From 0bc16997f5404134637227e53b637d0825d46b5a Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Thu, 23 Jan 2020 10:46:50 -0600 Subject: qemu-nbd: Removed deprecated --partition option The option was deprecated in 4.0.0 (commit 0ae2d546); it's now been long enough with no complaints to follow through with that process. Signed-off-by: Eric Blake Message-Id: <20200123164650.1741798-3-eblake@redhat.com> Reviewed-by: Ján Tomko --- docs/interop/qemu-nbd.rst | 15 ++---- qemu-deprecated.texi | 49 +++++++---------- qemu-nbd.c | 133 +--------------------------------------------- 3 files changed, 24 insertions(+), 173 deletions(-) diff --git a/docs/interop/qemu-nbd.rst b/docs/interop/qemu-nbd.rst index df7b6b9d0d..e548403100 100644 --- a/docs/interop/qemu-nbd.rst +++ b/docs/interop/qemu-nbd.rst @@ -72,13 +72,6 @@ driver options if ``--image-opts`` is specified. Export the disk as read-only. -.. option:: -P, --partition=NUM - - Deprecated: Only expose MBR partition *NUM*. Understands physical - partitions 1-4 and logical partition 5. New code should instead use - :option:`--image-opts` with the raw driver wrapping a subset of the - original image. - .. option:: -B, --bitmap=NAME If *filename* has a qcow2 persistent bitmap *NAME*, expose @@ -224,14 +217,14 @@ a 1 megabyte subset of a raw file, using the export name 'subset': -t -x subset -p 10810 \ --image-opts driver=raw,offset=1M,size=1M,file.driver=file,file.filename=file.raw -Serve a read-only copy of just the first MBR partition of a guest -image over a Unix socket with as many as 5 simultaneous readers, with -a persistent process forked as a daemon: +Serve a read-only copy of a guest image over a Unix socket with as +many as 5 simultaneous readers, with a persistent process forked as a +daemon: :: qemu-nbd --fork --persistent --shared=5 --socket=/path/to/sock \ - --partition=1 --read-only --format=qcow2 file.qcow2 + --read-only --format=qcow2 file.qcow2 Expose the guest-visible contents of a qcow2 file via a block device /dev/nbd0 (and possibly creating /dev/nbd0p1 and friends for diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi index c8ee68a466..2634e00ec8 100644 --- a/qemu-deprecated.texi +++ b/qemu-deprecated.texi @@ -313,37 +313,6 @@ The above, converted to the current supported format: @section Related binaries -@subsection qemu-nbd --partition (since 4.0.0) - -The ``qemu-nbd --partition $digit'' code (also spelled @option{-P}) -can only handle MBR partitions, and has never correctly handled -logical partitions beyond partition 5. If you know the offset and -length of the partition (perhaps by using @code{sfdisk} within the -guest), you can achieve the effect of exporting just that subset of -the disk by use of the @option{--image-opts} option with a raw -blockdev using the @code{offset} and @code{size} parameters layered on -top of any other existing blockdev. For example, if partition 1 is -100MiB long starting at 1MiB, the old command: - -@code{qemu-nbd -t -P 1 -f qcow2 file.qcow2} - -can be rewritten as: - -@code{qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.file.driver=file,file.file.filename=file.qcow2} - -Alternatively, the @code{nbdkit} project provides a more powerful -partition filter on top of its nbd plugin, which can be used to select -an arbitrary MBR or GPT partition on top of any other full-image NBD -export. Using this to rewrite the above example results in: - -@code{qemu-nbd -t -k /tmp/sock -f qcow2 file.qcow2 &} -@code{nbdkit -f --filter=partition nbd socket=/tmp/sock partition=1} - -Note that if you are exposing the export via /dev/nbd0, it is easier -to just export the entire image and then mount only /dev/nbd0p1 than -it is to reinvoke @command{qemu-nbd -c /dev/nbd0} limited to just a -subset of the image. - @subsection qemu-img convert -n -o (since 4.2.0) All options specified in @option{-o} are image creation options, so @@ -400,3 +369,21 @@ trouble after a recent upgrade. The "autoload" parameter has been ignored since 2.12.0. All bitmaps are automatically loaded from qcow2 images. + +@section Related binaries + +@subsection qemu-nbd --partition (removed in 5.0.0) + +The ``qemu-nbd --partition $digit'' code (also spelled @option{-P}) +could only handle MBR partitions, and never correctly handled logical +partitions beyond partition 5. Exporting a partition can still be +done by utilizing the @option{--image-opts} option with a raw blockdev +using the @code{offset} and @code{size} parameters layered on top of +any other existing blockdev. For example, if partition 1 is 100MiB +long starting at 1MiB, the old command: + +@code{qemu-nbd -t -P 1 -f qcow2 file.qcow2} + +can be rewritten as: + +@code{qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.file.driver=file,file.file.filename=file.qcow2} diff --git a/qemu-nbd.c b/qemu-nbd.c index db29a0d0ed..4aa005004e 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -100,7 +100,6 @@ static void usage(const char *name) "\n" "Exposing part of the image:\n" " -o, --offset=OFFSET offset into the image\n" -" -P, --partition=NUM only expose partition NUM\n" " -B, --bitmap=NAME expose a persistent dirty bitmap\n" "\n" "General purpose options:\n" @@ -156,96 +155,6 @@ QEMU_COPYRIGHT "\n" , name); } -struct partition_record -{ - uint8_t bootable; - uint8_t start_head; - uint32_t start_cylinder; - uint8_t start_sector; - uint8_t system; - uint8_t end_head; - uint8_t end_cylinder; - uint8_t end_sector; - uint32_t start_sector_abs; - uint32_t nb_sectors_abs; -}; - -static void read_partition(uint8_t *p, struct partition_record *r) -{ - r->bootable = p[0]; - r->start_head = p[1]; - r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300); - r->start_sector = p[2] & 0x3f; - r->system = p[4]; - r->end_head = p[5]; - r->end_cylinder = p[7] | ((p[6] << 2) & 0x300); - r->end_sector = p[6] & 0x3f; - - r->start_sector_abs = ldl_le_p(p + 8); - r->nb_sectors_abs = ldl_le_p(p + 12); -} - -static int find_partition(BlockBackend *blk, int partition, - uint64_t *offset, uint64_t *size) -{ - struct partition_record mbr[4]; - uint8_t data[MBR_SIZE]; - int i; - int ext_partnum = 4; - int ret; - - ret = blk_pread(blk, 0, data, sizeof(data)); - if (ret < 0) { - error_report("error while reading: %s", strerror(-ret)); - exit(EXIT_FAILURE); - } - - if (data[510] != 0x55 || data[511] != 0xaa) { - return -EINVAL; - } - - for (i = 0; i < 4; i++) { - read_partition(&data[446 + 16 * i], &mbr[i]); - - if (!mbr[i].system || !mbr[i].nb_sectors_abs) { - continue; - } - - if (mbr[i].system == 0xF || mbr[i].system == 0x5) { - struct partition_record ext[4]; - uint8_t data1[MBR_SIZE]; - int j; - - ret = blk_pread(blk, mbr[i].start_sector_abs * MBR_SIZE, - data1, sizeof(data1)); - if (ret < 0) { - error_report("error while reading: %s", strerror(-ret)); - exit(EXIT_FAILURE); - } - - for (j = 0; j < 4; j++) { - read_partition(&data1[446 + 16 * j], &ext[j]); - if (!ext[j].system || !ext[j].nb_sectors_abs) { - continue; - } - - if ((ext_partnum + j + 1) == partition) { - *offset = (uint64_t)ext[j].start_sector_abs << 9; - *size = (uint64_t)ext[j].nb_sectors_abs << 9; - return 0; - } - } - ext_partnum += 4; - } else if ((i + 1) == partition) { - *offset = (uint64_t)mbr[i].start_sector_abs << 9; - *size = (uint64_t)mbr[i].nb_sectors_abs << 9; - return 0; - } - } - - return -ENOENT; -} - static void termsig_handler(int signum) { atomic_cmpxchg(&state, RUNNING, TERMINATE); @@ -617,7 +526,7 @@ int main(int argc, char **argv) int64_t fd_size; QemuOpts *sn_opts = NULL; const char *sn_id_or_name = NULL; - const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:B:L"; + const char *sopt = "hVb:o:p:rsnc:dvk:e:f:tl:x:T:D:B:L"; struct option lopt[] = { { "help", no_argument, NULL, 'h' }, { "version", no_argument, NULL, 'V' }, @@ -626,7 +535,6 @@ int main(int argc, char **argv) { "socket", required_argument, NULL, 'k' }, { "offset", required_argument, NULL, 'o' }, { "read-only", no_argument, NULL, 'r' }, - { "partition", required_argument, NULL, 'P' }, { "bitmap", required_argument, NULL, 'B' }, { "connect", required_argument, NULL, 'c' }, { "disconnect", no_argument, NULL, 'd' }, @@ -657,7 +565,6 @@ int main(int argc, char **argv) int ch; int opt_ind = 0; int flags = BDRV_O_RDWR; - int partition = 0; int ret = 0; bool seen_cache = false; bool seen_discard = false; @@ -789,15 +696,6 @@ int main(int argc, char **argv) readonly = true; flags &= ~BDRV_O_RDWR; break; - case 'P': - warn_report("The '-P' option is deprecated; use --image-opts with " - "a raw device wrapper for subset exports instead"); - if (qemu_strtoi(optarg, NULL, 0, &partition) < 0 || - partition < 1 || partition > 8) { - error_report("Invalid partition '%s'", optarg); - exit(EXIT_FAILURE); - } - break; case 'B': bitmap = optarg; break; @@ -894,7 +792,7 @@ int main(int argc, char **argv) error_report("List mode is incompatible with a file name"); exit(EXIT_FAILURE); } - if (export_name || export_description || dev_offset || partition || + if (export_name || export_description || dev_offset || device || disconnect || fmt || sn_id_or_name || bitmap || seen_aio || seen_discard || seen_cache) { error_report("List mode is incompatible with per-device settings"); @@ -1158,33 +1056,6 @@ int main(int argc, char **argv) } fd_size -= dev_offset; - if (partition) { - uint64_t limit; - - if (dev_offset) { - error_report("Cannot request partition and offset together"); - exit(EXIT_FAILURE); - } - ret = find_partition(blk, partition, &dev_offset, &limit); - if (ret < 0) { - error_report("Could not find partition %d: %s", partition, - strerror(-ret)); - exit(EXIT_FAILURE); - } - /* - * MBR partition limits are (32-bit << 9); this assert lets - * the compiler know that we can't overflow 64 bits. - */ - assert(dev_offset + limit >= dev_offset); - if (dev_offset + limit > fd_size) { - error_report("Discovered partition %d at offset %" PRIu64 - " size %" PRIu64 ", but size exceeds file length %" - PRId64, partition, dev_offset, limit, fd_size); - exit(EXIT_FAILURE); - } - fd_size = limit; - } - export = nbd_export_new(bs, dev_offset, fd_size, export_name, export_description, bitmap, readonly, shared > 1, nbd_export_closed, writethrough, NULL, -- cgit v1.2.3-55-g7522