From: Theodore Tso Subject: Re: [PATCH] ext4: fix #11321: create /proc/ext4/*/stats et al more carefully Date: Mon, 8 Sep 2008 10:39:51 -0400 Message-ID: <20080908143951.GH8161@mit.edu> References: <20080905210652.GE11569@x200.localdomain> <20080906075713.GM3086@webber.adilger.int> <20080907121557.GA3432@x200.localdomain> <20080907160414.GB26248@charite.de> <20080905210652.GE11569@x200.localdomain> <20080906075713.GM3086@webber.adilger.int> <20080907121557.GA3432@x200.localdomain> <20080907162447.GB32429@mit.edu> <20080907164130.GA3376@x200.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ralf Hildebrandt , Andreas Dilger , akpm@osdl.org, linux-ext4@vger.kernel.org To: Alexey Dobriyan Return-path: Received: from BISCAYNE-ONE-STATION.MIT.EDU ([18.7.7.80]:39468 "EHLO biscayne-one-station.mit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751853AbYIHOkM (ORCPT ); Mon, 8 Sep 2008 10:40:12 -0400 Content-Disposition: inline In-Reply-To: <20080907164130.GA3376@x200.localdomain> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sun, Sep 07, 2008 at 08:41:30PM +0400, Alexey Dobriyan wrote: > > register_disk() uses '!' too, BTW. > Yeah, I guess it's good to be consistent with what's being broadcast via udev et al. I still that '!' in pathnames or '/' in device names is really gross and shows no taste, though. :-) Here's what I've checked into the ext4 patch queue for submission to mainline at the next merge window. I've added a bit more error checking in case proc_mkdir() fails and returns NULL. - Ted ext4: fix #11321: create /proc/ext4/*/stats more carefully From: Alexey Dobriyan ext4 creates per-suberblock directory in /proc/ext4/ . Name used as basis is taken from bdevname, which, surprise, can contain slash. However, proc while allowing to use proc_create("a/b", parent) form of PDE creation, assumes that parent/a was already created. bdevname in question is 'cciss/c0d0p9', directory is not created and all this stuff goes directly into /proc (which is real bug). Warning comes when _second_ partition is mounted. http://bugzilla.kernel.org/show_bug.cgi?id=11321 Signed-off-by: Alexey Dobriyan Signed-off-by: "Theodore Ts'o" --- diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 2721643..984144d 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2785,14 +2785,19 @@ static int ext4_mb_init_per_dev_proc(struct super_block *sb) mode_t mode = S_IFREG | S_IRUGO | S_IWUSR; struct ext4_sb_info *sbi = EXT4_SB(sb); struct proc_dir_entry *proc; - char devname[64]; + char devname[64], *p; if (proc_root_ext4 == NULL) { sbi->s_mb_proc = NULL; return -EINVAL; } bdevname(sb->s_bdev, devname); + while (p = strchr(p, '/')) + *p = '!'; + sbi->s_mb_proc = proc_mkdir(devname, proc_root_ext4); + if (!sbi->s_mb_proc) + goto err_create_dir; MB_PROC_HANDLER(EXT4_MB_STATS_NAME, stats); MB_PROC_HANDLER(EXT4_MB_MAX_TO_SCAN_NAME, max_to_scan); @@ -2804,7 +2809,6 @@ static int ext4_mb_init_per_dev_proc(struct super_block *sb) return 0; err_out: - printk(KERN_ERR "EXT4-fs: Unable to create %s\n", devname); remove_proc_entry(EXT4_MB_GROUP_PREALLOC, sbi->s_mb_proc); remove_proc_entry(EXT4_MB_STREAM_REQ, sbi->s_mb_proc); remove_proc_entry(EXT4_MB_ORDER2_REQ, sbi->s_mb_proc); @@ -2813,6 +2817,8 @@ err_out: remove_proc_entry(EXT4_MB_STATS_NAME, sbi->s_mb_proc); remove_proc_entry(devname, proc_root_ext4); sbi->s_mb_proc = NULL; +err_create_dir: + printk(KERN_ERR "EXT4-fs: Unable to create %s\n", devname); return -ENOMEM; }