*
*/
+#include <linux/cred.h>
#include <linux/file.h>
#include <linux/poll.h>
+#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/fs.h>
.get_sb = anon_inodefs_get_sb,
.kill_sb = kill_anon_super,
};
-static struct dentry_operations anon_inodefs_dentry_operations = {
+static const struct dentry_operations anon_inodefs_dentry_operations = {
.d_delete = anon_inodefs_delete_dentry,
};
+/*
+ * nop .set_page_dirty method so that people can use .page_mkwrite on
+ * anon inodes.
+ */
+static int anon_set_page_dirty(struct page *page)
+{
+ return 0;
+};
+
+static const struct address_space_operations anon_aops = {
+ .set_page_dirty = anon_set_page_dirty,
+};
+
/**
* anon_inode_getfd - creates a new file instance by hooking it up to an
* anonymous inode, and a dentry that describe the "class"
*
* Creates a new file by hooking it on a single inode. This is useful for files
* that do not need to have a full-fledged inode in order to operate correctly.
- * All the files created with anon_inode_getfd() will share a single inode,
+ * All the files created with anon_inode_getfile() will share a single inode,
* hence saving memory and avoiding code duplication for the file/inode/dentry
- * setup. Returns new descriptor or -error.
+ * setup. Returns the newly created file* or an error pointer.
*/
-int anon_inode_getfd(const char *name, const struct file_operations *fops,
- void *priv, int flags)
+struct file *anon_inode_getfile(const char *name,
+ const struct file_operations *fops,
+ void *priv, int flags)
{
struct qstr this;
struct dentry *dentry;
struct file *file;
- int error, fd;
+ int error;
if (IS_ERR(anon_inode_inode))
- return -ENODEV;
+ return ERR_PTR(-ENODEV);
- error = get_unused_fd_flags(flags);
- if (error < 0)
- return error;
- fd = error;
+ if (fops->owner && !try_module_get(fops->owner))
+ return ERR_PTR(-ENOENT);
/*
* Link the inode to a directory entry by creating a unique name
this.hash = 0;
dentry = d_alloc(anon_inode_mnt->mnt_sb->s_root, &this);
if (!dentry)
- goto err_put_unused_fd;
+ goto err_module;
/*
* We know the anon_inode inode count is always greater than zero,
file->f_version = 0;
file->private_data = priv;
+ return file;
+
+err_dput:
+ dput(dentry);
+err_module:
+ module_put(fops->owner);
+ return ERR_PTR(error);
+}
+EXPORT_SYMBOL_GPL(anon_inode_getfile);
+
+/**
+ * anon_inode_getfd - 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
+ *
+ * Creates a new file by hooking it on a single inode. This is useful for files
+ * that do not need to have a full-fledged inode in order to operate correctly.
+ * All the files created with anon_inode_getfd() will share a single inode,
+ * hence saving memory and avoiding code duplication for the file/inode/dentry
+ * setup. Returns new descriptor or an error code.
+ */
+int anon_inode_getfd(const char *name, const struct file_operations *fops,
+ void *priv, int flags)
+{
+ int error, fd;
+ struct file *file;
+
+ error = get_unused_fd_flags(flags);
+ if (error < 0)
+ return error;
+ fd = error;
+
+ file = anon_inode_getfile(name, fops, priv, flags);
+ if (IS_ERR(file)) {
+ error = PTR_ERR(file);
+ goto err_put_unused_fd;
+ }
fd_install(fd, file);
return fd;
-err_dput:
- dput(dentry);
err_put_unused_fd:
put_unused_fd(fd);
return error;
inode->i_fop = &anon_inode_fops;
+ inode->i_mapping->a_ops = &anon_aops;
+
/*
* Mark the inode dirty from the very beginning,
* that way it will never be moved to the dirty