Merge tag 'bcachefs-2025-07-03' of git://evilpiepirate.org/bcachefs

Pull bcachefs fixes from Kent Overstreet:
 "The 'opts.casefold_disabled' patch is non critical, but would be a
  6.15 backport; it's to address the casefolding + overlayfs
  incompatibility that was discovvered late.

  It's late because I was hoping that this would be addressed on the
  overlayfs side (and will be in 6.17), but user reports keep coming in
  on this one (lots of people are using docker these days)"

* tag 'bcachefs-2025-07-03' of git://evilpiepirate.org/bcachefs:
  bcachefs: opts.casefold_disabled
  bcachefs: Work around deadlock to btree node rewrites in journal replay
  bcachefs: Fix incorrect transaction restart handling
  bcachefs: fix btree_trans_peek_prev_journal()
  bcachefs: mark invalid_btree_id autofix

13 files changed, 93 insertions, 54 deletions

diff --git a/fs/bcachefs/bcachefs.h b/fs/bcachefs/bcachefs.h
index 8043943cdf6a..ddfacad0f70c 100644
--- a/fs/bcachefs/bcachefs.h
+++ b/fs/bcachefs/bcachefs.h
@@ -863,9 +863,7 @@ struct bch_fs {
 	DARRAY(enum bcachefs_metadata_version)
 				incompat_versions_requested;
 
-#ifdef CONFIG_UNICODE
 	struct unicode_map	*cf_encoding;
-#endif
 
 	struct bch_sb_handle	disk_sb;
 
@@ -1285,4 +1283,13 @@ static inline bool bch2_discard_opt_enabled(struct bch_fs *c, struct bch_dev *ca
 		: ca->mi.discard;
 }
 
+static inline bool bch2_fs_casefold_enabled(struct bch_fs *c)
+{
+#ifdef CONFIG_UNICODE
+	return !c->opts.casefold_disabled;
+#else
+	return false;
+#endif
+}
+
 #endif /* _BCACHEFS_H */
diff --git a/fs/bcachefs/btree_io.c b/fs/bcachefs/btree_io.c
index 08b22bddd747..e874a4357f64 100644
--- a/fs/bcachefs/btree_io.c
+++ b/fs/bcachefs/btree_io.c
@@ -1337,15 +1337,42 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct bch_dev *ca,
 
 	btree_node_reset_sib_u64s(b);
 
-	scoped_guard(rcu)
-		bkey_for_each_ptr(bch2_bkey_ptrs(bkey_i_to_s(&b->key)), ptr) {
-			struct bch_dev *ca2 = bch2_dev_rcu(c, ptr->dev);
-
-			if (!ca2 || ca2->mi.state != BCH_MEMBER_STATE_rw) {
-				set_btree_node_need_rewrite(b);
-				set_btree_node_need_rewrite_degraded(b);
+	/*
+	 * XXX:
+	 *
+	 * We deadlock if too many btree updates require node rewrites while
+	 * we're still in journal replay.
+	 *
+	 * This is because btree node rewrites generate more updates for the
+	 * interior updates (alloc, backpointers), and if those updates touch
+	 * new nodes and generate more rewrites - well, you see the problem.
+	 *
+	 * The biggest cause is that we don't use the btree write buffer (for
+	 * the backpointer updates - this needs some real thought on locking in
+	 * order to fix.
+	 *
+	 * The problem with this workaround (not doing the rewrite for degraded
+	 * nodes in journal replay) is that those degraded nodes persist, and we
+	 * don't want that (this is a real bug when a btree node write completes
+	 * with fewer replicas than we wanted and leaves a degraded node due to
+	 * device _removal_, i.e. the device went away mid write).
+	 *
+	 * It's less of a bug here, but still a problem because we don't yet
+	 * have a way of tracking degraded data - we another index (all
+	 * extents/btree nodes, by replicas entry) in order to fix properly
+	 * (re-replicate degraded data at the earliest possible time).
+	 */
+	if (c->recovery.passes_complete & BIT_ULL(BCH_RECOVERY_PASS_journal_replay)) {
+		scoped_guard(rcu)
+			bkey_for_each_ptr(bch2_bkey_ptrs(bkey_i_to_s(&b->key)), ptr) {
+				struct bch_dev *ca2 = bch2_dev_rcu(c, ptr->dev);
+
+				if (!ca2 || ca2->mi.state != BCH_MEMBER_STATE_rw) {
+					set_btree_node_need_rewrite(b);
+					set_btree_node_need_rewrite_degraded(b);
+				}
 			}
-		}
+	}
 
 	if (!ptr_written) {
 		set_btree_node_need_rewrite(b);
diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index 352f9cd2634f..f8829b667ad3 100644
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -2189,7 +2189,7 @@ void btree_trans_peek_prev_journal(struct btree_trans *trans,
 	struct btree_path *path = btree_iter_path(trans, iter);
 	struct bkey_i *next_journal =
 		bch2_btree_journal_peek_prev(trans, iter, search_key,
-				k->k ? k->k->p : path_l(path)->b->key.k.p);
+				k->k ? k->k->p : path_l(path)->b->data->min_key);
 
 	if (next_journal) {
 		iter->k = next_journal->k;
diff --git a/fs/bcachefs/dirent.c b/fs/bcachefs/dirent.c
index 300f7cc8abdf..a18d0f78704d 100644
--- a/fs/bcachefs/dirent.c
+++ b/fs/bcachefs/dirent.c
@@ -18,7 +18,9 @@ int bch2_casefold(struct btree_trans *trans, const struct bch_hash_info *info,
 {
 	*out_cf = (struct qstr) QSTR_INIT(NULL, 0);
 
-#ifdef CONFIG_UNICODE
+	if (!bch2_fs_casefold_enabled(trans->c))
+		return -EOPNOTSUPP;
+
 	unsigned char *buf = bch2_trans_kmalloc(trans, BCH_NAME_MAX + 1);
 	int ret = PTR_ERR_OR_ZERO(buf);
 	if (ret)
@@ -30,9 +32,6 @@ int bch2_casefold(struct btree_trans *trans, const struct bch_hash_info *info,
 
 	*out_cf = (struct qstr) QSTR_INIT(buf, ret);
 	return 0;
-#else
-	return -EOPNOTSUPP;
-#endif
 }
 
 static unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent d)
@@ -231,7 +230,8 @@ void bch2_dirent_to_text(struct printbuf *out, struct bch_fs *c, struct bkey_s_c
 	prt_printf(out, " type %s", bch2_d_type_str(d.v->d_type));
 }
 
-int bch2_dirent_init_name(struct bkey_i_dirent *dirent,
+int bch2_dirent_init_name(struct bch_fs *c,
+			  struct bkey_i_dirent *dirent,
 			  const struct bch_hash_info *hash_info,
 			  const struct qstr *name,
 			  const struct qstr *cf_name)
@@ -251,7 +251,9 @@ int bch2_dirent_init_name(struct bkey_i_dirent *dirent,
 		       offsetof(struct bch_dirent, d_name) -
 		       name->len);
 	} else {
-#ifdef CONFIG_UNICODE
+		if (!bch2_fs_casefold_enabled(c))
+			return -EOPNOTSUPP;
+
 		memcpy(&dirent->v.d_cf_name_block.d_names[0], name->name, name->len);
 
 		char *cf_out = &dirent->v.d_cf_name_block.d_names[name->len];
@@ -277,9 +279,6 @@ int bch2_dirent_init_name(struct bkey_i_dirent *dirent,
 		dirent->v.d_cf_name_block.d_cf_name_len = cpu_to_le16(cf_len);
 
 		EBUG_ON(bch2_dirent_get_casefold_name(dirent_i_to_s_c(dirent)).len != cf_len);
-#else
-	return -EOPNOTSUPP;
-#endif
 	}
 
 	unsigned u64s = dirent_val_u64s(name->len, cf_len);
@@ -313,7 +312,7 @@ struct bkey_i_dirent *bch2_dirent_create_key(struct btree_trans *trans,
 	dirent->v.d_type = type;
 	dirent->v.d_unused = 0;
 
-	int ret = bch2_dirent_init_name(dirent, hash_info, name, cf_name);
+	int ret = bch2_dirent_init_name(trans->c, dirent, hash_info, name, cf_name);
 	if (ret)
 		return ERR_PTR(ret);
 
diff --git a/fs/bcachefs/dirent.h b/fs/bcachefs/dirent.h
index 70fb0b581221..1e17199cc5c7 100644
--- a/fs/bcachefs/dirent.h
+++ b/fs/bcachefs/dirent.h
@@ -59,7 +59,8 @@ static inline void dirent_copy_target(struct bkey_i_dirent *dst,
 	dst->v.d_type = src.v->d_type;
 }
 
-int bch2_dirent_init_name(struct bkey_i_dirent *,
+int bch2_dirent_init_name(struct bch_fs *,
+			  struct bkey_i_dirent *,
 			  const struct bch_hash_info *,
 			  const struct qstr *,
 			  const struct qstr *);
diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index db24a76563f8..e54e4f255b22 100644
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -722,7 +722,6 @@ static struct dentry *bch2_lookup(struct inode *vdir, struct dentry *dentry,
 	if (IS_ERR(inode))
 		inode = NULL;
 
-#ifdef CONFIG_UNICODE
 	if (!inode && IS_CASEFOLDED(vdir)) {
 		/*
 		 * Do not cache a negative dentry in casefolded directories
@@ -737,7 +736,6 @@ static struct dentry *bch2_lookup(struct inode *vdir, struct dentry *dentry,
 		 */
 		return NULL;
 	}
-#endif
 
 	return d_splice_alias(&inode->v, dentry);
 }
@@ -2566,9 +2564,10 @@ got_sb:
 	sb->s_shrink->seeks = 0;
 
 #ifdef CONFIG_UNICODE
-	sb->s_encoding = c->cf_encoding;
-#endif
+	if (bch2_fs_casefold_enabled(c))
+		sb->s_encoding = c->cf_encoding;
 	generic_set_sb_d_ops(sb);
+#endif
 
 	vinode = bch2_vfs_inode_get(c, BCACHEFS_ROOT_SUBVOL_INUM);
 	ret = PTR_ERR_OR_ZERO(vinode);
diff --git a/fs/bcachefs/fsck.c b/fs/bcachefs/fsck.c
index 9920f1affc5b..dbf161e4311a 100644
--- a/fs/bcachefs/fsck.c
+++ b/fs/bcachefs/fsck.c
@@ -2302,9 +2302,7 @@ static int check_dirent(struct btree_trans *trans, struct btree_iter *iter,
 		*hash_info = bch2_hash_info_init(c, &i->inode);
 	dir->first_this_inode = false;
 
-#ifdef CONFIG_UNICODE
 	hash_info->cf_encoding = bch2_inode_casefold(c, &i->inode) ? c->cf_encoding : NULL;
-#endif
 
 	ret = bch2_str_hash_check_key(trans, s, &bch2_dirent_hash_desc, hash_info,
 				      iter, k, need_second_pass);
@@ -2819,7 +2817,7 @@ static int check_path_loop(struct btree_trans *trans, struct bkey_s_c inode_k)
 				ret = remove_backpointer(trans, &inode);
 				bch_err_msg(c, ret, "removing dirent");
 				if (ret)
-					break;
+					goto out;
 
 				ret = reattach_inode(trans, &inode);
 				bch_err_msg(c, ret, "reattaching inode %llu", inode.bi_inum);
diff --git a/fs/bcachefs/inode.c b/fs/bcachefs/inode.c
index 53e5dc1f6ac1..ef4cc7395b86 100644
--- a/fs/bcachefs/inode.c
+++ b/fs/bcachefs/inode.c
@@ -1265,7 +1265,14 @@ int bch2_inode_set_casefold(struct btree_trans *trans, subvol_inum inum,
 {
 	struct bch_fs *c = trans->c;
 
-#ifdef CONFIG_UNICODE
+#ifndef CONFIG_UNICODE
+	bch_err(c, "Cannot use casefolding on a kernel without CONFIG_UNICODE");
+	return -EOPNOTSUPP;
+#endif
+
+	if (c->opts.casefold_disabled)
+		return -EOPNOTSUPP;
+
 	int ret = 0;
 	/* Not supported on individual files. */
 	if (!S_ISDIR(bi->bi_mode))
@@ -1289,10 +1296,6 @@ int bch2_inode_set_casefold(struct btree_trans *trans, subvol_inum inum,
 	bi->bi_fields_set |= BIT(Inode_opt_casefold);
 
 	return bch2_maybe_propagate_has_case_insensitive(trans, inum, bi);
-#else
-	bch_err(c, "Cannot use casefolding on a kernel without CONFIG_UNICODE");
-	return -EOPNOTSUPP;
-#endif
 }
 
 static noinline int __bch2_inode_rm_snapshot(struct btree_trans *trans, u64 inum, u32 snapshot)
diff --git a/fs/bcachefs/opts.h b/fs/bcachefs/opts.h
index b0a76bd6d6f5..63f8e254495c 100644
--- a/fs/bcachefs/opts.h
+++ b/fs/bcachefs/opts.h
@@ -234,6 +234,11 @@ enum fsck_err_opts {
 	  OPT_BOOL(),							\
 	  BCH_SB_CASEFOLD,		false,				\
 	  NULL,		"Dirent lookups are casefolded")		\
+	x(casefold_disabled,			u8,			\
+	  OPT_FS|OPT_MOUNT,						\
+	  OPT_BOOL(),							\
+	  BCH2_NO_SB_OPT,		false,				\
+	  NULL,		"Disable casefolding filesystem wide")		\
 	x(inodes_32bit,			u8,				\
 	  OPT_FS|OPT_INODE|OPT_FORMAT|OPT_MOUNT|OPT_RUNTIME,		\
 	  OPT_BOOL(),							\
diff --git a/fs/bcachefs/sb-errors_format.h b/fs/bcachefs/sb-errors_format.h
index 0641fb634bd4..d154b7651d28 100644
--- a/fs/bcachefs/sb-errors_format.h
+++ b/fs/bcachefs/sb-errors_format.h
@@ -314,7 +314,7 @@ enum bch_fsck_flags {
 	x(accounting_mismatch,					272,	FSCK_AUTOFIX)	\
 	x(accounting_replicas_not_marked,			273,	0)		\
 	x(accounting_to_invalid_device,				289,	0)		\
-	x(invalid_btree_id,					274,	0)		\
+	x(invalid_btree_id,					274,	FSCK_AUTOFIX)		\
 	x(alloc_key_io_time_bad,				275,	0)		\
 	x(alloc_key_fragmentation_lru_wrong,			276,	FSCK_AUTOFIX)	\
 	x(accounting_key_junk_at_end,				277,	FSCK_AUTOFIX)	\
diff --git a/fs/bcachefs/str_hash.c b/fs/bcachefs/str_hash.c
index 71b735a85026..3e9f59226bdf 100644
--- a/fs/bcachefs/str_hash.c
+++ b/fs/bcachefs/str_hash.c
@@ -38,6 +38,7 @@ static int bch2_fsck_rename_dirent(struct btree_trans *trans,
 				   struct bkey_s_c_dirent old,
 				   bool *updated_before_k_pos)
 {
+	struct bch_fs *c = trans->c;
 	struct qstr old_name = bch2_dirent_get_name(old);
 	struct bkey_i_dirent *new = bch2_trans_kmalloc(trans, BKEY_U64s_MAX * sizeof(u64));
 	int ret = PTR_ERR_OR_ZERO(new);
@@ -60,7 +61,7 @@ static int bch2_fsck_rename_dirent(struct btree_trans *trans,
 					sprintf(renamed_buf, "%.*s.fsck_renamed-%u",
 						old_name.len, old_name.name, i));
 
-		ret = bch2_dirent_init_name(new, hash_info, &renamed_name, NULL);
+		ret = bch2_dirent_init_name(c, new, hash_info, &renamed_name, NULL);
 		if (ret)
 			return ret;
 
@@ -79,7 +80,7 @@ static int bch2_fsck_rename_dirent(struct btree_trans *trans,
 	}
 
 	ret = ret ?: bch2_fsck_update_backpointers(trans, s, desc, hash_info, &new->k_i);
-	bch_err_fn(trans->c, ret);
+	bch_err_fn(c, ret);
 	return ret;
 }
 
diff --git a/fs/bcachefs/str_hash.h b/fs/bcachefs/str_hash.h
index 79d51aef70aa..8979ac2d7a3b 100644
--- a/fs/bcachefs/str_hash.h
+++ b/fs/bcachefs/str_hash.h
@@ -48,9 +48,7 @@ bch2_hash_info_init(struct bch_fs *c, const struct bch_inode_unpacked *bi)
 	struct bch_hash_info info = {
 		.inum_snapshot	= bi->bi_snapshot,
 		.type		= INODE_STR_HASH(bi),
-#ifdef CONFIG_UNICODE
 		.cf_encoding	= bch2_inode_casefold(c, bi) ? c->cf_encoding : NULL,
-#endif
 		.siphash_key	= { .k0 = bi->bi_hash_seed }
 	};
 
diff --git a/fs/bcachefs/super.c b/fs/bcachefs/super.c
index 69c097ff54e7..c46b1053a02c 100644
--- a/fs/bcachefs/super.c
+++ b/fs/bcachefs/super.c
@@ -1025,15 +1025,17 @@ static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts *opts,
 	}
 
 #ifdef CONFIG_UNICODE
-	/* Default encoding until we can potentially have more as an option. */
-	c->cf_encoding = utf8_load(BCH_FS_DEFAULT_UTF8_ENCODING);
-	if (IS_ERR(c->cf_encoding)) {
-		printk(KERN_ERR "Cannot load UTF-8 encoding for filesystem. Version: %u.%u.%u",
-			unicode_major(BCH_FS_DEFAULT_UTF8_ENCODING),
-			unicode_minor(BCH_FS_DEFAULT_UTF8_ENCODING),
-			unicode_rev(BCH_FS_DEFAULT_UTF8_ENCODING));
-		ret = -EINVAL;
-		goto err;
+	if (bch2_fs_casefold_enabled(c)) {
+		/* Default encoding until we can potentially have more as an option. */
+		c->cf_encoding = utf8_load(BCH_FS_DEFAULT_UTF8_ENCODING);
+		if (IS_ERR(c->cf_encoding)) {
+			printk(KERN_ERR "Cannot load UTF-8 encoding for filesystem. Version: %u.%u.%u",
+			       unicode_major(BCH_FS_DEFAULT_UTF8_ENCODING),
+			       unicode_minor(BCH_FS_DEFAULT_UTF8_ENCODING),
+			       unicode_rev(BCH_FS_DEFAULT_UTF8_ENCODING));
+			ret = -EINVAL;
+			goto err;
+		}
 	}
 #else
 	if (c->sb.features & BIT_ULL(BCH_FEATURE_casefolding)) {
@@ -1160,12 +1162,11 @@ int bch2_fs_start(struct bch_fs *c)
 
 	print_mount_opts(c);
 
-#ifdef CONFIG_UNICODE
-	bch_info(c, "Using encoding defined by superblock: utf8-%u.%u.%u",
-		 unicode_major(BCH_FS_DEFAULT_UTF8_ENCODING),
-		 unicode_minor(BCH_FS_DEFAULT_UTF8_ENCODING),
-		 unicode_rev(BCH_FS_DEFAULT_UTF8_ENCODING));
-#endif
+	if (c->cf_encoding)
+		bch_info(c, "Using encoding defined by superblock: utf8-%u.%u.%u",
+			 unicode_major(BCH_FS_DEFAULT_UTF8_ENCODING),
+			 unicode_minor(BCH_FS_DEFAULT_UTF8_ENCODING),
+			 unicode_rev(BCH_FS_DEFAULT_UTF8_ENCODING));
 
 	if (!bch2_fs_may_start(c))
 		return bch_err_throw(c, insufficient_devices_to_start);