Merge tag 'pull-tmpfile' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs tmpfile updates from Al Viro:
 "Miklos' ->tmpfile() signature change; pass an unopened struct file to
  it, let it open the damn thing. Allows to add tmpfile support to FUSE"

* tag 'pull-tmpfile' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fuse: implement ->tmpfile()
  vfs: open inside ->tmpfile()
  vfs: move open right after ->tmpfile()
  vfs: make vfs_tmpfile() static
  ovl: use vfs_tmpfile_open() helper
  cachefiles: use vfs_tmpfile_open() helper
  cachefiles: only pass inode to *mark_inode_inuse() helpers
  cachefiles: tmpfile error handling cleanup
  hugetlbfs: cleanup mknod and tmpfile
  vfs: add vfs_tmpfile_open() helper

Author: torvalds

Documentation/filesystems/locking.rst

@@ -79,7 +79,8 @@ prototypes::
 	int (*atomic_open)(struct inode *, struct dentry *,
 				struct file *, unsigned open_flag,
 				umode_t create_mode);
-	int (*tmpfile) (struct inode *, struct dentry *, umode_t);
+	int (*tmpfile) (struct user_namespace *, struct inode *,
+			struct file *, umode_t);
 	int (*fileattr_set)(struct user_namespace *mnt_userns,
 			    struct dentry *dentry, struct fileattr *fa);
 	int (*fileattr_get)(struct dentry *dentry, struct fileattr *fa);

Documentation/filesystems/porting.rst

@@ -933,3 +933,13 @@ to) and true - "keep going" (as 0 in old calling conventions).  Rationale:
 callers never looked at specific -E... values anyway.  ->iterate() and
 ->iterate_shared() instance require no changes at all, all filldir_t ones in
 the tree converted.
+
+---
+
+**mandatory**
+
+Calling conventions for ->tmpfile() have changed.  It now takes a struct
+file pointer instead of struct dentry pointer.  d_tmpfile() is similarly
+changed to simplify callers.  The passed file is in a non-open state and on
+success must be opened before returning (e.g. by calling
+finish_open_simple()).

Documentation/filesystems/vfs.rst

@@ -442,7 +442,7 @@ As of kernel 2.6.22, the following members are defined:
 		void (*update_time)(struct inode *, struct timespec *, int);
 		int (*atomic_open)(struct inode *, struct dentry *, struct file *,
 				   unsigned open_flag, umode_t create_mode);
-		int (*tmpfile) (struct user_namespace *, struct inode *, struct dentry *, umode_t);
+		int (*tmpfile) (struct user_namespace *, struct inode *, struct file *, umode_t);
 	        int (*set_acl)(struct user_namespace *, struct inode *, struct posix_acl *, int);
 		int (*fileattr_set)(struct user_namespace *mnt_userns,
 				    struct dentry *dentry, struct fileattr *fa);
@@ -592,7 +592,9 @@ otherwise noted.
 ``tmpfile``
 	called in the end of O_TMPFILE open().  Optional, equivalent to
 	atomically creating, opening and unlinking a file in given
-	directory.
+	directory.  On success needs to return with the file already
+	open; this can be done by calling finish_open_simple() right at
+	the end.
 
 ``fileattr_get``
 	called on ioctl(FS_IOC_GETFLAGS) and ioctl(FS_IOC_FSGETXATTR) to

fs/bad_inode.c

@@ -147,7 +147,7 @@ static int bad_inode_atomic_open(struct inode *inode, struct dentry *dentry,
 }
 
 static int bad_inode_tmpfile(struct user_namespace *mnt_userns,
-			     struct inode *inode, struct dentry *dentry,
+			     struct inode *inode, struct file *file,
 			     umode_t mode)
 {
 	return -EIO;

fs/btrfs/inode.c

@@ -10018,15 +10018,15 @@ static int btrfs_permission(struct user_namespace *mnt_userns,
 }
 
 static int btrfs_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
-			 struct dentry *dentry, umode_t mode)
+			 struct file *file, umode_t mode)
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 	struct btrfs_trans_handle *trans;
 	struct btrfs_root *root = BTRFS_I(dir)->root;
 	struct inode *inode;
 	struct btrfs_new_inode_args new_inode_args = {
 		.dir = dir,
-		.dentry = dentry,
+		.dentry = file->f_path.dentry,
 		.orphan = true,
 	};
 	unsigned int trans_num_items;
@@ -10063,7 +10063,7 @@ static int btrfs_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
 	set_nlink(inode, 1);
 
 	if (!ret) {
-		d_tmpfile(dentry, inode);
+		d_tmpfile(file, inode);
 		unlock_new_inode(inode);
 		mark_inode_dirty(inode);
 	}
@@ -10075,7 +10075,7 @@ static int btrfs_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
 out_inode:
 	if (ret)
 		iput(inode);
-	return ret;
+	return finish_open_simple(file, ret);
 }
 
 void btrfs_set_range_writeback(struct btrfs_inode *inode, u64 start, u64 end)

fs/cachefiles/namei.c

@@ -15,9 +15,8 @@
  * file or directory.  The caller must hold the inode lock.
  */
 static bool __cachefiles_mark_inode_in_use(struct cachefiles_object *object,
-					   struct dentry *dentry)
+					   struct inode *inode)
 {
-	struct inode *inode = d_backing_inode(dentry);
 	bool can_use = false;
 
 	if (!(inode->i_flags & S_KERNEL_FILE)) {
@@ -26,21 +25,18 @@ static bool __cachefiles_mark_inode_in_use(struct cachefiles_object *object,
 		can_use = true;
 	} else {
 		trace_cachefiles_mark_failed(object, inode);
-		pr_notice("cachefiles: Inode already in use: %pd (B=%lx)\n",
-			  dentry, inode->i_ino);
 	}
 
 	return can_use;
 }
 
 static bool cachefiles_mark_inode_in_use(struct cachefiles_object *object,
-					 struct dentry *dentry)
+					 struct inode *inode)
 {
-	struct inode *inode = d_backing_inode(dentry);
 	bool can_use;
 
 	inode_lock(inode);
-	can_use = __cachefiles_mark_inode_in_use(object, dentry);
+	can_use = __cachefiles_mark_inode_in_use(object, inode);
 	inode_unlock(inode);
 	return can_use;
 }
@@ -49,21 +45,17 @@ static bool cachefiles_mark_inode_in_use(struct cachefiles_object *object,
  * Unmark a backing inode.  The caller must hold the inode lock.
  */
 static void __cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
-					     struct dentry *dentry)
+					     struct inode *inode)
 {
-	struct inode *inode = d_backing_inode(dentry);
-
 	inode->i_flags &= ~S_KERNEL_FILE;
 	trace_cachefiles_mark_inactive(object, inode);
 }
 
 static void cachefiles_do_unmark_inode_in_use(struct cachefiles_object *object,
-					      struct dentry *dentry)
+					      struct inode *inode)
 {
-	struct inode *inode = d_backing_inode(dentry);
-
 	inode_lock(inode);
-	__cachefiles_unmark_inode_in_use(object, dentry);
+	__cachefiles_unmark_inode_in_use(object, inode);
 	inode_unlock(inode);
 }
 
@@ -77,14 +69,12 @@ void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
 	struct cachefiles_cache *cache = object->volume->cache;
 	struct inode *inode = file_inode(file);
 
-	if (inode) {
-		cachefiles_do_unmark_inode_in_use(object, file->f_path.dentry);
+	cachefiles_do_unmark_inode_in_use(object, inode);
 
-		if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) {
-			atomic_long_add(inode->i_blocks, &cache->b_released);
-			if (atomic_inc_return(&cache->f_released))
-				cachefiles_state_changed(cache);
-		}
+	if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) {
+		atomic_long_add(inode->i_blocks, &cache->b_released);
+		if (atomic_inc_return(&cache->f_released))
+			cachefiles_state_changed(cache);
 	}
 }
 
@@ -164,8 +154,11 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 	inode_lock(d_inode(subdir));
 	inode_unlock(d_inode(dir));
 
-	if (!__cachefiles_mark_inode_in_use(NULL, subdir))
+	if (!__cachefiles_mark_inode_in_use(NULL, d_inode(subdir))) {
+		pr_notice("cachefiles: Inode already in use: %pd (B=%lx)\n",
+			  subdir, d_inode(subdir)->i_ino);
 		goto mark_error;
+	}
 
 	inode_unlock(d_inode(subdir));
 
@@ -224,9 +217,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 void cachefiles_put_directory(struct dentry *dir)
 {
 	if (dir) {
-		inode_lock(dir->d_inode);
-		__cachefiles_unmark_inode_in_use(NULL, dir);
-		inode_unlock(dir->d_inode);
+		cachefiles_do_unmark_inode_in_use(NULL, d_inode(dir));
 		dput(dir);
 	}
 }
@@ -410,7 +401,7 @@ int cachefiles_bury_object(struct cachefiles_cache *cache,
 					    "Rename failed with error %d", ret);
 	}
 
-	__cachefiles_unmark_inode_in_use(object, rep);
+	__cachefiles_unmark_inode_in_use(object, d_inode(rep));
 	unlock_rename(cache->graveyard, dir);
 	dput(grave);
 	_leave(" = 0");
@@ -451,84 +442,72 @@ struct file *cachefiles_create_tmpfile(struct cachefiles_object *object)
 	const struct cred *saved_cred;
 	struct dentry *fan = volume->fanout[(u8)object->cookie->key_hash];
 	struct file *file;
-	struct path path;
+	const struct path parentpath = { .mnt = cache->mnt, .dentry = fan };
 	uint64_t ni_size;
 	long ret;
 
 
 	cachefiles_begin_secure(cache, &saved_cred);
 
-	path.mnt = cache->mnt;
 	ret = cachefiles_inject_write_error();
-	if (ret == 0)
-		path.dentry = vfs_tmpfile(&init_user_ns, fan, S_IFREG, O_RDWR);
-	else
-		path.dentry = ERR_PTR(ret);
-	if (IS_ERR(path.dentry)) {
-		trace_cachefiles_vfs_error(object, d_inode(fan), PTR_ERR(path.dentry),
+	if (ret == 0) {
+		file = vfs_tmpfile_open(&init_user_ns, &parentpath, S_IFREG,
+					O_RDWR | O_LARGEFILE | O_DIRECT,
+					cache->cache_cred);
+		ret = PTR_ERR_OR_ZERO(file);
+	}
+	if (ret) {
+		trace_cachefiles_vfs_error(object, d_inode(fan), ret,
 					   cachefiles_trace_tmpfile_error);
-		if (PTR_ERR(path.dentry) == -EIO)
+		if (ret == -EIO)
 			cachefiles_io_error_obj(object, "Failed to create tmpfile");
-		file = ERR_CAST(path.dentry);
-		goto out;
+		goto err;
 	}
 
-	trace_cachefiles_tmpfile(object, d_backing_inode(path.dentry));
+	trace_cachefiles_tmpfile(object, file_inode(file));
 
-	if (!cachefiles_mark_inode_in_use(object, path.dentry)) {
-		file = ERR_PTR(-EBUSY);
-		goto out_dput;
-	}
+	/* This is a newly created file with no other possible user */
+	if (!cachefiles_mark_inode_in_use(object, file_inode(file)))
+		WARN_ON(1);
 
 	ret = cachefiles_ondemand_init_object(object);
-	if (ret < 0) {
-		file = ERR_PTR(ret);
-		goto out_unuse;
-	}
+	if (ret < 0)
+		goto err_unuse;
 
 	ni_size = object->cookie->object_size;
 	ni_size = round_up(ni_size, CACHEFILES_DIO_BLOCK_SIZE);
 
 	if (ni_size > 0) {
-		trace_cachefiles_trunc(object, d_backing_inode(path.dentry), 0, ni_size,
+		trace_cachefiles_trunc(object, file_inode(file), 0, ni_size,
 				       cachefiles_trunc_expand_tmpfile);
 		ret = cachefiles_inject_write_error();
 		if (ret == 0)
-			ret = vfs_truncate(&path, ni_size);
+			ret = vfs_truncate(&file->f_path, ni_size);
 		if (ret < 0) {
 			trace_cachefiles_vfs_error(
-				object, d_backing_inode(path.dentry), ret,
+				object, file_inode(file), ret,
 				cachefiles_trace_trunc_error);
-			file = ERR_PTR(ret);
-			goto out_unuse;
+			goto err_unuse;
 		}
 	}
 
-	file = open_with_fake_path(&path, O_RDWR | O_LARGEFILE | O_DIRECT,
-				   d_backing_inode(path.dentry), cache->cache_cred);
-	if (IS_ERR(file)) {
-		trace_cachefiles_vfs_error(object, d_backing_inode(path.dentry),
-					   PTR_ERR(file),
-					   cachefiles_trace_open_error);
-		goto out_unuse;
-	}
+	ret = -EINVAL;
 	if (unlikely(!file->f_op->read_iter) ||
 	    unlikely(!file->f_op->write_iter)) {
 		fput(file);
 		pr_notice("Cache does not support read_iter and write_iter\n");
-		file = ERR_PTR(-EINVAL);
-		goto out_unuse;
+		goto err_unuse;
 	}
-
-	goto out_dput;
-
-out_unuse:
-	cachefiles_do_unmark_inode_in_use(object, path.dentry);
-out_dput:
-	dput(path.dentry);
 out:
 	cachefiles_end_secure(cache, saved_cred);
 	return file;
+
+err_unuse:
+	cachefiles_do_unmark_inode_in_use(object, file_inode(file));
+	fput(file);
+err:
+	file = ERR_PTR(ret);
+	goto out;
 }
 
 /*
@@ -569,8 +548,11 @@ static bool cachefiles_open_file(struct cachefiles_object *object,
 
 	_enter("%pd", dentry);
 
-	if (!cachefiles_mark_inode_in_use(object, dentry))
+	if (!cachefiles_mark_inode_in_use(object, d_inode(dentry))) {
+		pr_notice("cachefiles: Inode already in use: %pd (B=%lx)\n",
+			  dentry, d_inode(dentry)->i_ino);
 		return false;
+	}
 
 	/* We need to open a file interface onto a data file now as we can't do
 	 * it on demand because writeback called from do_exit() sees
@@ -624,7 +606,7 @@ static bool cachefiles_open_file(struct cachefiles_object *object,
 error_fput:
 	fput(file);
 error:
-	cachefiles_do_unmark_inode_in_use(object, dentry);
+	cachefiles_do_unmark_inode_in_use(object, d_inode(dentry));
 	dput(dentry);
 	return false;
 }

fs/dcache.c

@@ -3249,8 +3249,10 @@ void d_genocide(struct dentry *parent)
 
 EXPORT_SYMBOL(d_genocide);
 
-void d_tmpfile(struct dentry *dentry, struct inode *inode)
+void d_tmpfile(struct file *file, struct inode *inode)
 {
+	struct dentry *dentry = file->f_path.dentry;
+
 	inode_dec_link_count(inode);
 	BUG_ON(dentry->d_name.name != dentry->d_iname ||
 		!hlist_unhashed(&dentry->d_u.d_alias) ||

fs/ext2/namei.c

@@ -120,17 +120,17 @@ static int ext2_create (struct user_namespace * mnt_userns,
 }
 
 static int ext2_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
-			struct dentry *dentry, umode_t mode)
+			struct file *file, umode_t mode)
 {
 	struct inode *inode = ext2_new_inode(dir, mode, NULL);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
 
 	ext2_set_file_ops(inode);
 	mark_inode_dirty(inode);
-	d_tmpfile(dentry, inode);
+	d_tmpfile(file, inode);
 	unlock_new_inode(inode);
-	return 0;
+	return finish_open_simple(file, 0);
 }
 
 static int ext2_mknod (struct user_namespace * mnt_userns, struct inode * dir,

fs/ext4/namei.c

@@ -2854,7 +2854,7 @@ static int ext4_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 }
 
 static int ext4_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
-			struct dentry *dentry, umode_t mode)
+			struct file *file, umode_t mode)
 {
 	handle_t *handle;
 	struct inode *inode;
@@ -2876,7 +2876,7 @@ static int ext4_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
 		inode->i_op = &ext4_file_inode_operations;
 		inode->i_fop = &ext4_file_operations;
 		ext4_set_aops(inode);
-		d_tmpfile(dentry, inode);
+		d_tmpfile(file, inode);
 		err = ext4_orphan_add(handle, inode);
 		if (err)
 			goto err_unlock_inode;
@@ -2887,7 +2887,7 @@ static int ext4_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
 		ext4_journal_stop(handle);
 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
 		goto retry;
-	return err;
+	return finish_open_simple(file, err);
 err_unlock_inode:
 	ext4_journal_stop(handle);
 	unlock_new_inode(inode);