bcachefs: Redo data_update interface

This patch significantly cleans up and simplifies the data_update
interface. Instead of only being able to specify a single pointer by
device to rewrite, we're now able to specify any or all of the pointers
in the original extent to be rewrited, as a bitmask.

data_cmd is no more: the various pred functions now just return true if
the extent should be moved/updated. All the data_update path does is
rewrite existing replicas, or add new ones.

This fixes a bug where with background compression on replicated
filesystems, where rebalance -> data_update would incorrectly drop the
wrong old replica, and keep trying to recompress an extent pointer and
each time failing to drop the right replica. Oops.

Now, the data update path doesn't look at the io options to decide which
pointers to keep and which to drop - it only goes off of the
data_update_options passed to it.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

1 files changed, 50 insertions, 33 deletions

diff --git a/fs/bcachefs/extents.c b/fs/bcachefs/extents.c
index 4e44234a2b2c..38836c1990aa 100644
--- a/fs/bcachefs/extents.c
+++ b/fs/bcachefs/extents.c
@@ -25,6 +25,8 @@
 #include "trace.h"
 #include "util.h"
 
+static union bch_extent_entry *__bch2_bkey_drop_ptr(struct bkey_s, struct bch_extent_ptr *);
+
 static unsigned bch2_crc_field_size_max[] = {
 	[BCH_EXTENT_ENTRY_crc32] = CRC32_SIZE_MAX,
 	[BCH_EXTENT_ENTRY_crc64] = CRC64_SIZE_MAX,
@@ -687,37 +689,6 @@ unsigned bch2_bkey_durability(struct bch_fs *c, struct bkey_s_c k)
 	return durability;
 }
 
-void bch2_bkey_mark_replicas_cached(struct bch_fs *c, struct bkey_s k,
-				    unsigned target,
-				    unsigned nr_desired_replicas)
-{
-	struct bkey_ptrs ptrs = bch2_bkey_ptrs(k);
-	union bch_extent_entry *entry;
-	struct extent_ptr_decoded p;
-	int extra = bch2_bkey_durability(c, k.s_c) - nr_desired_replicas;
-
-	if (target && extra > 0)
-		bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
-			int n = bch2_extent_ptr_durability(c, p);
-
-			if (n && n <= extra &&
-			    !bch2_dev_in_target(c, p.ptr.dev, target)) {
-				entry->ptr.cached = true;
-				extra -= n;
-			}
-		}
-
-	if (extra > 0)
-		bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
-			int n = bch2_extent_ptr_durability(c, p);
-
-			if (n && n <= extra) {
-				entry->ptr.cached = true;
-				extra -= n;
-			}
-		}
-}
-
 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));
@@ -821,8 +792,8 @@ static void extent_entry_drop(struct bkey_s k, union bch_extent_entry *entry)
 /*
  * Returns pointer to the next entry after the one being dropped:
  */
-union bch_extent_entry *__bch2_bkey_drop_ptr(struct bkey_s k,
-					     struct bch_extent_ptr *ptr)
+static union bch_extent_entry *__bch2_bkey_drop_ptr(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;
@@ -894,6 +865,14 @@ void bch2_bkey_drop_device(struct bkey_s k, unsigned dev)
 	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 = (void *) bch2_bkey_has_device(k.s_c, dev);
+
+	if (ptr)
+		__bch2_bkey_drop_ptr(k, ptr);
+}
+
 const struct bch_extent_ptr *
 bch2_bkey_has_device(struct bkey_s_c k, unsigned dev)
 {
@@ -939,6 +918,44 @@ bool bch2_bkey_matches_ptr(struct bch_fs *c, struct bkey_s_c k,
 }
 
 /*
+ * Returns true if two extents refer to the same data:
+ */
+bool bch2_extents_match(struct bkey_s_c k1, struct bkey_s_c k2)
+{
+	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;
+
+	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;
+}
+
+bool bch2_extent_has_ptr(struct bkey_s_c k1, struct extent_ptr_decoded p1,
+			 struct bkey_s_c k2)
+{
+	struct bkey_ptrs_c ptrs2 = bch2_bkey_ptrs_c(k2);
+	const 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 true;
+
+	return false;
+}
+
+/*
  * bch_extent_normalize - clean up an extent, dropping stale pointers etc.
  *
  * Returns true if @k should be dropped entirely