Mount and unmount CD

Mount and unmount CD

[Matt Burkhardt]

I'm having a problem with a virtual machine running under RHEL 5.4
64-bit.  I take out the CD / insert a new and the main machine sees the
new cd and makes it available.  However, the virtual machines still see
the old CD.  I've tried mounting the new CD, but it just keeps mounting
what it "thinks" is in there - the old one.

Any ideas?


Matt Burkhardt
Impari Systems, Inc.

mlb@imparisystems.com
http://www.imparisystems.com 
http://www.linkedin.com/in/mlburkhardt 
http://www.twitter.com/matthewboh
502 Fairview Avenue
Frederick, MD  21701
work (301) 682-7901
cell   (301) 802-3235

Re: Mount and unmount CD

[David S. Ahern]

[-- Attachment #1: Type: text/plain, Size: 986 bytes --]

I saw this with RHEL5.3. I ended up hacking qemu to re_open the CD every
so often. See attached.

David


On 04/23/2010 09:10 AM, Matt Burkhardt wrote:
> I'm having a problem with a virtual machine running under RHEL 5.4
> 64-bit.  I take out the CD / insert a new and the main machine sees the
> new cd and makes it available.  However, the virtual machines still see
> the old CD.  I've tried mounting the new CD, but it just keeps mounting
> what it "thinks" is in there - the old one.
> 
> Any ideas?
> 
> 
> Matt Burkhardt
> Impari Systems, Inc.
> 
> mlb@imparisystems.com
> http://www.imparisystems.com 
> http://www.linkedin.com/in/mlburkhardt 
> http://www.twitter.com/matthewboh
> 502 Fairview Avenue
> Frederick, MD  21701
> work (301) 682-7901
> cell   (301) 802-3235
> 
> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

[-- Attachment #2: qemu-cdrom-flush.patch --]
[-- Type: text/plain, Size: 2571 bytes --]

--- qemu/block-raw-posix.c.orig	2010-01-06 22:27:56.000000000 -0700
+++ qemu/block-raw-posix.c	2010-01-06 22:29:51.000000000 -0700
@@ -193,20 +193,40 @@
 static int raw_pread_aligned(BlockDriverState *bs, int64_t offset,
                      uint8_t *buf, int count)
 {
     BDRVRawState *s = bs->opaque;
     int ret;
 
     ret = fd_open(bs);
     if (ret < 0)
         return ret;
 
+    /* media changes are only detected at the host layer when
+     * somethin reopens the cdrom device. Without an event 
+     * notice, we need a heuristic. Try the following which mimics
+     * what is done for floppy drives. Here we reopen the cdrom
+     * after 3 seconds of elapsed time - this should be short
+     * enough to cover a user inserting a new disk and then accessing
+     * it via the CLI/GUI.
+     */
+    if (bs->type == BDRV_TYPE_CDROM) {
+        static int64_t last = 0;
+        int64_t now = qemu_get_clock(rt_clock);
+        if ((now - last) > 3000)
+            ret = cdrom_reopen(bs);
+        else
+		    ret = 0;
+        last = now;
+        if (ret < 0)
+           return ret;
+    }
+
     if (offset >= 0 && lseek(s->fd, offset, SEEK_SET) == (off_t)-1) {
         ++(s->lseek_err_cnt);
         if(s->lseek_err_cnt <= 10) {
             DEBUG_BLOCK_PRINT("raw_pread(%d:%s, %" PRId64 ", %p, %d) [%" PRId64
                               "] lseek failed : %d = %s\n",
                               s->fd, bs->filename, offset, buf, count,
                               bs->total_sectors, errno, strerror(errno));
         }
         return -1;
     }
--- qemu/hw/ide.c.orig	2010-01-06 22:28:02.000000000 -0700
+++ qemu/hw/ide.c	2010-01-06 22:30:45.000000000 -0700
@@ -1456,20 +1456,28 @@
     s->cd_sector_size = sector_size;
 
     /* XXX: check if BUSY_STAT should be set */
     s->status = READY_STAT | SEEK_STAT | DRQ_STAT | BUSY_STAT;
     ide_dma_start(s, ide_atapi_cmd_read_dma_cb);
 }
 
 static void ide_atapi_cmd_read(IDEState *s, int lba, int nb_sectors,
                                int sector_size)
 {
+    if (s->is_cdrom) {
+        static int64_t last = 0;
+        int64_t now = qemu_get_clock(rt_clock);
+        if ((now - last) > 3000)
+            (void) cdrom_reopen(s->bs);
+        last = now;
+    }
+
 #ifdef DEBUG_IDE_ATAPI
     printf("read %s: LBA=%d nb_sectors=%d\n", s->atapi_dma ? "dma" : "pio",
 	lba, nb_sectors);
 #endif
     if (s->atapi_dma) {
         ide_atapi_cmd_read_dma(s, lba, nb_sectors, sector_size);
     } else {
         ide_atapi_cmd_read_pio(s, lba, nb_sectors, sector_size);
     }
 }

Re: Mount and unmount CD

[David S. Ahern]

[-- Attachment #1: Type: text/plain, Size: 1126 bytes --]

oops. the previous patch rides on top of this one.

David


On 04/23/2010 12:18 PM, David S. Ahern wrote:
> I saw this with RHEL5.3. I ended up hacking qemu to re_open the CD every
> so often. See attached.
> 
> David
> 
> 
> On 04/23/2010 09:10 AM, Matt Burkhardt wrote:
>> I'm having a problem with a virtual machine running under RHEL 5.4
>> 64-bit.  I take out the CD / insert a new and the main machine sees the
>> new cd and makes it available.  However, the virtual machines still see
>> the old CD.  I've tried mounting the new CD, but it just keeps mounting
>> what it "thinks" is in there - the old one.
>>
>> Any ideas?
>>
>>
>> Matt Burkhardt
>> Impari Systems, Inc.
>>
>> mlb@imparisystems.com
>> http://www.imparisystems.com 
>> http://www.linkedin.com/in/mlburkhardt 
>> http://www.twitter.com/matthewboh
>> 502 Fairview Avenue
>> Frederick, MD  21701
>> work (301) 682-7901
>> cell   (301) 802-3235
>>
>>
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe kvm" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>

[-- Attachment #2: qemu-reopen-cdrom.patch --]
[-- Type: text/plain, Size: 4080 bytes --]

--- qemu/block-raw-posix.c.orig	2010-01-06 21:46:31.000000000 -0700
+++ qemu/block-raw-posix.c	2010-01-06 21:54:22.000000000 -0700
@@ -107,20 +107,24 @@
     int fd_got_error;
     int fd_media_changed;
 #endif
     uint8_t* aligned_buf;
 } BDRVRawState;
 
 static int posix_aio_init(void);
 
 static int fd_open(BlockDriverState *bs);
 
+#if defined(__linux__)
+int cdrom_reopen(BlockDriverState *bs);
+#endif
+
 static int raw_open(BlockDriverState *bs, const char *filename, int flags)
 {
     BDRVRawState *s = bs->opaque;
     int fd, open_flags, ret;
 
     posix_aio_init();
 
     s->lseek_err_cnt = 0;
 
     open_flags = O_BINARY;
@@ -212,29 +216,32 @@
     if (ret == count)
         goto label__raw_read__success;
 
     DEBUG_BLOCK_PRINT("raw_pread(%d:%s, %" PRId64 ", %p, %d) [%" PRId64
                       "] read failed %d : %d = %s\n",
                       s->fd, bs->filename, offset, buf, count,
                       bs->total_sectors, ret, errno, strerror(errno));
 
     /* Try harder for CDrom. */
     if (bs->type == BDRV_TYPE_CDROM) {
-        lseek(s->fd, offset, SEEK_SET);
-        ret = read(s->fd, buf, count);
-        if (ret == count)
-            goto label__raw_read__success;
-        lseek(s->fd, offset, SEEK_SET);
-        ret = read(s->fd, buf, count);
-        if (ret == count)
+        int i;
+        for (i = 0; i < 2; ++i) {
+#if defined(__linux__)
+            ret = cdrom_reopen(bs);
+            if (ret < 0)
             goto label__raw_read__success;
-
+#endif
+            lseek(s->fd, offset, SEEK_SET);
+            ret = read(s->fd, buf, count);
+            if (ret == count)
+                goto label__raw_read__success;
+        }
         DEBUG_BLOCK_PRINT("raw_pread(%d:%s, %" PRId64 ", %p, %d) [%" PRId64
                           "] retry read failed %d : %d = %s\n",
                           s->fd, bs->filename, offset, buf, count,
                           bs->total_sectors, ret, errno, strerror(errno));
     }
 
 label__raw_read__success:
 
     return ret;
 }
@@ -1025,20 +1032,27 @@
         printf("Floppy opened\n");
 #endif
     }
     if (!last_media_present)
         s->fd_media_changed = 1;
     s->fd_open_time = qemu_get_clock(rt_clock);
     s->fd_got_error = 0;
     return 0;
 }
 
+int cdrom_reopen(BlockDriverState *bs)
+{
+    /* mimics a 'change' monitor command - without the eject */
+    bdrv_close(bs);
+    return bdrv_open2(bs, bs->filename, 0, bs->drv);
+}
+
 static int raw_is_inserted(BlockDriverState *bs)
 {
     BDRVRawState *s = bs->opaque;
     int ret;
 
     switch(s->type) {
     case FTYPE_CD:
         ret = ioctl(s->fd, CDROM_DRIVE_STATUS, CDSL_CURRENT);
         if (ret == CDS_DISC_OK)
             return 1;
--- qemu/hw/ide.c.orig	2010-01-06 21:54:33.000000000 -0700
+++ qemu/hw/ide.c	2010-01-06 21:56:16.000000000 -0700
@@ -29,20 +29,24 @@
 #include "pcmcia.h"
 #include "block.h"
 #include "block_int.h"
 #include "qemu-timer.h"
 #include "sysemu.h"
 #include "ppc_mac.h"
 #include "sh.h"
 #include <console.h>
 #include <syslog.h>
 
+#if defined(__linux__)
+int cdrom_reopen(BlockDriverState *bs);
+#endif
+
 /* debug IDE devices */
 //#define DEBUG_IDE
 //#define DEBUG_IDE_ATAPI
 //#define DEBUG_AIO
 #define USE_DMA_CDROM
 
 /* Bits of HD_STATUS */
 #define ERR_STAT		0x01
 #define INDEX_STAT		0x02
 #define ECC_STAT		0x04	/* Corrected error */
@@ -1363,20 +1367,25 @@
 /* ATAPI DMA support */
 
 /* XXX: handle read errors */
 static void ide_atapi_cmd_read_dma_cb(void *opaque, int ret)
 {
     BMDMAState *bm = opaque;
     IDEState *s = bm->ide_if;
     int data_offset, n;
 
     if (ret < 0) {
+#if defined(__linux__)
+        /* on EIO failure try re-opening file */
+        if (ret == -EIO)
+            (void) cdrom_reopen(s->bs);
+#endif
         ide_atapi_io_error(s, ret);
         goto eot;
     }
 
     if (s->io_buffer_size > 0) {
 	/*
 	 * For a cdrom read sector command (s->lba != -1),
 	 * adjust the lba for the next s->io_buffer_size chunk
 	 * and dma the current chunk.
 	 * For a command != read (s->lba == -1), just transfer

Re: Mount and unmount CD Bug reporting

[David S. Ahern]

It's been a while since I dug into this, as I recall the media change
needs to be detected to flush cached data. I believe mounting and
unmounting the DVD in the host will work as well, as well as dropping
the cache on the host. I needed an event mechanism rather than polling
for a once in a blue moon change hence the patch.

It is not seen with newer OS versions (e.g., Fedora 11, 12) because of
the media polling (hal service I think).

David


On 04/25/2010 09:32 AM, Matt Burkhardt wrote:
> Thanks - but I don't feel comfortable hacking this - I wanted to try and
> get this reported as a bug, but the directions for submitting a bug are
> too restrictive for me to do this.  For example, it says that you have
> to install the latest version of kvm, run and compile it with different
> flags.  If I had a development box, I would be happy to do this, but
> without one, I can't come close to the requirements for submitting a
> bug.  Could someone else do this?  Since two of us are having the same
> issue with two different versions of RHEL, it seems like it would point
> to a bug....
> 
> On Fri, 2010-04-23 at 12:52 -0600, David S. Ahern wrote:
>> oops. the previous patch rides on top of this one.
>>
>> David
>>
>>
>> On 04/23/2010 12:18 PM, David S. Ahern wrote:
>> > I saw this with RHEL5.3. I ended up hacking qemu to re_open the CD every
>> > so often. See attached.
>> > 
>> > David
>> > 
>> > 
>> > On 04/23/2010 09:10 AM, Matt Burkhardt wrote:
>> >> I'm having a problem with a virtual machine running under RHEL 5.4
>> >> 64-bit.  I take out the CD / insert a new and the main machine sees the
>> >> new cd and makes it available.  However, the virtual machines still see
>> >> the old CD.  I've tried mounting the new CD, but it just keeps mounting
>> >> what it "thinks" is in there - the old one.
>> >>
>> >> Any ideas?
>> >>
>> >>
>> >> Matt Burkhardt
>> >> Impari Systems, Inc.
>> >>
>> >> mlb@imparisystems.com <mailto:mlb@imparisystems.com>
>> >> http://www.imparisystems.com 
>> >> http://www.linkedin.com/in/mlburkhardt 
>> >> http://www.twitter.com/matthewboh
>> >> 502 Fairview Avenue
>> >> Frederick, MD  21701
>> >> work (301) 682-7901
>> >> cell   (301) 802-3235
>> >>
>> >>
>> >>
>> >> --
>> >> To unsubscribe from this list: send the line "unsubscribe kvm" in
>> >> the body of a message to majordomo@vger.kernel.org <mailto:majordomo@vger.kernel.org>
>> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> >>
> 
> 
> Matt Burkhardt
> Impari Systems, Inc.
> 
> mlb@imparisystems.com <mailto:mlb@imparisystems.com>
> http://www.imparisystems.com
> http://www.linkedin.com/in/mlburkhardt
> http://www.twitter.com/matthewboh
> 502 Fairview Avenue
> Frederick, MD  21701
> work (301) 682-7901
> cell   (301) 802-3235
> 
>