Package: coreutils;
Reported by: Giuseppe Scrivano <gscrivan <at> redhat.com>
Date: Sun, 25 Jan 2015 03:06:02 UTC
Severity: normal
Tags: patch
Done: Assaf Gordon <assafgordon <at> gmail.com>
Bug is archived. No further changes may be made.
View this message in rfc822 format
From: Giuseppe Scrivano <gscrivan <at> redhat.com> To: Pádraig Brady <P <at> draigbrady.com> Cc: Bernhard Voelker <mail <at> bernhard-voelker.de>, Eric Blake <eblake <at> redhat.com>, 19681 <at> debbugs.gnu.org, Paul Eggert <eggert <at> cs.ucla.edu> Subject: bug#19681: [PATCH] sync: use syncfs(2) if any argument is specified Date: Tue, 27 Jan 2015 11:48:44 +0100
Pádraig Brady <P <at> draigbrady.com> writes:
> thanks!
> Pádraig.
Thanks for the review, I've amended the changes you suggested:
From b2babc9838b52892e2cdc46bc4590fa852daa0eb Mon Sep 17 00:00:00 2001
From: Giuseppe Scrivano <gscrivan <at> redhat.com>
Date: Sun, 25 Jan 2015 01:33:45 +0100
Subject: [PATCH] sync: add support for fsync(2), fdatasync(2) and syncfs(2)
* AUTHORS: Add myself to sync's authors.
* NEWS: Mention the new feature.
* m4/jm-macros.m4 (coreutils_MACROS): Check for syncfs.
* man/sync.x: Add references to syncfs, fsync and fdatasync.
* doc/coreutils.texi (sync invocation): Document the new feature.
* src/sync.c: Include "quote.h".
(AUTHORS): Include myself.
(MODE_FILE, MODE_DATA, MODE_FILE_SYSTEM, MODE_SYNC): New enum values.
(long_options): Define.
(sync_arg): New function.
(usage): Describe that arguments are now accepted.
(main): Add arguments parsing and add support for fsync(2),
fdatasync(2) and syncfs(2).
---
AUTHORS | 2 +-
NEWS | 3 +
doc/coreutils.texi | 20 ++++++-
m4/jm-macros.m4 | 1 +
man/sync.x | 2 +-
src/sync.c | 157 +++++++++++++++++++++++++++++++++++++++++++++++++----
6 files changed, 170 insertions(+), 15 deletions(-)
diff --git a/AUTHORS b/AUTHORS
index 0296830..64c11d7 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -83,7 +83,7 @@ stat: Michael Meskes
stdbuf: Pádraig Brady
stty: David MacKenzie
sum: Kayvan Aghaiepour, David MacKenzie
-sync: Jim Meyering
+sync: Jim Meyering, Giuseppe Scrivano
tac: Jay Lepreau, David MacKenzie
tail: Paul Rubin, David MacKenzie, Ian Lance Taylor, Jim Meyering
tee: Mike Parker, Richard M. Stallman, David MacKenzie
diff --git a/NEWS b/NEWS
index e0a2893..3d4190b 100644
--- a/NEWS
+++ b/NEWS
@@ -48,6 +48,9 @@ GNU coreutils NEWS -*- outline -*-
split accepts a new --separator option to select a record separator character
other than the default newline character.
+ sync no longer ignores arguments and it uses fsync(2), fdatasync(2)
+ and syncfs(2) synchronization in addition to sync(2).
+
** Changes in behavior
df no longer suppresses separate exports of the same remote device, as
diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 5a3c31a..a1e664b 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -12053,8 +12053,24 @@ crashes, data may be lost or the file system corrupted as a
result. The @command{sync} command ensures everything in memory
is written to disk.
-Any arguments are ignored, except for a lone @option{--help} or
-@option{--version} (@pxref{Common options}).
+If any argument is specified then only the specified files will be
+synchronized. It uses internally the syscall fsync(2) on each of them.
+
+If at least one file is specified, it is possible to change the
+synchronization policy with the following options. Also see
+@ref{Common options}.
+
+@table @samp
+@item --data
+@opindex --data
+Do not synchronize the file metadata unless it is required to maintain
+data integrity. It uses the syscall fdatasync(2).
+
+@item --file-system
+@opindex --file-system
+Synchronize all the I/O waiting for the file systems that contain the file.
+It uses the syscall syncfs(2).
+@end table
@exitstatus
diff --git a/m4/jm-macros.m4 b/m4/jm-macros.m4
index 58fdd97..79f124b 100644
--- a/m4/jm-macros.m4
+++ b/m4/jm-macros.m4
@@ -89,6 +89,7 @@ AC_DEFUN([coreutils_MACROS],
sethostname
siginterrupt
sync
+ syncfs
sysctl
sysinfo
tcgetpgrp
diff --git a/man/sync.x b/man/sync.x
index 7947bb7..6ced07e 100644
--- a/man/sync.x
+++ b/man/sync.x
@@ -3,4 +3,4 @@ sync \- flush file system buffers
[DESCRIPTION]
.\" Add any additional description here
[SEE ALSO]
-sync(2)
+fdatasync(2), fsync(2), sync(2), syncfs(2)
diff --git a/src/sync.c b/src/sync.c
index e9f4d7e..6c4d571 100644
--- a/src/sync.c
+++ b/src/sync.c
@@ -23,12 +23,31 @@
#include "system.h"
#include "error.h"
-#include "long-options.h"
+#include "quote.h"
/* The official name of this program (e.g., no 'g' prefix). */
#define PROGRAM_NAME "sync"
-#define AUTHORS proper_name ("Jim Meyering")
+#define AUTHORS \
+ proper_name ("Jim Meyering"), \
+ proper_name ("Giuseppe Scrivano")
+
+enum
+{
+ MODE_FILE,
+ MODE_DATA,
+ MODE_FILE_SYSTEM,
+ MODE_SYNC
+};
+
+static struct option const long_options[] =
+{
+ {"data", no_argument, NULL, MODE_DATA},
+ {"file-system", no_argument, NULL, MODE_FILE_SYSTEM},
+ {GETOPT_HELP_OPTION_DECL},
+ {GETOPT_VERSION_OPTION_DECL},
+ {NULL, 0, NULL, 0}
+};
void
usage (int status)
@@ -37,11 +56,21 @@ usage (int status)
emit_try_help ();
else
{
- printf (_("Usage: %s [OPTION]\n"), program_name);
+ printf (_("Usage: %s [OPTION] [PATH]...\n"), program_name);
fputs (_("\
Force changed blocks to disk, update the super block.\n\
\n\
+If one or more file paths are specified, sync only them,\n\
+use --data and --file-system to change the default behavior\n\
+\n\
"), stdout);
+
+ fputs (_("\
+ --file-system sync the file systems that contain the path\n\
+ --data flush the metadata only if needed later for\n\
+ data retrieval to be correctly handled\n\
+"), stdout);
+
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
emit_ancillary_info (PROGRAM_NAME);
@@ -49,9 +78,61 @@ Force changed blocks to disk, update the super block.\n\
exit (status);
}
+static bool
+sync_arg (int mode, char *file)
+{
+ int ret = -1;
+ int fd = open (file, O_RDONLY);
+ if (fd < 0)
+ {
+ error (0, errno, _("cannot open %s for reading"), quote (file));
+ return false;
+ }
+
+ switch (mode)
+ {
+ case MODE_FILE:
+ ret = fsync (fd);
+ break;
+
+ case MODE_DATA:
+ ret = fdatasync (fd);
+ break;
+
+#if HAVE_SYNCFS
+ case MODE_FILE_SYSTEM:
+ ret = syncfs (fd);
+ break;
+#endif
+
+ default:
+ error (EXIT_FAILURE, errno, _("invalid mode specified"));
+ break;
+ }
+
+ if (ret < 0)
+ {
+ error (0, errno, _("syncing error"));
+ return false;
+ }
+
+ if (close (fd) < 0)
+ {
+ error (0, errno, _("failed to close %s"), quote (file));
+ return false;
+ }
+
+ return true;
+}
+
int
main (int argc, char **argv)
{
+ bool args_specified;
+ int c, ret;
+ bool arg_data = false, arg_file_system = false;
+ int mode;
+
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
@@ -60,14 +141,68 @@ main (int argc, char **argv)
atexit (close_stdout);
- parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE, Version,
- usage, AUTHORS, (char const *) NULL);
- if (getopt_long (argc, argv, "", NULL, NULL) != -1)
- usage (EXIT_FAILURE);
+ while ((c = getopt_long (argc, argv, "", long_options, NULL))
+ != -1)
+ {
+ switch (c)
+ {
+ case MODE_DATA:
+ arg_data = true;
+ break;
+
+ case MODE_FILE_SYSTEM:
+ arg_file_system = true;
+ break;
+
+ case_GETOPT_HELP_CHAR;
+
+ case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
+
+ default:
+ usage (EXIT_FAILURE);
+ }
+ }
+
+ args_specified = optind < argc;
+
+ if (arg_data && arg_file_system)
+ {
+ error (EXIT_FAILURE, errno,
+ _("cannot specify both --data and --file-system"));
+ }
+
+ if (!args_specified && arg_data)
+ error (EXIT_FAILURE, errno, _("--data needs at least one argument"));
+
+ if (arg_data)
+ mode = MODE_DATA;
+ else if (! arg_file_system)
+ {
+ mode = args_specified ? MODE_FILE : MODE_SYNC;
+ }
+ else
+ {
+ /* On systems where syncfs is not available, or if no args are specified,
+ fallback to sync. */
+ if (HAVE_SYNCFS && args_specified)
+ mode = MODE_FILE_SYSTEM;
+ else
+ {
+ mode = MODE_SYNC;
+ }
+ }
- if (optind < argc)
- error (0, 0, _("ignoring all arguments"));
+ if (mode == MODE_SYNC)
+ {
+ sync ();
+ return EXIT_SUCCESS;
+ }
- sync ();
- return EXIT_SUCCESS;
+ ret = EXIT_SUCCESS;
+ for (; optind < argc; optind++)
+ {
+ if (! sync_arg (mode, argv[optind]))
+ ret = EXIT_FAILURE;
+ }
+ return ret;
}
--
2.1.0
GNU bug tracking system
Copyright (C) 1999 Darren O. Benham,
1997,2003 nCipher Corporation Ltd,
1994-97 Ian Jackson.