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![Christian Brauner](/assets/img/avatar_default.png)
Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
340 lines
7.4 KiB
C
340 lines
7.4 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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discard_new_inode(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 user_namespace * mnt_userns,
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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 user_namespace *mnt_userns, struct inode *dir,
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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 user_namespace * mnt_userns, struct inode * dir,
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struct dentry * dentry, 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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discard_new_inode(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 user_namespace * mnt_userns, struct inode * dir,
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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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discard_new_inode(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 user_namespace *mnt_userns, struct inode *old_dir,
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struct dentry *old_dentry, struct inode *new_dir,
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struct dentry *new_dentry, 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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