Merge tag 'ovl-update-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs update from Miklos Szeredi:

 - Try to preserve holes in sparse files when copying up, thus saving
   disk space and improving performance.

 - Fix a performance regression introduced in v4.19 by preserving
   asynchronicity of IO when fowarding to underlying layers. Add VFS
   helpers to submit async iocbs.

 - Fix a regression in lseek(2) introduced in v4.19 that breaks >2G
   seeks on 32bit kernels.

 - Fix a corner case where st_ino/st_dev was not preserved across copy
   up.

 - Miscellaneous fixes and cleanups.

* tag 'ovl-update-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: fix lseek overflow on 32bit
  ovl: add splice file read write helper
  ovl: implement async IO routines
  vfs: add vfs_iocb_iter_[read|write] helper functions
  ovl: layer is const
  ovl: fix corner case of non-constant st_dev;st_ino
  ovl: fix corner case of conflicting lower layer uuid
  ovl: generalize the lower_fs[] array
  ovl: simplify ovl_same_sb() helper
  ovl: generalize the lower_layers[] array
  ovl: improving copy-up efficiency for big sparse file
  ovl: use ovl_inode_lock in ovl_llseek()
  ovl: use pr_fmt auto generate prefix
  ovl: fix wrong WARN_ON() in ovl_cache_update_ino()

1 files changed, 15 insertions, 8 deletions

diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 28348c44ea5b..89015ea822e7 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -24,6 +24,8 @@ struct ovl_sb {
 	dev_t pseudo_dev;
 	/* Unusable (conflicting) uuid */
 	bool bad_uuid;
+	/* Used as a lower layer (but maybe also as upper) */
+	bool is_lower;
 };
 
 struct ovl_layer {
@@ -38,18 +40,18 @@ struct ovl_layer {
 };
 
 struct ovl_path {
-	struct ovl_layer *layer;
+	const struct ovl_layer *layer;
 	struct dentry *dentry;
 };
 
 /* private information held for overlayfs's superblock */
 struct ovl_fs {
 	struct vfsmount *upper_mnt;
-	unsigned int numlower;
-	/* Number of unique lower sb that differ from upper sb */
-	unsigned int numlowerfs;
-	struct ovl_layer *lower_layers;
-	struct ovl_sb *lower_fs;
+	unsigned int numlayer;
+	/* Number of unique fs among layers including upper fs */
+	unsigned int numfs;
+	const struct ovl_layer *layers;
+	struct ovl_sb *fs;
 	/* workbasedir is the path at workdir= mount option */
 	struct dentry *workbasedir;
 	/* workdir is the 'work' directory under workbasedir */
@@ -71,10 +73,15 @@ struct ovl_fs {
 	struct inode *workbasedir_trap;
 	struct inode *workdir_trap;
 	struct inode *indexdir_trap;
-	/* Inode numbers in all layers do not use the high xino_bits */
-	unsigned int xino_bits;
+	/* -1: disabled, 0: same fs, 1..32: number of unused ino bits */
+	int xino_mode;
 };
 
+static inline struct ovl_fs *OVL_FS(struct super_block *sb)
+{
+	return (struct ovl_fs *)sb->s_fs_info;
+}
+
 /* private information held for every overlayfs dentry */
 struct ovl_entry {
 	union {