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path: root/fs/overlayfs/super.c
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Diffstat (limited to 'fs/overlayfs/super.c')
-rw-r--r--fs/overlayfs/super.c87
1 files changed, 66 insertions, 21 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 288d20f9a55a..76440feb79f6 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -33,6 +33,13 @@ module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644);
MODULE_PARM_DESC(ovl_redirect_dir_def,
"Default to on or off for the redirect_dir feature");
+static bool ovl_redirect_always_follow =
+ IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW);
+module_param_named(redirect_always_follow, ovl_redirect_always_follow,
+ bool, 0644);
+MODULE_PARM_DESC(ovl_redirect_always_follow,
+ "Follow redirects even if redirect_dir feature is turned off");
+
static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX);
module_param_named(index, ovl_index_def, bool, 0644);
MODULE_PARM_DESC(ovl_index_def,
@@ -232,6 +239,7 @@ static void ovl_free_fs(struct ovl_fs *ofs)
kfree(ofs->config.lowerdir);
kfree(ofs->config.upperdir);
kfree(ofs->config.workdir);
+ kfree(ofs->config.redirect_mode);
if (ofs->creator_cred)
put_cred(ofs->creator_cred);
kfree(ofs);
@@ -244,6 +252,7 @@ static void ovl_put_super(struct super_block *sb)
ovl_free_fs(ofs);
}
+/* Sync real dirty inodes in upper filesystem (if it exists) */
static int ovl_sync_fs(struct super_block *sb, int wait)
{
struct ovl_fs *ofs = sb->s_fs_info;
@@ -252,14 +261,24 @@ static int ovl_sync_fs(struct super_block *sb, int wait)
if (!ofs->upper_mnt)
return 0;
- upper_sb = ofs->upper_mnt->mnt_sb;
- if (!upper_sb->s_op->sync_fs)
+
+ /*
+ * If this is a sync(2) call or an emergency sync, all the super blocks
+ * will be iterated, including upper_sb, so no need to do anything.
+ *
+ * If this is a syncfs(2) call, then we do need to call
+ * sync_filesystem() on upper_sb, but enough if we do it when being
+ * called with wait == 1.
+ */
+ if (!wait)
return 0;
- /* real inodes have already been synced by sync_filesystem(ovl_sb) */
+ upper_sb = ofs->upper_mnt->mnt_sb;
+
down_read(&upper_sb->s_umount);
- ret = upper_sb->s_op->sync_fs(upper_sb, wait);
+ ret = sync_filesystem(upper_sb);
up_read(&upper_sb->s_umount);
+
return ret;
}
@@ -295,6 +314,11 @@ static bool ovl_force_readonly(struct ovl_fs *ofs)
return (!ofs->upper_mnt || !ofs->workdir);
}
+static const char *ovl_redirect_mode_def(void)
+{
+ return ovl_redirect_dir_def ? "on" : "off";
+}
+
/**
* ovl_show_options
*
@@ -313,12 +337,10 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
}
if (ofs->config.default_permissions)
seq_puts(m, ",default_permissions");
- if (ofs->config.redirect_dir != ovl_redirect_dir_def)
- seq_printf(m, ",redirect_dir=%s",
- ofs->config.redirect_dir ? "on" : "off");
+ if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0)
+ seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode);
if (ofs->config.index != ovl_index_def)
- seq_printf(m, ",index=%s",
- ofs->config.index ? "on" : "off");
+ seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off");
return 0;
}
@@ -348,8 +370,7 @@ enum {
OPT_UPPERDIR,
OPT_WORKDIR,
OPT_DEFAULT_PERMISSIONS,
- OPT_REDIRECT_DIR_ON,
- OPT_REDIRECT_DIR_OFF,
+ OPT_REDIRECT_DIR,
OPT_INDEX_ON,
OPT_INDEX_OFF,
OPT_ERR,
@@ -360,8 +381,7 @@ static const match_table_t ovl_tokens = {
{OPT_UPPERDIR, "upperdir=%s"},
{OPT_WORKDIR, "workdir=%s"},
{OPT_DEFAULT_PERMISSIONS, "default_permissions"},
- {OPT_REDIRECT_DIR_ON, "redirect_dir=on"},
- {OPT_REDIRECT_DIR_OFF, "redirect_dir=off"},
+ {OPT_REDIRECT_DIR, "redirect_dir=%s"},
{OPT_INDEX_ON, "index=on"},
{OPT_INDEX_OFF, "index=off"},
{OPT_ERR, NULL}
@@ -390,10 +410,37 @@ static char *ovl_next_opt(char **s)
return sbegin;
}
+static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode)
+{
+ if (strcmp(mode, "on") == 0) {
+ config->redirect_dir = true;
+ /*
+ * Does not make sense to have redirect creation without
+ * redirect following.
+ */
+ config->redirect_follow = true;
+ } else if (strcmp(mode, "follow") == 0) {
+ config->redirect_follow = true;
+ } else if (strcmp(mode, "off") == 0) {
+ if (ovl_redirect_always_follow)
+ config->redirect_follow = true;
+ } else if (strcmp(mode, "nofollow") != 0) {
+ pr_err("overlayfs: bad mount option \"redirect_dir=%s\"\n",
+ mode);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int ovl_parse_opt(char *opt, struct ovl_config *config)
{
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];
@@ -428,12 +475,11 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
config->default_permissions = true;
break;
- case OPT_REDIRECT_DIR_ON:
- config->redirect_dir = true;
- break;
-
- case OPT_REDIRECT_DIR_OFF:
- config->redirect_dir = false;
+ case OPT_REDIRECT_DIR:
+ kfree(config->redirect_mode);
+ config->redirect_mode = match_strdup(&args[0]);
+ if (!config->redirect_mode)
+ return -ENOMEM;
break;
case OPT_INDEX_ON:
@@ -458,7 +504,7 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
config->workdir = NULL;
}
- return 0;
+ return ovl_parse_redirect_mode(config, config->redirect_mode);
}
#define OVL_WORKDIR_NAME "work"
@@ -1160,7 +1206,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (!cred)
goto out_err;
- ofs->config.redirect_dir = ovl_redirect_dir_def;
ofs->config.index = ovl_index_def;
err = ovl_parse_opt((char *) data, &ofs->config);
if (err)
generated by cgit (git 2.34.1) at 2024-05-04 22:03:11 +0000