[Box Backup] backup on nfs-mounted storage
Martin Ebourne
boxbackup@fluffy.co.uk
Thu, 19 Oct 2006 11:38:19 +0100
Ben Summers <ben@fluffy.co.uk> wrote:
> What happens if you use both? Are the two mechanism independent?
From the manpage on Linux:
flock(2) does not lock files over NFS. Use fcntl(2) instead: that does
work over NFS, given a sufficiently recent version of Linux and a
server which supports locking.
Since kernel 2.0, flock(2) is implemented as a system call in its own
right rather than being emulated in the GNU C library as a call to
fcntl(2). This yields true BSD semantics: there is no interaction
between the types of lock placed by flock(2) and fcntl(2), and flock(2)
does not detect deadlock.
Hence the wariness over new holes...
What does BSD do about file locking over NFS?
Cheers,
Martin.