Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs updates from Miklos Szeredi:

 - Report constant st_ino values across copy-up even if underlying
   layers are on different filesystems, but using different st_dev
   values for each layer.

   Ideally we'd report the same st_dev across the overlay, and it's
   possible to do for filesystems that use only 32bits for st_ino by
   unifying the inum space. It would be nice if it wasn't a choice of 32
   or 64, rather filesystems could report their current maximum (that
   could change on resize, so it wouldn't be set in stone).

 - miscellaneus fixes and a cleanup of ovl_fill_super(), that was long
   overdue.

 - created a path_put_init() helper that clears out the pointers after
   putting the ref.

   I think this could be useful elsewhere, so added it to <linux/path.h>

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (30 commits)
  ovl: remove unneeded arg from ovl_verify_origin()
  ovl: Put upperdentry if ovl_check_origin() fails
  ovl: rename ufs to ofs
  ovl: clean up getting lower layers
  ovl: clean up workdir creation
  ovl: clean up getting upper layer
  ovl: move ovl_get_workdir() and ovl_get_lower_layers()
  ovl: reduce the number of arguments for ovl_workdir_create()
  ovl: change order of setup in ovl_fill_super()
  ovl: factor out ovl_free_fs() helper
  ovl: grab reference to workbasedir early
  ovl: split out ovl_get_indexdir() from ovl_fill_super()
  ovl: split out ovl_get_lower_layers() from ovl_fill_super()
  ovl: split out ovl_get_workdir() from ovl_fill_super()
  ovl: split out ovl_get_upper() from ovl_fill_super()
  ovl: split out ovl_get_lowerstack() from ovl_fill_super()
  ovl: split out ovl_get_workpath() from ovl_fill_super()
  ovl: split out ovl_get_upperpath() from ovl_fill_super()
  ovl: use path_put_init() in error paths for ovl_fill_super()
  vfs: add path_put_init()
  ...

1 files changed, 42 insertions, 13 deletions

diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index c310e3ff7f3f..0daa4354fec4 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -26,6 +26,7 @@ struct ovl_cache_entry {
 	struct list_head l_node;
 	struct rb_node node;
 	struct ovl_cache_entry *next_maybe_whiteout;
+	bool is_upper;
 	bool is_whiteout;
 	char name[];
 };
@@ -158,6 +159,7 @@ static struct ovl_cache_entry *ovl_cache_entry_new(struct ovl_readdir_data *rdd,
 	/* Defer setting d_ino for upper entry to ovl_iterate() */
 	if (ovl_calc_d_ino(rdd, p))
 		p->ino = 0;
+	p->is_upper = rdd->is_upper;
 	p->is_whiteout = false;
 
 	if (d_type == DT_CHR) {
@@ -316,21 +318,37 @@ static inline int ovl_dir_read(struct path *realpath,
 	return err;
 }
 
+/*
+ * Can we iterate real dir directly?
+ *
+ * Non-merge dir may contain whiteouts from a time it was a merge upper, before
+ * lower dir was removed under it and possibly before it was rotated from upper
+ * to lower layer.
+ */
+static bool ovl_dir_is_real(struct dentry *dir)
+{
+	return !ovl_test_flag(OVL_WHITEOUTS, d_inode(dir));
+}
+
 static void ovl_dir_reset(struct file *file)
 {
 	struct ovl_dir_file *od = file->private_data;
 	struct ovl_dir_cache *cache = od->cache;
 	struct dentry *dentry = file->f_path.dentry;
-	enum ovl_path_type type = ovl_path_type(dentry);
+	bool is_real;
 
 	if (cache && ovl_dentry_version_get(dentry) != cache->version) {
 		ovl_cache_put(od, dentry);
 		od->cache = NULL;
 		od->cursor = NULL;
 	}
-	WARN_ON(!od->is_real && !OVL_TYPE_MERGE(type));
-	if (od->is_real && OVL_TYPE_MERGE(type))
+	is_real = ovl_dir_is_real(dentry);
+	if (od->is_real != is_real) {
+		/* is_real can only become false when dir is copied up */
+		if (WARN_ON(is_real))
+			return;
 		od->is_real = false;
+	}
 }
 
 static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list,
@@ -816,7 +834,7 @@ static int ovl_dir_open(struct inode *inode, struct file *file)
 		return PTR_ERR(realfile);
 	}
 	od->realfile = realfile;
-	od->is_real = !OVL_TYPE_MERGE(type);
+	od->is_real = ovl_dir_is_real(file->f_path.dentry);
 	od->is_upper = OVL_TYPE_UPPER(type);
 	file->private_data = od;
 
@@ -835,7 +853,7 @@ const struct file_operations ovl_dir_operations = {
 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list)
 {
 	int err;
-	struct ovl_cache_entry *p;
+	struct ovl_cache_entry *p, *n;
 	struct rb_root root = RB_ROOT;
 
 	err = ovl_dir_read_merged(dentry, list, &root);
@@ -844,18 +862,29 @@ int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list)
 
 	err = 0;
 
-	list_for_each_entry(p, list, l_node) {
-		if (p->is_whiteout)
-			continue;
+	list_for_each_entry_safe(p, n, list, l_node) {
+		/*
+		 * Select whiteouts in upperdir, they should
+		 * be cleared when deleting this directory.
+		 */
+		if (p->is_whiteout) {
+			if (p->is_upper)
+				continue;
+			goto del_entry;
+		}
 
 		if (p->name[0] == '.') {
 			if (p->len == 1)
-				continue;
+				goto del_entry;
 			if (p->len == 2 && p->name[1] == '.')
-				continue;
+				goto del_entry;
 		}
 		err = -ENOTEMPTY;
 		break;
+
+del_entry:
+		list_del(&p->l_node);
+		kfree(p);
 	}
 
 	return err;
@@ -869,7 +898,7 @@ void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list)
 	list_for_each_entry(p, list, l_node) {
 		struct dentry *dentry;
 
-		if (!p->is_whiteout)
+		if (WARN_ON(!p->is_whiteout || !p->is_upper))
 			continue;
 
 		dentry = lookup_one_len(p->name, upper, p->len);
@@ -985,7 +1014,7 @@ void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
 }
 
 int ovl_indexdir_cleanup(struct dentry *dentry, struct vfsmount *mnt,
-			 struct path *lowerstack, unsigned int numlower)
+			 struct ovl_path *lower, unsigned int numlower)
 {
 	int err;
 	struct dentry *index = NULL;
@@ -1020,7 +1049,7 @@ int ovl_indexdir_cleanup(struct dentry *dentry, struct vfsmount *mnt,
 			index = NULL;
 			break;
 		}
-		err = ovl_verify_index(index, lowerstack, numlower);
+		err = ovl_verify_index(index, lower, numlower);
 		/* Cleanup stale and orphan index entries */
 		if (err && (err == -ESTALE || err == -ENOENT))
 			err = ovl_cleanup(dir, index);