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SubjectRe: [PATCH v2] f2fs: fix up f2fs_get_parent issue to retrieve correct parent inode number
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2012-12-14 (금), 14:41 +0900, Namjae Jeon:
> 2012/12/14, Jaegeuk Kim <jaegeuk.kim@samsung.com>:
> > Hi,
> >
> >> diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c
> >> index a60f042..5e48bac 100644
> >> --- a/fs/f2fs/hash.c
> >> +++ b/fs/f2fs/hash.c
> >> @@ -76,6 +76,10 @@ f2fs_hash_t f2fs_dentry_hash(const char *name, int
> >> len)
> >> const char *p;
> >> __u32 in[8], buf[4];
> >>
> >> + if ((len <= 2) && (name[0] == '.') &&
> >> + (name[1] == '.' || name[1] == '\0'))
> >> + return 0;
> >
> > If len == 1, we should avoid referencing name[1].
> > Likewise VFS does, I rewrote that like below.
> >
> > if (name[0] == '.') {
> > switch (len) {
> > case 1:
> > return 0;
> > case 2:
> > if (name[1] == '.')
> > return 0;
> > }
> > }
> >
> > So, how about this patch?
>
> I think that there is no issue on current patch. Since, the strings
> are always expected to be NULL terminated.
>
> "." should include '\0', So we can distingsh by checking only name[0], name[1].
>
> When we do:
> char *ptr="hello"; -> it will always be NULL terminated -> "hello" in
> memory followed by '\0';
> when we reserver space
> char ptr[5];-> We need to reserver space for '\0' at the end.

Got it.
I found that NULL is added to the dentry->d_name as follows.

In __d_alloc(),
dentry->d_name.len = name->len;
dentry->d_name.hash = name->hash;
memcpy(dname, name->name, name->len);
dname[name->len] = 0;

I'll merge your patch. :)
Thanks,

--
Jaegeuk Kim
Samsung
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