Merge pull request ceph#55234 from ajarr/wip-64063

rbd-nbd: use netlink interface by default

Reviewed-by: Ilya Dryomov <[email protected]>

Author: idryomov

PendingReleaseNotes

@@ -110,6 +110,9 @@ CephFS: Disallow delegating preallocated inode ranges to clients. Config
   and valid), diff-iterate is now guaranteed to execute locally if exclusive
   lock is available.  This brings a dramatic performance improvement for QEMU
   live disk synchronization and backup use cases.
+* RBD: The ``try-netlink`` mapping option for rbd-nbd has become the default
+  and is now deprecated. If the NBD netlink interface is not supported by the
+  kernel, then the mapping is retried using the legacy ioctl interface.
 
 >=18.0.0
 

qa/workunits/rbd/rbd-nbd.sh

@@ -205,6 +205,7 @@ used=`rbd -p ${POOL} --format xml du ${IMAGE} |
 unmap_device ${DEV} ${PID}
 
 # resize test
+# also test that try-netlink option is accepted for compatibility
 DEV=`_sudo rbd device -t nbd -o try-netlink map ${POOL}/${IMAGE}`
 get_pid ${POOL}
 devname=$(basename ${DEV})
@@ -391,7 +392,7 @@ cat ${LOG_FILE}
 expect_false grep 'quiesce failed' ${LOG_FILE}
 
 # test detach/attach
-OUT=`_sudo rbd device --device-type nbd --options try-netlink,show-cookie map ${POOL}/${IMAGE}`
+OUT=`_sudo rbd device --device-type nbd --show-cookie map ${POOL}/${IMAGE}`
 read DEV COOKIE <<< "${OUT}"
 get_pid ${POOL}
 _sudo mount ${DEV} ${TEMPDIR}/mnt
@@ -419,7 +420,7 @@ _sudo umount ${TEMPDIR}/mnt
 unmap_device ${DEV} ${PID}
 # if kernel supports cookies
 if [ -n "${COOKIE}" ]; then
-    OUT=`_sudo rbd device --device-type nbd --show-cookie --cookie "abc de" --options try-netlink map ${POOL}/${IMAGE}`
+    OUT=`_sudo rbd device --device-type nbd --show-cookie --cookie "abc de" map ${POOL}/${IMAGE}`
     read DEV ANOTHER_COOKIE <<< "${OUT}"
     get_pid ${POOL}
     test "${ANOTHER_COOKIE}" = "abc de"
@@ -429,7 +430,7 @@ DEV=
 
 # test detach/attach with --snap-id
 SNAPID=`rbd snap ls ${POOL}/${IMAGE} | awk '$2 == "snap" {print $1}'`
-OUT=`_sudo rbd device --device-type nbd --options try-netlink,show-cookie map --snap-id ${SNAPID} ${POOL}/${IMAGE}`
+OUT=`_sudo rbd device --device-type nbd --show-cookie map --snap-id ${SNAPID} ${POOL}/${IMAGE}`
 read DEV COOKIE <<< "${OUT}"
 get_pid ${POOL}
 _sudo rbd device detach ${POOL}/${IMAGE} --snap-id ${SNAPID} --device-type nbd

src/tools/rbd_nbd/rbd-nbd.cc

@@ -106,7 +106,6 @@ struct Config {
   bool quiesce = false;
   bool readonly = false;
   bool set_max_part = false;
-  bool try_netlink = false;
   bool show_cookie = false;
 
   std::string poolname;
@@ -166,7 +165,6 @@ static void usage()
             << "  --read-only                   Map read-only\n"
             << "  --reattach-timeout <sec>      Set nbd re-attach timeout\n"
             << "                                (default: " << Config().reattach_timeout << ")\n"
-            << "  --try-netlink                 Use the nbd netlink interface\n"
             << "  --show-cookie                 Show device cookie\n"
             << "  --cookie                      Specify device cookie\n"
             << "  --snap-id <snap-id>           Specify snapshot by ID instead of by name\n"
@@ -1682,7 +1680,7 @@ static int do_map(int argc, const char *argv[], Config *cfg, bool reconnect)
   unsigned long flags;
   unsigned long size;
   unsigned long blksize = RBD_NBD_BLKSIZE;
-  bool use_netlink;
+  bool use_netlink = true;
 
   int fd[2];
 
@@ -1859,20 +1857,17 @@ static int do_map(int argc, const char *argv[], Config *cfg, bool reconnect)
 
   server = start_server(fd[1], image, cfg);
 
-  use_netlink = cfg->try_netlink || reconnect;
-  if (use_netlink) {
-    // generate when the cookie is not supplied at CLI
-    if (!reconnect && cfg->cookie.empty()) {
-      uuid_d uuid_gen;
-      uuid_gen.generate_random();
-      cfg->cookie = uuid_gen.to_string();
-    }
-    r = try_netlink_setup(cfg, fd[0], size, flags, reconnect);
-    if (r < 0) {
-      goto free_server;
-    } else if (r == 1) {
-      use_netlink = false;
-    }
+  // generate when the cookie is not supplied at CLI
+  if (!reconnect && cfg->cookie.empty()) {
+    uuid_d uuid_gen;
+    uuid_gen.generate_random();
+    cfg->cookie = uuid_gen.to_string();
+  }
+  r = try_netlink_setup(cfg, fd[0], size, flags, reconnect);
+  if (r < 0) {
+    goto free_server;
+  } else if (r == 1) {
+    use_netlink = false;
   }
 
   if (!use_netlink) {
@@ -2216,7 +2211,8 @@ static int parse_args(vector<const char*>& args, std::ostream *err_msg,
     } else if (ceph_argparse_flag(args, i, "--pretty-format", (char *)NULL)) {
       cfg->pretty_format = true;
     } else if (ceph_argparse_flag(args, i, "--try-netlink", (char *)NULL)) {
-      cfg->try_netlink = true;
+      // netlink used by default. option not required anymore.
+      // accept for compatibility.
     } else if (ceph_argparse_flag(args, i, "--show-cookie", (char *)NULL)) {
       cfg->show_cookie = true;
     } else if (ceph_argparse_witharg(args, i, &cfg->cookie, "--cookie", (char *)NULL)) {