reftable: adapt write_object_record() to propagate block_writer_add() errors

Previously, write_object_record() would flush the current block and retry
appending the record whenever block_writer_add() returned any nonzero
error. This forced an assumption that every failure meant the block was
full, even when errors such as memory allocation or I/O failures occurred.

Update the write_object_record() to inspect the error code returned by
block_writer_add() and flush and reinitialize the writer iff the
error is REFTABLE_ENTRY_TOO_BIG_ERROR. For any other error, immediately
propagate it.

If the flush and reinitialization still fail with
REFTABLE_ENTRY_TOO_BIG_ERROR, reset the record's offset length to zero
before a final attempt.

All call sites now handle various error codes returned by
block_writer_add().

Signed-off-by: Meet Soni <meetsoni3017@gmail.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/reftable/writer.c b/reftable/writer.c
index 94c97b7ac0505989f46478c090e995cc80db6443..f48e7cc2904ea4f1403188263842b80fb5e157fc 100644 (file)
--- a/reftable/writer.c
+++ b/reftable/writer.c
@@ -620,10 +620,22 @@ static void write_object_record(void *void_arg, void *key)
        if (arg->err < 0)
                goto done;
 
+       /*
+        * Try to add the record to the writer. If this succeeds then we're
+        * done. Otherwise the block writer may have hit the block size limit
+        * and needs to be flushed.
+        */
        arg->err = block_writer_add(arg->w->block_writer, &rec);
        if (arg->err == 0)
                goto done;
 
+       if (arg->err != REFTABLE_ENTRY_TOO_BIG_ERROR)
+               goto done;
+
+       /*
+        * The current block is full, so we need to flush and reinitialize the
+        * writer to start writing the next block.
+        */
        arg->err = writer_flush_block(arg->w);
        if (arg->err < 0)
                goto done;
@@ -632,10 +644,17 @@ static void write_object_record(void *void_arg, void *key)
        if (arg->err < 0)
                goto done;
 
+       /*
+        * If this still fails then we may need to reset record's offset
+        * length to reduce the data size to be written.
+        */
        arg->err = block_writer_add(arg->w->block_writer, &rec);
        if (arg->err == 0)
                goto done;
 
+       if (arg->err != REFTABLE_ENTRY_TOO_BIG_ERROR)
+               goto done;
+
        rec.u.obj.offset_len = 0;
        arg->err = block_writer_add(arg->w->block_writer, &rec);