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[Qemu-devel] [PATCH v7 11/42] Return path: socket_writev_buffer: Block e
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[Qemu-devel] [PATCH v7 11/42] Return path: socket_writev_buffer: Block even on non-blocking fd's |
Date: |
Tue, 16 Jun 2015 11:26:24 +0100 |
From: "Dr. David Alan Gilbert" <address@hidden>
The destination sets the fd to non-blocking on incoming migrations;
this also affects the return path from the destination, and thus we
need to make sure we can safely write to the return path.
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
migration/qemu-file-unix.c | 41 ++++++++++++++++++++++++++++++++++++-----
1 file changed, 36 insertions(+), 5 deletions(-)
diff --git a/migration/qemu-file-unix.c b/migration/qemu-file-unix.c
index 561621e..b6c55ab 100644
--- a/migration/qemu-file-unix.c
+++ b/migration/qemu-file-unix.c
@@ -39,12 +39,43 @@ static ssize_t socket_writev_buffer(void *opaque, struct
iovec *iov, int iovcnt,
QEMUFileSocket *s = opaque;
ssize_t len;
ssize_t size = iov_size(iov, iovcnt);
+ ssize_t offset = 0;
+ int err;
- len = iov_send(s->fd, iov, iovcnt, 0, size);
- if (len < size) {
- len = -socket_error();
- }
- return len;
+ while (size > 0) {
+ len = iov_send(s->fd, iov, iovcnt, offset, size);
+
+ if (len > 0) {
+ size -= len;
+ offset += len;
+ }
+
+ if (size > 0) {
+ err = socket_error();
+
+ if (err != EAGAIN && err != EWOULDBLOCK) {
+ error_report("socket_writev_buffer: Got err=%d for (%zd/%zd)",
+ err, size, len);
+ /*
+ * If I've already sent some but only just got the error, I
+ * could return the amount validly sent so far and wait for the
+ * next call to report the error, but I'd rather flag the error
+ * immediately.
+ */
+ return -err;
+ }
+
+ /* Emulate blocking */
+ GPollFD pfd;
+
+ pfd.fd = s->fd;
+ pfd.events = G_IO_OUT | G_IO_ERR;
+ pfd.revents = 0;
+ g_poll(&pfd, 1 /* 1 fd */, -1 /* no timeout */);
+ }
+ }
+
+ return offset;
}
static int socket_get_fd(void *opaque)
--
2.4.3
- [Qemu-devel] [PATCH v7 07/42] ram_debug_dump_bitmap: Dump a migration bitmap as text, (continued)
- [Qemu-devel] [PATCH v7 07/42] ram_debug_dump_bitmap: Dump a migration bitmap as text, Dr. David Alan Gilbert (git), 2015/06/16
- [Qemu-devel] [PATCH v7 08/42] migrate_init: Call from savevm, Dr. David Alan Gilbert (git), 2015/06/16
- [Qemu-devel] [PATCH v7 09/42] Rename save_live_complete to save_live_complete_precopy, Dr. David Alan Gilbert (git), 2015/06/16
- [Qemu-devel] [PATCH v7 10/42] Return path: Open a return path on QEMUFile for sockets, Dr. David Alan Gilbert (git), 2015/06/16
- [Qemu-devel] [PATCH v7 11/42] Return path: socket_writev_buffer: Block even on non-blocking fd's,
Dr. David Alan Gilbert (git) <=
- [Qemu-devel] [PATCH v7 12/42] Migration commands, Dr. David Alan Gilbert (git), 2015/06/16
- [Qemu-devel] [PATCH v7 13/42] Return path: Control commands, Dr. David Alan Gilbert (git), 2015/06/16
- [Qemu-devel] [PATCH v7 14/42] Return path: Send responses from destination to source, Dr. David Alan Gilbert (git), 2015/06/16