT_BEFORE |
> + SYNC_FILE_RANGE_WRITE |
> + SYNC_FILE_RANGE_WAIT_AFTER);
> +#endif
> +
> +#ifdef fsync_no_flush
> + return fsync_no_flush(fd);
> +#endif
> +
> + errno = ENOSYS;
> + return -1;
> +
> + case FSYNC_HARDWARE_FLUSH:
> + /*
> + * On some platforms fsync may return EINTR. Try again in this
> + * case, since callers asking for a hardware flush may die if
> + * this function returns an error.
> + */
> + for (;;) {
> + int err;
> +#ifdef __APPLE__
> + err = fcntl(fd, F_FULLFSYNC);
> +#else
> + err = fsync(fd);
> +#endif
> + if (err >= 0 || errno != EINTR)
> + return err;
> + }
> +
> + default:
> + BUG("unexpected git_fsync(%d) call", action);
> + }
> +}
> +
> static int warn_if_unremovable(const char *op, const char *file, int rc)
> {
> int err;
> diff --git a/write-or-die.c b/write-or-die.c
> index 0b1ec8190b6..0702acdd5e8 100644
> --- a/write-or-die.c
> +++ b/write-or-die.c
> @@ -57,10 +57,12 @@ void fprintf_or_die(FILE *f, const char *fmt, ...)
>
> void fsync_or_die(int fd, const char *msg)
> {
> - while (fsync(fd) < 0) {
> - if (errno != EINTR)
> - die_errno("fsync error on '%s'", msg);
> - }
> + if (fsync_method == FSYNC_METHOD_WRITEOUT_ONLY &&
> + git_fsync(fd, FSYNC_WRITEOUT_ONLY) >= 0)
> + return;
> +
> + if (git_fsync(fd, FSYNC_HARDWARE_FLUSH) < 0)
> + die_errno("fsync error on '%s'", msg);
> }
>
> void write_or_die(int fd, const void *buf, size_t count)
> --
> gitgitgadget
>
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
next prev parent reply other threads:[~2021-12-07 11:45 UTC|newest]
Thread overview: 122+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-04 3:28 [PATCH 0/2] A design for future-proofing fsync() configuration Neeraj K. Singh via GitGitGadget
2021-12-04 3:28 ` [PATCH 1/2] fsync: add writeout-only mode for fsyncing repo data Neeraj Singh via GitGitGadget
2021-12-06 7:54 ` Neeraj Singh
2021-12-04 3:28 ` [PATCH 2/2] core.fsync: introduce granular fsync control Neeraj Singh via GitGitGadget
2021-12-07 2:46 ` [PATCH v2 0/3] A design for future-proofing fsync() configuration Neeraj K. Singh via GitGitGadget
2021-12-07 2:46 ` [PATCH v2 1/3] core.fsyncmethod: add writeout-only mode Neeraj Singh via GitGitGadget
2021-12-07 11:44 ` Patrick Steinhardt [this message]
2021-12-07 12:14 ` Ævar Arnfjörð Bjarmason
2021-12-07 23:29 ` Neeraj Singh
2021-12-07 12:18 ` Ævar Arnfjörð Bjarmason
2021-12-07 23:58 ` Neeraj Singh
2021-12-07 2:46 ` [PATCH v2 2/3] core.fsync: introduce granular fsync control Neeraj Singh via GitGitGadget
2021-12-07 11:53 ` Patrick Steinhardt
2021-12-07 20:46 ` Neeraj Singh
2021-12-07 12:29 ` Ævar Arnfjörð Bjarmason
2021-12-07 21:44 ` Neeraj Singh
2021-12-08 10:05 ` Ævar Arnfjörð Bjarmason
2021-12-09 0:14 ` Neeraj Singh
2021-12-09 0:44 ` Junio C Hamano
2021-12-09 4:08 ` Ævar Arnfjörð Bjarmason
2021-12-09 6:18 ` Neeraj Singh
2022-01-18 23:50 ` Neeraj Singh
2022-01-19 15:28 ` Ævar Arnfjörð Bjarmason
2022-01-19 14:52 ` Ævar Arnfjörð Bjarmason
2022-01-28 1:28 ` Neeraj Singh
2021-12-07 2:46 ` [PATCH v2 3/3] core.fsync: new option to harden the index Neeraj Singh via GitGitGadget
2021-12-07 11:56 ` [PATCH v2 0/3] A design for future-proofing fsync() configuration Patrick Steinhardt
2021-12-08 0:44 ` Neeraj Singh
2021-12-09 0:57 ` [PATCH v3 0/4] " Neeraj K. Singh via GitGitGadget
2021-12-09 0:57 ` [PATCH v3 1/4] core.fsyncmethod: add writeout-only mode Neeraj Singh via GitGitGadget
2021-12-09 0:57 ` [PATCH v3 2/4] core.fsync: introduce granular fsync control Neeraj Singh via GitGitGadget
2021-12-09 0:57 ` [PATCH v3 3/4] core.fsync: new option to harden the index Neeraj Singh via GitGitGadget
2021-12-09 0:57 ` [PATCH v3 4/4] core.fsync: add a `derived-metadata` aggregate option Neeraj Singh via GitGitGadget
2022-01-08 1:13 ` [PATCH v3 0/4] A design for future-proofing fsync() configuration Neeraj Singh
2022-01-09 0:55 ` rsbecker
2022-01-10 19:00 ` Neeraj Singh
2022-02-01 3:33 ` [PATCH v4 " Neeraj K. Singh via GitGitGadget
2022-02-01 3:33 ` [PATCH v4 1/4] core.fsyncmethod: add writeout-only mode Neeraj Singh via GitGitGadget
2022-02-01 3:33 ` [PATCH v4 2/4] core.fsync: introduce granular fsync control Neeraj Singh via GitGitGadget
2022-02-02 0:51 ` Junio C Hamano
2022-02-02 1:42 ` Junio C Hamano
2022-02-11 21:18 ` Neeraj Singh
2022-02-11 22:19 ` Junio C Hamano
2022-02-11 23:04 ` Neeraj Singh
2022-02-11 23:15 ` Junio C Hamano
2022-02-12 0:39 ` rsbecker
2022-02-14 7:04 ` Patrick Steinhardt
2022-02-14 17:17 ` Junio C Hamano
2022-03-09 13:42 ` Patrick Steinhardt
2022-03-09 18:50 ` Ævar Arnfjörð Bjarmason
2022-03-09 20:03 ` Junio C Hamano
2022-03-10 12:33 ` Patrick Steinhardt
2022-03-10 17:15 ` Junio C Hamano
2022-03-09 20:05 ` Neeraj Singh
2022-02-11 20:38 ` Neeraj Singh
2022-02-01 3:33 ` [PATCH v4 3/4] core.fsync: new option to harden the index Neeraj Singh via GitGitGadget
2022-02-01 3:33 ` [PATCH v4 4/4] core.fsync: add a `derived-metadata` aggregate option Neeraj Singh via GitGitGadget
2022-03-09 23:03 ` [PATCH v5 0/5] A design for future-proofing fsync() configuration Neeraj K. Singh via GitGitGadget
2022-03-09 23:03 ` [PATCH v5 1/5] wrapper: move inclusion of CSPRNG headers the wrapper.c file Neeraj Singh via GitGitGadget
2022-03-09 23:29 ` Junio C Hamano
2022-03-10 1:21 ` Neeraj Singh
2022-03-10 1:26 ` brian m. carlson
2022-03-10 1:56 ` Neeraj Singh
2022-03-09 23:03 ` [PATCH v5 2/5] core.fsyncmethod: add writeout-only mode Neeraj Singh via GitGitGadget
2022-03-09 23:48 ` Junio C Hamano
2022-03-09 23:03 ` [PATCH v5 3/5] core.fsync: introduce granular fsync control Neeraj Singh via GitGitGadget
2022-03-10 0:21 ` Junio C Hamano
2022-03-10 2:53 ` Neeraj Singh
2022-03-10 7:19 ` Junio C Hamano
2022-03-10 18:38 ` Neeraj Singh
2022-03-10 18:44 ` Junio C Hamano
2022-03-10 19:57 ` Junio C Hamano
2022-03-10 20:25 ` Neeraj Singh
2022-03-10 21:17 ` Junio C Hamano
2022-03-10 13:11 ` Johannes Schindelin
2022-03-10 17:18 ` Junio C Hamano
2022-03-09 23:03 ` [PATCH v5 4/5] core.fsync: new option to harden the index Neeraj Singh via GitGitGadget
2022-03-09 23:03 ` [PATCH v5 5/5] core.fsync: documentation and user-friendly aggregate options Neeraj Singh via GitGitGadget
2022-03-10 9:53 ` Future-proofed syncing of refs Patrick Steinhardt
2022-03-10 9:53 ` [PATCH 6/8] core.fsync: add `fsync_component()` wrapper which doesn't die Patrick Steinhardt
2022-03-10 17:34 ` Junio C Hamano
2022-03-10 18:40 ` Neeraj Singh
2022-03-10 9:53 ` [PATCH 7/8] core.fsync: new option to harden loose references Patrick Steinhardt
2022-03-10 18:25 ` Junio C Hamano
2022-03-10 19:03 ` Neeraj Singh
2022-03-10 22:54 ` Neeraj Singh
2022-03-11 6:40 ` Junio C Hamano
2022-03-11 9:15 ` Patrick Steinhardt
2022-03-11 9:36 ` Ævar Arnfjörð Bjarmason
2022-03-10 9:53 ` [PATCH 8/8] core.fsync: new option to harden packed references Patrick Steinhardt
2022-03-10 18:28 ` Junio C Hamano
2022-03-11 9:10 ` Patrick Steinhardt
2022-03-10 22:43 ` [PATCH v6 0/6] A design for future-proofing fsync() configuration Neeraj K. Singh via GitGitGadget
2022-03-10 22:43 ` [PATCH v6 1/6] wrapper: make inclusion of Windows csprng header tightly scoped Neeraj Singh via GitGitGadget
2022-03-10 22:43 ` [PATCH v6 2/6] core.fsyncmethod: add writeout-only mode Neeraj Singh via GitGitGadget
2022-03-10 22:43 ` [PATCH v6 3/6] core.fsync: introduce granular fsync control infrastructure Neeraj Singh via GitGitGadget
2022-03-10 22:43 ` [PATCH v6 4/6] core.fsync: add configuration parsing Neeraj Singh via GitGitGadget
2022-03-28 11:06 ` Jiang Xin
2022-03-28 19:45 ` Neeraj Singh
2022-03-10 22:43 ` [PATCH v6 5/6] core.fsync: new option to harden the index Neeraj Singh via GitGitGadget
2022-03-10 22:43 ` [PATCH v6 6/6] core.fsync: documentation and user-friendly aggregate options Neeraj Singh via GitGitGadget
2022-03-15 19:12 ` [PATCH v7] " Neeraj Singh
2022-03-15 19:32 ` Junio C Hamano
2022-03-15 19:56 ` Neeraj Singh
2022-03-23 14:20 ` do we have too much fsync() configuration in 'next'? (was: [PATCH v7] core.fsync: documentation and user-friendly aggregate options) Ævar Arnfjörð Bjarmason
2022-03-25 21:24 ` Neeraj Singh
2022-03-26 0:24 ` Ævar Arnfjörð Bjarmason
2022-03-26 1:23 ` do we have too much fsync() configuration in 'next'? Junio C Hamano
2022-03-26 1:25 ` do we have too much fsync() configuration in 'next'? (was: [PATCH v7] core.fsync: documentation and user-friendly aggregate options) Neeraj Singh
2022-03-26 15:31 ` Ævar Arnfjörð Bjarmason
2022-03-27 5:27 ` Neeraj Singh
2022-03-27 12:43 ` Ævar Arnfjörð Bjarmason
2022-03-28 10:56 ` Patrick Steinhardt
2022-03-28 11:25 ` Ævar Arnfjörð Bjarmason
2022-03-28 19:56 ` Neeraj Singh
2022-03-30 16:59 ` Neeraj Singh
2022-03-10 23:34 ` [PATCH v6 0/6] A design for future-proofing fsync() configuration Junio C Hamano
2022-03-11 0:03 ` Neeraj Singh
2022-03-11 18:50 ` Neeraj Singh
2022-03-13 23:50 ` Junio C Hamano
2022-03-11 9:58 ` [PATCH v2] core.fsync: new option to harden references Patrick Steinhardt
2022-03-25 6:11 ` SZEDER Gábor
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Ya9JJlItvDJCLHqj@ncase \
--to=ps@pks.im \
--cc=avarab@gmail.com \
--cc=bagasdotme@gmail.com \
--cc=git@vger.kernel.org \
--cc=gitgitgadget@gmail.com \
--cc=neerajsi@microsoft.com \
--cc=newren@gmail.com \
--cc=nksingh85@gmail.com \
--cc=rsbecker@nexbridge.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).