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[Qemu-block] [PULL 06/11] nbd/client: refactor nbd_read_eof
From: |
Eric Blake |
Subject: |
[Qemu-block] [PULL 06/11] nbd/client: refactor nbd_read_eof |
Date: |
Wed, 30 Aug 2017 13:07:06 -0500 |
From: Vladimir Sementsov-Ogievskiy <address@hidden>
Refactor nbd_read_eof to return 1 on success, 0 on eof, when no
data was read and <0 for other cases, because returned size of
read data is not actually used.
Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
Message-Id: <address@hidden>
[eblake: tweak function comments, rebase to test 083 enhancements]
Signed-off-by: Eric Blake <address@hidden>
---
nbd/nbd-internal.h | 33 ++++++++++++++++++++++++---------
nbd/client.c | 5 -----
tests/qemu-iotests/083.out | 8 ++++----
3 files changed, 28 insertions(+), 18 deletions(-)
diff --git a/nbd/nbd-internal.h b/nbd/nbd-internal.h
index 396ddb4d3e..03549e3f39 100644
--- a/nbd/nbd-internal.h
+++ b/nbd/nbd-internal.h
@@ -77,21 +77,36 @@
#define NBD_ESHUTDOWN 108
/* nbd_read_eof
- * Tries to read @size bytes from @ioc. Returns number of bytes actually read.
- * May return a value >= 0 and < size only on EOF, i.e. when iteratively called
- * qio_channel_readv() returns 0. So, there is no need to call nbd_read_eof
- * iteratively.
+ * Tries to read @size bytes from @ioc.
+ * Returns 1 on success
+ * 0 on eof, when no data was read (errp is not set)
+ * negative errno on failure (errp is set)
*/
-static inline ssize_t nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,
- Error **errp)
+static inline int nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,
+ Error **errp)
{
struct iovec iov = { .iov_base = buffer, .iov_len = size };
+ ssize_t ret;
+
/* Sockets are kept in blocking mode in the negotiation phase. After
* that, a non-readable socket simply means that another thread stole
* our request/reply. Synchronization is done with recv_coroutine, so
* that this is coroutine-safe.
*/
- return nbd_rwv(ioc, &iov, 1, size, true, errp);
+
+ assert(size);
+
+ ret = nbd_rwv(ioc, &iov, 1, size, true, errp);
+ if (ret <= 0) {
+ return ret;
+ }
+
+ if (ret != size) {
+ error_setg(errp, "End of file");
+ return -EINVAL;
+ }
+
+ return 1;
}
/* nbd_read
@@ -100,9 +115,9 @@ static inline ssize_t nbd_read_eof(QIOChannel *ioc, void
*buffer, size_t size,
static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
Error **errp)
{
- ssize_t ret = nbd_read_eof(ioc, buffer, size, errp);
+ int ret = nbd_read_eof(ioc, buffer, size, errp);
- if (ret >= 0 && ret != size) {
+ if (ret == 0) {
ret = -EINVAL;
error_setg(errp, "End of file");
}
diff --git a/nbd/client.c b/nbd/client.c
index f1c16b588f..4556056daa 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -925,11 +925,6 @@ ssize_t nbd_receive_reply(QIOChannel *ioc, NBDReply
*reply, Error **errp)
return ret;
}
- if (ret != sizeof(buf)) {
- error_setg(errp, "read failed");
- return -EINVAL;
- }
-
/* Reply
[ 0 .. 3] magic (NBD_REPLY_MAGIC)
[ 4 .. 7] error (0 == no error)
diff --git a/tests/qemu-iotests/083.out b/tests/qemu-iotests/083.out
index a7fb081889..fb71b6f8ad 100644
--- a/tests/qemu-iotests/083.out
+++ b/tests/qemu-iotests/083.out
@@ -69,12 +69,12 @@ read failed: Input/output error
=== Check disconnect 4 reply ===
-read failed
+End of file
read failed: Input/output error
=== Check disconnect 8 reply ===
-read failed
+End of file
read failed: Input/output error
=== Check disconnect before data ===
@@ -180,12 +180,12 @@ read failed: Input/output error
=== Check disconnect 4 reply ===
-read failed
+End of file
read failed: Input/output error
=== Check disconnect 8 reply ===
-read failed
+End of file
read failed: Input/output error
=== Check disconnect before data ===
--
2.13.5
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