search for: full_pread

...e @@ -111,6 +111,20 @@ full_can_cache (void *handle) return NBDKIT_CACHE_NATIVE; } +/* Always sparse. */ +static int +full_init_sparse (void *handle) +{ + return 1; +} + +/* Always reads as zero. */ +static int +full_init_zero (void *handle) +{ + return 1; +} + /* Read data. */ static int full_pread (void *handle, void *buf, uint32_t count, uint64_t offset, @@ -167,6 +181,8 @@ static struct nbdkit_plugin plugin = { .get_size = full_get_size, .can_multi_conn = full_can_multi_conn, .can_cache = full_can_cache, + .init_sparse = full_init_sparse, + .init_zero...

...y, nbdkit defaults to + * permitting fast zeroes which respond with ENOTSUP, while normal + * zeroes fall back to pwrite and respond with ENOSPC. + */ /* Trim. */ static int @@ -172,7 +169,6 @@ static struct nbdkit_plugin plugin = { .can_cache = full_can_cache, .pread = full_pread, .pwrite = full_pwrite, - .zero = full_zero, .trim = full_trim, .extents = full_extents, /* In this plugin, errno is preserved properly along error return diff --git a/plugins/memory/memory.c b/plugins/memory/memory.c index 09162ea2..e831a...

I will be following up to this email with four separate threads each addressed to the appropriate single list, with proposed changes to: - the NBD protocol - qemu: both server and client - libnbd: client - nbdkit: server The feature in question adds a new optional NBD_INFO_ packet to the NBD_OPT_GO portion of handshake, adding up to 16 bits of information that the server can advertise to the

Since v1: - rework .can_cache to be tri-state, with default of no advertisement (ripple effect through other patches) - add a lot more patches in order to round out filter support And in the meantime, Rich pushed NBD_CMD_CACHE support into libnbd, so in theory we now have a way to test cache commands through the entire stack. Eric Blake (24): server: Internal hooks for implementing

This is a cover letter to a series of patches being proposed in tandem to four different projects: - nbd: Document a new NBD_CMD_FLAG_FAST_ZERO command flag - qemu: Implement the flag for both clients and server - libnbd: Implement the flag for clients - nbdkit: Implement the flag for servers, including the nbd passthrough client If you want to test the patches together, I've pushed a