From patchwork Sun Dec 18 08:43:02 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Aneesh Kumar K.V" X-Patchwork-Id: 132057 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id DC04BB6FEB for ; Sun, 18 Dec 2011 19:43:41 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751707Ab1LRInV (ORCPT ); Sun, 18 Dec 2011 03:43:21 -0500 Received: from e32.co.us.ibm.com ([32.97.110.150]:54070 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751522Ab1LRInU (ORCPT ); Sun, 18 Dec 2011 03:43:20 -0500 Received: from /spool/local by e32.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Sun, 18 Dec 2011 01:43:17 -0700 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id pBI8hHHS119286; Sun, 18 Dec 2011 01:43:17 -0700 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id pBI8hGGL031843; Sun, 18 Dec 2011 01:43:17 -0700 Received: from skywalker.linux.vnet.ibm.com ([9.124.88.48]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id pBI8h3cA031181; Sun, 18 Dec 2011 01:43:05 -0700 From: "Aneesh Kumar K.V" To: Al Viro , Sasha Levin Cc: ericvh@gmail.com, rminnich@sandia.gov, lucho@ionkov.net, davem@davemloft.net, jvrao@linux.vnet.ibm.com, v9fs-developer@lists.sourceforge.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] 9p: Don't use ATTR_* values from fs.h in userspace facing structs In-Reply-To: <87pqfmgtph.fsf@linux.vnet.ibm.com> References: <1324134422-16642-1-git-send-email-levinsasha928@gmail.com> <20111217174725.GW2203@ZenIV.linux.org.uk> <87pqfmgtph.fsf@linux.vnet.ibm.com> User-Agent: Notmuch/0.10.2+102~g61445d1 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) Date: Sun, 18 Dec 2011 14:13:02 +0530 Message-ID: <87mxaqgtih.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 x-cbid: 11121808-3270-0000-0000-000002A4BAB0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sun, 18 Dec 2011 14:08:50 +0530, "Aneesh Kumar K.V" wrote: > On Sat, 17 Dec 2011 17:47:25 +0000, Al Viro wrote: > > On Sat, Dec 17, 2011 at 05:07:02PM +0200, Sasha Levin wrote: > > > struct p9_iattr_dotl is userspace facing, but the 'valid' field is documented > > > as follows: > > > > > > * @valid: bitfield specifying which fields are valid > > > * same as in struct iattr > > > > > > Which means that the user has to know about kernel internal ATTR_* values. > > > > > > On Fri, 2011-12-16 at 23:30 +0000, Al Viro wrote: > > > > They *are* kernel internal values and 9P is asking for trouble exposing > > > > them. Translation: tomorrow we might reassign those as we bloody wish > > > > and any userland code that happens to rely on their values will break. > > > > At which point we'll handle complaints by pointing and laughing. > > > > > > > > It's a 9P bug; fix it there. Turning random internal constants into a part > > > > of ABI is not going to work. > > > > > > Signed-off-by: Sasha Levin > > > --- > > > fs/9p/vfs_inode_dotl.c | 31 ++++++++++++++++++++++++++++++- > > > include/net/9p/9p.h | 18 ++++++++++++++++++ > > > 2 files changed, 48 insertions(+), 1 deletions(-) > > > > > > diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c > > > index 0b5745e..a948214 100644 > > > --- a/fs/9p/vfs_inode_dotl.c > > > +++ b/fs/9p/vfs_inode_dotl.c > > > @@ -523,6 +523,35 @@ v9fs_vfs_getattr_dotl(struct vfsmount *mnt, struct dentry *dentry, > > > return 0; > > > } > > > > > > +int v9fs_vfs_iattr_to_9p_valid(u32 ia_valid) > > > +{ > > > + u32 valid = 0, i; > > > + static u32 attr_map[][2] = { > > > + {ATTR_MODE, P9_ATTR_MODE}, > > > + {ATTR_UID, P9_ATTR_UID}, > > > + {ATTR_SIZE, P9_ATTR_SIZE}, > > > + {ATTR_ATIME, P9_ATTR_ATIME}, > > > + {ATTR_MTIME, P9_ATTR_MTIME}, > > > + {ATTR_CTIME, P9_ATTR_CTIME}, > > > + {ATTR_ATIME_SET, P9_ATTR_ATIME_SET}, > > > + {ATTR_MTIME_SET, P9_ATTR_MTIME_SET}, > > > + {ATTR_FORCE, P9_ATTR_FORCE}, > > > + {ATTR_ATTR_FLAG, P9_ATTR_ATTR_FLAG}, > > > + {ATTR_KILL_SUID, P9_ATTR_KILL_SUID}, > > > + {ATTR_KILL_SGID, P9_ATTR_KILL_SGID}, > > > + {ATTR_FILE, P9_ATTR_FILE}, > > > + {ATTR_KILL_PRIV, P9_ATTR_KILL_PRIV}, > > > + {ATTR_OPEN, P9_ATTR_OPEN}, > > > + {ATTR_TIMES_SET, P9_ATTR_TIMES_SET}, > > > + }; > > > > a) ATTR_GID is lost > > b) passing ATTR_FILE is bloody pointless; look at what it does and > > realize that 9p doesn't as much as look at ia_file. > > c) ATTR_KILL_PRIV is very dubious; what's the legitimate use of that > > puppy in fs code? > > > > Look, that's the problem with exposing this stuff to protocol; you don't > > get clear semantics and are you seriously asking for trouble on kernel > > changes. Suppose tomorrow we get rid of e.g. ATTR_KILL_PRIV; what are you > > guys going to do? Hope that no 9p server has behaviour dependent on that > > flag being set or cleared? > > > > Don't turn the kernel internals into a part of ABI. And blind bulk remapping > > of constants is exactly that... > > > qemu part if you are interested. commit 9a45b894ab6d5e4480e721a40e8e8c160344c9fe Author: Aneesh Kumar K.V Date: Sat Dec 17 21:02:57 2011 +0530 hw/9pfs: iattr_valid flags are kernel internal flags map them to 9p values. Kernel internal values can change, add protocol values for these constant and use them. Signed-off-by: Aneesh Kumar K.V --- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c index b3fc3d0..567f6cb 100644 --- a/hw/9pfs/virtio-9p.c +++ b/hw/9pfs/virtio-9p.c @@ -1293,17 +1293,18 @@ out_nofid: complete_pdu(s, pdu, retval); } -/* From Linux kernel code */ -#define ATTR_MODE (1 << 0) -#define ATTR_UID (1 << 1) -#define ATTR_GID (1 << 2) -#define ATTR_SIZE (1 << 3) -#define ATTR_ATIME (1 << 4) -#define ATTR_MTIME (1 << 5) -#define ATTR_CTIME (1 << 6) -#define ATTR_MASK 127 -#define ATTR_ATIME_SET (1 << 7) -#define ATTR_MTIME_SET (1 << 8) +/* Attribute flags */ +#define P9_ATTR_MODE (1 << 0) +#define P9_ATTR_UID (1 << 1) +#define P9_ATTR_GID (1 << 2) +#define P9_ATTR_SIZE (1 << 3) +#define P9_ATTR_ATIME (1 << 4) +#define P9_ATTR_MTIME (1 << 5) +#define P9_ATTR_CTIME (1 << 6) +#define P9_ATTR_ATIME_SET (1 << 7) +#define P9_ATTR_MTIME_SET (1 << 8) + +#define P9_ATTR_MASK 127 static void v9fs_setattr(void *opaque) { @@ -1322,16 +1323,16 @@ static void v9fs_setattr(void *opaque) err = -EINVAL; goto out_nofid; } - if (v9iattr.valid & ATTR_MODE) { + if (v9iattr.valid & P9_ATTR_MODE) { err = v9fs_co_chmod(pdu, &fidp->path, v9iattr.mode); if (err < 0) { goto out; } } - if (v9iattr.valid & (ATTR_ATIME | ATTR_MTIME)) { + if (v9iattr.valid & (P9_ATTR_ATIME | P9_ATTR_MTIME)) { struct timespec times[2]; - if (v9iattr.valid & ATTR_ATIME) { - if (v9iattr.valid & ATTR_ATIME_SET) { + if (v9iattr.valid & P9_ATTR_ATIME) { + if (v9iattr.valid & P9_ATTR_ATIME_SET) { times[0].tv_sec = v9iattr.atime_sec; times[0].tv_nsec = v9iattr.atime_nsec; } else { @@ -1340,8 +1341,8 @@ static void v9fs_setattr(void *opaque) } else { times[0].tv_nsec = UTIME_OMIT; } - if (v9iattr.valid & ATTR_MTIME) { - if (v9iattr.valid & ATTR_MTIME_SET) { + if (v9iattr.valid & P9_ATTR_MTIME) { + if (v9iattr.valid & P9_ATTR_MTIME_SET) { times[1].tv_sec = v9iattr.mtime_sec; times[1].tv_nsec = v9iattr.mtime_nsec; } else { @@ -1359,13 +1360,13 @@ static void v9fs_setattr(void *opaque) * If the only valid entry in iattr is ctime we can call * chown(-1,-1) to update the ctime of the file */ - if ((v9iattr.valid & (ATTR_UID | ATTR_GID)) || - ((v9iattr.valid & ATTR_CTIME) - && !((v9iattr.valid & ATTR_MASK) & ~ATTR_CTIME))) { - if (!(v9iattr.valid & ATTR_UID)) { + if ((v9iattr.valid & (P9_ATTR_UID | P9_ATTR_GID)) || + ((v9iattr.valid & P9_ATTR_CTIME) + && !((v9iattr.valid & P9_ATTR_MASK) & ~P9_ATTR_CTIME))) { + if (!(v9iattr.valid & P9_ATTR_UID)) { v9iattr.uid = -1; } - if (!(v9iattr.valid & ATTR_GID)) { + if (!(v9iattr.valid & P9_ATTR_GID)) { v9iattr.gid = -1; } err = v9fs_co_chown(pdu, &fidp->path, v9iattr.uid, @@ -1374,7 +1375,7 @@ static void v9fs_setattr(void *opaque) goto out; } } - if (v9iattr.valid & (ATTR_SIZE)) { + if (v9iattr.valid & (P9_ATTR_SIZE)) { err = v9fs_co_truncate(pdu, &fidp->path, v9iattr.size); if (err < 0) { goto out;