Adding upstream version 6.7.7.upstream/6.7.7

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1511 insertions, 0 deletions

diff --git a/fs/bcachefs/extents.c b/fs/bcachefs/extents.c
new file mode 100644
index 0000000000..9d8afcb597
--- /dev/null
+++ b/fs/bcachefs/extents.c
@@ -0,0 +1,1511 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2010 Kent Overstreet <kent.overstreet@gmail.com>
+ *
+ * Code for managing the extent btree and dynamically updating the writeback
+ * dirty sector count.
+ */
+
+#include "bcachefs.h"
+#include "bkey_methods.h"
+#include "btree_gc.h"
+#include "btree_io.h"
+#include "btree_iter.h"
+#include "buckets.h"
+#include "checksum.h"
+#include "compress.h"
+#include "debug.h"
+#include "disk_groups.h"
+#include "error.h"
+#include "extents.h"
+#include "inode.h"
+#include "journal.h"
+#include "replicas.h"
+#include "super.h"
+#include "super-io.h"
+#include "trace.h"
+#include "util.h"
+
+static unsigned bch2_crc_field_size_max[] = {
+	[BCH_EXTENT_ENTRY_crc32] = CRC32_SIZE_MAX,
+	[BCH_EXTENT_ENTRY_crc64] = CRC64_SIZE_MAX,
+	[BCH_EXTENT_ENTRY_crc128] = CRC128_SIZE_MAX,
+};
+
+static void bch2_extent_crc_pack(union bch_extent_crc *,
+				 struct bch_extent_crc_unpacked,
+				 enum bch_extent_entry_type);
+
+static struct bch_dev_io_failures *dev_io_failures(struct bch_io_failures *f,
+						   unsigned dev)
+{
+	struct bch_dev_io_failures *i;
+
+	for (i = f->devs; i < f->devs + f->nr; i++)
+		if (i->dev == dev)
+			return i;
+
+	return NULL;
+}
+
+void bch2_mark_io_failure(struct bch_io_failures *failed,
+			  struct extent_ptr_decoded *p)
+{
+	struct bch_dev_io_failures *f = dev_io_failures(failed, p->ptr.dev);
+
+	if (!f) {
+		BUG_ON(failed->nr >= ARRAY_SIZE(failed->devs));
+
+		f = &failed->devs[failed->nr++];
+		f->dev		= p->ptr.dev;
+		f->idx		= p->idx;
+		f->nr_failed	= 1;
+		f->nr_retries	= 0;
+	} else if (p->idx != f->idx) {
+		f->idx		= p->idx;
+		f->nr_failed	= 1;
+		f->nr_retries	= 0;
+	} else {
+		f->nr_failed++;
+	}
+}
+
+/*
+ * returns true if p1 is better than p2:
+ */
+static inline bool ptr_better(struct bch_fs *c,
+			      const struct extent_ptr_decoded p1,
+			      const struct extent_ptr_decoded p2)
+{
+	if (likely(!p1.idx && !p2.idx)) {
+		struct bch_dev *dev1 = bch_dev_bkey_exists(c, p1.ptr.dev);
+		struct bch_dev *dev2 = bch_dev_bkey_exists(c, p2.ptr.dev);
+
+		u64 l1 = atomic64_read(&dev1->cur_latency[READ]);
+		u64 l2 = atomic64_read(&dev2->cur_latency[READ]);
+
+		/* Pick at random, biased in favor of the faster device: */
+
+		return bch2_rand_range(l1 + l2) > l1;
+	}
+
+	if (bch2_force_reconstruct_read)
+		return p1.idx > p2.idx;
+
+	return p1.idx < p2.idx;
+}
+
+/*
+ * This picks a non-stale pointer, preferably from a device other than @avoid.
+ * Avoid can be NULL, meaning pick any. If there are no non-stale pointers to
+ * other devices, it will still pick a pointer from avoid.
+ */
+int bch2_bkey_pick_read_device(struct bch_fs *c, struct bkey_s_c k,
+			       struct bch_io_failures *failed,
+			       struct extent_ptr_decoded *pick)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+	struct extent_ptr_decoded p;
+	struct bch_dev_io_failures *f;
+	struct bch_dev *ca;
+	int ret = 0;
+
+	if (k.k->type == KEY_TYPE_error)
+		return -EIO;
+
+	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
+		/*
+		 * Unwritten extent: no need to actually read, treat it as a
+		 * hole and return 0s:
+		 */
+		if (p.ptr.unwritten)
+			return 0;
+
+		ca = bch_dev_bkey_exists(c, p.ptr.dev);
+
+		/*
+		 * If there are any dirty pointers it's an error if we can't
+		 * read:
+		 */
+		if (!ret && !p.ptr.cached)
+			ret = -EIO;
+
+		if (p.ptr.cached && ptr_stale(ca, &p.ptr))
+			continue;
+
+		f = failed ? dev_io_failures(failed, p.ptr.dev) : NULL;
+		if (f)
+			p.idx = f->nr_failed < f->nr_retries
+				? f->idx
+				: f->idx + 1;
+
+		if (!p.idx &&
+		    !bch2_dev_is_readable(ca))
+			p.idx++;
+
+		if (bch2_force_reconstruct_read &&
+		    !p.idx && p.has_ec)
+			p.idx++;
+
+		if (p.idx >= (unsigned) p.has_ec + 1)
+			continue;
+
+		if (ret > 0 && !ptr_better(c, p, *pick))
+			continue;
+
+		*pick = p;
+		ret = 1;
+	}
+
+	return ret;
+}
+
+/* KEY_TYPE_btree_ptr: */
+
+int bch2_btree_ptr_invalid(struct bch_fs *c, struct bkey_s_c k,
+			   enum bkey_invalid_flags flags,
+			   struct printbuf *err)
+{
+	int ret = 0;
+
+	bkey_fsck_err_on(bkey_val_u64s(k.k) > BCH_REPLICAS_MAX, c, err,
+			 btree_ptr_val_too_big,
+			 "value too big (%zu > %u)", bkey_val_u64s(k.k), BCH_REPLICAS_MAX);
+
+	ret = bch2_bkey_ptrs_invalid(c, k, flags, err);
+fsck_err:
+	return ret;
+}
+
+void bch2_btree_ptr_to_text(struct printbuf *out, struct bch_fs *c,
+			    struct bkey_s_c k)
+{
+	bch2_bkey_ptrs_to_text(out, c, k);
+}
+
+int bch2_btree_ptr_v2_invalid(struct bch_fs *c, struct bkey_s_c k,
+			      enum bkey_invalid_flags flags,
+			      struct printbuf *err)
+{
+	int ret = 0;
+
+	bkey_fsck_err_on(bkey_val_u64s(k.k) > BKEY_BTREE_PTR_VAL_U64s_MAX, c, err,
+			 btree_ptr_v2_val_too_big,
+			 "value too big (%zu > %zu)",
+			 bkey_val_u64s(k.k), BKEY_BTREE_PTR_VAL_U64s_MAX);
+
+	ret = bch2_bkey_ptrs_invalid(c, k, flags, err);
+fsck_err:
+	return ret;
+}
+
+void bch2_btree_ptr_v2_to_text(struct printbuf *out, struct bch_fs *c,
+			       struct bkey_s_c k)
+{
+	struct bkey_s_c_btree_ptr_v2 bp = bkey_s_c_to_btree_ptr_v2(k);
+
+	prt_printf(out, "seq %llx written %u min_key %s",
+	       le64_to_cpu(bp.v->seq),
+	       le16_to_cpu(bp.v->sectors_written),
+	       BTREE_PTR_RANGE_UPDATED(bp.v) ? "R " : "");
+
+	bch2_bpos_to_text(out, bp.v->min_key);
+	prt_printf(out, " ");
+	bch2_bkey_ptrs_to_text(out, c, k);
+}
+
+void bch2_btree_ptr_v2_compat(enum btree_id btree_id, unsigned version,
+			      unsigned big_endian, int write,
+			      struct bkey_s k)
+{
+	struct bkey_s_btree_ptr_v2 bp = bkey_s_to_btree_ptr_v2(k);
+
+	compat_bpos(0, btree_id, version, big_endian, write, &bp.v->min_key);
+
+	if (version < bcachefs_metadata_version_inode_btree_change &&
+	    btree_id_is_extents(btree_id) &&
+	    !bkey_eq(bp.v->min_key, POS_MIN))
+		bp.v->min_key = write
+			? bpos_nosnap_predecessor(bp.v->min_key)
+			: bpos_nosnap_successor(bp.v->min_key);
+}
+
+/* KEY_TYPE_extent: */
+
+bool bch2_extent_merge(struct bch_fs *c, struct bkey_s l, struct bkey_s_c r)
+{
+	struct bkey_ptrs   l_ptrs = bch2_bkey_ptrs(l);
+	struct bkey_ptrs_c r_ptrs = bch2_bkey_ptrs_c(r);
+	union bch_extent_entry *en_l;
+	const union bch_extent_entry *en_r;
+	struct extent_ptr_decoded lp, rp;
+	bool use_right_ptr;
+	struct bch_dev *ca;
+
+	en_l = l_ptrs.start;
+	en_r = r_ptrs.start;
+	while (en_l < l_ptrs.end && en_r < r_ptrs.end) {
+		if (extent_entry_type(en_l) != extent_entry_type(en_r))
+			return false;
+
+		en_l = extent_entry_next(en_l);
+		en_r = extent_entry_next(en_r);
+	}
+
+	if (en_l < l_ptrs.end || en_r < r_ptrs.end)
+		return false;
+
+	en_l = l_ptrs.start;
+	en_r = r_ptrs.start;
+	lp.crc = bch2_extent_crc_unpack(l.k, NULL);
+	rp.crc = bch2_extent_crc_unpack(r.k, NULL);
+
+	while (__bkey_ptr_next_decode(l.k, l_ptrs.end, lp, en_l) &&
+	       __bkey_ptr_next_decode(r.k, r_ptrs.end, rp, en_r)) {
+		if (lp.ptr.offset + lp.crc.offset + lp.crc.live_size !=
+		    rp.ptr.offset + rp.crc.offset ||
+		    lp.ptr.dev			!= rp.ptr.dev ||
+		    lp.ptr.gen			!= rp.ptr.gen ||
+		    lp.ptr.unwritten		!= rp.ptr.unwritten ||
+		    lp.has_ec			!= rp.has_ec)
+			return false;
+
+		/* Extents may not straddle buckets: */
+		ca = bch_dev_bkey_exists(c, lp.ptr.dev);
+		if (PTR_BUCKET_NR(ca, &lp.ptr) != PTR_BUCKET_NR(ca, &rp.ptr))
+			return false;
+
+		if (lp.has_ec			!= rp.has_ec ||
+		    (lp.has_ec &&
+		     (lp.ec.block		!= rp.ec.block ||
+		      lp.ec.redundancy		!= rp.ec.redundancy ||
+		      lp.ec.idx			!= rp.ec.idx)))
+			return false;
+
+		if (lp.crc.compression_type	!= rp.crc.compression_type ||
+		    lp.crc.nonce		!= rp.crc.nonce)
+			return false;
+
+		if (lp.crc.offset + lp.crc.live_size + rp.crc.live_size <=
+		    lp.crc.uncompressed_size) {
+			/* can use left extent's crc entry */
+		} else if (lp.crc.live_size <= rp.crc.offset) {
+			/* can use right extent's crc entry */
+		} else {
+			/* check if checksums can be merged: */
+			if (lp.crc.csum_type		!= rp.crc.csum_type ||
+			    lp.crc.nonce		!= rp.crc.nonce ||
+			    crc_is_compressed(lp.crc) ||
+			    !bch2_checksum_mergeable(lp.crc.csum_type))
+				return false;
+
+			if (lp.crc.offset + lp.crc.live_size != lp.crc.compressed_size ||
+			    rp.crc.offset)
+				return false;
+
+			if (lp.crc.csum_type &&
+			    lp.crc.uncompressed_size +
+			    rp.crc.uncompressed_size > (c->opts.encoded_extent_max >> 9))
+				return false;
+		}
+
+		en_l = extent_entry_next(en_l);
+		en_r = extent_entry_next(en_r);
+	}
+
+	en_l = l_ptrs.start;
+	en_r = r_ptrs.start;
+	while (en_l < l_ptrs.end && en_r < r_ptrs.end) {
+		if (extent_entry_is_crc(en_l)) {
+			struct bch_extent_crc_unpacked crc_l = bch2_extent_crc_unpack(l.k, entry_to_crc(en_l));
+			struct bch_extent_crc_unpacked crc_r = bch2_extent_crc_unpack(r.k, entry_to_crc(en_r));
+
+			if (crc_l.uncompressed_size + crc_r.uncompressed_size >
+			    bch2_crc_field_size_max[extent_entry_type(en_l)])
+				return false;
+		}
+
+		en_l = extent_entry_next(en_l);
+		en_r = extent_entry_next(en_r);
+	}
+
+	use_right_ptr = false;
+	en_l = l_ptrs.start;
+	en_r = r_ptrs.start;
+	while (en_l < l_ptrs.end) {
+		if (extent_entry_type(en_l) == BCH_EXTENT_ENTRY_ptr &&
+		    use_right_ptr)
+			en_l->ptr = en_r->ptr;
+
+		if (extent_entry_is_crc(en_l)) {
+			struct bch_extent_crc_unpacked crc_l =
+				bch2_extent_crc_unpack(l.k, entry_to_crc(en_l));
+			struct bch_extent_crc_unpacked crc_r =
+				bch2_extent_crc_unpack(r.k, entry_to_crc(en_r));
+
+			use_right_ptr = false;
+
+			if (crc_l.offset + crc_l.live_size + crc_r.live_size <=
+			    crc_l.uncompressed_size) {
+				/* can use left extent's crc entry */
+			} else if (crc_l.live_size <= crc_r.offset) {
+				/* can use right extent's crc entry */
+				crc_r.offset -= crc_l.live_size;
+				bch2_extent_crc_pack(entry_to_crc(en_l), crc_r,
+						     extent_entry_type(en_l));
+				use_right_ptr = true;
+			} else {
+				crc_l.csum = bch2_checksum_merge(crc_l.csum_type,
+								 crc_l.csum,
+								 crc_r.csum,
+								 crc_r.uncompressed_size << 9);
+
+				crc_l.uncompressed_size	+= crc_r.uncompressed_size;
+				crc_l.compressed_size	+= crc_r.compressed_size;
+				bch2_extent_crc_pack(entry_to_crc(en_l), crc_l,
+						     extent_entry_type(en_l));
+			}
+		}
+
+		en_l = extent_entry_next(en_l);
+		en_r = extent_entry_next(en_r);
+	}
+
+	bch2_key_resize(l.k, l.k->size + r.k->size);
+	return true;
+}
+
+/* KEY_TYPE_reservation: */
+
+int bch2_reservation_invalid(struct bch_fs *c, struct bkey_s_c k,
+			     enum bkey_invalid_flags flags,
+			     struct printbuf *err)
+{
+	struct bkey_s_c_reservation r = bkey_s_c_to_reservation(k);
+	int ret = 0;
+
+	bkey_fsck_err_on(!r.v->nr_replicas || r.v->nr_replicas > BCH_REPLICAS_MAX, c, err,
+			 reservation_key_nr_replicas_invalid,
+			 "invalid nr_replicas (%u)", r.v->nr_replicas);
+fsck_err:
+	return ret;
+}
+
+void bch2_reservation_to_text(struct printbuf *out, struct bch_fs *c,
+			      struct bkey_s_c k)
+{
+	struct bkey_s_c_reservation r = bkey_s_c_to_reservation(k);
+
+	prt_printf(out, "generation %u replicas %u",
+	       le32_to_cpu(r.v->generation),
+	       r.v->nr_replicas);
+}
+
+bool bch2_reservation_merge(struct bch_fs *c, struct bkey_s _l, struct bkey_s_c _r)
+{
+	struct bkey_s_reservation l = bkey_s_to_reservation(_l);
+	struct bkey_s_c_reservation r = bkey_s_c_to_reservation(_r);
+
+	if (l.v->generation != r.v->generation ||
+	    l.v->nr_replicas != r.v->nr_replicas)
+		return false;
+
+	bch2_key_resize(l.k, l.k->size + r.k->size);
+	return true;
+}
+
+/* Extent checksum entries: */
+
+/* returns true if not equal */
+static inline bool bch2_crc_unpacked_cmp(struct bch_extent_crc_unpacked l,
+					 struct bch_extent_crc_unpacked r)
+{
+	return (l.csum_type		!= r.csum_type ||
+		l.compression_type	!= r.compression_type ||
+		l.compressed_size	!= r.compressed_size ||
+		l.uncompressed_size	!= r.uncompressed_size ||
+		l.offset		!= r.offset ||
+		l.live_size		!= r.live_size ||
+		l.nonce			!= r.nonce ||
+		bch2_crc_cmp(l.csum, r.csum));
+}
+
+static inline bool can_narrow_crc(struct bch_extent_crc_unpacked u,
+				  struct bch_extent_crc_unpacked n)
+{
+	return !crc_is_compressed(u) &&
+		u.csum_type &&
+		u.uncompressed_size > u.live_size &&
+		bch2_csum_type_is_encryption(u.csum_type) ==
+		bch2_csum_type_is_encryption(n.csum_type);
+}
+
+bool bch2_can_narrow_extent_crcs(struct bkey_s_c k,
+				 struct bch_extent_crc_unpacked n)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	struct bch_extent_crc_unpacked crc;
+	const union bch_extent_entry *i;
+
+	if (!n.csum_type)
+		return false;
+
+	bkey_for_each_crc(k.k, ptrs, crc, i)
+		if (can_narrow_crc(crc, n))
+			return true;
+
+	return false;
+}
+
+/*
+ * We're writing another replica for this extent, so while we've got the data in
+ * memory we'll be computing a new checksum for the currently live data.
+ *
+ * If there are other replicas we aren't moving, and they are checksummed but
+ * not compressed, we can modify them to point to only the data that is
+ * currently live (so that readers won't have to bounce) while we've got the
+ * checksum we need:
+ */
+bool bch2_bkey_narrow_crcs(struct bkey_i *k, struct bch_extent_crc_unpacked n)
+{
+	struct bkey_ptrs ptrs = bch2_bkey_ptrs(bkey_i_to_s(k));
+	struct bch_extent_crc_unpacked u;
+	struct extent_ptr_decoded p;
+	union bch_extent_entry *i;
+	bool ret = false;
+
+	/* Find a checksum entry that covers only live data: */
+	if (!n.csum_type) {
+		bkey_for_each_crc(&k->k, ptrs, u, i)
+			if (!crc_is_compressed(u) &&
+			    u.csum_type &&
+			    u.live_size == u.uncompressed_size) {
+				n = u;
+				goto found;
+			}
+		return false;
+	}
+found:
+	BUG_ON(crc_is_compressed(n));
+	BUG_ON(n.offset);
+	BUG_ON(n.live_size != k->k.size);
+
+restart_narrow_pointers:
+	ptrs = bch2_bkey_ptrs(bkey_i_to_s(k));
+
+	bkey_for_each_ptr_decode(&k->k, ptrs, p, i)
+		if (can_narrow_crc(p.crc, n)) {
+			bch2_bkey_drop_ptr_noerror(bkey_i_to_s(k), &i->ptr);
+			p.ptr.offset += p.crc.offset;
+			p.crc = n;
+			bch2_extent_ptr_decoded_append(k, &p);
+			ret = true;
+			goto restart_narrow_pointers;
+		}
+
+	return ret;
+}
+
+static void bch2_extent_crc_pack(union bch_extent_crc *dst,
+				 struct bch_extent_crc_unpacked src,
+				 enum bch_extent_entry_type type)
+{
+#define set_common_fields(_dst, _src)					\
+		_dst.type		= 1 << type;			\
+		_dst.csum_type		= _src.csum_type,		\
+		_dst.compression_type	= _src.compression_type,	\
+		_dst._compressed_size	= _src.compressed_size - 1,	\
+		_dst._uncompressed_size	= _src.uncompressed_size - 1,	\
+		_dst.offset		= _src.offset
+
+	switch (type) {
+	case BCH_EXTENT_ENTRY_crc32:
+		set_common_fields(dst->crc32, src);
+		dst->crc32.csum		= (u32 __force) *((__le32 *) &src.csum.lo);
+		break;
+	case BCH_EXTENT_ENTRY_crc64:
+		set_common_fields(dst->crc64, src);
+		dst->crc64.nonce	= src.nonce;
+		dst->crc64.csum_lo	= (u64 __force) src.csum.lo;
+		dst->crc64.csum_hi	= (u64 __force) *((__le16 *) &src.csum.hi);
+		break;
+	case BCH_EXTENT_ENTRY_crc128:
+		set_common_fields(dst->crc128, src);
+		dst->crc128.nonce	= src.nonce;
+		dst->crc128.csum	= src.csum;
+		break;
+	default:
+		BUG();
+	}
+#undef set_common_fields
+}
+
+void bch2_extent_crc_append(struct bkey_i *k,
+			    struct bch_extent_crc_unpacked new)
+{
+	struct bkey_ptrs ptrs = bch2_bkey_ptrs(bkey_i_to_s(k));
+	union bch_extent_crc *crc = (void *) ptrs.end;
+	enum bch_extent_entry_type type;
+
+	if (bch_crc_bytes[new.csum_type]	<= 4 &&
+	    new.uncompressed_size		<= CRC32_SIZE_MAX &&
+	    new.nonce				<= CRC32_NONCE_MAX)
+		type = BCH_EXTENT_ENTRY_crc32;
+	else if (bch_crc_bytes[new.csum_type]	<= 10 &&
+		   new.uncompressed_size	<= CRC64_SIZE_MAX &&
+		   new.nonce			<= CRC64_NONCE_MAX)
+		type = BCH_EXTENT_ENTRY_crc64;
+	else if (bch_crc_bytes[new.csum_type]	<= 16 &&
+		   new.uncompressed_size	<= CRC128_SIZE_MAX &&
+		   new.nonce			<= CRC128_NONCE_MAX)
+		type = BCH_EXTENT_ENTRY_crc128;
+	else
+		BUG();
+
+	bch2_extent_crc_pack(crc, new, type);
+
+	k->k.u64s += extent_entry_u64s(ptrs.end);
+
+	EBUG_ON(bkey_val_u64s(&k->k) > BKEY_EXTENT_VAL_U64s_MAX);
+}
+
+/* Generic code for keys with pointers: */
+
+unsigned bch2_bkey_nr_ptrs(struct bkey_s_c k)
+{
+	return bch2_bkey_devs(k).nr;
+}
+
+unsigned bch2_bkey_nr_ptrs_allocated(struct bkey_s_c k)
+{
+	return k.k->type == KEY_TYPE_reservation
+		? bkey_s_c_to_reservation(k).v->nr_replicas
+		: bch2_bkey_dirty_devs(k).nr;
+}
+
+unsigned bch2_bkey_nr_ptrs_fully_allocated(struct bkey_s_c k)
+{
+	unsigned ret = 0;
+
+	if (k.k->type == KEY_TYPE_reservation) {
+		ret = bkey_s_c_to_reservation(k).v->nr_replicas;
+	} else {
+		struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+		const union bch_extent_entry *entry;
+		struct extent_ptr_decoded p;
+
+		bkey_for_each_ptr_decode(k.k, ptrs, p, entry)
+			ret += !p.ptr.cached && !crc_is_compressed(p.crc);
+	}
+
+	return ret;
+}
+
+unsigned bch2_bkey_sectors_compressed(struct bkey_s_c k)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+	struct extent_ptr_decoded p;
+	unsigned ret = 0;
+
+	bkey_for_each_ptr_decode(k.k, ptrs, p, entry)
+		if (!p.ptr.cached && crc_is_compressed(p.crc))
+			ret += p.crc.compressed_size;
+
+	return ret;
+}
+
+bool bch2_bkey_is_incompressible(struct bkey_s_c k)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+	struct bch_extent_crc_unpacked crc;
+
+	bkey_for_each_crc(k.k, ptrs, crc, entry)
+		if (crc.compression_type == BCH_COMPRESSION_TYPE_incompressible)
+			return true;
+	return false;
+}
+
+unsigned bch2_bkey_replicas(struct bch_fs *c, struct bkey_s_c k)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+	struct extent_ptr_decoded p = { 0 };
+	unsigned replicas = 0;
+
+	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
+		if (p.ptr.cached)
+			continue;
+
+		if (p.has_ec)
+			replicas += p.ec.redundancy;
+
+		replicas++;
+
+	}
+
+	return replicas;
+}
+
+static inline unsigned __extent_ptr_durability(struct bch_dev *ca, struct extent_ptr_decoded *p)
+{
+	if (p->ptr.cached)
+		return 0;
+
+	return p->has_ec
+		? p->ec.redundancy + 1
+		: ca->mi.durability;
+}
+
+unsigned bch2_extent_ptr_desired_durability(struct bch_fs *c, struct extent_ptr_decoded *p)
+{
+	struct bch_dev *ca = bch_dev_bkey_exists(c, p->ptr.dev);
+
+	return __extent_ptr_durability(ca, p);
+}
+
+unsigned bch2_extent_ptr_durability(struct bch_fs *c, struct extent_ptr_decoded *p)
+{
+	struct bch_dev *ca = bch_dev_bkey_exists(c, p->ptr.dev);
+
+	if (ca->mi.state == BCH_MEMBER_STATE_failed)
+		return 0;
+
+	return __extent_ptr_durability(ca, p);
+}
+
+unsigned bch2_bkey_durability(struct bch_fs *c, struct bkey_s_c k)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+	struct extent_ptr_decoded p;
+	unsigned durability = 0;
+
+	bkey_for_each_ptr_decode(k.k, ptrs, p, entry)
+		durability += bch2_extent_ptr_durability(c, &p);
+
+	return durability;
+}
+
+static unsigned bch2_bkey_durability_safe(struct bch_fs *c, struct bkey_s_c k)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+	struct extent_ptr_decoded p;
+	unsigned durability = 0;
+
+	bkey_for_each_ptr_decode(k.k, ptrs, p, entry)
+		if (p.ptr.dev < c->sb.nr_devices && c->devs[p.ptr.dev])
+			durability += bch2_extent_ptr_durability(c, &p);
+
+	return durability;
+}
+
+void bch2_bkey_extent_entry_drop(struct bkey_i *k, union bch_extent_entry *entry)
+{
+	union bch_extent_entry *end = bkey_val_end(bkey_i_to_s(k));
+	union bch_extent_entry *next = extent_entry_next(entry);
+
+	memmove_u64s(entry, next, (u64 *) end - (u64 *) next);
+	k->k.u64s -= extent_entry_u64s(entry);
+}
+
+void bch2_extent_ptr_decoded_append(struct bkey_i *k,
+				    struct extent_ptr_decoded *p)
+{
+	struct bkey_ptrs ptrs = bch2_bkey_ptrs(bkey_i_to_s(k));
+	struct bch_extent_crc_unpacked crc =
+		bch2_extent_crc_unpack(&k->k, NULL);
+	union bch_extent_entry *pos;
+
+	if (!bch2_crc_unpacked_cmp(crc, p->crc)) {
+		pos = ptrs.start;
+		goto found;
+	}
+
+	bkey_for_each_crc(&k->k, ptrs, crc, pos)
+		if (!bch2_crc_unpacked_cmp(crc, p->crc)) {
+			pos = extent_entry_next(pos);
+			goto found;
+		}
+
+	bch2_extent_crc_append(k, p->crc);
+	pos = bkey_val_end(bkey_i_to_s(k));
+found:
+	p->ptr.type = 1 << BCH_EXTENT_ENTRY_ptr;
+	__extent_entry_insert(k, pos, to_entry(&p->ptr));
+
+	if (p->has_ec) {
+		p->ec.type = 1 << BCH_EXTENT_ENTRY_stripe_ptr;
+		__extent_entry_insert(k, pos, to_entry(&p->ec));
+	}
+}
+
+static union bch_extent_entry *extent_entry_prev(struct bkey_ptrs ptrs,
+					  union bch_extent_entry *entry)
+{
+	union bch_extent_entry *i = ptrs.start;
+
+	if (i == entry)
+		return NULL;
+
+	while (extent_entry_next(i) != entry)
+		i = extent_entry_next(i);
+	return i;
+}
+
+/*
+ * Returns pointer to the next entry after the one being dropped:
+ */
+union bch_extent_entry *bch2_bkey_drop_ptr_noerror(struct bkey_s k,
+						   struct bch_extent_ptr *ptr)
+{
+	struct bkey_ptrs ptrs = bch2_bkey_ptrs(k);
+	union bch_extent_entry *entry = to_entry(ptr), *next;
+	union bch_extent_entry *ret = entry;
+	bool drop_crc = true;
+
+	EBUG_ON(ptr < &ptrs.start->ptr ||
+		ptr >= &ptrs.end->ptr);
+	EBUG_ON(ptr->type != 1 << BCH_EXTENT_ENTRY_ptr);
+
+	for (next = extent_entry_next(entry);
+	     next != ptrs.end;
+	     next = extent_entry_next(next)) {
+		if (extent_entry_is_crc(next)) {
+			break;
+		} else if (extent_entry_is_ptr(next)) {
+			drop_crc = false;
+			break;
+		}
+	}
+
+	extent_entry_drop(k, entry);
+
+	while ((entry = extent_entry_prev(ptrs, entry))) {
+		if (extent_entry_is_ptr(entry))
+			break;
+
+		if ((extent_entry_is_crc(entry) && drop_crc) ||
+		    extent_entry_is_stripe_ptr(entry)) {
+			ret = (void *) ret - extent_entry_bytes(entry);
+			extent_entry_drop(k, entry);
+		}
+	}
+
+	return ret;
+}
+
+union bch_extent_entry *bch2_bkey_drop_ptr(struct bkey_s k,
+					   struct bch_extent_ptr *ptr)
+{
+	bool have_dirty = bch2_bkey_dirty_devs(k.s_c).nr;
+	union bch_extent_entry *ret =
+		bch2_bkey_drop_ptr_noerror(k, ptr);
+
+	/*
+	 * If we deleted all the dirty pointers and there's still cached
+	 * pointers, we could set the cached pointers to dirty if they're not
+	 * stale - but to do that correctly we'd need to grab an open_bucket
+	 * reference so that we don't race with bucket reuse:
+	 */
+	if (have_dirty &&
+	    !bch2_bkey_dirty_devs(k.s_c).nr) {
+		k.k->type = KEY_TYPE_error;
+		set_bkey_val_u64s(k.k, 0);
+		ret = NULL;
+	} else if (!bch2_bkey_nr_ptrs(k.s_c)) {
+		k.k->type = KEY_TYPE_deleted;
+		set_bkey_val_u64s(k.k, 0);
+		ret = NULL;
+	}
+
+	return ret;
+}
+
+void bch2_bkey_drop_device(struct bkey_s k, unsigned dev)
+{
+	struct bch_extent_ptr *ptr;
+
+	bch2_bkey_drop_ptrs(k, ptr, ptr->dev == dev);
+}
+
+void bch2_bkey_drop_device_noerror(struct bkey_s k, unsigned dev)
+{
+	struct bch_extent_ptr *ptr = bch2_bkey_has_device(k, dev);
+
+	if (ptr)
+		bch2_bkey_drop_ptr_noerror(k, ptr);
+}
+
+const struct bch_extent_ptr *bch2_bkey_has_device_c(struct bkey_s_c k, unsigned dev)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const struct bch_extent_ptr *ptr;
+
+	bkey_for_each_ptr(ptrs, ptr)
+		if (ptr->dev == dev)
+			return ptr;
+
+	return NULL;
+}
+
+bool bch2_bkey_has_target(struct bch_fs *c, struct bkey_s_c k, unsigned target)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const struct bch_extent_ptr *ptr;
+
+	bkey_for_each_ptr(ptrs, ptr)
+		if (bch2_dev_in_target(c, ptr->dev, target) &&
+		    (!ptr->cached ||
+		     !ptr_stale(bch_dev_bkey_exists(c, ptr->dev), ptr)))
+			return true;
+
+	return false;
+}
+
+bool bch2_bkey_matches_ptr(struct bch_fs *c, struct bkey_s_c k,
+			   struct bch_extent_ptr m, u64 offset)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+	struct extent_ptr_decoded p;
+
+	bkey_for_each_ptr_decode(k.k, ptrs, p, entry)
+		if (p.ptr.dev	== m.dev &&
+		    p.ptr.gen	== m.gen &&
+		    (s64) p.ptr.offset + p.crc.offset - bkey_start_offset(k.k) ==
+		    (s64) m.offset  - offset)
+			return true;
+
+	return false;
+}
+
+/*
+ * Returns true if two extents refer to the same data:
+ */
+bool bch2_extents_match(struct bkey_s_c k1, struct bkey_s_c k2)
+{
+	if (k1.k->type != k2.k->type)
+		return false;
+
+	if (bkey_extent_is_direct_data(k1.k)) {
+		struct bkey_ptrs_c ptrs1 = bch2_bkey_ptrs_c(k1);
+		struct bkey_ptrs_c ptrs2 = bch2_bkey_ptrs_c(k2);
+		const union bch_extent_entry *entry1, *entry2;
+		struct extent_ptr_decoded p1, p2;
+
+		if (bkey_extent_is_unwritten(k1) != bkey_extent_is_unwritten(k2))
+			return false;
+
+		bkey_for_each_ptr_decode(k1.k, ptrs1, p1, entry1)
+			bkey_for_each_ptr_decode(k2.k, ptrs2, p2, entry2)
+				if (p1.ptr.dev		== p2.ptr.dev &&
+				    p1.ptr.gen		== p2.ptr.gen &&
+				    (s64) p1.ptr.offset + p1.crc.offset - bkey_start_offset(k1.k) ==
+				    (s64) p2.ptr.offset + p2.crc.offset - bkey_start_offset(k2.k))
+					return true;
+
+		return false;
+	} else {
+		/* KEY_TYPE_deleted, etc. */
+		return true;
+	}
+}
+
+struct bch_extent_ptr *
+bch2_extent_has_ptr(struct bkey_s_c k1, struct extent_ptr_decoded p1, struct bkey_s k2)
+{
+	struct bkey_ptrs ptrs2 = bch2_bkey_ptrs(k2);
+	union bch_extent_entry *entry2;
+	struct extent_ptr_decoded p2;
+
+	bkey_for_each_ptr_decode(k2.k, ptrs2, p2, entry2)
+		if (p1.ptr.dev		== p2.ptr.dev &&
+		    p1.ptr.gen		== p2.ptr.gen &&
+		    (s64) p1.ptr.offset + p1.crc.offset - bkey_start_offset(k1.k) ==
+		    (s64) p2.ptr.offset + p2.crc.offset - bkey_start_offset(k2.k))
+			return &entry2->ptr;
+
+	return NULL;
+}
+
+void bch2_extent_ptr_set_cached(struct bkey_s k, struct bch_extent_ptr *ptr)
+{
+	struct bkey_ptrs ptrs = bch2_bkey_ptrs(k);
+	union bch_extent_entry *entry;
+	union bch_extent_entry *ec = NULL;
+
+	bkey_extent_entry_for_each(ptrs, entry) {
+		if (&entry->ptr == ptr) {
+			ptr->cached = true;
+			if (ec)
+				extent_entry_drop(k, ec);
+			return;
+		}
+
+		if (extent_entry_is_stripe_ptr(entry))
+			ec = entry;
+		else if (extent_entry_is_ptr(entry))
+			ec = NULL;
+	}
+
+	BUG();
+}
+
+/*
+ * bch_extent_normalize - clean up an extent, dropping stale pointers etc.
+ *
+ * Returns true if @k should be dropped entirely
+ *
+ * For existing keys, only called when btree nodes are being rewritten, not when
+ * they're merely being compacted/resorted in memory.
+ */
+bool bch2_extent_normalize(struct bch_fs *c, struct bkey_s k)
+{
+	struct bch_extent_ptr *ptr;
+
+	bch2_bkey_drop_ptrs(k, ptr,
+		ptr->cached &&
+		ptr_stale(bch_dev_bkey_exists(c, ptr->dev), ptr));
+
+	return bkey_deleted(k.k);
+}
+
+void bch2_bkey_ptrs_to_text(struct printbuf *out, struct bch_fs *c,
+			    struct bkey_s_c k)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+	bool first = true;
+
+	if (c)
+		prt_printf(out, "durability: %u ", bch2_bkey_durability_safe(c, k));
+
+	bkey_extent_entry_for_each(ptrs, entry) {
+		if (!first)
+			prt_printf(out, " ");
+
+		switch (__extent_entry_type(entry)) {
+		case BCH_EXTENT_ENTRY_ptr: {
+			const struct bch_extent_ptr *ptr = entry_to_ptr(entry);
+			struct bch_dev *ca = c && ptr->dev < c->sb.nr_devices && c->devs[ptr->dev]
+				? bch_dev_bkey_exists(c, ptr->dev)
+				: NULL;
+
+			if (!ca) {
+				prt_printf(out, "ptr: %u:%llu gen %u%s", ptr->dev,
+				       (u64) ptr->offset, ptr->gen,
+				       ptr->cached ? " cached" : "");
+			} else {
+				u32 offset;
+				u64 b = sector_to_bucket_and_offset(ca, ptr->offset, &offset);
+
+				prt_printf(out, "ptr: %u:%llu:%u gen %u",
+					   ptr->dev, b, offset, ptr->gen);
+				if (ptr->cached)
+					prt_str(out, " cached");
+				if (ptr->unwritten)
+					prt_str(out, " unwritten");
+				if (ca && ptr_stale(ca, ptr))
+					prt_printf(out, " stale");
+			}
+			break;
+		}
+		case BCH_EXTENT_ENTRY_crc32:
+		case BCH_EXTENT_ENTRY_crc64:
+		case BCH_EXTENT_ENTRY_crc128: {
+			struct bch_extent_crc_unpacked crc =
+				bch2_extent_crc_unpack(k.k, entry_to_crc(entry));
+
+			prt_printf(out, "crc: c_size %u size %u offset %u nonce %u csum %s compress %s",
+			       crc.compressed_size,
+			       crc.uncompressed_size,
+			       crc.offset, crc.nonce,
+			       bch2_csum_types[crc.csum_type],
+			       bch2_compression_types[crc.compression_type]);
+			break;
+		}
+		case BCH_EXTENT_ENTRY_stripe_ptr: {
+			const struct bch_extent_stripe_ptr *ec = &entry->stripe_ptr;
+
+			prt_printf(out, "ec: idx %llu block %u",
+			       (u64) ec->idx, ec->block);
+			break;
+		}
+		case BCH_EXTENT_ENTRY_rebalance: {
+			const struct bch_extent_rebalance *r = &entry->rebalance;
+
+			prt_str(out, "rebalance: target ");
+			if (c)
+				bch2_target_to_text(out, c, r->target);
+			else
+				prt_printf(out, "%u", r->target);
+			prt_str(out, " compression ");
+			bch2_compression_opt_to_text(out, r->compression);
+			break;
+		}
+		default:
+			prt_printf(out, "(invalid extent entry %.16llx)", *((u64 *) entry));
+			return;
+		}
+
+		first = false;
+	}
+}
+
+static int extent_ptr_invalid(struct bch_fs *c,
+			      struct bkey_s_c k,
+			      enum bkey_invalid_flags flags,
+			      const struct bch_extent_ptr *ptr,
+			      unsigned size_ondisk,
+			      bool metadata,
+			      struct printbuf *err)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const struct bch_extent_ptr *ptr2;
+	u64 bucket;
+	u32 bucket_offset;
+	struct bch_dev *ca;
+	int ret = 0;
+
+	if (!bch2_dev_exists2(c, ptr->dev)) {
+		/*
+		 * If we're in the write path this key might have already been
+		 * overwritten, and we could be seeing a device that doesn't
+		 * exist anymore due to racing with device removal:
+		 */
+		if (flags & BKEY_INVALID_WRITE)
+			return 0;
+
+		bkey_fsck_err(c, err, ptr_to_invalid_device,
+			   "pointer to invalid device (%u)", ptr->dev);
+	}
+
+	ca = bch_dev_bkey_exists(c, ptr->dev);
+	bkey_for_each_ptr(ptrs, ptr2)
+		bkey_fsck_err_on(ptr != ptr2 && ptr->dev == ptr2->dev, c, err,
+				 ptr_to_duplicate_device,
+				 "multiple pointers to same device (%u)", ptr->dev);
+
+	bucket = sector_to_bucket_and_offset(ca, ptr->offset, &bucket_offset);
+
+	bkey_fsck_err_on(bucket >= ca->mi.nbuckets, c, err,
+			 ptr_after_last_bucket,
+			 "pointer past last bucket (%llu > %llu)", bucket, ca->mi.nbuckets);
+	bkey_fsck_err_on(ptr->offset < bucket_to_sector(ca, ca->mi.first_bucket), c, err,
+			 ptr_before_first_bucket,
+			 "pointer before first bucket (%llu < %u)", bucket, ca->mi.first_bucket);
+	bkey_fsck_err_on(bucket_offset + size_ondisk > ca->mi.bucket_size, c, err,
+			 ptr_spans_multiple_buckets,
+			 "pointer spans multiple buckets (%u + %u > %u)",
+		       bucket_offset, size_ondisk, ca->mi.bucket_size);
+fsck_err:
+	return ret;
+}
+
+int bch2_bkey_ptrs_invalid(struct bch_fs *c, struct bkey_s_c k,
+			   enum bkey_invalid_flags flags,
+			   struct printbuf *err)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+	struct bch_extent_crc_unpacked crc;
+	unsigned size_ondisk = k.k->size;
+	unsigned nonce = UINT_MAX;
+	unsigned nr_ptrs = 0;
+	bool have_written = false, have_unwritten = false, have_ec = false, crc_since_last_ptr = false;
+	int ret = 0;
+
+	if (bkey_is_btree_ptr(k.k))
+		size_ondisk = btree_sectors(c);
+
+	bkey_extent_entry_for_each(ptrs, entry) {
+		bkey_fsck_err_on(__extent_entry_type(entry) >= BCH_EXTENT_ENTRY_MAX, c, err,
+			extent_ptrs_invalid_entry,
+			"invalid extent entry type (got %u, max %u)",
+			__extent_entry_type(entry), BCH_EXTENT_ENTRY_MAX);
+
+		bkey_fsck_err_on(bkey_is_btree_ptr(k.k) &&
+				 !extent_entry_is_ptr(entry), c, err,
+				 btree_ptr_has_non_ptr,
+				 "has non ptr field");
+
+		switch (extent_entry_type(entry)) {
+		case BCH_EXTENT_ENTRY_ptr:
+			ret = extent_ptr_invalid(c, k, flags, &entry->ptr,
+						 size_ondisk, false, err);
+			if (ret)
+				return ret;
+
+			bkey_fsck_err_on(entry->ptr.cached && have_ec, c, err,
+					 ptr_cached_and_erasure_coded,
+					 "cached, erasure coded ptr");
+
+			if (!entry->ptr.unwritten)
+				have_written = true;
+			else
+				have_unwritten = true;
+
+			have_ec = false;
+			crc_since_last_ptr = false;
+			nr_ptrs++;
+			break;
+		case BCH_EXTENT_ENTRY_crc32:
+		case BCH_EXTENT_ENTRY_crc64:
+		case BCH_EXTENT_ENTRY_crc128:
+			crc = bch2_extent_crc_unpack(k.k, entry_to_crc(entry));
+
+			bkey_fsck_err_on(crc.offset + crc.live_size > crc.uncompressed_size, c, err,
+					 ptr_crc_uncompressed_size_too_small,
+					 "checksum offset + key size > uncompressed size");
+			bkey_fsck_err_on(!bch2_checksum_type_valid(c, crc.csum_type), c, err,
+					 ptr_crc_csum_type_unknown,
+					 "invalid checksum type");
+			bkey_fsck_err_on(crc.compression_type >= BCH_COMPRESSION_TYPE_NR, c, err,
+					 ptr_crc_compression_type_unknown,
+					 "invalid compression type");
+
+			if (bch2_csum_type_is_encryption(crc.csum_type)) {
+				if (nonce == UINT_MAX)
+					nonce = crc.offset + crc.nonce;
+				else if (nonce != crc.offset + crc.nonce)
+					bkey_fsck_err(c, err, ptr_crc_nonce_mismatch,
+						      "incorrect nonce");
+			}
+
+			bkey_fsck_err_on(crc_since_last_ptr, c, err,
+					 ptr_crc_redundant,
+					 "redundant crc entry");
+			crc_since_last_ptr = true;
+
+			bkey_fsck_err_on(crc_is_encoded(crc) &&
+					 (crc.uncompressed_size > c->opts.encoded_extent_max >> 9) &&
+					 (flags & (BKEY_INVALID_WRITE|BKEY_INVALID_COMMIT)), c, err,
+					 ptr_crc_uncompressed_size_too_big,
+					 "too large encoded extent");
+
+			size_ondisk = crc.compressed_size;
+			break;
+		case BCH_EXTENT_ENTRY_stripe_ptr:
+			bkey_fsck_err_on(have_ec, c, err,
+					 ptr_stripe_redundant,
+					 "redundant stripe entry");
+			have_ec = true;
+			break;
+		case BCH_EXTENT_ENTRY_rebalance: {
+			const struct bch_extent_rebalance *r = &entry->rebalance;
+
+			if (!bch2_compression_opt_valid(r->compression)) {
+				struct bch_compression_opt opt = __bch2_compression_decode(r->compression);
+				prt_printf(err, "invalid compression opt %u:%u",
+					   opt.type, opt.level);
+				return -BCH_ERR_invalid_bkey;
+			}
+			break;
+		}
+		}
+	}
+
+	bkey_fsck_err_on(!nr_ptrs, c, err,
+			 extent_ptrs_no_ptrs,
+			 "no ptrs");
+	bkey_fsck_err_on(nr_ptrs > BCH_BKEY_PTRS_MAX, c, err,
+			 extent_ptrs_too_many_ptrs,
+			 "too many ptrs: %u > %u", nr_ptrs, BCH_BKEY_PTRS_MAX);
+	bkey_fsck_err_on(have_written && have_unwritten, c, err,
+			 extent_ptrs_written_and_unwritten,
+			 "extent with unwritten and written ptrs");
+	bkey_fsck_err_on(k.k->type != KEY_TYPE_extent && have_unwritten, c, err,
+			 extent_ptrs_unwritten,
+			 "has unwritten ptrs");
+	bkey_fsck_err_on(crc_since_last_ptr, c, err,
+			 extent_ptrs_redundant_crc,
+			 "redundant crc entry");
+	bkey_fsck_err_on(have_ec, c, err,
+			 extent_ptrs_redundant_stripe,
+			 "redundant stripe entry");
+fsck_err:
+	return ret;
+}
+
+void bch2_ptr_swab(struct bkey_s k)
+{
+	struct bkey_ptrs ptrs = bch2_bkey_ptrs(k);
+	union bch_extent_entry *entry;
+	u64 *d;
+
+	for (d =  (u64 *) ptrs.start;
+	     d != (u64 *) ptrs.end;
+	     d++)
+		*d = swab64(*d);
+
+	for (entry = ptrs.start;
+	     entry < ptrs.end;
+	     entry = extent_entry_next(entry)) {
+		switch (extent_entry_type(entry)) {
+		case BCH_EXTENT_ENTRY_ptr:
+			break;
+		case BCH_EXTENT_ENTRY_crc32:
+			entry->crc32.csum = swab32(entry->crc32.csum);
+			break;
+		case BCH_EXTENT_ENTRY_crc64:
+			entry->crc64.csum_hi = swab16(entry->crc64.csum_hi);
+			entry->crc64.csum_lo = swab64(entry->crc64.csum_lo);
+			break;
+		case BCH_EXTENT_ENTRY_crc128:
+			entry->crc128.csum.hi = (__force __le64)
+				swab64((__force u64) entry->crc128.csum.hi);
+			entry->crc128.csum.lo = (__force __le64)
+				swab64((__force u64) entry->crc128.csum.lo);
+			break;
+		case BCH_EXTENT_ENTRY_stripe_ptr:
+			break;
+		case BCH_EXTENT_ENTRY_rebalance:
+			break;
+		}
+	}
+}
+
+const struct bch_extent_rebalance *bch2_bkey_rebalance_opts(struct bkey_s_c k)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	const union bch_extent_entry *entry;
+
+	bkey_extent_entry_for_each(ptrs, entry)
+		if (__extent_entry_type(entry) == BCH_EXTENT_ENTRY_rebalance)
+			return &entry->rebalance;
+
+	return NULL;
+}
+
+unsigned bch2_bkey_ptrs_need_rebalance(struct bch_fs *c, struct bkey_s_c k,
+				       unsigned target, unsigned compression)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	unsigned rewrite_ptrs = 0;
+
+	if (compression) {
+		unsigned compression_type = bch2_compression_opt_to_type(compression);
+		const union bch_extent_entry *entry;
+		struct extent_ptr_decoded p;
+		unsigned i = 0;
+
+		bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
+			if (p.crc.compression_type == BCH_COMPRESSION_TYPE_incompressible ||
+			    p.ptr.unwritten) {
+				rewrite_ptrs = 0;
+				goto incompressible;
+			}
+
+			if (!p.ptr.cached && p.crc.compression_type != compression_type)
+				rewrite_ptrs |= 1U << i;
+			i++;
+		}
+	}
+incompressible:
+	if (target && bch2_target_accepts_data(c, BCH_DATA_user, target)) {
+		const struct bch_extent_ptr *ptr;
+		unsigned i = 0;
+
+		bkey_for_each_ptr(ptrs, ptr) {
+			if (!ptr->cached && !bch2_dev_in_target(c, ptr->dev, target))
+				rewrite_ptrs |= 1U << i;
+			i++;
+		}
+	}
+
+	return rewrite_ptrs;
+}
+
+bool bch2_bkey_needs_rebalance(struct bch_fs *c, struct bkey_s_c k)
+{
+	const struct bch_extent_rebalance *r = bch2_bkey_rebalance_opts(k);
+
+	/*
+	 * If it's an indirect extent, we don't delete the rebalance entry when
+	 * done so that we know what options were applied - check if it still
+	 * needs work done:
+	 */
+	if (r &&
+	    k.k->type == KEY_TYPE_reflink_v &&
+	    !bch2_bkey_ptrs_need_rebalance(c, k, r->target, r->compression))
+		r = NULL;
+
+	return r != NULL;
+}
+
+int bch2_bkey_set_needs_rebalance(struct bch_fs *c, struct bkey_i *_k,
+				  unsigned target, unsigned compression)
+{
+	struct bkey_s k = bkey_i_to_s(_k);
+	struct bch_extent_rebalance *r;
+	bool needs_rebalance;
+
+	if (!bkey_extent_is_direct_data(k.k))
+		return 0;
+
+	/* get existing rebalance entry: */
+	r = (struct bch_extent_rebalance *) bch2_bkey_rebalance_opts(k.s_c);
+	if (r) {
+		if (k.k->type == KEY_TYPE_reflink_v) {
+			/*
+			 * indirect extents: existing options take precedence,
+			 * so that we don't move extents back and forth if
+			 * they're referenced by different inodes with different
+			 * options:
+			 */
+			if (r->target)
+				target = r->target;
+			if (r->compression)
+				compression = r->compression;
+		}
+
+		r->target	= target;
+		r->compression	= compression;
+	}
+
+	needs_rebalance = bch2_bkey_ptrs_need_rebalance(c, k.s_c, target, compression);
+
+	if (needs_rebalance && !r) {
+		union bch_extent_entry *new = bkey_val_end(k);
+
+		new->rebalance.type		= 1U << BCH_EXTENT_ENTRY_rebalance;
+		new->rebalance.compression	= compression;
+		new->rebalance.target		= target;
+		new->rebalance.unused		= 0;
+		k.k->u64s += extent_entry_u64s(new);
+	} else if (!needs_rebalance && r && k.k->type != KEY_TYPE_reflink_v) {
+		/*
+		 * For indirect extents, don't delete the rebalance entry when
+		 * we're finished so that we know we specifically moved it or
+		 * compressed it to its current location/compression type
+		 */
+		extent_entry_drop(k, (union bch_extent_entry *) r);
+	}
+
+	return 0;
+}
+
+/* Generic extent code: */
+
+int bch2_cut_front_s(struct bpos where, struct bkey_s k)
+{
+	unsigned new_val_u64s = bkey_val_u64s(k.k);
+	int val_u64s_delta;
+	u64 sub;
+
+	if (bkey_le(where, bkey_start_pos(k.k)))
+		return 0;
+
+	EBUG_ON(bkey_gt(where, k.k->p));
+
+	sub = where.offset - bkey_start_offset(k.k);
+
+	k.k->size -= sub;
+
+	if (!k.k->size) {
+		k.k->type = KEY_TYPE_deleted;
+		new_val_u64s = 0;
+	}
+
+	switch (k.k->type) {
+	case KEY_TYPE_extent:
+	case KEY_TYPE_reflink_v: {
+		struct bkey_ptrs ptrs = bch2_bkey_ptrs(k);
+		union bch_extent_entry *entry;
+		bool seen_crc = false;
+
+		bkey_extent_entry_for_each(ptrs, entry) {
+			switch (extent_entry_type(entry)) {
+			case BCH_EXTENT_ENTRY_ptr:
+				if (!seen_crc)
+					entry->ptr.offset += sub;
+				break;
+			case BCH_EXTENT_ENTRY_crc32:
+				entry->crc32.offset += sub;
+				break;
+			case BCH_EXTENT_ENTRY_crc64:
+				entry->crc64.offset += sub;
+				break;
+			case BCH_EXTENT_ENTRY_crc128:
+				entry->crc128.offset += sub;
+				break;
+			case BCH_EXTENT_ENTRY_stripe_ptr:
+				break;
+			case BCH_EXTENT_ENTRY_rebalance:
+				break;
+			}
+
+			if (extent_entry_is_crc(entry))
+				seen_crc = true;
+		}
+
+		break;
+	}
+	case KEY_TYPE_reflink_p: {
+		struct bkey_s_reflink_p p = bkey_s_to_reflink_p(k);
+
+		le64_add_cpu(&p.v->idx, sub);
+		break;
+	}
+	case KEY_TYPE_inline_data:
+	case KEY_TYPE_indirect_inline_data: {
+		void *p = bkey_inline_data_p(k);
+		unsigned bytes = bkey_inline_data_bytes(k.k);
+
+		sub = min_t(u64, sub << 9, bytes);
+
+		memmove(p, p + sub, bytes - sub);
+
+		new_val_u64s -= sub >> 3;
+		break;
+	}
+	}
+
+	val_u64s_delta = bkey_val_u64s(k.k) - new_val_u64s;
+	BUG_ON(val_u64s_delta < 0);
+
+	set_bkey_val_u64s(k.k, new_val_u64s);
+	memset(bkey_val_end(k), 0, val_u64s_delta * sizeof(u64));
+	return -val_u64s_delta;
+}
+
+int bch2_cut_back_s(struct bpos where, struct bkey_s k)
+{
+	unsigned new_val_u64s = bkey_val_u64s(k.k);
+	int val_u64s_delta;
+	u64 len = 0;
+
+	if (bkey_ge(where, k.k->p))
+		return 0;
+
+	EBUG_ON(bkey_lt(where, bkey_start_pos(k.k)));
+
+	len = where.offset - bkey_start_offset(k.k);
+
+	k.k->p.offset = where.offset;
+	k.k->size = len;
+
+	if (!len) {
+		k.k->type = KEY_TYPE_deleted;
+		new_val_u64s = 0;
+	}
+
+	switch (k.k->type) {
+	case KEY_TYPE_inline_data:
+	case KEY_TYPE_indirect_inline_data:
+		new_val_u64s = (bkey_inline_data_offset(k.k) +
+				min(bkey_inline_data_bytes(k.k), k.k->size << 9)) >> 3;
+		break;
+	}
+
+	val_u64s_delta = bkey_val_u64s(k.k) - new_val_u64s;
+	BUG_ON(val_u64s_delta < 0);
+
+	set_bkey_val_u64s(k.k, new_val_u64s);
+	memset(bkey_val_end(k), 0, val_u64s_delta * sizeof(u64));
+	return -val_u64s_delta;
+}