From a5e3dce493d4b12b74000b6a99b6712afa5d1a4d Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Fri, 22 Mar 2024 00:15:41 -0400
Subject: bcachefs: Fix assert in bch2_backpointer_invalid()

Backpointers that point to invalid devices are caught by fsck, not
.key_invalid; so .key_invalid needs to check for them instead of hitting
asserts.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 fs/bcachefs/backpointers.c | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'fs/bcachefs/backpointers.c')

diff --git a/fs/bcachefs/backpointers.c b/fs/bcachefs/backpointers.c
index 8cb35ea572cb..21b3ae7df824 100644
--- a/fs/bcachefs/backpointers.c
+++ b/fs/bcachefs/backpointers.c
@@ -44,6 +44,11 @@ int bch2_backpointer_invalid(struct bch_fs *c, struct bkey_s_c k,
 			     struct printbuf *err)
 {
 	struct bkey_s_c_backpointer bp = bkey_s_c_to_backpointer(k);
+
+	/* these will be caught by fsck */
+	if (!bch2_dev_exists2(c, bp.k->p.inode))
+		return 0;
+
 	struct bpos bucket = bp_pos_to_bucket(c, bp.k->p);
 	int ret = 0;
 
-- 
cgit v1.2.3-70-g09d2


From 47d2080e30b0b9fc636eba4e74f9e4bdc01543d7 Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Mon, 25 Mar 2024 19:26:05 -0400
Subject: bcachefs: Kill bch2_bkey_ptr_data_type()

Remove some duplication, and inconsistency between check_fix_ptrs and
the main ptr marking paths

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 fs/bcachefs/backpointers.c |  6 ++---
 fs/bcachefs/backpointers.h | 32 ++++++++++++++++++++-----
 fs/bcachefs/btree_gc.c     | 59 +++++++++++++++++++++++++---------------------
 fs/bcachefs/buckets.c      | 12 ++++++----
 fs/bcachefs/extents.h      | 24 -------------------
 5 files changed, 67 insertions(+), 66 deletions(-)

(limited to 'fs/bcachefs/backpointers.c')

diff --git a/fs/bcachefs/backpointers.c b/fs/bcachefs/backpointers.c
index 21b3ae7df824..7537d78aa9db 100644
--- a/fs/bcachefs/backpointers.c
+++ b/fs/bcachefs/backpointers.c
@@ -29,8 +29,7 @@ static bool extent_matches_bp(struct bch_fs *c,
 		if (p.ptr.cached)
 			continue;
 
-		bch2_extent_ptr_to_bp(c, btree_id, level, k, p,
-				      &bucket2, &bp2);
+		bch2_extent_ptr_to_bp(c, btree_id, level, k, p, entry, &bucket2, &bp2);
 		if (bpos_eq(bucket, bucket2) &&
 		    !memcmp(&bp, &bp2, sizeof(bp)))
 			return true;
@@ -507,8 +506,7 @@ static int check_extent_to_backpointers(struct btree_trans *trans,
 		if (p.ptr.cached)
 			continue;
 
-		bch2_extent_ptr_to_bp(c, btree, level,
-				      k, p, &bucket_pos, &bp);
+		bch2_extent_ptr_to_bp(c, btree, level, k, p, entry, &bucket_pos, &bp);
 
 		ret = check_bp_exists(trans, s, bucket_pos, bp, k);
 		if (ret)
diff --git a/fs/bcachefs/backpointers.h b/fs/bcachefs/backpointers.h
index 327365a9feac..da012ca7daee 100644
--- a/fs/bcachefs/backpointers.h
+++ b/fs/bcachefs/backpointers.h
@@ -90,20 +90,40 @@ static inline int bch2_bucket_backpointer_mod(struct btree_trans *trans,
 	return bch2_trans_update_buffered(trans, BTREE_ID_backpointers, &bp_k.k_i);
 }
 
-static inline enum bch_data_type bkey_ptr_data_type(enum btree_id btree_id, unsigned level,
-						    struct bkey_s_c k, struct extent_ptr_decoded p)
+static inline enum bch_data_type bch2_bkey_ptr_data_type(struct bkey_s_c k,
+							 struct extent_ptr_decoded p,
+							 const union bch_extent_entry *entry)
 {
-	return  level		? BCH_DATA_btree :
-		p.has_ec	? BCH_DATA_stripe :
-				  BCH_DATA_user;
+	switch (k.k->type) {
+	case KEY_TYPE_btree_ptr:
+	case KEY_TYPE_btree_ptr_v2:
+		return BCH_DATA_btree;
+	case KEY_TYPE_extent:
+	case KEY_TYPE_reflink_v:
+		return p.has_ec ? BCH_DATA_stripe : BCH_DATA_user;
+	case KEY_TYPE_stripe: {
+		const struct bch_extent_ptr *ptr = &entry->ptr;
+		struct bkey_s_c_stripe s = bkey_s_c_to_stripe(k);
+
+		BUG_ON(ptr < s.v->ptrs ||
+		       ptr >= s.v->ptrs + s.v->nr_blocks);
+
+		return ptr >= s.v->ptrs + s.v->nr_blocks - s.v->nr_redundant
+			? BCH_DATA_parity
+			: BCH_DATA_user;
+	}
+	default:
+		BUG();
+	}
 }
 
 static inline void bch2_extent_ptr_to_bp(struct bch_fs *c,
 			   enum btree_id btree_id, unsigned level,
 			   struct bkey_s_c k, struct extent_ptr_decoded p,
+			   const union bch_extent_entry *entry,
 			   struct bpos *bucket_pos, struct bch_backpointer *bp)
 {
-	enum bch_data_type data_type = bkey_ptr_data_type(btree_id, level, k, p);
+	enum bch_data_type data_type = bch2_bkey_ptr_data_type(k, p, entry);
 	s64 sectors = level ? btree_sectors(c) : k.k->size;
 	u32 bucket_offset;
 
diff --git a/fs/bcachefs/btree_gc.c b/fs/bcachefs/btree_gc.c
index 26e51af9acdc..0afefccf4e52 100644
--- a/fs/bcachefs/btree_gc.c
+++ b/fs/bcachefs/btree_gc.c
@@ -7,6 +7,7 @@
 #include "bcachefs.h"
 #include "alloc_background.h"
 #include "alloc_foreground.h"
+#include "backpointers.h"
 #include "bkey_methods.h"
 #include "bkey_buf.h"
 #include "btree_journal_iter.h"
@@ -508,7 +509,7 @@ static int bch2_check_fix_ptrs(struct btree_trans *trans, enum btree_id btree_id
 	bkey_for_each_ptr_decode(k->k, ptrs_c, p, entry_c) {
 		struct bch_dev *ca = bch_dev_bkey_exists(c, p.ptr.dev);
 		struct bucket *g = PTR_GC_BUCKET(ca, &p.ptr);
-		enum bch_data_type data_type = bch2_bkey_ptr_data_type(*k, &entry_c->ptr);
+		enum bch_data_type data_type = bch2_bkey_ptr_data_type(*k, p, entry_c);
 
 		if (fsck_err_on(!g->gen_valid,
 				c, ptr_to_missing_alloc_key,
@@ -574,7 +575,8 @@ static int bch2_check_fix_ptrs(struct btree_trans *trans, enum btree_id btree_id
 			continue;
 
 		if (fsck_err_on(bucket_data_type(g->data_type) &&
-				bucket_data_type(g->data_type) != data_type, c,
+				bucket_data_type(g->data_type) !=
+				bucket_data_type(data_type), c,
 				ptr_bucket_data_type_mismatch,
 				"bucket %u:%zu different types of data in same bucket: %s, %s\n"
 				"while marking %s",
@@ -615,18 +617,13 @@ static int bch2_check_fix_ptrs(struct btree_trans *trans, enum btree_id btree_id
 	}
 
 	if (do_update) {
-		struct bkey_ptrs ptrs;
-		union bch_extent_entry *entry;
-		struct bch_extent_ptr *ptr;
-		struct bkey_i *new;
-
 		if (is_root) {
 			bch_err(c, "cannot update btree roots yet");
 			ret = -EINVAL;
 			goto err;
 		}
 
-		new = kmalloc(bkey_bytes(k->k), GFP_KERNEL);
+		struct bkey_i *new = kmalloc(bkey_bytes(k->k), GFP_KERNEL);
 		if (!new) {
 			ret = -BCH_ERR_ENOMEM_gc_repair_key;
 			bch_err_msg(c, ret, "allocating new key");
@@ -641,7 +638,7 @@ static int bch2_check_fix_ptrs(struct btree_trans *trans, enum btree_id btree_id
 			 * btree node isn't there anymore, the read path will
 			 * sort it out:
 			 */
-			ptrs = bch2_bkey_ptrs(bkey_i_to_s(new));
+			struct bkey_ptrs ptrs = bch2_bkey_ptrs(bkey_i_to_s(new));
 			bkey_for_each_ptr(ptrs, ptr) {
 				struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
 				struct bucket *g = PTR_GC_BUCKET(ca, ptr);
@@ -649,19 +646,26 @@ static int bch2_check_fix_ptrs(struct btree_trans *trans, enum btree_id btree_id
 				ptr->gen = g->gen;
 			}
 		} else {
-			bch2_bkey_drop_ptrs(bkey_i_to_s(new), ptr, ({
-				struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
-				struct bucket *g = PTR_GC_BUCKET(ca, ptr);
-				enum bch_data_type data_type = bch2_bkey_ptr_data_type(*k, ptr);
-
-				(ptr->cached &&
-				 (!g->gen_valid || gen_cmp(ptr->gen, g->gen) > 0)) ||
-				(!ptr->cached &&
-				 gen_cmp(ptr->gen, g->gen) < 0) ||
-				gen_cmp(g->gen, ptr->gen) > BUCKET_GC_GEN_MAX ||
-				(g->data_type &&
-				 g->data_type != data_type);
-			}));
+			struct bkey_ptrs ptrs;
+			union bch_extent_entry *entry;
+restart_drop_ptrs:
+			ptrs = bch2_bkey_ptrs(bkey_i_to_s(new));
+			bkey_for_each_ptr_decode(bkey_i_to_s(new).k, ptrs, p, entry) {
+				struct bch_dev *ca = bch_dev_bkey_exists(c, p.ptr.dev);
+				struct bucket *g = PTR_GC_BUCKET(ca, &p.ptr);
+				enum bch_data_type data_type = bch2_bkey_ptr_data_type(bkey_i_to_s_c(new), p, entry);
+
+				if ((p.ptr.cached &&
+				     (!g->gen_valid || gen_cmp(p.ptr.gen, g->gen) > 0)) ||
+				    (!p.ptr.cached &&
+				     gen_cmp(p.ptr.gen, g->gen) < 0) ||
+				    gen_cmp(g->gen, p.ptr.gen) > BUCKET_GC_GEN_MAX ||
+				    (g->data_type &&
+				     g->data_type != data_type)) {
+					bch2_bkey_drop_ptr(bkey_i_to_s(new), &entry->ptr);
+					goto restart_drop_ptrs;
+				}
+			}
 again:
 			ptrs = bch2_bkey_ptrs(bkey_i_to_s(new));
 			bkey_extent_entry_for_each(ptrs, entry) {
@@ -736,10 +740,6 @@ static int bch2_gc_mark_key(struct btree_trans *trans, enum btree_id btree_id,
 		BUG_ON(bch2_journal_seq_verify &&
 		       k->k->version.lo > atomic64_read(&c->journal.seq));
 
-		ret = bch2_check_fix_ptrs(trans, btree_id, level, is_root, k);
-		if (ret)
-			goto err;
-
 		if (fsck_err_on(k->k->version.lo > atomic64_read(&c->key_version), c,
 				bkey_version_in_future,
 				"key version number higher than recorded: %llu > %llu",
@@ -748,8 +748,13 @@ static int bch2_gc_mark_key(struct btree_trans *trans, enum btree_id btree_id,
 			atomic64_set(&c->key_version, k->k->version.lo);
 	}
 
+	ret = bch2_check_fix_ptrs(trans, btree_id, level, is_root, k);
+	if (ret)
+		goto err;
+
 	ret = commit_do(trans, NULL, NULL, 0,
-			bch2_key_trigger(trans, btree_id, level, old, unsafe_bkey_s_c_to_s(*k), BTREE_TRIGGER_GC));
+			bch2_key_trigger(trans, btree_id, level, old,
+					 unsafe_bkey_s_c_to_s(*k), BTREE_TRIGGER_GC));
 fsck_err:
 err:
 	bch_err_fn(c, ret);
diff --git a/fs/bcachefs/buckets.c b/fs/bcachefs/buckets.c
index 96edf2c34d43..941401a210f5 100644
--- a/fs/bcachefs/buckets.c
+++ b/fs/bcachefs/buckets.c
@@ -525,6 +525,7 @@ int bch2_mark_metadata_bucket(struct bch_fs *c, struct bch_dev *ca,
 			"different types of data in same bucket: %s, %s",
 			bch2_data_type_str(g->data_type),
 			bch2_data_type_str(data_type))) {
+		BUG();
 		ret = -EIO;
 		goto err;
 	}
@@ -628,6 +629,7 @@ int bch2_check_bucket_ref(struct btree_trans *trans,
 			bch2_data_type_str(ptr_data_type),
 			(printbuf_reset(&buf),
 			 bch2_bkey_val_to_text(&buf, c, k), buf.buf));
+		BUG();
 		ret = -EIO;
 		goto err;
 	}
@@ -815,14 +817,14 @@ static int __mark_pointer(struct btree_trans *trans,
 static int bch2_trigger_pointer(struct btree_trans *trans,
 			enum btree_id btree_id, unsigned level,
 			struct bkey_s_c k, struct extent_ptr_decoded p,
-			s64 *sectors,
-			unsigned flags)
+			const union bch_extent_entry *entry,
+			s64 *sectors, unsigned flags)
 {
 	bool insert = !(flags & BTREE_TRIGGER_OVERWRITE);
 	struct bpos bucket;
 	struct bch_backpointer bp;
 
-	bch2_extent_ptr_to_bp(trans->c, btree_id, level, k, p, &bucket, &bp);
+	bch2_extent_ptr_to_bp(trans->c, btree_id, level, k, p, entry, &bucket, &bp);
 	*sectors = insert ? bp.bucket_len : -((s64) bp.bucket_len);
 
 	if (flags & BTREE_TRIGGER_TRANSACTIONAL) {
@@ -851,7 +853,7 @@ static int bch2_trigger_pointer(struct btree_trans *trans,
 	if (flags & BTREE_TRIGGER_GC) {
 		struct bch_fs *c = trans->c;
 		struct bch_dev *ca = bch_dev_bkey_exists(c, p.ptr.dev);
-		enum bch_data_type data_type = bkey_ptr_data_type(btree_id, level, k, p);
+		enum bch_data_type data_type = bch2_bkey_ptr_data_type(k, p, entry);
 
 		percpu_down_read(&c->mark_lock);
 		struct bucket *g = PTR_GC_BUCKET(ca, &p.ptr);
@@ -979,7 +981,7 @@ static int __trigger_extent(struct btree_trans *trans,
 
 	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 		s64 disk_sectors;
-		ret = bch2_trigger_pointer(trans, btree_id, level, k, p, &disk_sectors, flags);
+		ret = bch2_trigger_pointer(trans, btree_id, level, k, p, entry, &disk_sectors, flags);
 		if (ret < 0)
 			return ret;
 
diff --git a/fs/bcachefs/extents.h b/fs/bcachefs/extents.h
index fd2669cdd76f..3fd0169b98c1 100644
--- a/fs/bcachefs/extents.h
+++ b/fs/bcachefs/extents.h
@@ -596,30 +596,6 @@ static inline struct bch_devs_list bch2_bkey_cached_devs(struct bkey_s_c k)
 	return ret;
 }
 
-static inline unsigned bch2_bkey_ptr_data_type(struct bkey_s_c k, const struct bch_extent_ptr *ptr)
-{
-	switch (k.k->type) {
-	case KEY_TYPE_btree_ptr:
-	case KEY_TYPE_btree_ptr_v2:
-		return BCH_DATA_btree;
-	case KEY_TYPE_extent:
-	case KEY_TYPE_reflink_v:
-		return BCH_DATA_user;
-	case KEY_TYPE_stripe: {
-		struct bkey_s_c_stripe s = bkey_s_c_to_stripe(k);
-
-		BUG_ON(ptr < s.v->ptrs ||
-		       ptr >= s.v->ptrs + s.v->nr_blocks);
-
-		return ptr >= s.v->ptrs + s.v->nr_blocks - s.v->nr_redundant
-			? BCH_DATA_parity
-			: BCH_DATA_user;
-	}
-	default:
-		BUG();
-	}
-}
-
 unsigned bch2_bkey_nr_ptrs(struct bkey_s_c);
 unsigned bch2_bkey_nr_ptrs_allocated(struct bkey_s_c);
 unsigned bch2_bkey_nr_ptrs_fully_allocated(struct bkey_s_c);
-- 
cgit v1.2.3-70-g09d2


From 11d5568d3e04a2e6734d1eccc394cfcf5ca8523c Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Thu, 28 Mar 2024 01:41:03 -0400
Subject: bcachefs: fix backpointer for missing alloc key msg

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 fs/bcachefs/backpointers.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'fs/bcachefs/backpointers.c')

diff --git a/fs/bcachefs/backpointers.c b/fs/bcachefs/backpointers.c
index 7537d78aa9db..762c8ddfc5e7 100644
--- a/fs/bcachefs/backpointers.c
+++ b/fs/bcachefs/backpointers.c
@@ -382,7 +382,7 @@ static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_
 			backpointer_to_missing_alloc,
 			"backpointer for nonexistent alloc key: %llu:%llu:0\n%s",
 			alloc_iter.pos.inode, alloc_iter.pos.offset,
-			(bch2_bkey_val_to_text(&buf, c, alloc_k), buf.buf))) {
+			(bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
 		ret = bch2_btree_delete_at(trans, bp_iter, 0);
 		goto out;
 	}
-- 
cgit v1.2.3-70-g09d2


From 4c02e63dadc7f5a92732ce3e267d0511749f60fb Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Sat, 30 Mar 2024 18:43:00 -0400
Subject: bcachefs: Check for extents that point to same space

In backpointer repair, if we get a missing backpointer - but there's
already a backpointer that points to an existing extent - we've got
multiple extents that point to the same space and need to decide which
to keep.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 fs/bcachefs/backpointers.c    | 173 ++++++++++++++++++++++++++++++++++++++++--
 fs/bcachefs/sb-errors_types.h |   3 +-
 2 files changed, 168 insertions(+), 8 deletions(-)

(limited to 'fs/bcachefs/backpointers.c')

diff --git a/fs/bcachefs/backpointers.c b/fs/bcachefs/backpointers.c
index 762c8ddfc5e7..114328acde72 100644
--- a/fs/bcachefs/backpointers.c
+++ b/fs/bcachefs/backpointers.c
@@ -8,6 +8,7 @@
 #include "btree_update.h"
 #include "btree_update_interior.h"
 #include "btree_write_buffer.h"
+#include "checksum.h"
 #include "error.h"
 
 #include <linux/mm.h>
@@ -418,6 +419,84 @@ struct extents_to_bp_state {
 	struct bkey_buf last_flushed;
 };
 
+static int drop_dev_and_update(struct btree_trans *trans, enum btree_id btree,
+			       struct bkey_s_c extent, unsigned dev)
+{
+	struct bkey_i *n = bch2_bkey_make_mut_noupdate(trans, extent);
+	int ret = PTR_ERR_OR_ZERO(n);
+	if (ret)
+		return ret;
+
+	bch2_bkey_drop_device(bkey_i_to_s(n), dev);
+	return bch2_btree_insert_trans(trans, btree, n, 0);
+}
+
+static int check_extent_checksum(struct btree_trans *trans,
+				 enum btree_id btree, struct bkey_s_c extent,
+				 enum btree_id o_btree, struct bkey_s_c extent2, unsigned dev)
+{
+	struct bch_fs *c = trans->c;
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(extent);
+	const union bch_extent_entry *entry;
+	struct extent_ptr_decoded p;
+	struct printbuf buf = PRINTBUF;
+	void *data_buf = NULL;
+	struct bio *bio = NULL;
+	size_t bytes;
+	int ret = 0;
+
+	if (bkey_is_btree_ptr(extent.k))
+		return false;
+
+	bkey_for_each_ptr_decode(extent.k, ptrs, p, entry)
+		if (p.ptr.dev == dev)
+			goto found;
+	BUG();
+found:
+	if (!p.crc.csum_type)
+		return false;
+
+	bytes = p.crc.compressed_size << 9;
+
+	struct bch_dev *ca = bch_dev_bkey_exists(c, dev);
+	if (!bch2_dev_get_ioref(ca, READ))
+		return false;
+
+	data_buf = kvmalloc(bytes, GFP_KERNEL);
+	if (!data_buf) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	bio = bio_alloc(ca->disk_sb.bdev, 1, REQ_OP_READ, GFP_KERNEL);
+	bio->bi_iter.bi_sector = p.ptr.offset;
+	bch2_bio_map(bio, data_buf, bytes);
+	ret = submit_bio_wait(bio);
+	if (ret)
+		goto err;
+
+	prt_str(&buf, "extents pointing to same space, but first extent checksum bad:");
+	prt_printf(&buf, "\n  %s ", bch2_btree_id_str(btree));
+	bch2_bkey_val_to_text(&buf, c, extent);
+	prt_printf(&buf, "\n  %s ", bch2_btree_id_str(o_btree));
+	bch2_bkey_val_to_text(&buf, c, extent2);
+
+	struct nonce nonce = extent_nonce(extent.k->version, p.crc);
+	struct bch_csum csum = bch2_checksum(c, p.crc.csum_type, nonce, data_buf, bytes);
+	if (fsck_err_on(bch2_crc_cmp(csum, p.crc.csum),
+			c, dup_backpointer_to_bad_csum_extent,
+			"%s", buf.buf))
+		ret = drop_dev_and_update(trans, btree, extent, dev) ?: 1;
+fsck_err:
+err:
+	if (bio)
+		bio_put(bio);
+	kvfree(data_buf);
+	percpu_ref_put(&ca->io_ref);
+	printbuf_exit(&buf);
+	return ret;
+}
+
 static int check_bp_exists(struct btree_trans *trans,
 			   struct extents_to_bp_state *s,
 			   struct bpos bucket,
@@ -425,7 +504,8 @@ static int check_bp_exists(struct btree_trans *trans,
 			   struct bkey_s_c orig_k)
 {
 	struct bch_fs *c = trans->c;
-	struct btree_iter bp_iter = { NULL };
+	struct btree_iter bp_iter = {};
+	struct btree_iter other_extent_iter = {};
 	struct printbuf buf = PRINTBUF;
 	struct bkey_s_c bp_k;
 	struct bkey_buf tmp;
@@ -433,13 +513,19 @@ static int check_bp_exists(struct btree_trans *trans,
 
 	bch2_bkey_buf_init(&tmp);
 
+	if (!bch2_dev_bucket_exists(c, bucket)) {
+		prt_str(&buf, "extent for nonexistent device:bucket ");
+		bch2_bpos_to_text(&buf, bucket);
+		prt_str(&buf, "\n  ");
+		bch2_bkey_val_to_text(&buf, c, orig_k);
+		bch_err(c, "%s", buf.buf);
+		return -BCH_ERR_fsck_repair_unimplemented;
+	}
+
 	if (bpos_lt(bucket, s->bucket_start) ||
 	    bpos_gt(bucket, s->bucket_end))
 		return 0;
 
-	if (!bch2_dev_bucket_exists(c, bucket))
-		goto missing;
-
 	bp_k = bch2_bkey_get_iter(trans, &bp_iter, BTREE_ID_backpointers,
 				  bucket_pos_to_bp(c, bucket, bp.bucket_offset),
 				  0);
@@ -465,21 +551,94 @@ static int check_bp_exists(struct btree_trans *trans,
 			ret = -BCH_ERR_transaction_restart_write_buffer_flush;
 			goto out;
 		}
-		goto missing;
+
+		goto check_existing_bp;
 	}
 out:
 err:
 fsck_err:
+	bch2_trans_iter_exit(trans, &other_extent_iter);
 	bch2_trans_iter_exit(trans, &bp_iter);
 	bch2_bkey_buf_exit(&tmp, c);
 	printbuf_exit(&buf);
 	return ret;
+check_existing_bp:
+	/* Do we have a backpointer for a different extent? */
+	if (bp_k.k->type != KEY_TYPE_backpointer)
+		goto missing;
+
+	struct bch_backpointer other_bp = *bkey_s_c_to_backpointer(bp_k).v;
+
+	struct bkey_s_c other_extent =
+		bch2_backpointer_get_key(trans, &other_extent_iter, bp_k.k->p, other_bp, 0);
+	ret = bkey_err(other_extent);
+	if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node)
+		ret = 0;
+	if (ret)
+		goto err;
+
+	if (!other_extent.k)
+		goto missing;
+
+	if (bch2_extents_match(orig_k, other_extent)) {
+		printbuf_reset(&buf);
+		prt_printf(&buf, "duplicate versions of same extent, deleting smaller\n  ");
+		bch2_bkey_val_to_text(&buf, c, orig_k);
+		prt_str(&buf, "\n  ");
+		bch2_bkey_val_to_text(&buf, c, other_extent);
+		bch_err(c, "%s", buf.buf);
+
+		if (other_extent.k->size <= orig_k.k->size) {
+			ret = drop_dev_and_update(trans, other_bp.btree_id, other_extent, bucket.inode);
+			if (ret)
+				goto err;
+			goto out;
+		} else {
+			ret = drop_dev_and_update(trans, bp.btree_id, orig_k, bucket.inode);
+			if (ret)
+				goto err;
+			goto missing;
+		}
+	}
+
+	ret = check_extent_checksum(trans, other_bp.btree_id, other_extent, bp.btree_id, orig_k, bucket.inode);
+	if (ret < 0)
+		goto err;
+	if (ret) {
+		ret = 0;
+		goto missing;
+	}
+
+	ret = check_extent_checksum(trans, bp.btree_id, orig_k, other_bp.btree_id, other_extent, bucket.inode);
+	if (ret < 0)
+		goto err;
+	if (ret) {
+		ret = 0;
+		goto out;
+	}
+
+	printbuf_reset(&buf);
+	prt_printf(&buf, "duplicate extents pointing to same space on dev %llu\n  ", bucket.inode);
+	bch2_bkey_val_to_text(&buf, c, orig_k);
+	prt_str(&buf, "\n  ");
+	bch2_bkey_val_to_text(&buf, c, other_extent);
+	bch_err(c, "%s", buf.buf);
+	ret = -BCH_ERR_fsck_repair_unimplemented;
+	goto err;
 missing:
+	printbuf_reset(&buf);
 	prt_printf(&buf, "missing backpointer for btree=%s l=%u ",
 	       bch2_btree_id_str(bp.btree_id), bp.level);
 	bch2_bkey_val_to_text(&buf, c, orig_k);
-	prt_printf(&buf, "\nbp pos ");
-	bch2_bpos_to_text(&buf, bp_iter.pos);
+	prt_printf(&buf, "\n  got:   ");
+	bch2_bkey_val_to_text(&buf, c, bp_k);
+
+	struct bkey_i_backpointer n_bp_k;
+	bkey_backpointer_init(&n_bp_k.k_i);
+	n_bp_k.k.p = bucket_pos_to_bp(trans->c, bucket, bp.bucket_offset);
+	n_bp_k.v = bp;
+	prt_printf(&buf, "\n  want:  ");
+	bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&n_bp_k.k_i));
 
 	if (fsck_err(c, ptr_to_missing_backpointer, "%s", buf.buf))
 		ret = bch2_bucket_backpointer_mod(trans, bucket, bp, orig_k, true);
diff --git a/fs/bcachefs/sb-errors_types.h b/fs/bcachefs/sb-errors_types.h
index 2f8f4d2388b0..d7d609131030 100644
--- a/fs/bcachefs/sb-errors_types.h
+++ b/fs/bcachefs/sb-errors_types.h
@@ -269,7 +269,8 @@
 	x(btree_node_topology_empty_interior_node,		261)	\
 	x(btree_ptr_v2_min_key_bad,				262)	\
 	x(btree_root_unreadable_and_scan_found_nothing,		263)	\
-	x(snapshot_node_missing,				264)
+	x(snapshot_node_missing,				264)	\
+	x(dup_backpointer_to_bad_csum_extent,			265)
 
 enum bch_sb_error_id {
 #define x(t, n) BCH_FSCK_ERR_##t = n,
-- 
cgit v1.2.3-70-g09d2


From f0a73d4fde5b285d94a702026216d9fd1fd2733d Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Sun, 14 Apr 2024 00:51:48 -0400
Subject: bcachefs: Check for backpointer bucket_offset >= bucket size

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 fs/bcachefs/backpointers.c    | 8 +++++---
 fs/bcachefs/backpointers.h    | 9 +++------
 fs/bcachefs/sb-errors_types.h | 2 +-
 3 files changed, 9 insertions(+), 10 deletions(-)

(limited to 'fs/bcachefs/backpointers.c')

diff --git a/fs/bcachefs/backpointers.c b/fs/bcachefs/backpointers.c
index 114328acde72..fadb1078903d 100644
--- a/fs/bcachefs/backpointers.c
+++ b/fs/bcachefs/backpointers.c
@@ -49,13 +49,15 @@ int bch2_backpointer_invalid(struct bch_fs *c, struct bkey_s_c k,
 	if (!bch2_dev_exists2(c, bp.k->p.inode))
 		return 0;
 
+	struct bch_dev *ca = bch_dev_bkey_exists(c, bp.k->p.inode);
 	struct bpos bucket = bp_pos_to_bucket(c, bp.k->p);
 	int ret = 0;
 
-	bkey_fsck_err_on(!bpos_eq(bp.k->p, bucket_pos_to_bp(c, bucket, bp.v->bucket_offset)),
+	bkey_fsck_err_on((bp.v->bucket_offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT) >= ca->mi.bucket_size ||
+			 !bpos_eq(bp.k->p, bucket_pos_to_bp(c, bucket, bp.v->bucket_offset)),
 			 c, err,
-			 backpointer_pos_wrong,
-			 "backpointer at wrong pos");
+			 backpointer_bucket_offset_wrong,
+			 "backpointer bucket_offset wrong");
 fsck_err:
 	return ret;
 }
diff --git a/fs/bcachefs/backpointers.h b/fs/bcachefs/backpointers.h
index da012ca7daee..85949b9fd880 100644
--- a/fs/bcachefs/backpointers.h
+++ b/fs/bcachefs/backpointers.h
@@ -53,14 +53,11 @@ static inline struct bpos bucket_pos_to_bp(const struct bch_fs *c,
 					   u64 bucket_offset)
 {
 	struct bch_dev *ca = bch_dev_bkey_exists(c, bucket.inode);
-	struct bpos ret;
-
-	ret = POS(bucket.inode,
-		  (bucket_to_sector(ca, bucket.offset) <<
-		   MAX_EXTENT_COMPRESS_RATIO_SHIFT) + bucket_offset);
+	struct bpos ret = POS(bucket.inode,
+			      (bucket_to_sector(ca, bucket.offset) <<
+			       MAX_EXTENT_COMPRESS_RATIO_SHIFT) + bucket_offset);
 
 	EBUG_ON(!bkey_eq(bucket, bp_pos_to_bucket(c, ret)));
-
 	return ret;
 }
 
diff --git a/fs/bcachefs/sb-errors_types.h b/fs/bcachefs/sb-errors_types.h
index 5b600c6d7aca..4ca6e7b0d8aa 100644
--- a/fs/bcachefs/sb-errors_types.h
+++ b/fs/bcachefs/sb-errors_types.h
@@ -130,7 +130,7 @@
 	x(bucket_gens_nonzero_for_invalid_buckets,		122)	\
 	x(need_discard_freespace_key_to_invalid_dev_bucket,	123)	\
 	x(need_discard_freespace_key_bad,			124)	\
-	x(backpointer_pos_wrong,				125)	\
+	x(backpointer_bucket_offset_wrong,			125)	\
 	x(backpointer_to_missing_device,			126)	\
 	x(backpointer_to_missing_alloc,				127)	\
 	x(backpointer_to_missing_ptr,				128)	\
-- 
cgit v1.2.3-70-g09d2