// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/ext2/namei.c
*
* Rewrite to pagecache. Almost all code had been changed, so blame me
* if the things go wrong. Please, send bug reports to
* [email protected]
*
* Stuff here is basically a glue between the VFS and generic UNIXish
* filesystem that keeps everything in pagecache. All knowledge of the
* directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
* and it's easier to debug that way. In principle we might want to
* generalize that a bit and turn it into a library. Or not.
*
* The only non-static object here is ext2_dir_inode_operations.
*
* TODO: get rid of kmap() use, add readahead.
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card ([email protected])
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/namei.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller ([email protected]), 1995
*/
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include "ext2.h"
#include "xattr.h"
#include "acl.h"
static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
{
int err = ext2_add_link(dentry, inode);
if (!err) {
d_instantiate_new(dentry, inode);
return 0;
}
inode_dec_link_count(inode);
discard_new_inode(inode);
return err;
}
/*
* Methods themselves.
*/
static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
{
struct inode * inode;
ino_t ino;
int res;
if (dentry->d_name.len > EXT2_NAME_LEN)
return ERR_PTR(-ENAMETOOLONG);
res = ext2_inode_by_name(dir, &dentry->d_name, &ino);
if (res) {
if (res != -ENOENT)
return ERR_PTR(res);
inode = NULL;
} else {
inode = ext2_iget(dir->i_sb, ino);
if (inode == ERR_PTR(-ESTALE)) {
ext2_error(dir->i_sb, __func__,
"deleted inode referenced: %lu",
(unsigned long) ino);
return ERR_PTR(-EIO);
}
}
return d_splice_alias(inode, dentry);
}
struct dentry *ext2_get_parent(struct dentry *child)
{
ino_t ino;
int res;
res = ext2_inode_by_name(d_inode(child), &dotdot_name, &ino);
if (res)
return ERR_PTR(res);
return d_obtain_alias(ext2_iget(child->d_sb, ino));
}
/*
* By the time this is called, we already have created
* the directory cache entry for the new file, but it
* is so far negative - it has no inode.
*
* If the create succeeds, we fill in the inode information
* with d_instantiate().
*/
static int ext2_create (struct mnt_idmap * idmap,
struct inode * dir, struct dentry * dentry,
umode_t mode, bool excl)
{
struct inode *inode;
int err;
err = dquot_initialize(dir);
if (err)
return err;
inode = ext2_new_inode(dir, mode, &dentry->d_name);
if (IS_ERR(inode))
return PTR_ERR(inode);
ext2_set_file_ops(inode);
mark_inode_dirty(inode);
return ext2_add_nondir(dentry, inode);
}
static int ext2_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
struct file *file, umode_t mode)
{
struct inode *inode = ext2_new_inode(dir, mode, NULL);
if (IS_ERR(inode))
return PTR_ERR(inode);
ext2_set_file_ops(inode);
mark_inode_dirty(inode);
d_tmpfile(file, inode);
unlock_new_inode(inode);
return finish_open_simple(file, 0);
}
static int ext2_mknod (struct mnt_idmap * idmap, struct inode * dir,
struct dentry *dentry, umode_t mode, dev_t rdev)
{
struct inode * inode;
int err;
err = dquot_initialize(dir);
if (err)
return err;
inode = ext2_new_inode (dir, mode, &dentry->d_name);
err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
init_special_inode(inode, inode->i_mode, rdev);
inode->i_op = &ext2_special_inode_operations;
mark_inode_dirty(inode);
err = ext2_add_nondir(dentry, inode);
}
return err;
}
static int ext2_symlink (struct mnt_idmap * idmap, struct inode * dir,
struct dentry * dentry, const char * symname)
{
struct super_block * sb = dir->i_sb;
int err = -ENAMETOOLONG;
unsigned l = strlen(symname)+1;
struct inode * inode;
if (l > sb->s_blocksize)
goto out;
err = dquot_initialize(dir);
if (err)
goto out;
inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out;
if (l > sizeof (EXT2_I(inode)->i_data)) {
/* slow symlink */
inode->i_op = &ext2_symlink_inode_operations;
inode_nohighmem(inode);
inode->i_mapping->a_ops = &ext2_aops;
err = page_symlink(inode, symname, l);
if (err)
goto out_fail;
} else {
/* fast symlink */
inode->i_op = &ext2_fast_symlink_inode_operations;
inode->i_link = (char*)EXT2_I(inode)->i_data;
memcpy(inode->i_link, symname, l);
inode->i_size = l-1;
}
mark_inode_dirty(inode);
err = ext2_add_nondir(dentry, inode);
out:
return err;
out_fail:
inode_dec_link_count(inode);
discard_new_inode(inode);
goto out;
}
static int ext2_link (struct dentry * old_dentry, struct inode * dir,
struct dentry *dentry)
{
struct inode *inode = d_inode(old_dentry);
int err;
err = dquot_initialize(dir);
if (err)
return err;
inode_set_ctime_current(inode);
inode_inc_link_count(inode);
ihold(inode);
err = ext2_add_link(dentry, inode);
if (!err) {
d_instantiate(dentry, inode);
return 0;
}
inode_dec_link_count(inode);
iput(inode);
return err;
}
static int ext2_mkdir(struct mnt_idmap * idmap,
struct inode * dir, struct dentry * dentry, umode_t mode)
{
struct inode * inode;
int err;
err = dquot_initialize(dir);
if (err)
return err;
inode_inc_link_count(dir);
inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_dir;
inode->i_op = &ext2_dir_inode_operations;
inode->i_fop = &ext2_dir_operations;
inode->i_mapping->a_ops = &ext2_aops;
inode_inc_link_count(inode);
err = ext2_make_empty(inode, dir);
if (err)
goto out_fail;
err = ext2_add_link(dentry, inode);
if (err)
goto out_fail;
d_instantiate_new(dentry, inode);
out:
return err;
out_fail:
inode_dec_link_count(inode);
inode_dec_link_count(inode);
discard_new_inode(inode);
out_dir:
inode_dec_link_count(dir);
goto out;
}
static int ext2_unlink(struct inode *dir, struct dentry *dentry)
{
struct inode *inode = d_inode(dentry);
struct ext2_dir_entry_2 *de;
struct folio *folio;
int err;
err = dquot_initialize(dir);
if (err)
goto out;
de = ext2_find_entry(dir, &dentry->d_name, &folio);
if (IS_ERR(de)) {
err = PTR_ERR(de);
goto out;
}
err = ext2_delete_entry(de, folio);
folio_release_kmap(folio, de);
if (err)
goto out;
inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
inode_dec_link_count(inode);
err = 0;
out:
return err;
}
static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
{
struct inode * inode = d_inode(dentry);
int err = -ENOTEMPTY;
if (ext2_empty_dir(inode)) {
err = ext2_unlink(dir, dentry);
if (!err) {
inode->i_size = 0;
inode_dec_link_count(inode);
inode_dec_link_count(dir);
}
}
return err;
}
static int ext2_rename (struct mnt_idmap * idmap,
struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry,
unsigned int flags)
{
struct inode * old_inode = d_inode(old_dentry);
struct inode * new_inode = d_inode(new_dentry);
struct folio *dir_folio = NULL;
struct ext2_dir_entry_2 * dir_de = NULL;
struct folio * old_folio;
struct ext2_dir_entry_2 * old_de;
bool old_is_dir = S_ISDIR(old_inode->i_mode);
int err;
if (flags & ~RENAME_NOREPLACE)
return -EINVAL;
err = dquot_initialize(old_dir);
if (err)
return err;
err = dquot_initialize(new_dir);
if (err)
return err;
old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_folio);
if (IS_ERR(old_de))
return PTR_ERR(old_de);
if (old_is_dir && old_dir != new_dir) {
err = -EIO;
dir_de = ext2_dotdot(old_inode, &dir_folio);
if (!dir_de)
goto out_old;
}
if (new_inode) {
struct folio *new_folio;
struct ext2_dir_entry_2 *new_de;
err = -ENOTEMPTY;
if (old_is_dir && !ext2_empty_dir(new_inode))
goto out_dir;
new_de = ext2_find_entry(new_dir, &new_dentry->d_name,
&new_folio);
if (IS_ERR(new_de)) {
err = PTR_ERR(new_de);
goto out_dir;
}
err = ext2_set_link(new_dir, new_de, new_folio, old_inode, true);
folio_release_kmap(new_folio, new_de);
if (err)
goto out_dir;
inode_set_ctime_current(new_inode);
if (old_is_dir)
drop_nlink(new_inode);
inode_dec_link_count(new_inode);
} else {
err = ext2_add_link(new_dentry, old_inode);
if (err)
goto out_dir;
if (old_is_dir)
inode_inc_link_count(new_dir);
}
/*
* Like most other Unix systems, set the ctime for inodes on a
* rename.
*/
inode_set_ctime_current(old_inode);
mark_inode_dirty(old_inode);
err = ext2_delete_entry(old_de, old_folio);
if (!err && old_is_dir) {
if (old_dir != new_dir)
err = ext2_set_link(old_inode, dir_de, dir_folio,
new_dir, false);
inode_dec_link_count(old_dir);
}
out_dir:
if (dir_de)
folio_release_kmap(dir_folio, dir_de);
out_old:
folio_release_kmap(old_folio, old_de);
return err;
}
const struct inode_operations ext2_dir_inode_operations = {
.create = ext2_create,
.lookup = ext2_lookup,
.link = ext2_link,
.unlink = ext2_unlink,
.symlink = ext2_symlink,
.mkdir = ext2_mkdir,
.rmdir = ext2_rmdir,
.mknod = ext2_mknod,
.rename = ext2_rename,
.listxattr = ext2_listxattr,
.getattr = ext2_getattr,
.setattr = ext2_setattr,
.get_inode_acl = ext2_get_acl,
.set_acl = ext2_set_acl,
.tmpfile = ext2_tmpfile,
.fileattr_get = ext2_fileattr_get,
.fileattr_set = ext2_fileattr_set,
};
const struct inode_operations ext2_special_inode_operations = {
.listxattr = ext2_listxattr,
.getattr = ext2_getattr,
.setattr = ext2_setattr,
.get_inode_acl = ext2_get_acl,
.set_acl = ext2_set_acl,
};
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