Merge tag 'ovl-update-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs

Pull overlayfs update from Amir Goldstein:

 - fix two NULL pointer deref bugs (Zhihao Cheng)

 - add support for "data-only" lower layers destined to be used by
   composefs

 - port overlayfs to the new mount api (Christian Brauner)

* tag 'ovl-update-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs: (26 commits)
  ovl: add Amir as co-maintainer
  ovl: reserve ability to reconfigure mount options with new mount api
  ovl: modify layer parameter parsing
  ovl: port to new mount api
  ovl: factor out ovl_parse_options() helper
  ovl: store enum redirect_mode in config instead of a string
  ovl: pass ovl_fs to xino helpers
  ovl: clarify ovl_get_root() semantics
  ovl: negate the ofs->share_whiteout boolean
  ovl: check type and offset of struct vfsmount in ovl_entry
  ovl: implement lazy lookup of lowerdata in data-only layers
  ovl: prepare for lazy lookup of lowerdata inode
  ovl: prepare to store lowerdata redirect for lazy lowerdata lookup
  ovl: implement lookup in data-only layers
  ovl: introduce data-only lower layers
  ovl: remove unneeded goto instructions
  ovl: deduplicate lowerdata and lowerstack[]
  ovl: deduplicate lowerpath and lowerstack[]
  ovl: move ovl_entry into ovl_inode
  ovl: factor out ovl_free_entry() and ovl_stack_*() helpers
  ...

1 files changed, 81 insertions, 25 deletions

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 23686e8a06c4..4142d1a457ff 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -58,11 +58,26 @@ 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,
 };
 
+/* The set of options that user requested explicitly via mount options */
+struct ovl_opt_set {
+	bool metacopy;
+	bool redirect;
+	bool nfs_export;
+	bool index;
+};
+
 /*
  * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
  * where:
@@ -353,17 +368,29 @@ 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);
-}
 
+/* params.c */
+#define OVL_MAX_STACK 500
+
+struct ovl_fs_context_layer {
+	char *name;
+	struct path path;
+};
+
+struct ovl_fs_context {
+	struct path upper;
+	struct path work;
+	size_t capacity;
+	size_t nr; /* includes nr_data */
+	size_t nr_data;
+	struct ovl_opt_set set;
+	struct ovl_fs_context_layer *lower;
+};
+
+int ovl_parse_param_upperdir(const char *name, struct fs_context *fc,
+			     bool workdir);
+int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc);
+void ovl_parse_param_drop_lowerdir(struct ovl_fs_context *ctx);
 
 /* util.c */
 int ovl_want_write(struct dentry *dentry);
@@ -374,21 +401,30 @@ int ovl_can_decode_fh(struct super_block *sb);
 struct dentry *ovl_indexdir(struct super_block *sb);
 bool ovl_index_all(struct super_block *sb);
 bool ovl_verify_lower(struct super_block *sb);
+struct ovl_path *ovl_stack_alloc(unsigned int n);
+void ovl_stack_cpy(struct ovl_path *dst, struct ovl_path *src, unsigned int n);
+void ovl_stack_put(struct ovl_path *stack, unsigned int n);
+void ovl_stack_free(struct ovl_path *stack, unsigned int n);
 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
+void ovl_free_entry(struct ovl_entry *oe);
 bool ovl_dentry_remote(struct dentry *dentry);
-void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry,
-			     unsigned int mask);
+void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry);
+void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry,
+			   struct ovl_entry *oe);
+void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry,
+			   struct ovl_entry *oe, unsigned int mask);
 bool ovl_dentry_weird(struct dentry *dentry);
 enum ovl_path_type ovl_path_type(struct dentry *dentry);
 void ovl_path_upper(struct dentry *dentry, struct path *path);
 void ovl_path_lower(struct dentry *dentry, struct path *path);
 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
-void ovl_i_path_real(struct inode *inode, struct path *path);
+struct inode *ovl_i_path_real(struct inode *inode, struct path *path);
 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
 enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path);
 struct dentry *ovl_dentry_upper(struct dentry *dentry);
 struct dentry *ovl_dentry_lower(struct dentry *dentry);
 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
+int ovl_dentry_set_lowerdata(struct dentry *dentry, struct ovl_path *datapath);
 const struct ovl_layer *ovl_i_layer_lower(struct inode *inode);
 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
 struct dentry *ovl_dentry_real(struct dentry *dentry);
@@ -398,6 +434,7 @@ struct inode *ovl_inode_lower(struct inode *inode);
 struct inode *ovl_inode_lowerdata(struct inode *inode);
 struct inode *ovl_inode_real(struct inode *inode);
 struct inode *ovl_inode_realdata(struct inode *inode);
+const char *ovl_lowerdata_redirect(struct inode *inode);
 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
@@ -412,7 +449,6 @@ 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);
@@ -480,31 +516,51 @@ 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.
  * With xino=on, we do the same effort but we warn if we failed.
  */
-static inline bool ovl_xino_warn(struct super_block *sb)
+static inline bool ovl_xino_warn(struct ovl_fs *ofs)
 {
-	return OVL_FS(sb)->config.xino == OVL_XINO_ON;
+	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 super_block *sb)
+static inline bool ovl_same_fs(struct ovl_fs *ofs)
 {
-	return OVL_FS(sb)->xino_mode == 0;
+	return ofs->xino_mode == 0;
 }
 
 /* All overlay inodes have same st_dev? */
-static inline bool ovl_same_dev(struct super_block *sb)
+static inline bool ovl_same_dev(struct ovl_fs *ofs)
 {
-	return OVL_FS(sb)->xino_mode >= 0;
+	return ofs->xino_mode >= 0;
 }
 
-static inline unsigned int ovl_xino_bits(struct super_block *sb)
+static inline unsigned int ovl_xino_bits(struct ovl_fs *ofs)
 {
-	return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0;
+	return ovl_same_dev(ofs) ? ofs->xino_mode : 0;
 }
 
 static inline void ovl_inode_lock(struct inode *inode)
@@ -550,6 +606,7 @@ struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
 				struct dentry *origin, bool verify);
 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
+int ovl_maybe_lookup_lowerdata(struct dentry *dentry);
 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 			  unsigned int flags);
 bool ovl_lower_positive(struct dentry *dentry);
@@ -646,11 +703,10 @@ bool ovl_is_private_xattr(struct super_block *sb, const char *name);
 struct ovl_inode_params {
 	struct inode *newinode;
 	struct dentry *upperdentry;
-	struct ovl_path *lowerpath;
+	struct ovl_entry *oe;
 	bool index;
-	unsigned int numlower;
 	char *redirect;
-	struct dentry *lowerdata;
+	char *lowerdata_redirect;
 };
 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
 		    unsigned long ino, int fsid);