2010/11/28 Jeff Layton <jlayton@xxxxxxxxxx>:
> On Sun, 28 Nov 2010 06:36:04 -0500
> Jeff Layton <jlayton@xxxxxxxxxx> wrote:
>
>> On Sun, 28 Nov 2010 11:12:49 +0300
>> Pavel Shilovsky <piastryyy@xxxxxxxxx> wrote:
>>
>> > On strict cache mode if we don't have Exclusive oplock we write a data to
>> > the server through cifs_user_write. Then if we Level II oplock store it in
>> > the cache, otherwise - invalidate inode pages affected by this writing.
>> >
>> > Signed-off-by: Pavel Shilovsky <piastryyy@xxxxxxxxx>
>> > ---
>> > fs/cifs/cifsfs.c | 40 ++++++++++++++++++++++++++++++++++++----
>> > 1 files changed, 36 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
>> > index bbb5294..901c82b 100644
>> > --- a/fs/cifs/cifsfs.c
>> > +++ b/fs/cifs/cifsfs.c
>> > @@ -598,12 +598,44 @@ static ssize_t cifs_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
>> > static ssize_t cifs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
>> > unsigned long nr_segs, loff_t pos)
>> > {
>> > - struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
>> > + struct inode *inode;
>> > + struct cifs_sb_info *cifs_sb;
>> > ssize_t written;
>> >
>> > - written = generic_file_aio_write(iocb, iov, nr_segs, pos);
>> > - if (!CIFS_I(inode)->clientCanCacheAll)
>> > - filemap_fdatawrite(inode->i_mapping);
>> > + inode = iocb->ki_filp->f_path.dentry->d_inode;
>> > +
>> > + if (CIFS_I(inode)->clientCanCacheAll)
>> > + return generic_file_aio_write(iocb, iov, nr_segs, pos);
>> > +
>> > + cifs_sb = CIFS_SB(iocb->ki_filp->f_path.dentry->d_sb);
>> > +
>> > + if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) == 0) {
>> > + int rc;
>> > +
>> > + written = generic_file_aio_write(iocb, iov, nr_segs, pos);
>> > +
>> > + rc = filemap_fdatawrite(inode->i_mapping);
>> > + if (rc)
>> > + cFYI(1, "cifs_file_aio_write: %d rc on %p inode",
>> > + rc, inode);
>> > + return written;
>> > + }
>> > +
>> > + /* in strict cache mode we need to write the data to the server exactly
>> > + from the pos to pos+len-1 rather than flush all affected pages
>> > + because it may cause a error with mandatory locks on these pages but
>> > + not on the region from pos to ppos+len-1 */
>>
>> Again, please fix the comment style. Here: ^^^^
>>
>> > + written = cifs_user_write(iocb->ki_filp, iov->iov_base,
>> > + iov->iov_len, &pos);
>> > +
>> > + iocb->ki_pos = pos;
>> > +
>> > + /* if we were successful - invalidate inode pages the write affected */
>> > + if (written > 0)
>> > + invalidate_mapping_pages(inode->i_mapping,
>> > + (pos-written) >> PAGE_CACHE_SHIFT,
>> > + (pos-1) >> PAGE_CACHE_SHIFT);
>> > +
>> > return written;
>> > }
>> >
>>
>> May god have mercy on anyone who tries to mix strictcache and mmap.
>>
>> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
>
> (cc'ing Suresh so he can comment)
>
> Actually...I'm going to withdraw my Reviewed-by tag here for now. This
> bare invalidate_mapping_pages doesn't deal with fscache.
>
> I think I need to understand what's intended when someone specifies
> strictcache and fsc before I can ack this. The simple answer would be
> that they are mutually exclusive, but if that's the case then the patch
> that adds the mount option needs to deal with that appropriately.
I don't think they can live together. I think we should do smth like a
following in mount options parsing:
...
if (opt == fscache) {
vol->fscahe = 1;
vol->strictcache = 0;
}
...
if (opt == strictcache) {
vol->strictcache = 1;
vol->fscache = 0;
}
So, if user specify both only the last will affect the client
behavior. Also we should add this information into cifs manpage.
Thoughts?
--
Best regards,
Pavel Shilovsky.
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