statfs64() does NOT return -1 and setting errno to EOVERFLOW when some
variables(like: f_bsize) overflowed in the returned struct.
reproducer:
step1. mount hugetlbfs with two different pagesize on ppc64 arch.
$ hugeadm --pool-pages-max 16M:0
$ hugeadm --create-mount
$ mount | grep -i hugetlbfs
none on /var/lib/hugetlbfs/pagesize-16MB type hugetlbfs
(rw,relatime,seclabel,pagesize=16777216)
none on /var/lib/hugetlbfs/pagesize-16GB type hugetlbfs
(rw,relatime,seclabel,pagesize=17179869184)
step2. compile & run this C program.
$ cat statfs64_test.c
#define _LARGEFILE64_SOURCE
#include <stdio.h>
#include <sys/statfs.h>
int main()
{
struct statfs64 sb;
int err;
err = statfs64("/var/lib/hugetlbfs/pagesize-16GB", &sb);
if (err)
return -1;
printf("sizeof f_bsize = %d, f_bsize=%ld\n", sizeof(sb.f_bsize),
sb.f_bsize);
return 0;
}
$ gcc -m32 statfs64_test.c
$ ./a.out
sizeof f_bsize = 4, f_bsize=0
Signed-off-by: Li Wang <liw...@redhat.com>
---
Notes:
This is my first patch to kernel fs part, I'm not sure if
this one useful, but just want someone have a look.
thanks~
fs/statfs.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/fs/statfs.c b/fs/statfs.c
index 083dc0a..849dde95 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -151,6 +151,23 @@ static int do_statfs64(struct kstatfs *st, struct statfs64
__user *p)
if (sizeof(buf) == sizeof(*st))
memcpy(&buf, st, sizeof(*st));
else {
+ if (sizeof buf.f_bsize == 4) {
+ if ((st->f_blocks | st->f_bfree | st->f_bavail |
+ st->f_bsize | st->f_frsize) &
+ 0xffffffff00000000ULL)
+ return -EOVERFLOW;
+ /*
+ * f_files and f_ffree may be -1; it's okay to stuff
+ * that into 32 bits
+ */
+ if (st->f_files != -1 &&
+ (st->f_files & 0xffffffff00000000ULL))
+ return -EOVERFLOW;
+ if (st->f_ffree != -1 &&
+ (st->f_ffree & 0xffffffff00000000ULL))
+ return -EOVERFLOW;
+ }
+
buf.f_type = st->f_type;
buf.f_bsize = st->f_bsize;
buf.f_blocks = st->f_blocks;
--
1.8.3.1
