/*
- * inode.c - basic inode and dentry operations.
+ * fs/sysfs/inode.c - basic sysfs inode and dentry operations
*
- * sysfs is Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
+ *
+ * This file is released under the GPLv2.
*
* Please see Documentation/filesystems/sysfs.txt for more information.
*/
#include <linux/pagemap.h>
#include <linux/namei.h>
#include <linux/backing-dev.h>
+#include <linux/capability.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/xattr.h>
+#include <linux/security.h>
#include "sysfs.h"
extern struct super_block * sysfs_sb;
-static struct address_space_operations sysfs_aops = {
+static const struct address_space_operations sysfs_aops = {
.readpage = simple_readpage,
- .prepare_write = simple_prepare_write,
- .commit_write = simple_commit_write
+ .write_begin = simple_write_begin,
+ .write_end = simple_write_end,
};
static struct backing_dev_info sysfs_backing_dev_info = {
+ .name = "sysfs",
.ra_pages = 0, /* No readahead */
- .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
+};
+
+static const struct inode_operations sysfs_inode_operations ={
+ .permission = sysfs_permission,
+ .setattr = sysfs_setattr,
+ .getattr = sysfs_getattr,
+ .setxattr = sysfs_setxattr,
};
-struct inode * sysfs_new_inode(mode_t mode)
-{
- struct inode * inode = new_inode(sysfs_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 = &sysfs_aops;
- inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
+int __init sysfs_inode_init(void)
+{
+ return bdi_init(&sysfs_backing_dev_info);
+}
+
+static struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd)
+{
+ struct sysfs_inode_attrs *attrs;
+ struct iattr *iattrs;
+
+ attrs = kzalloc(sizeof(struct sysfs_inode_attrs), GFP_KERNEL);
+ if (!attrs)
+ return NULL;
+ iattrs = &attrs->ia_iattr;
+
+ /* assign default attributes */
+ iattrs->ia_mode = sd->s_mode;
+ iattrs->ia_uid = 0;
+ iattrs->ia_gid = 0;
+ iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME;
+
+ return attrs;
+}
+
+int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr)
+{
+ struct sysfs_inode_attrs *sd_attrs;
+ struct iattr *iattrs;
+ unsigned int ia_valid = iattr->ia_valid;
+
+ sd_attrs = sd->s_iattr;
+
+ if (!sd_attrs) {
+ /* setting attributes for the first time, allocate now */
+ sd_attrs = sysfs_init_inode_attrs(sd);
+ if (!sd_attrs)
+ return -ENOMEM;
+ sd->s_iattr = sd_attrs;
}
- return inode;
+ /* attributes were changed at least once in past */
+ iattrs = &sd_attrs->ia_iattr;
+
+ if (ia_valid & ATTR_UID)
+ iattrs->ia_uid = iattr->ia_uid;
+ if (ia_valid & ATTR_GID)
+ iattrs->ia_gid = iattr->ia_gid;
+ if (ia_valid & ATTR_ATIME)
+ iattrs->ia_atime = iattr->ia_atime;
+ if (ia_valid & ATTR_MTIME)
+ iattrs->ia_mtime = iattr->ia_mtime;
+ if (ia_valid & ATTR_CTIME)
+ iattrs->ia_ctime = iattr->ia_ctime;
+ if (ia_valid & ATTR_MODE) {
+ umode_t mode = iattr->ia_mode;
+ iattrs->ia_mode = sd->s_mode = mode;
+ }
+ return 0;
+}
+
+int sysfs_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+ struct inode *inode = dentry->d_inode;
+ struct sysfs_dirent *sd = dentry->d_fsdata;
+ int error;
+
+ if (!sd)
+ return -EINVAL;
+
+ mutex_lock(&sysfs_mutex);
+ error = inode_change_ok(inode, iattr);
+ if (error)
+ goto out;
+
+ iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */
+
+ error = inode_setattr(inode, iattr);
+ if (error)
+ goto out;
+
+ error = sysfs_sd_setattr(sd, iattr);
+out:
+ mutex_unlock(&sysfs_mutex);
+ return error;
+}
+
+static int sysfs_sd_setsecdata(struct sysfs_dirent *sd, void **secdata, u32 *secdata_len)
+{
+ struct sysfs_inode_attrs *iattrs;
+ void *old_secdata;
+ size_t old_secdata_len;
+
+ iattrs = sd->s_iattr;
+ if (!iattrs)
+ iattrs = sysfs_init_inode_attrs(sd);
+ if (!iattrs)
+ return -ENOMEM;
+
+ old_secdata = iattrs->ia_secdata;
+ old_secdata_len = iattrs->ia_secdata_len;
+
+ iattrs->ia_secdata = *secdata;
+ iattrs->ia_secdata_len = *secdata_len;
+
+ *secdata = old_secdata;
+ *secdata_len = old_secdata_len;
+ return 0;
}
-int sysfs_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 = sysfs_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))
- dget(dentry); /* pin only directory dentry in core */
+int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
+ size_t size, int flags)
+{
+ struct sysfs_dirent *sd = dentry->d_fsdata;
+ void *secdata;
+ int error;
+ u32 secdata_len = 0;
+
+ if (!sd)
+ return -EINVAL;
+
+ if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) {
+ const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
+ error = security_inode_setsecurity(dentry->d_inode, suffix,
+ value, size, flags);
+ if (error)
+ goto out;
+ error = security_inode_getsecctx(dentry->d_inode,
+ &secdata, &secdata_len);
+ if (error)
+ goto out;
+
+ mutex_lock(&sysfs_mutex);
+ error = sysfs_sd_setsecdata(sd, &secdata, &secdata_len);
+ mutex_unlock(&sysfs_mutex);
+
+ if (secdata)
+ security_release_secctx(secdata, secdata_len);
} else
- iput(inode);
- Done:
+ return -EINVAL;
+out:
return error;
}
-struct dentry * sysfs_get_dentry(struct dentry * parent, const char * name)
+static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
+{
+ inode->i_mode = mode;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+}
+
+static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
+{
+ inode->i_uid = iattr->ia_uid;
+ inode->i_gid = iattr->ia_gid;
+ inode->i_atime = iattr->ia_atime;
+ inode->i_mtime = iattr->ia_mtime;
+ inode->i_ctime = iattr->ia_ctime;
+}
+
+static int sysfs_count_nlink(struct sysfs_dirent *sd)
{
- struct qstr qstr;
+ struct sysfs_dirent *child;
+ int nr = 0;
- qstr.name = name;
- qstr.len = strlen(name);
- qstr.hash = full_name_hash(name,qstr.len);
- return lookup_hash(&qstr,parent);
+ for (child = sd->s_dir.children; child; child = child->s_sibling)
+ if (sysfs_type(child) == SYSFS_DIR)
+ nr++;
+
+ return nr + 2;
}
-/*
- * Get the name for corresponding element represented by the given sysfs_dirent
- */
-const unsigned char * sysfs_get_name(struct sysfs_dirent *sd)
+static void sysfs_refresh_inode(struct sysfs_dirent *sd, struct inode *inode)
{
- struct attribute * attr;
- struct bin_attribute * bin_attr;
- struct sysfs_symlink * sl;
+ struct sysfs_inode_attrs *iattrs = sd->s_iattr;
- if (!sd || !sd->s_element)
- BUG();
+ inode->i_mode = sd->s_mode;
+ if (iattrs) {
+ /* sysfs_dirent has non-default attributes
+ * get them from persistent copy in sysfs_dirent
+ */
+ set_inode_attr(inode, &iattrs->ia_iattr);
+ security_inode_notifysecctx(inode,
+ iattrs->ia_secdata,
+ iattrs->ia_secdata_len);
+ }
- switch (sd->s_type) {
- case SYSFS_DIR:
- /* Always have a dentry so use that */
- return sd->s_dentry->d_name.name;
+ if (sysfs_type(sd) == SYSFS_DIR)
+ inode->i_nlink = sysfs_count_nlink(sd);
+}
+
+int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
+{
+ struct sysfs_dirent *sd = dentry->d_fsdata;
+ struct inode *inode = dentry->d_inode;
+
+ mutex_lock(&sysfs_mutex);
+ sysfs_refresh_inode(sd, inode);
+ mutex_unlock(&sysfs_mutex);
+
+ generic_fillattr(inode, stat);
+ return 0;
+}
+
+static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
+{
+ struct bin_attribute *bin_attr;
- case SYSFS_KOBJ_ATTR:
- attr = sd->s_element;
- return attr->name;
+ inode->i_private = sysfs_get(sd);
+ inode->i_mapping->a_ops = &sysfs_aops;
+ inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
+ inode->i_op = &sysfs_inode_operations;
- case SYSFS_KOBJ_BIN_ATTR:
- bin_attr = sd->s_element;
- return bin_attr->attr.name;
+ set_default_inode_attr(inode, sd->s_mode);
+ sysfs_refresh_inode(sd, inode);
- case SYSFS_KOBJ_LINK:
- sl = sd->s_element;
- return sl->link_name;
+ /* initialize inode according to type */
+ switch (sysfs_type(sd)) {
+ case SYSFS_DIR:
+ inode->i_op = &sysfs_dir_inode_operations;
+ inode->i_fop = &sysfs_dir_operations;
+ break;
+ case SYSFS_KOBJ_ATTR:
+ inode->i_size = PAGE_SIZE;
+ inode->i_fop = &sysfs_file_operations;
+ break;
+ case SYSFS_KOBJ_BIN_ATTR:
+ bin_attr = sd->s_bin_attr.bin_attr;
+ inode->i_size = bin_attr->size;
+ inode->i_fop = &bin_fops;
+ break;
+ case SYSFS_KOBJ_LINK:
+ inode->i_op = &sysfs_symlink_inode_operations;
+ break;
+ default:
+ BUG();
}
- return NULL;
+
+ unlock_new_inode(inode);
}
+/**
+ * sysfs_get_inode - get inode for sysfs_dirent
+ * @sb: super block
+ * @sd: sysfs_dirent to allocate inode for
+ *
+ * Get inode for @sd. If such inode doesn't exist, a new inode
+ * is allocated and basics are initialized. New inode is
+ * returned locked.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep).
+ *
+ * RETURNS:
+ * Pointer to allocated inode on success, NULL on failure.
+ */
+struct inode * sysfs_get_inode(struct super_block *sb, struct sysfs_dirent *sd)
+{
+ struct inode *inode;
+
+ inode = iget_locked(sb, sd->s_ino);
+ if (inode && (inode->i_state & I_NEW))
+ sysfs_init_inode(sd, inode);
+
+ return inode;
+}
/*
- * Unhashes the dentry corresponding to given sysfs_dirent
- * Called with parent inode's i_sem held.
+ * The sysfs_dirent serves as both an inode and a directory entry for sysfs.
+ * To prevent the sysfs inode numbers from being freed prematurely we take a
+ * reference to sysfs_dirent from the sysfs inode. A
+ * super_operations.delete_inode() implementation is needed to drop that
+ * reference upon inode destruction.
*/
-void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent)
-{
- struct dentry * dentry = sd->s_dentry;
-
- if (dentry) {
- spin_lock(&dcache_lock);
- spin_lock(&dentry->d_lock);
- if (!(d_unhashed(dentry) && dentry->d_inode)) {
- dget_locked(dentry);
- __d_drop(dentry);
- spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
- simple_unlink(parent->d_inode, dentry);
- } else {
- spin_unlock(&dentry->d_lock);
- spin_unlock(&dcache_lock);
- }
- }
+void sysfs_delete_inode(struct inode *inode)
+{
+ struct sysfs_dirent *sd = inode->i_private;
+
+ truncate_inode_pages(&inode->i_data, 0);
+ clear_inode(inode);
+ sysfs_put(sd);
}
-void sysfs_hash_and_remove(struct dentry * dir, const char * name)
+int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)
{
- struct sysfs_dirent * sd;
- struct sysfs_dirent * parent_sd = dir->d_fsdata;
+ struct sysfs_addrm_cxt acxt;
+ struct sysfs_dirent *sd;
- down(&dir->d_inode->i_sem);
- list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
- if (!sd->s_element)
- continue;
- if (!strcmp(sysfs_get_name(sd), name)) {
- list_del_init(&sd->s_sibling);
- sysfs_drop_dentry(sd, dir);
- sysfs_put(sd);
- break;
- }
- }
- up(&dir->d_inode->i_sem);
+ if (!dir_sd)
+ return -ENOENT;
+
+ sysfs_addrm_start(&acxt, dir_sd);
+
+ sd = sysfs_find_dirent(dir_sd, name);
+ if (sd)
+ sysfs_remove_one(&acxt, sd);
+
+ sysfs_addrm_finish(&acxt);
+
+ if (sd)
+ return 0;
+ else
+ return -ENOENT;
}
+int sysfs_permission(struct inode *inode, int mask)
+{
+ struct sysfs_dirent *sd = inode->i_private;
+ mutex_lock(&sysfs_mutex);
+ sysfs_refresh_inode(sd, inode);
+ mutex_unlock(&sysfs_mutex);
+
+ return generic_permission(inode, mask, NULL);
+}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff