I don't know what local file system that does not support preallocate. But I test nfs. It return "Operation not supported" and create a zero size file. # xfs_io -f -c "resvsp 4 4" nfs/file XFS_IOC_RESVSP64: Operation not supported # echo $? 0 # du -h nfs/file 0 nfs/file ----- Original Message ----- > From: "Steve French" <smfrench@xxxxxxxxx> > To: "Xiaoli Feng" <xifeng@xxxxxxxxxx> > Cc: "CIFS" <linux-cifs@xxxxxxxxxxxxxxx>, "Dave Chinner" <dchinner@xxxxxxxxxx> > Sent: Saturday, March 23, 2019 12:01:50 AM > Subject: Re: CIFS support preallocate partially > > No preallocate is actually sent on the wire (other than creating the > file) in the example you tried. Some servers do not support > preallocate - do you know the expected behavior on a local file system > that does not support preallocate whether it should 1) fail to create > the file and return an error or 2) succeed in creating the file (even > though couldn't preallocate the size). > > Looking at the code I am surprised it is not returning an error > message though it looks like smb3_simple_falloc would return an > EOPNOTSUPP error (at least if allocating more than a few pages beyond > end of file) > > On Fri, Mar 22, 2019 at 7:26 AM Xiaoli Feng <xifeng@xxxxxxxxxx> wrote: > > > > Hello, > > > > Use xfs_io to test preallocate. It returns successfuly. But it's a empty > > file. And doesn't allocate space. > > > > # mount //localhost/cifs ~/cifs > > # xfs_io -f -c "resvsp 4 4" cifs/file > > # du -h cifs/file > > 0 cifs/file > > > > > > Test on xfs: > > # rm -rf file > > # xfs_io -f -c "resvsp 4 4" file > > # du -h file > > 4.0K file > > > > Is it expected for cifs? I think the size should be a block size(1M for > > cifs). > > > > Thanks. > > > > -- > > Best regards! > > XiaoLi Feng 冯小丽 > > > > Red Hat Software (Beijing) Co.,Ltd > > filesystem-qe Team > > IRC:xifeng，#channel: fs-qe > > Tel:+86-10-8388112 > > 9/F, Raycom > > > > -- > Thanks, > > Steve >
