[LTP] [PATCH v2] utimensat01: Use common FS (ext4) with timestamps and attributes

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> >> If tmpdir is mounted on tmpfs then the test will fail with ENOTTY as
> >> this FS apparently does not support file attributes (inode
> >> flags). Instead we can test on ext4 where setting attributes and high
> >> precision timestamps is known to work.
> >> 
> >> We can not set all_filesystems because utimensat will fail to reset
> >> the timestamp to zero on at least exFAT and NTFS (FUSE and kernel
> >> versions). It is not clear yet what the expected behavior is or how
> >> the test could fail gracefully and requires investigation.
> >> 
> >> Also if we now get ENOTTY then it is assumed the file system does not
> >> support attributes and the test fails with TCONF. However the
> >> underlying FS could return some other errno (e.g. EINVAL on FUSE
> >> NTFS), but it is not clear what to expect, if anything and also
> >> requires further investigation.
> >> 
> >> Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
> >> ---
> >> 
> >> V2: Instead of trying to use all filesystems, just use one we know
> >>     works and is on most distros.
> >> 
> >> Obviously this is not ideal as this also expected to work on BTRFS,
> >> XFS etc. However the library doesn't allow us to specify this and
> >> modifying it would be quite intrusive. After the release this needs to
> >> be looked into.
> >> 
> >>  .../kernel/syscalls/utimensat/utimensat01.c   | 22 ++++++++++++++-----
> >>  1 file changed, 17 insertions(+), 5 deletions(-)
> >> 
> >> diff --git a/testcases/kernel/syscalls/utimensat/utimensat01.c b/testcases/kernel/syscalls/utimensat/utimensat01.c
> >> index fe490f441..42299eda8 100644
> >> --- a/testcases/kernel/syscalls/utimensat/utimensat01.c
> >> +++ b/testcases/kernel/syscalls/utimensat/utimensat01.c
> >> @@ -21,8 +21,9 @@
> >>  #include "time64_variants.h"
> >>  #include "tst_timer.h"
> >>  
> >> -#define TEST_FILE	"test_file"
> >> -#define TEST_DIR	"test_dir"
> >> +#define MNTPOINT 	"mntpoint"
> >> +#define TEST_FILE	MNTPOINT"/test_file"
> >> +#define TEST_DIR	MNTPOINT"/test_dir"
> >>  
> >>  static void *bad_addr;
> >>  
> >> @@ -182,7 +183,12 @@ static void change_attr(struct test_case *tc, int fd, int set)
> >>  	if (!tc->attr)
> >>  		return;
> >>  
> >> -	SAFE_IOCTL(fd, FS_IOC_GETFLAGS, &attr);
> >> +	if (ioctl(fd, FS_IOC_GETFLAGS, &attr)) {
> >> +		if (errno == ENOTTY)
> >> +			tst_brk(TCONF | TERRNO, "Attributes not supported by FS");
> >> +		else
> >> +			tst_brk(TBROK | TERRNO, "ioctl(fd, FS_IOC_GETFLAGS, &attr) failed");
> >> +	}
> >>  
> >>  	if (set)
> >>  		attr |= tc->attr;
> >> @@ -198,7 +204,11 @@ static void reset_time(char *pathname, int dfd, int flags, int i)
> >>  	struct stat sb;
> >>  
> >>  	memset(&ts, 0, sizeof(ts));
> >> -	tv->utimensat(dfd, pathname, &ts, flags);
> >> +	TEST(tv->utimensat(dfd, pathname, &ts, flags));
> >> +	if (TST_RET) {
> >> +		tst_res(TINFO | TTERRNO, "%2d: utimensat(%d, %s, {0, 0}, %d) failed",
> >> +			i, dfd, pathname, flags);
> >> +	}
> >>  
> >>  	TEST(stat(pathname, &sb));
> >>  	if (TST_RET) {
> >> @@ -305,5 +315,7 @@ static struct tst_test test = {
> >>  	.test_variants = ARRAY_SIZE(variants),
> >>  	.setup = setup,
> >>  	.needs_root = 1,
> >> -	.needs_tmpdir = 1,
> >> +	.mount_device = 1,
> >> +	.mntpoint = MNTPOINT,
> >> +	.dev_fs_type = "ext4",
> >
> > Do we have to specify ext4 here? Shouldn't that work with a default FS
> > for loop devices i.e. ext2?
> >
> > I do worry that this would disable the test on small embedded devices
> > without ext4 driver, not sure if there are still some around.
> >
> > But I think that defaulting to whatever have been choosen as a default
> > filesystem (may be passed in LTP_DEV_FS_TYPE env variable) would be
> > better band aid for now.
> 
> Oh, I didn't think ext2 supported these timestamps, but the test works
> so OK!

I guess that it really depends on the inode size the mkfs defaults to.
If we end up with 256 bytes there is extra space for sub-second timestamps.

I suppose that newer mkfs defaults to 256 bytes even for ext2 because
the 32bit values will overflow in 2038 anyways and changing these to
64bit gives two extra bits for the seconds value.

So my guess is that it may still produce TCONF on 10 year old
distributions, but the question here is if we really care.

-- 
Cyril Hrubis
chrubis@suse.cz