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 6d14d876cf57b0b5bf761dfca0a32e4b29d27e45..41adb097b8239eaac03293b27b905ae87ae46ed4 100644 (file)
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1606,11 +1606,11 @@ 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);