search for: flush_after_command

...h) (void *op, void *handle); int (*trim) (void *op, void *handle, uint32_t count, uint64_t offset); int (*zero) (void *op, void *handle, uint32_t count, uint64_t offset, int may_trim); }; // Called by the lowlevel api to send a reply to the client void nbdkit_reply(void *vop) { int r; bool flush_after_command; struct operation *op = (struct operation *) vop; flush_after_command = (op->flags & NBD_CMD_FLAG_FUA) != 0; if (!op->conn->can_flush || op->conn->readonly) flush_after_command = false; if (flush_after_command) { op->flags = 0; // clear flags r = plugin_f...

Tested via: term1$ qemu-nbd -k $PWD/sock -t -f raw -x foo junk --trace=nbd_\* term2$ ./nbdkit -f -v -e bar nbd socket=$PWD/sock export=foo term3$ qemu-io -t none -f raw nbd://localhost:10809/bar --trace=nbd_\* and checking the traces to see that 'w 0 1' vs. 'w -f 0 1' was able to influence whether the FUA flag showed up at the server in term1. Still to go: figure out how to

----- Forwarded message ----- Date: Sat, 18 Feb 2017 22:21:19 -0500 Subject: nbdkit async Hello, Hope this is the right person to contact regarding nbdkit design. I have a high latency massively parallel device that I am currently implementing as an nbdkit plugin in c++ and have run into some design limitations due to the synchronous callback interface nbdkit requires. Nbdkit is currently

...no is not + * On read/write errors, sets *error to the value stored in + * nbdkit_set_error(), falling back to errno (or EIO if errno is not * set) and returns 0. */ static int @@ -628,11 +642,15 @@ _handle_request (struct connection *conn, if (!conn->can_flush || conn->readonly) flush_after_command = false; + /* The plugin should call nbdkit_set_error() to request a particular + error, otherwise we fallback to errno or EIO. */ + tls_set_error (0); + switch (cmd) { case NBD_CMD_READ: r = plugin_pread (conn, buf, count, offset); if (r == -1) { - *error = errno ? errn...

...gs & NBD_CMD_FLAG_NO_HOLE)) == -1) + if (backend->zero (backend, conn, count, offset, + !(flags & NBD_CMD_FLAG_NO_HOLE)) == -1) return get_error (conn); break; @@ -910,7 +912,7 @@ handle_request (struct connection *conn, abort (); } - if (flush_after_command && plugin_flush (conn) == -1) + if (flush_after_command && backend->flush (backend, conn) == -1) return get_error (conn); return 0; diff --git a/src/internal.h b/src/internal.h index 068204b..d0c60f2 100644 --- a/src/internal.h +++ b/src/internal.h @@ -108,6 +108,8 @@...

...gs & NBD_CMD_FLAG_NO_HOLE)) == -1) + if (backend->zero (backend, conn, count, offset, + !(flags & NBD_CMD_FLAG_NO_HOLE)) == -1) return get_error (conn); break; @@ -910,7 +912,7 @@ handle_request (struct connection *conn, abort (); } - if (flush_after_command && plugin_flush (conn) == -1) + if (flush_after_command && backend->flush (backend, conn) == -1) return get_error (conn); return 0; diff --git a/src/internal.h b/src/internal.h index 068204b..9c4993d 100644 --- a/src/internal.h +++ b/src/internal.h @@ -35,6 +35,7 @@ #...

...gs & NBD_CMD_FLAG_NO_HOLE)) == -1) + if (backend->zero (backend, conn, count, offset, + !(flags & NBD_CMD_FLAG_NO_HOLE)) == -1) return get_error (conn); break; @@ -910,7 +912,7 @@ handle_request (struct connection *conn, abort (); } - if (flush_after_command && plugin_flush (conn) == -1) + if (flush_after_command && backend->flush (backend, conn) == -1) return get_error (conn); return 0; diff --git a/src/internal.h b/src/internal.h index 068204b..9c4993d 100644 --- a/src/internal.h +++ b/src/internal.h @@ -35,6 +35,7 @@ #...

A combination of the work that both Rich and I have been doing lately, where filters use only the new API with flags on every command that the client can send over the wire (we can then add support for more flags in nbdkit without having to add new callbacks, as NBD adds more flags upstream). Eric Blake (4): protocol: Split flags from cmd field in requests backend: Pass flags argument through

I want to make my nbd forwarding plugin fully parallel - but to do that, I first need to make nbdkit itself fully parallel ;) With this series, I was finally able to demonstrate out-of-order responses when using qemu-io (which is great at sending back-to-back requests prior to waiting for responses) coupled with the nbd file plugin (which has a great feature of rdelay and wdelay, to make it

Fix some things I noticed while reviewing v1, and follow Rich's idea to add a new nbdkit_set_error() utility function with a binding for Python users to request a particular error (rather than being forced to live with whatever stale value is in errno after all the intermediate binding glue code). I could not easily find out how to register a C function callable from perl bindings, and have

...NBD_CMD_WRITE_ZEROES: r = plugin_zero (conn, count, offset, !(flags & NBD_CMD_FLAG_NO_HOLE)); if (r == -1) { - *error = errno ? errno : EIO; + *error = get_error (conn); return 0; } break; @@ -676,7 +690,7 @@ _handle_request (struct connection *conn, if (flush_after_command) { r = plugin_flush (conn); if (r == -1) { - *error = errno ? errno : EIO; + *error = get_error (conn); return 0; } } diff --git a/src/internal.h b/src/internal.h index 4632f51..2129337 100644 --- a/src/internal.h +++ b/src/internal.h @@ -120,6 +120,7 @@ struct co...

This cleans up the existing code base with regards to implicit use of errno from language bindings, then rebases the previous work in python on top of that. I'm still playing with the perl bindings, but got further after reading 'perldoc perlembed'. Eric Blake (4): plugins: Don't use bogus errno from non-C plugins plugins: Add new nbdkit_set_error() utility function python:

v1 -> v2: - Fixed everything mentioned in the review. Rich.

Somewhat invasive but mostly mechanical change to how plugins are called. This patch is in preparation for adding a second backend subtype for filters. Rich.

The first three patches are identical to: https://www.redhat.com/archives/libguestfs/2018-January/msg00079.html "[PATCH nbdkit v2 0/3] Refactor plugin_* functions into a backend" The rest of the patches add filters using the new filter API previously described here: https://www.redhat.com/archives/libguestfs/2018-January/msg00073.html This needs a lot more testing -- and tests --