From: Al Viro <viro@ZenIV.linux.org.uk>
To: NeilBrown <neilb@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
David Herrmann <dh.herrmann@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
David Howells <dhowells@redhat.com>,
Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH] fs: fix i_writecount on shmem and friends
Date: Thu, 13 Mar 2014 04:29:34 +0000 [thread overview]
Message-ID: <20140313042934.GM18016@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20140313150800.07878c80@notabene.brown>
On Thu, Mar 13, 2014 at 03:08:00PM +1100, NeilBrown wrote:
> + inode = mddev->bitmap_info.file->f_mapping->host;
> + if (!S_ISREG(inode->i_mode)) {
> + printk(KERN_ERR "%s: error: bitmap file must be a regular file\n",
> + mdname(mddev));
> + fput(mddev->bitmap_info.file);
> + mddev->bitmap_info.file = NULL;
> + return -EBADF;
> + }
> + if (atomic_read(&inode->i_writecount) != 1) {
Umm... I think you ought to check more than that. At the very least you
want to check that you have it opened for write - you don't want e.g.
a filesystem containing that puppy remounted r/o under you. Another thing
is, what happens if it's not a buffer cache backed one? Hell, what happens
if it's a file on NFS? You are relying on bmap() working, right? So it
looks like you ought to check if ->bmap() is there. And I really wonder
how well does it play with journalling fs...
next prev parent reply other threads:[~2014-03-13 4:29 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-03 15:16 David Herrmann
2014-03-11 19:05 ` Linus Torvalds
2014-03-12 18:19 ` Al Viro
2014-03-12 22:30 ` David Herrmann
2014-03-13 0:37 ` Al Viro
2014-03-13 11:03 ` David Herrmann
2014-03-20 11:13 ` David Herrmann
2014-03-13 4:08 ` NeilBrown
2014-03-13 4:29 ` Al Viro [this message]
2014-03-13 5:55 ` NeilBrown
2014-03-14 4:51 ` Al Viro
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