[PATCH] xfs_io: add AT_UTIME_BTIME support

Omar Sandoval
2019-02-14T10:01:12Z

From: Omar Sandoval <osandov@fb.com>

In order to test updating btime, make the utimes command optionally take
the btime timestamp.

Signed-off-by: Omar Sandoval <osandov@fb.com>
---
io/utimes.c | 41 +++++++++++++++++++++++++++++++----------
man/man8/xfs_io.8 | 5 +++--
2 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/io/utimes.c b/io/utimes.c
index 40117472..72ce68f3 100644
--- a/io/utimes.c
+++ b/io/utimes.c
@@ -4,11 +4,18 @@
* All Rights Reserved.
*/

+#include <fcntl.h>
+#include <sys/syscall.h>
+
#include "command.h"
#include "input.h"
#include "init.h"
#include "io.h"

+#ifndef AT_UTIME_BTIME
+#define AT_UTIME_BTIME 0x8000
+#endif
+
static cmdinfo_t utimes_cmd;

static void
@@ -16,9 +23,10 @@ utimes_help(void)
{
printf(_(
"\n"
-" Update file atime and mtime of the current file with nansecond precision.\n"
+" Update file atime, mtime, and optionally btime of the current file with\n"
+" nansecond precision.\n"
"\n"
-" Usage: utimes atime_sec atime_nsec mtime_sec mtime_nsec.\n"
+" Usage: utimes atime_sec atime_nsec mtime_sec mtime_nsec [btime_sec btime_nsec]\n"
" *_sec: Seconds elapsed since 1970-01-01 00:00:00 UTC.\n"
" *_nsec: Nanoseconds since the corresponding *_sec.\n"
"\n"));
@@ -29,9 +37,13 @@ utimes_f(
int argc,
char **argv)
{
- struct timespec t[2];
+ struct timespec t[3];
+ int flags = 0;
int result;

+ if (argc == 6)
+ return command_usage(&utimes_cmd);
+
/* Get the timestamps */
result = timespec_from_string(argv[1], argv[2], &t[0]);
if (result) {
@@ -43,13 +55,22 @@ utimes_f(
fprintf(stderr, "Bad value for mtime\n");
return 0;
}
-
- /* Call futimens to update time. */
- if (futimens(file->fd, t)) {
- perror("futimens");
- return 0;
+ if (argc == 7) {
+ result = timespec_from_string(argv[5], argv[6], &t[2]);
+ if (result) {
+ fprintf(stderr, "Bad value for btime\n");
+ return 0;
+ }
+ flags |= AT_UTIME_BTIME;
}

+ /*
+ * Use syscall() because the glibc wrapper for utimensat() disallows a
+ * NULL pathname.
+ */
+ if (syscall(SYS_utimensat, file->fd, NULL, t, flags))
+ perror("utimensat");
+
return 0;
}

@@ -59,9 +80,9 @@ utimes_init(void)
utimes_cmd.name = "utimes";
utimes_cmd.cfunc = utimes_f;
utimes_cmd.argmin = 4;
- utimes_cmd.argmax = 4;
+ utimes_cmd.argmax = 6;
utimes_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
- utimes_cmd.args = _("atime_sec atime_nsec mtime_sec mtime_nsec");
+ utimes_cmd.args = _("atime_sec atime_nsec mtime_sec mtime_nsec [btime_sec btime_nsec]");
utimes_cmd.oneline = _("Update file times of the current file");
utimes_cmd.help = utimes_help;

diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
index fbf50df5..dbf8098b 100644
--- a/man/man8/xfs_io.8
+++ b/man/man8/xfs_io.8
@@ -827,8 +827,9 @@ verbose output will be printed.
.RE
.PD
.TP
-.BI utimes " atime_sec atime_nsec mtime_sec mtime_nsec"
-The utimes command changes the atime and mtime of the current file.
+.BI utimes " atime_sec atime_nsec mtime_sec mtime_nsec [btime_sec btime_nsec]"
+The utimes command changes the atime, mtime, and optionally btime of the
+current file.
sec uses UNIX timestamp notation and is the seconds elapsed since
1970-01-01 00:00:00 UTC.
nsec is the nanoseconds since the sec. This value needs to be in
--
2.20.1