Unverified Commit 0873add0 authored by Christian Brauner's avatar Christian Brauner
Browse files

file: prepare for new helper 



In order to add a helper to open files that aren't accounted split
alloc_file() and parts of alloc_file_pseudo() into helpers. One to
prepare a path, another one to setup the file.

Suggested-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240129160241.GA2793@lst.de


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 386dc41c

fs/file_table.c

+41 −18
Original line number Diff line number Diff line
@@ -276,21 +276,15 @@ struct file *alloc_empty_backing_file(int flags, const struct cred *cred) 
}



/**

 * alloc_file - allocate and initialize a 'struct file'

 * file_init_path - initialize a 'struct file' based on path

 *

 * @file: the file to set up

 * @path: the (dentry, vfsmount) pair for the new file

 * @flags: O_... flags with which the new file will be opened

 * @fop: the 'struct file_operations' for the new file

 */

static struct file *alloc_file(const struct path *path, int flags,

static void file_init_path(struct file *file, const struct path *path,

			   const struct file_operations *fop)

{

	struct file *file;



	file = alloc_empty_file(flags, current_cred());

	if (IS_ERR(file))

		return file;



	file->f_path = *path;

	file->f_inode = path->dentry->d_inode;

	file->f_mapping = path->dentry->d_inode->i_mapping;
@@ -309,22 +303,51 @@ static struct file *alloc_file(const struct path *path, int flags, 
	file->f_op = fop;

	if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)

		i_readcount_inc(path->dentry->d_inode);

}



/**

 * alloc_file - allocate and initialize a 'struct file'

 *

 * @path: the (dentry, vfsmount) pair for the new file

 * @flags: O_... flags with which the new file will be opened

 * @fop: the 'struct file_operations' for the new file

 */

static struct file *alloc_file(const struct path *path, int flags,

		const struct file_operations *fop)

{

	struct file *file;



	file = alloc_empty_file(flags, current_cred());

	if (!IS_ERR(file))

		file_init_path(file, path, fop);

	return file;

}



static inline int alloc_path_pseudo(const char *name, struct inode *inode,

				    struct vfsmount *mnt, struct path *path)

{

	struct qstr this = QSTR_INIT(name, strlen(name));



	path->dentry = d_alloc_pseudo(mnt->mnt_sb, &this);

	if (!path->dentry)

		return -ENOMEM;

	path->mnt = mntget(mnt);

	d_instantiate(path->dentry, inode);

	return 0;

}



struct file *alloc_file_pseudo(struct inode *inode, struct vfsmount *mnt,

			       const char *name, int flags,

			       const struct file_operations *fops)

{

	struct qstr this = QSTR_INIT(name, strlen(name));

	int ret;

	struct path path;

	struct file *file;



	path.dentry = d_alloc_pseudo(mnt->mnt_sb, &this);

	if (!path.dentry)

		return ERR_PTR(-ENOMEM);

	path.mnt = mntget(mnt);

	d_instantiate(path.dentry, inode);

	ret = alloc_path_pseudo(name, inode, mnt, &path);

	if (ret)

		return ERR_PTR(ret);



	file = alloc_file(&path, flags, fops);

	if (IS_ERR(file)) {

		ihold(inode);