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296 lines
7.6 KiB
296 lines
7.6 KiB
/* -*- 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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* inode.c - basic inode and dentry operations. |
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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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* Please see Documentation/filesystems/configfs/configfs.txt for more |
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* information. |
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*/ |
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#undef DEBUG |
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#include <linux/pagemap.h> |
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#include <linux/namei.h> |
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#include <linux/backing-dev.h> |
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#include <linux/capability.h> |
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#include <linux/sched.h> |
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#include <linux/lockdep.h> |
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#include <linux/slab.h> |
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#include <linux/configfs.h> |
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#include "configfs_internal.h" |
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#ifdef CONFIG_LOCKDEP |
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static struct lock_class_key default_group_class[MAX_LOCK_DEPTH]; |
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#endif |
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static const struct address_space_operations configfs_aops = { |
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.readpage = simple_readpage, |
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.write_begin = simple_write_begin, |
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.write_end = simple_write_end, |
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}; |
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static struct backing_dev_info configfs_backing_dev_info = { |
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.name = "configfs", |
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.ra_pages = 0, /* No readahead */ |
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.capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, |
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}; |
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static const struct inode_operations configfs_inode_operations ={ |
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.setattr = configfs_setattr, |
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}; |
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int configfs_setattr(struct dentry * dentry, struct iattr * iattr) |
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{ |
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struct inode * inode = dentry->d_inode; |
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struct configfs_dirent * sd = dentry->d_fsdata; |
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struct iattr * sd_iattr; |
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unsigned int ia_valid = iattr->ia_valid; |
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int error; |
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if (!sd) |
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return -EINVAL; |
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sd_iattr = sd->s_iattr; |
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if (!sd_iattr) { |
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/* setting attributes for the first time, allocate now */ |
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sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); |
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if (!sd_iattr) |
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return -ENOMEM; |
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/* assign default attributes */ |
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sd_iattr->ia_mode = sd->s_mode; |
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sd_iattr->ia_uid = GLOBAL_ROOT_UID; |
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sd_iattr->ia_gid = GLOBAL_ROOT_GID; |
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sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME; |
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sd->s_iattr = sd_iattr; |
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} |
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/* attributes were changed atleast once in past */ |
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error = simple_setattr(dentry, iattr); |
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if (error) |
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return error; |
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if (ia_valid & ATTR_UID) |
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sd_iattr->ia_uid = iattr->ia_uid; |
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if (ia_valid & ATTR_GID) |
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sd_iattr->ia_gid = iattr->ia_gid; |
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if (ia_valid & ATTR_ATIME) |
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sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime, |
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inode->i_sb->s_time_gran); |
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if (ia_valid & ATTR_MTIME) |
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sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime, |
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inode->i_sb->s_time_gran); |
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if (ia_valid & ATTR_CTIME) |
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sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime, |
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inode->i_sb->s_time_gran); |
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if (ia_valid & ATTR_MODE) { |
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umode_t mode = iattr->ia_mode; |
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if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) |
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mode &= ~S_ISGID; |
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sd_iattr->ia_mode = sd->s_mode = mode; |
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} |
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return error; |
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} |
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static inline void set_default_inode_attr(struct inode * inode, umode_t mode) |
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{ |
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inode->i_mode = mode; |
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
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} |
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static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) |
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{ |
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inode->i_mode = iattr->ia_mode; |
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inode->i_uid = iattr->ia_uid; |
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inode->i_gid = iattr->ia_gid; |
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inode->i_atime = iattr->ia_atime; |
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inode->i_mtime = iattr->ia_mtime; |
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inode->i_ctime = iattr->ia_ctime; |
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} |
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struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd, |
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struct super_block *s) |
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{ |
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struct inode * inode = new_inode(s); |
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if (inode) { |
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inode->i_ino = get_next_ino(); |
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inode->i_mapping->a_ops = &configfs_aops; |
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inode->i_mapping->backing_dev_info = &configfs_backing_dev_info; |
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inode->i_op = &configfs_inode_operations; |
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if (sd->s_iattr) { |
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/* sysfs_dirent has non-default attributes |
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* get them for the new inode from persistent copy |
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* in sysfs_dirent |
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*/ |
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set_inode_attr(inode, sd->s_iattr); |
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} else |
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set_default_inode_attr(inode, mode); |
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} |
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return inode; |
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} |
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#ifdef CONFIG_LOCKDEP |
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static void configfs_set_inode_lock_class(struct configfs_dirent *sd, |
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struct inode *inode) |
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{ |
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int depth = sd->s_depth; |
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if (depth > 0) { |
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if (depth <= ARRAY_SIZE(default_group_class)) { |
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lockdep_set_class(&inode->i_mutex, |
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&default_group_class[depth - 1]); |
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} else { |
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/* |
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* In practice the maximum level of locking depth is |
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* already reached. Just inform about possible reasons. |
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*/ |
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printk(KERN_INFO "configfs: Too many levels of inodes" |
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" for the locking correctness validator.\n"); |
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printk(KERN_INFO "Spurious warnings may appear.\n"); |
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} |
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} |
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} |
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#else /* CONFIG_LOCKDEP */ |
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static void configfs_set_inode_lock_class(struct configfs_dirent *sd, |
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struct inode *inode) |
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{ |
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} |
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#endif /* CONFIG_LOCKDEP */ |
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int configfs_create(struct dentry * dentry, umode_t mode, int (*init)(struct inode *)) |
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{ |
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int error = 0; |
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struct inode *inode = NULL; |
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struct configfs_dirent *sd; |
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struct inode *p_inode; |
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if (!dentry) |
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return -ENOENT; |
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if (dentry->d_inode) |
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return -EEXIST; |
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sd = dentry->d_fsdata; |
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inode = configfs_new_inode(mode, sd, dentry->d_sb); |
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if (!inode) |
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return -ENOMEM; |
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p_inode = dentry->d_parent->d_inode; |
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p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME; |
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configfs_set_inode_lock_class(sd, inode); |
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if (init) { |
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error = init(inode); |
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if (error) { |
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iput(inode); |
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return error; |
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} |
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} |
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d_instantiate(dentry, inode); |
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if (S_ISDIR(mode) || S_ISLNK(mode)) |
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dget(dentry); /* pin link and directory dentries in core */ |
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return error; |
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} |
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/* |
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* Get the name for corresponding element represented by the given configfs_dirent |
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*/ |
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const unsigned char * configfs_get_name(struct configfs_dirent *sd) |
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{ |
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struct configfs_attribute *attr; |
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BUG_ON(!sd || !sd->s_element); |
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/* These always have a dentry, so use that */ |
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if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK)) |
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return sd->s_dentry->d_name.name; |
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if (sd->s_type & CONFIGFS_ITEM_ATTR) { |
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attr = sd->s_element; |
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return attr->ca_name; |
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} |
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return NULL; |
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} |
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/* |
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* Unhashes the dentry corresponding to given configfs_dirent |
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* Called with parent inode's i_mutex held. |
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*/ |
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void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent) |
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{ |
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struct dentry * dentry = sd->s_dentry; |
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if (dentry) { |
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spin_lock(&dentry->d_lock); |
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if (!(d_unhashed(dentry) && dentry->d_inode)) { |
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dget_dlock(dentry); |
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__d_drop(dentry); |
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spin_unlock(&dentry->d_lock); |
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simple_unlink(parent->d_inode, dentry); |
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} else |
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spin_unlock(&dentry->d_lock); |
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} |
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} |
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void configfs_hash_and_remove(struct dentry * dir, const char * name) |
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{ |
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struct configfs_dirent * sd; |
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struct configfs_dirent * parent_sd = dir->d_fsdata; |
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if (dir->d_inode == NULL) |
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/* no inode means this hasn't been made visible yet */ |
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return; |
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mutex_lock(&dir->d_inode->i_mutex); |
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list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
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if (!sd->s_element) |
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continue; |
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if (!strcmp(configfs_get_name(sd), name)) { |
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spin_lock(&configfs_dirent_lock); |
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list_del_init(&sd->s_sibling); |
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spin_unlock(&configfs_dirent_lock); |
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configfs_drop_dentry(sd, dir); |
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configfs_put(sd); |
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break; |
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} |
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} |
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mutex_unlock(&dir->d_inode->i_mutex); |
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} |
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int __init configfs_inode_init(void) |
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{ |
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return bdi_init(&configfs_backing_dev_info); |
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} |
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void configfs_inode_exit(void) |
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{ |
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bdi_destroy(&configfs_backing_dev_info); |
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}
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