search for: nbd_read_on

...bnbd.pod b/docs/libnbd.pod index 74227fd..6a329d6 100644 --- a/docs/libnbd.pod +++ b/docs/libnbd.pod @@ -383,7 +383,7 @@ the export, such as whether it is writable and if it can support flush to permanent storage. These flags can be accessed from libnbd using APIs such as: - int is_read_only = nbd_read_only (nbd); + int is_read_only = nbd_is_read_only (nbd); int can_flush = nbd_can_flush (nbd); (and several more, see L<libnbd-api(3)>). diff --git a/examples/batched-read-write.c b/examples/batched-read-write.c index 9d2c02b..d39a1e5 100644 --- a/examples/batched-read-write.c +++ b/examples...

...ck to support both versions. diff --git i/plugins/nbd/nbd.c w/plugins/nbd/nbd.c index f11e54d5..a83ded5e 100644 --- i/plugins/nbd/nbd.c +++ w/plugins/nbd/nbd.c @@ -566,11 +566,15 @@ nbdplug_get_size (void *handle) return size; } +#ifndef LIBNBD_HAVE_NBD_IS_READ_ONLY +# define nbd_is_read_only nbd_read_only +#endif + static int nbdplug_can_write (void *handle) { struct handle *h = handle; - int i = nbd_read_only (h->nbd); + int i = nbd_is_read_only (h->nbd); if (i == -1) { nbdkit_error ("failure to check readonly flag: %s", nbd_get_error ()); -- Eric Blake, Princi...

One API change, some small documentation changes.

The 0.9.8 release breaks API, requiring a number of changes: - Use symbolic constants instead of magic numbers/open-coded strings (well, the string for "base:allocation" was present before this libnbd bump) - Change callbacks to drop the valid_flag parameter - Add _is to nbd_read_only call - Drop the _callback suffix on nbd_aio_FOO calls - Add a struct for managing callback/user_data at once Signed-off-by: Eric Blake <eblake@redhat.com> --- Pushing, since we're releasing libnbd 0.9.8 today configure.ac | 4 +-- plugins/nbd/nbd.c | 85 +++++++++++++++++++++--...

...9,7 +189,6 @@ start_thread (void *arg) size_t i; uint64_t offset, handle; uint64_t handles[MAX_IN_FLIGHT]; - size_t in_flight; /* counts number of requests in flight */ int dir, r, cmd; time_t t; bool expired = false; @@ -231,8 +230,8 @@ start_thread (void *arg) assert (nbd_read_only (nbd) == 0); /* Issue commands. */ - in_flight = 0; - while (!expired || in_flight > 0) { + assert (nbd_aio_in_flight (nbd) == 0); + while (!expired || nbd_aio_in_flight (nbd) > 0) { if (nbd_aio_is_dead (nbd) || nbd_aio_is_closed (nbd)) { fprintf (stderr, "thread %z...

...elease breaks API, requiring a number of changes: > - Use symbolic constants instead of magic numbers/open-coded strings > (well, the string for "base:allocation" was present before this > libnbd bump) > - Change callbacks to drop the valid_flag parameter > - Add _is to nbd_read_only call > - Drop the _callback suffix on nbd_aio_FOO calls > - Add a struct for managing callback/user_data at once Seems reasonable. > @@ -160,11 +160,12 @@ nbdplug_config (const char *key, const char *value) > if (strcasecmp (value, "require") == 0 || > str...

...d, argv[1]) == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + } + else { + if (nbd_connect_tcp (nbd, argv[1], argv[2]) == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + } + + if (nbd_read_only (nbd) == 1) { + fprintf (stderr, "%s: error: this NBD export is read-only\n", argv[0]); + exit (EXIT_FAILURE); + } + + exportsize = nbd_get_size (nbd); + if (exportsize == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + packets...

...d, argv[1]) == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + } + else { + if (nbd_connect_tcp (nbd, argv[1], argv[2]) == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + } + + if (nbd_read_only (nbd) == 1) { + fprintf (stderr, "%s: error: this NBD export is read-only\n", argv[0]); + exit (EXIT_FAILURE); + } + + exportsize = nbd_get_size (nbd); + if (exportsize == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + packets...

...p (nbd, argv[1], argv[2]) == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + } + + exportsize = nbd_get_size (nbd); + if (exportsize == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + + if (nbd_read_only (nbd) == 1) { + fprintf (stderr, "%s: error: this NBD export is read-only\n", argv[0]); + exit (EXIT_FAILURE); + } + +#if NR_MULTI_CONN > 1 + if (nbd_can_multi_conn (nbd) == 0) { + fprintf (stderr, "%s: error: " + "this NBD export does not suppor...

...p (nbd, argv[1], argv[2]) == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + } + + exportsize = nbd_get_size (nbd); + if (exportsize == -1) { + fprintf (stderr, "%s\n", nbd_get_error ()); + exit (EXIT_FAILURE); + } + + if (nbd_read_only (nbd) == 1) { + fprintf (stderr, "%s: error: this NBD export is read-only\n", argv[0]); + exit (EXIT_FAILURE); + } + + if (nbd_can_multi_conn (nbd) == 0) { + fprintf (stderr, "%s: error: " + "this NBD export does not support multi-conn\n", argv...

This might not be the final solution, but it certainly seems to solve a deadlock for me that I could trigger by using 'nbdkit --filter=noparallel memory 512k' and calling nbd_aio_pread for a request larger than 256k (enough for the Linux kernel to block the server until libnbd read()s), immediately followed by nbd_aio_pwrite for a request larger than 256k (enough to block libnbd until the

On v1, we discussed whether cmds_to_issue needed to be a list, since it never had more than one element. I played with the idea of making it a list, and allowing the client to queue up new commands regardless of whether the state machine is currently in READY. I also polished up the tmp demo into a bit more full-fledged example file, worth including since it also let me discover a hard-to-hit race

Since v2: - rebase to Rich's new API calls - more refactoring in patch 1 (retitled) - new patches 3 and 4 - fix data corruption in patch 6 (was 4) - more tweaks to the reproducer example (including using new API from 3) Eric Blake (7): lib: Refactor command_common() to do more common work commands: Allow for a command queue commands: Expose FIFO ordering of server completions

...ndle; + int64_t size = nbd_get_size (h->nbd); - return h->size; + if (size == -1) { + nbdkit_error ("failure to get size: %s", nbd_get_error ()); + return -1; + } + return size; } static int nbdplug_can_write (void *handle) { struct handle *h = handle; + int i = nbd_read_only (h->nbd); - return !(h->flags & NBD_FLAG_READ_ONLY); + if (i == -1) { + nbdkit_error ("failure to check readonly flag: %s", nbd_get_error ()); + return -1; + } + return !(i || h->readonly); } static int nbdplug_can_flush (void *handle) { struct handle *h...

...ndle; + int64_t size = nbd_get_size (h->nbd); - return h->size; + if (size == -1) { + nbdkit_error ("failure to get size: %s", nbd_get_error ()); + return -1; + } + return size; } static int nbdplug_can_write (void *handle) { struct handle *h = handle; + int i = nbd_read_only (h->nbd); - return !(h->flags & NBD_FLAG_READ_ONLY); + if (i == -1) { + nbdkit_error ("failure to check readonly flag: %s", nbd_get_error ()); + return -1; + } + return !(i || h->readonly); } static int nbdplug_can_flush (void *handle) { struct handle *h...

I still need to wire in the use of *_notify functions into nbdkit to prove whether it makes the code any faster or easier to maintain, but at least the added example shows one good use case for the new API. Eric Blake (6): api: Add nbd_aio_in_flight generator: Allow DEAD state actions to run generator: Allow Int64 in callbacks states: Prepare for aio notify callback api: Add new

This works, but there's no time saving and I'm still investigating whether it does what I think it does. Nevertheless I thought I would post it because it (probably) implements the idea I had last night outlined in: https://www.redhat.com/archives/libguestfs/2019-June/msg00010.html The meat of the change is patch 4. Patch 5 is an example which I would probably fold into patch 4 for

v1: https://www.redhat.com/archives/libguestfs/2019-June/msg00014.html I pushed a few bits which are uncontroversial. The main changes since v1 are: An extra patch removes the want_to_send / check for nbd_aio_is_ready in examples/threaded-reads-and-writes.c. This logic was wrong since commit 6af72b87 as was pointed out by Eric in his review. Comments and structure of

Patch 1 played with an early draft of Rich's Fedora 30 libnbd package: https://bugzilla.redhat.com/show_bug.cgi?id=1713767#c17 Note that comment 21 provides a newer package 0.1.1-1 with a different API; and that libnbd has more unreleased API changes in the pipeline (whether that will be called 0.2 or 0.1.2); so we'll have to tweak things based on what is actually available in distros.

libnbd-0.1.2-1 is now available in Fedora 29/30 updates-testing, although it was not compiled against libxml2 so it lacks uri support (I ended up testing patch 4 with a self-built libnbd). Diffs since v1 - rebase to master, bump from libnbd 0.1 to 0.1.2, add URI support, better timing results Still not done - patch 5 needs associated tests Eric Blake (5): nbd: Check for libnbd nbd: