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[Qemu-devel] [PATCH v6 12/47] Return path: socket_writev_buffer: Block e
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[Qemu-devel] [PATCH v6 12/47] Return path: socket_writev_buffer: Block even on non-blocking fd's |
Date: |
Tue, 14 Apr 2015 18:03:38 +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 1e7de7b..6b024e5 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)
--
2.1.0
- [Qemu-devel] [PATCH v6 02/47] Split header writing out of qemu_savevm_state_begin, (continued)
- [Qemu-devel] [PATCH v6 02/47] Split header writing out of qemu_savevm_state_begin, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 01/47] Start documenting how postcopy works., Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 04/47] Add qemu_get_counted_string to read a string prefixed by a count byte, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 03/47] qemu_ram_foreach_block: pass up error value, and down the ramblock name, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 05/47] Create MigrationIncomingState, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 06/47] Provide runtime Target page information, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 09/47] Add wrapper for setting blocking status on a QEMUFile, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 07/47] Move copy out of qemu_peek_buffer, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 13/47] Migration commands, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 10/47] Rename save_live_complete to save_live_complete_precopy, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 12/47] Return path: socket_writev_buffer: Block even on non-blocking fd's,
Dr. David Alan Gilbert (git) <=
- [Qemu-devel] [PATCH v6 08/47] Add qemu_get_buffer_less_copy to avoid copies some of the time, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 11/47] Return path: Open a return path on QEMUFile for sockets, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 15/47] Return path: Send responses from destination to source, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 14/47] Return path: Control commands, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 17/47] ram_debug_dump_bitmap: Dump a migration bitmap as text, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 18/47] Move loadvm_handlers into MigrationIncomingState, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 16/47] Return path: Source handling of return path, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 19/47] Rework loadvm path for subloops, Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 20/47] Add migration-capability boolean for postcopy-ram., Dr. David Alan Gilbert (git), 2015/04/14
- [Qemu-devel] [PATCH v6 22/47] MIG_CMD_PACKAGED: Send a packaged chunk of migration stream, Dr. David Alan Gilbert (git), 2015/04/14