[LTP] [PATCH v1] libswap.c: Check free space with correct mnt path

[Petr Vorel]

Hi Wei, Li,

> Hi Wei,

> Good catch!

Great, thanks, merged!
(Tested at least on intel.)

> Reviewed-by: Li Wang <liwang@redhat.com>


> On Fri, Mar 1, 2024 at 9:51 AM Wei Gao via ltp <ltp@lists.linux.it> wrote:

> > The tst_fs_has_free should check fs size of mnt point.
> > But current code check ".", that means check /tmp/LTP_xxx
> > instead of /tmp/LTP_xxx/mntpoint.

> > Also tst_fs_has_free's "size" parameter's type is unsigned int,
> > it will overflow if encounter big filesystem block size(such as Btrfs
> > can use 64k).

I would personally added this as separate previous patch, but kept as is.

...
> > +++ b/libs/libltpswap/libswap.c
> > @@ -137,6 +137,7 @@ int make_swapfile(const char *swapfile, int blocks,
> > int safe)
> >         struct statvfs fs_info;
> >         unsigned long blk_size, bs;
> >         size_t pg_size = sysconf(_SC_PAGESIZE);
> > +       char mnt_path[100];

> >         if (statvfs(".", &fs_info) == -1)
> >                 return -1;
> > @@ -149,7 +150,8 @@ int make_swapfile(const char *swapfile, int blocks,
> > int safe)
> >         else
> >                 bs = blk_size;

> > -       if (!tst_fs_has_free(".", bs * blocks, TST_BYTES))
> > +       sscanf(swapfile, "%[^/]", mnt_path);

Although this should never fail, I changed it to check return value:

-       if (!tst_fs_has_free(".", bs * blocks, TST_BYTES))
+       if (sscanf(swapfile, "%[^/]", mnt_path) != 1)
+               tst_brk(TBROK, "sscanf failed");

And I'll ask Andrea Manzini to add SAFE_SSCANF() (easy hack).

Kind regards,
Petr