450 lines
10 KiB
C
450 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/ext2/namei.c
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*
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* Rewrite to pagecache. Almost all code had been changed, so blame me
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* if the things go wrong. Please, send bug reports to
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* viro@parcelfarce.linux.theplanet.co.uk
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*
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* Stuff here is basically a glue between the VFS and generic UNIXish
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* filesystem that keeps everything in pagecache. All knowledge of the
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* directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
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* and it's easier to debug that way. In principle we might want to
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* generalize that a bit and turn it into a library. Or not.
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*
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* The only non-static object here is ext2_dir_inode_operations.
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*
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* TODO: get rid of kmap() use, add readahead.
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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/pagemap.h>
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#include <linux/quotaops.h>
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#include "ext2.h"
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#include "xattr.h"
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#include "acl.h"
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static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
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{
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int err = ext2_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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/*
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* Methods themselves.
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*/
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static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
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{
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struct inode * inode;
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ino_t ino;
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int res;
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if (dentry->d_name.len > EXT2_NAME_LEN)
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return ERR_PTR(-ENAMETOOLONG);
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res = ext2_inode_by_name(dir, &dentry->d_name, &ino);
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if (res) {
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if (res != -ENOENT)
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return ERR_PTR(res);
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inode = NULL;
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} else {
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inode = ext2_iget(dir->i_sb, ino);
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if (inode == ERR_PTR(-ESTALE)) {
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ext2_error(dir->i_sb, __func__,
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"deleted inode referenced: %lu",
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(unsigned long) ino);
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return ERR_PTR(-EIO);
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}
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}
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return d_splice_alias(inode, dentry);
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}
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struct dentry *ext2_get_parent(struct dentry *child)
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{
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ino_t ino;
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int res;
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res = ext2_inode_by_name(d_inode(child), &dotdot_name, &ino);
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if (res)
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return ERR_PTR(res);
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return d_obtain_alias(ext2_iget(child->d_sb, ino));
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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 ext2_create (struct user_namespace * mnt_userns,
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struct inode * dir, struct dentry * dentry,
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umode_t mode, bool excl)
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{
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struct inode *inode;
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int err;
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err = dquot_initialize(dir);
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if (err)
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return err;
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inode = ext2_new_inode(dir, mode, &dentry->d_name);
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if (IS_ERR(inode))
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return PTR_ERR(inode);
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ext2_set_file_ops(inode);
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mark_inode_dirty(inode);
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return ext2_add_nondir(dentry, inode);
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}
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static int ext2_tmpfile(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 = ext2_new_inode(dir, mode, NULL);
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if (IS_ERR(inode))
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return PTR_ERR(inode);
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ext2_set_file_ops(inode);
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mark_inode_dirty(inode);
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d_tmpfile(dentry, inode);
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unlock_new_inode(inode);
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return 0;
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}
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static int ext2_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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err = dquot_initialize(dir);
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if (err)
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return err;
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inode = ext2_new_inode (dir, mode, &dentry->d_name);
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err = PTR_ERR(inode);
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if (!IS_ERR(inode)) {
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init_special_inode(inode, inode->i_mode, rdev);
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inode->i_op = &ext2_special_inode_operations;
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mark_inode_dirty(inode);
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err = ext2_add_nondir(dentry, inode);
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}
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return err;
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}
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static int ext2_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 = -ENAMETOOLONG;
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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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goto out;
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err = dquot_initialize(dir);
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if (err)
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goto out;
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inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name);
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err = PTR_ERR(inode);
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if (IS_ERR(inode))
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goto out;
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if (l > sizeof (EXT2_I(inode)->i_data)) {
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/* slow symlink */
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inode->i_op = &ext2_symlink_inode_operations;
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inode_nohighmem(inode);
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if (test_opt(inode->i_sb, NOBH))
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inode->i_mapping->a_ops = &ext2_nobh_aops;
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else
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inode->i_mapping->a_ops = &ext2_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 = &ext2_fast_symlink_inode_operations;
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inode->i_link = (char*)EXT2_I(inode)->i_data;
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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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err = ext2_add_nondir(dentry, inode);
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out:
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return err;
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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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goto out;
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}
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static int ext2_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 err;
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err = dquot_initialize(dir);
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if (err)
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return err;
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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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err = ext2_add_link(dentry, inode);
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if (!err) {
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d_instantiate(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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iput(inode);
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return err;
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}
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static int ext2_mkdir(struct user_namespace * mnt_userns,
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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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err = dquot_initialize(dir);
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if (err)
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return err;
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inode_inc_link_count(dir);
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inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name);
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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 = &ext2_dir_inode_operations;
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inode->i_fop = &ext2_dir_operations;
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if (test_opt(inode->i_sb, NOBH))
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inode->i_mapping->a_ops = &ext2_nobh_aops;
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else
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inode->i_mapping->a_ops = &ext2_aops;
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inode_inc_link_count(inode);
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err = ext2_make_empty(inode, dir);
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if (err)
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goto out_fail;
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err = ext2_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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out:
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return err;
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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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goto out;
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}
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static int ext2_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 ext2_dir_entry_2 * de;
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struct page * page;
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void *page_addr;
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int err;
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err = dquot_initialize(dir);
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if (err)
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goto out;
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de = ext2_find_entry(dir, &dentry->d_name, &page, &page_addr);
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if (IS_ERR(de)) {
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err = PTR_ERR(de);
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goto out;
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}
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err = ext2_delete_entry (de, page);
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ext2_put_page(page, page_addr);
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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 ext2_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 (ext2_empty_dir(inode)) {
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err = ext2_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 ext2_rename (struct user_namespace * mnt_userns,
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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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void *dir_page_addr;
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struct ext2_dir_entry_2 * dir_de = NULL;
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struct page * old_page;
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void *old_page_addr;
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struct ext2_dir_entry_2 * old_de;
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int err;
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if (flags & ~RENAME_NOREPLACE)
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return -EINVAL;
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err = dquot_initialize(old_dir);
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if (err)
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goto out;
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err = dquot_initialize(new_dir);
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if (err)
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goto out;
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old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_page,
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&old_page_addr);
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if (IS_ERR(old_de)) {
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err = PTR_ERR(old_de);
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goto out;
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}
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if (S_ISDIR(old_inode->i_mode)) {
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err = -EIO;
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dir_de = ext2_dotdot(old_inode, &dir_page, &dir_page_addr);
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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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void *page_addr;
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struct page *new_page;
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struct ext2_dir_entry_2 *new_de;
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err = -ENOTEMPTY;
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if (dir_de && !ext2_empty_dir (new_inode))
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goto out_dir;
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new_de = ext2_find_entry(new_dir, &new_dentry->d_name,
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&new_page, &page_addr);
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if (IS_ERR(new_de)) {
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err = PTR_ERR(new_de);
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goto out_dir;
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}
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ext2_set_link(new_dir, new_de, new_page, page_addr, old_inode, 1);
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ext2_put_page(new_page, page_addr);
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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 = ext2_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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mark_inode_dirty(old_inode);
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ext2_delete_entry(old_de, old_page);
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if (dir_de) {
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if (old_dir != new_dir)
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ext2_set_link(old_inode, dir_de, dir_page,
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dir_page_addr, new_dir, 0);
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ext2_put_page(dir_page, dir_page_addr);
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inode_dec_link_count(old_dir);
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}
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ext2_put_page(old_page, old_page_addr);
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return 0;
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out_dir:
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if (dir_de)
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ext2_put_page(dir_page, dir_page_addr);
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out_old:
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ext2_put_page(old_page, old_page_addr);
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out:
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return err;
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}
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const struct inode_operations ext2_dir_inode_operations = {
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.create = ext2_create,
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.lookup = ext2_lookup,
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.link = ext2_link,
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.unlink = ext2_unlink,
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.symlink = ext2_symlink,
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.mkdir = ext2_mkdir,
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.rmdir = ext2_rmdir,
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.mknod = ext2_mknod,
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.rename = ext2_rename,
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.listxattr = ext2_listxattr,
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.getattr = ext2_getattr,
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.setattr = ext2_setattr,
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.get_acl = ext2_get_acl,
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.set_acl = ext2_set_acl,
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.tmpfile = ext2_tmpfile,
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.fileattr_get = ext2_fileattr_get,
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.fileattr_set = ext2_fileattr_set,
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};
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const struct inode_operations ext2_special_inode_operations = {
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.listxattr = ext2_listxattr,
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.getattr = ext2_getattr,
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.setattr = ext2_setattr,
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.get_acl = ext2_get_acl,
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.set_acl = ext2_set_acl,
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};
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