search for: next_get_size

...filter_close (struct backend *b, struct connection *conn) * single ‘void *nxdata’ struct pointer (‘b_conn’). */ +static int +next_reopen (void *nxdata, int readonly) +{ + struct b_conn *b_conn = nxdata; + return backend_reopen (b_conn->b, b_conn->conn, readonly); +} + static int64_t next_get_size (void *nxdata) { @@ -373,6 +380,7 @@ next_cache (void *nxdata, uint32_t count, uint64_t offset, } static struct nbdkit_next_ops next_ops = { + .reopen = next_reopen, .get_size = next_get_size, .can_write = next_can_write, .can_flush = next_can_flush, diff --git a/server/internal.h b/...

...filter_close (struct backend *b, struct connection *conn) * single ‘void *nxdata’ struct pointer (‘b_conn’). */ +static int +next_reopen (void *nxdata, int readonly) +{ + struct b_conn *b_conn = nxdata; + return backend_reopen (b_conn->b, b_conn->conn, readonly); +} + static int64_t next_get_size (void *nxdata) { @@ -373,6 +380,7 @@ next_cache (void *nxdata, uint32_t count, uint64_t offset, } static struct nbdkit_next_ops next_ops = { + .reopen = next_reopen, .get_size = next_get_size, .can_write = next_can_write, .can_flush = next_can_flush, diff --git a/server/internal.h b/...

...* pointer, backend_* functions expect a struct backend * parameter). - * nxdata is a pointer to the next backend in the linked list. - */ - -static int -next_reopen (void *nxdata, int readonly) -{ - struct backend *b_next = nxdata; - return backend_reopen (b_next, readonly); -} - -static int64_t -next_get_size (void *nxdata) -{ - struct backend *b_next = nxdata; - return backend_get_size (b_next); -} - -static int -next_can_write (void *nxdata) -{ - struct backend *b_next = nxdata; - return backend_can_write (b_next); -} - -static int -next_can_flush (void *nxdata) -{ - struct backend *b_next = nxda...

...k the two parameters from a + * single ‘void *nxdata’ struct pointer (‘b_conn’). + */ + +/* Literally a backend + a connection pointer. This is the + * implementation if ‘void *nxdata’ in the filter API. + */ +struct b_conn { + struct backend *b; + struct connection *conn; +}; + +static int64_t +next_get_size (void *nxdata) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->get_size (b_conn->b, b_conn->conn); +} + +static int +next_can_write (void *nxdata) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->can_write (b_conn->b, b_conn->conn); +} + +static int +nex...

This is a retry filter implementation as outlined here: https://www.redhat.com/archives/libguestfs/2019-September/msg00167.html It is only lightly tested. One way to test it is to try an SSH copy (see the commit message for patch 2/2), and in the middle of the copy kill the per-connection sshd on the remote machine. You will see that the copy recovers after a few seconds. Add the nbdkit -v

v1 was here: https://www.redhat.com/archives/libguestfs/2019-September/msg00199.html v2: - Adds a fairly simple yet comprehensive test using sh plugin. - Rebase and retest. Patch 1 is a misc patch not really related to the series. Rich.

...t nbdkit_extent **extents, + int *err) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->extents (b_conn->b, b_conn->conn, count, offset, flags, + nr_extents, extents, err); +} + static struct nbdkit_next_ops next_ops = { .get_size = next_get_size, .can_write = next_can_write, @@ -371,6 +388,7 @@ static struct nbdkit_next_ops next_ops = { .is_rotational = next_is_rotational, .can_trim = next_can_trim, .can_zero = next_can_zero, + .can_extents = next_can_extents, .can_fua = next_can_fua, .can_multi_conn = next_can_multi_con...

...ta is a pointer to the next backend in the linked list. */ static int next_reopen (void *nxdata, int readonly) { - struct b_h *b_h = nxdata; - return backend_reopen (b_h->b, readonly); + struct backend *b_next = nxdata; + return backend_reopen (b_next, readonly); } static int64_t next_get_size (void *nxdata) { - struct b_h *b_h = nxdata; - return backend_get_size (b_h->b); + struct backend *b_next = nxdata; + return backend_get_size (b_next); } static int next_can_write (void *nxdata) { - struct b_h *b_h = nxdata; - return backend_can_write (b_h->b); + struct backend...

v2 was here: https://www.redhat.com/archives/libguestfs/2019-September/msg00221.html I think this is more like "the one". It handles reopen failing correctly, and there is a second test for that. I also ran my sshd tests locally and it worked in all scenarios I could think up (except of course sshd not being available at the start, but we want that to fail). Rich.

...t nbdkit_extents_map *extents_map, + int *err) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->extents (b_conn->b, b_conn->conn, count, offset, flags, + extents_map, err); +} + static struct nbdkit_next_ops next_ops = { .get_size = next_get_size, .can_write = next_can_write, @@ -371,6 +388,7 @@ static struct nbdkit_next_ops next_ops = { .is_rotational = next_is_rotational, .can_trim = next_can_trim, .can_zero = next_can_zero, + .can_extents = next_can_extents, .can_fua = next_can_fua, .can_multi_conn = next_can_multi_con...

...t nbdkit_extents_map *extents_map, + int *err) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->extents (b_conn->b, b_conn->conn, count, offset, flags, + extents_map, err); +} + static struct nbdkit_next_ops next_ops = { .get_size = next_get_size, .can_write = next_can_write, @@ -371,6 +388,7 @@ static struct nbdkit_next_ops next_ops = { .is_rotational = next_is_rotational, .can_trim = next_can_trim, .can_zero = next_can_zero, + .can_extents = next_can_extents, .can_fua = next_can_fua, .can_multi_conn = next_can_multi_con...

...flags, + struct nbdkit_extents *extents, int *err) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->extents (b_conn->b, b_conn->conn, count, offset, flags, + extents, err); +} + static struct nbdkit_next_ops next_ops = { .get_size = next_get_size, .can_write = next_can_write, @@ -371,6 +387,7 @@ static struct nbdkit_next_ops next_ops = { .is_rotational = next_is_rotational, .can_trim = next_can_trim, .can_zero = next_can_zero, + .can_extents = next_can_extents, .can_fua = next_can_fua, .can_multi_conn = next_can_multi_con...

This tentative commit implements extents/can_extents, roughly as discussed in the previous thread here: https://www.redhat.com/archives/libguestfs/2019-March/msg00017.html I can't say that I'm a big fan of having the plugin allocate an extents array. There are no other plugin callbacks currently where we require the plugin to allocate complex data structures (or indeed do any allocation

...flags, + struct nbdkit_extents *extents, int *err) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->extents (b_conn->b, b_conn->conn, count, offset, flags, + extents, err); +} + static struct nbdkit_next_ops next_ops = { .get_size = next_get_size, .can_write = next_can_write, @@ -371,6 +387,7 @@ static struct nbdkit_next_ops next_ops = { .is_rotational = next_is_rotational, .can_trim = next_can_trim, .can_zero = next_can_zero, + .can_extents = next_can_extents, .can_fua = next_can_fua, .can_multi_conn = next_can_multi_con...

I'm not sure which version we're up to now. Anyway I believe this addresses all the points that Eric raised in: https://www.redhat.com/archives/libguestfs/2019-March/msg00038.html https://www.redhat.com/archives/libguestfs/2019-March/msg00040.html In particular: - default state of extents_map is all allocated disk - support hole + non-zero - you can now iterate with bounds -

...flags, + struct nbdkit_extents *extents, int *err) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->extents (b_conn->b, b_conn->conn, count, offset, flags, + extents, err); +} + static struct nbdkit_next_ops next_ops = { .get_size = next_get_size, .can_write = next_can_write, @@ -371,6 +387,7 @@ static struct nbdkit_next_ops next_ops = { .is_rotational = next_is_rotational, .can_trim = next_can_trim, .can_zero = next_can_zero, + .can_extents = next_can_extents, .can_fua = next_can_fua, .can_multi_conn = next_can_multi_con...

...k the two parameters from a + * single ‘void *nxdata’ struct pointer (‘b_conn’). + */ + +/* Literally a backend + a connection pointer. This is the + * implementation of ‘void *nxdata’ in the filter API. + */ +struct b_conn { + struct backend *b; + struct connection *conn; +}; + +static int64_t +next_get_size (void *nxdata) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->get_size (b_conn->b, b_conn->conn); +} + +static int +next_can_write (void *nxdata) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->can_write (b_conn->b, b_conn->conn); +} + +static int +nex...

...ters to backend + * functions. However because these functions are all expecting a + * backend and a connection, we cannot call them directly, but must + * write some next_* functions that unpack the two parameters from a + * single ‘void *nxdata’ struct pointer (‘b_conn’). + */ + +static int64_t +next_get_size (void *nxdata) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->get_size (b_conn->b, b_conn->conn); +} + +static int +next_can_write (void *nxdata) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->can_write (b_conn->b, b_conn->conn); +} + +static int +nex...

Second version based on nbdkit_extent* calls, as discussed here: https://www.redhat.com/archives/libguestfs/2019-March/msg00033.html Note in particular there is some subtlety about how filters would work in this implementation. See docs/nbdkit-filter.pod for the details. Rich.

...t nbdkit_extents_map *extents_map, + int *err) +{ + struct b_conn *b_conn = nxdata; + return b_conn->b->extents (b_conn->b, b_conn->conn, count, offset, flags, + extents_map, err); +} + static struct nbdkit_next_ops next_ops = { .get_size = next_get_size, .can_write = next_can_write, @@ -371,6 +388,7 @@ static struct nbdkit_next_ops next_ops = { .is_rotational = next_is_rotational, .can_trim = next_can_trim, .can_zero = next_can_zero, + .can_extents = next_can_extents, .can_fua = next_can_fua, .can_multi_conn = next_can_multi_con...