[libvirt] [v2] storage: Ignore dangling symbol link for filesystem pool

[Osier Yang]

于 2010年12月21日 00:09, Eric Blake 写道:
> On 12/20/2010 12:14 AM, Osier Yang wrote:
>> If there is a dangling symbol link in filesystem pool, the pool
>
> s/symbol/symbolic/
>
>> will be failed to start or refresh, this patch is to fix it by
>
> s/will be failed/will fail/
>
>> ignoring it with a warning log.
>
>> @@ -986,6 +988,12 @@ virStorageBackendVolOpenCheckMode(const char *path, unsigned int flags)
>>       struct stat sb;
>>
>>       if ((fd = open(path, O_RDONLY|O_NONBLOCK|O_NOCTTY))<  0) {
>> +        if (areadlink(path)) {
>> +            VIR_WARN("cannot open volume '%s': %s", path,
>> +                     strerror(errno));
>> +            return -2;
>
> Memory leak - areadlink() returns a malloc()d string that the user must
> free.Also, areadlink() is expensive (in addition to malloc(), it makes
> several syscalls);

oh, just looked at the source code of areadlink, indeed, thanks.

a more efficient solution would be to check if errno
> is ELOOP or ENOENT (the only possibilities for a dangling symlink; any
> other error should return -1), and in those two cases a successful
> lstat() is sufficient to detect a broken symlink without resorting to
> reading its contents.
>

I guess you mean stat, lstat will not work here, as it doesn't follow
the *symbolic* link. what we need to do is to determine if the symbolic
link is dangling, so use "stat" to update the patch, v3 send, thanks
again.

Regards
Osier