From: Mark Harmstone <mark@harmstone.com>
Date: Mon, 23 Mar 2026 12:59:57 +0000 (+0000)
Subject: btrfs: fix bytes_may_use leak in do_remap_reloc_trans()
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=9b8824533d75fb199a3fb0f6147ffcca64b5caf8;p=thirdparty%2Fkernel%2Flinux.git

btrfs: fix bytes_may_use leak in do_remap_reloc_trans()

If the call to btrfs_reserve_extent() in do_remap_reloc_trans() returns
a smaller extent than we asked for, currently we're not undoing the
bytes_may_use change that we made. Fix this by calling
btrfs_space_info_update_bytes_may_use() again for the difference.

Fixes: fd6594b1446c ("btrfs: replace identity remaps with actual remaps when doing relocations")
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 3d1756b61162..ad433b7ca919 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -5006,6 +5006,12 @@ static int do_remap_reloc_trans(struct btrfs_fs_info *fs_info,
 		return ret;
 	}
 
+	if (ins.offset < remap_length) {
+		spin_lock(&sinfo->lock);
+		btrfs_space_info_update_bytes_may_use(sinfo, ins.offset - remap_length);
+		spin_unlock(&sinfo->lock);
+	}
+
 	made_reservation = true;
 
 	new_addr = ins.objectid;