io: Return UNSUPPORTED if filesystem do not support 64 bit timestamps

Some Linux filesystems might not fully support 64 bit timestamps [1],
which make some Linux specific tests to fail when they check for the
functionality.

This patch adds a new libsupport function, support_path_support_time64,
that returns whether the target file supports or not 64 bit timestamps.
The support is checked by issuing a utimensat and verifying both the
last access and last modification time against a statx call.

The tests that might fail are also adjusted to check the file support
as well:

  $ dd if=/dev/zero of=loopbackfile.img bs=100M count=1
  1+0 records in
  1+0 records out
  104857600 bytes (105 MB, 100 MiB) copied, 0,0589568 s, 1,8 GB/s
  $ sudo losetup -fP loopbackfile.img
  $ mkfs.xfs loopbackfile.img
  meta-data=loopbackfile.img       isize=512    agcount=4, agsize=6400 blks
           =                       sectsz=512   attr=2, projid32bit=1
           =                       crc=1        finobt=1, sparse=1, rmapbt=0
           =                       reflink=1
  data     =                       bsize=4096   blocks=25600, imaxpct=25
           =                       sunit=0      swidth=0 blks
  naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
  log      =internal log           bsize=4096   blocks=1368, version=2
           =                       sectsz=512   sunit=0 blks, lazy-count=1
  realtime =none                   extsz=4096   blocks=0, rtextents=0
  $ mkdir loopfs
  $ sudo mount -o loop /dev/loop0 loopfs/
  $ sudo chown -R azanella:azanella loopfs
  $ TMPDIR=loopfs/ ./testrun.sh misc/tst-utimes
  error: ../sysdeps/unix/sysv/linux/tst-utimes.c:55: File loopfs//utimesfECsK1 does not support 64-bit timestamps

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1795576

3 files changed, 19 insertions, 3 deletions

diff --git a/sysdeps/unix/sysv/linux/tst-futimens.c b/sysdeps/unix/sysv/linux/tst-futimens.c
index 8f48cfee63..785cd87557 100644
--- a/sysdeps/unix/sysv/linux/tst-futimens.c
+++ b/sysdeps/unix/sysv/linux/tst-futimens.c
@@ -21,10 +21,12 @@
 #include <stdlib.h>
 #include <sys/stat.h>
 #include <support/check.h>
+#include <support/support.h>
 #include <support/xunistd.h>
 #include <support/temp_file.h>
 
 static int temp_fd = -1;
+static char *testfile;
 
 /* struct timespec array with Y2038 threshold minus 2 and 1 seconds.  */
 const struct timespec t1[2] = { { 0x7FFFFFFE, 0 },  { 0x7FFFFFFF, 0 } };
@@ -39,13 +41,17 @@ const struct timespec t3[2] = { { 0x7FFFFFFE, 0 },  { 0x80000002ULL, 0 } };
 static void
 do_prepare (int argc, char *argv[])
 {
-  temp_fd = create_temp_file ("futimensat", NULL);
+  temp_fd = create_temp_file ("futimensat", &testfile);
   TEST_VERIFY_EXIT (temp_fd > 0);
 }
 
 static int
 test_futimens_helper (const struct timespec *ts)
 {
+  if (!support_path_support_time64 (testfile))
+    FAIL_UNSUPPORTED ("File %s does not support 64-bit timestamps",
+		      testfile);
+
   struct stat64 st;
   int result;
   time_t t;
diff --git a/sysdeps/unix/sysv/linux/tst-utime.c b/sysdeps/unix/sysv/linux/tst-utime.c
index 6735421657..21e4e41dea 100644
--- a/sysdeps/unix/sysv/linux/tst-utime.c
+++ b/sysdeps/unix/sysv/linux/tst-utime.c
@@ -23,11 +23,12 @@
 #include <sys/types.h>
 #include <utime.h>
 #include <support/check.h>
+#include <support/support.h>
 #include <support/xunistd.h>
 #include <support/temp_file.h>
 
 static int temp_fd = -1;
-char *testfile;
+static char *testfile;
 
 /* struct utimbuf with Y2038 threshold minus 2 and 1 seconds.  */
 const static struct utimbuf t1 = { 0x7FFFFFFE, 0x7FFFFFFF };
@@ -49,6 +50,10 @@ do_prepare (int argc, char *argv[])
 static int
 test_utime_helper (const struct utimbuf *ut)
 {
+  if (!support_path_support_time64 (testfile))
+    FAIL_UNSUPPORTED ("File %s does not support 64-bit timestamps",
+		      testfile);
+
   struct stat64 st;
   int result;
   time_t t;
diff --git a/sysdeps/unix/sysv/linux/tst-utimes.c b/sysdeps/unix/sysv/linux/tst-utimes.c
index 8c7b006a22..0f23e44897 100644
--- a/sysdeps/unix/sysv/linux/tst-utimes.c
+++ b/sysdeps/unix/sysv/linux/tst-utimes.c
@@ -22,11 +22,12 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <support/check.h>
+#include <support/support.h>
 #include <support/xunistd.h>
 #include <support/temp_file.h>
 
 static int temp_fd = -1;
-char *testfile;
+static char *testfile;
 
 /* struct timeval array with Y2038 threshold minus 2 and 1 seconds.  */
 const static struct timeval t1[2] = { { 0x7FFFFFFE, 0 },  { 0x7FFFFFFF, 0 } };
@@ -50,6 +51,10 @@ do_prepare (int argc, char *argv[])
 static int
 test_utime_helper (const struct timeval *tv)
 {
+  if (!support_path_support_time64 (testfile))
+    FAIL_UNSUPPORTED ("File %s does not support 64-bit timestamps",
+		      testfile);
+
   struct stat64 st;
   int result;
   time_t t;