1 files changed, 169 insertions, 92 deletions

diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 40ac9ce2465a..2b210640036c 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -170,7 +170,7 @@ static struct ovl_cache_entry *ovl_cache_entry_new(struct ovl_readdir_data *rdd,
 	return p;
 }
 
-static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd,
+static bool ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd,
 				  const char *name, int len, u64 ino,
 				  unsigned int d_type)
 {
@@ -179,22 +179,22 @@ static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd,
 	struct ovl_cache_entry *p;
 
 	if (ovl_cache_entry_find_link(name, len, &newp, &parent))
-		return 0;
+		return true;
 
 	p = ovl_cache_entry_new(rdd, name, len, ino, d_type);
 	if (p == NULL) {
 		rdd->err = -ENOMEM;
-		return -ENOMEM;
+		return false;
 	}
 
 	list_add_tail(&p->l_node, rdd->list);
 	rb_link_node(&p->node, parent, newp);
 	rb_insert_color(&p->node, rdd->root);
 
-	return 0;
+	return true;
 }
 
-static int ovl_fill_lowest(struct ovl_readdir_data *rdd,
+static bool ovl_fill_lowest(struct ovl_readdir_data *rdd,
 			   const char *name, int namelen,
 			   loff_t offset, u64 ino, unsigned int d_type)
 {
@@ -211,7 +211,7 @@ static int ovl_fill_lowest(struct ovl_readdir_data *rdd,
 			list_add_tail(&p->l_node, &rdd->middle);
 	}
 
-	return rdd->err;
+	return rdd->err == 0;
 }
 
 void ovl_cache_free(struct list_head *list)
@@ -250,7 +250,7 @@ static void ovl_cache_put(struct ovl_dir_file *od, struct dentry *dentry)
 	}
 }
 
-static int ovl_fill_merge(struct dir_context *ctx, const char *name,
+static bool ovl_fill_merge(struct dir_context *ctx, const char *name,
 			  int namelen, loff_t offset, u64 ino,
 			  unsigned int d_type)
 {
@@ -264,11 +264,11 @@ static int ovl_fill_merge(struct dir_context *ctx, const char *name,
 		return ovl_fill_lowest(rdd, name, namelen, offset, ino, d_type);
 }
 
-static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd)
+static int ovl_check_whiteouts(const struct path *path, struct ovl_readdir_data *rdd)
 {
 	int err;
 	struct ovl_cache_entry *p;
-	struct dentry *dentry;
+	struct dentry *dentry, *dir = path->dentry;
 	const struct cred *old_cred;
 
 	old_cred = ovl_override_creds(rdd->dentry->d_sb);
@@ -278,7 +278,7 @@ static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd)
 		while (rdd->first_maybe_whiteout) {
 			p = rdd->first_maybe_whiteout;
 			rdd->first_maybe_whiteout = p->next_maybe_whiteout;
-			dentry = lookup_one_len(p->name, dir, p->len);
+			dentry = lookup_one(mnt_user_ns(path->mnt), p->name, dir, p->len);
 			if (!IS_ERR(dentry)) {
 				p->is_whiteout = ovl_is_whiteout(dentry);
 				dput(dentry);
@@ -291,13 +291,13 @@ static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd)
 	return err;
 }
 
-static inline int ovl_dir_read(struct path *realpath,
+static inline int ovl_dir_read(const struct path *realpath,
 			       struct ovl_readdir_data *rdd)
 {
 	struct file *realfile;
 	int err;
 
-	realfile = ovl_path_open(realpath, O_RDONLY | O_DIRECTORY);
+	realfile = ovl_path_open(realpath, O_RDONLY | O_LARGEFILE);
 	if (IS_ERR(realfile))
 		return PTR_ERR(realfile);
 
@@ -312,25 +312,13 @@ static inline int ovl_dir_read(struct path *realpath,
 	} while (!err && rdd->count);
 
 	if (!err && rdd->first_maybe_whiteout && rdd->dentry)
-		err = ovl_check_whiteouts(realpath->dentry, rdd);
+		err = ovl_check_whiteouts(realpath, rdd);
 
 	fput(realfile);
 
 	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;
@@ -438,15 +426,23 @@ static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry)
 
 /* Map inode number to lower fs unique range */
 static u64 ovl_remap_lower_ino(u64 ino, int xinobits, int fsid,
-			       const char *name, int namelen)
+			       const char *name, int namelen, bool warn)
 {
-	if (ino >> (64 - xinobits)) {
-		pr_warn_ratelimited("d_ino too big (%.*s, ino=%llu, xinobits=%d)\n",
-				    namelen, name, ino, xinobits);
+	unsigned int xinoshift = 64 - xinobits;
+
+	if (unlikely(ino >> xinoshift)) {
+		if (warn) {
+			pr_warn_ratelimited("d_ino too big (%.*s, ino=%llu, xinobits=%d)\n",
+					    namelen, name, ino, xinobits);
+		}
 		return ino;
 	}
 
-	return ino | ((u64)fsid) << (64 - xinobits);
+	/*
+	 * The lowest xinobit is reserved for mapping the non-peresistent inode
+	 * numbers range, but this range is only exposed via st_ino, not here.
+	 */
+	return ino | ((u64)fsid) << (xinoshift + 1);
 }
 
 /*
@@ -459,7 +455,7 @@ static u64 ovl_remap_lower_ino(u64 ino, int xinobits, int fsid,
  * copy up origin, call vfs_getattr() on the overlay entry to make
  * sure that d_ino will be consistent with st_ino from stat(2).
  */
-static int ovl_cache_update_ino(struct path *path, struct ovl_cache_entry *p)
+static int ovl_cache_update_ino(const struct path *path, struct ovl_cache_entry *p)
 
 {
 	struct dentry *dir = path->dentry;
@@ -483,8 +479,10 @@ static int ovl_cache_update_ino(struct path *path, struct ovl_cache_entry *p)
 			goto get;
 		}
 	}
-	this = lookup_one_len(p->name, dir, p->len);
+	this = lookup_one(mnt_user_ns(path->mnt), p->name, dir, p->len);
 	if (IS_ERR_OR_NULL(this) || !this->d_inode) {
+		/* Mark a stale entry */
+		p->is_whiteout = true;
 		if (IS_ERR(this)) {
 			err = PTR_ERR(this);
 			this = NULL;
@@ -515,7 +513,8 @@ get:
 	} else if (xinobits && !OVL_TYPE_UPPER(type)) {
 		ino = ovl_remap_lower_ino(ino, xinobits,
 					  ovl_layer_lower(this)->fsid,
-					  p->name, p->len);
+					  p->name, p->len,
+					  ovl_xino_warn(dir->d_sb));
 	}
 
 out:
@@ -529,7 +528,7 @@ fail:
 	goto out;
 }
 
-static int ovl_fill_plain(struct dir_context *ctx, const char *name,
+static bool ovl_fill_plain(struct dir_context *ctx, const char *name,
 			  int namelen, loff_t offset, u64 ino,
 			  unsigned int d_type)
 {
@@ -541,14 +540,14 @@ static int ovl_fill_plain(struct dir_context *ctx, const char *name,
 	p = ovl_cache_entry_new(rdd, name, namelen, ino, d_type);
 	if (p == NULL) {
 		rdd->err = -ENOMEM;
-		return -ENOMEM;
+		return false;
 	}
 	list_add_tail(&p->l_node, rdd->list);
 
-	return 0;
+	return true;
 }
 
-static int ovl_dir_read_impure(struct path *path,  struct list_head *list,
+static int ovl_dir_read_impure(const struct path *path,  struct list_head *list,
 			       struct rb_root *root)
 {
 	int err;
@@ -593,10 +592,11 @@ static int ovl_dir_read_impure(struct path *path,  struct list_head *list,
 	return 0;
 }
 
-static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path)
+static struct ovl_dir_cache *ovl_cache_get_impure(const struct path *path)
 {
 	int res;
 	struct dentry *dentry = path->dentry;
+	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
 	struct ovl_dir_cache *cache;
 
 	cache = ovl_dir_cache(d_inode(dentry));
@@ -623,8 +623,8 @@ static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path)
 		 * Removing the "impure" xattr is best effort.
 		 */
 		if (!ovl_want_write(dentry)) {
-			ovl_do_removexattr(ovl_dentry_upper(dentry),
-					   OVL_XATTR_IMPURE);
+			ovl_removexattr(ofs, ovl_dentry_upper(dentry),
+					OVL_XATTR_IMPURE);
 			ovl_drop_write(dentry);
 		}
 		ovl_clear_flag(OVL_IMPURE, d_inode(dentry));
@@ -645,9 +645,10 @@ struct ovl_readdir_translate {
 	u64 parent_ino;
 	int fsid;
 	int xinobits;
+	bool xinowarn;
 };
 
-static int ovl_fill_real(struct dir_context *ctx, const char *name,
+static bool ovl_fill_real(struct dir_context *ctx, const char *name,
 			   int namelen, loff_t offset, u64 ino,
 			   unsigned int d_type)
 {
@@ -665,7 +666,7 @@ static int ovl_fill_real(struct dir_context *ctx, const char *name,
 			ino = p->ino;
 	} else if (rdt->xinobits) {
 		ino = ovl_remap_lower_ino(ino, rdt->xinobits, rdt->fsid,
-					  name, namelen);
+					  name, namelen, rdt->xinowarn);
 	}
 
 	return orig_ctx->actor(orig_ctx, name, namelen, offset, ino, d_type);
@@ -696,6 +697,7 @@ static int ovl_iterate_real(struct file *file, struct dir_context *ctx)
 		.ctx.actor = ovl_fill_real,
 		.orig_ctx = ctx,
 		.xinobits = ovl_xino_bits(dir->d_sb),
+		.xinowarn = ovl_xino_warn(dir->d_sb),
 	};
 
 	if (rdt.xinobits && lower_layer)
@@ -732,8 +734,10 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
 	struct ovl_dir_file *od = file->private_data;
 	struct dentry *dentry = file->f_path.dentry;
 	struct ovl_cache_entry *p;
+	const struct cred *old_cred;
 	int err;
 
+	old_cred = ovl_override_creds(dentry->d_sb);
 	if (!ctx->pos)
 		ovl_dir_reset(file);
 
@@ -747,17 +751,20 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
 		    (ovl_same_fs(dentry->d_sb) &&
 		     (ovl_is_impure_dir(file) ||
 		      OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent))))) {
-			return ovl_iterate_real(file, ctx);
+			err = ovl_iterate_real(file, ctx);
+		} else {
+			err = iterate_dir(od->realfile, ctx);
 		}
-		return iterate_dir(od->realfile, ctx);
+		goto out;
 	}
 
 	if (!od->cache) {
 		struct ovl_dir_cache *cache;
 
 		cache = ovl_cache_get(dentry);
+		err = PTR_ERR(cache);
 		if (IS_ERR(cache))
-			return PTR_ERR(cache);
+			goto out;
 
 		od->cache = cache;
 		ovl_seek_cursor(od, ctx->pos);
@@ -769,15 +776,21 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
 			if (!p->ino) {
 				err = ovl_cache_update_ino(&file->f_path, p);
 				if (err)
-					return err;
+					goto out;
 			}
+		}
+		/* ovl_cache_update_ino() sets is_whiteout on stale entry */
+		if (!p->is_whiteout) {
 			if (!dir_emit(ctx, p->name, p->len, p->ino, p->type))
 				break;
 		}
 		od->cursor = p->l_node.next;
 		ctx->pos++;
 	}
-	return 0;
+	err = 0;
+out:
+	revert_creds(old_cred);
+	return err;
 }
 
 static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin)
@@ -820,47 +833,77 @@ out_unlock:
 	return res;
 }
 
-static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
-			 int datasync)
+static struct file *ovl_dir_open_realfile(const struct file *file,
+					  const struct path *realpath)
 {
+	struct file *res;
+	const struct cred *old_cred;
+
+	old_cred = ovl_override_creds(file_inode(file)->i_sb);
+	res = ovl_path_open(realpath, O_RDONLY | (file->f_flags & O_LARGEFILE));
+	revert_creds(old_cred);
+
+	return res;
+}
+
+/*
+ * Like ovl_real_fdget(), returns upperfile if dir was copied up since open.
+ * Unlike ovl_real_fdget(), this caches upperfile in file->private_data.
+ *
+ * TODO: use same abstract type for file->private_data of dir and file so
+ * upperfile could also be cached for files as well.
+ */
+struct file *ovl_dir_real_file(const struct file *file, bool want_upper)
+{
+
 	struct ovl_dir_file *od = file->private_data;
 	struct dentry *dentry = file->f_path.dentry;
-	struct file *realfile = od->realfile;
+	struct file *old, *realfile = od->realfile;
 
-	/* Nothing to sync for lower */
 	if (!OVL_TYPE_UPPER(ovl_path_type(dentry)))
-		return 0;
+		return want_upper ? NULL : realfile;
 
 	/*
 	 * Need to check if we started out being a lower dir, but got copied up
 	 */
 	if (!od->is_upper) {
-		struct inode *inode = file_inode(file);
-
 		realfile = READ_ONCE(od->upperfile);
 		if (!realfile) {
 			struct path upperpath;
 
 			ovl_path_upper(dentry, &upperpath);
-			realfile = ovl_path_open(&upperpath, O_RDONLY);
-
-			inode_lock(inode);
-			if (!od->upperfile) {
-				if (IS_ERR(realfile)) {
-					inode_unlock(inode);
-					return PTR_ERR(realfile);
-				}
-				smp_store_release(&od->upperfile, realfile);
-			} else {
-				/* somebody has beaten us to it */
-				if (!IS_ERR(realfile))
-					fput(realfile);
-				realfile = od->upperfile;
+			realfile = ovl_dir_open_realfile(file, &upperpath);
+			if (IS_ERR(realfile))
+				return realfile;
+
+			old = cmpxchg_release(&od->upperfile, NULL, realfile);
+			if (old) {
+				fput(realfile);
+				realfile = old;
 			}
-			inode_unlock(inode);
 		}
 	}
 
+	return realfile;
+}
+
+static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
+			 int datasync)
+{
+	struct file *realfile;
+	int err;
+
+	err = ovl_sync_status(OVL_FS(file->f_path.dentry->d_sb));
+	if (err <= 0)
+		return err;
+
+	realfile = ovl_dir_real_file(file, true);
+	err = PTR_ERR_OR_ZERO(realfile);
+
+	/* Nothing to sync for lower */
+	if (!realfile || err)
+		return err;
+
 	return vfs_fsync_range(realfile, start, end, datasync);
 }
 
@@ -893,7 +936,7 @@ static int ovl_dir_open(struct inode *inode, struct file *file)
 		return -ENOMEM;
 
 	type = ovl_path_real(file->f_path.dentry, &realpath);
-	realfile = ovl_path_open(&realpath, file->f_flags);
+	realfile = ovl_dir_open_realfile(file, &realpath);
 	if (IS_ERR(realfile)) {
 		kfree(od);
 		return PTR_ERR(realfile);
@@ -958,7 +1001,8 @@ del_entry:
 	return err;
 }
 
-void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list)
+void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
+			   struct list_head *list)
 {
 	struct ovl_cache_entry *p;
 
@@ -969,7 +1013,7 @@ void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list)
 		if (WARN_ON(!p->is_whiteout || !p->is_upper))
 			continue;
 
-		dentry = lookup_one_len(p->name, upper, p->len);
+		dentry = ovl_lookup_upper(ofs, p->name, upper, p->len);
 		if (IS_ERR(dentry)) {
 			pr_err("lookup '%s/%.*s' failed (%i)\n",
 			       upper->d_name.name, p->len, p->name,
@@ -977,13 +1021,13 @@ void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list)
 			continue;
 		}
 		if (dentry->d_inode)
-			ovl_cleanup(upper->d_inode, dentry);
+			ovl_cleanup(ofs, upper->d_inode, dentry);
 		dput(dentry);
 	}
 	inode_unlock(upper->d_inode);
 }
 
-static int ovl_check_d_type(struct dir_context *ctx, const char *name,
+static bool ovl_check_d_type(struct dir_context *ctx, const char *name,
 			  int namelen, loff_t offset, u64 ino,
 			  unsigned int d_type)
 {
@@ -992,19 +1036,19 @@ static int ovl_check_d_type(struct dir_context *ctx, const char *name,
 
 	/* Even if d_type is not supported, DT_DIR is returned for . and .. */
 	if (!strncmp(name, ".", namelen) || !strncmp(name, "..", namelen))
-		return 0;
+		return true;
 
 	if (d_type != DT_UNKNOWN)
 		rdd->d_type_supported = true;
 
-	return 0;
+	return true;
 }
 
 /*
  * Returns 1 if d_type is supported, 0 not supported/unknown. Negative values
  * if error is encountered.
  */
-int ovl_check_d_type_supported(struct path *realpath)
+int ovl_check_d_type_supported(const struct path *realpath)
 {
 	int err;
 	struct ovl_readdir_data rdd = {
@@ -1019,7 +1063,10 @@ int ovl_check_d_type_supported(struct path *realpath)
 	return rdd.d_type_supported;
 }
 
-static void ovl_workdir_cleanup_recurse(struct path *path, int level)
+#define OVL_INCOMPATDIR_NAME "incompat"
+
+static int ovl_workdir_cleanup_recurse(struct ovl_fs *ofs, const struct path *path,
+				       int level)
 {
 	int err;
 	struct inode *dir = path->dentry->d_inode;
@@ -1033,6 +1080,19 @@ static void ovl_workdir_cleanup_recurse(struct path *path, int level)
 		.root = &root,
 		.is_lowest = false,
 	};
+	bool incompat = false;
+
+	/*
+	 * The "work/incompat" directory is treated specially - if it is not
+	 * empty, instead of printing a generic error and mounting read-only,
+	 * we will error about incompat features and fail the mount.
+	 *
+	 * When called from ovl_indexdir_cleanup(), path->dentry->d_name.name
+	 * starts with '#'.
+	 */
+	if (level == 2 &&
+	    !strcmp(path->dentry->d_name.name, OVL_INCOMPATDIR_NAME))
+		incompat = true;
 
 	err = ovl_dir_read(path, &rdd);
 	if (err)
@@ -1047,38 +1107,48 @@ static void ovl_workdir_cleanup_recurse(struct path *path, int level)
 				continue;
 			if (p->len == 2 && p->name[1] == '.')
 				continue;
+		} else if (incompat) {
+			pr_err("overlay with incompat feature '%s' cannot be mounted\n",
+				p->name);
+			err = -EINVAL;
+			break;
 		}
-		dentry = lookup_one_len(p->name, path->dentry, p->len);
+		dentry = ovl_lookup_upper(ofs, p->name, path->dentry, p->len);
 		if (IS_ERR(dentry))
 			continue;
 		if (dentry->d_inode)
-			ovl_workdir_cleanup(dir, path->mnt, dentry, level);
+			err = ovl_workdir_cleanup(ofs, dir, path->mnt, dentry, level);
 		dput(dentry);
+		if (err)
+			break;
 	}
 	inode_unlock(dir);
 out:
 	ovl_cache_free(&list);
+	return err;
 }
 
-void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
-			 struct dentry *dentry, int level)
+int ovl_workdir_cleanup(struct ovl_fs *ofs, struct inode *dir,
+			struct vfsmount *mnt, struct dentry *dentry, int level)
 {
 	int err;
 
 	if (!d_is_dir(dentry) || level > 1) {
-		ovl_cleanup(dir, dentry);
-		return;
+		return ovl_cleanup(ofs, dir, dentry);
 	}
 
-	err = ovl_do_rmdir(dir, dentry);
+	err = ovl_do_rmdir(ofs, dir, dentry);
 	if (err) {
 		struct path path = { .mnt = mnt, .dentry = dentry };
 
 		inode_unlock(dir);
-		ovl_workdir_cleanup_recurse(&path, level + 1);
+		err = ovl_workdir_cleanup_recurse(ofs, &path, level + 1);
 		inode_lock_nested(dir, I_MUTEX_PARENT);
-		ovl_cleanup(dir, dentry);
+		if (!err)
+			err = ovl_cleanup(ofs, dir, dentry);
 	}
+
+	return err;
 }
 
 int ovl_indexdir_cleanup(struct ovl_fs *ofs)
@@ -1087,7 +1157,7 @@ int ovl_indexdir_cleanup(struct ovl_fs *ofs)
 	struct dentry *indexdir = ofs->indexdir;
 	struct dentry *index = NULL;
 	struct inode *dir = indexdir->d_inode;
-	struct path path = { .mnt = ofs->upper_mnt, .dentry = indexdir };
+	struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = indexdir };
 	LIST_HEAD(list);
 	struct rb_root root = RB_ROOT;
 	struct ovl_cache_entry *p;
@@ -1111,18 +1181,25 @@ int ovl_indexdir_cleanup(struct ovl_fs *ofs)
 			if (p->len == 2 && p->name[1] == '.')
 				continue;
 		}
-		index = lookup_one_len(p->name, indexdir, p->len);
+		index = ovl_lookup_upper(ofs, p->name, indexdir, p->len);
 		if (IS_ERR(index)) {
 			err = PTR_ERR(index);
 			index = NULL;
 			break;
 		}
+		/* Cleanup leftover from index create/cleanup attempt */
+		if (index->d_name.name[0] == '#') {
+			err = ovl_workdir_cleanup(ofs, dir, path.mnt, index, 1);
+			if (err)
+				break;
+			goto next;
+		}
 		err = ovl_verify_index(ofs, index);
 		if (!err) {
 			goto next;
 		} else if (err == -ESTALE) {
 			/* Cleanup stale index entries */
-			err = ovl_cleanup(dir, index);
+			err = ovl_cleanup(ofs, dir, index);
 		} else if (err != -ENOENT) {
 			/*
 			 * Abort mount to avoid corrupting the index if
@@ -1135,10 +1212,10 @@ int ovl_indexdir_cleanup(struct ovl_fs *ofs)
 			 * Whiteout orphan index to block future open by
 			 * handle after overlay nlink dropped to zero.
 			 */
-			err = ovl_cleanup_and_whiteout(indexdir, dir, index);
+			err = ovl_cleanup_and_whiteout(ofs, dir, index);
 		} else {
 			/* Cleanup orphan index entries */
-			err = ovl_cleanup(dir, index);
+			err = ovl_cleanup(ofs, dir, index);
 		}
 
 		if (err)