diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index d09d622..35e3071 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -1616,25 +1616,29 @@ int btrfs_compress_heuristic(struct btrfs_inode *inode, u64 start, u64 end)
 }
 
 /*
- * Convert the compression suffix (eg. after "zlib" starting with ":") to
- * level, unrecognized string will set the default level. Negative level
- * numbers are allowed.
+ * Convert the compression suffix (eg. after "zlib" starting with ":") to level.
+ *
+ * If the resulting level exceeds the algo's supported levels, it will be clamped.
+ *
+ * Return <0 if no valid string can be found.
+ * Return 0 if everything is fine.
  */
-int btrfs_compress_str2level(unsigned int type, const char *str)
+int btrfs_compress_str2level(unsigned int type, const char *str, int *level_ret)
 {
 	int level = 0;
 	int ret;
 
-	if (!type)
+	if (!type) {
+		*level_ret = btrfs_compress_set_level(type, level);
 		return 0;
+	}
 
 	if (str[0] == ':') {
 		ret = kstrtoint(str + 1, 10, &level);
 		if (ret)
-			level = 0;
+			return ret;
 	}
 
-	level = btrfs_compress_set_level(type, level);
-
-	return level;
+	*level_ret = btrfs_compress_set_level(type, level);
+	return 0;
 }
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index 1b38e70..7b41b2b 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -102,7 +102,7 @@ void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered,
 				   bool writeback);
 void btrfs_submit_compressed_read(struct btrfs_bio *bbio);
 
-int btrfs_compress_str2level(unsigned int type, const char *str);
+int btrfs_compress_str2level(unsigned int type, const char *str, int *level_ret);
 
 struct folio *btrfs_alloc_compr_folio(void);
 void btrfs_free_compr_folio(struct folio *folio);
diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c
index 3871c3a..9f1858b 100644
--- a/fs/btrfs/ref-verify.c
+++ b/fs/btrfs/ref-verify.c
@@ -980,11 +980,18 @@ int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
 	if (!btrfs_test_opt(fs_info, REF_VERIFY))
 		return 0;
 
+	extent_root = btrfs_extent_root(fs_info, 0);
+	/* If the extent tree is damaged we cannot ignore it (IGNOREBADROOTS). */
+	if (IS_ERR(extent_root)) {
+		btrfs_warn(fs_info, "ref-verify: extent tree not available, disabling");
+		btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
+		return 0;
+	}
+
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
 
-	extent_root = btrfs_extent_root(fs_info, 0);
 	eb = btrfs_read_lock_root_node(extent_root);
 	level = btrfs_header_level(eb);
 	path->nodes[level] = eb;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index df1f6cc..b06b8f3 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -276,6 +276,7 @@ static int btrfs_parse_compress(struct btrfs_fs_context *ctx,
 				const struct fs_parameter *param, int opt)
 {
 	const char *string = param->string;
+	int ret;
 
 	/*
 	 * Provide the same semantics as older kernels that don't use fs
@@ -294,15 +295,19 @@ static int btrfs_parse_compress(struct btrfs_fs_context *ctx,
 		btrfs_clear_opt(ctx->mount_opt, NODATASUM);
 	} else if (btrfs_match_compress_type(string, "zlib", true)) {
 		ctx->compress_type = BTRFS_COMPRESS_ZLIB;
-		ctx->compress_level = btrfs_compress_str2level(BTRFS_COMPRESS_ZLIB,
-							       string + 4);
+		ret = btrfs_compress_str2level(BTRFS_COMPRESS_ZLIB, string + 4,
+					       &ctx->compress_level);
+		if (ret < 0)
+			goto error;
 		btrfs_set_opt(ctx->mount_opt, COMPRESS);
 		btrfs_clear_opt(ctx->mount_opt, NODATACOW);
 		btrfs_clear_opt(ctx->mount_opt, NODATASUM);
 	} else if (btrfs_match_compress_type(string, "lzo", true)) {
 		ctx->compress_type = BTRFS_COMPRESS_LZO;
-		ctx->compress_level = btrfs_compress_str2level(BTRFS_COMPRESS_LZO,
-							       string + 3);
+		ret = btrfs_compress_str2level(BTRFS_COMPRESS_LZO, string + 3,
+					       &ctx->compress_level);
+		if (ret < 0)
+			goto error;
 		if (string[3] == ':' && string[4])
 			btrfs_warn(NULL, "Compression level ignored for LZO");
 		btrfs_set_opt(ctx->mount_opt, COMPRESS);
@@ -310,8 +315,10 @@ static int btrfs_parse_compress(struct btrfs_fs_context *ctx,
 		btrfs_clear_opt(ctx->mount_opt, NODATASUM);
 	} else if (btrfs_match_compress_type(string, "zstd", true)) {
 		ctx->compress_type = BTRFS_COMPRESS_ZSTD;
-		ctx->compress_level = btrfs_compress_str2level(BTRFS_COMPRESS_ZSTD,
-							       string + 4);
+		ret = btrfs_compress_str2level(BTRFS_COMPRESS_ZSTD, string + 4,
+					       &ctx->compress_level);
+		if (ret < 0)
+			goto error;
 		btrfs_set_opt(ctx->mount_opt, COMPRESS);
 		btrfs_clear_opt(ctx->mount_opt, NODATACOW);
 		btrfs_clear_opt(ctx->mount_opt, NODATASUM);
@@ -322,10 +329,14 @@ static int btrfs_parse_compress(struct btrfs_fs_context *ctx,
 		btrfs_clear_opt(ctx->mount_opt, COMPRESS);
 		btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
 	} else {
-		btrfs_err(NULL, "unrecognized compression value %s", string);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto error;
 	}
 	return 0;
+error:
+	btrfs_err(NULL, "failed to parse compression option '%s'", string);
+	return ret;
+
 }
 
 static int btrfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index 0f556f4..a997c7c 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -1756,10 +1756,10 @@ static int check_inode_ref(struct extent_buffer *leaf,
 	while (ptr < end) {
 		u16 namelen;
 
-		if (unlikely(ptr + sizeof(iref) > end)) {
+		if (unlikely(ptr + sizeof(*iref) > end)) {
 			inode_ref_err(leaf, slot,
 			"inode ref overflow, ptr %lu end %lu inode_ref_size %zu",
-				ptr, end, sizeof(iref));
+				ptr, end, sizeof(*iref));
 			return -EUCLEAN;
 		}