From: Kent Overstreet <kent.overstreet@gmail.com>
Date: Mon, 17 May 2021 20:43:30 +0000 (-0400)
Subject: bcachefs: Fix for bch2_bkey_pack_pos() not initializing len/version fields
X-Git-Tag: Ubuntu-6.8.0-17.17~2238^2~1575
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=c21d5377791d94fca0d990eee82111572412640c;p=mirror_ubuntu-kernels.git

bcachefs: Fix for bch2_bkey_pack_pos() not initializing len/version fields

This bug led to push_whiteout() generating whiteouts that failed
bch2_bkey_invalid() due to nonzero length fields - oops.

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

diff --git a/fs/bcachefs/bkey.c b/fs/bcachefs/bkey.c
index a0379f980f7e..5de88a93f33f 100644
--- a/fs/bcachefs/bkey.c
+++ b/fs/bcachefs/bkey.c
@@ -446,8 +446,15 @@ enum bkey_pack_pos_ret bch2_bkey_pack_pos_lossy(struct bkey_packed *out,
 	struct bpos orig = in;
 #endif
 	bool exact = true;
+	unsigned i;
 
-	*w = 0;
+	/*
+	 * bch2_bkey_pack_key() will write to all of f->key_u64s, minus the 3
+	 * byte header, but pack_pos() won't if the len/version fields are big
+	 * enough - we need to make sure to zero them out:
+	 */
+	for (i = 0; i < f->key_u64s; i++)
+		w[i] = 0;
 
 	if (unlikely(in.snapshot <
 		     le64_to_cpu(f->field_offset[BKEY_FIELD_SNAPSHOT]))) {