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Commit 55708698 authored by Gu Zheng's avatar Gu Zheng Committed by Benjamin LaHaise
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fs/anon_inode: Introduce a new lib function anon_inode_getfile_private() 



Introduce a new lib function anon_inode_getfile_private(), it creates a new file
instance by hooking it up to an anonymous inode, and a dentry that describe the
"class" of the file, similar to anon_inode_getfile(), but each file holds a
single inode. Furthermore, anyone who wants to create a private anon file will
benefit from this change.

Signed-off-by: default avatarGu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: default avatarBenjamin LaHaise <bcrl@kvack.org>
parent 47188d39

fs/anon_inodes.c

+66 −0
Original line number Diff line number Diff line
@@ -108,6 +108,72 @@ static struct file_system_type anon_inode_fs_type = { 
	.kill_sb	= kill_anon_super,

};



/**

 * anon_inode_getfile_private - creates a new file instance by hooking it up to an

 *                      anonymous inode, and a dentry that describe the "class"

 *                      of the file

 *

 * @name:    [in]    name of the "class" of the new file

 * @fops:    [in]    file operations for the new file

 * @priv:    [in]    private data for the new file (will be file's private_data)

 * @flags:   [in]    flags

 *

 *

 * Similar to anon_inode_getfile, but each file holds a single inode.

 *

 */

struct file *anon_inode_getfile_private(const char *name,

					const struct file_operations *fops,

					void *priv, int flags)

{

	struct qstr this;

	struct path path;

	struct file *file;

	struct inode *inode;



	if (fops->owner && !try_module_get(fops->owner))

		return ERR_PTR(-ENOENT);



	inode = anon_inode_mkinode(anon_inode_mnt->mnt_sb);

	if (IS_ERR(inode)) {

		file = ERR_PTR(-ENOMEM);

		goto err_module;

	}



	/*

	 * Link the inode to a directory entry by creating a unique name

	 * using the inode sequence number.

	 */

	file = ERR_PTR(-ENOMEM);

	this.name = name;

	this.len = strlen(name);

	this.hash = 0;

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

	if (!path.dentry)

		goto err_module;



	path.mnt = mntget(anon_inode_mnt);



	d_instantiate(path.dentry, inode);



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

	if (IS_ERR(file))

		goto err_dput;



	file->f_mapping = inode->i_mapping;

	file->f_flags = flags & (O_ACCMODE | O_NONBLOCK);

	file->private_data = priv;



	return file;



err_dput:

	path_put(&path);

err_module:

	module_put(fops->owner);

	return file;

}

EXPORT_SYMBOL_GPL(anon_inode_getfile_private);



/**

 * anon_inode_getfile - creates a new file instance by hooking it up to an

 *                      anonymous inode, and a dentry that describe the "class"

include/linux/anon_inodes.h

+3 −0
Original line number Diff line number Diff line
@@ -13,6 +13,9 @@ struct file_operations; 
struct file *anon_inode_getfile(const char *name,

				const struct file_operations *fops,

				void *priv, int flags);

struct file *anon_inode_getfile_private(const char *name,

				const struct file_operations *fops,

				void *priv, int flags);

int anon_inode_getfd(const char *name, const struct file_operations *fops,

		     void *priv, int flags);