| 1 | |
| 2 | |
| 3 | *
|
| 4 | * Copyright (C) 2011 Novell Inc.
|
| 5 |
|
| 6 |
|
| 7 | #include <linux/fs.h>
|
| 8 | #include <linux/namei.h>
|
| 9 | #include <linux/xattr.h>
|
| 10 | #include <linux/security.h>
|
| 11 | #include <linux/cred.h>
|
| 12 | #include <linux/module.h>
|
| 13 | #include <linux/posix_acl.h>
|
| 14 | #include <linux/posix_acl_xattr.h>
|
| 15 | #include <linux/atomic.h>
|
| 16 | #include <linux/ratelimit.h>
|
| 17 | #include <linux/backing-file.h>
|
| 18 | #include "overlayfs.h"
|
| 19 |
|
| 20 | static unsigned short ovl_redirect_max = 256;
|
| 21 | module_param_named(redirect_max, ovl_redirect_max, ushort, 0644);
|
| 22 | MODULE_PARM_DESC(redirect_max,
|
| 23 | "Maximum length of absolute redirect xattr value");
|
| 24 |
|
| 25 | static int ovl_set_redirect(struct dentry *dentry, bool samedir);
|
| 26 |
|
| 27 | static int ovl_cleanup_locked(struct ovl_fs *ofs, struct inode *wdir,
|
| 28 | struct dentry *wdentry)
|
| 29 | {
|
| 30 | int err;
|
| 31 |
|
| 32 | dget(wdentry);
|
| 33 | if (d_is_dir(wdentry))
|
| 34 | err = ovl_do_rmdir(ofs, wdir, wdentry);
|
| 35 | else
|
| 36 | err = ovl_do_unlink(ofs, wdir, wdentry);
|
| 37 | dput(wdentry);
|
| 38 |
|
| 39 | if (err) {
|
| 40 | pr_err("cleanup of '%pd2' failed (%i)\n",
|
| 41 | wdentry, err);
|
| 42 | }
|
| 43 |
|
| 44 | return err;
|
| 45 | }
|
| 46 |
|
| 47 | int ovl_cleanup(struct ovl_fs *ofs, struct dentry *workdir,
|
| 48 | struct dentry *wdentry)
|
| 49 | {
|
| 50 | wdentry = start_removing_dentry(workdir, wdentry);
|
| 51 | if (IS_ERR(wdentry))
|
| 52 | return PTR_ERR(wdentry);
|
| 53 |
|
| 54 | ovl_cleanup_locked(ofs, workdir->d_inode, wdentry);
|
| 55 | end_removing(wdentry);
|
| 56 |
|
| 57 | return 0;
|
| 58 | }
|
| 59 |
|
| 60 | void ovl_tempname(char name[OVL_TEMPNAME_SIZE])
|
| 61 | {
|
| 62 | static atomic_t temp_id = ATOMIC_INIT(0);
|
| 63 |
|
| 64 |
|
| 65 | snprintf(name, OVL_TEMPNAME_SIZE, "#%x", atomic_inc_return(&temp_id));
|
| 66 | }
|
| 67 |
|
| 68 | static struct dentry *ovl_start_creating_temp(struct ovl_fs *ofs,
|
| 69 | struct dentry *workdir,
|
| 70 | char name[OVL_TEMPNAME_SIZE])
|
| 71 | {
|
| 72 | ovl_tempname(name);
|
| 73 | return start_creating(ovl_upper_mnt_idmap(ofs), workdir,
|
| 74 | &QSTR(name));
|
| 75 | }
|
| 76 |
|
| 77 | static struct dentry *ovl_whiteout(struct ovl_fs *ofs)
|
| 78 | {
|
| 79 | int err;
|
| 80 | struct dentry *whiteout, *link;
|
| 81 | struct dentry *workdir = ofs->workdir;
|
| 82 | struct inode *wdir = workdir->d_inode;
|
| 83 | char name[OVL_TEMPNAME_SIZE];
|
| 84 |
|
| 85 | guard(mutex)(&ofs->whiteout_lock);
|
| 86 |
|
| 87 | if (!ofs->whiteout) {
|
| 88 | whiteout = ovl_start_creating_temp(ofs, workdir, name);
|
| 89 | if (IS_ERR(whiteout))
|
| 90 | return whiteout;
|
| 91 | err = ovl_do_whiteout(ofs, wdir, whiteout);
|
| 92 | if (!err)
|
| 93 | ofs->whiteout = dget(whiteout);
|
| 94 | end_creating(whiteout);
|
| 95 | if (err)
|
| 96 | return ERR_PTR(err);
|
| 97 | }
|
| 98 |
|
| 99 | if (!ofs->no_shared_whiteout) {
|
| 100 | link = ovl_start_creating_temp(ofs, workdir, name);
|
| 101 | if (IS_ERR(link))
|
| 102 | return link;
|
| 103 | err = ovl_do_link(ofs, ofs->whiteout, wdir, link);
|
| 104 | if (!err)
|
| 105 | whiteout = dget(link);
|
| 106 | end_creating(link);
|
| 107 | if (!err)
|
| 108 | return whiteout;
|
| 109 |
|
| 110 | if (err != -EMLINK) {
|
| 111 | pr_warn("Failed to link whiteout - disabling whiteout inode sharing(nlink=%u, err=%u)\n",
|
| 112 | ofs->whiteout->d_inode->i_nlink,
|
| 113 | err);
|
| 114 | ofs->no_shared_whiteout = true;
|
| 115 | }
|
| 116 | }
|
| 117 | whiteout = ofs->whiteout;
|
| 118 | ofs->whiteout = NULL;
|
| 119 | return whiteout;
|
| 120 | }
|
| 121 |
|
| 122 | int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct dentry *dir,
|
| 123 | struct dentry *dentry)
|
| 124 | {
|
| 125 | struct dentry *whiteout;
|
| 126 | struct renamedata rd = {};
|
| 127 | int err;
|
| 128 | int flags = 0;
|
| 129 |
|
| 130 | whiteout = ovl_whiteout(ofs);
|
| 131 | err = PTR_ERR(whiteout);
|
| 132 | if (IS_ERR(whiteout))
|
| 133 | return err;
|
| 134 |
|
| 135 | if (d_is_dir(dentry))
|
| 136 | flags = RENAME_EXCHANGE;
|
| 137 |
|
| 138 | rd.mnt_idmap = ovl_upper_mnt_idmap(ofs);
|
| 139 | rd.old_parent = ofs->workdir;
|
| 140 | rd.new_parent = dir;
|
| 141 | rd.flags = flags;
|
| 142 | err = start_renaming_two_dentries(&rd, whiteout, dentry);
|
| 143 | if (!err) {
|
| 144 | err = ovl_do_rename_rd(&rd);
|
| 145 | end_renaming(&rd);
|
| 146 | }
|
| 147 | if (err)
|
| 148 | goto kill_whiteout;
|
| 149 | if (flags)
|
| 150 | ovl_cleanup(ofs, ofs->workdir, dentry);
|
| 151 |
|
| 152 | out:
|
| 153 | dput(whiteout);
|
| 154 | return err;
|
| 155 |
|
| 156 | kill_whiteout:
|
| 157 | ovl_cleanup(ofs, ofs->workdir, whiteout);
|
| 158 | goto out;
|
| 159 | }
|
| 160 |
|
| 161 | struct dentry *ovl_create_real(struct ovl_fs *ofs, struct dentry *parent,
|
| 162 | struct dentry *newdentry, struct qstr *qname,
|
| 163 | struct ovl_cattr *attr)
|
| 164 | {
|
| 165 | struct inode *dir = parent->d_inode;
|
| 166 | int err;
|
| 167 |
|
| 168 | if (IS_ERR(newdentry))
|
| 169 | return newdentry;
|
| 170 |
|
| 171 | err = -ESTALE;
|
| 172 | if (newdentry->d_inode)
|
| 173 | goto out;
|
| 174 |
|
| 175 | if (attr->hardlink) {
|
| 176 | err = ovl_do_link(ofs, attr->hardlink, dir, newdentry);
|
| 177 | } else {
|
| 178 | switch (attr->mode & S_IFMT) {
|
| 179 | case S_IFREG:
|
| 180 | err = ovl_do_create(ofs, dir, newdentry, attr->mode);
|
| 181 | break;
|
| 182 |
|
| 183 | case S_IFDIR:
|
| 184 |
|
| 185 | newdentry = ovl_do_mkdir(ofs, dir, newdentry, attr->mode);
|
| 186 | err = PTR_ERR_OR_ZERO(newdentry);
|
| 187 |
|
| 188 | if (!err && ofs->casefold != ovl_dentry_casefolded(newdentry)) {
|
| 189 | pr_warn_ratelimited("wrong inherited casefold (%pd2)\n",
|
| 190 | newdentry);
|
| 191 | err = -EINVAL;
|
| 192 | }
|
| 193 | break;
|
| 194 |
|
| 195 | case S_IFCHR:
|
| 196 | case S_IFBLK:
|
| 197 | case S_IFIFO:
|
| 198 | case S_IFSOCK:
|
| 199 | err = ovl_do_mknod(ofs, dir, newdentry, attr->mode,
|
| 200 | attr->rdev);
|
| 201 | break;
|
| 202 |
|
| 203 | case S_IFLNK:
|
| 204 | err = ovl_do_symlink(ofs, dir, newdentry, attr->link);
|
| 205 | break;
|
| 206 |
|
| 207 | default:
|
| 208 | err = -EPERM;
|
| 209 | }
|
| 210 | }
|
| 211 | if (err)
|
| 212 | goto out;
|
| 213 |
|
| 214 | if (WARN_ON(!newdentry->d_inode)) {
|
| 215 | |
| 216 | * Not quite sure if non-instantiated dentry is legal or not.
|
| 217 | * VFS doesn't seem to care so check and warn here.
|
| 218 |
|
| 219 | err = -EIO;
|
| 220 | } else if (d_unhashed(newdentry)) {
|
| 221 | struct dentry *d;
|
| 222 | |
| 223 | * Some filesystems (i.e. casefolded) may return an unhashed
|
| 224 | * negative dentry from the ovl_start_creating_upper() call before
|
| 225 | * ovl_create_real().
|
| 226 | * In that case, lookup again after making the newdentry
|
| 227 | * positive, so ovl_create_upper() always returns a hashed
|
| 228 | * positive dentry. We lookup using qname which should be
|
| 229 | * the same name as newentry, but is certain not to change.
|
| 230 | * As we have to drop the lock before the lookup a race
|
| 231 | * could result in a lookup failure. In that case we return
|
| 232 | * an error.
|
| 233 |
|
| 234 | end_creating_keep(newdentry);
|
| 235 | d = ovl_start_creating_upper(ofs, parent, qname);
|
| 236 |
|
| 237 | if (IS_ERR_OR_NULL(d)) {
|
| 238 | err = d ? PTR_ERR(d) : -ENOENT;
|
| 239 | } else if (d->d_inode != newdentry->d_inode) {
|
| 240 | err = -EIO;
|
| 241 | } else {
|
| 242 | dput(newdentry);
|
| 243 | return d;
|
| 244 | }
|
| 245 | end_creating(d);
|
| 246 | dput(newdentry);
|
| 247 | return ERR_PTR(err);
|
| 248 | }
|
| 249 | out:
|
| 250 | if (err) {
|
| 251 | end_creating(newdentry);
|
| 252 | return ERR_PTR(err);
|
| 253 | }
|
| 254 | return newdentry;
|
| 255 | }
|
| 256 |
|
| 257 | struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
|
| 258 | struct ovl_cattr *attr)
|
| 259 | {
|
| 260 | struct dentry *ret;
|
| 261 | char name[OVL_TEMPNAME_SIZE];
|
| 262 |
|
| 263 | ret = ovl_start_creating_temp(ofs, workdir, name);
|
| 264 | if (IS_ERR(ret))
|
| 265 | return ret;
|
| 266 | ret = ovl_create_real(ofs, workdir, ret, &QSTR(name), attr);
|
| 267 | return end_creating_keep(ret);
|
| 268 | }
|
| 269 |
|
| 270 | static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper,
|
| 271 | int xerr)
|
| 272 | {
|
| 273 | struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
|
| 274 | int err;
|
| 275 |
|
| 276 | err = ovl_check_setxattr(ofs, upper, OVL_XATTR_OPAQUE, "y", 1, xerr);
|
| 277 | if (!err)
|
| 278 | ovl_dentry_set_opaque(dentry);
|
| 279 |
|
| 280 | return err;
|
| 281 | }
|
| 282 |
|
| 283 | static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
|
| 284 | {
|
| 285 | |
| 286 | * Fail with -EIO when trying to create opaque dir and upper doesn't
|
| 287 | * support xattrs. ovl_rename() calls ovl_set_opaque_xerr(-EXDEV) to
|
| 288 | * return a specific error for noxattr case.
|
| 289 |
|
| 290 | return ovl_set_opaque_xerr(dentry, upperdentry, -EIO);
|
| 291 | }
|
| 292 |
|
| 293 | |
| 294 | * Common operations required to be done after creation of file on upper.
|
| 295 | * If @hardlink is false, then @inode is a pre-allocated inode, we may or
|
| 296 | * may not use to instantiate the new dentry.
|
| 297 |
|
| 298 | static int ovl_instantiate(struct dentry *dentry, struct inode *inode,
|
| 299 | struct dentry *newdentry, bool hardlink, struct file *tmpfile)
|
| 300 | {
|
| 301 | struct ovl_inode_params oip = {
|
| 302 | .upperdentry = newdentry,
|
| 303 | .newinode = inode,
|
| 304 | };
|
| 305 |
|
| 306 | ovl_dentry_set_upper_alias(dentry);
|
| 307 | ovl_dentry_init_reval(dentry, newdentry, NULL);
|
| 308 |
|
| 309 | if (!hardlink) {
|
| 310 | |
| 311 | * ovl_obtain_alias() can be called after ovl_create_real()
|
| 312 | * and before we get here, so we may get an inode from cache
|
| 313 | * with the same real upperdentry that is not the inode we
|
| 314 | * pre-allocated. In this case we will use the cached inode
|
| 315 | * to instantiate the new dentry.
|
| 316 | *
|
| 317 | * XXX: if we ever use ovl_obtain_alias() to decode directory
|
| 318 | * file handles, need to use ovl_get_inode_locked() and
|
| 319 | * d_instantiate_new() here to prevent from creating two
|
| 320 | * hashed directory inode aliases. We then need to return
|
| 321 | * the obtained alias to ovl_mkdir().
|
| 322 |
|
| 323 | inode = ovl_get_inode(dentry->d_sb, &oip);
|
| 324 | if (IS_ERR(inode))
|
| 325 | return PTR_ERR(inode);
|
| 326 | if (inode == oip.newinode)
|
| 327 | ovl_set_flag(OVL_UPPERDATA, inode);
|
| 328 | } else {
|
| 329 | WARN_ON(ovl_inode_real(inode) != d_inode(newdentry));
|
| 330 | dput(newdentry);
|
| 331 | inc_nlink(inode);
|
| 332 | }
|
| 333 |
|
| 334 | if (tmpfile)
|
| 335 | d_mark_tmpfile(tmpfile, inode);
|
| 336 |
|
| 337 | d_instantiate(dentry, inode);
|
| 338 | if (inode != oip.newinode) {
|
| 339 | pr_warn_ratelimited("newly created inode found in cache (%pd2)\n",
|
| 340 | dentry);
|
| 341 | }
|
| 342 |
|
| 343 |
|
| 344 | if (hardlink)
|
| 345 | d_drop(dentry);
|
| 346 |
|
| 347 | return 0;
|
| 348 | }
|
| 349 |
|
| 350 | static bool ovl_type_merge(struct dentry *dentry)
|
| 351 | {
|
| 352 | return OVL_TYPE_MERGE(ovl_path_type(dentry));
|
| 353 | }
|
| 354 |
|
| 355 | static bool ovl_type_origin(struct dentry *dentry)
|
| 356 | {
|
| 357 | return OVL_TYPE_ORIGIN(ovl_path_type(dentry));
|
| 358 | }
|
| 359 |
|
| 360 | static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
|
| 361 | struct ovl_cattr *attr)
|
| 362 | {
|
| 363 | struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
|
| 364 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
|
| 365 | struct dentry *newdentry;
|
| 366 | struct qstr qname = QSTR_LEN(dentry->d_name.name,
|
| 367 | dentry->d_name.len);
|
| 368 | int err;
|
| 369 |
|
| 370 | newdentry = ovl_start_creating_upper(ofs, upperdir,
|
| 371 | &qname);
|
| 372 | if (IS_ERR(newdentry))
|
| 373 | return PTR_ERR(newdentry);
|
| 374 | newdentry = ovl_create_real(ofs, upperdir, newdentry, &qname, attr);
|
| 375 | if (IS_ERR(newdentry))
|
| 376 | return PTR_ERR(newdentry);
|
| 377 |
|
| 378 | end_creating_keep(newdentry);
|
| 379 |
|
| 380 | if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry) &&
|
| 381 | !ovl_allow_offline_changes(ofs)) {
|
| 382 |
|
| 383 | ovl_set_opaque(dentry, newdentry);
|
| 384 | }
|
| 385 |
|
| 386 | ovl_dir_modified(dentry->d_parent, false);
|
| 387 | err = ovl_instantiate(dentry, inode, newdentry, !!attr->hardlink, NULL);
|
| 388 | if (err)
|
| 389 | goto out_cleanup;
|
| 390 | return 0;
|
| 391 |
|
| 392 | out_cleanup:
|
| 393 | ovl_cleanup(ofs, upperdir, newdentry);
|
| 394 | dput(newdentry);
|
| 395 | return err;
|
| 396 | }
|
| 397 |
|
| 398 | static struct dentry *ovl_clear_empty(struct dentry *dentry,
|
| 399 | struct list_head *list)
|
| 400 | {
|
| 401 | struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
|
| 402 | struct dentry *workdir = ovl_workdir(dentry);
|
| 403 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
|
| 404 | struct renamedata rd = {};
|
| 405 | struct path upperpath;
|
| 406 | struct dentry *upper;
|
| 407 | struct dentry *opaquedir;
|
| 408 | struct kstat stat;
|
| 409 | int err;
|
| 410 |
|
| 411 | if (WARN_ON(!workdir))
|
| 412 | return ERR_PTR(-EROFS);
|
| 413 |
|
| 414 | ovl_path_upper(dentry, &upperpath);
|
| 415 | err = vfs_getattr(&upperpath, &stat,
|
| 416 | STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
|
| 417 | if (err)
|
| 418 | goto out;
|
| 419 |
|
| 420 | err = -ESTALE;
|
| 421 | if (!S_ISDIR(stat.mode))
|
| 422 | goto out;
|
| 423 | upper = upperpath.dentry;
|
| 424 |
|
| 425 | opaquedir = ovl_create_temp(ofs, workdir, OVL_CATTR(stat.mode));
|
| 426 | err = PTR_ERR(opaquedir);
|
| 427 | if (IS_ERR(opaquedir))
|
| 428 | goto out;
|
| 429 |
|
| 430 | rd.mnt_idmap = ovl_upper_mnt_idmap(ofs);
|
| 431 | rd.old_parent = workdir;
|
| 432 | rd.new_parent = upperdir;
|
| 433 | rd.flags = RENAME_EXCHANGE;
|
| 434 | err = start_renaming_two_dentries(&rd, opaquedir, upper);
|
| 435 | if (err)
|
| 436 | goto out_cleanup_unlocked;
|
| 437 |
|
| 438 | err = ovl_copy_xattr(dentry->d_sb, &upperpath, opaquedir);
|
| 439 | if (err)
|
| 440 | goto out_cleanup;
|
| 441 |
|
| 442 | err = ovl_set_opaque(dentry, opaquedir);
|
| 443 | if (err)
|
| 444 | goto out_cleanup;
|
| 445 |
|
| 446 | inode_lock(opaquedir->d_inode);
|
| 447 | err = ovl_set_attr(ofs, opaquedir, &stat);
|
| 448 | inode_unlock(opaquedir->d_inode);
|
| 449 | if (err)
|
| 450 | goto out_cleanup;
|
| 451 |
|
| 452 | err = ovl_do_rename_rd(&rd);
|
| 453 | end_renaming(&rd);
|
| 454 | if (err)
|
| 455 | goto out_cleanup_unlocked;
|
| 456 |
|
| 457 | ovl_cleanup_whiteouts(ofs, upper, list);
|
| 458 | ovl_cleanup(ofs, workdir, upper);
|
| 459 |
|
| 460 |
|
| 461 | d_drop(dentry);
|
| 462 |
|
| 463 | return opaquedir;
|
| 464 |
|
| 465 | out_cleanup:
|
| 466 | end_renaming(&rd);
|
| 467 | out_cleanup_unlocked:
|
| 468 | ovl_cleanup(ofs, workdir, opaquedir);
|
| 469 | dput(opaquedir);
|
| 470 | out:
|
| 471 | return ERR_PTR(err);
|
| 472 | }
|
| 473 |
|
| 474 | static int ovl_set_upper_acl(struct ovl_fs *ofs, struct dentry *upperdentry,
|
| 475 | const char *acl_name, struct posix_acl *acl)
|
| 476 | {
|
| 477 | if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl)
|
| 478 | return 0;
|
| 479 |
|
| 480 | return ovl_do_set_acl(ofs, upperdentry, acl_name, acl);
|
| 481 | }
|
| 482 |
|
| 483 | static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
|
| 484 | struct ovl_cattr *cattr)
|
| 485 | {
|
| 486 | struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
|
| 487 | struct dentry *workdir = ovl_workdir(dentry);
|
| 488 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
|
| 489 | struct renamedata rd = {};
|
| 490 | struct dentry *upper;
|
| 491 | struct dentry *newdentry;
|
| 492 | int err;
|
| 493 | struct posix_acl *acl, *default_acl;
|
| 494 | bool hardlink = !!cattr->hardlink;
|
| 495 |
|
| 496 | if (WARN_ON(!workdir))
|
| 497 | return -EROFS;
|
| 498 |
|
| 499 | if (!hardlink) {
|
| 500 | err = posix_acl_create(dentry->d_parent->d_inode,
|
| 501 | &cattr->mode, &default_acl, &acl);
|
| 502 | if (err)
|
| 503 | return err;
|
| 504 | }
|
| 505 |
|
| 506 | upper = ovl_lookup_upper_unlocked(ofs, dentry->d_name.name, upperdir,
|
| 507 | dentry->d_name.len);
|
| 508 | err = PTR_ERR(upper);
|
| 509 | if (IS_ERR(upper))
|
| 510 | goto out;
|
| 511 |
|
| 512 | err = -ESTALE;
|
| 513 | if (d_is_negative(upper) || !ovl_upper_is_whiteout(ofs, upper))
|
| 514 | goto out_dput;
|
| 515 |
|
| 516 | newdentry = ovl_create_temp(ofs, workdir, cattr);
|
| 517 | err = PTR_ERR(newdentry);
|
| 518 | if (IS_ERR(newdentry))
|
| 519 | goto out_dput;
|
| 520 |
|
| 521 | rd.mnt_idmap = ovl_upper_mnt_idmap(ofs);
|
| 522 | rd.old_parent = workdir;
|
| 523 | rd.new_parent = upperdir;
|
| 524 | rd.flags = 0;
|
| 525 | err = start_renaming_two_dentries(&rd, newdentry, upper);
|
| 526 | if (err)
|
| 527 | goto out_cleanup_unlocked;
|
| 528 |
|
| 529 | |
| 530 | * mode could have been mutilated due to umask (e.g. sgid directory)
|
| 531 |
|
| 532 | if (!hardlink &&
|
| 533 | !S_ISLNK(cattr->mode) &&
|
| 534 | newdentry->d_inode->i_mode != cattr->mode) {
|
| 535 | struct iattr attr = {
|
| 536 | .ia_valid = ATTR_MODE,
|
| 537 | .ia_mode = cattr->mode,
|
| 538 | };
|
| 539 | inode_lock(newdentry->d_inode);
|
| 540 | err = ovl_do_notify_change(ofs, newdentry, &attr);
|
| 541 | inode_unlock(newdentry->d_inode);
|
| 542 | if (err)
|
| 543 | goto out_cleanup;
|
| 544 | }
|
| 545 | if (!hardlink) {
|
| 546 | err = ovl_set_upper_acl(ofs, newdentry,
|
| 547 | XATTR_NAME_POSIX_ACL_ACCESS, acl);
|
| 548 | if (err)
|
| 549 | goto out_cleanup;
|
| 550 |
|
| 551 | err = ovl_set_upper_acl(ofs, newdentry,
|
| 552 | XATTR_NAME_POSIX_ACL_DEFAULT, default_acl);
|
| 553 | if (err)
|
| 554 | goto out_cleanup;
|
| 555 | }
|
| 556 |
|
| 557 | if (!hardlink && S_ISDIR(cattr->mode)) {
|
| 558 | err = ovl_set_opaque(dentry, newdentry);
|
| 559 | if (err)
|
| 560 | goto out_cleanup;
|
| 561 |
|
| 562 | rd.flags = RENAME_EXCHANGE;
|
| 563 | err = ovl_do_rename_rd(&rd);
|
| 564 | end_renaming(&rd);
|
| 565 | if (err)
|
| 566 | goto out_cleanup_unlocked;
|
| 567 |
|
| 568 | ovl_cleanup(ofs, workdir, upper);
|
| 569 | } else {
|
| 570 | err = ovl_do_rename_rd(&rd);
|
| 571 | end_renaming(&rd);
|
| 572 | if (err)
|
| 573 | goto out_cleanup_unlocked;
|
| 574 | }
|
| 575 | ovl_dir_modified(dentry->d_parent, false);
|
| 576 | err = ovl_instantiate(dentry, inode, newdentry, hardlink, NULL);
|
| 577 | if (err) {
|
| 578 | ovl_cleanup(ofs, upperdir, newdentry);
|
| 579 | dput(newdentry);
|
| 580 | }
|
| 581 | out_dput:
|
| 582 | dput(upper);
|
| 583 | out:
|
| 584 | if (!hardlink) {
|
| 585 | posix_acl_release(acl);
|
| 586 | posix_acl_release(default_acl);
|
| 587 | }
|
| 588 | return err;
|
| 589 |
|
| 590 | out_cleanup:
|
| 591 | end_renaming(&rd);
|
| 592 | out_cleanup_unlocked:
|
| 593 | ovl_cleanup(ofs, workdir, newdentry);
|
| 594 | dput(newdentry);
|
| 595 | goto out_dput;
|
| 596 | }
|
| 597 |
|
| 598 | static const struct cred *ovl_override_creator_creds(const struct cred *original_creds,
|
| 599 | struct dentry *dentry, struct inode *inode, umode_t mode)
|
| 600 | {
|
| 601 | int err;
|
| 602 |
|
| 603 | if (WARN_ON_ONCE(current->cred != ovl_creds(dentry->d_sb)))
|
| 604 | return ERR_PTR(-EINVAL);
|
| 605 |
|
| 606 | CLASS(prepare_creds, override_cred)();
|
| 607 | if (!override_cred)
|
| 608 | return ERR_PTR(-ENOMEM);
|
| 609 |
|
| 610 | override_cred->fsuid = inode->i_uid;
|
| 611 | override_cred->fsgid = inode->i_gid;
|
| 612 |
|
| 613 | err = security_dentry_create_files_as(dentry, mode, &dentry->d_name,
|
| 614 | original_creds, override_cred);
|
| 615 | if (err)
|
| 616 | return ERR_PTR(err);
|
| 617 |
|
| 618 | return override_creds(no_free_ptr(override_cred));
|
| 619 | }
|
| 620 |
|
| 621 | static void ovl_revert_creator_creds(const struct cred *old_cred)
|
| 622 | {
|
| 623 | const struct cred *override_cred;
|
| 624 |
|
| 625 | override_cred = revert_creds(old_cred);
|
| 626 | put_cred(override_cred);
|
| 627 | }
|
| 628 |
|
| 629 | DEFINE_CLASS(ovl_override_creator_creds,
|
| 630 | const struct cred *,
|
| 631 | if (!IS_ERR_OR_NULL(_T)) ovl_revert_creator_creds(_T),
|
| 632 | ovl_override_creator_creds(original_creds, dentry, inode, mode),
|
| 633 | const struct cred *original_creds,
|
| 634 | struct dentry *dentry,
|
| 635 | struct inode *inode,
|
| 636 | umode_t mode)
|
| 637 |
|
| 638 | static int ovl_create_handle_whiteouts(struct dentry *dentry,
|
| 639 | struct inode *inode,
|
| 640 | struct ovl_cattr *attr)
|
| 641 | {
|
| 642 | if (!ovl_dentry_is_whiteout(dentry))
|
| 643 | return ovl_create_upper(dentry, inode, attr);
|
| 644 |
|
| 645 | return ovl_create_over_whiteout(dentry, inode, attr);
|
| 646 | }
|
| 647 |
|
| 648 | static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
|
| 649 | struct ovl_cattr *attr, bool origin)
|
| 650 | {
|
| 651 | int err;
|
| 652 | struct dentry *parent = dentry->d_parent;
|
| 653 |
|
| 654 | scoped_class(override_creds_ovl, original_creds, dentry->d_sb) {
|
| 655 | |
| 656 | * When linking a file with copy up origin into a new parent, mark the
|
| 657 | * new parent dir "impure".
|
| 658 |
|
| 659 | if (origin) {
|
| 660 | err = ovl_set_impure(parent, ovl_dentry_upper(parent));
|
| 661 | if (err)
|
| 662 | return err;
|
| 663 | }
|
| 664 |
|
| 665 | |
| 666 | * In the creation cases(create, mkdir, mknod, symlink),
|
| 667 | * ovl should transfer current's fs{u,g}id to underlying
|
| 668 | * fs. Because underlying fs want to initialize its new
|
| 669 | * inode owner using current's fs{u,g}id. And in this
|
| 670 | * case, the @inode is a new inode that is initialized
|
| 671 | * in inode_init_owner() to current's fs{u,g}id. So use
|
| 672 | * the inode's i_{u,g}id to override the cred's fs{u,g}id.
|
| 673 | *
|
| 674 | * But in the other hardlink case, ovl_link() does not
|
| 675 | * create a new inode, so just use the ovl mounter's
|
| 676 | * fs{u,g}id.
|
| 677 |
|
| 678 |
|
| 679 | if (attr->hardlink)
|
| 680 | return ovl_create_handle_whiteouts(dentry, inode, attr);
|
| 681 |
|
| 682 | scoped_class(ovl_override_creator_creds, cred, original_creds, dentry, inode, attr->mode) {
|
| 683 | if (IS_ERR(cred))
|
| 684 | return PTR_ERR(cred);
|
| 685 | return ovl_create_handle_whiteouts(dentry, inode, attr);
|
| 686 | }
|
| 687 | }
|
| 688 | return err;
|
| 689 | }
|
| 690 |
|
| 691 | static int ovl_create_object(const struct mnt_idmap *idmap, struct dentry *dentry,
|
| 692 | int mode, dev_t rdev, const char *link)
|
| 693 | {
|
| 694 | int err;
|
| 695 | struct inode *inode;
|
| 696 | struct ovl_cattr attr = {
|
| 697 | .rdev = rdev,
|
| 698 | .link = link,
|
| 699 | };
|
| 700 |
|
| 701 | err = ovl_copy_up(dentry->d_parent);
|
| 702 | if (err)
|
| 703 | return err;
|
| 704 |
|
| 705 | err = ovl_want_write(dentry);
|
| 706 | if (err)
|
| 707 | goto out;
|
| 708 |
|
| 709 |
|
| 710 | err = -ENOMEM;
|
| 711 | inode = ovl_new_inode(dentry->d_sb, mode, rdev);
|
| 712 | if (!inode)
|
| 713 | goto out_drop_write;
|
| 714 |
|
| 715 | spin_lock(&inode->i_lock);
|
| 716 | inode_state_set(inode, I_CREATING);
|
| 717 | spin_unlock(&inode->i_lock);
|
| 718 |
|
| 719 | inode_init_owner(idmap, inode, dentry->d_parent->d_inode, mode);
|
| 720 | attr.mode = inode->i_mode;
|
| 721 |
|
| 722 | err = ovl_create_or_link(dentry, inode, &attr, false);
|
| 723 |
|
| 724 | if (inode != d_inode(dentry))
|
| 725 | iput(inode);
|
| 726 |
|
| 727 | out_drop_write:
|
| 728 | ovl_drop_write(dentry);
|
| 729 | out:
|
| 730 | return err;
|
| 731 | }
|
| 732 |
|
| 733 | static int ovl_create(const struct mnt_idmap *idmap, struct inode *dir,
|
| 734 | struct dentry *dentry, umode_t mode)
|
| 735 | {
|
| 736 | return ovl_create_object(idmap, dentry, (mode & 07777) | S_IFREG, 0, NULL);
|
| 737 | }
|
| 738 |
|
| 739 | static struct dentry *ovl_mkdir(const struct mnt_idmap *idmap, struct inode *dir,
|
| 740 | struct dentry *dentry, umode_t mode)
|
| 741 | {
|
| 742 | return ERR_PTR(ovl_create_object(idmap, dentry, (mode & 07777) | S_IFDIR, 0, NULL));
|
| 743 | }
|
| 744 |
|
| 745 | static int ovl_mknod(const struct mnt_idmap *idmap, struct inode *dir,
|
| 746 | struct dentry *dentry, umode_t mode, dev_t rdev)
|
| 747 | {
|
| 748 |
|
| 749 | if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
|
| 750 | return -EPERM;
|
| 751 |
|
| 752 | return ovl_create_object(idmap, dentry, mode, rdev, NULL);
|
| 753 | }
|
| 754 |
|
| 755 | static int ovl_symlink(const struct mnt_idmap *idmap, struct inode *dir,
|
| 756 | struct dentry *dentry, const char *link)
|
| 757 | {
|
| 758 | return ovl_create_object(idmap, dentry, S_IFLNK, 0, link);
|
| 759 | }
|
| 760 |
|
| 761 | static int ovl_set_link_redirect(struct dentry *dentry)
|
| 762 | {
|
| 763 | with_ovl_creds(dentry->d_sb)
|
| 764 | return ovl_set_redirect(dentry, false);
|
| 765 | }
|
| 766 |
|
| 767 | static int ovl_link(struct dentry *old, struct inode *newdir,
|
| 768 | struct dentry *new)
|
| 769 | {
|
| 770 | int err;
|
| 771 | struct inode *inode;
|
| 772 |
|
| 773 | err = ovl_copy_up(old);
|
| 774 | if (err)
|
| 775 | goto out;
|
| 776 |
|
| 777 | err = ovl_copy_up(new->d_parent);
|
| 778 | if (err)
|
| 779 | goto out;
|
| 780 |
|
| 781 | err = ovl_nlink_start(old);
|
| 782 | if (err)
|
| 783 | goto out;
|
| 784 |
|
| 785 | if (ovl_is_metacopy_dentry(old)) {
|
| 786 | err = ovl_set_link_redirect(old);
|
| 787 | if (err)
|
| 788 | goto out_nlink_end;
|
| 789 | }
|
| 790 |
|
| 791 | inode = d_inode(old);
|
| 792 | ihold(inode);
|
| 793 |
|
| 794 | err = ovl_create_or_link(new, inode,
|
| 795 | &(struct ovl_cattr) {.hardlink = ovl_dentry_upper(old)},
|
| 796 | ovl_type_origin(old));
|
| 797 | if (err)
|
| 798 | iput(inode);
|
| 799 |
|
| 800 | out_nlink_end:
|
| 801 | ovl_nlink_end(old);
|
| 802 | out:
|
| 803 | return err;
|
| 804 | }
|
| 805 |
|
| 806 | static bool ovl_matches_upper(struct dentry *dentry, struct dentry *upper)
|
| 807 | {
|
| 808 | return d_inode(ovl_dentry_upper(dentry)) == d_inode(upper);
|
| 809 | }
|
| 810 |
|
| 811 | static int ovl_remove_and_whiteout(struct dentry *dentry,
|
| 812 | struct list_head *list)
|
| 813 | {
|
| 814 | struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
|
| 815 | struct dentry *workdir = ovl_workdir(dentry);
|
| 816 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
|
| 817 | struct dentry *upper;
|
| 818 | struct dentry *opaquedir = NULL;
|
| 819 | int err;
|
| 820 |
|
| 821 | if (WARN_ON(!workdir))
|
| 822 | return -EROFS;
|
| 823 |
|
| 824 | if (!list_empty(list)) {
|
| 825 | opaquedir = ovl_clear_empty(dentry, list);
|
| 826 | err = PTR_ERR(opaquedir);
|
| 827 | if (IS_ERR(opaquedir))
|
| 828 | goto out;
|
| 829 | }
|
| 830 |
|
| 831 | upper = ovl_lookup_upper_unlocked(ofs, dentry->d_name.name, upperdir,
|
| 832 | dentry->d_name.len);
|
| 833 | err = PTR_ERR(upper);
|
| 834 | if (IS_ERR(upper))
|
| 835 | goto out_dput;
|
| 836 |
|
| 837 | err = -ESTALE;
|
| 838 | if ((opaquedir && upper != opaquedir) ||
|
| 839 | (!opaquedir && ovl_dentry_upper(dentry) &&
|
| 840 | !ovl_matches_upper(dentry, upper))) {
|
| 841 | goto out_dput_upper;
|
| 842 | }
|
| 843 |
|
| 844 | err = ovl_cleanup_and_whiteout(ofs, upperdir, upper);
|
| 845 | if (!err)
|
| 846 | ovl_dir_modified(dentry->d_parent, true);
|
| 847 |
|
| 848 | d_drop(dentry);
|
| 849 | out_dput_upper:
|
| 850 | dput(upper);
|
| 851 | out_dput:
|
| 852 | dput(opaquedir);
|
| 853 | out:
|
| 854 | return err;
|
| 855 | }
|
| 856 |
|
| 857 | static int ovl_remove_upper(struct dentry *dentry, bool is_dir,
|
| 858 | struct list_head *list)
|
| 859 | {
|
| 860 | struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
|
| 861 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
|
| 862 | struct inode *dir = upperdir->d_inode;
|
| 863 | struct dentry *upper;
|
| 864 | struct dentry *opaquedir = NULL;
|
| 865 | int err;
|
| 866 |
|
| 867 | if (!list_empty(list)) {
|
| 868 | opaquedir = ovl_clear_empty(dentry, list);
|
| 869 | err = PTR_ERR(opaquedir);
|
| 870 | if (IS_ERR(opaquedir))
|
| 871 | goto out;
|
| 872 | }
|
| 873 |
|
| 874 | upper = ovl_start_removing_upper(ofs, upperdir,
|
| 875 | &QSTR_LEN(dentry->d_name.name,
|
| 876 | dentry->d_name.len));
|
| 877 | err = PTR_ERR(upper);
|
| 878 | if (IS_ERR(upper))
|
| 879 | goto out_dput;
|
| 880 |
|
| 881 | err = -ESTALE;
|
| 882 | if ((opaquedir && upper != opaquedir) ||
|
| 883 | (!opaquedir && !ovl_matches_upper(dentry, upper)))
|
| 884 | goto out_unlock;
|
| 885 |
|
| 886 | if (is_dir)
|
| 887 | err = ovl_do_rmdir(ofs, dir, upper);
|
| 888 | else
|
| 889 | err = ovl_do_unlink(ofs, dir, upper);
|
| 890 | ovl_dir_modified(dentry->d_parent, ovl_type_origin(dentry));
|
| 891 |
|
| 892 | |
| 893 | * Keeping this dentry hashed would mean having to release
|
| 894 | * upperpath/lowerpath, which could only be done if we are the
|
| 895 | * sole user of this dentry. Too tricky... Just unhash for
|
| 896 | * now.
|
| 897 |
|
| 898 | if (!err)
|
| 899 | d_drop(dentry);
|
| 900 | out_unlock:
|
| 901 | end_removing(upper);
|
| 902 | out_dput:
|
| 903 | dput(opaquedir);
|
| 904 | out:
|
| 905 | return err;
|
| 906 | }
|
| 907 |
|
| 908 | static bool ovl_pure_upper(struct dentry *dentry)
|
| 909 | {
|
| 910 | return !ovl_dentry_lower(dentry) &&
|
| 911 | !ovl_test_flag(OVL_WHITEOUTS, d_inode(dentry));
|
| 912 | }
|
| 913 |
|
| 914 | static void ovl_drop_nlink(struct dentry *dentry)
|
| 915 | {
|
| 916 | struct inode *inode = d_inode(dentry);
|
| 917 | struct dentry *alias;
|
| 918 |
|
| 919 |
|
| 920 | spin_lock(&inode->i_lock);
|
| 921 | for_each_alias(alias, inode) {
|
| 922 | if (alias != dentry && !d_unhashed(alias))
|
| 923 | break;
|
| 924 | }
|
| 925 | spin_unlock(&inode->i_lock);
|
| 926 |
|
| 927 | |
| 928 | * Changes to underlying layers may cause i_nlink to lose sync with
|
| 929 | * reality. In this case prevent the link count from going to zero
|
| 930 | * prematurely.
|
| 931 |
|
| 932 | if (inode->i_nlink > !!alias)
|
| 933 | drop_nlink(inode);
|
| 934 | }
|
| 935 |
|
| 936 | static int ovl_do_remove(struct dentry *dentry, bool is_dir)
|
| 937 | {
|
| 938 | int err;
|
| 939 | bool lower_positive = ovl_lower_positive(dentry);
|
| 940 | LIST_HEAD(list);
|
| 941 |
|
| 942 |
|
| 943 | if (is_dir && (lower_positive || !ovl_pure_upper(dentry))) {
|
| 944 | err = ovl_check_empty_dir(dentry, &list);
|
| 945 | if (err)
|
| 946 | goto out;
|
| 947 | }
|
| 948 |
|
| 949 | err = ovl_copy_up(dentry->d_parent);
|
| 950 | if (err)
|
| 951 | goto out;
|
| 952 |
|
| 953 | err = ovl_nlink_start(dentry);
|
| 954 | if (err)
|
| 955 | goto out;
|
| 956 |
|
| 957 | with_ovl_creds(dentry->d_sb) {
|
| 958 | if (!lower_positive)
|
| 959 | err = ovl_remove_upper(dentry, is_dir, &list);
|
| 960 | else
|
| 961 | err = ovl_remove_and_whiteout(dentry, &list);
|
| 962 | }
|
| 963 | if (!err) {
|
| 964 | if (is_dir)
|
| 965 | clear_nlink(dentry->d_inode);
|
| 966 | else
|
| 967 | ovl_drop_nlink(dentry);
|
| 968 | }
|
| 969 | ovl_nlink_end(dentry);
|
| 970 |
|
| 971 | |
| 972 | * Copy ctime
|
| 973 | *
|
| 974 | * Note: we fail to update ctime if there was no copy-up, only a
|
| 975 | * whiteout
|
| 976 |
|
| 977 | if (ovl_dentry_upper(dentry))
|
| 978 | ovl_copyattr(d_inode(dentry));
|
| 979 |
|
| 980 | out:
|
| 981 | ovl_cache_free(&list);
|
| 982 | return err;
|
| 983 | }
|
| 984 |
|
| 985 | static int ovl_unlink(struct inode *dir, struct dentry *dentry)
|
| 986 | {
|
| 987 | return ovl_do_remove(dentry, false);
|
| 988 | }
|
| 989 |
|
| 990 | static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
|
| 991 | {
|
| 992 | return ovl_do_remove(dentry, true);
|
| 993 | }
|
| 994 |
|
| 995 | static bool ovl_type_merge_or_lower(struct dentry *dentry)
|
| 996 | {
|
| 997 | enum ovl_path_type type = ovl_path_type(dentry);
|
| 998 |
|
| 999 | return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type);
|
| 1000 | }
|
| 1001 |
|
| 1002 | static bool ovl_can_move(struct dentry *dentry)
|
| 1003 | {
|
| 1004 | return ovl_redirect_dir(OVL_FS(dentry->d_sb)) ||
|
| 1005 | !d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry);
|
| 1006 | }
|
| 1007 |
|
| 1008 | static char *ovl_get_redirect(struct dentry *dentry, bool abs_redirect)
|
| 1009 | {
|
| 1010 | char *buf, *ret;
|
| 1011 | struct dentry *d, *tmp;
|
| 1012 | int buflen = ovl_redirect_max + 1;
|
| 1013 |
|
| 1014 | if (!abs_redirect) {
|
| 1015 | ret = kstrndup(dentry->d_name.name, dentry->d_name.len,
|
| 1016 | GFP_KERNEL);
|
| 1017 | goto out;
|
| 1018 | }
|
| 1019 |
|
| 1020 | buf = ret = kmalloc(buflen, GFP_KERNEL);
|
| 1021 | if (!buf)
|
| 1022 | goto out;
|
| 1023 |
|
| 1024 | buflen--;
|
| 1025 | buf[buflen] = '\0';
|
| 1026 | for (d = dget(dentry); !IS_ROOT(d);) {
|
| 1027 | const char *name;
|
| 1028 | int thislen;
|
| 1029 |
|
| 1030 | spin_lock(&d->d_lock);
|
| 1031 | name = ovl_dentry_get_redirect(d);
|
| 1032 | if (name) {
|
| 1033 | thislen = strlen(name);
|
| 1034 | } else {
|
| 1035 | name = d->d_name.name;
|
| 1036 | thislen = d->d_name.len;
|
| 1037 | }
|
| 1038 |
|
| 1039 |
|
| 1040 | if (thislen + (name[0] != '/') > buflen) {
|
| 1041 | ret = ERR_PTR(-EXDEV);
|
| 1042 | spin_unlock(&d->d_lock);
|
| 1043 | goto out_put;
|
| 1044 | }
|
| 1045 |
|
| 1046 | buflen -= thislen;
|
| 1047 | memcpy(&buf[buflen], name, thislen);
|
| 1048 | spin_unlock(&d->d_lock);
|
| 1049 | tmp = dget_parent(d);
|
| 1050 |
|
| 1051 | dput(d);
|
| 1052 | d = tmp;
|
| 1053 |
|
| 1054 |
|
| 1055 | if (buf[buflen] == '/')
|
| 1056 | break;
|
| 1057 | buflen--;
|
| 1058 | buf[buflen] = '/';
|
| 1059 | }
|
| 1060 | ret = kstrdup(&buf[buflen], GFP_KERNEL);
|
| 1061 | out_put:
|
| 1062 | dput(d);
|
| 1063 | kfree(buf);
|
| 1064 | out:
|
| 1065 | return ret ? ret : ERR_PTR(-ENOMEM);
|
| 1066 | }
|
| 1067 |
|
| 1068 | static bool ovl_need_absolute_redirect(struct dentry *dentry, bool samedir)
|
| 1069 | {
|
| 1070 | struct dentry *lowerdentry;
|
| 1071 |
|
| 1072 | if (!samedir)
|
| 1073 | return true;
|
| 1074 |
|
| 1075 | if (d_is_dir(dentry))
|
| 1076 | return false;
|
| 1077 |
|
| 1078 | |
| 1079 | * For non-dir hardlinked files, we need absolute redirects
|
| 1080 | * in general as two upper hardlinks could be in different
|
| 1081 | * dirs. We could put a relative redirect now and convert
|
| 1082 | * it to absolute redirect later. But when nlink > 1 and
|
| 1083 | * indexing is on, that means relative redirect needs to be
|
| 1084 | * converted to absolute during copy up of another lower
|
| 1085 | * hardllink as well.
|
| 1086 | *
|
| 1087 | * So without optimizing too much, just check if lower is
|
| 1088 | * a hard link or not. If lower is hard link, put absolute
|
| 1089 | * redirect.
|
| 1090 |
|
| 1091 | lowerdentry = ovl_dentry_lower(dentry);
|
| 1092 | return (d_inode(lowerdentry)->i_nlink > 1);
|
| 1093 | }
|
| 1094 |
|
| 1095 | static int ovl_set_redirect(struct dentry *dentry, bool samedir)
|
| 1096 | {
|
| 1097 | int err;
|
| 1098 | struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
|
| 1099 | const char *redirect = ovl_dentry_get_redirect(dentry);
|
| 1100 | bool absolute_redirect = ovl_need_absolute_redirect(dentry, samedir);
|
| 1101 |
|
| 1102 | if (redirect && (!absolute_redirect || redirect[0] == '/'))
|
| 1103 | return 0;
|
| 1104 |
|
| 1105 | redirect = ovl_get_redirect(dentry, absolute_redirect);
|
| 1106 | if (IS_ERR(redirect))
|
| 1107 | return PTR_ERR(redirect);
|
| 1108 |
|
| 1109 | err = ovl_check_setxattr(ofs, ovl_dentry_upper(dentry),
|
| 1110 | OVL_XATTR_REDIRECT,
|
| 1111 | redirect, strlen(redirect), -EXDEV);
|
| 1112 | if (!err) {
|
| 1113 | spin_lock(&dentry->d_lock);
|
| 1114 | ovl_dentry_set_redirect(dentry, redirect);
|
| 1115 | spin_unlock(&dentry->d_lock);
|
| 1116 | } else {
|
| 1117 | kfree(redirect);
|
| 1118 | pr_warn_ratelimited("failed to set redirect (%i)\n",
|
| 1119 | err);
|
| 1120 |
|
| 1121 | err = -EXDEV;
|
| 1122 | }
|
| 1123 | return err;
|
| 1124 | }
|
| 1125 |
|
| 1126 | struct ovl_renamedata {
|
| 1127 | struct renamedata;
|
| 1128 | struct dentry *opaquedir;
|
| 1129 | bool cleanup_whiteout;
|
| 1130 | bool update_nlink;
|
| 1131 | bool overwrite;
|
| 1132 | };
|
| 1133 |
|
| 1134 | static int ovl_rename_start(struct ovl_renamedata *ovlrd, struct list_head *list)
|
| 1135 | {
|
| 1136 | struct dentry *old = ovlrd->old_dentry;
|
| 1137 | struct dentry *new = ovlrd->new_dentry;
|
| 1138 | bool is_dir = d_is_dir(old);
|
| 1139 | bool new_is_dir = d_is_dir(new);
|
| 1140 | int err;
|
| 1141 |
|
| 1142 | if (ovlrd->flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
|
| 1143 | return -EINVAL;
|
| 1144 |
|
| 1145 | ovlrd->flags &= ~RENAME_NOREPLACE;
|
| 1146 |
|
| 1147 |
|
| 1148 | err = -EXDEV;
|
| 1149 | if (!ovl_can_move(old))
|
| 1150 | return err;
|
| 1151 | if (!ovlrd->overwrite && !ovl_can_move(new))
|
| 1152 | return err;
|
| 1153 |
|
| 1154 | if (ovlrd->overwrite && new_is_dir && !ovl_pure_upper(new)) {
|
| 1155 | err = ovl_check_empty_dir(new, list);
|
| 1156 | if (err)
|
| 1157 | return err;
|
| 1158 | }
|
| 1159 |
|
| 1160 | if (ovlrd->overwrite) {
|
| 1161 | if (ovl_lower_positive(old)) {
|
| 1162 | if (!ovl_dentry_is_whiteout(new)) {
|
| 1163 |
|
| 1164 | ovlrd->flags |= RENAME_WHITEOUT;
|
| 1165 | } else {
|
| 1166 |
|
| 1167 | ovlrd->flags |= RENAME_EXCHANGE;
|
| 1168 | }
|
| 1169 | } else if (is_dir && ovl_dentry_is_whiteout(new)) {
|
| 1170 | ovlrd->flags |= RENAME_EXCHANGE;
|
| 1171 | ovlrd->cleanup_whiteout = true;
|
| 1172 | }
|
| 1173 | }
|
| 1174 |
|
| 1175 | err = ovl_copy_up(old);
|
| 1176 | if (err)
|
| 1177 | return err;
|
| 1178 |
|
| 1179 | err = ovl_copy_up(new->d_parent);
|
| 1180 | if (err)
|
| 1181 | return err;
|
| 1182 |
|
| 1183 | if (!ovlrd->overwrite) {
|
| 1184 | err = ovl_copy_up(new);
|
| 1185 | if (err)
|
| 1186 | return err;
|
| 1187 | } else if (d_inode(new)) {
|
| 1188 | err = ovl_nlink_start(new);
|
| 1189 | if (err)
|
| 1190 | return err;
|
| 1191 |
|
| 1192 | ovlrd->update_nlink = true;
|
| 1193 | }
|
| 1194 |
|
| 1195 | if (!ovlrd->update_nlink) {
|
| 1196 |
|
| 1197 | err = ovl_want_write(old);
|
| 1198 | if (err)
|
| 1199 | return err;
|
| 1200 | }
|
| 1201 |
|
| 1202 | return 0;
|
| 1203 | }
|
| 1204 |
|
| 1205 | static int ovl_rename_upper(struct ovl_renamedata *ovlrd, struct list_head *list)
|
| 1206 | {
|
| 1207 | struct dentry *old = ovlrd->old_dentry;
|
| 1208 | struct dentry *new = ovlrd->new_dentry;
|
| 1209 | struct ovl_fs *ofs = OVL_FS(old->d_sb);
|
| 1210 | struct dentry *old_upperdir = ovl_dentry_upper(old->d_parent);
|
| 1211 | struct dentry *new_upperdir = ovl_dentry_upper(new->d_parent);
|
| 1212 | bool is_dir = d_is_dir(old);
|
| 1213 | bool new_is_dir = d_is_dir(new);
|
| 1214 | bool samedir = old->d_parent == new->d_parent;
|
| 1215 | struct renamedata rd = {};
|
| 1216 | struct dentry *de;
|
| 1217 | struct dentry *whiteout = NULL;
|
| 1218 | bool old_opaque, new_opaque;
|
| 1219 | int err;
|
| 1220 |
|
| 1221 | if (!list_empty(list)) {
|
| 1222 | de = ovl_clear_empty(new, list);
|
| 1223 | if (IS_ERR(de))
|
| 1224 | return PTR_ERR(de);
|
| 1225 | ovlrd->opaquedir = de;
|
| 1226 | }
|
| 1227 |
|
| 1228 | if (!samedir) {
|
| 1229 | |
| 1230 | * When moving a merge dir or non-dir with copy up origin into
|
| 1231 | * a new parent, we are marking the new parent dir "impure".
|
| 1232 | * When ovl_iterate() iterates an "impure" upper dir, it will
|
| 1233 | * lookup the origin inodes of the entries to fill d_ino.
|
| 1234 |
|
| 1235 | if (ovl_type_origin(old)) {
|
| 1236 | err = ovl_set_impure(new->d_parent, new_upperdir);
|
| 1237 | if (err)
|
| 1238 | return err;
|
| 1239 | }
|
| 1240 | if (!ovlrd->overwrite && ovl_type_origin(new)) {
|
| 1241 | err = ovl_set_impure(old->d_parent, old_upperdir);
|
| 1242 | if (err)
|
| 1243 | return err;
|
| 1244 | }
|
| 1245 | }
|
| 1246 |
|
| 1247 | rd.mnt_idmap = ovl_upper_mnt_idmap(ofs);
|
| 1248 | rd.old_parent = old_upperdir;
|
| 1249 | rd.new_parent = new_upperdir;
|
| 1250 | rd.flags = ovlrd->flags;
|
| 1251 |
|
| 1252 | err = start_renaming(&rd, 0,
|
| 1253 | &QSTR_LEN(old->d_name.name, old->d_name.len),
|
| 1254 | &QSTR_LEN(new->d_name.name, new->d_name.len));
|
| 1255 | if (err)
|
| 1256 | return err;
|
| 1257 |
|
| 1258 | err = -ESTALE;
|
| 1259 | if (!ovl_matches_upper(old, rd.old_dentry))
|
| 1260 | goto out_unlock;
|
| 1261 |
|
| 1262 | old_opaque = ovl_dentry_is_opaque(old);
|
| 1263 | new_opaque = ovl_dentry_is_opaque(new);
|
| 1264 |
|
| 1265 | err = -ESTALE;
|
| 1266 | if (d_inode(new) && ovl_dentry_upper(new)) {
|
| 1267 | if (ovlrd->opaquedir) {
|
| 1268 | if (rd.new_dentry != ovlrd->opaquedir)
|
| 1269 | goto out_unlock;
|
| 1270 | } else {
|
| 1271 | if (!ovl_matches_upper(new, rd.new_dentry))
|
| 1272 | goto out_unlock;
|
| 1273 | }
|
| 1274 | } else {
|
| 1275 | if (!d_is_negative(rd.new_dentry)) {
|
| 1276 | if (!new_opaque || !ovl_upper_is_whiteout(ofs, rd.new_dentry))
|
| 1277 | goto out_unlock;
|
| 1278 | } else {
|
| 1279 | if (ovlrd->flags & RENAME_EXCHANGE)
|
| 1280 | goto out_unlock;
|
| 1281 | }
|
| 1282 | }
|
| 1283 |
|
| 1284 | if (rd.old_dentry->d_inode == rd.new_dentry->d_inode)
|
| 1285 | goto out_unlock;
|
| 1286 |
|
| 1287 | err = 0;
|
| 1288 | if (ovl_type_merge_or_lower(old))
|
| 1289 | err = ovl_set_redirect(old, samedir);
|
| 1290 | else if (is_dir && !old_opaque && ovl_type_merge(new->d_parent))
|
| 1291 | err = ovl_set_opaque_xerr(old, rd.old_dentry, -EXDEV);
|
| 1292 | if (err)
|
| 1293 | goto out_unlock;
|
| 1294 |
|
| 1295 | if (!ovlrd->overwrite && ovl_type_merge_or_lower(new))
|
| 1296 | err = ovl_set_redirect(new, samedir);
|
| 1297 | else if (!ovlrd->overwrite && new_is_dir && !new_opaque &&
|
| 1298 | ovl_type_merge(old->d_parent))
|
| 1299 | err = ovl_set_opaque_xerr(new, rd.new_dentry, -EXDEV);
|
| 1300 | if (err)
|
| 1301 | goto out_unlock;
|
| 1302 |
|
| 1303 | err = ovl_do_rename_rd(&rd);
|
| 1304 |
|
| 1305 | if (!err && ovlrd->cleanup_whiteout)
|
| 1306 | whiteout = dget(rd.new_dentry);
|
| 1307 |
|
| 1308 | out_unlock:
|
| 1309 | end_renaming(&rd);
|
| 1310 |
|
| 1311 | if (err)
|
| 1312 | return err;
|
| 1313 |
|
| 1314 | if (whiteout) {
|
| 1315 | ovl_cleanup(ofs, old_upperdir, whiteout);
|
| 1316 | dput(whiteout);
|
| 1317 | }
|
| 1318 |
|
| 1319 | if (ovlrd->overwrite && d_inode(new)) {
|
| 1320 | if (new_is_dir)
|
| 1321 | clear_nlink(d_inode(new));
|
| 1322 | else
|
| 1323 | ovl_drop_nlink(new);
|
| 1324 | }
|
| 1325 |
|
| 1326 | ovl_dir_modified(old->d_parent, ovl_type_origin(old) ||
|
| 1327 | (!ovlrd->overwrite && ovl_type_origin(new)));
|
| 1328 | ovl_dir_modified(new->d_parent, ovl_type_origin(old) ||
|
| 1329 | (d_inode(new) && ovl_type_origin(new)));
|
| 1330 |
|
| 1331 |
|
| 1332 | ovl_copyattr(d_inode(old));
|
| 1333 | if (d_inode(new) && ovl_dentry_upper(new))
|
| 1334 | ovl_copyattr(d_inode(new));
|
| 1335 |
|
| 1336 | return err;
|
| 1337 | }
|
| 1338 |
|
| 1339 | static void ovl_rename_end(struct ovl_renamedata *ovlrd)
|
| 1340 | {
|
| 1341 | if (ovlrd->update_nlink)
|
| 1342 | ovl_nlink_end(ovlrd->new_dentry);
|
| 1343 | else
|
| 1344 | ovl_drop_write(ovlrd->old_dentry);
|
| 1345 | }
|
| 1346 |
|
| 1347 | static int ovl_rename(const struct mnt_idmap *idmap, struct inode *olddir,
|
| 1348 | struct dentry *old, struct inode *newdir,
|
| 1349 | struct dentry *new, unsigned int flags)
|
| 1350 | {
|
| 1351 | struct ovl_renamedata ovlrd = {
|
| 1352 | .old_parent = old->d_parent,
|
| 1353 | .old_dentry = old,
|
| 1354 | .new_parent = new->d_parent,
|
| 1355 | .new_dentry = new,
|
| 1356 | .flags = flags,
|
| 1357 | .overwrite = !(flags & RENAME_EXCHANGE),
|
| 1358 | };
|
| 1359 | LIST_HEAD(list);
|
| 1360 | int err;
|
| 1361 |
|
| 1362 | err = ovl_rename_start(&ovlrd, &list);
|
| 1363 | if (!err) {
|
| 1364 | with_ovl_creds(old->d_sb)
|
| 1365 | err = ovl_rename_upper(&ovlrd, &list);
|
| 1366 | ovl_rename_end(&ovlrd);
|
| 1367 | }
|
| 1368 |
|
| 1369 | dput(ovlrd.opaquedir);
|
| 1370 | ovl_cache_free(&list);
|
| 1371 | return err;
|
| 1372 | }
|
| 1373 |
|
| 1374 | static int ovl_create_tmpfile(struct file *file, struct dentry *dentry,
|
| 1375 | struct inode *inode, umode_t mode)
|
| 1376 | {
|
| 1377 | struct path realparentpath;
|
| 1378 | struct file *realfile;
|
| 1379 | struct ovl_file *of;
|
| 1380 | struct dentry *newdentry;
|
| 1381 |
|
| 1382 | int flags = file->f_flags | OVL_OPEN_FLAGS;
|
| 1383 | int err;
|
| 1384 |
|
| 1385 | scoped_class(override_creds_ovl, original_creds, dentry->d_sb) {
|
| 1386 | scoped_class(ovl_override_creator_creds, cred, original_creds, dentry, inode, mode) {
|
| 1387 | if (IS_ERR(cred))
|
| 1388 | return PTR_ERR(cred);
|
| 1389 |
|
| 1390 | ovl_path_upper(dentry->d_parent, &realparentpath);
|
| 1391 | realfile = backing_tmpfile_open(file, flags, &realparentpath,
|
| 1392 | mode, current_cred());
|
| 1393 | err = PTR_ERR_OR_ZERO(realfile);
|
| 1394 | pr_debug("tmpfile/open(%pd2, 0%o) = %i\n", realparentpath.dentry, mode, err);
|
| 1395 | if (err)
|
| 1396 | return err;
|
| 1397 |
|
| 1398 | of = ovl_file_alloc(realfile);
|
| 1399 | if (!of) {
|
| 1400 | fput(realfile);
|
| 1401 | return -ENOMEM;
|
| 1402 | }
|
| 1403 |
|
| 1404 |
|
| 1405 | newdentry = dget(realfile->f_path.dentry);
|
| 1406 | err = ovl_instantiate(dentry, inode, newdentry, false, file);
|
| 1407 | if (!err) {
|
| 1408 | file->private_data = of;
|
| 1409 | } else {
|
| 1410 | dput(newdentry);
|
| 1411 | ovl_file_free(of);
|
| 1412 | }
|
| 1413 | }
|
| 1414 | }
|
| 1415 | return err;
|
| 1416 | }
|
| 1417 |
|
| 1418 | static int ovl_dummy_open(struct inode *inode, struct file *file)
|
| 1419 | {
|
| 1420 | return 0;
|
| 1421 | }
|
| 1422 |
|
| 1423 | static int ovl_tmpfile(const struct mnt_idmap *idmap, struct inode *dir,
|
| 1424 | struct file *file, umode_t mode)
|
| 1425 | {
|
| 1426 | int err;
|
| 1427 | struct dentry *dentry = file->f_path.dentry;
|
| 1428 | struct inode *inode;
|
| 1429 |
|
| 1430 | if (!OVL_FS(dentry->d_sb)->tmpfile)
|
| 1431 | return -EOPNOTSUPP;
|
| 1432 |
|
| 1433 | err = ovl_copy_up(dentry->d_parent);
|
| 1434 | if (err)
|
| 1435 | return err;
|
| 1436 |
|
| 1437 | err = ovl_want_write(dentry);
|
| 1438 | if (err)
|
| 1439 | return err;
|
| 1440 |
|
| 1441 | err = -ENOMEM;
|
| 1442 | inode = ovl_new_inode(dentry->d_sb, mode, 0);
|
| 1443 | if (!inode)
|
| 1444 | goto drop_write;
|
| 1445 |
|
| 1446 | inode_init_owner(idmap, inode, dir, mode);
|
| 1447 | err = ovl_create_tmpfile(file, dentry, inode, inode->i_mode);
|
| 1448 | if (err)
|
| 1449 | goto put_inode;
|
| 1450 |
|
| 1451 | |
| 1452 | * Check if the preallocated inode was actually used. Having something
|
| 1453 | * else assigned to the dentry shouldn't happen as that would indicate
|
| 1454 | * that the backing tmpfile "leaked" out of overlayfs.
|
| 1455 |
|
| 1456 | err = -EIO;
|
| 1457 | if (WARN_ON(inode != d_inode(dentry)))
|
| 1458 | goto put_realfile;
|
| 1459 |
|
| 1460 |
|
| 1461 | inode = NULL;
|
| 1462 | err = finish_open(file, dentry, ovl_dummy_open);
|
| 1463 | put_realfile:
|
| 1464 |
|
| 1465 | if (!(file->f_mode & FMODE_OPENED))
|
| 1466 | ovl_file_free(file->private_data);
|
| 1467 | put_inode:
|
| 1468 | iput(inode);
|
| 1469 | drop_write:
|
| 1470 | ovl_drop_write(dentry);
|
| 1471 | return err;
|
| 1472 | }
|
| 1473 |
|
| 1474 | const struct inode_operations ovl_dir_inode_operations = {
|
| 1475 | .lookup = ovl_lookup,
|
| 1476 | .mkdir = ovl_mkdir,
|
| 1477 | .symlink = ovl_symlink,
|
| 1478 | .unlink = ovl_unlink,
|
| 1479 | .rmdir = ovl_rmdir,
|
| 1480 | .rename = ovl_rename,
|
| 1481 | .link = ovl_link,
|
| 1482 | .setattr = ovl_setattr,
|
| 1483 | .create = ovl_create,
|
| 1484 | .mknod = ovl_mknod,
|
| 1485 | .permission = ovl_permission,
|
| 1486 | .getattr = ovl_getattr,
|
| 1487 | .listxattr = ovl_listxattr,
|
| 1488 | .get_inode_acl = ovl_get_inode_acl,
|
| 1489 | .get_acl = ovl_get_acl,
|
| 1490 | .set_acl = ovl_set_acl,
|
| 1491 | .update_time = ovl_update_time,
|
| 1492 | .fileattr_get = ovl_fileattr_get,
|
| 1493 | .fileattr_set = ovl_fileattr_set,
|
| 1494 | .tmpfile = ovl_tmpfile,
|
| 1495 | };
|