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1// SPDX-License-Identifier: GPL-2.02/*3 * linux/fs/ext2/namei.c4 *5 * Rewrite to pagecache. Almost all code had been changed, so blame me6 * if the things go wrong. Please, send bug reports to7 * viro@parcelfarce.linux.theplanet.co.uk8 *9 * Stuff here is basically a glue between the VFS and generic UNIXish10 * filesystem that keeps everything in pagecache. All knowledge of the11 * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable12 * and it's easier to debug that way. In principle we might want to13 * generalize that a bit and turn it into a library. Or not.14 *15 * The only non-static object here is ext2_dir_inode_operations.16 *17 * TODO: get rid of kmap() use, add readahead.18 *19 * Copyright (C) 1992, 1993, 1994, 199520 * Remy Card (card@masi.ibp.fr)21 * Laboratoire MASI - Institut Blaise Pascal22 * Universite Pierre et Marie Curie (Paris VI)23 *24 * from25 *26 * linux/fs/minix/namei.c27 *28 * Copyright (C) 1991, 1992 Linus Torvalds29 *30 * Big-endian to little-endian byte-swapping/bitmaps by31 * David S. Miller (davem@caip.rutgers.edu), 199532 */33 34#include <linux/pagemap.h>35#include <linux/quotaops.h>36#include "ext2.h"37#include "xattr.h"38#include "acl.h"39 40static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)41{42 int err = ext2_add_link(dentry, inode);43 if (!err) {44 d_instantiate_new(dentry, inode);45 return 0;46 }47 inode_dec_link_count(inode);48 discard_new_inode(inode);49 return err;50}51 52/*53 * Methods themselves.54 */55 56static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)57{58 struct inode * inode;59 ino_t ino;60 int res;61 62 if (dentry->d_name.len > EXT2_NAME_LEN)63 return ERR_PTR(-ENAMETOOLONG);64 65 res = ext2_inode_by_name(dir, &dentry->d_name, &ino);66 if (res) {67 if (res != -ENOENT)68 return ERR_PTR(res);69 inode = NULL;70 } else {71 inode = ext2_iget(dir->i_sb, ino);72 if (inode == ERR_PTR(-ESTALE)) {73 ext2_error(dir->i_sb, __func__,74 "deleted inode referenced: %lu",75 (unsigned long) ino);76 return ERR_PTR(-EIO);77 }78 }79 return d_splice_alias(inode, dentry);80}81 82struct dentry *ext2_get_parent(struct dentry *child)83{84 ino_t ino;85 int res;86 87 res = ext2_inode_by_name(d_inode(child), &dotdot_name, &ino);88 if (res)89 return ERR_PTR(res);90 91 return d_obtain_alias(ext2_iget(child->d_sb, ino));92} 93 94/*95 * By the time this is called, we already have created96 * the directory cache entry for the new file, but it97 * is so far negative - it has no inode.98 *99 * If the create succeeds, we fill in the inode information100 * with d_instantiate(). 101 */102static int ext2_create (struct mnt_idmap * idmap,103 struct inode * dir, struct dentry * dentry,104 umode_t mode, bool excl)105{106 struct inode *inode;107 int err;108 109 err = dquot_initialize(dir);110 if (err)111 return err;112 113 inode = ext2_new_inode(dir, mode, &dentry->d_name);114 if (IS_ERR(inode))115 return PTR_ERR(inode);116 117 ext2_set_file_ops(inode);118 mark_inode_dirty(inode);119 return ext2_add_nondir(dentry, inode);120}121 122static int ext2_tmpfile(struct mnt_idmap *idmap, struct inode *dir,123 struct file *file, umode_t mode)124{125 struct inode *inode = ext2_new_inode(dir, mode, NULL);126 if (IS_ERR(inode))127 return PTR_ERR(inode);128 129 ext2_set_file_ops(inode);130 mark_inode_dirty(inode);131 d_tmpfile(file, inode);132 unlock_new_inode(inode);133 return finish_open_simple(file, 0);134}135 136static int ext2_mknod (struct mnt_idmap * idmap, struct inode * dir,137 struct dentry *dentry, umode_t mode, dev_t rdev)138{139 struct inode * inode;140 int err;141 142 err = dquot_initialize(dir);143 if (err)144 return err;145 146 inode = ext2_new_inode (dir, mode, &dentry->d_name);147 err = PTR_ERR(inode);148 if (!IS_ERR(inode)) {149 init_special_inode(inode, inode->i_mode, rdev);150 inode->i_op = &ext2_special_inode_operations;151 mark_inode_dirty(inode);152 err = ext2_add_nondir(dentry, inode);153 }154 return err;155}156 157static int ext2_symlink (struct mnt_idmap * idmap, struct inode * dir,158 struct dentry * dentry, const char * symname)159{160 struct super_block * sb = dir->i_sb;161 int err = -ENAMETOOLONG;162 unsigned l = strlen(symname)+1;163 struct inode * inode;164 165 if (l > sb->s_blocksize)166 goto out;167 168 err = dquot_initialize(dir);169 if (err)170 goto out;171 172 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name);173 err = PTR_ERR(inode);174 if (IS_ERR(inode))175 goto out;176 177 if (l > sizeof (EXT2_I(inode)->i_data)) {178 /* slow symlink */179 inode->i_op = &ext2_symlink_inode_operations;180 inode_nohighmem(inode);181 inode->i_mapping->a_ops = &ext2_aops;182 err = page_symlink(inode, symname, l);183 if (err)184 goto out_fail;185 } else {186 /* fast symlink */187 inode->i_op = &ext2_fast_symlink_inode_operations;188 inode->i_link = (char*)EXT2_I(inode)->i_data;189 memcpy(inode->i_link, symname, l);190 inode->i_size = l-1;191 }192 mark_inode_dirty(inode);193 194 err = ext2_add_nondir(dentry, inode);195out:196 return err;197 198out_fail:199 inode_dec_link_count(inode);200 discard_new_inode(inode);201 goto out;202}203 204static int ext2_link (struct dentry * old_dentry, struct inode * dir,205 struct dentry *dentry)206{207 struct inode *inode = d_inode(old_dentry);208 int err;209 210 err = dquot_initialize(dir);211 if (err)212 return err;213 214 inode_set_ctime_current(inode);215 inode_inc_link_count(inode);216 ihold(inode);217 218 err = ext2_add_link(dentry, inode);219 if (!err) {220 d_instantiate(dentry, inode);221 return 0;222 }223 inode_dec_link_count(inode);224 iput(inode);225 return err;226}227 228static int ext2_mkdir(struct mnt_idmap * idmap,229 struct inode * dir, struct dentry * dentry, umode_t mode)230{231 struct inode * inode;232 int err;233 234 err = dquot_initialize(dir);235 if (err)236 return err;237 238 inode_inc_link_count(dir);239 240 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name);241 err = PTR_ERR(inode);242 if (IS_ERR(inode))243 goto out_dir;244 245 inode->i_op = &ext2_dir_inode_operations;246 inode->i_fop = &ext2_dir_operations;247 inode->i_mapping->a_ops = &ext2_aops;248 249 inode_inc_link_count(inode);250 251 err = ext2_make_empty(inode, dir);252 if (err)253 goto out_fail;254 255 err = ext2_add_link(dentry, inode);256 if (err)257 goto out_fail;258 259 d_instantiate_new(dentry, inode);260out:261 return err;262 263out_fail:264 inode_dec_link_count(inode);265 inode_dec_link_count(inode);266 discard_new_inode(inode);267out_dir:268 inode_dec_link_count(dir);269 goto out;270}271 272static int ext2_unlink(struct inode *dir, struct dentry *dentry)273{274 struct inode *inode = d_inode(dentry);275 struct ext2_dir_entry_2 *de;276 struct folio *folio;277 int err;278 279 err = dquot_initialize(dir);280 if (err)281 goto out;282 283 de = ext2_find_entry(dir, &dentry->d_name, &folio);284 if (IS_ERR(de)) {285 err = PTR_ERR(de);286 goto out;287 }288 289 err = ext2_delete_entry(de, folio);290 folio_release_kmap(folio, de);291 if (err)292 goto out;293 294 inode_set_ctime_to_ts(inode, inode_get_ctime(dir));295 inode_dec_link_count(inode);296 err = 0;297out:298 return err;299}300 301static int ext2_rmdir (struct inode * dir, struct dentry *dentry)302{303 struct inode * inode = d_inode(dentry);304 int err = -ENOTEMPTY;305 306 if (ext2_empty_dir(inode)) {307 err = ext2_unlink(dir, dentry);308 if (!err) {309 inode->i_size = 0;310 inode_dec_link_count(inode);311 inode_dec_link_count(dir);312 }313 }314 return err;315}316 317static int ext2_rename (struct mnt_idmap * idmap,318 struct inode * old_dir, struct dentry * old_dentry,319 struct inode * new_dir, struct dentry * new_dentry,320 unsigned int flags)321{322 struct inode * old_inode = d_inode(old_dentry);323 struct inode * new_inode = d_inode(new_dentry);324 struct folio *dir_folio = NULL;325 struct ext2_dir_entry_2 * dir_de = NULL;326 struct folio * old_folio;327 struct ext2_dir_entry_2 * old_de;328 bool old_is_dir = S_ISDIR(old_inode->i_mode);329 int err;330 331 if (flags & ~RENAME_NOREPLACE)332 return -EINVAL;333 334 err = dquot_initialize(old_dir);335 if (err)336 return err;337 338 err = dquot_initialize(new_dir);339 if (err)340 return err;341 342 old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_folio);343 if (IS_ERR(old_de))344 return PTR_ERR(old_de);345 346 if (old_is_dir && old_dir != new_dir) {347 err = -EIO;348 dir_de = ext2_dotdot(old_inode, &dir_folio);349 if (!dir_de)350 goto out_old;351 }352 353 if (new_inode) {354 struct folio *new_folio;355 struct ext2_dir_entry_2 *new_de;356 357 err = -ENOTEMPTY;358 if (old_is_dir && !ext2_empty_dir(new_inode))359 goto out_dir;360 361 new_de = ext2_find_entry(new_dir, &new_dentry->d_name,362 &new_folio);363 if (IS_ERR(new_de)) {364 err = PTR_ERR(new_de);365 goto out_dir;366 }367 err = ext2_set_link(new_dir, new_de, new_folio, old_inode, true);368 folio_release_kmap(new_folio, new_de);369 if (err)370 goto out_dir;371 inode_set_ctime_current(new_inode);372 if (old_is_dir)373 drop_nlink(new_inode);374 inode_dec_link_count(new_inode);375 } else {376 err = ext2_add_link(new_dentry, old_inode);377 if (err)378 goto out_dir;379 if (old_is_dir)380 inode_inc_link_count(new_dir);381 }382 383 /*384 * Like most other Unix systems, set the ctime for inodes on a385 * rename.386 */387 inode_set_ctime_current(old_inode);388 mark_inode_dirty(old_inode);389 390 err = ext2_delete_entry(old_de, old_folio);391 if (!err && old_is_dir) {392 if (old_dir != new_dir)393 err = ext2_set_link(old_inode, dir_de, dir_folio,394 new_dir, false);395 396 inode_dec_link_count(old_dir);397 }398out_dir:399 if (dir_de)400 folio_release_kmap(dir_folio, dir_de);401out_old:402 folio_release_kmap(old_folio, old_de);403 return err;404}405 406const struct inode_operations ext2_dir_inode_operations = {407 .create = ext2_create,408 .lookup = ext2_lookup,409 .link = ext2_link,410 .unlink = ext2_unlink,411 .symlink = ext2_symlink,412 .mkdir = ext2_mkdir,413 .rmdir = ext2_rmdir,414 .mknod = ext2_mknod,415 .rename = ext2_rename,416 .listxattr = ext2_listxattr,417 .getattr = ext2_getattr,418 .setattr = ext2_setattr,419 .get_inode_acl = ext2_get_acl,420 .set_acl = ext2_set_acl,421 .tmpfile = ext2_tmpfile,422 .fileattr_get = ext2_fileattr_get,423 .fileattr_set = ext2_fileattr_set,424};425 426const struct inode_operations ext2_special_inode_operations = {427 .listxattr = ext2_listxattr,428 .getattr = ext2_getattr,429 .setattr = ext2_setattr,430 .get_inode_acl = ext2_get_acl,431 .set_acl = ext2_set_acl,432};433