diff --git a/fs/bcachefs/bcachefs_format.h b/fs/bcachefs/bcachefs_format.h
index 8114ad9a3fe6..a6cc817ccd87 100644
--- a/fs/bcachefs/bcachefs_format.h
+++ b/fs/bcachefs/bcachefs_format.h
@@ -690,7 +690,8 @@ struct bch_sb_field_ext {
 	x(cached_backpointers,		BCH_VERSION(1, 21))		\
 	x(stripe_backpointers,		BCH_VERSION(1, 22))		\
 	x(stripe_lru,			BCH_VERSION(1, 23))		\
-	x(casefolding,			BCH_VERSION(1, 24))
+	x(casefolding,			BCH_VERSION(1, 24))		\
+	x(extent_flags,			BCH_VERSION(1, 25))
 
 enum bcachefs_metadata_version {
 	bcachefs_metadata_version_min = 9,
diff --git a/fs/bcachefs/errcode.h b/fs/bcachefs/errcode.h
index 9e19bc37aa72..0d9a8198e95e 100644
--- a/fs/bcachefs/errcode.h
+++ b/fs/bcachefs/errcode.h
@@ -271,6 +271,7 @@
 	x(EIO,				mark_stripe)				\
 	x(EIO,				stripe_reconstruct)			\
 	x(EIO,				key_type_error)				\
+	x(EIO,				extent_poisened)			\
 	x(EIO,				no_device_to_read_from)			\
 	x(EIO,				missing_indirect_extent)		\
 	x(EIO,				invalidate_stripe_to_dev)		\
diff --git a/fs/bcachefs/extents.c b/fs/bcachefs/extents.c
index ec653109de5b..d9bdf433c118 100644
--- a/fs/bcachefs/extents.c
+++ b/fs/bcachefs/extents.c
@@ -28,6 +28,13 @@
 #include "trace.h"
 #include "util.h"
 
+static const char * const bch2_extent_flags_strs[] = {
+#define x(n, v)	[BCH_EXTENT_FLAG_##n] = #n,
+	BCH_EXTENT_FLAGS()
+#undef x
+	NULL,
+};
+
 static unsigned bch2_crc_field_size_max[] = {
 	[BCH_EXTENT_ENTRY_crc32] = CRC32_SIZE_MAX,
 	[BCH_EXTENT_ENTRY_crc64] = CRC64_SIZE_MAX,
@@ -127,6 +134,9 @@ int bch2_bkey_pick_read_device(struct bch_fs *c, struct bkey_s_c k,
 	if (k.k->type == KEY_TYPE_error)
 		return -BCH_ERR_key_type_error;
 
+	if (bch2_bkey_extent_ptrs_flags(ptrs) & BIT_ULL(BCH_EXTENT_FLAG_poisoned))
+		return -BCH_ERR_extent_poisened;
+
 	rcu_read_lock();
 	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 		/*
@@ -1225,6 +1235,10 @@ void bch2_bkey_ptrs_to_text(struct printbuf *out, struct bch_fs *c,
 			bch2_extent_rebalance_to_text(out, c, &entry->rebalance);
 			break;
 
+		case BCH_EXTENT_ENTRY_flags:
+			prt_bitflags(out, bch2_extent_flags_strs, entry->flags.flags);
+			break;
+
 		default:
 			prt_printf(out, "(invalid extent entry %.16llx)", *((u64 *) entry));
 			return;
@@ -1386,6 +1400,11 @@ int bch2_bkey_ptrs_validate(struct bch_fs *c, struct bkey_s_c k,
 #endif
 			break;
 		}
+		case BCH_EXTENT_ENTRY_flags:
+			bkey_fsck_err_on(entry != ptrs.start,
+					 c, extent_flags_not_at_start,
+					 "extent flags entry not at start");
+			break;
 		}
 	}
 
@@ -1452,6 +1471,28 @@ void bch2_ptr_swab(struct bkey_s k)
 	}
 }
 
+int bch2_bkey_extent_flags_set(struct bch_fs *c, struct bkey_i *k, u64 flags)
+{
+	int ret = bch2_request_incompat_feature(c, bcachefs_metadata_version_extent_flags);
+	if (ret)
+		return ret;
+
+	struct bkey_ptrs ptrs = bch2_bkey_ptrs(bkey_i_to_s(k));
+
+	if (ptrs.start != ptrs.end &&
+	    extent_entry_type(ptrs.start) == BCH_EXTENT_ENTRY_flags) {
+		ptrs.start->flags.flags = flags;
+	} else {
+		struct bch_extent_flags f = {
+			.type	= BIT(BCH_EXTENT_ENTRY_flags),
+			.flags	= flags,
+		};
+		__extent_entry_insert(k, ptrs.start, (union bch_extent_entry *) &f);
+	}
+
+	return 0;
+}
+
 /* Generic extent code: */
 
 int bch2_cut_front_s(struct bpos where, struct bkey_s k)
@@ -1497,8 +1538,8 @@ int bch2_cut_front_s(struct bpos where, struct bkey_s k)
 				entry->crc128.offset += sub;
 				break;
 			case BCH_EXTENT_ENTRY_stripe_ptr:
-				break;
 			case BCH_EXTENT_ENTRY_rebalance:
+			case BCH_EXTENT_ENTRY_flags:
 				break;
 			}
 
diff --git a/fs/bcachefs/extents.h b/fs/bcachefs/extents.h
index ed160aaa9546..c50c4f353bab 100644
--- a/fs/bcachefs/extents.h
+++ b/fs/bcachefs/extents.h
@@ -753,4 +753,19 @@ static inline void bch2_key_resize(struct bkey *k, unsigned new_size)
 	k->size = new_size;
 }
 
+static inline u64 bch2_bkey_extent_ptrs_flags(struct bkey_ptrs_c ptrs)
+{
+	if (ptrs.start != ptrs.end &&
+	    extent_entry_type(ptrs.start) == BCH_EXTENT_ENTRY_flags)
+		return ptrs.start->flags.flags;
+	return 0;
+}
+
+static inline u64 bch2_bkey_extent_flags(struct bkey_s_c k)
+{
+	return bch2_bkey_extent_ptrs_flags(bch2_bkey_ptrs_c(k));
+}
+
+int bch2_bkey_extent_flags_set(struct bch_fs *, struct bkey_i *, u64);
+
 #endif /* _BCACHEFS_EXTENTS_H */
diff --git a/fs/bcachefs/extents_format.h b/fs/bcachefs/extents_format.h
index c198dfc376d6..74c0252cbd98 100644
--- a/fs/bcachefs/extents_format.h
+++ b/fs/bcachefs/extents_format.h
@@ -79,8 +79,9 @@
 	x(crc64,		2)		\
 	x(crc128,		3)		\
 	x(stripe_ptr,		4)		\
-	x(rebalance,		5)
-#define BCH_EXTENT_ENTRY_MAX	6
+	x(rebalance,		5)		\
+	x(flags,		6)
+#define BCH_EXTENT_ENTRY_MAX	7
 
 enum bch_extent_entry_type {
 #define x(f, n) BCH_EXTENT_ENTRY_##f = n,
@@ -201,6 +202,25 @@ struct bch_extent_stripe_ptr {
 #endif
 };
 
+#define BCH_EXTENT_FLAGS()		\
+	x(poisoned,		0)
+
+enum bch_extent_flags_e {
+#define x(n, v)	BCH_EXTENT_FLAG_##n = v,
+	BCH_EXTENT_FLAGS()
+#undef x
+};
+
+struct bch_extent_flags {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	__u64			type:7,
+				flags:57;
+#elif defined (__BIG_ENDIAN_BITFIELD)
+	__u64			flags:57,
+				type:7;
+#endif
+};
+
 /* bch_extent_rebalance: */
 #include "rebalance_format.h"
 
diff --git a/fs/bcachefs/sb-errors_format.h b/fs/bcachefs/sb-errors_format.h
index cdafd877b8a1..67455beb8358 100644
--- a/fs/bcachefs/sb-errors_format.h
+++ b/fs/bcachefs/sb-errors_format.h
@@ -179,6 +179,7 @@ enum bch_fsck_flags {
 	x(ptr_crc_redundant,					160,	0)		\
 	x(ptr_crc_nonce_mismatch,				162,	0)		\
 	x(ptr_stripe_redundant,					163,	0)		\
+	x(extent_flags_not_at_start,				306,	0)		\
 	x(reservation_key_nr_replicas_invalid,			164,	0)		\
 	x(reflink_v_refcount_wrong,				165,	FSCK_AUTOFIX)	\
 	x(reflink_v_pos_bad,					292,	0)		\
@@ -316,7 +317,7 @@ enum bch_fsck_flags {
 	x(directory_size_mismatch,				303,	FSCK_AUTOFIX)	\
 	x(dirent_cf_name_too_big,				304,	0)		\
 	x(dirent_stray_data_after_cf_name,			305,	0)		\
-	x(MAX,							306,	0)
+	x(MAX,							307,	0)
 
 enum bch_sb_error_id {
 #define x(t, n, ...) BCH_FSCK_ERR_##t = n,