/* -*- 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/capability.h> #include <linux/configfs.h> #include "configfs_internal.h" extern struct super_block * configfs_sb; static const 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, }; static struct inode_operations configfs_inode_operations ={ .setattr = configfs_setattr, }; int configfs_setattr(struct dentry * dentry, struct iattr * iattr) { struct inode * inode = dentry->d_inode; struct configfs_dirent * sd = dentry->d_fsdata; struct iattr * sd_iattr; unsigned int ia_valid = iattr->ia_valid; int error; if (!sd) return -EINVAL; sd_iattr = sd->s_iattr; error = inode_change_ok(inode, iattr); if (error) return error; error = inode_setattr(inode, iattr); if (error) return error; if (!sd_iattr) { /* setting attributes for the first time, allocate now */ sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); if (!sd_iattr) return -ENOMEM; /* assign default attributes */ sd_iattr->ia_mode = sd->s_mode; sd_iattr->ia_uid = 0; sd_iattr->ia_gid = 0; sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME; sd->s_iattr = sd_iattr; } /* attributes were changed atleast once in past */ if (ia_valid & ATTR_UID) sd_iattr->ia_uid = iattr->ia_uid; if (ia_valid & ATTR_GID) sd_iattr->ia_gid = iattr->ia_gid; if (ia_valid & ATTR_ATIME) sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime, inode->i_sb->s_time_gran); if (ia_valid & ATTR_MTIME) sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime, inode->i_sb->s_time_gran); if (ia_valid & ATTR_CTIME) sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime, inode->i_sb->s_time_gran); if (ia_valid & ATTR_MODE) { umode_t mode = iattr->ia_mode; if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) mode &= ~S_ISGID; sd_iattr->ia_mode = sd->s_mode = mode; } return error; } static inline void set_default_inode_attr(struct inode * inode, mode_t mode) { inode->i_mode = mode; inode->i_uid = 0; inode->i_gid = 0; 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_mode = iattr->ia_mode; 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; } struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent * sd) { struct inode * inode = new_inode(configfs_sb); if (inode) { inode->i_blocks = 0; inode->i_mapping->a_ops = &configfs_aops; inode->i_mapping->backing_dev_info = &configfs_backing_dev_info; inode->i_op = &configfs_inode_operations; if (sd->s_iattr) { /* sysfs_dirent has non-default attributes * get them for the new inode from persistent copy * in sysfs_dirent */ set_inode_attr(inode, sd->s_iattr); } else set_default_inode_attr(inode, mode); } 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) { struct configfs_dirent *sd = dentry->d_fsdata; if ((inode = configfs_new_inode(mode, sd))) { 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 configfs_attribute *attr; BUG_ON(!sd || !sd->s_element); /* 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->ca_name; } return NULL; } /* * Unhashes the dentry corresponding to given configfs_dirent * Called with parent inode's i_mutex held. */ void configfs_drop_dentry(struct configfs_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 configfs_hash_and_remove(struct dentry * dir, const char * name) { struct configfs_dirent * sd; struct configfs_dirent * parent_sd = dir->d_fsdata; if (dir->d_inode == NULL) /* no inode means this hasn't been made visible yet */ return; mutex_lock(&dir->d_inode->i_mutex); 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; } } mutex_unlock(&dir->d_inode->i_mutex); }