Re: [PATCH] cifs/002: check nlink returned by fstat()

[Zorro Lang <zlang@kernel.org>]

On Fri, Jul 17, 2026 at 12:17:07PM -0500, Steve French wrote:
> On Fri, Jul 17, 2026 at 12:07 PM Zorro Lang <zlang@kernel.org> wrote:
> >
> > On Mon, Jul 13, 2026 at 03:16:58PM +0000, ChenXiaoSong wrote:
> > > From: ChenXiaoSong <chenxiaosong@kylinos.cn>
> > >
> > > Add a CIFS test to verify that fstat(2) returns the expected
> > > st_nlink value as hardlinks are created and removed.
> > >
> > > Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
> > > ---
> >
> > Wow, a new CIFS test case :)
> 
> This probably makes more sense as a generic test rather than cifs test
> since it doesn't have anything cifs specific.
> There are some additional cifs tests that could be added though.
> Bharath has a git tree with some of the cifs specific
> tests that could be added to the official repo:
> https://github.com/bharathsm-ms/xfstests-dev

Yeah, I have already suggested making this test case a generic one.

It's great to know that CIFS maintains its own specific test suite. If
needed, it's always welcome to submit Merge Request to fstests :)

Thanks,
Zorro

> 
> 
> 
> > >  src/Makefile       |   2 +-
> > >  src/fstat.c        | 200 +++++++++++++++++++++++++++++++++++++++++++++
> > >  tests/cifs/002     |  62 ++++++++++++++
> > >  tests/cifs/002.out |   2 +
> > >  4 files changed, 265 insertions(+), 1 deletion(-)
> > >  create mode 100644 src/fstat.c
> > >  create mode 100755 tests/cifs/002
> > >  create mode 100644 tests/cifs/002.out
> > >
> > > diff --git a/src/Makefile b/src/Makefile
> > > index 31ac43b2..b0886279 100644
> > > --- a/src/Makefile
> > > +++ b/src/Makefile
> > > @@ -6,7 +6,7 @@
> > >  TOPDIR = ..
> > >  include $(TOPDIR)/include/builddefs
> > >
> > > -TARGETS = dirstress fill fill2 getpagesize holes lstat64 \
> > > +TARGETS = dirstress fill fill2 getpagesize holes lstat64 fstat \
> > >       nametest permname randholes runas truncfile usemem \
> > >       mmapcat append_reader append_writer dirperf metaperf \
> > >       devzero feature alloc fault fstest t_access_root \
> > > diff --git a/src/fstat.c b/src/fstat.c
> > > new file mode 100644
> > > index 00000000..59221186
> > > --- /dev/null
> > > +++ b/src/fstat.c
> > > @@ -0,0 +1,200 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Copyright (C) 2026 KylinSoft Co., Ltd. All rights reserved.
> > > + * Author(s): ChenXiaoSong <chenxiaosong@kylinos.cn>
> > > + *
> > > + *  from
> > > + *  src/lstat64.c
> > > + *  Copyright (c) 2000-2002 Silicon Graphics, Inc.
> > > + *  All Rights Reserved.
> > > + */
> > > +
> > > +#include <fcntl.h>
> > > +#include <unistd.h>
> > > +#include <stdio.h>
> > > +#include <stdlib.h>
> > > +#include <string.h>
> > > +#include <time.h>
> > > +#include <sys/stat.h>
> > > +#include <sys/sysmacros.h>
> > > +
> > > +long timebuf;
> > > +
> > > +void
> > > +timesince(long timesec)
> > > +{
> > > +     long    d_since;        /* days */
> > > +     long    h_since;        /* hours */
> > > +     long    m_since;        /* minutes */
> > > +     long    s_since;        /* seconds */
> > > +
> > > +     s_since = timebuf - timesec;
> > > +     d_since = s_since / 86400l ;
> > > +     s_since -= d_since * 86400l ;
> > > +     h_since = s_since / 3600l ;
> > > +     s_since -= h_since * 3600l ;
> > > +     m_since = s_since / 60l ;
> > > +     s_since -= m_since * 60l ;
> > > +
> > > +     printf("(%05ld.%02ld:%02ld:%02ld)\n",
> > > +                     d_since, h_since, m_since, s_since);
> > > +}
> > > +
> > > +void
> > > +usage(void)
> > > +{
> > > +     fprintf(stderr, "Usage: fstat [-t] filename ...\n");
> > > +     exit(1);
> > > +}
> > > +
> > > +int
> > > +main(int argc, char **argv)
> > > +{
> > > +     struct stat     sbuf;
> > > +     int             i, c;
> > > +     int             terse_flag = 0;
> > > +
> > > +     while ((c = getopt(argc, argv, "t")) != EOF) {
> > > +             switch (c) {
> > > +                     case 't':
> > > +                             terse_flag = 1;
> > > +                             break;
> > > +
> > > +                     case '?':
> > > +                             usage();
> > > +             }
> > > +     }
> > > +     if (optind == argc) {
> > > +             usage();
> > > +     }
> > > +
> > > +     time(&timebuf);
> > > +
> > > +     for (i = optind; i < argc; i++) {
> > > +             char mode[] = "----------";
> > > +             int fd;
> > > +
> > > +             fd = open(argv[i], O_RDONLY | O_NONBLOCK);
> > > +             if (fd < 0) {
> > > +                     perror(argv[i]);
> > > +                     continue;
> > > +             }
> > > +
> > > +             if (fstat(fd, &sbuf) < 0) {
> > > +                     perror(argv[i]);
> > > +                     close(fd);
> > > +                     continue;
> > > +             }
> > > +
> > > +             if (terse_flag) {
> > > +                     printf("%s %llu ", argv[i], (unsigned long long)sbuf.st_size);
> > > +             }
> > > +             else {
> > > +                     printf("  File: \"%s\"\n", argv[i]);
> > > +                     printf("  Size: %-10llu", (unsigned long long)sbuf.st_size);
> > > +             }
> > > +
> > > +             if (sbuf.st_mode & S_IXOTH)
> > > +                     mode[9] = 'x';
> > > +             if (sbuf.st_mode & S_IWOTH)
> > > +                     mode[8] = 'w';
> > > +             if (sbuf.st_mode & S_IROTH)
> > > +                     mode[7] = 'r';
> > > +             if (sbuf.st_mode & S_IXGRP)
> > > +                     mode[6] = 'x';
> > > +             if (sbuf.st_mode & S_IWGRP)
> > > +                     mode[5] = 'w';
> > > +             if (sbuf.st_mode & S_IRGRP)
> > > +                     mode[4] = 'r';
> > > +             if (sbuf.st_mode & S_IXUSR)
> > > +                     mode[3] = 'x';
> > > +             if (sbuf.st_mode & S_IWUSR)
> > > +                     mode[2] = 'w';
> > > +             if (sbuf.st_mode & S_IRUSR)
> > > +                     mode[1] = 'r';
> > > +             if (sbuf.st_mode & S_ISVTX)
> > > +                     mode[9] = 't';
> > > +             if (sbuf.st_mode & S_ISGID)
> > > +                     mode[6] = 's';
> > > +             if (sbuf.st_mode & S_ISUID)
> > > +                     mode[3] = 's';
> > > +
> > > +             if (!terse_flag)
> > > +                     printf("   Filetype: ");
> > > +             switch (sbuf.st_mode & S_IFMT) {
> > > +             case S_IFSOCK:
> > > +                     if (!terse_flag)
> > > +                             puts("Socket");
> > > +                     mode[0] = 's';
> > > +                     break;
> > > +             case S_IFDIR:
> > > +                     if (!terse_flag)
> > > +                             puts("Directory");
> > > +                     mode[0] = 'd';
> > > +                     break;
> > > +             case S_IFCHR:
> > > +                     if (!terse_flag)
> > > +                             puts("Character Device");
> > > +                     mode[0] = 'c';
> > > +                     break;
> > > +             case S_IFBLK:
> > > +                     if (!terse_flag)
> > > +                             puts("Block Device");
> > > +                     mode[0] = 'b';
> > > +                     break;
> > > +             case S_IFREG:
> > > +                     if (!terse_flag)
> > > +                             puts("Regular File");
> > > +                     mode[0] = '-';
> > > +                     break;
> > > +             case S_IFLNK:
> > > +                     if (!terse_flag)
> > > +                             puts("Symbolic Link");
> > > +                     mode[0] = 'l';
> > > +                     break;
> > > +             case S_IFIFO:
> > > +                     if (!terse_flag)
> > > +                             puts("Fifo File");
> > > +                     mode[0] = 'f';
> > > +                     break;
> > > +             default:
> > > +                     if (!terse_flag)
> > > +                             puts("Unknown");
> > > +                     mode[0] = '?';
> > > +             }
> > > +
> > > +             if (terse_flag) {
> > > +                     printf("%s %d,%d\n", mode, (int)sbuf.st_uid, (int)sbuf.st_gid);
> > > +                     close(fd);
> > > +                     continue;
> > > +             }
> > > +
> > > +             printf("  Mode: (%04o/%s)", (unsigned int)(sbuf.st_mode & 07777), mode);
> > > +             printf("         Uid: (%d)", (int)sbuf.st_uid);
> > > +             printf("  Gid: (%d)\n", (int)sbuf.st_gid);
> > > +             printf("Device: %2d,%-2d", major(sbuf.st_dev),
> > > +                             minor(sbuf.st_dev));
> > > +             printf("  Inode: %-9llu", (unsigned long long)sbuf.st_ino);
> > > +             printf(" Links: %-5ld", (long)sbuf.st_nlink);
> > > +
> > > +             if ( ((sbuf.st_mode & S_IFMT) == S_IFCHR)
> > > +                 || ((sbuf.st_mode & S_IFMT) == S_IFBLK) )
> > > +                     printf("     Device type: %2d,%-2d\n",
> > > +                             major(sbuf.st_rdev), minor(sbuf.st_rdev));
> > > +             else
> > > +                     printf("\n");
> > > +
> > > +             printf("Access: %.24s",ctime(&sbuf.st_atime));
> > > +             timesince(sbuf.st_atime);
> > > +             printf("Modify: %.24s",ctime(&sbuf.st_mtime));
> > > +             timesince(sbuf.st_mtime);
> > > +             printf("Change: %.24s",ctime(&sbuf.st_ctime));
> > > +             timesince(sbuf.st_ctime);
> > > +
> > > +             if (i+1 < argc)
> > > +                     printf("\n");
> > > +
> > > +             close(fd);
> > > +     }
> > > +     exit(0);
> > > +}
> > > diff --git a/tests/cifs/002 b/tests/cifs/002
> > > new file mode 100755
> > > index 00000000..5f1eaffc
> > > --- /dev/null
> > > +++ b/tests/cifs/002
> > > @@ -0,0 +1,62 @@
> > > +#! /bin/bash
> > > +# SPDX-License-Identifier: GPL-2.0
> > > +# Copyright (C) 2026 KylinSoft Co., Ltd. All rights reserved.
> > > +# Author(s): ChenXiaoSong <chenxiaosong@kylinos.cn>
> > > +#
> > > +# FS QA Test No. cifs/002
> >
> > Although we are considering removing this specific line in the future, it is
> > currently still required to follow the standard format. Therefore, it should
> > be formatted as: FS QA Test 002
> >
> > > +#
> > > +# Check that fstat(2) returns the correct hard link count for a regular file.
> > > +# Regression test for kernel commit:
> > > +# 9dd1964ac59d ("smb/client: fix incorrect nlink returned by fstat()")
> > > +#
> > > +#  from
> > > +#  tests/generic/002
> >
> > The original test case is a generic test case, this one looks similar, doesn't
> > has any cifs specific test steps. So I think this can be a generic test case too
> >
> > > +#  Copyright (c) 2000-2001 Silicon Graphics, Inc.  All Rights Reserved.
> > > +#
> > > +. ./common/preamble
> > > +_begin_fstest metadata auto quick
> >
> > I think it also belong to "hardlink" group.
> >
> > > +
> > > +# Override the default cleanup function.
> > > +_cleanup()
> > > +{
> > > +     rm -f $tmp.*
> > > +     rm -rf $TEST_DIR/$$
> >
> >         cd /
> >         rm -r -f $tmp.*
> >         [ -d "$testdir" ] && rm -rf $testdir
> >
> > > +}
> > > +
> > > +status=0     # success is the default!
> > > +
> > > +_require_test
> > > +_require_hardlinks
> > > +_require_test_program fstat
> >
> > _fixed_by_fs_commit cifs 9dd1964ac59d \
> >         "smb/client: fix incorrect nlink returned by fstat()"
> >
> > > +
> > > +echo "Silence is goodness ..."
> >
> > If no specical reason, please keep the "Silence is golden".
> >
> > > +
> > > +testdir=$TEST_DIR/$$
> > > +mkdir -p $testdir
> > > +
> > > +touch $testdir/tmp.1
> > > +for l in 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
> > > +do
> >
> > for l in $(seq 2 20);do
> >
> > or
> >
> > for ((l=2; l<=20; l++))
> >
> > > +     ln $testdir/tmp.1 $testdir/tmp.$l
> > > +     x=`$here/src/fstat $testdir/tmp.1 | sed -n -e '/ Links: /s/.*Links: *//p'`
> >
> > I'm wondering if a specific src/fstat.c is needed. Can we replace the whole
> > src/fstat.c with `xfs_io -c stat ` ? Can you give it a try?
> >
> > > +     if [ "$l" -ne $x ]
> > > +     then
> >
> > if [ "$l" -ne $x ];then
> >
> > > +             echo "Arrgh, created link #$l and fstat looks like ..."
> > > +             $here/src/fstat $testdir/tmp.1
> > > +             status=1
> > > +     fi
> > > +done
> > > +
> > > +for l in 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
> > > +do
> >
> > for l in $(seq 20 -1 1);do
> >
> > or
> >
> > for ((l=20; l>=1; l--))
> >
> > > +     x=`$here/src/fstat $testdir/tmp.1 | sed -n -e '/ Links: /s/.*Links: *//p'`
> > > +     if [ "$l" -ne $x ]
> > > +     then
> > > +             echo "Arrgh, about to remove link #$l and fstat looks like ..."
> > > +             $here/src/fstat $testdir/tmp.1
> > > +             status=1
> > > +     fi
> > > +     rm -f $testdir/tmp.$l
> > > +done
> > > +
> > > +exit
> >
> > _exit 0
> >
> > Thanks,
> > Zorro
> >
> > > diff --git a/tests/cifs/002.out b/tests/cifs/002.out
> > > new file mode 100644
> > > index 00000000..11426b54
> > > --- /dev/null
> > > +++ b/tests/cifs/002.out
> > > @@ -0,0 +1,2 @@
> > > +QA output created by 002
> > > +Silence is goodness ...
> > > --
> > > 2.43.0
> > >
> > >
> 
> 
> 
> -- 
> Thanks,
> 
> Steve
>