From: Andi Kleen <andi@firstfloor.org>
To: Nick Piggin <npiggin@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>, linux-fsdevel@vger.kernel.org
Subject: Re: [patch 01/10] fs: fix do_lookup false negative
Date: Wed, 18 Aug 2010 15:41:02 +0200 [thread overview]
Message-ID: <87mxskkpht.fsf@basil.nowhere.org> (raw)
In-Reply-To: <20100817184120.128470975@kernel.dk> (Nick Piggin's message of "Wed, 18 Aug 2010 04:37:30 +1000")
Nick Piggin <npiggin@kernel.dk> writes:
> fs: fix do_lookup false negative
>
> In do_lookup, if we initially find no dentry, we take the directory i_mutex and
> re-check the lookup. If we find a dentry there, then we revalidate it if
> needed. However if that revalidate asks for the dentry to be invalidated, we
> return -ENOENT from do_lookup. What should happen instead is an attempt to
> allocate and lookup a new dentry.
>
> This is probably not noticed because it is rare. It is only reached if a
> concurrent create races in first (in which case, the dentry probably won't be
> invalidated anyway), or if the racy __d_lookup has failed due to a
> false-negative (which is very rare).
>
> Fix this by removing code and have it use the normal reval path.
Looks good, but a comment would be good.
Reviewed-by: Andi Kleen <ak@linux.intel.com>
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2010-08-18 13:41 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-17 18:37 [patch 00/10] first set of vfs scale patches Nick Piggin
2010-08-17 18:37 ` [patch 01/10] fs: fix do_lookup false negative Nick Piggin
2010-08-17 22:45 ` Valerie Aurora
2010-08-17 23:04 ` Sage Weil
2010-08-18 13:41 ` Andi Kleen [this message]
2010-08-17 18:37 ` [patch 02/10] fs: dentry allocation consolidation Nick Piggin
2010-08-17 22:45 ` Valerie Aurora
2010-08-17 18:37 ` [patch 03/10] apparmor: use task path helpers Nick Piggin
2010-08-17 22:59 ` Valerie Aurora
2010-08-17 18:37 ` [patch 04/10] fs: fs_struct rwlock to spinlock Nick Piggin
2010-08-17 23:14 ` Valerie Aurora
2010-08-20 10:05 ` Nick Piggin
2010-08-17 18:37 ` [patch 05/10] fs: remove extra lookup in __lookup_hash Nick Piggin
2010-08-18 13:57 ` Andi Kleen
2010-08-18 21:13 ` Andi Kleen
2010-08-18 19:34 ` Valerie Aurora
2010-08-17 18:37 ` [patch 06/10] fs: cleanup files_lock locking Nick Piggin
2010-08-18 19:46 ` Valerie Aurora
2010-08-17 18:37 ` [patch 07/10] tty: fix fu_list abuse Nick Piggin
2010-08-17 18:37 ` [patch 08/10] lglock: introduce special lglock and brlock spin locks Nick Piggin
2010-08-17 18:37 ` [patch 09/10] fs: scale files_lock Nick Piggin
2010-08-17 18:37 ` [patch 10/10] fs: brlock vfsmount_lock Nick Piggin
2010-08-18 14:05 ` Andi Kleen
2010-08-20 10:09 ` Nick Piggin
2010-08-17 21:14 ` [patch 00/10] first set of vfs scale patches Al Viro
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