From: Al Viro <viro@ZenIV.linux.org.uk>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
jack@suse.cz, hch@infradead.org, akpm@linux-foundation.org,
toshi.okajima@jp.fujitsu.com, mszeredi@suse.cz
Subject: Re: [PATCH 2/4] vfs: keep list of mounts for each superblock
Date: Wed, 3 Aug 2011 23:17:07 +0100 [thread overview]
Message-ID: <20110803221707.GM2203@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1312368521-7911-3-git-send-email-miklos@szeredi.hu>
On Wed, Aug 03, 2011 at 12:48:39PM +0200, Miklos Szeredi wrote:
> @@ -696,6 +696,11 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
> mnt->mnt_sb = root->d_sb;
> mnt->mnt_mountpoint = mnt->mnt_root;
> mnt->mnt_parent = mnt;
> +
> + br_write_lock(vfsmount_lock);
> + list_add_tail(&mnt->mnt_instance, &mnt->mnt_sb->s_mounts);
> + br_write_unlock(vfsmount_lock);
Racy.
> @@ -745,6 +750,10 @@ static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root,
> if (!list_empty(&old->mnt_expire))
> list_add(&mnt->mnt_expire, &old->mnt_expire);
> }
> +
> + br_write_lock(vfsmount_lock);
> + list_add_tail(&mnt->mnt_instance, &mnt->mnt_sb->s_mounts);
> + br_write_unlock(vfsmount_lock);
Ditto. If you expect to be able to find *all* vfsmounts over given sb,
this locking is simply wrong.
next prev parent reply other threads:[~2011-08-03 22:17 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-03 10:48 [PATCH v5 0/4] read-only remount race fix Miklos Szeredi
2011-08-03 10:48 ` [PATCH 1/4] vfs: ignore error on forced remount Miklos Szeredi
2011-08-03 10:49 ` Christoph Hellwig
2011-08-03 16:15 ` Miklos Szeredi
2011-08-03 10:48 ` [PATCH 2/4] vfs: keep list of mounts for each superblock Miklos Szeredi
2011-08-03 21:53 ` Christoph Hellwig
2011-08-03 22:17 ` Al Viro [this message]
2011-08-04 9:10 ` Miklos Szeredi
2011-08-04 9:46 ` Jan Kara
2011-08-04 9:58 ` Miklos Szeredi
2011-08-03 10:48 ` [PATCH 3/4] vfs: protect remounting superblock read-only Miklos Szeredi
2011-08-03 10:48 ` [PATCH 4/4] vfs: fs_may_remount_ro: turn unnecessary check into a WARN_ON Miklos Szeredi
[not found] <1314191791-29218-1-git-send-email-miklos@szeredi.hu>
2011-08-24 13:22 ` [PATCH 2/4] vfs: keep list of mounts for each superblock Miklos Szeredi
-- strict thread matches above, loose matches on Subject: below --
2010-10-26 14:16 [PATCH 0/4] read-only remount fixes Miklos Szeredi
2010-10-26 14:16 ` [PATCH 2/4] vfs: keep list of mounts for each superblock Miklos Szeredi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20110803221707.GM2203@ZenIV.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=akpm@linux-foundation.org \
--cc=hch@infradead.org \
--cc=jack@suse.cz \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=miklos@szeredi.hu \
--cc=mszeredi@suse.cz \
--cc=toshi.okajima@jp.fujitsu.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).