ovl: store enum redirect_mode in config instead of a string

Do all the logic to set the mode during mount options parsing and
do not keep the option string around.

Use a constant_table to translate from enum redirect mode to string
in preperation for new mount api option parsing.

The mount option "off" is translated to either "follow" or "nofollow",
depending on the "redirect_always_follow" build/module config, so
in effect, there are only three possible redirect modes.

This results in a minor change to the string that is displayed
in show_options() - when redirect_dir is enabled by default 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 "redirect_always_follow" build/module config.

The displayed mode reflects the effective mode, so mounting overlayfs
again with the dispalyed redirect_dir option will result with the same
effective and displayed mode.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>

1 files changed, 27 insertions, 12 deletions

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 05e9acfe1590..80c10228bd64 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -58,6 +58,13 @@ enum ovl_entry_flag {
 };
 
 enum {
+	OVL_REDIRECT_OFF,	/* "off" mode is never used. In effect	*/
+	OVL_REDIRECT_FOLLOW,	/* ...it translates to either "follow"	*/
+	OVL_REDIRECT_NOFOLLOW,	/* ...or "nofollow".			*/
+	OVL_REDIRECT_ON,
+};
+
+enum {
 	OVL_XINO_OFF,
 	OVL_XINO_AUTO,
 	OVL_XINO_ON,
@@ -352,17 +359,6 @@ static inline bool ovl_open_flags_need_copy_up(int flags)
 	return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
 }
 
-static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
-{
-	/*
-	 * To avoid regressions in existing setups with overlay lower offline
-	 * changes, we allow lower changes only if none of the new features
-	 * are used.
-	 */
-	return (!ofs->config.index && !ofs->config.metacopy &&
-		!ofs->config.redirect_dir && ofs->config.xino != OVL_XINO_ON);
-}
-
 
 /* util.c */
 int ovl_want_write(struct dentry *dentry);
@@ -421,7 +417,6 @@ 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);
@@ -489,6 +484,16 @@ static inline bool ovl_is_impuredir(struct super_block *sb,
 	return ovl_path_check_dir_xattr(ofs, &upperpath, OVL_XATTR_IMPURE);
 }
 
+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;
+}
+
 /*
  * With xino=auto, we do best effort to keep all inodes on same st_dev and
  * d_ino consistent with st_ino.
@@ -499,6 +504,16 @@ static inline bool ovl_xino_warn(struct ovl_fs *ofs)
 	return ofs->config.xino == OVL_XINO_ON;
 }
 
+/*
+ * To avoid regressions in existing setups with overlay lower offline changes,
+ * we allow lower changes only if none of the new features are used.
+ */
+static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
+{
+	return (!ofs->config.index && !ofs->config.metacopy &&
+		!ovl_redirect_dir(ofs) && !ovl_xino_warn(ofs));
+}
+
 /* All layers on same fs? */
 static inline bool ovl_same_fs(struct ovl_fs *ofs)
 {