From: Luca Boccassi Date: Tue, 20 Jul 2021 14:26:56 +0000 (+0100) Subject: dissect: use DISKSEQ when waiting for block devices X-Git-Tag: v250-rc1~754^2 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=a36429971ad46af5b29d3dafba1adc596e5aaa60;p=thirdparty%2Fsystemd.git 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. --- diff --git a/src/core/namespace.c b/src/core/namespace.c index 982aeeac191..6b939e65e44 100644 --- a/src/core/namespace.c +++ b/src/core/namespace.c @@ -1905,6 +1905,7 @@ int setup_namespace( loop_device->fd, &verity, root_image_options, + loop_device->diskseq, loop_device->uevent_seqnum_not_before, loop_device->timestamp_not_before, dissect_image_flags, diff --git a/src/dissect/dissect.c b/src/dissect/dissect.c index 88bb3de40f7..f0d5da8d18b 100644 --- a/src/dissect/dissect.c +++ b/src/dissect/dissect.c @@ -795,6 +795,7 @@ static int run(int argc, char *argv[]) { arg_image, &arg_verity_settings, NULL, + d->diskseq, d->uevent_seqnum_not_before, d->timestamp_not_before, arg_flags, diff --git a/src/gpt-auto-generator/gpt-auto-generator.c b/src/gpt-auto-generator/gpt-auto-generator.c index f5346f49ad1..4d0364fceeb 100644 --- a/src/gpt-auto-generator/gpt-auto-generator.c +++ b/src/gpt-auto-generator/gpt-auto-generator.c @@ -699,6 +699,7 @@ static int enumerate_partitions(dev_t devnum) { r = dissect_image( fd, NULL, NULL, + /* diskseq= */ 0, UINT64_MAX, USEC_INFINITY, DISSECT_IMAGE_GPT_ONLY| diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c index 99a32562197..98b0b0486b1 100644 --- a/src/nspawn/nspawn.c +++ b/src/nspawn/nspawn.c @@ -5700,6 +5700,7 @@ static int run(int argc, char *argv[]) { arg_image, &arg_verity_settings, NULL, + loop->diskseq, loop->uevent_seqnum_not_before, loop->timestamp_not_before, dissect_image_flags, diff --git a/src/portable/portable.c b/src/portable/portable.c index 5afb008bb8f..899a74073d6 100644 --- a/src/portable/portable.c +++ b/src/portable/portable.c @@ -393,6 +393,7 @@ static int portable_extract_by_path( r = dissect_image( d->fd, NULL, NULL, + d->diskseq, d->uevent_seqnum_not_before, d->timestamp_not_before, DISSECT_IMAGE_READ_ONLY | diff --git a/src/shared/discover-image.c b/src/shared/discover-image.c index 521264ec29b..1711dd647af 100644 --- a/src/shared/discover-image.c +++ b/src/shared/discover-image.c @@ -1203,6 +1203,7 @@ int image_read_metadata(Image *i) { r = dissect_image( d->fd, NULL, NULL, + d->diskseq, d->uevent_seqnum_not_before, d->timestamp_not_before, DISSECT_IMAGE_GENERIC_ROOT | diff --git a/src/shared/dissect-image.c b/src/shared/dissect-image.c index 27b9ac9569e..1df1bdc3cd0 100644 --- a/src/shared/dissect-image.c +++ b/src/shared/dissect-image.c @@ -284,6 +284,7 @@ struct wait_data { sd_device *parent_device; blkid_partition blkidp; sd_device *found; + uint64_t diskseq; uint64_t uevent_seqnum_not_before; usec_t timestamp_not_before; DissectImageFlags flags; @@ -302,7 +303,25 @@ static int device_monitor_handler(sd_device_monitor *monitor, sd_device *device, if (device_for_action(device, SD_DEVICE_REMOVE)) return 0; - if (w->uevent_seqnum_not_before != UINT64_MAX) { + if (w->diskseq != 0) { + uint64_t diskseq; + + /* If w->diskseq is non-zero, then we must have a disk seqnum */ + r = sd_device_get_diskseq(device, &diskseq); + if (r < 0) { + log_debug_errno(r, "Dropping event because it has no diskseq, but waiting for %" PRIu64, w->diskseq); + return 0; + } + if (diskseq < w->diskseq) { + log_debug("Dropping event because diskseq too old (%" PRIu64 " < %" PRIu64 ")", + diskseq, w->diskseq); + return 0; + } + if (diskseq > w->diskseq) { + r = -EBUSY; + goto finish; /* Newer than what we were expecting, so we missed it, stop waiting */ + } + } else if (w->uevent_seqnum_not_before != UINT64_MAX) { uint64_t seqnum; r = sd_device_get_seqnum(device, &seqnum); @@ -378,6 +397,7 @@ static int wait_for_partition_device( sd_device *parent, blkid_partition pp, usec_t deadline, + uint64_t diskseq, uint64_t uevent_seqnum_not_before, usec_t timestamp_not_before, DissectImageFlags flags, @@ -423,6 +443,7 @@ static int wait_for_partition_device( _cleanup_(wait_data_done) struct wait_data w = { .parent_device = parent, .blkidp = pp, + .diskseq = diskseq, .uevent_seqnum_not_before = uevent_seqnum_not_before, .timestamp_not_before = timestamp_not_before, .flags = flags, @@ -450,16 +471,21 @@ static int wait_for_partition_device( return r; } - r = sd_event_add_time_relative( - event, &retry_source, - CLOCK_MONOTONIC, 500 * USEC_PER_MSEC, 0, - retry_handler, &w); - if (r < 0) - return r; + /* If we don't have a disk sequence number then we cannot do exact matching, + * and we cannot know if we missed it or if it has not been sent yet, so set + * up additional retries to increase the chances of receiving the event. */ + if (diskseq == 0) { + r = sd_event_add_time_relative( + event, &retry_source, + CLOCK_MONOTONIC, 500 * USEC_PER_MSEC, 0, + retry_handler, &w); + if (r < 0) + return r; - r = sd_event_source_set_exit_on_failure(retry_source, true); - if (r < 0) - return r; + r = sd_event_source_set_exit_on_failure(retry_source, true); + if (r < 0) + return r; + } r = sd_event_loop(event); if (r < 0) @@ -583,6 +609,7 @@ int dissect_image( int fd, const VeritySettings *verity, const MountOptions *mount_options, + uint64_t diskseq, uint64_t uevent_seqnum_not_before, usec_t timestamp_not_before, DissectImageFlags flags, @@ -838,7 +865,7 @@ int dissect_image( if (!pp) return errno_or_else(EIO); - r = wait_for_partition_device(d, pp, deadline, uevent_seqnum_not_before, timestamp_not_before, flags, &q); + r = wait_for_partition_device(d, pp, deadline, diskseq, uevent_seqnum_not_before, timestamp_not_before, flags, &q); if (r < 0) return r; @@ -2750,6 +2777,7 @@ int dissect_image_and_warn( const char *name, const VeritySettings *verity, const MountOptions *mount_options, + uint64_t diskseq, uint64_t uevent_seqnum_not_before, usec_t timestamp_not_before, DissectImageFlags flags, @@ -2766,7 +2794,7 @@ int dissect_image_and_warn( name = buffer; } - r = dissect_image(fd, verity, mount_options, uevent_seqnum_not_before, timestamp_not_before, flags, ret); + r = dissect_image(fd, verity, mount_options, diskseq, uevent_seqnum_not_before, timestamp_not_before, flags, ret); switch (r) { case -EOPNOTSUPP: @@ -2874,7 +2902,7 @@ int mount_image_privately_interactively( if (r < 0) return log_error_errno(r, "Failed to set up loopback device for %s: %m", image); - r = dissect_image_and_warn(d->fd, image, &verity, NULL, d->uevent_seqnum_not_before, d->timestamp_not_before, flags, &dissected_image); + r = dissect_image_and_warn(d->fd, image, &verity, NULL, d->diskseq, d->uevent_seqnum_not_before, d->timestamp_not_before, flags, &dissected_image); if (r < 0) return r; @@ -2965,6 +2993,7 @@ int verity_dissect_and_mount( loop_device->fd, &verity, options, + loop_device->diskseq, loop_device->uevent_seqnum_not_before, loop_device->timestamp_not_before, dissect_image_flags, @@ -2975,6 +3004,7 @@ int verity_dissect_and_mount( loop_device->fd, &verity, options, + loop_device->diskseq, loop_device->uevent_seqnum_not_before, loop_device->timestamp_not_before, dissect_image_flags | DISSECT_IMAGE_NO_PARTITION_TABLE, diff --git a/src/shared/dissect-image.h b/src/shared/dissect-image.h index 1ce14e915e2..cad52f2184c 100644 --- a/src/shared/dissect-image.h +++ b/src/shared/dissect-image.h @@ -162,8 +162,8 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(MountOptions*, mount_options_free_all); const char* mount_options_from_designator(const MountOptions *options, PartitionDesignator designator); int probe_filesystem(const char *node, char **ret_fstype); -int dissect_image(int fd, const VeritySettings *verity, const MountOptions *mount_options, uint64_t uevent_seqnum_not_before, usec_t timestamp_not_before, DissectImageFlags flags, DissectedImage **ret); -int dissect_image_and_warn(int fd, const char *name, const VeritySettings *verity, const MountOptions *mount_options, uint64_t uevent_seqnum_not_before, usec_t timestamp_not_before, DissectImageFlags flags, DissectedImage **ret); +int dissect_image(int fd, const VeritySettings *verity, const MountOptions *mount_options, uint64_t diskseq, uint64_t uevent_seqnum_not_before, usec_t timestamp_not_before, DissectImageFlags flags, DissectedImage **ret); +int dissect_image_and_warn(int fd, const char *name, const VeritySettings *verity, const MountOptions *mount_options, uint64_t diskseq, uint64_t uevent_seqnum_not_before, usec_t timestamp_not_before, DissectImageFlags flags, DissectedImage **ret); DissectedImage* dissected_image_unref(DissectedImage *m); DEFINE_TRIVIAL_CLEANUP_FUNC(DissectedImage*, dissected_image_unref); diff --git a/src/sysext/sysext.c b/src/sysext/sysext.c index 572e4007fe2..0d1f1c5218a 100644 --- a/src/sysext/sysext.c +++ b/src/sysext/sysext.c @@ -532,6 +532,7 @@ static int merge_subprocess(Hashmap *images, const char *workspace) { img->path, &verity_settings, NULL, + d->diskseq, d->uevent_seqnum_not_before, d->timestamp_not_before, flags, diff --git a/src/test/test-loop-block.c b/src/test/test-loop-block.c index 57f3279b676..1642f82e40d 100644 --- a/src/test/test-loop-block.c +++ b/src/test/test-loop-block.c @@ -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);