Some overlayfs mount options cannot be changed via remount,
but remount operation does not return proper error even if
we specify different value to unchangeable options.
This patch add option parsing support for remount so we can
recogonize unchangeable options in remount.
Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx>
---
fs/overlayfs/super.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 7c24619..5c8944b 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -446,14 +446,10 @@ static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode)
return 0;
}
-static int ovl_parse_opt(char *opt, struct ovl_config *config)
+static int ovl_parse_opt(char *opt, struct ovl_config *config, bool remount)
{
char *p;
- config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL);
- if (!config->redirect_mode)
- return -ENOMEM;
-
while ((p = ovl_next_opt(&opt)) != NULL) {
int token;
substring_t args[MAX_OPT_ARGS];
@@ -517,6 +513,9 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
}
}
+ if (remount)
+ return 0;
+
/* Workdir is useless in non-upper mount */
if (!config->upperdir && config->workdir) {
pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n",
@@ -525,6 +524,13 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
config->workdir = NULL;
}
+ if (!config->redirect_mode) {
+ config->redirect_mode = kstrdup(ovl_redirect_mode_def(),
+ GFP_KERNEL);
+ if (!config->redirect_mode)
+ return -ENOMEM;
+ }
+
return ovl_parse_redirect_mode(config, config->redirect_mode);
}
@@ -1250,6 +1256,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
struct ovl_entry *oe;
struct ovl_fs *ofs;
struct cred *cred;
+ bool remount = false;
int err;
err = -ENOMEM;
@@ -1263,7 +1270,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
ofs->config.index = ovl_index_def;
ofs->config.nfs_export = ovl_nfs_export_def;
- err = ovl_parse_opt((char *) data, &ofs->config);
+ err = ovl_parse_opt((char *) data, &ofs->config, remount);
if (err)
goto out_err;
--
1.8.3.1
--
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