* [PATCH v2 2/2] qemu-nbd: Removed deprecated --partition option
2020-01-23 16:46 [PATCH v2 0/2] finish qemu-nbd --partition deprecation Eric Blake
2020-01-23 16:46 ` [PATCH v2 1/2] docs: Fix typo in qemu-nbd -P replacement Eric Blake
@ 2020-01-23 16:46 ` Eric Blake
2020-02-05 22:28 ` Ján Tomko
2020-01-31 17:11 ` [PATCH v2 0/2] finish qemu-nbd --partition deprecation Eric Blake
2 siblings, 1 reply; 8+ messages in thread
From: Eric Blake @ 2020-01-23 16:46 UTC (permalink / raw)
To: qemu-devel
Cc: reviewer:Incompatible changes, peter.maydell,
open list:Network Block Dev..., mreitz
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 <eblake@redhat.com>
---
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 873bb9e17d56..2e20f84cf025 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 358eb6deebdc..f152e8816164 100644
--- a/qemu-deprecated.texi
+++ b/qemu-deprecated.texi
@@ -319,37 +319,6 @@ 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
@@ -406,3 +375,21 @@ 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 108a51f7eb01..a04930770ff7 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;
@@ -793,15 +700,6 @@ 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;
@@ -898,7 +796,7 @@ 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");
@@ -1162,33 +1060,6 @@ 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,
--
2.24.1
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