btrfs: zero the buffer before marking it dirty in btrfs_redirty_list_add

commit c83b56d1dd87cf67492bb770c26d6f87aee70ed6 upstream.

btrfs_redirty_list_add zeroes the buffer data and sets the
EXTENT_BUFFER_NO_CHECK to make sure writeback is fine with a bogus
header.  But it does that after already marking the buffer dirty, which
means that writeback could already be looking at the buffer.

Switch the order of operations around so that the buffer is only marked
dirty when we're ready to write it.

Fixes: d3575156f662 ("btrfs: zoned: redirty released extent buffers")
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 38ea89d9d61fe5280fca965f93911b6ae3a049cf..8c858f31bdbc0fc96079032bb6fb47cd3890d777 100644 (file)
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1347,11 +1347,11 @@ void btrfs_redirty_list_add(struct btrfs_transaction *trans,
            !list_empty(&eb->release_list))
                return;
 
+       memzero_extent_buffer(eb, 0, eb->len);
+       set_bit(EXTENT_BUFFER_NO_CHECK, &eb->bflags);
        set_extent_buffer_dirty(eb);
        set_extent_bits_nowait(&trans->dirty_pages, eb->start,
                               eb->start + eb->len - 1, EXTENT_DIRTY);
-       memzero_extent_buffer(eb, 0, eb->len);
-       set_bit(EXTENT_BUFFER_NO_CHECK, &eb->bflags);
 
        spin_lock(&trans->releasing_ebs_lock);
        list_add_tail(&eb->release_list, &trans->releasing_ebs);