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2023-12-06 08f87f769b595151be1afeff53e144f543faa614 
 kernel/fs/overlayfs/util.c
....@@ -1,10 +1,7 @@
1
+// SPDX-License-Identifier: GPL-2.0-only
12 /*
23  * Copyright (C) 2011 Novell Inc.
34  * Copyright (C) 2016 Red Hat, Inc.
4
- *
5
- * This program is free software; you can redistribute it and/or modify it
6
- * under the terms of the GNU General Public License version 2 as published by
7
- * the Free Software Foundation.
85  */
96 
107 #include <linux/fs.h>
....@@ -21,13 +18,13 @@
2118 int ovl_want_write(struct dentry *dentry)
2219 {
2320 	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
24
-	return mnt_want_write(ofs->upper_mnt);
21
+	return mnt_want_write(ovl_upper_mnt(ofs));
2522 }
2623 
2724 void ovl_drop_write(struct dentry *dentry)
2825 {
2926 	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
30
-	mnt_drop_write(ofs->upper_mnt);
27
+	mnt_drop_write(ovl_upper_mnt(ofs));
3128 }
3229 
3330 struct dentry *ovl_workdir(struct dentry *dentry)
....@@ -45,28 +42,10 @@
4542 	return override_creds(ofs->creator_cred);
4643 }
4744 
48
-void ovl_revert_creds(const struct cred *old_cred)
45
+void ovl_revert_creds(struct super_block *sb, const struct cred *old_cred)
4946 {
5047 	if (old_cred)
5148 		revert_creds(old_cred);
52
-}
53
-
54
-ssize_t ovl_vfs_getxattr(struct dentry *dentry, const char *name, void *buf,
55
-			 size_t size)
56
-{
57
-	return __vfs_getxattr(dentry, d_inode(dentry), name, buf, size);
58
-}
59
-
60
-struct super_block *ovl_same_sb(struct super_block *sb)
61
-{
62
-	struct ovl_fs *ofs = sb->s_fs_info;
63
-
64
-	if (!ofs->numlowerfs)
65
-		return ofs->upper_mnt->mnt_sb;
66
-	else if (ofs->numlowerfs == 1 && !ofs->upper_mnt)
67
-		return ofs->lower_fs[0].sb;
68
-	else
69
-		return NULL;
7049 }
7150 
7251 /*
....@@ -79,8 +58,7 @@
7958  */
8059 int ovl_can_decode_fh(struct super_block *sb)
8160 {
82
-	if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry ||
83
-	    uuid_is_null(&sb->s_uuid))
61
+	if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry)
8462 		return 0;
8563 
8664 	return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN;
....@@ -123,8 +101,24 @@
123101 bool ovl_dentry_remote(struct dentry *dentry)
124102 {
125103 	return dentry->d_flags &
126
-		(DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
127
-		 DCACHE_OP_REAL);
104
+		(DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE);
105
+}
106
+
107
+void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry,
108
+			     unsigned int mask)
109
+{
110
+	struct ovl_entry *oe = OVL_E(dentry);
111
+	unsigned int i, flags = 0;
112
+
113
+	if (upperdentry)
114
+		flags |= upperdentry->d_flags;
115
+	for (i = 0; i < oe->numlower; i++)
116
+		flags |= oe->lowerstack[i].dentry->d_flags;
117
+
118
+	spin_lock(&dentry->d_lock);
119
+	dentry->d_flags &= ~mask;
120
+	dentry->d_flags |= flags & mask;
121
+	spin_unlock(&dentry->d_lock);
128122 }
129123 
130124 bool ovl_dentry_weird(struct dentry *dentry)
....@@ -164,7 +158,7 @@
164158 {
165159 	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
166160 
167
-	path->mnt = ofs->upper_mnt;
161
+	path->mnt = ovl_upper_mnt(ofs);
168162 	path->dentry = ovl_dentry_upper(dentry);
169163 }
170164 
....@@ -216,7 +210,7 @@
216210 	return oe->numlower ? oe->lowerstack[0].dentry : NULL;
217211 }
218212 
219
-struct ovl_layer *ovl_layer_lower(struct dentry *dentry)
213
+const struct ovl_layer *ovl_layer_lower(struct dentry *dentry)
220214 {
221215 	struct ovl_entry *oe = dentry->d_fsdata;
222216 
....@@ -416,24 +410,6 @@
416410 	oi->redirect = redirect;
417411 }
418412 
419
-void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
420
-		    struct dentry *lowerdentry, struct dentry *lowerdata)
421
-{
422
-	struct inode *realinode = d_inode(upperdentry ?: lowerdentry);
423
-
424
-	if (upperdentry)
425
-		OVL_I(inode)->__upperdentry = upperdentry;
426
-	if (lowerdentry)
427
-		OVL_I(inode)->lower = igrab(d_inode(lowerdentry));
428
-	if (lowerdata)
429
-		OVL_I(inode)->lowerdata = igrab(d_inode(lowerdata));
430
-
431
-	ovl_copyattr(realinode, inode);
432
-	ovl_copyflags(realinode, inode);
433
-	if (!inode->i_ino)
434
-		inode->i_ino = realinode->i_ino;
435
-}
436
-
437413 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry)
438414 {
439415 	struct inode *upperinode = d_inode(upperdentry);
....@@ -446,25 +422,25 @@
446422 	smp_wmb();
447423 	OVL_I(inode)->__upperdentry = upperdentry;
448424 	if (inode_unhashed(inode)) {
449
-		if (!inode->i_ino)
450
-			inode->i_ino = upperinode->i_ino;
451425 		inode->i_private = upperinode;
452426 		__insert_inode_hash(inode, (unsigned long) upperinode);
453427 	}
454428 }
455429 
456
-static void ovl_dentry_version_inc(struct dentry *dentry, bool impurity)
430
+static void ovl_dir_version_inc(struct dentry *dentry, bool impurity)
457431 {
458432 	struct inode *inode = d_inode(dentry);
459433 
460434 	WARN_ON(!inode_is_locked(inode));
435
+	WARN_ON(!d_is_dir(dentry));
461436 	/*
462
-	 * Version is used by readdir code to keep cache consistent.  For merge
463
-	 * dirs all changes need to be noted.  For non-merge dirs, cache only
464
-	 * contains impure (ones which have been copied up and have origins)
465
-	 * entries, so only need to note changes to impure entries.
437
+	 * Version is used by readdir code to keep cache consistent.
438
+	 * For merge dirs (or dirs with origin) all changes need to be noted.
439
+	 * For non-merge dirs, cache contains only impure entries (i.e. ones
440
+	 * which have been copied up and have origins), so only need to note
441
+	 * changes to impure entries.
466442 	 */
467
-	if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity)
443
+	if (!ovl_dir_is_real(dentry) || impurity)
468444 		OVL_I(inode)->version++;
469445 }
470446 
....@@ -473,7 +449,7 @@
473449 	/* Copy mtime/ctime */
474450 	ovl_copyattr(d_inode(ovl_dentry_upper(dentry)), d_inode(dentry));
475451 
476
-	ovl_dentry_version_inc(dentry, impurity);
452
+	ovl_dir_version_inc(dentry, impurity);
477453 }
478454 
479455 u64 ovl_dentry_version_get(struct dentry *dentry)
....@@ -493,7 +469,32 @@
493469 
494470 struct file *ovl_path_open(struct path *path, int flags)
495471 {
496
-	return dentry_open(path, flags | O_NOATIME, current_cred());
472
+	struct inode *inode = d_inode(path->dentry);
473
+	int err, acc_mode;
474
+
475
+	if (flags & ~(O_ACCMODE | O_LARGEFILE))
476
+		BUG();
477
+
478
+	switch (flags & O_ACCMODE) {
479
+	case O_RDONLY:
480
+		acc_mode = MAY_READ;
481
+		break;
482
+	case O_WRONLY:
483
+		acc_mode = MAY_WRITE;
484
+		break;
485
+	default:
486
+		BUG();
487
+	}
488
+
489
+	err = inode_permission(inode, acc_mode | MAY_OPEN);
490
+	if (err)
491
+		return ERR_PTR(err);
492
+
493
+	/* O_NOATIME is an optimization, don't fail if not permitted */
494
+	if (inode_owner_or_capable(inode))
495
+		flags |= O_NOATIME;
496
+
497
+	return dentry_open(path, flags, current_cred());
497498 }
498499 
499500 /* Caller should hold ovl_inode->lock */
....@@ -536,13 +537,13 @@
536537 
537538 int ovl_copy_up_start(struct dentry *dentry, int flags)
538539 {
539
-	struct ovl_inode *oi = OVL_I(d_inode(dentry));
540
+	struct inode *inode = d_inode(dentry);
540541 	int err;
541542 
542
-	err = mutex_lock_interruptible(&oi->lock);
543
+	err = ovl_inode_lock_interruptible(inode);
543544 	if (!err && ovl_already_copied_up_locked(dentry, flags)) {
544545 		err = 1; /* Already copied up */
545
-		mutex_unlock(&oi->lock);
546
+		ovl_inode_unlock(inode);
546547 	}
547548 
548549 	return err;
....@@ -550,14 +551,14 @@
550551 
551552 void ovl_copy_up_end(struct dentry *dentry)
552553 {
553
-	mutex_unlock(&OVL_I(d_inode(dentry))->lock);
554
+	ovl_inode_unlock(d_inode(dentry));
554555 }
555556 
556
-bool ovl_check_origin_xattr(struct dentry *dentry)
557
+bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry)
557558 {
558559 	ssize_t res;
559560 
560
-	res = ovl_vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0);
561
+	res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_ORIGIN, NULL, 0);
561562 
562563 	/* Zero size value means "copied up but origin unknown" */
563564 	if (res >= 0)
....@@ -566,7 +567,8 @@
566567 	return false;
567568 }
568569 
569
-bool ovl_check_dir_xattr(struct dentry *dentry, const char *name)
570
+bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
571
+			 enum ovl_xattr ox)
570572 {
571573 	ssize_t res;
572574 	char val;
....@@ -574,15 +576,36 @@
574576 	if (!d_is_dir(dentry))
575577 		return false;
576578 
577
-	res = ovl_vfs_getxattr(dentry, name, &val, 1);
579
+	res = ovl_do_getxattr(OVL_FS(sb), dentry, ox, &val, 1);
578580 	if (res == 1 && val == 'y')
579581 		return true;
580582 
581583 	return false;
582584 }
583585 
586
+#define OVL_XATTR_OPAQUE_POSTFIX	"opaque"
587
+#define OVL_XATTR_REDIRECT_POSTFIX	"redirect"
588
+#define OVL_XATTR_ORIGIN_POSTFIX	"origin"
589
+#define OVL_XATTR_IMPURE_POSTFIX	"impure"
590
+#define OVL_XATTR_NLINK_POSTFIX		"nlink"
591
+#define OVL_XATTR_UPPER_POSTFIX		"upper"
592
+#define OVL_XATTR_METACOPY_POSTFIX	"metacopy"
593
+
594
+#define OVL_XATTR_TAB_ENTRY(x) \
595
+	[x] = OVL_XATTR_PREFIX x ## _POSTFIX
596
+
597
+const char *ovl_xattr_table[] = {
598
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_OPAQUE),
599
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_REDIRECT),
600
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_ORIGIN),
601
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_IMPURE),
602
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_NLINK),
603
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_UPPER),
604
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_METACOPY),
605
+};
606
+
584607 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
585
-		       const char *name, const void *value, size_t size,
608
+		       enum ovl_xattr ox, const void *value, size_t size,
586609 		       int xerr)
587610 {
588611 	int err;
....@@ -591,10 +614,10 @@
591614 	if (ofs->noxattr)
592615 		return xerr;
593616 
594
-	err = ovl_do_setxattr(upperdentry, name, value, size, 0);
617
+	err = ovl_do_setxattr(ofs, upperdentry, ox, value, size);
595618 
596619 	if (err == -EOPNOTSUPP) {
597
-		pr_warn("overlayfs: cannot set %s xattr on upper\n", name);
620
+		pr_warn("cannot set %s xattr on upper\n", ovl_xattr(ofs, ox));
598621 		ofs->noxattr = true;
599622 		return xerr;
600623 	}
....@@ -619,21 +642,6 @@
619642 		ovl_set_flag(OVL_IMPURE, d_inode(dentry));
620643 
621644 	return err;
622
-}
623
-
624
-void ovl_set_flag(unsigned long flag, struct inode *inode)
625
-{
626
-	set_bit(flag, &OVL_I(inode)->flags);
627
-}
628
-
629
-void ovl_clear_flag(unsigned long flag, struct inode *inode)
630
-{
631
-	clear_bit(flag, &OVL_I(inode)->flags);
632
-}
633
-
634
-bool ovl_test_flag(unsigned long flag, struct inode *inode)
635
-{
636
-	return test_bit(flag, &OVL_I(inode)->flags);
637645 }
638646 
639647 /**
....@@ -718,7 +726,7 @@
718726 
719727 	inode = d_inode(upperdentry);
720728 	if (!S_ISDIR(inode->i_mode) && inode->i_nlink != 1) {
721
-		pr_warn_ratelimited("overlayfs: cleanup linked index (%pd2, ino=%lu, nlink=%u)\n",
729
+		pr_warn_ratelimited("cleanup linked index (%pd2, ino=%lu, nlink=%u)\n",
722730 				    upperdentry, inode->i_ino, inode->i_nlink);
723731 		/*
724732 		 * We either have a bug with persistent union nlink or a lower
....@@ -741,7 +749,8 @@
741749 		index = NULL;
742750 	} else if (ovl_index_all(dentry->d_sb)) {
743751 		/* Whiteout orphan index to block future open by handle */
744
-		err = ovl_cleanup_and_whiteout(indexdir, dir, index);
752
+		err = ovl_cleanup_and_whiteout(OVL_FS(dentry->d_sb),
753
+					       dir, index);
745754 	} else {
746755 		/* Cleanup orphan index entries */
747756 		err = ovl_cleanup(dir, index);
....@@ -757,7 +766,7 @@
757766 	return;
758767 
759768 fail:
760
-	pr_err("overlayfs: cleanup index of '%pd2' failed (%i)\n", dentry, err);
769
+	pr_err("cleanup index of '%pd2' failed (%i)\n", dentry, err);
761770 	goto out;
762771 }
763772 
....@@ -765,14 +774,14 @@
765774  * Operations that change overlay inode and upper inode nlink need to be
766775  * synchronized with copy up for persistent nlink accounting.
767776  */
768
-int ovl_nlink_start(struct dentry *dentry, bool *locked)
777
+int ovl_nlink_start(struct dentry *dentry)
769778 {
770
-	struct ovl_inode *oi = OVL_I(d_inode(dentry));
779
+	struct inode *inode = d_inode(dentry);
771780 	const struct cred *old_cred;
772781 	int err;
773782 
774
-	if (!d_inode(dentry))
775
-		return 0;
783
+	if (WARN_ON(!inode))
784
+		return -ENOENT;
776785 
777786 	/*
778787 	 * With inodes index is enabled, we store the union overlay nlink
....@@ -794,11 +803,11 @@
794803 			return err;
795804 	}
796805 
797
-	err = mutex_lock_interruptible(&oi->lock);
806
+	err = ovl_inode_lock_interruptible(inode);
798807 	if (err)
799808 		return err;
800809 
801
-	if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, d_inode(dentry)))
810
+	if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, inode))
802811 		goto out;
803812 
804813 	old_cred = ovl_override_creds(dentry->d_sb);
....@@ -809,31 +818,28 @@
809818 	 * value relative to the upper inode nlink in an upper inode xattr.
810819 	 */
811820 	err = ovl_set_nlink_upper(dentry);
812
-	ovl_revert_creds(old_cred);
821
+	ovl_revert_creds(dentry->d_sb, old_cred);
813822 
814823 out:
815824 	if (err)
816
-		mutex_unlock(&oi->lock);
817
-	else
818
-		*locked = true;
825
+		ovl_inode_unlock(inode);
819826 
820827 	return err;
821828 }
822829 
823
-void ovl_nlink_end(struct dentry *dentry, bool locked)
830
+void ovl_nlink_end(struct dentry *dentry)
824831 {
825
-	if (locked) {
826
-		if (ovl_test_flag(OVL_INDEX, d_inode(dentry)) &&
827
-		    d_inode(dentry)->i_nlink == 0) {
828
-			const struct cred *old_cred;
832
+	struct inode *inode = d_inode(dentry);
829833 
830
-			old_cred = ovl_override_creds(dentry->d_sb);
831
-			ovl_cleanup_index(dentry);
832
-			ovl_revert_creds(old_cred);
833
-		}
834
+	if (ovl_test_flag(OVL_INDEX, inode) && inode->i_nlink == 0) {
835
+		const struct cred *old_cred;
834836 
835
-		mutex_unlock(&OVL_I(d_inode(dentry))->lock);
837
+		old_cred = ovl_override_creds(dentry->d_sb);
838
+		ovl_cleanup_index(dentry);
839
+		ovl_revert_creds(dentry->d_sb, old_cred);
836840 	}
841
+
842
+	ovl_inode_unlock(inode);
837843 }
838844 
839845 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir)
....@@ -851,12 +857,12 @@
851857 err_unlock:
852858 	unlock_rename(workdir, upperdir);
853859 err:
854
-	pr_err("overlayfs: failed to lock workdir+upperdir\n");
860
+	pr_err("failed to lock workdir+upperdir\n");
855861 	return -EIO;
856862 }
857863 
858864 /* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */
859
-int ovl_check_metacopy_xattr(struct dentry *dentry)
865
+int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry)
860866 {
861867 	ssize_t res;
862868 
....@@ -864,7 +870,7 @@
864870 	if (!S_ISREG(d_inode(dentry)->i_mode))
865871 		return 0;
866872 
867
-	res = ovl_vfs_getxattr(dentry, OVL_XATTR_METACOPY, NULL, 0);
873
+	res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_METACOPY, NULL, 0);
868874 	if (res < 0) {
869875 		if (res == -ENODATA || res == -EOPNOTSUPP)
870876 			return 0;
....@@ -873,7 +879,7 @@
873879 
874880 	return 1;
875881 out:
876
-	pr_warn_ratelimited("overlayfs: failed to get metacopy (%zi)\n", res);
882
+	pr_warn_ratelimited("failed to get metacopy (%zi)\n", res);
877883 	return res;
878884 }
879885 
....@@ -893,49 +899,27 @@
893899 	return (oe->numlower > 1);
894900 }
895901 
896
-ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
897
-		     size_t padding)
898
-{
899
-	ssize_t res;
900
-	char *buf = NULL;
901
-
902
-	res = ovl_vfs_getxattr(dentry, name, NULL, 0);
903
-	if (res < 0) {
904
-		if (res == -ENODATA || res == -EOPNOTSUPP)
905
-			return -ENODATA;
906
-		goto fail;
907
-	}
908
-
909
-	if (res != 0) {
910
-		buf = kzalloc(res + padding, GFP_KERNEL);
911
-		if (!buf)
912
-			return -ENOMEM;
913
-
914
-		res = ovl_vfs_getxattr(dentry, name, buf, res);
915
-		if (res < 0)
916
-			goto fail;
917
-	}
918
-	*value = buf;
919
-
920
-	return res;
921
-
922
-fail:
923
-	pr_warn_ratelimited("overlayfs: failed to get xattr %s: err=%zi)\n",
924
-			    name, res);
925
-	kfree(buf);
926
-	return res;
927
-}
928
-
929
-char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
902
+char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry,
903
+			     int padding)
930904 {
931905 	int res;
932906 	char *s, *next, *buf = NULL;
933907 
934
-	res = ovl_getxattr(dentry, OVL_XATTR_REDIRECT, &buf, padding + 1);
935
-	if (res == -ENODATA)
908
+	res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_REDIRECT, NULL, 0);
909
+	if (res == -ENODATA || res == -EOPNOTSUPP)
936910 		return NULL;
937911 	if (res < 0)
938
-		return ERR_PTR(res);
912
+		goto fail;
913
+	if (res == 0)
914
+		goto invalid;
915
+
916
+	buf = kzalloc(res + padding + 1, GFP_KERNEL);
917
+	if (!buf)
918
+		return ERR_PTR(-ENOMEM);
919
+
920
+	res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_REDIRECT, buf, res);
921
+	if (res < 0)
922
+		goto fail;
939923 	if (res == 0)
940924 		goto invalid;
941925 
....@@ -952,8 +936,39 @@
952936 
953937 	return buf;
954938 invalid:
955
-	pr_warn_ratelimited("overlayfs: invalid redirect (%s)\n", buf);
939
+	pr_warn_ratelimited("invalid redirect (%s)\n", buf);
956940 	res = -EINVAL;
941
+	goto err_free;
942
+fail:
943
+	pr_warn_ratelimited("failed to get redirect (%i)\n", res);
944
+err_free:
957945 	kfree(buf);
958946 	return ERR_PTR(res);
959947 }
948
+
949
+/*
950
+ * ovl_sync_status() - Check fs sync status for volatile mounts
951
+ *
952
+ * Returns 1 if this is not a volatile mount and a real sync is required.
953
+ *
954
+ * Returns 0 if syncing can be skipped because mount is volatile, and no errors
955
+ * have occurred on the upperdir since the mount.
956
+ *
957
+ * Returns -errno if it is a volatile mount, and the error that occurred since
958
+ * the last mount. If the error code changes, it'll return the latest error
959
+ * code.
960
+ */
961
+
962
+int ovl_sync_status(struct ovl_fs *ofs)
963
+{
964
+	struct vfsmount *mnt;
965
+
966
+	if (ovl_should_sync(ofs))
967
+		return 1;
968
+
969
+	mnt = ovl_upper_mnt(ofs);
970
+	if (!mnt)
971
+		return 0;
972
+
973
+	return errseq_check(&mnt->mnt_sb->s_wb_err, ofs->errseq);
974
+}