From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756695AbYICXFD (ORCPT ); Wed, 3 Sep 2008 19:05:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752607AbYICXEl (ORCPT ); Wed, 3 Sep 2008 19:04:41 -0400 Received: from chmailsrv.int.mrv.com ([66.43.110.11]:25075 "EHLO chmailsrv.int.mrv.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751760AbYICXEk (ORCPT ); Wed, 3 Sep 2008 19:04:40 -0400 Date: Wed, 3 Sep 2008 16:04:30 -0700 From: Nye Liu To: Andrew Morton Cc: Nye Liu , linux-kernel@vger.kernel.org Subject: Re: [PATCH] INITRAMFS: Add option to preserve mtime from INITRAMFS cpio images Message-ID: <20080903230430.GA13874@mrv.com> References: <20080805195232.GA5183@curtisfong.org> <20080903202938.GA9065@curtisfong.org> <20080903152231.6b82d9bf.akpm@linux-foundation.org> <20080903224130.GA16630@curtisfong.org> <20080903154840.69c049cf.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080903154840.69c049cf.akpm@linux-foundation.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-OriginalArrivalTime: 03 Sep 2008 23:06:25.0091 (UTC) FILETIME=[B042D130:01C90E19] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 03, 2008 at 03:48:40PM -0700, Andrew Morton wrote: > On Wed, 3 Sep 2008 15:41:31 -0700 > Nye Liu wrote: > > > > > collected[N_ALIGN(name_len) + body_len] = '\0'; > > > > clean_path(collected, 0); > > > > sys_symlink(collected + N_ALIGN(name_len), collected); > > > > sys_lchown(collected, uid, gid); > > > > + do_lutime(collected, &mtime); > > > > state = SkipIt; > > > > next_state = Reset; > > > > return 0; > > > > @@ -466,6 +520,7 @@ static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only) > > > > buf += inptr; > > > > len -= inptr; > > > > } > > > > + dir_utime(); > > > > > > Perhaps this is the simplest implementation - I didn't check the fine > > > details. What's your thinking here? > > > > > > > The main problem is that i need to save off the entire list for later > > processing of the directory mtimes... if i process the directory mtimes > > in the same pass as the file/link mtimes, touching the directory inode > > when creating/modifying the file/links updates the directory mtime, and > > overwrites whatever mtime i set the directory to when i created it. > > > > The only solution is to do a two pass, which is why the list is > > necessary. If there is a better way, i did not find it :( > > > > It could be that i misunderstood your question though :) > > I'm wondering whether this code need to use `struct utimbuf' at all. > Or at least, as much as it does. utimbuf is more a userspace-facing > thing whereas in-kernel timespecs and timevals are more common. > > The code as you have it does a fair few conversions into utimbuf format > (both directly and via the existing functions which it calls). Would > it be simpler if it dealt in terms of timespecs? > or maybe this, this one ONLY using do_utimes() and a single wrapper to convert the time_t diff --git a/init/initramfs.c b/init/initramfs.c index 644fc01..1360a67 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -6,6 +6,7 @@ #include #include #include +#include static __initdata char *message; static void __init error(char *x) @@ -72,6 +73,51 @@ static void __init free_hash(void) } } +static long __init do_utime(char __user *filename, + time_t mtime) +{ + struct timespec t[2]; + + t[0].tv_sec = mtime; + t[0].tv_nsec = 0; + t[1].tv_sec = mtime; + t[1].tv_nsec = 0; + + return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW); +} + +static __initdata LIST_HEAD(dir_list); +struct dir_entry { + struct list_head list; + char *name; + time_t mtime; +}; + +static void __init dir_add(const char *name, time_t mtime) +{ + struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL); + if (!de) + panic("can't allocate dir_entry buffer"); + INIT_LIST_HEAD(&de->list); + de->name = kstrdup(name, GFP_KERNEL); + de->mtime = mtime; + list_add(&de->list, &dir_list); +} + +static void __init dir_utime(void) +{ + struct list_head *e, *tmp; + list_for_each_safe(e, tmp, &dir_list) { + struct dir_entry *de = list_entry(e, struct dir_entry, list); + list_del(e); + do_utime(de->name, de->mtime); + kfree(de->name); + kfree(de); + } +} + +static __initdata time_t mtime; + /* cpio header parsing */ static __initdata unsigned long ino, major, minor, nlink; @@ -97,6 +143,7 @@ static void __init parse_header(char *s) uid = parsed[2]; gid = parsed[3]; nlink = parsed[4]; + mtime = parsed[5]; body_len = parsed[6]; major = parsed[7]; minor = parsed[8]; @@ -130,6 +177,7 @@ static inline void __init eat(unsigned n) count -= n; } +static __initdata char *vcollected; static __initdata char *collected; static __initdata int remains; static __initdata char *collect; @@ -271,6 +319,7 @@ static int __init do_name(void) if (wfd >= 0) { sys_fchown(wfd, uid, gid); sys_fchmod(wfd, mode); + vcollected = kstrdup(collected, GFP_KERNEL); state = CopyFile; } } @@ -278,12 +327,14 @@ static int __init do_name(void) sys_mkdir(collected, mode); sys_chown(collected, uid, gid); sys_chmod(collected, mode); + dir_add(collected, mtime); } else if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { if (maybe_link() == 0) { sys_mknod(collected, mode, rdev); sys_chown(collected, uid, gid); sys_chmod(collected, mode); + do_utime(collected, mtime); } } return 0; @@ -294,6 +345,8 @@ static int __init do_copy(void) if (count >= body_len) { sys_write(wfd, victim, body_len); sys_close(wfd); + do_utime(vcollected, mtime); + kfree(vcollected); eat(body_len); state = SkipIt; return 0; @@ -311,6 +364,7 @@ static int __init do_symlink(void) clean_path(collected, 0); sys_symlink(collected + N_ALIGN(name_len), collected); sys_lchown(collected, uid, gid); + do_utime(collected, mtime); state = SkipIt; next_state = Reset; return 0; @@ -466,6 +520,7 @@ static char * __init unpack_to_rootfs(char *buf, unsigned len, int check_only) buf += inptr; len -= inptr; } + dir_utime(); kfree(window); kfree(name_buf); kfree(symlink_buf); -- Nye Liu nliu@mrv.com (818) 772-6235x248 (818) 772-0576 fax "Who would be stupid enough to quote a fictitious character?" -- Don Quixote