| // 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 |
| * viro@parcelfarce.linux.theplanet.co.uk |
| * |
| * 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 (card@masi.ibp.fr) |
| * 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 (davem@caip.rutgers.edu), 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->i_ctime = current_time(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 page * page; |
| void *page_addr; |
| int err; |
| |
| err = dquot_initialize(dir); |
| if (err) |
| goto out; |
| |
| de = ext2_find_entry(dir, &dentry->d_name, &page, &page_addr); |
| if (IS_ERR(de)) { |
| err = PTR_ERR(de); |
| goto out; |
| } |
| |
| err = ext2_delete_entry (de, page, page_addr); |
| ext2_put_page(page, page_addr); |
| if (err) |
| goto out; |
| |
| inode->i_ctime = dir->i_ctime; |
| 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 page * dir_page = NULL; |
| void *dir_page_addr; |
| struct ext2_dir_entry_2 * dir_de = NULL; |
| struct page * old_page; |
| void *old_page_addr; |
| struct ext2_dir_entry_2 * old_de; |
| int err; |
| |
| if (flags & ~RENAME_NOREPLACE) |
| return -EINVAL; |
| |
| err = dquot_initialize(old_dir); |
| if (err) |
| goto out; |
| |
| err = dquot_initialize(new_dir); |
| if (err) |
| goto out; |
| |
| old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_page, |
| &old_page_addr); |
| if (IS_ERR(old_de)) { |
| err = PTR_ERR(old_de); |
| goto out; |
| } |
| |
| if (S_ISDIR(old_inode->i_mode)) { |
| err = -EIO; |
| dir_de = ext2_dotdot(old_inode, &dir_page, &dir_page_addr); |
| if (!dir_de) |
| goto out_old; |
| } |
| |
| if (new_inode) { |
| void *page_addr; |
| struct page *new_page; |
| struct ext2_dir_entry_2 *new_de; |
| |
| err = -ENOTEMPTY; |
| if (dir_de && !ext2_empty_dir (new_inode)) |
| goto out_dir; |
| |
| new_de = ext2_find_entry(new_dir, &new_dentry->d_name, |
| &new_page, &page_addr); |
| if (IS_ERR(new_de)) { |
| err = PTR_ERR(new_de); |
| goto out_dir; |
| } |
| err = ext2_set_link(new_dir, new_de, new_page, page_addr, |
| old_inode, true); |
| ext2_put_page(new_page, page_addr); |
| if (err) |
| goto out_dir; |
| new_inode->i_ctime = current_time(new_inode); |
| if (dir_de) |
| 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 (dir_de) |
| inode_inc_link_count(new_dir); |
| } |
| |
| /* |
| * Like most other Unix systems, set the ctime for inodes on a |
| * rename. |
| */ |
| old_inode->i_ctime = current_time(old_inode); |
| mark_inode_dirty(old_inode); |
| |
| ext2_delete_entry(old_de, old_page, old_page_addr); |
| |
| if (dir_de) { |
| if (old_dir != new_dir) { |
| err = ext2_set_link(old_inode, dir_de, dir_page, |
| dir_page_addr, new_dir, false); |
| |
| } |
| ext2_put_page(dir_page, dir_page_addr); |
| inode_dec_link_count(old_dir); |
| } |
| |
| out_old: |
| ext2_put_page(old_page, old_page_addr); |
| out: |
| return err; |
| |
| out_dir: |
| if (dir_de) |
| ext2_put_page(dir_page, dir_page_addr); |
| goto out_old; |
| } |
| |
| 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, |
| }; |