Re: [PATCH 2/2] jffs2: fix can't set rp_size to zero during remounting

From: Zhe Li
Date: Wed Nov 18 2020 - 22:01:30 EST


Maintainer ping?

Zhe

On Tue, 13 Oct 2020 19:41:30 +0800, Zhe Li wrote:
>
>Set rp_size to zero will be ignore during remounting.
>
>The method to identify whether we input a remounting option of
>rp_size is to check if the rp_size input is zero. It can not work
>well if we pass "rp_size=0".
>
>This patch add a bool variable "set_rp_size" to fix this problem.
>
>By the way, the problem of NULL pointer dereference in rp_size
>fs option parsing showed at
>https://lore.kernel.org/linux-mtd/20201012131204.59102-1-jamie@xxxxxxxxxxxx/T/#u
>should be applyed before this patch to make sure it works well.
>
>Reported-by: Jubin Zhong <zhongjubin@xxxxxxxxxx>
>Signed-off-by: lizhe <lizhe67@xxxxxxxxxx>
>---
> fs/jffs2/jffs2_fs_sb.h | 1 +
> fs/jffs2/super.c | 7 +++++--
> 2 files changed, 6 insertions(+), 2 deletions(-)
>
>diff --git a/fs/jffs2/jffs2_fs_sb.h b/fs/jffs2/jffs2_fs_sb.h
>index 778275f48a87..5a7091746f68 100644
>--- a/fs/jffs2/jffs2_fs_sb.h
>+++ b/fs/jffs2/jffs2_fs_sb.h
>@@ -38,6 +38,7 @@ struct jffs2_mount_opts {
> * users. This is implemented simply by means of not allowing the
> * latter users to write to the file system if the amount if the
> * available space is less then 'rp_size'. */
>+ bool set_rp_size;
> unsigned int rp_size;
> };
>
>diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
>index 4fd297bdf0f3..c523adaca79f 100644
>--- a/fs/jffs2/super.c
>+++ b/fs/jffs2/super.c
>@@ -88,7 +88,7 @@ static int jffs2_show_options(struct seq_file *s, struct dentry *root)
>
> if (opts->override_compr)
> seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
>- if (opts->rp_size)
>+ if (opts->set_rp_size)
> seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);
>
> return 0;
>@@ -206,6 +206,7 @@ static int jffs2_parse_param(struct fs_context *fc, struct fs_parameter *param)
> if (opt > c->mtd->size)
> return invalf(fc, "jffs2: Too large reserve pool specified, max is %llu KB",
> c->mtd->size / 1024);
>+ c->mount_opts.set_rp_size = true;
> c->mount_opts.rp_size = opt;
> break;
> default:
>@@ -225,8 +226,10 @@ static inline void jffs2_update_mount_opts(struct fs_context *fc)
> c->mount_opts.override_compr = new_c->mount_opts.override_compr;
> c->mount_opts.compr = new_c->mount_opts.compr;
> }
>- if (new_c->mount_opts.rp_size)
>+ if (new_c->mount_opts.set_rp_size) {
>+ c->mount_opts.set_rp_size = new_c->mount_opts.set_rp_size;
> c->mount_opts.rp_size = new_c->mount_opts.rp_size;
>+ }
> mutex_unlock(&c->alloc_sem);
> }
>
>--
>2.12.3
>