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![Al Viro](/assets/img/avatar_default.png)
For anything NFS-exported we do _not_ want to unlock new inode before it has grown an alias; original set of fixes got the ordering right, but missed the nasty complication in case of lockdep being enabled - unlock_new_inode() does lockdep_annotate_inode_mutex_key(inode) which can only be done before anyone gets a chance to touch ->i_mutex. Unfortunately, flipping the order and doing unlock_new_inode() before d_instantiate() opens a window when mkdir can race with open-by-fhandle on a guessed fhandle, leading to multiple aliases for a directory inode and all the breakage that follows from that. Correct solution: a new primitive (d_instantiate_new()) combining these two in the right order - lockdep annotate, then d_instantiate(), then the rest of unlock_new_inode(). All combinations of d_instantiate() with unlock_new_inode() should be converted to that. Cc: stable@kernel.org # 2.6.29 and later Tested-by: Mike Marshall <hubcap@omnibond.com> Reviewed-by: Andreas Dilger <adilger@dilger.ca> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
340 lines
7.3 KiB
C
340 lines
7.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/ufs/namei.c
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*
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* Migration to usage of "page cache" on May 2006 by
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* Evgeniy Dushistov <dushistov@mail.ru> based on ext2 code base.
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*
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* Copyright (C) 1998
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* Daniel Pirkl <daniel.pirkl@email.cz>
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* Charles University, Faculty of Mathematics and Physics
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*
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* from
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*
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* linux/fs/ext2/namei.c
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* from
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*
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* linux/fs/minix/namei.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* Big-endian to little-endian byte-swapping/bitmaps by
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* David S. Miller (davem@caip.rutgers.edu), 1995
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*/
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#include <linux/time.h>
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#include <linux/fs.h>
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#include "ufs_fs.h"
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#include "ufs.h"
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#include "util.h"
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static inline int ufs_add_nondir(struct dentry *dentry, struct inode *inode)
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{
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int err = ufs_add_link(dentry, inode);
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if (!err) {
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d_instantiate_new(dentry, inode);
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return 0;
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}
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inode_dec_link_count(inode);
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unlock_new_inode(inode);
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iput(inode);
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return err;
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}
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static struct dentry *ufs_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
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{
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struct inode * inode = NULL;
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ino_t ino;
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if (dentry->d_name.len > UFS_MAXNAMLEN)
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return ERR_PTR(-ENAMETOOLONG);
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ino = ufs_inode_by_name(dir, &dentry->d_name);
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if (ino)
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inode = ufs_iget(dir->i_sb, ino);
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return d_splice_alias(inode, dentry);
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}
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/*
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* By the time this is called, we already have created
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* the directory cache entry for the new file, but it
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* is so far negative - it has no inode.
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*
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* If the create succeeds, we fill in the inode information
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* with d_instantiate().
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*/
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static int ufs_create (struct inode * dir, struct dentry * dentry, umode_t mode,
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bool excl)
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{
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struct inode *inode;
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inode = ufs_new_inode(dir, mode);
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if (IS_ERR(inode))
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return PTR_ERR(inode);
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inode->i_op = &ufs_file_inode_operations;
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inode->i_fop = &ufs_file_operations;
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inode->i_mapping->a_ops = &ufs_aops;
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mark_inode_dirty(inode);
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return ufs_add_nondir(dentry, inode);
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}
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static int ufs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
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{
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struct inode *inode;
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int err;
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if (!old_valid_dev(rdev))
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return -EINVAL;
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inode = ufs_new_inode(dir, mode);
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err = PTR_ERR(inode);
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if (!IS_ERR(inode)) {
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init_special_inode(inode, mode, rdev);
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ufs_set_inode_dev(inode->i_sb, UFS_I(inode), rdev);
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mark_inode_dirty(inode);
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err = ufs_add_nondir(dentry, inode);
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}
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return err;
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}
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static int ufs_symlink (struct inode * dir, struct dentry * dentry,
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const char * symname)
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{
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struct super_block * sb = dir->i_sb;
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int err;
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unsigned l = strlen(symname)+1;
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struct inode * inode;
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if (l > sb->s_blocksize)
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return -ENAMETOOLONG;
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inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
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err = PTR_ERR(inode);
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if (IS_ERR(inode))
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return err;
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if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
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/* slow symlink */
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inode->i_op = &page_symlink_inode_operations;
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inode_nohighmem(inode);
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inode->i_mapping->a_ops = &ufs_aops;
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err = page_symlink(inode, symname, l);
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if (err)
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goto out_fail;
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} else {
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/* fast symlink */
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inode->i_op = &simple_symlink_inode_operations;
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inode->i_link = (char *)UFS_I(inode)->i_u1.i_symlink;
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memcpy(inode->i_link, symname, l);
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inode->i_size = l-1;
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}
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mark_inode_dirty(inode);
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return ufs_add_nondir(dentry, inode);
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out_fail:
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inode_dec_link_count(inode);
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unlock_new_inode(inode);
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iput(inode);
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return err;
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}
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static int ufs_link (struct dentry * old_dentry, struct inode * dir,
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struct dentry *dentry)
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{
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struct inode *inode = d_inode(old_dentry);
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int error;
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inode->i_ctime = current_time(inode);
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inode_inc_link_count(inode);
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ihold(inode);
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error = ufs_add_link(dentry, inode);
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if (error) {
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inode_dec_link_count(inode);
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iput(inode);
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} else
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d_instantiate(dentry, inode);
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return error;
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}
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static int ufs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
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{
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struct inode * inode;
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int err;
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inode_inc_link_count(dir);
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inode = ufs_new_inode(dir, S_IFDIR|mode);
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err = PTR_ERR(inode);
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if (IS_ERR(inode))
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goto out_dir;
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inode->i_op = &ufs_dir_inode_operations;
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inode->i_fop = &ufs_dir_operations;
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inode->i_mapping->a_ops = &ufs_aops;
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inode_inc_link_count(inode);
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err = ufs_make_empty(inode, dir);
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if (err)
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goto out_fail;
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err = ufs_add_link(dentry, inode);
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if (err)
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goto out_fail;
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d_instantiate_new(dentry, inode);
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return 0;
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out_fail:
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inode_dec_link_count(inode);
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inode_dec_link_count(inode);
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unlock_new_inode(inode);
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iput (inode);
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out_dir:
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inode_dec_link_count(dir);
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return err;
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}
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static int ufs_unlink(struct inode *dir, struct dentry *dentry)
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{
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struct inode * inode = d_inode(dentry);
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struct ufs_dir_entry *de;
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struct page *page;
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int err = -ENOENT;
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de = ufs_find_entry(dir, &dentry->d_name, &page);
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if (!de)
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goto out;
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err = ufs_delete_entry(dir, de, page);
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if (err)
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goto out;
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inode->i_ctime = dir->i_ctime;
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inode_dec_link_count(inode);
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err = 0;
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out:
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return err;
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}
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static int ufs_rmdir (struct inode * dir, struct dentry *dentry)
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{
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struct inode * inode = d_inode(dentry);
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int err= -ENOTEMPTY;
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if (ufs_empty_dir (inode)) {
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err = ufs_unlink(dir, dentry);
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if (!err) {
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inode->i_size = 0;
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inode_dec_link_count(inode);
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inode_dec_link_count(dir);
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}
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}
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return err;
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}
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static int ufs_rename(struct inode *old_dir, struct dentry *old_dentry,
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struct inode *new_dir, struct dentry *new_dentry,
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unsigned int flags)
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{
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struct inode *old_inode = d_inode(old_dentry);
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struct inode *new_inode = d_inode(new_dentry);
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struct page *dir_page = NULL;
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struct ufs_dir_entry * dir_de = NULL;
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struct page *old_page;
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struct ufs_dir_entry *old_de;
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int err = -ENOENT;
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if (flags & ~RENAME_NOREPLACE)
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return -EINVAL;
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old_de = ufs_find_entry(old_dir, &old_dentry->d_name, &old_page);
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if (!old_de)
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goto out;
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if (S_ISDIR(old_inode->i_mode)) {
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err = -EIO;
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dir_de = ufs_dotdot(old_inode, &dir_page);
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if (!dir_de)
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goto out_old;
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}
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if (new_inode) {
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struct page *new_page;
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struct ufs_dir_entry *new_de;
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err = -ENOTEMPTY;
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if (dir_de && !ufs_empty_dir(new_inode))
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goto out_dir;
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err = -ENOENT;
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new_de = ufs_find_entry(new_dir, &new_dentry->d_name, &new_page);
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if (!new_de)
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goto out_dir;
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ufs_set_link(new_dir, new_de, new_page, old_inode, 1);
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new_inode->i_ctime = current_time(new_inode);
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if (dir_de)
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drop_nlink(new_inode);
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inode_dec_link_count(new_inode);
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} else {
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err = ufs_add_link(new_dentry, old_inode);
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if (err)
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goto out_dir;
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if (dir_de)
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inode_inc_link_count(new_dir);
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}
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/*
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* Like most other Unix systems, set the ctime for inodes on a
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* rename.
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*/
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old_inode->i_ctime = current_time(old_inode);
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ufs_delete_entry(old_dir, old_de, old_page);
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mark_inode_dirty(old_inode);
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if (dir_de) {
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if (old_dir != new_dir)
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ufs_set_link(old_inode, dir_de, dir_page, new_dir, 0);
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else {
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kunmap(dir_page);
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put_page(dir_page);
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}
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inode_dec_link_count(old_dir);
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}
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return 0;
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out_dir:
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if (dir_de) {
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kunmap(dir_page);
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put_page(dir_page);
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}
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out_old:
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kunmap(old_page);
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put_page(old_page);
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out:
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return err;
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}
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const struct inode_operations ufs_dir_inode_operations = {
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.create = ufs_create,
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.lookup = ufs_lookup,
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.link = ufs_link,
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.unlink = ufs_unlink,
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.symlink = ufs_symlink,
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.mkdir = ufs_mkdir,
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.rmdir = ufs_rmdir,
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.mknod = ufs_mknod,
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.rename = ufs_rename,
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};
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