similar to: [nbdkit PATCH] plugins: Add .can_zero callback

It may be useful to test whether the client's use of NBD_CMD_FLAG_NO_HOLE makes a difference; do this by adding a mode to --filter=nozero to force a non-trimming zero write. Signed-off-by: Eric Blake <eblake@redhat.com> --- filters/nozero/nbdkit-nozero-filter.pod | 19 +++++++---- filters/nozero/nozero.c | 45 ++++++++++++++++++++----- tests/test-nozero.sh

This assumes bashisms, but bash is required to run the tests. This is mostly simple refactoring. Except for the test-memory*.sh tests where nbdkit used to run in the foreground, but that seems to be a consequence of some left over debugging. --- tests/functions.sh.in | 35 ++++++++++++++++++++ tests/test-blocksize.sh | 23 +++---------- tests/test-cache.sh

This assumes bashisms, but bash is required to run the tests. This is mostly refactoring. However the changes (simplifications) are quite substantial: - Since the new start_nbdkit helper function cleans up nbdkit on exit, most scripts no longer need to deal with the pid or kill the pid in the cleanup function. - As a result, cleanup functions are radically simpler, and often

--- docs/nbdkit-captive.pod | 4 ++-- docs/nbdkit-plugin.pod | 2 +- docs/nbdkit-service.pod | 2 +- docs/nbdkit-tls.pod | 2 +- filters/cow/nbdkit-cow-filter.pod | 4 ++-- filters/delay/nbdkit-delay-filter.pod | 2 +- filters/error/nbdkit-error-filter.pod | 6 +++---

--- docs/nbdkit-captive.pod | 4 ++-- docs/nbdkit-plugin.pod | 2 +- docs/nbdkit-service.pod | 2 +- docs/nbdkit-tls.pod | 2 +- filters/cow/nbdkit-cow-filter.pod | 4 ++-- filters/delay/nbdkit-delay-filter.pod | 2 +- filters/error/nbdkit-error-filter.pod | 6 +++---

Combine much common code into tests/functions.sh. Patch 1: Preparation for patch 3. Patch 2: Fix a long-standing bug in how man pages links are generated. Patch 3: Common code for iterating a test function over every plugin. Patch 4: Common code for starting nbdkit in a test and waiting for the PID file to appear. This is the largest and most complex of the patches but is

While our plugin code always advertises WRITE_ZEROES on writable connections (because we can emulate .zero by calling .pwrite), and FUA support when .flush exists (because we can emulate the persistence by calling .flush), it is conceivable that a filter may want to explicitly avoid advertising particular bits. (More to the point, I plan on writing a 'nozero' filter that hides

v1 was here: https://www.redhat.com/archives/libguestfs/2018-September/msg00057.html v2: - Fix tab vs spaces in configure.ac. - To generate list of plugins, use printf instead of xargs. - Use 'source ./functions.sh' instead of 'source functions'. - functions.sh: Consistent quoting in foreach_plugin function. - functions.sh: Change the contract of start_nbdkit so it

Remove the need to use file= (and in future other) parameters for many plugins. eg. Using the file plugin becomes: nbdkit file disk.img Rich.

v1 was here: https://www.redhat.com/archives/libguestfs/2018-September/msg00024.html v2: - As discussed in the patch review, tighten up the characters permitted in keys. - Update documentation to note that relative paths can be made safe by prefixing with ./ and absolute paths do not need any extra steps. - I pushed patch 1/6 from the v1 series since it was just a trivial

v1: https://www.redhat.com/archives/libguestfs/2018-September/msg00024.html v2: https://www.redhat.com/archives/libguestfs/2018-September/msg00034.html v3: - Fixed is_config_key zero length test. - Fixed is_config_key so it uses strspn and is not O(n^2). - Changed >= 1.7 to >= 1.8 in the documentation. Rich.

When we added support for .extents, we had nbdkit unconditionally support structured replies if the client requests them, and the plugin's .can_extents has no impact on what the server advertises. However, while the plugin API doesn't care whether the client requested SR, there is still a case to be made for allowing a filter to prevent SR, at least for testing purposese (such as

After more than a month since v2 [1], I've finally got my FUA support series polished. This is all of my outstanding patches, even though some of them were originally posted in separate threads from the original FUA post [2], [3] [1] https://www.redhat.com/archives/libguestfs/2018-January/msg00113.html [2] https://www.redhat.com/archives/libguestfs/2018-January/msg00219.html [3]

Allow plugins to affect the handling of the new NBD_CMD_FLAG_FAST_ZERO flag, then update affected plugins. In particular, in-memory plugins are always fast; the full plugin is better served by omitting .zero and relying on .pwrite fallback; nbd takes advantage of libnbd extensions proposed in parallel to pass through support; and v2 language bindings expose the choice to their scripts. The

This pair of calls allows plugins to describe which extents in the virtual disk are allocated, holes or zeroes. --- docs/nbdkit-filter.pod | 22 +++++++++++ docs/nbdkit-plugin.pod | 86 +++++++++++++++++++++++++++++++++++++++++ include/nbdkit-common.h | 14 ++++++- include/nbdkit-filter.h | 12 +++++- include/nbdkit-plugin.h | 6 ++- server/internal.h | 7 +++- server/filters.c |

>From the protocol document: "NBD_FLAG_CAN_MULTI_CONN: Indicates that the server operates entirely without cache, or that the cache it uses is shared among all connections to the given device. In particular, if this flag is present, then the effects of NBD_CMD_FLUSH and NBD_CMD_FLAG_FUA MUST be visible across all connections when the server sends its reply to that command to

Similar to the previous patch in caching size, we want to avoid calling into the plugin more than once per connection on any of the flag determination callbacks. The following script demonstrates the speedup, where we avoid repeated calls into a slow can_fua. Pre-patch: $ cat script case "$1" in get_size) echo 1m;; can_fua) sleep 1; echo native;; can_write | can_zero |

nbdkit_debug implicitly prints the plugin name. However this leads to confusing debug messages such as: nbdkit: pattern[1]: debug: prepare nbdkit: pattern[1]: debug: prepare (in this instance, two different prepare functions were called in different filters, but neither filter name was shown). By printing the filter name in the debug message we improve the output: nbdkit: pattern[1]:

This pair of calls allows plugins to describe which extents in the virtual disk are allocated, holes or zeroes. --- docs/nbdkit-filter.pod | 45 +++++++++++++++++ docs/nbdkit-plugin.pod | 106 ++++++++++++++++++++++++++++++++++++++++ include/nbdkit-common.h | 18 ++++++- include/nbdkit-filter.h | 12 ++++- include/nbdkit-plugin.h | 6 ++- server/internal.h | 7 ++- server/extents.c

Thanks: Eric Blake for the suggestion here: https://www.redhat.com/archives/libguestfs/2018-September/msg00069.html --- tests/functions.sh.in | 25 +++++++++++++++++++++++++ tests/test-blocksize.sh | 9 ++------- tests/test-cache.sh | 9 ++------- tests/test-cow.sh | 9 ++------- tests/test-data-7E.sh | 9