*
*/
+#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>
mnt);
}
-static int anon_inodefs_delete_dentry(struct dentry *dentry)
+/*
+ * anon_inodefs_dname() is called from d_path().
+ */
+static char *anon_inodefs_dname(struct dentry *dentry, char *buffer, int buflen)
{
- /*
- * We faked vfs to believe the dentry was hashed when we created it.
- * Now we restore the flag so that dput() will work correctly.
- */
- dentry->d_flags |= DCACHE_UNHASHED;
- return 1;
+ return dynamic_dname(dentry, buffer, buflen, "anon_inode:%s",
+ dentry->d_name.name);
}
static struct file_system_type anon_inode_fs_type = {
.get_sb = anon_inodefs_get_sb,
.kill_sb = kill_anon_super,
};
-static struct dentry_operations anon_inodefs_dentry_operations = {
- .d_delete = anon_inodefs_delete_dentry,
+static const struct dentry_operations anon_inodefs_dentry_operations = {
+ .d_dname = anon_inodefs_dname,
+};
+
+/*
+ * 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,
};
/**
*
* 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 path path;
struct file *file;
- int error, fd;
+ int error;
if (IS_ERR(anon_inode_inode))
- return -ENODEV;
+ return ERR_PTR(-ENODEV);
if (fops->owner && !try_module_get(fops->owner))
- return -ENOENT;
-
- error = get_unused_fd_flags(flags);
- if (error < 0)
- goto err_module;
- fd = error;
+ return ERR_PTR(-ENOENT);
/*
* Link the inode to a directory entry by creating a unique name
this.name = name;
this.len = strlen(name);
this.hash = 0;
- dentry = d_alloc(anon_inode_mnt->mnt_sb->s_root, &this);
- if (!dentry)
- goto err_put_unused_fd;
+ path.dentry = d_alloc(anon_inode_mnt->mnt_sb->s_root, &this);
+ if (!path.dentry)
+ goto err_module;
+ path.mnt = mntget(anon_inode_mnt);
/*
* We know the anon_inode inode count is always greater than zero,
* so we can avoid doing an igrab() and we can use an open-coded
*/
atomic_inc(&anon_inode_inode->i_count);
- dentry->d_op = &anon_inodefs_dentry_operations;
- /* Do not publish this dentry inside the global dentry hash table */
- dentry->d_flags &= ~DCACHE_UNHASHED;
- d_instantiate(dentry, anon_inode_inode);
+ path.dentry->d_op = &anon_inodefs_dentry_operations;
+ d_instantiate(path.dentry, anon_inode_inode);
error = -ENFILE;
- file = alloc_file(anon_inode_mnt, dentry,
- FMODE_READ | FMODE_WRITE, fops);
+ file = alloc_file(&path, OPEN_FMODE(flags), fops);
if (!file)
goto err_dput;
file->f_mapping = anon_inode_inode->i_mapping;
file->f_pos = 0;
- file->f_flags = O_RDWR | (flags & O_NONBLOCK);
+ file->f_flags = flags & (O_ACCMODE | O_NONBLOCK);
file->f_version = 0;
file->private_data = priv;
+ return file;
+
+err_dput:
+ path_put(&path);
+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);
-err_module:
- module_put(fops->owner);
return error;
}
EXPORT_SYMBOL_GPL(anon_inode_getfd);
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
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff