5:03 p.m.
If the target server supports FUA, then we should pass the client
flag through rather than emulating things with a less-efficient
flush.
Signed-off-by: Eric Blake <eblake(a)redhat.com>
---
v3: rebase to API changes
---
plugins/nbd/nbd.c | 42 +++++++++++++++++++++++++++++++++---------
1 file changed, 33 insertions(+), 9 deletions(-)
diff --git a/plugins/nbd/nbd.c b/plugins/nbd/nbd.c
index c9727f7..db53746 100644
--- a/plugins/nbd/nbd.c
+++ b/plugins/nbd/nbd.c
@@ -46,6 +46,8 @@
#include <assert.h>
#include <pthread.h>
+#define NBDKIT_API_VERSION 2
+
#include <nbdkit-plugin.h>
#include "protocol.h"
@@ -616,68 +618,89 @@ nbd_can_trim (void *handle)
return h->flags & NBD_FLAG_SEND_TRIM;
}
+static int
+nbd_can_fua (void *handle)
+{
+ struct handle *h = handle;
+
+ return h->flags & NBD_FLAG_SEND_FUA ? NBDKIT_FUA_NATIVE : NBDKIT_FUA_NONE;
+}
+
/* Read data from the file. */
static int
-nbd_pread (void *handle, void *buf, uint32_t count, uint64_t offset)
+nbd_pread (void *handle, void *buf, uint32_t count, uint64_t offset,
+ uint32_t flags)
{
struct handle *h = handle;
int c;
/* TODO Auto-fragment this if the client has a larger max transfer
limit than the server */
+ assert (!flags);
c = nbd_request_full (h, 0, NBD_CMD_READ, offset, count, NULL, buf);
return c < 0 ? c : nbd_reply (h, c);
}
/* Write data to the file. */
static int
-nbd_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset)
+nbd_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset,
+ uint32_t flags)
{
struct handle *h = handle;
int c;
/* TODO Auto-fragment this if the client has a larger max transfer
limit than the server */
- c = nbd_request_full (h, 0, NBD_CMD_WRITE, offset, count, buf, NULL);
+ assert (!(flags & ~NBDKIT_FLAG_FUA));
+ c = nbd_request_full (h, flags & NBDKIT_FLAG_FUA ? NBD_CMD_FLAG_FUA : 0,
+ NBD_CMD_WRITE, offset, count, buf, NULL);
return c < 0 ? c : nbd_reply (h, c);
}
/* Write zeroes to the file. */
static int
-nbd_zero (void *handle, uint32_t count, uint64_t offset, int may_trim)
+nbd_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags)
{
struct handle *h = handle;
int c;
+ int f = 0;
+ assert (!(flags & ~(NBDKIT_FLAG_FUA | NBDKIT_FLAG_MAY_TRIM)));
if (!(h->flags & NBD_FLAG_SEND_WRITE_ZEROES)) {
/* Trigger a fall back to regular writing */
errno = EOPNOTSUPP;
return -1;
}
- c = nbd_request (h, may_trim ? 0 : NBD_CMD_FLAG_NO_HOLE,
- NBD_CMD_WRITE_ZEROES, offset, count);
+ if (!(flags & NBDKIT_FLAG_MAY_TRIM))
+ f |= NBD_CMD_FLAG_NO_HOLE;
+ if (flags & NBDKIT_FLAG_FUA)
+ f |= NBD_CMD_FLAG_FUA;
+ c = nbd_request (h, f, NBD_CMD_WRITE_ZEROES, offset, count);
return c < 0 ? c : nbd_reply (h, c);
}
/* Trim a portion of the file. */
static int
-nbd_trim (void *handle, uint32_t count, uint64_t offset)
+nbd_trim (void *handle, uint32_t count, uint64_t offset, uint32_t flags)
{
struct handle *h = handle;
int c;
- c = nbd_request (h, 0, NBD_CMD_TRIM, offset, count);
+ assert (!(flags & ~NBDKIT_FLAG_FUA));
+ c = nbd_request (h, flags & NBDKIT_FLAG_FUA ? NBD_CMD_FLAG_FUA : 0,
+ NBD_CMD_TRIM, offset, count);
return c < 0 ? c : nbd_reply (h, c);
}
/* Flush the file to disk. */
static int
-nbd_flush (void *handle)
+nbd_flush (void *handle, uint32_t flags)
{
struct handle *h = handle;
int c;
+ assert (!flags);
c = nbd_request (h, 0, NBD_CMD_FLUSH, 0, 0);
return c < 0 ? c : nbd_reply (h, c);
}
@@ -697,6 +720,7 @@ static struct nbdkit_plugin plugin = {
.can_flush = nbd_can_flush,
.is_rotational = nbd_is_rotational,
.can_trim = nbd_can_trim,
+ .can_fua = nbd_can_fua,
.pread = nbd_pread,
.pwrite = nbd_pwrite,
.zero = nbd_zero,
--
2.14.3