From: Samuel Just <sjust@redhat.com>
Date: Fri, 8 Apr 2022 09:20:49 +0000 (-0700)
Subject: crimson/os/seastore/object_data_handler: don't return empty buffers from split_pin*
X-Git-Tag: v18.0.0~1076^2~1
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=88319b475f5d09b2dee2c31f326b11f89dac7771;p=ceph.git

crimson/os/seastore/object_data_handler: don't return empty buffers from split_pin*

Always return std::nullopt rather than an empty buffer -- this way users
can rely on this as an invariant.

Signed-off-by: Samuel Just <sjust@redhat.com>
---

diff --git a/src/crimson/os/seastore/object_data_handler.cc b/src/crimson/os/seastore/object_data_handler.cc
index fb50b633e87..228360e3e08 100644
--- a/src/crimson/os/seastore/object_data_handler.cc
+++ b/src/crimson/os/seastore/object_data_handler.cc
@@ -177,7 +177,10 @@ split_ret split_pin_left(context_t ctx, LBAPinRef &pin, laddr_t offset)
       (zero_extent_len == 0
        ? std::nullopt
        : std::make_optional(extent_to_write_t(pin_offset, zero_extent_len))),
-      bufferptr(ceph::buffer::create(zero_prepend_len, 0))
+      (zero_prepend_len == 0
+       ? std::nullopt
+       : std::make_optional(
+	 bufferptr(ceph::buffer::create(zero_prepend_len, 0))))
     );
   } else {
     // Data, return up to offset to prepend
@@ -213,7 +216,10 @@ split_ret split_pin_right(context_t ctx, LBAPinRef &pin, laddr_t end)
       (zero_extent_len == 0
        ? std::nullopt
        : std::make_optional(extent_to_write_t(aligned_end, zero_extent_len))),
-      bufferptr(ceph::buffer::create(zero_suffix_len, 0))
+      (zero_suffix_len == 0
+       ? std::nullopt
+       : std::make_optional(
+	 bufferptr(ceph::buffer::create(zero_suffix_len, 0))))
     );
   } else {
     return read_pin(ctx, pin->duplicate()