Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932762Ab2HPO5K (ORCPT ); Thu, 16 Aug 2012 10:57:10 -0400 Received: from mail-lpp01m010-f46.google.com ([209.85.215.46]:40013 "EHLO mail-lpp01m010-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753804Ab2HPO5G (ORCPT ); Thu, 16 Aug 2012 10:57:06 -0400 Date: Thu, 16 Aug 2012 18:57:00 +0400 From: Cyrill Gorcunov To: "J. Bruce Fields" Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Al Viro , Alexey Dobriyan , Andrew Morton , Pavel Emelyanov , James Bottomley , Matthew Helsley Subject: Re: [patch 4/8] fs, exportfs: Add export_encode_inode_fh helper Message-ID: <20120816145700.GB13382@moon> References: <20120815092116.700948346@openvz.org> <20120815092409.591460800@openvz.org> <20120815204546.GC25062@fieldses.org> <20120815210237.GF25421@moon> <20120815220622.GA28054@fieldses.org> <20120816062448.GA32081@moon> <20120816123814.GD1209@moon> <20120816124703.GE28054@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120816124703.GE28054@fieldses.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4401 Lines: 111 On Thu, Aug 16, 2012 at 08:47:03AM -0400, J. Bruce Fields wrote: > On Thu, Aug 16, 2012 at 04:38:14PM +0400, Cyrill Gorcunov wrote: > > On Thu, Aug 16, 2012 at 10:24:48AM +0400, Cyrill Gorcunov wrote: > > > > > > On the other hand, if you want a real filehandle then wouldn't you want > > > > > > to e.g. call the filesystem's ->encode_fh() if necessary, as > > > > > > exportfs_encode_fh() does? > > > > > > > > > > Well, one of the problem I hit when I've been trying to use encode_fh > > > > > is that every new implementation of encode_fh will require some size > > > > > (even unknown) in buffer where encoded data pushed. Correct me please > > > > > if I'm wrong. But with export_encode_inode_fh there is a small buffer > > > > > with pretty known size needed on stack needed for printing data in > > > > > fdinfo. > > > > > > > > You can just give encode_fh a too-small data and let it fail if it's not > > > > big enough. > > > > > > > > (In practice I think everyone supports NFSv3 filehandles which have a > > > > maximum size of 64 bytes.) > > > > > > I'll think about it, thanks! > > > > Hi Bruce, thinking a bit more I guess using general encode_fh is not that > > convenient since it operates with dentries while our fdinfo output deals > > with inodes. Thus I should either provide some new encode_fh variant > > which would deal with inodes directly without "parents". > > I can't see why that wouldn't work. Guys, would the patch below be more-less acceptible? In inotify I think we could pass "parent" as NULL and use general encode engine then (ie it will look like someone called for name_to_handle_at on inotify target). --- fs, exportfs: Add exportfs_encode_inode_fh helper This helpers allows to use per-sb encode_fh functionality where inodes come in as arguments (say the caller has no dentries to provide). Signed-off-by: Cyrill Gorcunov CC: Pavel Emelyanov CC: Al Viro CC: "J. Bruce Fields" CC: Alexey Dobriyan CC: Andrew Morton CC: James Bottomley --- fs/exportfs/expfs.c | 19 ++++++++++++++----- include/linux/exportfs.h | 2 ++ 2 files changed, 16 insertions(+), 5 deletions(-) Index: linux-2.6.git/fs/exportfs/expfs.c =================================================================== --- linux-2.6.git.orig/fs/exportfs/expfs.c +++ linux-2.6.git/fs/exportfs/expfs.c @@ -341,10 +341,21 @@ static int export_encode_fh(struct inode return type; } +int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid, + int *max_len, struct inode *parent) +{ + const struct export_operations *nop = inode->i_sb->s_export_op; + + if (nop) + return nop->encode_fh(inode, fid->raw, max_len, parent); + + return export_encode_fh(inode, fid, max_len, parent); +} +EXPORT_SYMBOL_GPL(exportfs_encode_inode_fh); + int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len, int connectable) { - const struct export_operations *nop = dentry->d_sb->s_export_op; int error; struct dentry *p = NULL; struct inode *inode = dentry->d_inode, *parent = NULL; @@ -357,10 +368,8 @@ int exportfs_encode_fh(struct dentry *de */ parent = p->d_inode; } - if (nop->encode_fh) - error = nop->encode_fh(inode, fid->raw, max_len, parent); - else - error = export_encode_fh(inode, fid, max_len, parent); + + error = exportfs_encode_inode_fh(inode, fid, max_len, parent); dput(p); return error; Index: linux-2.6.git/include/linux/exportfs.h =================================================================== --- linux-2.6.git.orig/include/linux/exportfs.h +++ linux-2.6.git/include/linux/exportfs.h @@ -177,6 +177,8 @@ struct export_operations { int (*commit_metadata)(struct inode *inode); }; +extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid, + int *max_len, struct inode *parent); extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len, int connectable); extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/