[PATCH] configfs: User-driven configuration filesystem
Configfs, a file system for userspace-driven kernel object configuration. The OCFS2 stack makes extensive use of this for propagation of cluster configuration information into kernel. Signed-off-by: Joel Becker <joel.becker@oracle.com>
This commit is contained in:
Joel Becker
7
fs/configfs/Makefile
Normal file
7
fs/configfs/Makefile
Normal file
@ -0,0 +1,7 @@
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#
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# Makefile for the configfs virtual filesystem
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#
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obj-$(CONFIG_CONFIGFS_FS) += configfs.o
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configfs-objs := inode.o file.o dir.o symlink.o mount.o item.o
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142
fs/configfs/configfs_internal.h
Normal file
142
fs/configfs/configfs_internal.h
Normal file
@ -0,0 +1,142 @@
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/* -*- mode: c; c-basic-offset:8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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*
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* configfs_internal.h - Internal stuff for configfs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*
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* Based on sysfs:
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* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
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*
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* configfs Copyright (C) 2005 Oracle. All rights reserved.
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*/
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#include <linux/slab.h>
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#include <linux/list.h>
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struct configfs_dirent {
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atomic_t s_count;
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struct list_head s_sibling;
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struct list_head s_children;
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struct list_head s_links;
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void * s_element;
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int s_type;
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umode_t s_mode;
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struct dentry * s_dentry;
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};
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#define CONFIGFS_ROOT 0x0001
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#define CONFIGFS_DIR 0x0002
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#define CONFIGFS_ITEM_ATTR 0x0004
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#define CONFIGFS_ITEM_LINK 0x0020
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#define CONFIGFS_USET_DIR 0x0040
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#define CONFIGFS_USET_DEFAULT 0x0080
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#define CONFIGFS_USET_DROPPING 0x0100
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#define CONFIGFS_NOT_PINNED (CONFIGFS_ITEM_ATTR)
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extern struct vfsmount * configfs_mount;
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extern int configfs_is_root(struct config_item *item);
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extern struct inode * configfs_new_inode(mode_t mode);
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extern int configfs_create(struct dentry *, int mode, int (*init)(struct inode *));
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extern int configfs_create_file(struct config_item *, const struct configfs_attribute *);
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extern int configfs_make_dirent(struct configfs_dirent *,
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struct dentry *, void *, umode_t, int);
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extern int configfs_add_file(struct dentry *, const struct configfs_attribute *, int);
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extern void configfs_hash_and_remove(struct dentry * dir, const char * name);
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extern const unsigned char * configfs_get_name(struct configfs_dirent *sd);
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extern void configfs_drop_dentry(struct configfs_dirent *sd, struct dentry *parent);
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extern int configfs_pin_fs(void);
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extern void configfs_release_fs(void);
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extern struct rw_semaphore configfs_rename_sem;
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extern struct super_block * configfs_sb;
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extern struct file_operations configfs_dir_operations;
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extern struct file_operations configfs_file_operations;
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extern struct file_operations bin_fops;
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extern struct inode_operations configfs_dir_inode_operations;
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extern struct inode_operations configfs_symlink_inode_operations;
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extern int configfs_symlink(struct inode *dir, struct dentry *dentry,
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const char *symname);
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extern int configfs_unlink(struct inode *dir, struct dentry *dentry);
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struct configfs_symlink {
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struct list_head sl_list;
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struct config_item *sl_target;
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};
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extern int configfs_create_link(struct configfs_symlink *sl,
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struct dentry *parent,
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struct dentry *dentry);
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static inline struct config_item * to_item(struct dentry * dentry)
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{
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struct configfs_dirent * sd = dentry->d_fsdata;
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return ((struct config_item *) sd->s_element);
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}
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static inline struct configfs_attribute * to_attr(struct dentry * dentry)
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{
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struct configfs_dirent * sd = dentry->d_fsdata;
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return ((struct configfs_attribute *) sd->s_element);
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}
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static inline struct config_item *configfs_get_config_item(struct dentry *dentry)
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{
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struct config_item * item = NULL;
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spin_lock(&dcache_lock);
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if (!d_unhashed(dentry)) {
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struct configfs_dirent * sd = dentry->d_fsdata;
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if (sd->s_type & CONFIGFS_ITEM_LINK) {
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struct configfs_symlink * sl = sd->s_element;
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item = config_item_get(sl->sl_target);
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} else
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item = config_item_get(sd->s_element);
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}
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spin_unlock(&dcache_lock);
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return item;
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}
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static inline void release_configfs_dirent(struct configfs_dirent * sd)
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{
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if (!(sd->s_type & CONFIGFS_ROOT))
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kfree(sd);
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}
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static inline struct configfs_dirent * configfs_get(struct configfs_dirent * sd)
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{
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if (sd) {
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WARN_ON(!atomic_read(&sd->s_count));
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atomic_inc(&sd->s_count);
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}
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return sd;
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}
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static inline void configfs_put(struct configfs_dirent * sd)
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{
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WARN_ON(!atomic_read(&sd->s_count));
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if (atomic_dec_and_test(&sd->s_count))
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release_configfs_dirent(sd);
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}
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1102
fs/configfs/dir.c
Normal file
1102
fs/configfs/dir.c
Normal file
File diff suppressed because it is too large
Load Diff
360
fs/configfs/file.c
Normal file
360
fs/configfs/file.c
Normal file
@ -0,0 +1,360 @@
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/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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*
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* file.c - operations for regular (text) files.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
|
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*
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* You should have received a copy of the GNU General Public
|
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*
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* Based on sysfs:
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* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
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*
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* configfs Copyright (C) 2005 Oracle. All rights reserved.
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*/
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#include <linux/fs.h>
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#include <linux/module.h>
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#include <linux/dnotify.h>
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#include <linux/slab.h>
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#include <asm/uaccess.h>
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#include <asm/semaphore.h>
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#include <linux/configfs.h>
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#include "configfs_internal.h"
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struct configfs_buffer {
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size_t count;
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loff_t pos;
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char * page;
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struct configfs_item_operations * ops;
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struct semaphore sem;
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int needs_read_fill;
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};
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/**
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* fill_read_buffer - allocate and fill buffer from item.
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* @dentry: dentry pointer.
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* @buffer: data buffer for file.
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*
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* Allocate @buffer->page, if it hasn't been already, then call the
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* config_item's show() method to fill the buffer with this attribute's
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* data.
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* This is called only once, on the file's first read.
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*/
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static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buffer)
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{
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struct configfs_attribute * attr = to_attr(dentry);
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struct config_item * item = to_item(dentry->d_parent);
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struct configfs_item_operations * ops = buffer->ops;
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int ret = 0;
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ssize_t count;
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if (!buffer->page)
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buffer->page = (char *) get_zeroed_page(GFP_KERNEL);
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if (!buffer->page)
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return -ENOMEM;
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count = ops->show_attribute(item,attr,buffer->page);
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buffer->needs_read_fill = 0;
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BUG_ON(count > (ssize_t)PAGE_SIZE);
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if (count >= 0)
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buffer->count = count;
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else
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ret = count;
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return ret;
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}
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/**
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* flush_read_buffer - push buffer to userspace.
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* @buffer: data buffer for file.
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* @userbuf: user-passed buffer.
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* @count: number of bytes requested.
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* @ppos: file position.
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*
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* Copy the buffer we filled in fill_read_buffer() to userspace.
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* This is done at the reader's leisure, copying and advancing
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* the amount they specify each time.
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* This may be called continuously until the buffer is empty.
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*/
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static int flush_read_buffer(struct configfs_buffer * buffer, char __user * buf,
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size_t count, loff_t * ppos)
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{
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int error;
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if (*ppos > buffer->count)
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return 0;
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if (count > (buffer->count - *ppos))
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count = buffer->count - *ppos;
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error = copy_to_user(buf,buffer->page + *ppos,count);
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if (!error)
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*ppos += count;
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return error ? -EFAULT : count;
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}
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/**
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* configfs_read_file - read an attribute.
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* @file: file pointer.
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* @buf: buffer to fill.
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* @count: number of bytes to read.
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* @ppos: starting offset in file.
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*
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* Userspace wants to read an attribute file. The attribute descriptor
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* is in the file's ->d_fsdata. The target item is in the directory's
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* ->d_fsdata.
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*
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* We call fill_read_buffer() to allocate and fill the buffer from the
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* item's show() method exactly once (if the read is happening from
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* the beginning of the file). That should fill the entire buffer with
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* all the data the item has to offer for that attribute.
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* We then call flush_read_buffer() to copy the buffer to userspace
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* in the increments specified.
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*/
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static ssize_t
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configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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{
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struct configfs_buffer * buffer = file->private_data;
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ssize_t retval = 0;
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down(&buffer->sem);
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if (buffer->needs_read_fill) {
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if ((retval = fill_read_buffer(file->f_dentry,buffer)))
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goto out;
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}
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pr_debug("%s: count = %d, ppos = %lld, buf = %s\n",
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__FUNCTION__,count,*ppos,buffer->page);
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retval = flush_read_buffer(buffer,buf,count,ppos);
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out:
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up(&buffer->sem);
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return retval;
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}
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/**
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* fill_write_buffer - copy buffer from userspace.
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* @buffer: data buffer for file.
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* @userbuf: data from user.
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* @count: number of bytes in @userbuf.
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*
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* Allocate @buffer->page if it hasn't been already, then
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* copy the user-supplied buffer into it.
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*/
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static int
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fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size_t count)
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{
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int error;
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if (!buffer->page)
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buffer->page = (char *)get_zeroed_page(GFP_KERNEL);
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if (!buffer->page)
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return -ENOMEM;
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|
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if (count > PAGE_SIZE)
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count = PAGE_SIZE;
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error = copy_from_user(buffer->page,buf,count);
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buffer->needs_read_fill = 1;
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return error ? -EFAULT : count;
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}
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|
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/**
|
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* flush_write_buffer - push buffer to config_item.
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* @file: file pointer.
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* @buffer: data buffer for file.
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*
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* Get the correct pointers for the config_item and the attribute we're
|
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* dealing with, then call the store() method for the attribute,
|
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* passing the buffer that we acquired in fill_write_buffer().
|
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*/
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|
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static int
|
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flush_write_buffer(struct dentry * dentry, struct configfs_buffer * buffer, size_t count)
|
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{
|
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struct configfs_attribute * attr = to_attr(dentry);
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struct config_item * item = to_item(dentry->d_parent);
|
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struct configfs_item_operations * ops = buffer->ops;
|
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|
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return ops->store_attribute(item,attr,buffer->page,count);
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}
|
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|
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|
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/**
|
||||
* configfs_write_file - write an attribute.
|
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* @file: file pointer
|
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* @buf: data to write
|
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* @count: number of bytes
|
||||
* @ppos: starting offset
|
||||
*
|
||||
* Similar to configfs_read_file(), though working in the opposite direction.
|
||||
* We allocate and fill the data from the user in fill_write_buffer(),
|
||||
* then push it to the config_item in flush_write_buffer().
|
||||
* There is no easy way for us to know if userspace is only doing a partial
|
||||
* write, so we don't support them. We expect the entire buffer to come
|
||||
* on the first write.
|
||||
* Hint: if you're writing a value, first read the file, modify only the
|
||||
* the value you're changing, then write entire buffer back.
|
||||
*/
|
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|
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static ssize_t
|
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configfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
|
||||
{
|
||||
struct configfs_buffer * buffer = file->private_data;
|
||||
|
||||
down(&buffer->sem);
|
||||
count = fill_write_buffer(buffer,buf,count);
|
||||
if (count > 0)
|
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count = flush_write_buffer(file->f_dentry,buffer,count);
|
||||
if (count > 0)
|
||||
*ppos += count;
|
||||
up(&buffer->sem);
|
||||
return count;
|
||||
}
|
||||
|
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static int check_perm(struct inode * inode, struct file * file)
|
||||
{
|
||||
struct config_item *item = configfs_get_config_item(file->f_dentry->d_parent);
|
||||
struct configfs_attribute * attr = to_attr(file->f_dentry);
|
||||
struct configfs_buffer * buffer;
|
||||
struct configfs_item_operations * ops = NULL;
|
||||
int error = 0;
|
||||
|
||||
if (!item || !attr)
|
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goto Einval;
|
||||
|
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/* Grab the module reference for this attribute if we have one */
|
||||
if (!try_module_get(attr->ca_owner)) {
|
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error = -ENODEV;
|
||||
goto Done;
|
||||
}
|
||||
|
||||
if (item->ci_type)
|
||||
ops = item->ci_type->ct_item_ops;
|
||||
else
|
||||
goto Eaccess;
|
||||
|
||||
/* File needs write support.
|
||||
* The inode's perms must say it's ok,
|
||||
* and we must have a store method.
|
||||
*/
|
||||
if (file->f_mode & FMODE_WRITE) {
|
||||
|
||||
if (!(inode->i_mode & S_IWUGO) || !ops->store_attribute)
|
||||
goto Eaccess;
|
||||
|
||||
}
|
||||
|
||||
/* File needs read support.
|
||||
* The inode's perms must say it's ok, and we there
|
||||
* must be a show method for it.
|
||||
*/
|
||||
if (file->f_mode & FMODE_READ) {
|
||||
if (!(inode->i_mode & S_IRUGO) || !ops->show_attribute)
|
||||
goto Eaccess;
|
||||
}
|
||||
|
||||
/* No error? Great, allocate a buffer for the file, and store it
|
||||
* it in file->private_data for easy access.
|
||||
*/
|
||||
buffer = kmalloc(sizeof(struct configfs_buffer),GFP_KERNEL);
|
||||
if (buffer) {
|
||||
memset(buffer,0,sizeof(struct configfs_buffer));
|
||||
init_MUTEX(&buffer->sem);
|
||||
buffer->needs_read_fill = 1;
|
||||
buffer->ops = ops;
|
||||
file->private_data = buffer;
|
||||
} else
|
||||
error = -ENOMEM;
|
||||
goto Done;
|
||||
|
||||
Einval:
|
||||
error = -EINVAL;
|
||||
goto Done;
|
||||
Eaccess:
|
||||
error = -EACCES;
|
||||
module_put(attr->ca_owner);
|
||||
Done:
|
||||
if (error && item)
|
||||
config_item_put(item);
|
||||
return error;
|
||||
}
|
||||
|
||||
static int configfs_open_file(struct inode * inode, struct file * filp)
|
||||
{
|
||||
return check_perm(inode,filp);
|
||||
}
|
||||
|
||||
static int configfs_release(struct inode * inode, struct file * filp)
|
||||
{
|
||||
struct config_item * item = to_item(filp->f_dentry->d_parent);
|
||||
struct configfs_attribute * attr = to_attr(filp->f_dentry);
|
||||
struct module * owner = attr->ca_owner;
|
||||
struct configfs_buffer * buffer = filp->private_data;
|
||||
|
||||
if (item)
|
||||
config_item_put(item);
|
||||
/* After this point, attr should not be accessed. */
|
||||
module_put(owner);
|
||||
|
||||
if (buffer) {
|
||||
if (buffer->page)
|
||||
free_page((unsigned long)buffer->page);
|
||||
kfree(buffer);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
struct file_operations configfs_file_operations = {
|
||||
.read = configfs_read_file,
|
||||
.write = configfs_write_file,
|
||||
.llseek = generic_file_llseek,
|
||||
.open = configfs_open_file,
|
||||
.release = configfs_release,
|
||||
};
|
||||
|
||||
|
||||
int configfs_add_file(struct dentry * dir, const struct configfs_attribute * attr, int type)
|
||||
{
|
||||
struct configfs_dirent * parent_sd = dir->d_fsdata;
|
||||
umode_t mode = (attr->ca_mode & S_IALLUGO) | S_IFREG;
|
||||
int error = 0;
|
||||
|
||||
down(&dir->d_inode->i_sem);
|
||||
error = configfs_make_dirent(parent_sd, NULL, (void *) attr, mode, type);
|
||||
up(&dir->d_inode->i_sem);
|
||||
|
||||
return error;
|
||||
}
|
||||
|
||||
|
||||
/**
|
||||
* configfs_create_file - create an attribute file for an item.
|
||||
* @item: item we're creating for.
|
||||
* @attr: atrribute descriptor.
|
||||
*/
|
||||
|
||||
int configfs_create_file(struct config_item * item, const struct configfs_attribute * attr)
|
||||
{
|
||||
BUG_ON(!item || !item->ci_dentry || !attr);
|
||||
|
||||
return configfs_add_file(item->ci_dentry, attr,
|
||||
CONFIGFS_ITEM_ATTR);
|
||||
}
|
||||
|
||||
162
fs/configfs/inode.c
Normal file
162
fs/configfs/inode.c
Normal file
@ -0,0 +1,162 @@
|
||||
/* -*- mode: c; c-basic-offset: 8; -*-
|
||||
* vim: noexpandtab sw=8 ts=8 sts=0:
|
||||
*
|
||||
* inode.c - basic inode and dentry operations.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public
|
||||
* License as published by the Free Software Foundation; either
|
||||
* version 2 of the License, or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
* General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public
|
||||
* License along with this program; if not, write to the
|
||||
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
||||
* Boston, MA 021110-1307, USA.
|
||||
*
|
||||
* Based on sysfs:
|
||||
* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
|
||||
*
|
||||
* configfs Copyright (C) 2005 Oracle. All rights reserved.
|
||||
*
|
||||
* Please see Documentation/filesystems/configfs.txt for more information.
|
||||
*/
|
||||
|
||||
#undef DEBUG
|
||||
|
||||
#include <linux/pagemap.h>
|
||||
#include <linux/namei.h>
|
||||
#include <linux/backing-dev.h>
|
||||
|
||||
#include <linux/configfs.h>
|
||||
#include "configfs_internal.h"
|
||||
|
||||
extern struct super_block * configfs_sb;
|
||||
|
||||
static struct address_space_operations configfs_aops = {
|
||||
.readpage = simple_readpage,
|
||||
.prepare_write = simple_prepare_write,
|
||||
.commit_write = simple_commit_write
|
||||
};
|
||||
|
||||
static struct backing_dev_info configfs_backing_dev_info = {
|
||||
.ra_pages = 0, /* No readahead */
|
||||
.capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
|
||||
};
|
||||
|
||||
struct inode * configfs_new_inode(mode_t mode)
|
||||
{
|
||||
struct inode * inode = new_inode(configfs_sb);
|
||||
if (inode) {
|
||||
inode->i_mode = mode;
|
||||
inode->i_uid = 0;
|
||||
inode->i_gid = 0;
|
||||
inode->i_blksize = PAGE_CACHE_SIZE;
|
||||
inode->i_blocks = 0;
|
||||
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
|
||||
inode->i_mapping->a_ops = &configfs_aops;
|
||||
inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
|
||||
}
|
||||
return inode;
|
||||
}
|
||||
|
||||
int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
|
||||
{
|
||||
int error = 0;
|
||||
struct inode * inode = NULL;
|
||||
if (dentry) {
|
||||
if (!dentry->d_inode) {
|
||||
if ((inode = configfs_new_inode(mode))) {
|
||||
if (dentry->d_parent && dentry->d_parent->d_inode) {
|
||||
struct inode *p_inode = dentry->d_parent->d_inode;
|
||||
p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
|
||||
}
|
||||
goto Proceed;
|
||||
}
|
||||
else
|
||||
error = -ENOMEM;
|
||||
} else
|
||||
error = -EEXIST;
|
||||
} else
|
||||
error = -ENOENT;
|
||||
goto Done;
|
||||
|
||||
Proceed:
|
||||
if (init)
|
||||
error = init(inode);
|
||||
if (!error) {
|
||||
d_instantiate(dentry, inode);
|
||||
if (S_ISDIR(mode) || S_ISLNK(mode))
|
||||
dget(dentry); /* pin link and directory dentries in core */
|
||||
} else
|
||||
iput(inode);
|
||||
Done:
|
||||
return error;
|
||||
}
|
||||
|
||||
/*
|
||||
* Get the name for corresponding element represented by the given configfs_dirent
|
||||
*/
|
||||
const unsigned char * configfs_get_name(struct configfs_dirent *sd)
|
||||
{
|
||||
struct attribute * attr;
|
||||
|
||||
if (!sd || !sd->s_element)
|
||||
BUG();
|
||||
|
||||
/* These always have a dentry, so use that */
|
||||
if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
|
||||
return sd->s_dentry->d_name.name;
|
||||
|
||||
if (sd->s_type & CONFIGFS_ITEM_ATTR) {
|
||||
attr = sd->s_element;
|
||||
return attr->name;
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Unhashes the dentry corresponding to given configfs_dirent
|
||||
* Called with parent inode's i_sem held.
|
||||
*/
|
||||
void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
|
||||
{
|
||||
struct dentry * dentry = sd->s_dentry;
|
||||
|
||||
if (dentry) {
|
||||
spin_lock(&dcache_lock);
|
||||
if (!(d_unhashed(dentry) && dentry->d_inode)) {
|
||||
dget_locked(dentry);
|
||||
__d_drop(dentry);
|
||||
spin_unlock(&dcache_lock);
|
||||
simple_unlink(parent->d_inode, dentry);
|
||||
} else
|
||||
spin_unlock(&dcache_lock);
|
||||
}
|
||||
}
|
||||
|
||||
void configfs_hash_and_remove(struct dentry * dir, const char * name)
|
||||
{
|
||||
struct configfs_dirent * sd;
|
||||
struct configfs_dirent * parent_sd = dir->d_fsdata;
|
||||
|
||||
down(&dir->d_inode->i_sem);
|
||||
list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
|
||||
if (!sd->s_element)
|
||||
continue;
|
||||
if (!strcmp(configfs_get_name(sd), name)) {
|
||||
list_del_init(&sd->s_sibling);
|
||||
configfs_drop_dentry(sd, dir);
|
||||
configfs_put(sd);
|
||||
break;
|
||||
}
|
||||
}
|
||||
up(&dir->d_inode->i_sem);
|
||||
}
|
||||
|
||||
|
||||
227
fs/configfs/item.c
Normal file
227
fs/configfs/item.c
Normal file
@ -0,0 +1,227 @@
|
||||
/* -*- mode: c; c-basic-offset: 8; -*-
|
||||
* vim: noexpandtab sw=8 ts=8 sts=0:
|
||||
*
|
||||
* item.c - library routines for handling generic config items
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public
|
||||
* License as published by the Free Software Foundation; either
|
||||
* version 2 of the License, or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
* General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public
|
||||
* License along with this program; if not, write to the
|
||||
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
||||
* Boston, MA 021110-1307, USA.
|
||||
*
|
||||
* Based on kobject:
|
||||
* kobject is Copyright (c) 2002-2003 Patrick Mochel
|
||||
*
|
||||
* configfs Copyright (C) 2005 Oracle. All rights reserved.
|
||||
*
|
||||
* Please see the file Documentation/filesystems/configfs.txt for
|
||||
* critical information about using the config_item interface.
|
||||
*/
|
||||
|
||||
#include <linux/string.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/stat.h>
|
||||
#include <linux/slab.h>
|
||||
|
||||
#include <linux/configfs.h>
|
||||
|
||||
|
||||
static inline struct config_item * to_item(struct list_head * entry)
|
||||
{
|
||||
return container_of(entry,struct config_item,ci_entry);
|
||||
}
|
||||
|
||||
/* Evil kernel */
|
||||
static void config_item_release(struct kref *kref);
|
||||
|
||||
/**
|
||||
* config_item_init - initialize item.
|
||||
* @item: item in question.
|
||||
*/
|
||||
void config_item_init(struct config_item * item)
|
||||
{
|
||||
kref_init(&item->ci_kref);
|
||||
INIT_LIST_HEAD(&item->ci_entry);
|
||||
}
|
||||
|
||||
/**
|
||||
* config_item_set_name - Set the name of an item
|
||||
* @item: item.
|
||||
* @name: name.
|
||||
*
|
||||
* If strlen(name) >= CONFIGFS_ITEM_NAME_LEN, then use a
|
||||
* dynamically allocated string that @item->ci_name points to.
|
||||
* Otherwise, use the static @item->ci_namebuf array.
|
||||
*/
|
||||
|
||||
int config_item_set_name(struct config_item * item, const char * fmt, ...)
|
||||
{
|
||||
int error = 0;
|
||||
int limit = CONFIGFS_ITEM_NAME_LEN;
|
||||
int need;
|
||||
va_list args;
|
||||
char * name;
|
||||
|
||||
/*
|
||||
* First, try the static array
|
||||
*/
|
||||
va_start(args,fmt);
|
||||
need = vsnprintf(item->ci_namebuf,limit,fmt,args);
|
||||
va_end(args);
|
||||
if (need < limit)
|
||||
name = item->ci_namebuf;
|
||||
else {
|
||||
/*
|
||||
* Need more space? Allocate it and try again
|
||||
*/
|
||||
limit = need + 1;
|
||||
name = kmalloc(limit,GFP_KERNEL);
|
||||
if (!name) {
|
||||
error = -ENOMEM;
|
||||
goto Done;
|
||||
}
|
||||
va_start(args,fmt);
|
||||
need = vsnprintf(name,limit,fmt,args);
|
||||
va_end(args);
|
||||
|
||||
/* Still? Give up. */
|
||||
if (need >= limit) {
|
||||
kfree(name);
|
||||
error = -EFAULT;
|
||||
goto Done;
|
||||
}
|
||||
}
|
||||
|
||||
/* Free the old name, if necessary. */
|
||||
if (item->ci_name && item->ci_name != item->ci_namebuf)
|
||||
kfree(item->ci_name);
|
||||
|
||||
/* Now, set the new name */
|
||||
item->ci_name = name;
|
||||
Done:
|
||||
return error;
|
||||
}
|
||||
|
||||
EXPORT_SYMBOL(config_item_set_name);
|
||||
|
||||
void config_item_init_type_name(struct config_item *item,
|
||||
const char *name,
|
||||
struct config_item_type *type)
|
||||
{
|
||||
config_item_set_name(item, name);
|
||||
item->ci_type = type;
|
||||
config_item_init(item);
|
||||
}
|
||||
EXPORT_SYMBOL(config_item_init_type_name);
|
||||
|
||||
void config_group_init_type_name(struct config_group *group, const char *name,
|
||||
struct config_item_type *type)
|
||||
{
|
||||
config_item_set_name(&group->cg_item, name);
|
||||
group->cg_item.ci_type = type;
|
||||
config_group_init(group);
|
||||
}
|
||||
EXPORT_SYMBOL(config_group_init_type_name);
|
||||
|
||||
struct config_item * config_item_get(struct config_item * item)
|
||||
{
|
||||
if (item)
|
||||
kref_get(&item->ci_kref);
|
||||
return item;
|
||||
}
|
||||
|
||||
/**
|
||||
* config_item_cleanup - free config_item resources.
|
||||
* @item: item.
|
||||
*/
|
||||
|
||||
void config_item_cleanup(struct config_item * item)
|
||||
{
|
||||
struct config_item_type * t = item->ci_type;
|
||||
struct config_group * s = item->ci_group;
|
||||
struct config_item * parent = item->ci_parent;
|
||||
|
||||
pr_debug("config_item %s: cleaning up\n",config_item_name(item));
|
||||
if (item->ci_name != item->ci_namebuf)
|
||||
kfree(item->ci_name);
|
||||
item->ci_name = NULL;
|
||||
if (t && t->ct_item_ops && t->ct_item_ops->release)
|
||||
t->ct_item_ops->release(item);
|
||||
if (s)
|
||||
config_group_put(s);
|
||||
if (parent)
|
||||
config_item_put(parent);
|
||||
}
|
||||
|
||||
static void config_item_release(struct kref *kref)
|
||||
{
|
||||
config_item_cleanup(container_of(kref, struct config_item, ci_kref));
|
||||
}
|
||||
|
||||
/**
|
||||
* config_item_put - decrement refcount for item.
|
||||
* @item: item.
|
||||
*
|
||||
* Decrement the refcount, and if 0, call config_item_cleanup().
|
||||
*/
|
||||
void config_item_put(struct config_item * item)
|
||||
{
|
||||
if (item)
|
||||
kref_put(&item->ci_kref, config_item_release);
|
||||
}
|
||||
|
||||
|
||||
/**
|
||||
* config_group_init - initialize a group for use
|
||||
* @k: group
|
||||
*/
|
||||
|
||||
void config_group_init(struct config_group *group)
|
||||
{
|
||||
config_item_init(&group->cg_item);
|
||||
INIT_LIST_HEAD(&group->cg_children);
|
||||
}
|
||||
|
||||
|
||||
/**
|
||||
* config_group_find_obj - search for item in group.
|
||||
* @group: group we're looking in.
|
||||
* @name: item's name.
|
||||
*
|
||||
* Lock group via @group->cg_subsys, and iterate over @group->cg_list,
|
||||
* looking for a matching config_item. If matching item is found
|
||||
* take a reference and return the item.
|
||||
*/
|
||||
|
||||
struct config_item * config_group_find_obj(struct config_group * group, const char * name)
|
||||
{
|
||||
struct list_head * entry;
|
||||
struct config_item * ret = NULL;
|
||||
|
||||
/* XXX LOCKING! */
|
||||
list_for_each(entry,&group->cg_children) {
|
||||
struct config_item * item = to_item(entry);
|
||||
if (config_item_name(item) &&
|
||||
!strcmp(config_item_name(item), name)) {
|
||||
ret = config_item_get(item);
|
||||
break;
|
||||
}
|
||||
}
|
||||
return ret;
|
||||
}
|
||||
|
||||
|
||||
EXPORT_SYMBOL(config_item_init);
|
||||
EXPORT_SYMBOL(config_group_init);
|
||||
EXPORT_SYMBOL(config_item_get);
|
||||
EXPORT_SYMBOL(config_item_put);
|
||||
|
||||
159
fs/configfs/mount.c
Normal file
159
fs/configfs/mount.c
Normal file
@ -0,0 +1,159 @@
|
||||
/* -*- mode: c; c-basic-offset: 8; -*-
|
||||
* vim: noexpandtab sw=8 ts=8 sts=0:
|
||||
*
|
||||
* mount.c - operations for initializing and mounting configfs.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public
|
||||
* License as published by the Free Software Foundation; either
|
||||
* version 2 of the License, or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
* General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public
|
||||
* License along with this program; if not, write to the
|
||||
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
||||
* Boston, MA 021110-1307, USA.
|
||||
*
|
||||
* Based on sysfs:
|
||||
* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
|
||||
*
|
||||
* configfs Copyright (C) 2005 Oracle. All rights reserved.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/mount.h>
|
||||
#include <linux/pagemap.h>
|
||||
#include <linux/init.h>
|
||||
|
||||
#include <linux/configfs.h>
|
||||
#include "configfs_internal.h"
|
||||
|
||||
/* Random magic number */
|
||||
#define CONFIGFS_MAGIC 0x62656570
|
||||
|
||||
struct vfsmount * configfs_mount = NULL;
|
||||
struct super_block * configfs_sb = NULL;
|
||||
static int configfs_mnt_count = 0;
|
||||
|
||||
static struct super_operations configfs_ops = {
|
||||
.statfs = simple_statfs,
|
||||
.drop_inode = generic_delete_inode,
|
||||
};
|
||||
|
||||
static struct config_group configfs_root_group = {
|
||||
.cg_item = {
|
||||
.ci_namebuf = "root",
|
||||
.ci_name = configfs_root_group.cg_item.ci_namebuf,
|
||||
},
|
||||
};
|
||||
|
||||
int configfs_is_root(struct config_item *item)
|
||||
{
|
||||
return item == &configfs_root_group.cg_item;
|
||||
}
|
||||
|
||||
static struct configfs_dirent configfs_root = {
|
||||
.s_sibling = LIST_HEAD_INIT(configfs_root.s_sibling),
|
||||
.s_children = LIST_HEAD_INIT(configfs_root.s_children),
|
||||
.s_element = &configfs_root_group.cg_item,
|
||||
.s_type = CONFIGFS_ROOT,
|
||||
};
|
||||
|
||||
static int configfs_fill_super(struct super_block *sb, void *data, int silent)
|
||||
{
|
||||
struct inode *inode;
|
||||
struct dentry *root;
|
||||
|
||||
sb->s_blocksize = PAGE_CACHE_SIZE;
|
||||
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
|
||||
sb->s_magic = CONFIGFS_MAGIC;
|
||||
sb->s_op = &configfs_ops;
|
||||
configfs_sb = sb;
|
||||
|
||||
inode = configfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
|
||||
if (inode) {
|
||||
inode->i_op = &configfs_dir_inode_operations;
|
||||
inode->i_fop = &configfs_dir_operations;
|
||||
/* directory inodes start off with i_nlink == 2 (for "." entry) */
|
||||
inode->i_nlink++;
|
||||
} else {
|
||||
pr_debug("configfs: could not get root inode\n");
|
||||
return -ENOMEM;
|
||||
}
|
||||
|
||||
root = d_alloc_root(inode);
|
||||
if (!root) {
|
||||
pr_debug("%s: could not get root dentry!\n",__FUNCTION__);
|
||||
iput(inode);
|
||||
return -ENOMEM;
|
||||
}
|
||||
config_group_init(&configfs_root_group);
|
||||
configfs_root_group.cg_item.ci_dentry = root;
|
||||
root->d_fsdata = &configfs_root;
|
||||
sb->s_root = root;
|
||||
return 0;
|
||||
}
|
||||
|
||||
static struct super_block *configfs_get_sb(struct file_system_type *fs_type,
|
||||
int flags, const char *dev_name, void *data)
|
||||
{
|
||||
return get_sb_single(fs_type, flags, data, configfs_fill_super);
|
||||
}
|
||||
|
||||
static struct file_system_type configfs_fs_type = {
|
||||
.owner = THIS_MODULE,
|
||||
.name = "configfs",
|
||||
.get_sb = configfs_get_sb,
|
||||
.kill_sb = kill_litter_super,
|
||||
};
|
||||
|
||||
int configfs_pin_fs(void)
|
||||
{
|
||||
return simple_pin_fs("configfs", &configfs_mount,
|
||||
&configfs_mnt_count);
|
||||
}
|
||||
|
||||
void configfs_release_fs(void)
|
||||
{
|
||||
simple_release_fs(&configfs_mount, &configfs_mnt_count);
|
||||
}
|
||||
|
||||
|
||||
static decl_subsys(config, NULL, NULL);
|
||||
|
||||
static int __init configfs_init(void)
|
||||
{
|
||||
int err;
|
||||
|
||||
kset_set_kset_s(&config_subsys, kernel_subsys);
|
||||
err = subsystem_register(&config_subsys);
|
||||
if (err)
|
||||
return err;
|
||||
|
||||
err = register_filesystem(&configfs_fs_type);
|
||||
if (err) {
|
||||
printk(KERN_ERR "configfs: Unable to register filesystem!\n");
|
||||
subsystem_unregister(&config_subsys);
|
||||
}
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
static void __exit configfs_exit(void)
|
||||
{
|
||||
unregister_filesystem(&configfs_fs_type);
|
||||
subsystem_unregister(&config_subsys);
|
||||
}
|
||||
|
||||
MODULE_AUTHOR("Oracle");
|
||||
MODULE_LICENSE("GPL");
|
||||
MODULE_VERSION("0.0.1");
|
||||
MODULE_DESCRIPTION("Simple RAM filesystem for user driven kernel subsystem configuration.");
|
||||
|
||||
module_init(configfs_init);
|
||||
module_exit(configfs_exit);
|
||||
281
fs/configfs/symlink.c
Normal file
281
fs/configfs/symlink.c
Normal file
@ -0,0 +1,281 @@
|
||||
/* -*- mode: c; c-basic-offset: 8; -*-
|
||||
* vim: noexpandtab sw=8 ts=8 sts=0:
|
||||
*
|
||||
* symlink.c - operations for configfs symlinks.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public
|
||||
* License as published by the Free Software Foundation; either
|
||||
* version 2 of the License, or (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
* General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public
|
||||
* License along with this program; if not, write to the
|
||||
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
||||
* Boston, MA 021110-1307, USA.
|
||||
*
|
||||
* Based on sysfs:
|
||||
* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
|
||||
*
|
||||
* configfs Copyright (C) 2005 Oracle. All rights reserved.
|
||||
*/
|
||||
|
||||
#include <linux/fs.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/namei.h>
|
||||
|
||||
#include <linux/configfs.h>
|
||||
#include "configfs_internal.h"
|
||||
|
||||
static int item_depth(struct config_item * item)
|
||||
{
|
||||
struct config_item * p = item;
|
||||
int depth = 0;
|
||||
do { depth++; } while ((p = p->ci_parent) && !configfs_is_root(p));
|
||||
return depth;
|
||||
}
|
||||
|
||||
static int item_path_length(struct config_item * item)
|
||||
{
|
||||
struct config_item * p = item;
|
||||
int length = 1;
|
||||
do {
|
||||
length += strlen(config_item_name(p)) + 1;
|
||||
p = p->ci_parent;
|
||||
} while (p && !configfs_is_root(p));
|
||||
return length;
|
||||
}
|
||||
|
||||
static void fill_item_path(struct config_item * item, char * buffer, int length)
|
||||
{
|
||||
struct config_item * p;
|
||||
|
||||
--length;
|
||||
for (p = item; p && !configfs_is_root(p); p = p->ci_parent) {
|
||||
int cur = strlen(config_item_name(p));
|
||||
|
||||
/* back up enough to print this bus id with '/' */
|
||||
length -= cur;
|
||||
strncpy(buffer + length,config_item_name(p),cur);
|
||||
*(buffer + --length) = '/';
|
||||
}
|
||||
}
|
||||
|
||||
static int create_link(struct config_item *parent_item,
|
||||
struct config_item *item,
|
||||
struct dentry *dentry)
|
||||
{
|
||||
struct configfs_dirent *target_sd = item->ci_dentry->d_fsdata;
|
||||
struct configfs_symlink *sl;
|
||||
int ret;
|
||||
|
||||
ret = -ENOMEM;
|
||||
sl = kmalloc(sizeof(struct configfs_symlink), GFP_KERNEL);
|
||||
if (sl) {
|
||||
sl->sl_target = config_item_get(item);
|
||||
/* FIXME: needs a lock, I'd bet */
|
||||
list_add(&sl->sl_list, &target_sd->s_links);
|
||||
ret = configfs_create_link(sl, parent_item->ci_dentry,
|
||||
dentry);
|
||||
if (ret) {
|
||||
list_del_init(&sl->sl_list);
|
||||
config_item_put(item);
|
||||
kfree(sl);
|
||||
}
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
|
||||
static int get_target(const char *symname, struct nameidata *nd,
|
||||
struct config_item **target)
|
||||
{
|
||||
int ret;
|
||||
|
||||
ret = path_lookup(symname, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, nd);
|
||||
if (!ret) {
|
||||
if (nd->dentry->d_sb == configfs_sb) {
|
||||
*target = configfs_get_config_item(nd->dentry);
|
||||
if (!*target) {
|
||||
ret = -ENOENT;
|
||||
path_release(nd);
|
||||
}
|
||||
} else
|
||||
ret = -EPERM;
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
|
||||
int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
|
||||
{
|
||||
int ret;
|
||||
struct nameidata nd;
|
||||
struct config_item *parent_item;
|
||||
struct config_item *target_item;
|
||||
struct config_item_type *type;
|
||||
|
||||
ret = -EPERM; /* What lack-of-symlink returns */
|
||||
if (dentry->d_parent == configfs_sb->s_root)
|
||||
goto out;
|
||||
|
||||
parent_item = configfs_get_config_item(dentry->d_parent);
|
||||
type = parent_item->ci_type;
|
||||
|
||||
if (!type || !type->ct_item_ops ||
|
||||
!type->ct_item_ops->allow_link)
|
||||
goto out_put;
|
||||
|
||||
ret = get_target(symname, &nd, &target_item);
|
||||
if (ret)
|
||||
goto out_put;
|
||||
|
||||
ret = type->ct_item_ops->allow_link(parent_item, target_item);
|
||||
if (!ret)
|
||||
ret = create_link(parent_item, target_item, dentry);
|
||||
|
||||
config_item_put(target_item);
|
||||
path_release(&nd);
|
||||
|
||||
out_put:
|
||||
config_item_put(parent_item);
|
||||
|
||||
out:
|
||||
return ret;
|
||||
}
|
||||
|
||||
int configfs_unlink(struct inode *dir, struct dentry *dentry)
|
||||
{
|
||||
struct configfs_dirent *sd = dentry->d_fsdata;
|
||||
struct configfs_symlink *sl;
|
||||
struct config_item *parent_item;
|
||||
struct config_item_type *type;
|
||||
int ret;
|
||||
|
||||
ret = -EPERM; /* What lack-of-symlink returns */
|
||||
if (!(sd->s_type & CONFIGFS_ITEM_LINK))
|
||||
goto out;
|
||||
|
||||
if (dentry->d_parent == configfs_sb->s_root)
|
||||
BUG();
|
||||
|
||||
sl = sd->s_element;
|
||||
|
||||
parent_item = configfs_get_config_item(dentry->d_parent);
|
||||
type = parent_item->ci_type;
|
||||
|
||||
list_del_init(&sd->s_sibling);
|
||||
configfs_drop_dentry(sd, dentry->d_parent);
|
||||
dput(dentry);
|
||||
configfs_put(sd);
|
||||
|
||||
/*
|
||||
* drop_link() must be called before
|
||||
* list_del_init(&sl->sl_list), so that the order of
|
||||
* drop_link(this, target) and drop_item(target) is preserved.
|
||||
*/
|
||||
if (type && type->ct_item_ops &&
|
||||
type->ct_item_ops->drop_link)
|
||||
type->ct_item_ops->drop_link(parent_item,
|
||||
sl->sl_target);
|
||||
|
||||
/* FIXME: Needs lock */
|
||||
list_del_init(&sl->sl_list);
|
||||
|
||||
/* Put reference from create_link() */
|
||||
config_item_put(sl->sl_target);
|
||||
kfree(sl);
|
||||
|
||||
config_item_put(parent_item);
|
||||
|
||||
ret = 0;
|
||||
|
||||
out:
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int configfs_get_target_path(struct config_item * item, struct config_item * target,
|
||||
char *path)
|
||||
{
|
||||
char * s;
|
||||
int depth, size;
|
||||
|
||||
depth = item_depth(item);
|
||||
size = item_path_length(target) + depth * 3 - 1;
|
||||
if (size > PATH_MAX)
|
||||
return -ENAMETOOLONG;
|
||||
|
||||
pr_debug("%s: depth = %d, size = %d\n", __FUNCTION__, depth, size);
|
||||
|
||||
for (s = path; depth--; s += 3)
|
||||
strcpy(s,"../");
|
||||
|
||||
fill_item_path(target, path, size);
|
||||
pr_debug("%s: path = '%s'\n", __FUNCTION__, path);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int configfs_getlink(struct dentry *dentry, char * path)
|
||||
{
|
||||
struct config_item *item, *target_item;
|
||||
int error = 0;
|
||||
|
||||
item = configfs_get_config_item(dentry->d_parent);
|
||||
if (!item)
|
||||
return -EINVAL;
|
||||
|
||||
target_item = configfs_get_config_item(dentry);
|
||||
if (!target_item) {
|
||||
config_item_put(item);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
down_read(&configfs_rename_sem);
|
||||
error = configfs_get_target_path(item, target_item, path);
|
||||
up_read(&configfs_rename_sem);
|
||||
|
||||
config_item_put(item);
|
||||
config_item_put(target_item);
|
||||
return error;
|
||||
|
||||
}
|
||||
|
||||
static void *configfs_follow_link(struct dentry *dentry, struct nameidata *nd)
|
||||
{
|
||||
int error = -ENOMEM;
|
||||
unsigned long page = get_zeroed_page(GFP_KERNEL);
|
||||
|
||||
if (page) {
|
||||
error = configfs_getlink(dentry, (char *)page);
|
||||
if (!error) {
|
||||
nd_set_link(nd, (char *)page);
|
||||
return (void *)page;
|
||||
}
|
||||
}
|
||||
|
||||
nd_set_link(nd, ERR_PTR(error));
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static void configfs_put_link(struct dentry *dentry, struct nameidata *nd,
|
||||
void *cookie)
|
||||
{
|
||||
if (cookie) {
|
||||
unsigned long page = (unsigned long)cookie;
|
||||
free_page(page);
|
||||
}
|
||||
}
|
||||
|
||||
struct inode_operations configfs_symlink_inode_operations = {
|
||||
.follow_link = configfs_follow_link,
|
||||
.readlink = generic_readlink,
|
||||
.put_link = configfs_put_link,
|
||||
};
|
||||
|
||||
Reference in New Issue
Block a user