From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: [PATCH] fix ->setattr ATTR_SIZE locking for nfsd Date: Thu, 6 Jan 2005 18:33:28 +0100 Message-ID: <20050106173328.GA25506@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: roehrich@sgi.com, linux-fsdevel@vger.kernel.org Return-path: Received: from verein.lst.de ([213.95.11.210]:64237 "EHLO mail.lst.de") by vger.kernel.org with ESMTP id S262916AbVAFRdk (ORCPT ); Thu, 6 Jan 2005 12:33:40 -0500 To: akpm@osdl.org, mmontour@bycast.com Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Since the big direct I/O rework do_truncate takes i_alloc_sem before calling into ->setattr. Unfortunately the other callers of ->setattr with ATTR_SIZE, most notably nfsd don't take it. The (out of tree) XFS dmapi code relies wants to release i_alloc_sem and thus gets into problems like http://oss.sgi.com/bugzilla/show_bug.cgi?id=365 This patch moves acquiring and releasing i_alloc_sem into notify_change() to make the locking behaviour consistant. Index: fs/attr.c =================================================================== RCS file: /cvs/linux-2.6-xfs/fs/attr.c,v retrieving revision 1.2 diff -u -p -r1.2 attr.c --- fs/attr.c 16 Aug 2004 03:52:41 -0000 1.2 +++ fs/attr.c 6 Jan 2005 04:55:14 -0000 @@ -167,6 +167,9 @@ int notify_change(struct dentry * dentry if (!attr->ia_valid) return 0; + if (ia_valid & ATTR_SIZE) + down_write(&dentry->d_inode->i_alloc_sem); + if (inode->i_op && inode->i_op->setattr) { error = security_inode_setattr(dentry, attr); if (!error) @@ -183,6 +186,10 @@ int notify_change(struct dentry * dentry error = inode_setattr(inode, attr); } } + + if (ia_valid & ATTR_SIZE) + up_write(&dentry->d_inode->i_alloc_sem); + if (!error) { unsigned long dn_mask = setattr_mask(ia_valid); if (dn_mask) Index: fs/open.c =================================================================== RCS file: /cvs/linux-2.6-xfs/fs/open.c,v retrieving revision 1.7 diff -u -p -r1.7 open.c --- fs/open.c 16 Aug 2004 03:52:41 -0000 1.7 +++ fs/open.c 6 Jan 2005 04:55:15 -0000 @@ -202,10 +202,9 @@ int do_truncate(struct dentry *dentry, l newattrs.ia_size = length; newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; + down(&dentry->d_inode->i_sem); - down_write(&dentry->d_inode->i_alloc_sem); err = notify_change(dentry, &newattrs); - up_write(&dentry->d_inode->i_alloc_sem); up(&dentry->d_inode->i_sem); return err; }