Merge tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs updates from Miklos Szeredi:
 "This contains two new features:

   - Stack file operations: this allows removal of several hacks from
     the VFS, proper interaction of read-only open files with copy-up,
     possibility to implement fs modifying ioctls properly, and others.

   - Metadata only copy-up: when file is on lower layer and only
     metadata is modified (except size) then only copy up the metadata
     and continue to use the data from the lower file"

* tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (66 commits)
  ovl: Enable metadata only feature
  ovl: Do not do metacopy only for ioctl modifying file attr
  ovl: Do not do metadata only copy-up for truncate operation
  ovl: add helper to force data copy-up
  ovl: Check redirect on index as well
  ovl: Set redirect on upper inode when it is linked
  ovl: Set redirect on metacopy files upon rename
  ovl: Do not set dentry type ORIGIN for broken hardlinks
  ovl: Add an inode flag OVL_CONST_INO
  ovl: Treat metacopy dentries as type OVL_PATH_MERGE
  ovl: Check redirects for metacopy files
  ovl: Move some dir related ovl_lookup_single() code in else block
  ovl: Do not expose metacopy only dentry from d_real()
  ovl: Open file with data except for the case of fsync
  ovl: Add helper ovl_inode_realdata()
  ovl: Store lower data inode in ovl_inode
  ovl: Fix ovl_getattr() to get number of blocks from lower
  ovl: Add helper ovl_dentry_lowerdata() to get lower data dentry
  ovl: Copy up meta inode data from lowest data inode
  ovl: Modify ovl_lookup() and friends to lookup metacopy dentry
  ...

1 files changed, 43 insertions, 4 deletions

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 7538b9b56237..f61839e1054c 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -9,6 +9,7 @@
 
 #include <linux/kernel.h>
 #include <linux/uuid.h>
+#include <linux/fs.h>
 #include "ovl_entry.h"
 
 enum ovl_path_type {
@@ -28,6 +29,7 @@ enum ovl_path_type {
 #define OVL_XATTR_IMPURE OVL_XATTR_PREFIX "impure"
 #define OVL_XATTR_NLINK OVL_XATTR_PREFIX "nlink"
 #define OVL_XATTR_UPPER OVL_XATTR_PREFIX "upper"
+#define OVL_XATTR_METACOPY OVL_XATTR_PREFIX "metacopy"
 
 enum ovl_inode_flag {
         /* Pure upper dir that may contain non pure upper entries */
@@ -35,6 +37,9 @@ enum ovl_inode_flag {
         /* Non-merge dir that may contain whiteout entries */
         OVL_WHITEOUTS,
         OVL_INDEX,
+        OVL_UPPERDATA,
+        /* Inode number will remain constant over copy up. */
+        OVL_CONST_INO,
 };
 
 enum ovl_entry_flag {
@@ -190,6 +195,14 @@ static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
         return ret;
 }
 
+static inline bool ovl_open_flags_need_copy_up(int flags)
+{
+        if (!flags)
+                return false;
+
+        return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
+}
+
 /* util.c */
 int ovl_want_write(struct dentry *dentry);
 void ovl_drop_write(struct dentry *dentry);
@@ -206,15 +219,19 @@ 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);
 enum ovl_path_type ovl_path_real(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);
 struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
 struct dentry *ovl_dentry_real(struct dentry *dentry);
 struct dentry *ovl_i_dentry_upper(struct inode *inode);
 struct inode *ovl_inode_upper(struct inode *inode);
 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);
 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);
@@ -225,18 +242,23 @@ bool ovl_dentry_is_whiteout(struct dentry *dentry);
 void ovl_dentry_set_opaque(struct dentry *dentry);
 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
 void ovl_dentry_set_upper_alias(struct dentry *dentry);
+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_init(struct inode *inode, struct dentry *upperdentry,
-                    struct dentry *lowerdentry);
+                    struct dentry *lowerdentry, struct dentry *lowerdata);
 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
-void ovl_dentry_version_inc(struct dentry *dentry, bool impurity);
+void ovl_dir_modified(struct dentry *dentry, bool impurity);
 u64 ovl_dentry_version_get(struct dentry *dentry);
 bool ovl_is_whiteout(struct dentry *dentry);
 struct file *ovl_path_open(struct path *path, int flags);
-int ovl_copy_up_start(struct dentry *dentry);
+int ovl_copy_up_start(struct dentry *dentry, int flags);
 void ovl_copy_up_end(struct dentry *dentry);
+bool ovl_already_copied_up(struct dentry *dentry, int flags);
 bool ovl_check_origin_xattr(struct dentry *dentry);
 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
@@ -252,6 +274,9 @@ bool ovl_need_index(struct dentry *dentry);
 int ovl_nlink_start(struct dentry *dentry, bool *locked);
 void ovl_nlink_end(struct dentry *dentry, bool locked);
 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
+int ovl_check_metacopy_xattr(struct dentry *dentry);
+bool ovl_is_metacopy_dentry(struct dentry *dentry);
+char *ovl_get_redirect_xattr(struct dentry *dentry, int padding);
 
 static inline bool ovl_is_impuredir(struct dentry *dentry)
 {
@@ -324,7 +349,6 @@ int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
                   void *value, size_t size);
 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
-int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
 bool ovl_is_private_xattr(const char *name);
 
@@ -334,6 +358,8 @@ struct ovl_inode_params {
         struct ovl_path *lowerpath;
         struct dentry *index;
         unsigned int numlower;
+        char *redirect;
+        struct dentry *lowerdata;
 };
 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
@@ -348,6 +374,14 @@ static inline void ovl_copyattr(struct inode *from, struct inode *to)
         to->i_atime = from->i_atime;
         to->i_mtime = from->i_mtime;
         to->i_ctime = from->i_ctime;
+        i_size_write(to, i_size_read(from));
+}
+
+static inline void ovl_copyflags(struct inode *from, struct inode *to)
+{
+        unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME;
+
+        inode_set_flags(to, from->i_flags & mask, mask);
 }
 
 /* dir.c */
@@ -368,9 +402,14 @@ struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);
 
+/* file.c */
+extern const struct file_operations ovl_file_operations;
+
 /* copy_up.c */
 int ovl_copy_up(struct dentry *dentry);
+int ovl_copy_up_with_data(struct dentry *dentry);
 int ovl_copy_up_flags(struct dentry *dentry, int flags);
+int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
 int ovl_copy_xattr(struct dentry *old, struct dentry *new);
 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
 struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);