// 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 user_namespace * mnt_userns, 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 user_namespace *mnt_userns, struct inode *dir, struct dentry *dentry, 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(dentry, inode); unlock_new_inode(inode); return 0; } static int ext2_mknod (struct user_namespace * mnt_userns, 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 user_namespace * mnt_userns, 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 user_namespace * mnt_userns, 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 user_namespace * mnt_userns, 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; } ext2_set_link(new_dir, new_de, new_page, page_addr, old_inode, 1); ext2_put_page(new_page, page_addr); 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) ext2_set_link(old_inode, dir_de, dir_page, dir_page_addr, new_dir, 0); ext2_put_page(dir_page, dir_page_addr); inode_dec_link_count(old_dir); } ext2_put_page(old_page, old_page_addr); return 0; out_dir: if (dir_de) ext2_put_page(dir_page, dir_page_addr); out_old: ext2_put_page(old_page, old_page_addr); out: 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_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_acl = ext2_get_acl, .set_acl = ext2_set_acl, };