dissect: use DISKSEQ when waiting for block devices

DISKSEQ is a reliable way to find out if we missed a uevent or not, as
it's monotonically increasing. If we parse an event with a smaller or
no sequence number, we know we need to wait longer. If we parse an
event with a greater sequence number, we know we missed it and the
device was reused.
This commit is contained in:
Luca Boccassi
2021-07-28 20:07:01 +01:00
parent bcef1743a5
commit a36429971a
10 changed files with 55 additions and 18 deletions
+3 -3
View File
@@ -51,7 +51,7 @@ static void* thread_func(void *ptr) {
log_notice("Acquired loop device %s, will mount on %s", loop->node, mounted);
r = dissect_image(loop->fd, NULL, NULL, loop->uevent_seqnum_not_before, loop->timestamp_not_before, DISSECT_IMAGE_READ_ONLY, &dissected);
r = dissect_image(loop->fd, NULL, NULL, loop->diskseq, loop->uevent_seqnum_not_before, loop->timestamp_not_before, DISSECT_IMAGE_READ_ONLY, &dissected);
if (r < 0)
log_error_errno(r, "Failed dissect loopback device %s: %m", loop->node);
assert_se(r >= 0);
@@ -188,7 +188,7 @@ int main(int argc, char *argv[]) {
sfdisk = NULL;
assert_se(loop_device_make(fd, O_RDWR, 0, UINT64_MAX, LO_FLAGS_PARTSCAN, &loop) >= 0);
assert_se(dissect_image(loop->fd, NULL, NULL, loop->uevent_seqnum_not_before, loop->timestamp_not_before, 0, &dissected) >= 0);
assert_se(dissect_image(loop->fd, NULL, NULL, loop->diskseq, loop->uevent_seqnum_not_before, loop->timestamp_not_before, 0, &dissected) >= 0);
assert_se(dissected->partitions[PARTITION_ESP].found);
assert_se(dissected->partitions[PARTITION_ESP].node);
@@ -212,7 +212,7 @@ int main(int argc, char *argv[]) {
assert_se(make_filesystem(dissected->partitions[PARTITION_HOME].node, "ext4", "home", id, true) >= 0);
dissected = dissected_image_unref(dissected);
assert_se(dissect_image(loop->fd, NULL, NULL, loop->uevent_seqnum_not_before, loop->timestamp_not_before, 0, &dissected) >= 0);
assert_se(dissect_image(loop->fd, NULL, NULL, loop->diskseq, loop->uevent_seqnum_not_before, loop->timestamp_not_before, 0, &dissected) >= 0);
assert_se(mkdtemp_malloc(NULL, &mounted) >= 0);