1 files changed, 88 insertions, 95 deletions

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index cc8977498c48..a0967bb25003 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -32,15 +32,24 @@ static struct dentry *ovl_d_real(struct dentry *dentry,
 				 const struct inode *inode)
 {
 	struct dentry *real = NULL, *lower;
+	int err;
 
-	/* It's an overlay file */
+	/*
+	 * vfs is only expected to call d_real() with NULL from d_real_inode()
+	 * and with overlay inode from file_dentry() on an overlay file.
+	 *
+	 * TODO: remove @inode argument from d_real() API, remove code in this
+	 * function that deals with non-NULL @inode and remove d_real() call
+	 * from file_dentry().
+	 */
 	if (inode && d_inode(dentry) == inode)
 		return dentry;
+	else if (inode)
+		goto bug;
 
 	if (!d_is_reg(dentry)) {
-		if (!inode || inode == d_inode(dentry))
-			return dentry;
-		goto bug;
+		/* d_real_inode() is only relevant for regular files */
+		return dentry;
 	}
 
 	real = ovl_dentry_upper(dentry);
@@ -58,7 +67,9 @@ static struct dentry *ovl_d_real(struct dentry *dentry,
 	 * uprobes on offset within the file, so lowerdata should be available
 	 * when setting the uprobe.
 	 */
-	ovl_maybe_lookup_lowerdata(dentry);
+	err = ovl_verify_lowerdata(dentry);
+	if (err)
+		goto bug;
 	lower = ovl_dentry_lowerdata(dentry);
 	if (!lower)
 		goto bug;
@@ -101,8 +112,8 @@ static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak)
 static int ovl_dentry_revalidate_common(struct dentry *dentry,
 					unsigned int flags, bool weak)
 {
-	struct ovl_entry *oe = OVL_E(dentry);
-	struct ovl_path *lowerstack = ovl_lowerstack(oe);
+	struct ovl_entry *oe;
+	struct ovl_path *lowerstack;
 	struct inode *inode = d_inode_rcu(dentry);
 	struct dentry *upper;
 	unsigned int i;
@@ -112,6 +123,8 @@ static int ovl_dentry_revalidate_common(struct dentry *dentry,
 	if (!inode)
 		return -ECHILD;
 
+	oe = OVL_I_E(inode);
+	lowerstack = ovl_lowerstack(oe);
 	upper = ovl_i_dentry_upper(inode);
 	if (upper)
 		ret = ovl_revalidate_real(upper, flags, weak);
@@ -164,6 +177,7 @@ static void ovl_free_inode(struct inode *inode)
 	struct ovl_inode *oi = OVL_I(inode);
 
 	kfree(oi->redirect);
+	kfree(oi->oe);
 	mutex_destroy(&oi->lock);
 	kmem_cache_free(ovl_inode_cachep, oi);
 }
@@ -173,7 +187,7 @@ static void ovl_destroy_inode(struct inode *inode)
 	struct ovl_inode *oi = OVL_I(inode);
 
 	dput(oi->__upperdentry);
-	ovl_free_entry(oi->oe);
+	ovl_stack_put(ovl_lowerstack(oi->oe), ovl_numlower(oi->oe));
 	if (S_ISDIR(inode->i_mode))
 		ovl_dir_cache_free(inode);
 	else
@@ -182,7 +196,7 @@ static void ovl_destroy_inode(struct inode *inode)
 
 static void ovl_put_super(struct super_block *sb)
 {
-	struct ovl_fs *ofs = sb->s_fs_info;
+	struct ovl_fs *ofs = OVL_FS(sb);
 
 	if (ofs)
 		ovl_free_fs(ofs);
@@ -191,7 +205,7 @@ static void ovl_put_super(struct super_block *sb)
 /* Sync real dirty inodes in upper filesystem (if it exists) */
 static int ovl_sync_fs(struct super_block *sb, int wait)
 {
-	struct ovl_fs *ofs = sb->s_fs_info;
+	struct ovl_fs *ofs = OVL_FS(sb);
 	struct super_block *upper_sb;
 	int ret;
 
@@ -239,8 +253,9 @@ static int ovl_sync_fs(struct super_block *sb, int wait)
  */
 static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
-	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
-	struct dentry *root_dentry = dentry->d_sb->s_root;
+	struct super_block *sb = dentry->d_sb;
+	struct ovl_fs *ofs = OVL_FS(sb);
+	struct dentry *root_dentry = sb->s_root;
 	struct path path;
 	int err;
 
@@ -250,6 +265,8 @@ static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
 	if (!err) {
 		buf->f_namelen = ofs->namelen;
 		buf->f_type = OVERLAYFS_SUPER_MAGIC;
+		if (ovl_has_fsid(ofs))
+			buf->f_fsid = uuid_to_fsid(sb->s_uuid.b);
 	}
 
 	return err;
@@ -397,6 +414,7 @@ static int ovl_lower_dir(const char *name, struct path *path,
 		pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n",
 			name);
 	}
+	ofs->nofh |= !fh_type;
 	/*
 	 * Decoding origin file handle is required for persistent st_ino.
 	 * Without persistent st_ino, xino=auto falls back to xino=off.
@@ -427,68 +445,6 @@ static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir)
 	return ok;
 }
 
-static int ovl_own_xattr_get(const struct xattr_handler *handler,
-			     struct dentry *dentry, struct inode *inode,
-			     const char *name, void *buffer, size_t size)
-{
-	return -EOPNOTSUPP;
-}
-
-static int ovl_own_xattr_set(const struct xattr_handler *handler,
-			     struct mnt_idmap *idmap,
-			     struct dentry *dentry, struct inode *inode,
-			     const char *name, const void *value,
-			     size_t size, int flags)
-{
-	return -EOPNOTSUPP;
-}
-
-static int ovl_other_xattr_get(const struct xattr_handler *handler,
-			       struct dentry *dentry, struct inode *inode,
-			       const char *name, void *buffer, size_t size)
-{
-	return ovl_xattr_get(dentry, inode, name, buffer, size);
-}
-
-static int ovl_other_xattr_set(const struct xattr_handler *handler,
-			       struct mnt_idmap *idmap,
-			       struct dentry *dentry, struct inode *inode,
-			       const char *name, const void *value,
-			       size_t size, int flags)
-{
-	return ovl_xattr_set(dentry, inode, name, value, size, flags);
-}
-
-static const struct xattr_handler ovl_own_trusted_xattr_handler = {
-	.prefix	= OVL_XATTR_TRUSTED_PREFIX,
-	.get = ovl_own_xattr_get,
-	.set = ovl_own_xattr_set,
-};
-
-static const struct xattr_handler ovl_own_user_xattr_handler = {
-	.prefix	= OVL_XATTR_USER_PREFIX,
-	.get = ovl_own_xattr_get,
-	.set = ovl_own_xattr_set,
-};
-
-static const struct xattr_handler ovl_other_xattr_handler = {
-	.prefix	= "", /* catch all */
-	.get = ovl_other_xattr_get,
-	.set = ovl_other_xattr_set,
-};
-
-static const struct xattr_handler *ovl_trusted_xattr_handlers[] = {
-	&ovl_own_trusted_xattr_handler,
-	&ovl_other_xattr_handler,
-	NULL
-};
-
-static const struct xattr_handler *ovl_user_xattr_handlers[] = {
-	&ovl_own_user_xattr_handler,
-	&ovl_other_xattr_handler,
-	NULL
-};
-
 static int ovl_setup_trap(struct super_block *sb, struct dentry *dir,
 			  struct inode **ptrap, const char *name)
 {
@@ -562,11 +518,6 @@ static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs,
 	upper_layer->idx = 0;
 	upper_layer->fsid = 0;
 
-	err = -ENOMEM;
-	upper_layer->name = kstrdup(ofs->config.upperdir, GFP_KERNEL);
-	if (!upper_layer->name)
-		goto out;
-
 	/*
 	 * Inherit SB_NOSEC flag from upperdir.
 	 *
@@ -634,7 +585,7 @@ static int ovl_check_rename_whiteout(struct ovl_fs *ofs)
 	if (IS_ERR(whiteout))
 		goto cleanup_temp;
 
-	err = ovl_is_whiteout(whiteout);
+	err = ovl_upper_is_whiteout(ofs, whiteout);
 
 	/* Best effort cleanup of whiteout and temp file */
 	if (err)
@@ -770,6 +721,10 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 			ofs->config.index = false;
 			pr_warn("...falling back to index=off.\n");
 		}
+		if (ovl_has_fsid(ofs)) {
+			ofs->config.uuid = OVL_UUID_NULL;
+			pr_warn("...falling back to uuid=null.\n");
+		}
 		/*
 		 * xattr support is required for persistent st_ino.
 		 * Without persistent st_ino, xino=auto falls back to xino=off.
@@ -815,6 +770,7 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 		ofs->config.index = false;
 		pr_warn("upper fs does not support file handles, falling back to index=off.\n");
 	}
+	ofs->nofh |= !fh_type;
 
 	/* Check if upper fs has 32bit inode numbers */
 	if (fh_type != FILEID_INO32_GEN)
@@ -869,15 +825,20 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
 {
 	struct vfsmount *mnt = ovl_upper_mnt(ofs);
 	struct dentry *indexdir;
+	struct dentry *origin = ovl_lowerstack(oe)->dentry;
+	const struct ovl_fh *fh;
 	int err;
 
+	fh = ovl_get_origin_fh(ofs, origin);
+	if (IS_ERR(fh))
+		return PTR_ERR(fh);
+
 	err = mnt_want_write(mnt);
 	if (err)
-		return err;
+		goto out_free_fh;
 
 	/* Verify lower root is upper root origin */
-	err = ovl_verify_origin(ofs, upperpath->dentry,
-				ovl_lowerstack(oe)->dentry, true);
+	err = ovl_verify_origin_fh(ofs, upperpath->dentry, fh, true);
 	if (err) {
 		pr_err("failed to verify upper root origin\n");
 		goto out;
@@ -909,9 +870,10 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
 		 * directory entries.
 		 */
 		if (ovl_check_origin_xattr(ofs, ofs->indexdir)) {
-			err = ovl_verify_set_fh(ofs, ofs->indexdir,
-						OVL_XATTR_ORIGIN,
-						upperpath->dentry, true, false);
+			err = ovl_verify_origin_xattr(ofs, ofs->indexdir,
+						      OVL_XATTR_ORIGIN,
+						      upperpath->dentry, true,
+						      false);
 			if (err)
 				pr_err("failed to verify index dir 'origin' xattr\n");
 		}
@@ -929,6 +891,8 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
 
 out:
 	mnt_drop_write(mnt);
+out_free_fh:
+	kfree(fh);
 	return err;
 }
 
@@ -1110,7 +1074,8 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
 		layers[ofs->numlayer].idx = ofs->numlayer;
 		layers[ofs->numlayer].fsid = fsid;
 		layers[ofs->numlayer].fs = &ofs->fs[fsid];
-		layers[ofs->numlayer].name = l->name;
+		/* Store for printing lowerdir=... in ovl_show_options() */
+		ofs->config.lowerdirs[ofs->numlayer] = l->name;
 		l->name = NULL;
 		ofs->numlayer++;
 		ofs->fs[fsid].is_lower = true;
@@ -1355,8 +1320,19 @@ int ovl_fill_super(struct super_block *sb, struct fs_context *fc)
 	if (!layers)
 		goto out_err;
 
+	ofs->config.lowerdirs = kcalloc(ctx->nr + 1, sizeof(char *), GFP_KERNEL);
+	if (!ofs->config.lowerdirs) {
+		kfree(layers);
+		goto out_err;
+	}
 	ofs->layers = layers;
-	/* Layer 0 is reserved for upper even if there's no upper */
+	/*
+	 * Layer 0 is reserved for upper even if there's no upper.
+	 * config.lowerdirs[0] is used for storing the user provided colon
+	 * separated lowerdir string.
+	 */
+	ofs->config.lowerdirs[0] = ctx->lowerdir_all;
+	ctx->lowerdir_all = NULL;
 	ofs->numlayer = 1;
 
 	sb->s_stack_depth = 0;
@@ -1416,9 +1392,12 @@ int ovl_fill_super(struct super_block *sb, struct fs_context *fc)
 	if (!ovl_upper_mnt(ofs))
 		sb->s_flags |= SB_RDONLY;
 
-	if (!ofs->config.uuid && ofs->numfs > 1) {
-		pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=on.\n");
-		ofs->config.uuid = true;
+	if (!ovl_origin_uuid(ofs) && ofs->numfs > 1) {
+		pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=null.\n");
+		ofs->config.uuid = OVL_UUID_NULL;
+	} else if (ovl_has_fsid(ofs) && ovl_upper_mnt(ofs)) {
+		/* Use per instance persistent uuid/fsid */
+		ovl_init_uuid_xattr(sb, ofs, &ctx->upper);
 	}
 
 	if (!ovl_force_readonly(ofs) && ofs->config.index) {
@@ -1449,18 +1428,32 @@ int ovl_fill_super(struct super_block *sb, struct fs_context *fc)
 		ofs->config.nfs_export = false;
 	}
 
+	/*
+	 * Support encoding decodable file handles with nfs_export=on
+	 * and encoding non-decodable file handles with nfs_export=off
+	 * if all layers support file handles.
+	 */
 	if (ofs->config.nfs_export)
 		sb->s_export_op = &ovl_export_operations;
+	else if (!ofs->nofh)
+		sb->s_export_op = &ovl_export_fid_operations;
 
 	/* Never override disk quota limits or use reserved space */
 	cap_lower(cred->cap_effective, CAP_SYS_RESOURCE);
 
 	sb->s_magic = OVERLAYFS_SUPER_MAGIC;
-	sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers :
-		ovl_trusted_xattr_handlers;
+	sb->s_xattr = ovl_xattr_handlers(ofs);
 	sb->s_fs_info = ofs;
+#ifdef CONFIG_FS_POSIX_ACL
 	sb->s_flags |= SB_POSIXACL;
-	sb->s_iflags |= SB_I_SKIP_SYNC | SB_I_IMA_UNVERIFIABLE_SIGNATURE;
+#endif
+	sb->s_iflags |= SB_I_SKIP_SYNC;
+	/*
+	 * Ensure that umask handling is done by the filesystems used
+	 * for the the upper layer instead of overlayfs as that would
+	 * lead to unexpected results.
+	 */
+	sb->s_iflags |= SB_I_NOUMASK;
 
 	err = -ENOMEM;
 	root_dentry = ovl_get_root(sb, ctx->upper.dentry, oe);
@@ -1479,7 +1472,7 @@ out_err:
 	return err;
 }
 
-static struct file_system_type ovl_fs_type = {
+struct file_system_type ovl_fs_type = {
 	.owner			= THIS_MODULE,
 	.name			= "overlay",
 	.init_fs_context	= ovl_init_fs_context,