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

On 12/20/2010 11:47 PM, Osier Yang wrote: > > 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. No, I really meant lstat(). If stat() would have failed because of a dangling symlink, then open() will fail for the same reasons. Therefore, check errno before lstat, and use the successful lstat as proof that a symlink is in place but that stat()ing the symlink would fail because it is dangling. if (open(f)< 0) { if ((errno == ENOENT || errno == ELOOP)&& lstat(f, buf) == 0) { /* Dangling symlink, since lstat() passed but open failed. */ log message about ignored file return -2; } either an unrelated errno, like EACCES, or we got ENOENT because the file was deleted after readdir but before open/lstat error message about unaccessible file return -1; }