FYI: questionable xfsdump code

Marc Lehmann
2015-07-28T06:33:44Z

Hi!

While causally browsing xfsdump code,I found this, in
common/getdents.c:getdents_wrap (in xfsdump

off64_t last_offset = -1;

...

while ((char *)kdp < kbuf + retval) {
...

if ((sizeof(dp->d_ino) != sizeof(kdp->d_ino))
|| (sizeof(dp->d_off) != sizeof(kdp->d_off))) {
/* Overflow. If there was at least one entry
before this one, return them without error,
otherwise signal overflow. */
if (last_offset != -1) {
lseek64(fd, last_offset, SEEK_SET);
return (char *)dp - buf;
}
errno = EOVERFLOW;
return -1;
}

last_offset = d_off;

...
}

While not necessarily a bug, this comment is very confused - there is no
way to reach the code inside the if with last_offset != -1, as the if
condition is a compiletime constant.

This might be harmless dead code from some refactorisation gone wrong,
or indicative of some bug due to some logic error. In any case, I just
wanted to bring it to your attention.

And as a side note, memcpy would be more efficient here, especially as it
is called very often, (and especially so on irix :-):

memmove(dp->d_name, kdp->d_name,
old_reclen - offsetof(struct kernel_dirent64, d_name));

--
The choice of a Deliantra, the free code+content MORPG
-----==- _GNU_ http://www.deliantra.net
----==-- _ generation
---==---(_)__ __ ____ __ Marc Lehmann
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