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From: "Steve French" <smfrench@gmail.com>
To: samba-technical@lists.samba.org, linux-cifs-client@lists.samba.org
Cc: "Amit K. Arora" <aarora@linux.vnet.ibm.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: punching holes in files
Date: Thu, 1 Nov 2007 14:16:25 -0500	[thread overview]
Message-ID: <524f69650711011216s17cbc26ra337d70a0bde8d03@mail.gmail.com> (raw)

madvise_remove (in Linux) is used to free the backing store associated
with pages (punching a hole in a file).   This is one of the vfs
operations that we do not send over the wire to Samba (so this call
would return -ENOSYS locally).   Any thoughts on whether this could be
done with an obscure SetFileInfo level or FCNTL or whether it is worth
adding to the CIFS POSIX Extensions?

A second interesting question is whether to implement fallocate over
the wire.  sys_fallocate takes a range (and also a flag which
indicates whether to extend the size beyond end of file).
SET_FILE_ALLOCATION_INFO takes a size field rather than a range.  For
the case of the range starting at zero, we could simply call Trans2
set pathinfo (or file info) with SET_FILE_ALLOCATION_INFO.   Should we
add a CIFS POSIX Extension operation for this too?

By the way it looks like OCFS2 (not just ext4) implement these.

-- 
Thanks,

Steve

             reply	other threads:[~2007-11-01 19:16 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-01 19:16 Steve French [this message]
2007-11-01 23:17 ` punching holes in files Anton Altaparmakov
2007-11-02  7:30   ` Volker Lendecke
2007-11-03  0:43 ` Large SMBwriteX testing Jeremy Allison
2007-11-07 22:56   ` Steve French

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