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, 4 insertions, 12 deletions

diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 85907d5b9c2c..4b2084d0f1fb 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -989,8 +989,7 @@ struct dentry_operations {
 	char *(*d_dname)(struct dentry *, char *, int);
 	struct vfsmount *(*d_automount)(struct path *);
 	int (*d_manage)(const struct path *, bool);
-	struct dentry *(*d_real)(struct dentry *, const struct inode *,
-				 unsigned int, unsigned int);
+	struct dentry *(*d_real)(struct dentry *, const struct inode *);
 };
 
   d_revalidate: called when the VFS needs to revalidate a dentry. This
@@ -1124,22 +1123,15 @@ struct dentry_operations {
 	dentry being transited from.
 
   d_real: overlay/union type filesystems implement this method to return one of
-	the underlying dentries hidden by the overlay.  It is used in three
+	the underlying dentries hidden by the overlay.  It is used in two
 	different modes:
 
-	Called from open it may need to copy-up the file depending on the
-	supplied open flags.  This mode is selected with a non-zero flags
-	argument.  In this mode the d_real method can return an error.
-
 	Called from file_dentry() it returns the real dentry matching the inode
 	argument.  The real dentry may be from a lower layer already copied up,
 	but still referenced from the file.  This mode is selected with a
-	non-NULL inode argument.  This will always succeed.
-
-	With NULL inode and zero flags the topmost real underlying dentry is
-	returned.  This will always succeed.
+	non-NULL inode argument.
 
-	This method is never called with both non-NULL inode and non-zero flags.
+	With NULL inode the topmost real underlying dentry is returned.
 
 Each dentry has a pointer to its parent dentry, as well as a hash list
 of child dentries. Child dentries are basically like files in a