1 // SPDX-License-Identifier: GPL-2.0-only
4 * Copyright (C) 2011 Novell Inc.
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 "overlayfs.h"
19 static unsigned short ovl_redirect_max = 256;
20 module_param_named(redirect_max, ovl_redirect_max, ushort, 0644);
21 MODULE_PARM_DESC(redirect_max,
22 "Maximum length of absolute redirect xattr value");
24 static int ovl_set_redirect(struct dentry *dentry, bool samedir);
26 int ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
31 if (d_is_dir(wdentry))
32 err = ovl_do_rmdir(wdir, wdentry);
34 err = ovl_do_unlink(wdir, wdentry);
38 pr_err("cleanup of '%pd2' failed (%i)\n",
45 struct dentry *ovl_lookup_temp(struct dentry *workdir)
49 static atomic_t temp_id = ATOMIC_INIT(0);
51 /* counter is allowed to wrap, since temp dentries are ephemeral */
52 snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id));
54 temp = lookup_one_len(name, workdir, strlen(name));
55 if (!IS_ERR(temp) && temp->d_inode) {
56 pr_err("workdir/%s already exists\n", name);
64 /* caller holds i_mutex on workdir */
65 static struct dentry *ovl_whiteout(struct ovl_fs *ofs)
68 struct dentry *whiteout;
69 struct dentry *workdir = ofs->workdir;
70 struct inode *wdir = workdir->d_inode;
73 whiteout = ovl_lookup_temp(workdir);
77 err = ovl_do_whiteout(wdir, whiteout);
80 whiteout = ERR_PTR(err);
83 ofs->whiteout = whiteout;
86 if (ofs->share_whiteout) {
87 whiteout = ovl_lookup_temp(workdir);
91 err = ovl_do_link(ofs->whiteout, wdir, whiteout);
96 pr_warn("Failed to link whiteout - disabling whiteout inode sharing(nlink=%u, err=%i)\n",
97 ofs->whiteout->d_inode->i_nlink, err);
98 ofs->share_whiteout = false;
102 whiteout = ofs->whiteout;
103 ofs->whiteout = NULL;
108 /* Caller must hold i_mutex on both workdir and dir */
109 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
110 struct dentry *dentry)
112 struct inode *wdir = ofs->workdir->d_inode;
113 struct dentry *whiteout;
117 whiteout = ovl_whiteout(ofs);
118 err = PTR_ERR(whiteout);
119 if (IS_ERR(whiteout))
122 if (d_is_dir(dentry))
123 flags = RENAME_EXCHANGE;
125 err = ovl_do_rename(wdir, whiteout, dir, dentry, flags);
129 ovl_cleanup(wdir, dentry);
136 ovl_cleanup(wdir, whiteout);
140 int ovl_mkdir_real(struct inode *dir, struct dentry **newdentry, umode_t mode)
143 struct dentry *d, *dentry = *newdentry;
145 err = ovl_do_mkdir(dir, dentry, mode);
149 if (likely(!d_unhashed(dentry)))
153 * vfs_mkdir() may succeed and leave the dentry passed
154 * to it unhashed and negative. If that happens, try to
155 * lookup a new hashed and positive dentry.
157 d = lookup_one_len(dentry->d_name.name, dentry->d_parent,
160 pr_warn("failed lookup after mkdir (%pd2, err=%i).\n",
170 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
171 struct ovl_cattr *attr)
175 if (IS_ERR(newdentry))
179 if (newdentry->d_inode)
182 if (attr->hardlink) {
183 err = ovl_do_link(attr->hardlink, dir, newdentry);
185 switch (attr->mode & S_IFMT) {
187 err = ovl_do_create(dir, newdentry, attr->mode);
191 /* mkdir is special... */
192 err = ovl_mkdir_real(dir, &newdentry, attr->mode);
199 err = ovl_do_mknod(dir, newdentry, attr->mode,
204 err = ovl_do_symlink(dir, newdentry, attr->link);
211 if (!err && WARN_ON(!newdentry->d_inode)) {
213 * Not quite sure if non-instantiated dentry is legal or not.
214 * VFS doesn't seem to care so check and warn here.
226 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr)
228 return ovl_create_real(d_inode(workdir), ovl_lookup_temp(workdir),
232 static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper,
235 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
238 err = ovl_check_setxattr(ofs, upper, OVL_XATTR_OPAQUE, "y", 1, xerr);
240 ovl_dentry_set_opaque(dentry);
245 static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
248 * Fail with -EIO when trying to create opaque dir and upper doesn't
249 * support xattrs. ovl_rename() calls ovl_set_opaque_xerr(-EXDEV) to
250 * return a specific error for noxattr case.
252 return ovl_set_opaque_xerr(dentry, upperdentry, -EIO);
256 * Common operations required to be done after creation of file on upper.
257 * If @hardlink is false, then @inode is a pre-allocated inode, we may or
258 * may not use to instantiate the new dentry.
260 static int ovl_instantiate(struct dentry *dentry, struct inode *inode,
261 struct dentry *newdentry, bool hardlink)
263 struct ovl_inode_params oip = {
264 .upperdentry = newdentry,
268 ovl_dir_modified(dentry->d_parent, false);
269 ovl_dentry_set_upper_alias(dentry);
270 ovl_dentry_init_reval(dentry, newdentry);
274 * ovl_obtain_alias() can be called after ovl_create_real()
275 * and before we get here, so we may get an inode from cache
276 * with the same real upperdentry that is not the inode we
277 * pre-allocated. In this case we will use the cached inode
278 * to instantiate the new dentry.
280 * XXX: if we ever use ovl_obtain_alias() to decode directory
281 * file handles, need to use ovl_get_inode_locked() and
282 * d_instantiate_new() here to prevent from creating two
283 * hashed directory inode aliases.
285 inode = ovl_get_inode(dentry->d_sb, &oip);
287 return PTR_ERR(inode);
288 if (inode == oip.newinode)
289 ovl_set_flag(OVL_UPPERDATA, inode);
291 WARN_ON(ovl_inode_real(inode) != d_inode(newdentry));
296 d_instantiate(dentry, inode);
297 if (inode != oip.newinode) {
298 pr_warn_ratelimited("newly created inode found in cache (%pd2)\n",
302 /* Force lookup of new upper hardlink to find its lower */
309 static bool ovl_type_merge(struct dentry *dentry)
311 return OVL_TYPE_MERGE(ovl_path_type(dentry));
314 static bool ovl_type_origin(struct dentry *dentry)
316 return OVL_TYPE_ORIGIN(ovl_path_type(dentry));
319 static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
320 struct ovl_cattr *attr)
322 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
323 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
324 struct inode *udir = upperdir->d_inode;
325 struct dentry *newdentry;
328 if (!attr->hardlink && !IS_POSIXACL(udir))
329 attr->mode &= ~current_umask();
331 inode_lock_nested(udir, I_MUTEX_PARENT);
332 newdentry = ovl_create_real(udir,
333 lookup_one_len(dentry->d_name.name,
337 err = PTR_ERR(newdentry);
338 if (IS_ERR(newdentry))
341 if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry) &&
342 !ovl_allow_offline_changes(ofs)) {
343 /* Setting opaque here is just an optimization, allow to fail */
344 ovl_set_opaque(dentry, newdentry);
347 err = ovl_instantiate(dentry, inode, newdentry, !!attr->hardlink);
355 ovl_cleanup(udir, newdentry);
360 static struct dentry *ovl_clear_empty(struct dentry *dentry,
361 struct list_head *list)
363 struct dentry *workdir = ovl_workdir(dentry);
364 struct inode *wdir = workdir->d_inode;
365 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
366 struct inode *udir = upperdir->d_inode;
367 struct path upperpath;
368 struct dentry *upper;
369 struct dentry *opaquedir;
373 if (WARN_ON(!workdir))
374 return ERR_PTR(-EROFS);
376 err = ovl_lock_rename_workdir(workdir, upperdir);
380 ovl_path_upper(dentry, &upperpath);
381 err = vfs_getattr(&upperpath, &stat,
382 STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
387 if (!S_ISDIR(stat.mode))
389 upper = upperpath.dentry;
390 if (upper->d_parent->d_inode != udir)
393 opaquedir = ovl_create_temp(workdir, OVL_CATTR(stat.mode));
394 err = PTR_ERR(opaquedir);
395 if (IS_ERR(opaquedir))
398 err = ovl_copy_xattr(dentry->d_sb, upper, opaquedir);
402 err = ovl_set_opaque(dentry, opaquedir);
406 inode_lock(opaquedir->d_inode);
407 err = ovl_set_attr(opaquedir, &stat);
408 inode_unlock(opaquedir->d_inode);
412 err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE);
416 ovl_cleanup_whiteouts(upper, list);
417 ovl_cleanup(wdir, upper);
418 unlock_rename(workdir, upperdir);
420 /* dentry's upper doesn't match now, get rid of it */
426 ovl_cleanup(wdir, opaquedir);
429 unlock_rename(workdir, upperdir);
434 static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name,
435 const struct posix_acl *acl)
441 if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl)
444 size = posix_acl_xattr_size(acl->a_count);
445 buffer = kmalloc(size, GFP_KERNEL);
449 err = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
453 err = vfs_setxattr(&init_user_ns, upperdentry, name, buffer, size, XATTR_CREATE);
459 static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
460 struct ovl_cattr *cattr)
462 struct dentry *workdir = ovl_workdir(dentry);
463 struct inode *wdir = workdir->d_inode;
464 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
465 struct inode *udir = upperdir->d_inode;
466 struct dentry *upper;
467 struct dentry *newdentry;
469 struct posix_acl *acl, *default_acl;
470 bool hardlink = !!cattr->hardlink;
472 if (WARN_ON(!workdir))
476 err = posix_acl_create(dentry->d_parent->d_inode,
477 &cattr->mode, &default_acl, &acl);
482 err = ovl_lock_rename_workdir(workdir, upperdir);
486 upper = lookup_one_len(dentry->d_name.name, upperdir,
488 err = PTR_ERR(upper);
493 if (d_is_negative(upper) || !IS_WHITEOUT(d_inode(upper)))
496 newdentry = ovl_create_temp(workdir, cattr);
497 err = PTR_ERR(newdentry);
498 if (IS_ERR(newdentry))
502 * mode could have been mutilated due to umask (e.g. sgid directory)
505 !S_ISLNK(cattr->mode) &&
506 newdentry->d_inode->i_mode != cattr->mode) {
507 struct iattr attr = {
508 .ia_valid = ATTR_MODE,
509 .ia_mode = cattr->mode,
511 inode_lock(newdentry->d_inode);
512 err = notify_change(&init_user_ns, newdentry, &attr, NULL);
513 inode_unlock(newdentry->d_inode);
518 err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS,
523 err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT,
529 if (!hardlink && S_ISDIR(cattr->mode)) {
530 err = ovl_set_opaque(dentry, newdentry);
534 err = ovl_do_rename(wdir, newdentry, udir, upper,
539 ovl_cleanup(wdir, upper);
541 err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
545 err = ovl_instantiate(dentry, inode, newdentry, hardlink);
547 ovl_cleanup(udir, newdentry);
553 unlock_rename(workdir, upperdir);
556 posix_acl_release(acl);
557 posix_acl_release(default_acl);
562 ovl_cleanup(wdir, newdentry);
567 static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
568 struct ovl_cattr *attr, bool origin)
571 const struct cred *old_cred;
572 struct cred *override_cred;
573 struct dentry *parent = dentry->d_parent;
575 err = ovl_copy_up(parent);
579 old_cred = ovl_override_creds(dentry->d_sb);
582 * When linking a file with copy up origin into a new parent, mark the
583 * new parent dir "impure".
586 err = ovl_set_impure(parent, ovl_dentry_upper(parent));
588 goto out_revert_creds;
591 if (!attr->hardlink) {
593 override_cred = prepare_creds();
595 goto out_revert_creds;
597 * In the creation cases(create, mkdir, mknod, symlink),
598 * ovl should transfer current's fs{u,g}id to underlying
599 * fs. Because underlying fs want to initialize its new
600 * inode owner using current's fs{u,g}id. And in this
601 * case, the @inode is a new inode that is initialized
602 * in inode_init_owner() to current's fs{u,g}id. So use
603 * the inode's i_{u,g}id to override the cred's fs{u,g}id.
605 * But in the other hardlink case, ovl_link() does not
606 * create a new inode, so just use the ovl mounter's
609 override_cred->fsuid = inode->i_uid;
610 override_cred->fsgid = inode->i_gid;
611 err = security_dentry_create_files_as(dentry,
612 attr->mode, &dentry->d_name, old_cred,
615 put_cred(override_cred);
616 goto out_revert_creds;
618 put_cred(override_creds(override_cred));
619 put_cred(override_cred);
622 if (!ovl_dentry_is_whiteout(dentry))
623 err = ovl_create_upper(dentry, inode, attr);
625 err = ovl_create_over_whiteout(dentry, inode, attr);
628 revert_creds(old_cred);
632 static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
637 struct ovl_cattr attr = {
642 err = ovl_want_write(dentry);
646 /* Preallocate inode to be used by ovl_get_inode() */
648 inode = ovl_new_inode(dentry->d_sb, mode, rdev);
652 spin_lock(&inode->i_lock);
653 inode->i_state |= I_CREATING;
654 spin_unlock(&inode->i_lock);
656 inode_init_owner(&init_user_ns, inode, dentry->d_parent->d_inode, mode);
657 attr.mode = inode->i_mode;
659 err = ovl_create_or_link(dentry, inode, &attr, false);
660 /* Did we end up using the preallocated inode? */
661 if (inode != d_inode(dentry))
665 ovl_drop_write(dentry);
670 static int ovl_create(struct user_namespace *mnt_userns, struct inode *dir,
671 struct dentry *dentry, umode_t mode, bool excl)
673 return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
676 static int ovl_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
677 struct dentry *dentry, umode_t mode)
679 return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
682 static int ovl_mknod(struct user_namespace *mnt_userns, struct inode *dir,
683 struct dentry *dentry, umode_t mode, dev_t rdev)
685 /* Don't allow creation of "whiteout" on overlay */
686 if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
689 return ovl_create_object(dentry, mode, rdev, NULL);
692 static int ovl_symlink(struct user_namespace *mnt_userns, struct inode *dir,
693 struct dentry *dentry, const char *link)
695 return ovl_create_object(dentry, S_IFLNK, 0, link);
698 static int ovl_set_link_redirect(struct dentry *dentry)
700 const struct cred *old_cred;
703 old_cred = ovl_override_creds(dentry->d_sb);
704 err = ovl_set_redirect(dentry, false);
705 revert_creds(old_cred);
710 static int ovl_link(struct dentry *old, struct inode *newdir,
716 err = ovl_want_write(old);
720 err = ovl_copy_up(old);
724 err = ovl_copy_up(new->d_parent);
728 if (ovl_is_metacopy_dentry(old)) {
729 err = ovl_set_link_redirect(old);
734 err = ovl_nlink_start(old);
738 inode = d_inode(old);
741 err = ovl_create_or_link(new, inode,
742 &(struct ovl_cattr) {.hardlink = ovl_dentry_upper(old)},
743 ovl_type_origin(old));
754 static bool ovl_matches_upper(struct dentry *dentry, struct dentry *upper)
756 return d_inode(ovl_dentry_upper(dentry)) == d_inode(upper);
759 static int ovl_remove_and_whiteout(struct dentry *dentry,
760 struct list_head *list)
762 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
763 struct dentry *workdir = ovl_workdir(dentry);
764 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
765 struct dentry *upper;
766 struct dentry *opaquedir = NULL;
769 if (WARN_ON(!workdir))
772 if (!list_empty(list)) {
773 opaquedir = ovl_clear_empty(dentry, list);
774 err = PTR_ERR(opaquedir);
775 if (IS_ERR(opaquedir))
779 err = ovl_lock_rename_workdir(workdir, upperdir);
783 upper = lookup_one_len(dentry->d_name.name, upperdir,
785 err = PTR_ERR(upper);
790 if ((opaquedir && upper != opaquedir) ||
791 (!opaquedir && ovl_dentry_upper(dentry) &&
792 !ovl_matches_upper(dentry, upper))) {
796 err = ovl_cleanup_and_whiteout(ofs, d_inode(upperdir), upper);
800 ovl_dir_modified(dentry->d_parent, true);
806 unlock_rename(workdir, upperdir);
813 static int ovl_remove_upper(struct dentry *dentry, bool is_dir,
814 struct list_head *list)
816 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
817 struct inode *dir = upperdir->d_inode;
818 struct dentry *upper;
819 struct dentry *opaquedir = NULL;
822 if (!list_empty(list)) {
823 opaquedir = ovl_clear_empty(dentry, list);
824 err = PTR_ERR(opaquedir);
825 if (IS_ERR(opaquedir))
829 inode_lock_nested(dir, I_MUTEX_PARENT);
830 upper = lookup_one_len(dentry->d_name.name, upperdir,
832 err = PTR_ERR(upper);
837 if ((opaquedir && upper != opaquedir) ||
838 (!opaquedir && !ovl_matches_upper(dentry, upper)))
842 err = vfs_rmdir(&init_user_ns, dir, upper);
844 err = vfs_unlink(&init_user_ns, dir, upper, NULL);
845 ovl_dir_modified(dentry->d_parent, ovl_type_origin(dentry));
848 * Keeping this dentry hashed would mean having to release
849 * upperpath/lowerpath, which could only be done if we are the
850 * sole user of this dentry. Too tricky... Just unhash for
864 static bool ovl_pure_upper(struct dentry *dentry)
866 return !ovl_dentry_lower(dentry) &&
867 !ovl_test_flag(OVL_WHITEOUTS, d_inode(dentry));
870 static void ovl_drop_nlink(struct dentry *dentry)
872 struct inode *inode = d_inode(dentry);
873 struct dentry *alias;
875 /* Try to find another, hashed alias */
876 spin_lock(&inode->i_lock);
877 hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
878 if (alias != dentry && !d_unhashed(alias))
881 spin_unlock(&inode->i_lock);
884 * Changes to underlying layers may cause i_nlink to lose sync with
885 * reality. In this case prevent the link count from going to zero
888 if (inode->i_nlink > !!alias)
892 static int ovl_do_remove(struct dentry *dentry, bool is_dir)
895 const struct cred *old_cred;
896 bool lower_positive = ovl_lower_positive(dentry);
899 /* No need to clean pure upper removed by vfs_rmdir() */
900 if (is_dir && (lower_positive || !ovl_pure_upper(dentry))) {
901 err = ovl_check_empty_dir(dentry, &list);
906 err = ovl_want_write(dentry);
910 err = ovl_copy_up(dentry->d_parent);
914 err = ovl_nlink_start(dentry);
918 old_cred = ovl_override_creds(dentry->d_sb);
920 err = ovl_remove_upper(dentry, is_dir, &list);
922 err = ovl_remove_and_whiteout(dentry, &list);
923 revert_creds(old_cred);
926 clear_nlink(dentry->d_inode);
928 ovl_drop_nlink(dentry);
930 ovl_nlink_end(dentry);
935 * Note: we fail to update ctime if there was no copy-up, only a
938 if (ovl_dentry_upper(dentry))
939 ovl_copyattr(d_inode(dentry));
942 ovl_drop_write(dentry);
944 ovl_cache_free(&list);
948 static int ovl_unlink(struct inode *dir, struct dentry *dentry)
950 return ovl_do_remove(dentry, false);
953 static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
955 return ovl_do_remove(dentry, true);
958 static bool ovl_type_merge_or_lower(struct dentry *dentry)
960 enum ovl_path_type type = ovl_path_type(dentry);
962 return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type);
965 static bool ovl_can_move(struct dentry *dentry)
967 return ovl_redirect_dir(dentry->d_sb) ||
968 !d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry);
971 static char *ovl_get_redirect(struct dentry *dentry, bool abs_redirect)
974 struct dentry *d, *tmp;
975 int buflen = ovl_redirect_max + 1;
978 ret = kstrndup(dentry->d_name.name, dentry->d_name.len,
983 buf = ret = kmalloc(buflen, GFP_KERNEL);
989 for (d = dget(dentry); !IS_ROOT(d);) {
993 spin_lock(&d->d_lock);
994 name = ovl_dentry_get_redirect(d);
996 thislen = strlen(name);
998 name = d->d_name.name;
999 thislen = d->d_name.len;
1002 /* If path is too long, fall back to userspace move */
1003 if (thislen + (name[0] != '/') > buflen) {
1004 ret = ERR_PTR(-EXDEV);
1005 spin_unlock(&d->d_lock);
1010 memcpy(&buf[buflen], name, thislen);
1011 spin_unlock(&d->d_lock);
1012 tmp = dget_parent(d);
1017 /* Absolute redirect: finished */
1018 if (buf[buflen] == '/')
1023 ret = kstrdup(&buf[buflen], GFP_KERNEL);
1028 return ret ? ret : ERR_PTR(-ENOMEM);
1031 static bool ovl_need_absolute_redirect(struct dentry *dentry, bool samedir)
1033 struct dentry *lowerdentry;
1038 if (d_is_dir(dentry))
1042 * For non-dir hardlinked files, we need absolute redirects
1043 * in general as two upper hardlinks could be in different
1044 * dirs. We could put a relative redirect now and convert
1045 * it to absolute redirect later. But when nlink > 1 and
1046 * indexing is on, that means relative redirect needs to be
1047 * converted to absolute during copy up of another lower
1048 * hardllink as well.
1050 * So without optimizing too much, just check if lower is
1051 * a hard link or not. If lower is hard link, put absolute
1054 lowerdentry = ovl_dentry_lower(dentry);
1055 return (d_inode(lowerdentry)->i_nlink > 1);
1058 static int ovl_set_redirect(struct dentry *dentry, bool samedir)
1061 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
1062 const char *redirect = ovl_dentry_get_redirect(dentry);
1063 bool absolute_redirect = ovl_need_absolute_redirect(dentry, samedir);
1065 if (redirect && (!absolute_redirect || redirect[0] == '/'))
1068 redirect = ovl_get_redirect(dentry, absolute_redirect);
1069 if (IS_ERR(redirect))
1070 return PTR_ERR(redirect);
1072 err = ovl_check_setxattr(ofs, ovl_dentry_upper(dentry),
1074 redirect, strlen(redirect), -EXDEV);
1076 spin_lock(&dentry->d_lock);
1077 ovl_dentry_set_redirect(dentry, redirect);
1078 spin_unlock(&dentry->d_lock);
1081 pr_warn_ratelimited("failed to set redirect (%i)\n",
1083 /* Fall back to userspace copy-up */
1089 static int ovl_rename(struct user_namespace *mnt_userns, struct inode *olddir,
1090 struct dentry *old, struct inode *newdir,
1091 struct dentry *new, unsigned int flags)
1094 struct dentry *old_upperdir;
1095 struct dentry *new_upperdir;
1096 struct dentry *olddentry;
1097 struct dentry *newdentry;
1098 struct dentry *trap;
1101 bool cleanup_whiteout = false;
1102 bool update_nlink = false;
1103 bool overwrite = !(flags & RENAME_EXCHANGE);
1104 bool is_dir = d_is_dir(old);
1105 bool new_is_dir = d_is_dir(new);
1106 bool samedir = olddir == newdir;
1107 struct dentry *opaquedir = NULL;
1108 const struct cred *old_cred = NULL;
1112 if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
1115 flags &= ~RENAME_NOREPLACE;
1117 /* Don't copy up directory trees */
1119 if (!ovl_can_move(old))
1121 if (!overwrite && !ovl_can_move(new))
1124 if (overwrite && new_is_dir && !ovl_pure_upper(new)) {
1125 err = ovl_check_empty_dir(new, &list);
1131 if (ovl_lower_positive(old)) {
1132 if (!ovl_dentry_is_whiteout(new)) {
1133 /* Whiteout source */
1134 flags |= RENAME_WHITEOUT;
1136 /* Switch whiteouts */
1137 flags |= RENAME_EXCHANGE;
1139 } else if (is_dir && ovl_dentry_is_whiteout(new)) {
1140 flags |= RENAME_EXCHANGE;
1141 cleanup_whiteout = true;
1145 err = ovl_want_write(old);
1149 err = ovl_copy_up(old);
1151 goto out_drop_write;
1153 err = ovl_copy_up(new->d_parent);
1155 goto out_drop_write;
1157 err = ovl_copy_up(new);
1159 goto out_drop_write;
1160 } else if (d_inode(new)) {
1161 err = ovl_nlink_start(new);
1163 goto out_drop_write;
1165 update_nlink = true;
1168 old_cred = ovl_override_creds(old->d_sb);
1170 if (!list_empty(&list)) {
1171 opaquedir = ovl_clear_empty(new, &list);
1172 err = PTR_ERR(opaquedir);
1173 if (IS_ERR(opaquedir)) {
1175 goto out_revert_creds;
1179 old_upperdir = ovl_dentry_upper(old->d_parent);
1180 new_upperdir = ovl_dentry_upper(new->d_parent);
1184 * When moving a merge dir or non-dir with copy up origin into
1185 * a new parent, we are marking the new parent dir "impure".
1186 * When ovl_iterate() iterates an "impure" upper dir, it will
1187 * lookup the origin inodes of the entries to fill d_ino.
1189 if (ovl_type_origin(old)) {
1190 err = ovl_set_impure(new->d_parent, new_upperdir);
1192 goto out_revert_creds;
1194 if (!overwrite && ovl_type_origin(new)) {
1195 err = ovl_set_impure(old->d_parent, old_upperdir);
1197 goto out_revert_creds;
1201 trap = lock_rename(new_upperdir, old_upperdir);
1203 olddentry = lookup_one_len(old->d_name.name, old_upperdir,
1205 err = PTR_ERR(olddentry);
1206 if (IS_ERR(olddentry))
1210 if (!ovl_matches_upper(old, olddentry))
1213 newdentry = lookup_one_len(new->d_name.name, new_upperdir,
1215 err = PTR_ERR(newdentry);
1216 if (IS_ERR(newdentry))
1219 old_opaque = ovl_dentry_is_opaque(old);
1220 new_opaque = ovl_dentry_is_opaque(new);
1223 if (d_inode(new) && ovl_dentry_upper(new)) {
1225 if (newdentry != opaquedir)
1228 if (!ovl_matches_upper(new, newdentry))
1232 if (!d_is_negative(newdentry)) {
1233 if (!new_opaque || !ovl_is_whiteout(newdentry))
1236 if (flags & RENAME_EXCHANGE)
1241 if (olddentry == trap)
1243 if (newdentry == trap)
1246 if (olddentry->d_inode == newdentry->d_inode)
1250 if (ovl_type_merge_or_lower(old))
1251 err = ovl_set_redirect(old, samedir);
1252 else if (is_dir && !old_opaque && ovl_type_merge(new->d_parent))
1253 err = ovl_set_opaque_xerr(old, olddentry, -EXDEV);
1257 if (!overwrite && ovl_type_merge_or_lower(new))
1258 err = ovl_set_redirect(new, samedir);
1259 else if (!overwrite && new_is_dir && !new_opaque &&
1260 ovl_type_merge(old->d_parent))
1261 err = ovl_set_opaque_xerr(new, newdentry, -EXDEV);
1265 err = ovl_do_rename(old_upperdir->d_inode, olddentry,
1266 new_upperdir->d_inode, newdentry, flags);
1270 if (cleanup_whiteout)
1271 ovl_cleanup(old_upperdir->d_inode, newdentry);
1273 if (overwrite && d_inode(new)) {
1275 clear_nlink(d_inode(new));
1277 ovl_drop_nlink(new);
1280 ovl_dir_modified(old->d_parent, ovl_type_origin(old) ||
1281 (!overwrite && ovl_type_origin(new)));
1282 ovl_dir_modified(new->d_parent, ovl_type_origin(old) ||
1283 (d_inode(new) && ovl_type_origin(new)));
1286 ovl_copyattr(d_inode(old));
1287 if (d_inode(new) && ovl_dentry_upper(new))
1288 ovl_copyattr(d_inode(new));
1295 unlock_rename(new_upperdir, old_upperdir);
1297 revert_creds(old_cred);
1301 ovl_drop_write(old);
1304 ovl_cache_free(&list);
1308 const struct inode_operations ovl_dir_inode_operations = {
1309 .lookup = ovl_lookup,
1311 .symlink = ovl_symlink,
1312 .unlink = ovl_unlink,
1314 .rename = ovl_rename,
1316 .setattr = ovl_setattr,
1317 .create = ovl_create,
1319 .permission = ovl_permission,
1320 .getattr = ovl_getattr,
1321 .listxattr = ovl_listxattr,
1322 .get_acl = ovl_get_acl,
1323 .update_time = ovl_update_time,
1324 .fileattr_get = ovl_fileattr_get,
1325 .fileattr_set = ovl_fileattr_set,