Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758690AbXKAXIt (ORCPT ); Thu, 1 Nov 2007 19:08:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753619AbXKAXIg (ORCPT ); Thu, 1 Nov 2007 19:08:36 -0400 Received: from e34.co.us.ibm.com ([32.97.110.152]:44340 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752611AbXKAXIf (ORCPT ); Thu, 1 Nov 2007 19:08:35 -0400 Subject: [PATCH 02/27] make open_namei() return a filp To: akpm@osdl.org Cc: linux-kernel@vger.kernel.org, miklos@szeredi.hu, hch@infradead.org, Dave Hansen From: Dave Hansen Date: Thu, 01 Nov 2007 16:08:28 -0700 References: <20071101230826.9A4F6E00@kernel> In-Reply-To: <20071101230826.9A4F6E00@kernel> Message-Id: <20071101230828.B1162D60@kernel> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4606 Lines: 133 open_namei() will, in the future, need to take mount write counts over its creation and truncation (via may_open()) operations. It needs to keep these write counts until any potential filp that is created gets __fput()'d. This gets complicated in the error handling and becomes very murky as to how far open_namei() actually got, and whether or not that mount write count was taken. Creating the filps inside of open_namei() lets us shift the write count to be taken and released along with the filp. We can hold a temporary write count during those creation and truncation operations, then release them once the write for the filp has been established. Any caller who gets a 'struct file' back must consider that filp instantiated and fput() it normally. The callers no longer have to worry about ever manually releasing a mnt write count. Signed-off-by: Dave Hansen --- linux-2.6.git-dave/fs/namei.c | 16 ++++++++-------- linux-2.6.git-dave/fs/open.c | 7 +------ linux-2.6.git-dave/include/linux/fs.h | 2 +- 3 files changed, 10 insertions(+), 15 deletions(-) diff -puN fs/namei.c~make-open_namei-return-a-filp fs/namei.c --- linux-2.6.git/fs/namei.c~make-open_namei-return-a-filp 2007-11-01 14:46:05.000000000 -0700 +++ linux-2.6.git-dave/fs/namei.c 2007-11-01 14:46:05.000000000 -0700 @@ -1730,8 +1730,8 @@ static inline int sys_open_flags_to_name * system call. See sys_open_flags_to_namei_flags(). * SMP-safe */ -int open_namei(int dfd, const char *pathname, int sys_open_flag, - int mode, struct nameidata *nd) +struct file *open_namei(int dfd, const char *pathname, int sys_open_flag, + int mode, struct nameidata *nd) { int acc_mode, error; struct path path; @@ -1757,7 +1757,7 @@ int open_namei(int dfd, const char *path error = path_lookup_open(dfd, pathname, lookup_flags(flag), nd, flag); if (error) - return error; + return ERR_PTR(error); goto ok; } @@ -1766,7 +1766,7 @@ int open_namei(int dfd, const char *path */ error = path_lookup_create(dfd,pathname,LOOKUP_PARENT,nd,flag,mode); if (error) - return error; + return ERR_PTR(error); /* * We have the parent and last component. First of all, check @@ -1801,7 +1801,7 @@ do_last: error = __open_namei_create(nd, &path, flag, mode); if (error) goto exit; - return 0; + return nameidata_to_filp(nd, sys_open_flag); } /* @@ -1834,7 +1834,7 @@ ok: error = may_open(nd, acc_mode, flag); if (error) goto exit; - return 0; + return nameidata_to_filp(nd, sys_open_flag); exit_dput: dput_path(&path, nd); @@ -1842,7 +1842,7 @@ exit: if (!IS_ERR(nd->intent.open.file)) release_open_intent(nd); path_release(nd); - return error; + return ERR_PTR(error); do_link: error = -ELOOP; @@ -1869,7 +1869,7 @@ do_link: * with "intent.open". */ release_open_intent(nd); - return error; + return ERR_PTR(error); } nd->flags &= ~LOOKUP_PARENT; if (nd->last_type == LAST_BIND) diff -puN fs/open.c~make-open_namei-return-a-filp fs/open.c --- linux-2.6.git/fs/open.c~make-open_namei-return-a-filp 2007-11-01 14:46:05.000000000 -0700 +++ linux-2.6.git-dave/fs/open.c 2007-11-01 14:46:05.000000000 -0700 @@ -803,14 +803,9 @@ cleanup_file: static struct file *do_filp_open(int dfd, const char *filename, int flags, int mode) { - int error; struct nameidata nd; - error = open_namei(dfd, filename, flags, mode, &nd); - if (!error) - return nameidata_to_filp(&nd, flags); - - return ERR_PTR(error); + return open_namei(dfd, filename, flags, mode, &nd); } struct file *filp_open(const char *filename, int flags, int mode) diff -puN include/linux/fs.h~make-open_namei-return-a-filp include/linux/fs.h --- linux-2.6.git/include/linux/fs.h~make-open_namei-return-a-filp 2007-11-01 14:46:05.000000000 -0700 +++ linux-2.6.git-dave/include/linux/fs.h 2007-11-01 14:46:05.000000000 -0700 @@ -1714,7 +1714,7 @@ extern struct file *create_read_pipe(str extern struct file *create_write_pipe(void); extern void free_write_pipe(struct file *); -extern int open_namei(int dfd, const char *, int, int, struct nameidata *); +extern struct file *open_namei(int dfd, const char *, int, int, struct nameidata *); extern int may_open(struct nameidata *, int, int); extern int kernel_read(struct file *, unsigned long, char *, unsigned long); _ - 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/