On Fri, Jul 18, 2014 at 01:15:07AM -0500, Steve French wrote: > I created a patch to cifs.ko to add fallocate FALLOC_FL_KEEP_SIZE > support and did some tests against a Samba server (Samba 4.1.6 on ext4 > on Ubuntu) and also a Windows 8.1 server (NTFS file system) and ran > into an obvious problem. How to tell if the allocation size is > changed? Neither stat on the Samba server local file system nor the > Windows 8.1 properties show the size on disk changing. > > I am sending SMB3 SetInfo level 0x13 (set allocation size) and getting > success back from the Windows server and from Samba server. > > If I set the length past the end of file I get no error, but the > properties of the file in Windows Explorer still show the same (e.g. > zero) as the file size. If I try setting it to a size smaller than > the size of the file, the file shrinks (by the way this is an awkward > behavior to work around since on Linux fallocate can't shrink the file > - so if you have any ideas short of revalidating the file size before > deciding whether to send the fallocate request to Windows ...). > > Any ideas why Samba shows success but doesn't actually call ext4 to > update the allocation size? smbd does use VFS_FALLOCATE_KEEP_SIZE, which maps into fallocate FALLOC_FL_KEEP_SIZE if the underlying storage supports it. You need to set "strict allocate = true" on the share in order to get this behavior though. If you're setting allocation size smaller than file size we just use ftruncate, I don't see another possibility here. What behavior do you expect in the shrink case ? Jeremy. -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
