--- /dev/null
+/*
+ * fs/kernfs/inode.c - kernfs inode implementation
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/pagemap.h>
+#include <linux/backing-dev.h>
+#include <linux/capability.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/xattr.h>
+#include <linux/security.h>
+
+#include "kernfs-internal.h"
+
+static const struct address_space_operations kernfs_aops = {
+ .readpage = simple_readpage,
+ .write_begin = simple_write_begin,
+ .write_end = simple_write_end,
+};
+
+static const struct inode_operations kernfs_iops = {
+ .permission = kernfs_iop_permission,
+ .setattr = kernfs_iop_setattr,
+ .getattr = kernfs_iop_getattr,
+ .setxattr = kernfs_iop_setxattr,
+ .removexattr = kernfs_iop_removexattr,
+ .getxattr = kernfs_iop_getxattr,
+ .listxattr = kernfs_iop_listxattr,
+};
+
+static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
+{
+ static DEFINE_MUTEX(iattr_mutex);
+ struct kernfs_iattrs *ret;
+ struct iattr *iattrs;
+
+ mutex_lock(&iattr_mutex);
+
+ if (kn->iattr)
+ goto out_unlock;
+
+ kn->iattr = kzalloc(sizeof(struct kernfs_iattrs), GFP_KERNEL);
+ if (!kn->iattr)
+ goto out_unlock;
+ iattrs = &kn->iattr->ia_iattr;
+
+ /* assign default attributes */
+ iattrs->ia_mode = kn->mode;
+ iattrs->ia_uid = GLOBAL_ROOT_UID;
+ iattrs->ia_gid = GLOBAL_ROOT_GID;
+ iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME;
+
+ simple_xattrs_init(&kn->iattr->xattrs);
+out_unlock:
+ ret = kn->iattr;
+ mutex_unlock(&iattr_mutex);
+ return ret;
+}
+
+static int __kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
+{
+ struct kernfs_iattrs *attrs;
+ struct iattr *iattrs;
+ unsigned int ia_valid = iattr->ia_valid;
+
+ attrs = kernfs_iattrs(kn);
+ if (!attrs)
+ return -ENOMEM;
+
+ iattrs = &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 = kn->mode = mode;
+ }
+ return 0;
+}
+
+/**
+ * kernfs_setattr - set iattr on a node
+ * @kn: target node
+ * @iattr: iattr to set
+ *
+ * Returns 0 on success, -errno on failure.
+ */
+int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
+{
+ int ret;
+
+ mutex_lock(&kernfs_mutex);
+ ret = __kernfs_setattr(kn, iattr);
+ mutex_unlock(&kernfs_mutex);
+ return ret;
+}
+
+int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+ struct inode *inode = d_inode(dentry);
+ struct kernfs_node *kn = dentry->d_fsdata;
+ int error;
+
+ if (!kn)
+ return -EINVAL;
+
+ mutex_lock(&kernfs_mutex);
+ error = inode_change_ok(inode, iattr);
+ if (error)
+ goto out;
+
+ error = __kernfs_setattr(kn, iattr);
+ if (error)
+ goto out;
+
+ /* this ignores size changes */
+ setattr_copy(inode, iattr);
+
+out:
+ mutex_unlock(&kernfs_mutex);
+ return error;
+}
+
+static int kernfs_node_setsecdata(struct kernfs_node *kn, void **secdata,
+ u32 *secdata_len)
+{
+ struct kernfs_iattrs *attrs;
+ void *old_secdata;
+ size_t old_secdata_len;
+
+ attrs = kernfs_iattrs(kn);
+ if (!attrs)
+ return -ENOMEM;
+
+ old_secdata = attrs->ia_secdata;
+ old_secdata_len = attrs->ia_secdata_len;
+
+ attrs->ia_secdata = *secdata;
+ attrs->ia_secdata_len = *secdata_len;
+
+ *secdata = old_secdata;
+ *secdata_len = old_secdata_len;
+ return 0;
+}
+
+int kernfs_iop_setxattr(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags)
+{
+ struct kernfs_node *kn = dentry->d_fsdata;
+ struct kernfs_iattrs *attrs;
+ void *secdata;
+ int error;
+ u32 secdata_len = 0;
+
+ attrs = kernfs_iattrs(kn);
+ if (!attrs)
+ return -ENOMEM;
+
+ if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) {
+ const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
+ error = security_inode_setsecurity(d_inode(dentry), suffix,
+ value, size, flags);
+ if (error)
+ return error;
+ error = security_inode_getsecctx(d_inode(dentry),
+ &secdata, &secdata_len);
+ if (error)
+ return error;
+
+ mutex_lock(&kernfs_mutex);
+ error = kernfs_node_setsecdata(kn, &secdata, &secdata_len);
+ mutex_unlock(&kernfs_mutex);
+
+ if (secdata)
+ security_release_secctx(secdata, secdata_len);
+ return error;
+ } else if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
+ return simple_xattr_set(&attrs->xattrs, name, value, size,
+ flags);
+ }
+
+ return -EINVAL;
+}
+
+int kernfs_iop_removexattr(struct dentry *dentry, const char *name)
+{
+ struct kernfs_node *kn = dentry->d_fsdata;
+ struct kernfs_iattrs *attrs;
+
+ attrs = kernfs_iattrs(kn);
+ if (!attrs)
+ return -ENOMEM;
+
+ return simple_xattr_remove(&attrs->xattrs, name);
+}
+
+ssize_t kernfs_iop_getxattr(struct dentry *dentry, const char *name, void *buf,
+ size_t size)
+{
+ struct kernfs_node *kn = dentry->d_fsdata;
+ struct kernfs_iattrs *attrs;
+
+ attrs = kernfs_iattrs(kn);
+ if (!attrs)
+ return -ENOMEM;
+
+ return simple_xattr_get(&attrs->xattrs, name, buf, size);
+}
+
+ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
+{
+ struct kernfs_node *kn = dentry->d_fsdata;
+ struct kernfs_iattrs *attrs;
+
+ attrs = kernfs_iattrs(kn);
+ if (!attrs)
+ return -ENOMEM;
+
+ return simple_xattr_list(&attrs->xattrs, buf, size);
+}
+
+static inline void set_default_inode_attr(struct inode *inode, umode_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 void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)
+{
+ struct kernfs_iattrs *attrs = kn->iattr;
+
+ inode->i_mode = kn->mode;
+ if (attrs) {
+ /*
+ * kernfs_node has non-default attributes get them from
+ * persistent copy in kernfs_node.
+ */
+ set_inode_attr(inode, &attrs->ia_iattr);
+ security_inode_notifysecctx(inode, attrs->ia_secdata,
+ attrs->ia_secdata_len);
+ }
+
+ if (kernfs_type(kn) == KERNFS_DIR)
+ set_nlink(inode, kn->dir.subdirs + 2);
+}
+
+int kernfs_iop_getattr(struct vfsmount *mnt, struct dentry *dentry,
+ struct kstat *stat)
+{
+ struct kernfs_node *kn = dentry->d_fsdata;
+ struct inode *inode = d_inode(dentry);
+
+ mutex_lock(&kernfs_mutex);
+ kernfs_refresh_inode(kn, inode);
+ mutex_unlock(&kernfs_mutex);
+
+ generic_fillattr(inode, stat);
+ return 0;
+}
+
+static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode)
+{
+ kernfs_get(kn);
+ inode->i_private = kn;
+ inode->i_mapping->a_ops = &kernfs_aops;
+ inode->i_op = &kernfs_iops;
+
+ set_default_inode_attr(inode, kn->mode);
+ kernfs_refresh_inode(kn, inode);
+
+ /* initialize inode according to type */
+ switch (kernfs_type(kn)) {
+ case KERNFS_DIR:
+ inode->i_op = &kernfs_dir_iops;
+ inode->i_fop = &kernfs_dir_fops;
+ if (kn->flags & KERNFS_EMPTY_DIR)
+ make_empty_dir_inode(inode);
+ break;
+ case KERNFS_FILE:
+ inode->i_size = kn->attr.size;
+ inode->i_fop = &kernfs_file_fops;
+ break;
+ case KERNFS_LINK:
+ inode->i_op = &kernfs_symlink_iops;
+ break;
+ default:
+ BUG();
+ }
+
+ unlock_new_inode(inode);
+}
+
+/**
+ * kernfs_get_inode - get inode for kernfs_node
+ * @sb: super block
+ * @kn: kernfs_node to allocate inode for
+ *
+ * Get inode for @kn. 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 *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn)
+{
+ struct inode *inode;
+
+ inode = iget_locked(sb, kn->ino);
+ if (inode && (inode->i_state & I_NEW))
+ kernfs_init_inode(kn, inode);
+
+ return inode;
+}
+
+/*
+ * The kernfs_node serves as both an inode and a directory entry for
+ * kernfs. To prevent the kernfs inode numbers from being freed
+ * prematurely we take a reference to kernfs_node from the kernfs inode. A
+ * super_operations.evict_inode() implementation is needed to drop that
+ * reference upon inode destruction.
+ */
+void kernfs_evict_inode(struct inode *inode)
+{
+ struct kernfs_node *kn = inode->i_private;
+
+ truncate_inode_pages_final(&inode->i_data);
+ clear_inode(inode);
+ kernfs_put(kn);
+}
+
+int kernfs_iop_permission(struct inode *inode, int mask)
+{
+ struct kernfs_node *kn;
+
+ if (mask & MAY_NOT_BLOCK)
+ return -ECHILD;
+
+ kn = inode->i_private;
+
+ mutex_lock(&kernfs_mutex);
+ kernfs_refresh_inode(kn, inode);
+ mutex_unlock(&kernfs_mutex);
+
+ return generic_permission(inode, mask);
+}
Code Review / kvmfornfv.git / blobdiff