Re: [PATCH 1/5] nfsd: distinguish functions of NFSD_MAY_* flags

[Mi Jinlong <mijinlong@cn.fujitsu.com>]

J. Bruce Fields 写道:
> Most of the NFSD_MAY_* flags actually request permissions, but over the
> years we've accreted a few that modify the behavior of the permission or
> open code in other ways.
> 
> Distinguish the two cases a little more.  In particular, allow the
> shortcut at the start of nfsd_permission to ignore the
> non-permission-requesting bits.
> 
> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> ---
>  fs/nfsd/vfs.c |    2 +-
>  fs/nfsd/vfs.h |    3 +++
>  2 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index 2e1cebd..ac4f0b4 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -2027,7 +2027,7 @@ nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp,
>  	struct inode	*inode = dentry->d_inode;
>  	int		err;
>  
> -	if (acc == NFSD_MAY_NOP)
> +	if (acc & NFSD_MAY_MASK == NFSD_MAY_NOP)
>  		return 0;

  Maybe there is a problem, the priority of '==' is higher than '&', 
  this line equal to "if (acc & (NFSD_MAY_MASK == NFSD_MAY_NOP))",
  "return 0" will appears every time, I think it's not we really want.

  "if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP)" is we need,
  do you think so?

-- 
----
thanks
Mi Jinlong

>  #if 0
>  	dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n",
> diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
> index 9a370a5..1036913 100644
> --- a/fs/nfsd/vfs.h
> +++ b/fs/nfsd/vfs.h
> @@ -17,6 +17,9 @@
>  #define NFSD_MAY_SATTR		8
>  #define NFSD_MAY_TRUNC		16
>  #define NFSD_MAY_LOCK		32
> +#define NFSD_MAY_MASK		63
> +
> +/* extra hints to permission and open routines: */
>  #define NFSD_MAY_OWNER_OVERRIDE	64
>  #define NFSD_MAY_LOCAL_ACCESS	128 /* IRIX doing local access check on device special file*/
>  #define NFSD_MAY_BYPASS_GSS_ON_ROOT 256

-- 
----
thanks
Mi Jinlong