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 | |
| 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')
| -rw-r--r-- | block/parallels.c | 11 | ||||
| -rw-r--r-- | block/qcow2.c | 6 | ||||
| -rw-r--r-- | block/qed.c | 7 |
3 files changed, 19 insertions, 5 deletions
diff --git a/block/parallels.c b/block/parallels.c index a1a92c97a4..603211f83c 100644 --- a/block/parallels.c +++ b/block/parallels.c @@ -487,7 +487,12 @@ static int coroutine_fn parallels_co_check(BlockDriverState *bs, res->leaks += count; if (fix & BDRV_FIX_LEAKS) { Error *local_err = NULL; - ret = bdrv_truncate(bs->file, res->image_end_offset, false, + + /* + * In order to really repair the image, we must shrink it. + * That means we have to pass exact=true. + */ + ret = bdrv_truncate(bs->file, res->image_end_offset, true, PREALLOC_MODE_OFF, &local_err); if (ret < 0) { error_report_err(local_err); @@ -880,7 +885,9 @@ static void parallels_close(BlockDriverState *bs) if ((bs->open_flags & BDRV_O_RDWR) && !(bs->open_flags & BDRV_O_INACTIVE)) { s->header->inuse = 0; parallels_update_header(bs); - bdrv_truncate(bs->file, s->data_end << BDRV_SECTOR_BITS, false, + + /* errors are ignored, so we might as well pass exact=true */ + bdrv_truncate(bs->file, s->data_end << BDRV_SECTOR_BITS, true, PREALLOC_MODE_OFF, NULL); } diff --git a/block/qcow2.c b/block/qcow2.c index 9f32dae41f..7c18721741 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -5323,7 +5323,11 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, return ret; } - ret = blk_truncate(blk, new_size, false, PREALLOC_MODE_OFF, errp); + /* + * Amending image options should ensure that the image has + * exactly the given new values, so pass exact=true here. + */ + ret = blk_truncate(blk, new_size, true, PREALLOC_MODE_OFF, errp); blk_unref(blk); if (ret < 0) { return ret; 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; } |