*
*/
+#include <linux/cred.h>
#include <linux/file.h>
#include <linux/poll.h>
-#include <linux/slab.h>
+#include <linux/sched.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mount.h>
static struct inode *anon_inode_inode;
static const struct file_operations anon_inode_fops;
-static int anon_inodefs_get_sb(struct file_system_type *fs_type, int flags,
- const char *dev_name, void *data,
- struct vfsmount *mnt)
+/*
+ * anon_inodefs_dname() is called from d_path().
+ */
+static char *anon_inodefs_dname(struct dentry *dentry, char *buffer, int buflen)
{
- return get_sb_pseudo(fs_type, "anon_inode:", NULL, ANON_INODE_FS_MAGIC,
- mnt);
+ return dynamic_dname(dentry, buffer, buflen, "anon_inode:%s",
+ dentry->d_name.name);
}
-static int anon_inodefs_delete_dentry(struct dentry *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,
+};
+
+/*
+ * A single inode exists for all anon_inode files. Contrary to pipes,
+ * anon_inode inodes have no associated per-instance data, so we need
+ * only allocate one of them.
+ */
+static struct inode *anon_inode_mkinode(struct super_block *s)
+{
+ struct inode *inode = new_inode_pseudo(s);
+
+ if (!inode)
+ return ERR_PTR(-ENOMEM);
+
+ inode->i_ino = get_next_ino();
+ inode->i_fop = &anon_inode_fops;
+
+ inode->i_mapping->a_ops = &anon_aops;
+
/*
- * We faked vfs to believe the dentry was hashed when we created it.
- * Now we restore the flag so that dput() will work correctly.
+ * Mark the inode dirty from the very beginning,
+ * that way it will never be moved to the dirty
+ * list because mark_inode_dirty() will think
+ * that it already _is_ on the dirty list.
*/
- dentry->d_flags |= DCACHE_UNHASHED;
- return 1;
+ inode->i_state = I_DIRTY;
+ inode->i_mode = S_IRUSR | S_IWUSR;
+ inode->i_uid = current_fsuid();
+ inode->i_gid = current_fsgid();
+ inode->i_flags |= S_PRIVATE;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ return inode;
+}
+
+static struct dentry *anon_inodefs_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
+{
+ struct dentry *root;
+ root = mount_pseudo(fs_type, "anon_inode:", NULL,
+ &anon_inodefs_dentry_operations, ANON_INODE_FS_MAGIC);
+ if (!IS_ERR(root)) {
+ struct super_block *s = root->d_sb;
+ anon_inode_inode = anon_inode_mkinode(s);
+ if (IS_ERR(anon_inode_inode)) {
+ dput(root);
+ deactivate_locked_super(s);
+ root = ERR_CAST(anon_inode_inode);
+ }
+ }
+ return root;
}
static struct file_system_type anon_inode_fs_type = {
.name = "anon_inodefs",
- .get_sb = anon_inodefs_get_sb,
+ .mount = anon_inodefs_mount,
.kill_sb = kill_anon_super,
};
-static struct dentry_operations anon_inodefs_dentry_operations = {
- .d_delete = anon_inodefs_delete_dentry,
-};
/**
- * anon_inode_getfd - creates a new file instance by hooking it up to and
- * anonymous inode, and a dentry that describe the "class"
- * of the file
+ * anon_inode_getfile - creates a new file instance by hooking it up to an
+ * anonymous inode, and a dentry that describe the "class"
+ * of the file
*
- * @pfd: [out] pointer to the file descriptor
- * @dpinode: [out] pointer to the inode
- * @pfile: [out] pointer to the file struct
* @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)
+ * @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, by
+ * 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.
+ * setup. Returns the newly created file* or an error pointer.
*/
-int anon_inode_getfd(int *pfd, struct inode **pinode, struct file **pfile,
- const char *name, const struct file_operations *fops,
- void *priv)
+struct file *anon_inode_getfile(const char *name,
+ const struct file_operations *fops,
+ void *priv, int flags)
{
struct qstr this;
- struct dentry *dentry;
- struct inode *inode;
+ struct path path;
struct file *file;
- int error, fd;
+ int error;
if (IS_ERR(anon_inode_inode))
- return -ENODEV;
- file = get_empty_filp();
- if (!file)
- return -ENFILE;
+ return ERR_PTR(-ENODEV);
- inode = igrab(anon_inode_inode);
- if (IS_ERR(inode)) {
- error = PTR_ERR(inode);
- goto err_put_filp;
- }
-
- error = get_unused_fd();
- if (error < 0)
- goto err_iput;
- 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.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;
- 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, inode);
+ path.dentry = d_alloc_pseudo(anon_inode_mnt->mnt_sb, &this);
+ if (!path.dentry)
+ goto err_module;
- file->f_path.mnt = mntget(anon_inode_mnt);
- file->f_path.dentry = dentry;
- file->f_mapping = inode->i_mapping;
+ path.mnt = mntget(anon_inode_mnt);
+ /*
+ * We know the anon_inode inode count is always greater than zero,
+ * so ihold() is safe.
+ */
+ ihold(anon_inode_inode);
+
+ d_instantiate(path.dentry, anon_inode_inode);
+
+ error = -ENFILE;
+ 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;
- file->f_op = fops;
- file->f_mode = FMODE_READ | FMODE_WRITE;
+ file->f_flags = flags & (O_ACCMODE | O_NONBLOCK);
file->f_version = 0;
file->private_data = priv;
- fd_install(fd, file);
-
- *pfd = fd;
- *pinode = inode;
- *pfile = file;
- return 0;
+ return file;
-err_put_unused_fd:
- put_unused_fd(fd);
-err_iput:
- iput(inode);
-err_put_filp:
- put_filp(file);
- return error;
+err_dput:
+ path_put(&path);
+err_module:
+ module_put(fops->owner);
+ return ERR_PTR(error);
}
+EXPORT_SYMBOL_GPL(anon_inode_getfile);
-/*
- * A single inode exist for all anon_inode files. Contrary to pipes,
- * anon_inode inodes has no per-instance data associated, so we can avoid
- * the allocation of multiple of them.
+/**
+ * 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.
*/
-static struct inode *anon_inode_mkinode(void)
+int anon_inode_getfd(const char *name, const struct file_operations *fops,
+ void *priv, int flags)
{
- struct inode *inode = new_inode(anon_inode_mnt->mnt_sb);
+ int error, fd;
+ struct file *file;
- if (!inode)
- return ERR_PTR(-ENOMEM);
+ error = get_unused_fd_flags(flags);
+ if (error < 0)
+ return error;
+ fd = error;
- inode->i_fop = &anon_inode_fops;
+ 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);
- /*
- * Mark the inode dirty from the very beginning,
- * that way it will never be moved to the dirty
- * list because mark_inode_dirty() will think
- * that it already _is_ on the dirty list.
- */
- inode->i_state = I_DIRTY;
- inode->i_mode = S_IRUSR | S_IWUSR;
- inode->i_uid = current->fsuid;
- inode->i_gid = current->fsgid;
- inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
- return inode;
+ return fd;
+
+err_put_unused_fd:
+ put_unused_fd(fd);
+ return error;
}
+EXPORT_SYMBOL_GPL(anon_inode_getfd);
static int __init anon_inode_init(void)
{
error = PTR_ERR(anon_inode_mnt);
goto err_unregister_filesystem;
}
- anon_inode_inode = anon_inode_mkinode();
- if (IS_ERR(anon_inode_inode)) {
- error = PTR_ERR(anon_inode_inode);
- goto err_mntput;
- }
-
return 0;
-err_mntput:
- mntput(anon_inode_mnt);
err_unregister_filesystem:
unregister_filesystem(&anon_inode_fs_type);
err_exit:
Code Review / linux-2.6.git / blobdiff