From: 房海峰 <fhf25@126.com>
To: 房海峰 <fhf25@126.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Subject: Re: a problem from blktap?
Date: Tue, 7 Jul 2009 17:47:38 +0800 [thread overview]
Message-ID: <200907071747377228985@126.com> (raw)
In-Reply-To: 200907071719004656785@126.com
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when i open the large file by the mode of O_DIRECT, Can the malloc() be used?
2009-07-07
房海峰
发件人： 房海峰
发送时间： 2009-07-07 17:20:01
收件人： xen-devel
抄送： fanghaifeng
主题： [Xen-devel] a problem from blktap?
hi all,
currently, i am debuging the code derived from block-sync.c, the detail as follow:
=================================================================
struct socket_message_header *msg_hdr;
struct socketmsg_sync_read * msg_body;
int msglen, size;
char * msgbuf = msg;
int ret = 0;
uint64_t offset;
char * iobuf = NULL;
msg_hdr = (struct socket_message_header *)msgbuf;
msg_body = (struct socketmsg_sync_read *)(msgbuf + sizeof(struct socket_message_header));
msglen = msg_hdr->len;
size = msg_body->nb_sectors * msg_body-sector_size;
offset = msg_body->sector * (uint64_t)msg_body->sector_size;
MY_DPRINTF("READ: nb_sectors = %d, sector_size = %d, start_sector = %llu",
msg_body->nb_sectors,
msg_body->sector_size,
msg_body->sector);
//iobuf = calloc(size, sizeof(char));
iobuf = malloc(size);
if (!iobuf)
goto failure;
MY_DPRINTF("IO Buffer memory calloc is ok!");
ret = lseek(image_fd, offset, SEEK_SET);
if (ret != (off_t)-1) {
MY_DPRINTF("after lseek, the position is at %lu", (unsigned long) ret);
MY_DPRINTF("image_fd = %d, iobuf = %p, size = %d", image_fd, iobuf, size);
ret = readn(image_fd, (void*)iobuf, (size_t)size);
if (ret < 0) {
MY_DPRINTF("readn(%s) is error!", strerror(errno));
goto failure;
}
else
{
MY_DPRINTF("readn() is end, and has read [%d] data!", ret);
}
} else
{
MY_DPRINTF("lseek is error(%s)", strerror(errno));
goto failure;
}
MY_DPRINTF("Seek and Read image is ok!");
===================================================================================
the debuging output, which cut from /var/log/message, are as follow:
Jul 7 16:45:07 domain0 remote-blktapctrl[3963]: [hook_new_tapdisk(712)] loop for select(4)............
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_new_tapdisk(715)] select() is end, and ret = 1
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_new_tapdisk(720)] enter hook_read_message().
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_read_message(632)] read() is end, and msglen=32
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_read_message(651)] receive SOCK_MSG_READ message.
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_do_read(502)] READ: nb_sectors = 2, sector_size = 512, start_sector = 2
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_do_read(508)] IO Buffer memory calloc is ok!
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_do_read(513)] after lseek, the position is at 1024
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_do_read(514)] image_fd = 6, iobuf = 0x804f388, size = 1024
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [readn(66)] call readn(fd[6], ptr[0x804f388], n[1024])
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [readn(70)] call read(fd[6], ptr[0x804f388], nleft[1024])
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [readn(73)] read is error (Invalid argument)
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [readn(74)] nread = -1, nleft = 1024, n = 1024
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_do_read(518)] readn(Invalid argument) is error!
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_read_message(653)] hook_do_read() is end, and ret = -1
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_read_message(670)] do with message is error!
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_new_tapdisk(722)] out of hook_read_message().
Jul 7 16:45:11 domain0 remote-blktapctrl[3963]: [hook_new_tapdisk(712)] loop for select(5)............
Jul 7 16:45:21 domain0 remote-blktapctrl[3963]: [hook_new_tapdisk(715)] select() is end, and ret = 0
among the list above, you can find the error message about the "readn" function. to resovle this problem, i have try some methods, BUT all is failure.
varify the mode of opening the file, that is O_RDWR | O_DIRECT | O_LARGEFILE
So, who can help me to do with this problem?
read is error (Invalid argument) ?
thanks a lot!
2009-07-07
房海峰
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next prev parent reply other threads:[~2009-07-07 9:47 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2009-07-07 9:19 a problem from blktap? 房海峰 2009-07-07 9:47 ` 房海峰 [this message] 2009-07-07 16:49 ` jake wires
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