On Wednesday, 01 December, 2010, Jeff Layton wrote: > A more common use case than CIFS or samba is going to be things like > backup programs. They commonly look at inode numbers in order to > identify hardlinks and may be horribly confused when there files that > have a link count >1 and inode number collisions with other files. > > That probably qualifies as an "enterprise-ready" show stopper...
I hope that a backup program, uses the pair (inode,fsid) to identify if two file are hardlinked... otherwise a backup of two filesystem mounted can be quite danguerous... >From the statfs(2) man page: [..] The f_fsid field [...] The general idea is that f_fsid contains some random stuff such that the pair (f_fsid,ino) uniquely determines a file. Some operating systems use (a variation on) the device number, or the device number combined with the file-system type. Several OSes restrict giving out the f_fsid field to the superuser only (and zero it for unprivileged users), because this field is used in the filehandle of the file system when NFS-exported, and giving it out is a security concern. And the btrfs_statfs function returns a different fsid for every subvolume. -- gpg key@ keyserver.linux.it: Goffredo Baroncelli (ghigo) <kreij...@inwind.it> Key fingerprint = 4769 7E51 5293 D36C 814E C054 BF04 F161 3DC5 0512 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
