Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754523AbXHIPak (ORCPT ); Thu, 9 Aug 2007 11:30:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S937890AbXHIP3q (ORCPT ); Thu, 9 Aug 2007 11:29:46 -0400 Received: from mail-gw1.sa.eol.hu ([212.108.200.67]:40606 "EHLO mail-gw1.sa.eol.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756917AbXHIP3n (ORCPT ); Thu, 9 Aug 2007 11:29:43 -0400 Message-Id: <20070809152905.362102628@szeredi.hu> References: <20070809152744.519270818@szeredi.hu> User-Agent: quilt/0.45-1 Date: Thu, 09 Aug 2007 17:27:47 +0200 From: miklos@szeredi.hu To: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Al Viro , Christoph Hellwig Subject: [RFC PATCH 3/4] allow filesystems to implement atomic open+truncate Content-Disposition: inline; filename=vfs_atomic_open_truncate.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2895 Lines: 83 From: Miklos Szeredi Add a new attribute flag ATTR_OPEN, with the meaning: "truncation was initiated by open() due to the O_TRUNC flag". This way filesystems wanting to implement truncation within their ->open() method can ignore such truncate requests. This is a quick & dirty hack, but it comes for free. When (if) we implement a proper low-level open+create+truncate inode operation, this can go away. Signed-off-by: Miklos Szeredi --- Index: linux/fs/namei.c =================================================================== --- linux.orig/fs/namei.c 2007-08-09 16:47:30.000000000 +0200 +++ linux/fs/namei.c 2007-08-09 16:49:07.000000000 +0200 @@ -1655,8 +1655,10 @@ int may_open(struct nameidata *nd, int a error = locks_verify_locked(inode); if (!error) { DQUOT_INIT(inode); - - error = do_truncate(dentry, 0, ATTR_MTIME|ATTR_CTIME, NULL); + + error = do_truncate(dentry, 0, + ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, + NULL); } put_write_access(inode); if (error) Index: linux/include/linux/fs.h =================================================================== --- linux.orig/include/linux/fs.h 2007-08-09 16:48:45.000000000 +0200 +++ linux/include/linux/fs.h 2007-08-09 16:49:07.000000000 +0200 @@ -335,6 +335,7 @@ typedef void (dio_iodone_t)(struct kiocb #define ATTR_KILL_SUID 2048 #define ATTR_KILL_SGID 4096 #define ATTR_FILE 8192 +#define ATTR_OPEN 16384 /* Truncating from open(O_TRUNC) */ /* * This is the Inode Attributes structure, used for notify_change(). It @@ -1521,7 +1522,7 @@ static inline int break_lease(struct ino /* fs/open.c */ -extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs, +extern int do_truncate(struct dentry *, loff_t start, unsigned int attrs, struct file *filp); extern long do_sys_open(int fdf, const char __user *filename, int flags, int mode); Index: linux/fs/open.c =================================================================== --- linux.orig/fs/open.c 2007-08-09 16:48:43.000000000 +0200 +++ linux/fs/open.c 2007-08-09 16:49:07.000000000 +0200 @@ -194,7 +194,7 @@ out: return error; } -int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs, +int do_truncate(struct dentry *dentry, loff_t length, unsigned int attrs, struct file *filp) { int err; @@ -205,7 +205,7 @@ int do_truncate(struct dentry *dentry, l return -EINVAL; newattrs.ia_size = length; - newattrs.ia_valid = ATTR_SIZE | time_attrs; + newattrs.ia_valid = ATTR_SIZE | attrs; if (filp) { newattrs.ia_file = filp; newattrs.ia_valid |= ATTR_FILE; -- - 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/