From: Tejun Heo <tj@kernel.org>
To: gregkh@linuxfoundation.org
Cc: kernel-team@fb.com, linux-kernel@vger.kernel.org,
cgroups@vger.kernel.org, lizefan@huawei.com, hannes@cmpxchg.org,
namhyung@kernel.org, ast@kernel.org, daniel@iogearbox.net,
Tejun Heo <tj@kernel.org>,
stable@vger.kernel.org
Subject: [PATCH 01/10] kernfs: fix ino wrap-around detection
Date: Mon, 4 Nov 2019 15:59:35 -0800 [thread overview]
Message-ID: <20191104235944.3470866-2-tj@kernel.org> (raw)
In-Reply-To: <20191104235944.3470866-1-tj@kernel.org>
When the 32bit ino wraps around, kernfs increments the generation
number to distinguish reused ino instances. The wrap-around detection
tests whether the allocated ino is lower than what the cursor but the
cursor is pointing to the next ino to allocate so the condition never
triggers.
Fix it by remembering the last ino and comparing against that.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 4a3ef68acacf ("kernfs: implement i_generation")
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: stable@vger.kernel.org # v4.14+
---
fs/kernfs/dir.c | 5 ++---
include/linux/kernfs.h | 1 +
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 6ebae6bbe6a5..7d4af6cea2a6 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -622,7 +622,6 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
{
struct kernfs_node *kn;
u32 gen;
- int cursor;
int ret;
name = kstrdup_const(name, GFP_KERNEL);
@@ -635,11 +634,11 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
idr_preload(GFP_KERNEL);
spin_lock(&kernfs_idr_lock);
- cursor = idr_get_cursor(&root->ino_idr);
ret = idr_alloc_cyclic(&root->ino_idr, kn, 1, 0, GFP_ATOMIC);
- if (ret >= 0 && ret < cursor)
+ if (ret >= 0 && ret < root->last_ino)
root->next_generation++;
gen = root->next_generation;
+ root->last_ino = ret;
spin_unlock(&kernfs_idr_lock);
idr_preload_end();
if (ret < 0)
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 936b61bd504e..f797ccc650e7 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -187,6 +187,7 @@ struct kernfs_root {
/* private fields, do not use outside kernfs proper */
struct idr ino_idr;
+ u32 last_ino;
u32 next_generation;
struct kernfs_syscall_ops *syscall_ops;
--
2.17.1
next prev parent reply other threads:[~2019-11-04 23:59 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-04 23:59 [PATCHSET cgroup/for-5.5] kernfs,cgroup: support 64bit inos and unify cgroup IDs Tejun Heo
2019-11-04 23:59 ` Tejun Heo [this message]
2019-11-04 23:59 ` [PATCH 02/10] writeback: use ino_t for inodes in tracepoints Tejun Heo
2019-11-05 9:11 ` Jan Kara
2019-11-04 23:59 ` [PATCH 03/10] netprio: use css ID instead of cgroup ID Tejun Heo
2019-11-05 13:27 ` Neil Horman
2019-11-04 23:59 ` [PATCH 04/10] kernfs: use dumber locking for kernfs_find_and_get_node_by_ino() Tejun Heo
2019-11-04 23:59 ` [PATCH 05/10] kernfs: kernfs_find_and_get_node_by_ino() should only look up activated nodes Tejun Heo
2019-11-04 23:59 ` [PATCH 06/10] kernfs: convert kernfs_node->id from union kernfs_node_id to u64 Tejun Heo
2019-11-04 23:59 ` [PATCH 07/10] kernfs: combine ino/id lookup functions into kernfs_find_and_get_node_by_id() Tejun Heo
2019-11-04 23:59 ` [PATCH 08/10] kernfs: implement custom exportfs ops and fid type Tejun Heo
2019-11-04 23:59 ` [PATCH 09/10] kernfs: use 64bit inos if ino_t is 64bit Tejun Heo
2019-11-04 23:59 ` [PATCH 10/10] cgroup: use cgrp->kn->id as the cgroup ID Tejun Heo
2019-11-06 13:50 ` [PATCHSET cgroup/for-5.5] kernfs,cgroup: support 64bit inos and unify cgroup IDs Namhyung Kim
2019-11-07 15:31 ` Tejun Heo
2019-11-12 15:51 ` Tejun Heo
2019-11-12 16:08 ` Greg KH
2019-11-12 16:09 ` Greg KH
2019-11-12 16:19 ` Tejun Heo
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