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.
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
>
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