[Qemu-devel] Re: [V9fs-developer] [PATCH] virtio-9p: getattr server implementation for 9P2000.L protocol.

["Aneesh Kumar K. V" <aneesh.kumar@linux.vnet.ibm.com>]

On Fri, 28 May 2010 16:08:43 +0530, Sripathi Kodi <sripathik@in.ibm.com> wrote:
> From: M. Mohan Kumar <mohan@in.ibm.com>
> 
> SYNOPSIS
> 
>       size[4] Tgetattr tag[2] fid[4]
> 
>       size[4] Rgetattr tag[2] lstat[n]
> 
>    DESCRIPTION
> 
>       The getattr transaction inquires about the file identified by fid.
>       The reply will contain a machine-independent directory entry,
>       laid out as follows:
> 
>          qid.type[1]
>             the type of the file (directory, etc.), represented as a bit
>             vector corresponding to the high 8 bits of the file's mode
>             word.
> 
>          qid.vers[4]
>             version number for given path
> 
>          qid.path[8]
>             the file server's unique identification for the file
> 
>          st_mode[4]
>             Permission and flags
> 
>          st_nlink[8]
>             Number of hard links
> 
>          st_uid[4]
>             User id of owner
> 
>          st_gid[4]
>             Group ID of owner
> 
>          st_rdev[8]
>             Device ID (if special file)
> 
>          st_size[8]
>             Size, in bytes
> 
>          st_blksize[8]
>             Block size for file system IO
> 
>          st_blocks[8]
>             Number of file system blocks allocated
> 
>          st_atime_sec[8]
>             Time of last access, seconds
> 
>          st_atime_nsec[8]
>             Time of last access, nanoseconds
> 
>          st_mtime_sec[8]
>             Time of last modification, seconds
> 
>          st_mtime_nsec[8]
>             Time of last modification, nanoseconds
> 
>          st_ctime_sec[8]
>             Time of last status change, seconds
> 
>          st_ctime_nsec[8]
>             Time of last status change, nanoseconds
> 
> 
> This patch implements the client side of getattr implementation for 9P2000.L.
> It introduces a new structure p9_stat_dotl for getting Linux stat information
> along with QID. The data layout is similar to stat structure in Linux user
> space with the following major differences:
> 
> inode (st_ino) is not part of data. Instead qid is.
> 
> device (st_dev) is not part of data because this doesn't make sense on the
> client.
> 
> All time variables are 64 bit wide on the wire. The kernel seems to use
> 32 bit variables for these variables. However, some of the architectures
> have used 64 bit variables and glibc exposes 64 bit variables to user
> space on some architectures. Hence to be on the safer side we have made
> these 64 bit in the protocol. Refer to the comments in
> include/asm-generic/stat.h
> 
> 

Can we just hold on this patch. There is a discussion to add
i_generation and inode create time to a variant of stat. So may be the
protocol bits need those

-aneesh