Do all the logic to set the mode during mount options parsing and
do not keep the option string around.
This results in a minor change to the string that is displayed
in show_options() - when CONFIG_OVERLAY_FS_REDIRECT_DIR=y and the user
mounts with the option "redirect_dir=off", instead of displaying the mode
"redirect_dir=off" in show_options(), the displayed mode will be either
"redirect_dir=follow" or "redirect_dir=nofollow", depending on the value
of CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW.
The displayed mode reflects the effective mode, so mounting overlayfs
again with the dispalyed redirect_dir option will result in the sam
effective and displayed mode.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/dir.c | 2 +-
fs/overlayfs/namei.c | 6 +-
fs/overlayfs/overlayfs.h | 20 +++++-
fs/overlayfs/ovl_entry.h | 4 +-
fs/overlayfs/super.c | 148 ++++++++++++++++++++++-----------------
fs/overlayfs/util.c | 7 --
6 files changed, 107 insertions(+), 80 deletions(-)
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 92bdcedfaaec..e7e30a999fac 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -952,7 +952,7 @@ static bool ovl_type_merge_or_lower(struct dentry *dentry)
static bool ovl_can_move(struct dentry *dentry)
{
- return ovl_redirect_dir(dentry->d_sb) ||
+ return ovl_redirect_dir(OVL_FS(dentry->d_sb)) ||
!d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry);
}
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 292b8a948f1a..288e3c0ee0e6 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -961,7 +961,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
.is_dir = false,
.opaque = false,
.stop = false,
- .last = ofs->config.redirect_follow ? false : !ovl_numlower(poe),
+ .last = ovl_redirect_follow(ofs) ? false : !ovl_numlower(poe),
.redirect = NULL,
.metacopy = false,
};
@@ -1022,7 +1022,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
for (i = 0; !d.stop && i < ovl_numlower(poe); i++) {
struct ovl_path lower = ovl_lowerstack(poe)[i];
- if (!ofs->config.redirect_follow)
+ if (!ovl_redirect_follow(ofs))
d.last = i == ovl_numlower(poe) - 1;
else if (d.is_dir || !ofs->numdatalayer)
d.last = lower.layer->idx == ovl_numlower(roe);
@@ -1102,7 +1102,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
* this attack vector when not necessary.
*/
err = -EPERM;
- if (d.redirect && !ofs->config.redirect_follow) {
+ if (d.redirect && !ovl_redirect_follow(ofs)) {
pr_warn_ratelimited("refusing to follow redirect for (%pd2)\n",
dentry);
goto out_put;
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index fcac4e2c56ab..e689520e3eca 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -57,6 +57,13 @@ enum ovl_entry_flag {
OVL_E_CONNECTED,
};
+enum {
+ OVL_REDIRECT_ON,
+ OVL_REDIRECT_OFF, /* "off" mode is never used... */
+ OVL_REDIRECT_FOLLOW, /* ...it translates to either "follow" */
+ OVL_REDIRECT_NOFOLLOW, /* ...or "nofollow". */
+};
+
enum {
OVL_XINO_OFF,
OVL_XINO_AUTO,
@@ -352,6 +359,16 @@ static inline bool ovl_open_flags_need_copy_up(int flags)
return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
}
+static inline bool ovl_redirect_follow(struct ovl_fs *ofs)
+{
+ return ofs->config.redirect_mode != OVL_REDIRECT_NOFOLLOW;
+}
+
+static inline bool ovl_redirect_dir(struct ovl_fs *ofs)
+{
+ return ofs->config.redirect_mode == OVL_REDIRECT_ON;
+}
+
static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
{
/*
@@ -360,7 +377,7 @@ static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
* are used.
*/
return (!ofs->config.index && !ofs->config.metacopy &&
- !ofs->config.redirect_dir && ofs->config.xino != OVL_XINO_ON);
+ !ovl_redirect_dir(ofs) && ofs->config.xino != OVL_XINO_ON);
}
@@ -421,7 +438,6 @@ bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
bool ovl_has_upperdata(struct inode *inode);
void ovl_set_upperdata(struct inode *inode);
-bool ovl_redirect_dir(struct super_block *sb);
const char *ovl_dentry_get_redirect(struct dentry *dentry);
void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index e5207c4bf5b8..0ff12622ac1b 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -10,9 +10,7 @@ struct ovl_config {
char *upperdir;
char *workdir;
bool default_permissions;
- bool redirect_dir;
- bool redirect_follow;
- const char *redirect_mode;
+ int redirect_mode;
bool index;
bool uuid;
bool nfs_export;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 14a2ebdc8126..cc7d7d8af711 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -16,6 +16,7 @@
#include <linux/posix_acl_xattr.h>
#include <linux/exportfs.h>
#include <linux/file.h>
+#include <linux/fs_parser.h>
#include "overlayfs.h"
MODULE_AUTHOR("Miklos Szeredi <miklos@xxxxxxxxxx>");
@@ -243,7 +244,6 @@ 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);
@@ -329,17 +329,38 @@ static bool ovl_force_readonly(struct ovl_fs *ofs)
return (!ovl_upper_mnt(ofs) || !ofs->workdir);
}
-static const char *ovl_redirect_mode_def(void)
+static const struct constant_table ovl_parameter_redirect_dir[] = {
+ { "on", OVL_REDIRECT_ON },
+ { "off", OVL_REDIRECT_OFF },
+ { "follow", OVL_REDIRECT_FOLLOW },
+ { "nofollow", OVL_REDIRECT_NOFOLLOW },
+ {}
+};
+
+static const char *ovl_redirect_mode(struct ovl_config *config)
+{
+ return ovl_parameter_redirect_dir[config->redirect_mode].name;
+}
+
+static int ovl_redirect_mode_def(void)
{
- return ovl_redirect_dir_def ? "on" : "off";
+ return ovl_redirect_dir_def ? OVL_REDIRECT_ON :
+ ovl_redirect_always_follow ? OVL_REDIRECT_FOLLOW :
+ OVL_REDIRECT_NOFOLLOW;
}
-static const char * const ovl_xino_str[] = {
- "off",
- "auto",
- "on",
+static const struct constant_table ovl_parameter_xino[] = {
+ { "on", OVL_XINO_ON },
+ { "off", OVL_XINO_OFF },
+ { "auto", OVL_XINO_AUTO },
+ {}
};
+static const char *ovl_xino_mode(struct ovl_config *config)
+{
+ return ovl_parameter_xino[config->xino].name;
+}
+
static inline int ovl_xino_def(void)
{
return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF;
@@ -365,8 +386,9 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
}
if (ofs->config.default_permissions)
seq_puts(m, ",default_permissions");
- if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0)
- seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode);
+ if (ofs->config.redirect_mode != ovl_redirect_mode_def())
+ seq_printf(m, ",redirect_dir=%s",
+ ovl_redirect_mode(&ofs->config));
if (ofs->config.index != ovl_index_def)
seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off");
if (!ofs->config.uuid)
@@ -375,7 +397,7 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ?
"on" : "off");
if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(sb))
- seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]);
+ seq_printf(m, ",xino=%s", ovl_xino_mode(&ofs->config));
if (ofs->config.metacopy != ovl_metacopy_def)
seq_printf(m, ",metacopy=%s",
ofs->config.metacopy ? "on" : "off");
@@ -424,7 +446,10 @@ enum {
OPT_UPPERDIR,
OPT_WORKDIR,
OPT_DEFAULT_PERMISSIONS,
- OPT_REDIRECT_DIR,
+ OPT_REDIRECT_DIR_ON,
+ OPT_REDIRECT_DIR_OFF,
+ OPT_REDIRECT_DIR_FOLLOW,
+ OPT_REDIRECT_DIR_NOFOLLOW,
OPT_INDEX_ON,
OPT_INDEX_OFF,
OPT_UUID_ON,
@@ -446,7 +471,10 @@ static const match_table_t ovl_tokens = {
{OPT_UPPERDIR, "upperdir=%s"},
{OPT_WORKDIR, "workdir=%s"},
{OPT_DEFAULT_PERMISSIONS, "default_permissions"},
- {OPT_REDIRECT_DIR, "redirect_dir=%s"},
+ {OPT_REDIRECT_DIR_ON, "redirect_dir=on"},
+ {OPT_REDIRECT_DIR_OFF, "redirect_dir=off"},
+ {OPT_REDIRECT_DIR_FOLLOW, "redirect_dir=follow"},
+ {OPT_REDIRECT_DIR_NOFOLLOW, "redirect_dir=nofollow"},
{OPT_INDEX_ON, "index=on"},
{OPT_INDEX_OFF, "index=off"},
{OPT_USERXATTR, "userxattr"},
@@ -486,40 +514,12 @@ 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("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;
- int err;
bool metacopy_opt = false, redirect_opt = false;
bool nfs_export_opt = false, index_opt = false;
- 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];
@@ -554,11 +554,25 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
config->default_permissions = true;
break;
- case OPT_REDIRECT_DIR:
- kfree(config->redirect_mode);
- config->redirect_mode = match_strdup(&args[0]);
- if (!config->redirect_mode)
- return -ENOMEM;
+ case OPT_REDIRECT_DIR_ON:
+ config->redirect_mode = OVL_REDIRECT_ON;
+ redirect_opt = true;
+ break;
+
+ case OPT_REDIRECT_DIR_OFF:
+ config->redirect_mode = ovl_redirect_always_follow ?
+ OVL_REDIRECT_FOLLOW :
+ OVL_REDIRECT_NOFOLLOW;
+ redirect_opt = true;
+ break;
+
+ case OPT_REDIRECT_DIR_FOLLOW:
+ config->redirect_mode = OVL_REDIRECT_FOLLOW;
+ redirect_opt = true;
+ break;
+
+ case OPT_REDIRECT_DIR_NOFOLLOW:
+ config->redirect_mode = OVL_REDIRECT_NOFOLLOW;
redirect_opt = true;
break;
@@ -647,22 +661,18 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
config->ovl_volatile = false;
}
- err = ovl_parse_redirect_mode(config, config->redirect_mode);
- if (err)
- return err;
-
/*
* This is to make the logic below simpler. It doesn't make any other
- * difference, since config->redirect_dir is only used for upper.
+ * difference, since redirect_dir=on is only used for upper.
*/
- if (!config->upperdir && config->redirect_follow)
- config->redirect_dir = true;
+ if (!config->upperdir && config->redirect_mode == OVL_REDIRECT_FOLLOW)
+ config->redirect_mode = OVL_REDIRECT_ON;
/* Resolve metacopy -> redirect_dir dependency */
- if (config->metacopy && !config->redirect_dir) {
+ if (config->metacopy && !config->redirect_mode != OVL_REDIRECT_ON) {
if (metacopy_opt && redirect_opt) {
pr_err("conflicting options: metacopy=on,redirect_dir=%s\n",
- config->redirect_mode);
+ ovl_redirect_mode(config));
return -EINVAL;
}
if (redirect_opt) {
@@ -671,17 +681,18 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
* in this conflict.
*/
pr_info("disabling metacopy due to redirect_dir=%s\n",
- config->redirect_mode);
+ ovl_redirect_mode(config));
config->metacopy = false;
} else {
/* Automatically enable redirect otherwise. */
- config->redirect_follow = config->redirect_dir = true;
+ config->redirect_mode = OVL_REDIRECT_ON;
}
}
/* Resolve nfs_export -> index dependency */
if (config->nfs_export && !config->index) {
- if (!config->upperdir && config->redirect_follow) {
+ if (!config->upperdir &&
+ config->redirect_mode != OVL_REDIRECT_NOFOLLOW) {
pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n");
config->nfs_export = false;
} else if (nfs_export_opt && index_opt) {
@@ -726,9 +737,10 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
/* Resolve userxattr -> !redirect && !metacopy dependency */
if (config->userxattr) {
- if (config->redirect_follow && redirect_opt) {
+ if (redirect_opt &&
+ config->redirect_mode != OVL_REDIRECT_NOFOLLOW) {
pr_err("conflicting options: userxattr,redirect_dir=%s\n",
- config->redirect_mode);
+ ovl_redirect_mode(config));
return -EINVAL;
}
if (config->metacopy && metacopy_opt) {
@@ -741,7 +753,7 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
* options must be explicitly enabled if used together with
* userxattr.
*/
- config->redirect_dir = config->redirect_follow = false;
+ config->redirect_mode = OVL_REDIRECT_NOFOLLOW;
config->metacopy = false;
}
@@ -1325,10 +1337,17 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
if (err) {
pr_warn("failed to set xattr on upper\n");
ofs->noxattr = true;
- if (ofs->config.index || ofs->config.metacopy) {
- ofs->config.index = false;
+ if (ovl_redirect_follow(ofs)) {
+ ofs->config.redirect_mode = OVL_REDIRECT_NOFOLLOW;
+ pr_warn("...falling back to redirect_dir=nofollow.\n");
+ }
+ if (ofs->config.metacopy) {
ofs->config.metacopy = false;
- pr_warn("...falling back to index=off,metacopy=off.\n");
+ pr_warn("...falling back to metacopy=off.\n");
+ }
+ if (ofs->config.index) {
+ ofs->config.index = false;
+ pr_warn("...falling back to index=off.\n");
}
/*
* xattr support is required for persistent st_ino.
@@ -1566,7 +1585,7 @@ static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path)
pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n",
uuid_is_null(&sb->s_uuid) ? "null" :
"conflicting",
- path->dentry, ovl_xino_str[ofs->config.xino]);
+ path->dentry, ovl_xino_mode(&ofs->config));
}
}
@@ -1957,6 +1976,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
/* Is there a reason anyone would want not to share whiteouts? */
ofs->share_whiteout = true;
+ ofs->config.redirect_mode = ovl_redirect_mode_def();
ofs->config.index = ovl_index_def;
ofs->config.uuid = true;
ofs->config.nfs_export = ovl_nfs_export_def;
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 939e4d586ec2..7ef9e13c404a 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -506,13 +506,6 @@ bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags)
return !ovl_has_upperdata(d_inode(dentry));
}
-bool ovl_redirect_dir(struct super_block *sb)
-{
- struct ovl_fs *ofs = sb->s_fs_info;
-
- return ofs->config.redirect_dir && !ofs->noxattr;
-}
-
const char *ovl_dentry_get_redirect(struct dentry *dentry)
{
return OVL_I(d_inode(dentry))->redirect;
--
2.34.1
