Re: [2/3] POHMELFS: Documentation.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Evgeniy Polyakov wrote:
Oplocks and leases are essentially lock on given file, which allows one
client to operate on it. POHMELFS does not have locks now, and they will
be created depending on how distributed server will require them. In the
simplesst case it can just lock file for writing and do not allow its
updates from other clients. Lock aciquite can be done at write_begin
time. Without lock and writeback cache in your case writeback for file Y
can happen before writeback for file X, but if client does not only
write, but also sync after its write, then yes, client will see later
updates after more earlier. POHMELFS does not broadcast its interest in
the file content until real writing happens, i.e. at writeback time.
Although I can add a mode, when the same will be done during
write_begin() time. In that case your example will work without sync.


For /locking/, life is easy, you don't have to worry about disallowing client updates, because locking is advisory. However, there are some guarantees you need for locking WRT write commit, and of course leases are a totally different animal where you do block client updates.

	Jeff


--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux