diff options
| author | Max Reitz <mreitz@redhat.com> | 2019-09-18 11:51:43 +0200 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2019-10-28 12:08:45 +0100 |
| commit | e8d04f92378c2de7b464e04469a657fd37eb29ea (patch) | |
| tree | 0a274a9f3c9716def5230a4f09463e9d23fdd432 /block/qed.c | |
| parent | e61a28a9b6b43da6a7a48f6d325fceadf9769388 (diff) | |
block: Pass truncate exact=true where reasonable
This is a change in behavior, so all instances need a good
justification. The comments added here should explain my reasoning.
qed already had a comment that suggests it always expected
bdrv_truncate()/blk_truncate() to behave as if exact=true were passed
(c743849bee7 came eight months before 55b949c8476), so it was simply
broken until now.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190918095144.955-8-mreitz@redhat.com
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
[mreitz: Changed comment in qed.c to explain why a new QED file must be
empty, as requested and suggested by Maxim]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block/qed.c')
| -rw-r--r-- | block/qed.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/block/qed.c b/block/qed.c index 7c2a65af40..d8c4e5fb1e 100644 --- a/block/qed.c +++ b/block/qed.c @@ -673,8 +673,11 @@ static int coroutine_fn bdrv_qed_co_create(BlockdevCreateOptions *opts, l1_size = header.cluster_size * header.table_size; - /* File must start empty and grow, check truncate is supported */ - ret = blk_truncate(blk, 0, false, PREALLOC_MODE_OFF, errp); + /* + * The QED format associates file length with allocation status, + * so a new file (which is empty) must have a length of 0. + */ + ret = blk_truncate(blk, 0, true, PREALLOC_MODE_OFF, errp); if (ret < 0) { goto out; } |