From: Al Viro <viro@ZenIV.linux.org.uk>
To: Qu Wenruo <quwenruo@cn.fujitsu.com>
Cc: Miao Xie <miaoxie@huawei.com>,
linux-btrfs@vger.kernel.org,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH RESEND v4 6/8] vfs: Add get_vfsmount_sb() function to get vfsmount from a given sb.
Date: Fri, 30 Jan 2015 02:14:45 +0000 [thread overview]
Message-ID: <20150130021445.GH29656@ZenIV.linux.org.uk> (raw)
In-Reply-To: <54CAE1E3.1040406@cn.fujitsu.com>
On Fri, Jan 30, 2015 at 09:44:03AM +0800, Qu Wenruo wrote:
> This shouldn't happen. If someone is ro, the whole fs should be ro, right?
Wrong. Individual vfsmounts over an r/w superblock might very well be r/o.
As for that trylock... What for? It invites transient failures for no
good reason. Removal of sysfs entry will block while write(2) to that sucker
is in progress, so btrfs shutdown will block at that point in ctree_close().
It won't go away under you.
Now, you might want to move those sysfs entry removals to the very beginning
of btrfs_kill_super(), but that's a different story - you need only to make
sure that they are removed not later than the destruction of the data
structures they need (IOW, the current location might very well be OK - I
hadn't checked the details).
As for "it won't go r/o under us" - sb_want_write() will do that just fine.
next prev parent reply other threads:[~2015-01-30 2:14 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1422498281-20493-1-git-send-email-quwenruo@cn.fujitsu.com>
2015-01-29 2:24 ` [PATCH RESEND v4 6/8] vfs: Add get_vfsmount_sb() function to get vfsmount from a given sb Qu Wenruo
2015-01-29 12:37 ` David Sterba
2015-01-29 15:23 ` Al Viro
2015-01-30 1:11 ` Qu Wenruo
2015-01-30 2:09 ` Al Viro
2015-01-30 2:20 ` Qu Wenruo
2015-01-30 0:52 ` Miao Xie
2015-01-30 1:44 ` Qu Wenruo
2015-01-30 2:02 ` Qu Wenruo
2015-01-30 3:22 ` Miao Xie
2015-01-30 3:30 ` Qu Wenruo
2015-01-30 2:14 ` Al Viro [this message]
2015-01-30 4:14 ` Miao Xie
2015-01-30 4:37 ` Al Viro
2015-01-30 5:34 ` Miao Xie
2015-01-30 6:15 ` Al Viro
2015-01-30 5:30 ` Qu Wenruo
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