From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x225qSyMP2JadYBfzz0aryrolbZaP3QBAE4PZuPeK44KLYB9gC4udJ9MURBj2zn4hbOK5uf9m ARC-Seal: i=1; a=rsa-sha256; t=1517256780; cv=none; d=google.com; s=arc-20160816; b=mH4/UmDxbxXQNi84trsRRepjw3vYWE6MAz2WW55qhHUy8AoTx2a6Rtj0+8h570p1wt J2W8Dm2gkMxJ57uwTTEhcCJIj2U04UtICqqcKJpL175CkW+xE4t4FAiWTAKDPxRpr7Iz qSQUFuMejDvpbk3BVxIATz2DFvdLHw+6dh1XrZHPfiZw+fV11oBJHHQGjmoXxU2RvPg+ 1hAOh5JX68mWT3C+n8cjsIQJbc5N6tfoIWwqq32UQoG+muuviD4rsO59rKyYqWuT4YJs pRnqYqE+0DLjW8kkkPziYUAV1HWyK1bvj1GlldGfSR7TN+xT773Sun0wAf17dkLcgf4q fnJg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=GZMYHAkLxRVJV1RGPG4Wf8KXHG4jj1dnEaf7/xsti9o=; b=cTu4Y8qYZCTekK7cyFTOmjCQANlSRZ79WpoN+3o+hdHlwwbZHSL6FPEvjl+N+MyM1y z/lmL7xSUtzGAAZdyV6QhqO8jAxftgH89COGoTG+gFxaQ6JVNX+zmaZvIxu9HpuNz5+Q EeeAqgoHjfzwlQcGH7XcUd0p2xcYAlxCDbOaP4I1ltdnoSi2VitoRSBaPEu5OflAiRNR kP3H5N8qR4EhNDDmTJmOK+491ye9gV0v7fA0MHWroMCOczbBWrkr+u9Ak+3hUgWkjtV0 PZ3Ihx032HsCwYSxOzxJoBkKHPdxm8HUyBe7mTJzdDQ7ij0/tEVWefCiLQ7IFaOXBAjl J5yg== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josef Bacik , David Sterba Subject: [PATCH 4.14 11/71] Btrfs: fix stale entries in readdir Date: Mon, 29 Jan 2018 13:56:39 +0100 Message-Id: <20180129123828.066888632@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180129123827.271171825@linuxfoundation.org> References: <20180129123827.271171825@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1590959045400809110?= X-GMAIL-MSGID: =?utf-8?q?1590959045400809110?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josef Bacik commit e4fd493c0541d36953f7b9d3bfced67a1321792f upstream. In fixing the readdir+pagefault deadlock I accidentally introduced a stale entry regression in readdir. If we get close to full for the temporary buffer, and then skip a few delayed deletions, and then try to add another entry that won't fit, we will emit the entries we found and retry. Unfortunately we delete entries from our del_list as we find them, assuming we won't need them. However our pos will be with whatever our last entry was, which could be before the delayed deletions we skipped, so the next search will add the deleted entries back into our readdir buffer. So instead don't delete entries we find in our del_list so we can make sure we always find our delayed deletions. This is a slight perf hit for readdir with lots of pending deletions, but hopefully this isn't a common occurrence. If it is we can revist this and optimize it. Fixes: 23b5ec74943f ("btrfs: fix readdir deadlock with pagefault") Signed-off-by: Josef Bacik Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/delayed-inode.c | 26 ++++++++------------------ 1 file changed, 8 insertions(+), 18 deletions(-) --- a/fs/btrfs/delayed-inode.c +++ b/fs/btrfs/delayed-inode.c @@ -1677,28 +1677,18 @@ void btrfs_readdir_put_delayed_items(str int btrfs_should_delete_dir_index(struct list_head *del_list, u64 index) { - struct btrfs_delayed_item *curr, *next; - int ret; + struct btrfs_delayed_item *curr; + int ret = 0; - if (list_empty(del_list)) - return 0; - - list_for_each_entry_safe(curr, next, del_list, readdir_list) { + list_for_each_entry(curr, del_list, readdir_list) { if (curr->key.offset > index) break; - - list_del(&curr->readdir_list); - ret = (curr->key.offset == index); - - if (refcount_dec_and_test(&curr->refs)) - kfree(curr); - - if (ret) - return 1; - else - continue; + if (curr->key.offset == index) { + ret = 1; + break; + } } - return 0; + return ret; } /*