On Tue, May 07, 2019 at 02:29:43PM -0400, Vivek Goyal wrote:
> On Tue, May 07, 2019 at 01:58:10PM +0800, Liu Bo wrote:
> > This is to let virtiofs daemon to do inline fallocate to preallocate
> > space for this mapping.
> >
> > Signed-off-by: Liu Bo <[email protected]>
> > ---
> > fs/fuse/file.c | 21 ++++++++++++++-------
> > 1 file changed, 14 insertions(+), 7 deletions(-)
> >
> > diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> > index 488e932f..6f403c8 100644
> > --- a/fs/fuse/file.c
> > +++ b/fs/fuse/file.c
> > @@ -251,8 +251,8 @@ static void free_dax_mapping(struct fuse_conn *fc,
> >
> > /* offset passed in should be aligned to FUSE_DAX_MEM_RANGE_SZ */
> > static int fuse_setup_one_mapping(struct inode *inode,
> > - struct file *file, loff_t offset,
> > - struct fuse_dax_mapping *dmap)
> > + struct file *file, loff_t offset, unsigned
> > flags,
> > + struct fuse_dax_mapping *dmap)
> > {
> > struct fuse_conn *fc = get_fuse_conn(inode);
> > struct fuse_inode *fi = get_fuse_inode(inode);
> > @@ -276,14 +276,21 @@ static int fuse_setup_one_mapping(struct inode *inode,
> > inarg.fh = -1;
> > inarg.moffset = dmap->window_offset;
> > inarg.len = FUSE_DAX_MEM_RANGE_SZ;
> > +
> > + /*
> > + * with IOMAP_WRITE, virtiofs daemon will make sure space is
> > + * allocated for the range.
> > + */
> > if (file) {
> > - inarg.flags |= (file->f_mode & FMODE_WRITE) ?
> > - FUSE_SETUPMAPPING_FLAG_WRITE : 0;
> > + if (file->f_mode & FMODE_WRITE &&
> > + flags & IOMAP_WRITE)
> > + inarg.flags |= FUSE_SETUPMAPPING_FLAG_WRITE;
> > inarg.flags |= (file->f_mode & FMODE_READ) ?
> > FUSE_SETUPMAPPING_FLAG_READ : 0;
> > } else {
> > inarg.flags |= FUSE_SETUPMAPPING_FLAG_READ;
> > - inarg.flags |= FUSE_SETUPMAPPING_FLAG_WRITE;
> > + if (flags & IOMAP_WRITE)
> > + inarg.flags |= FUSE_SETUPMAPPING_FLAG_WRITE;
>
> Not sure we can afford to map a mapping read only. We don't have a
> mechanism yet to upgrade a mapping. IOW, what if one process opens
> file read only and does some read. This will lead to a mapping setup
> with FUSE_SETUPMAPPING_FLAG_READ which will be cached. Now another process
> might open file read/write and try to write to same mapping without
> having to go through setupmapping path again and will run into this
> -ENOSPC again.
You're right, patch 2 provides a "mkwrite" helper to map the mapping RW.
thanks,
-liubo
>
> Vivek
>
> > }
> > args.in.h.opcode = FUSE_SETUPMAPPING;
> > args.in.h.nodeid = fi->nodeid;
> > @@ -1847,8 +1854,8 @@ static int fuse_iomap_begin(struct inode *inode,
> > loff_t pos, loff_t length,
> >
> > /* Setup one mapping */
> > ret = fuse_setup_one_mapping(inode, NULL,
> > - ALIGN_DOWN(pos, FUSE_DAX_MEM_RANGE_SZ),
> > - alloc_dmap);
> > + ALIGN_DOWN(pos, FUSE_DAX_MEM_RANGE_SZ),
> > + flags, alloc_dmap);
> > if (ret < 0) {
> > printk("fuse_setup_one_mapping() failed. err=%d"
> > " pos=0x%llx\n", ret, pos);
> > --
> > 1.8.3.1
> >
> > _______________________________________________
> > Virtio-fs mailing list
> > [email protected]
> > https://www.redhat.com/mailman/listinfo/virtio-fs
