Patchwork [v2] raw-posix: Detect legacy floppy via ioctl

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Submitter Cole Robinson
Date Jan. 12, 2010, 3:29 p.m.
Message ID <1263310152-4443-2-git-send-email-crobinso@redhat.com>
Download mbox | patch
Permalink /patch/42733/
State New
Headers show

Comments

Cole Robinson - Jan. 12, 2010, 3:29 p.m.
Current legacy floppy detection is hardcoded based on source file
name. Make this smarter by attempting a floppy specific ioctl.

v2: Give ioctl check higher priority than filename check,
    s/IDE/legacy/

Signed-off-by: Cole Robinson <crobinso@redhat.com>
---
 block/raw-posix.c |   20 ++++++++++++++++++--
 1 files changed, 18 insertions(+), 2 deletions(-)
Christoph Hellwig - Jan. 12, 2010, 5:12 p.m.
Looks good,

same comment applies as to the cdrom one.
Anthony Liguori - Jan. 13, 2010, 11:07 p.m.
On 01/12/2010 09:29 AM, Cole Robinson wrote:
> Current legacy floppy detection is hardcoded based on source file
> name. Make this smarter by attempting a floppy specific ioctl.
>
> v2: Give ioctl check higher priority than filename check,
>      s/IDE/legacy/
>
> Signed-off-by: Cole Robinson<crobinso@redhat.com>
> ---
>   block/raw-posix.c |   20 ++++++++++++++++++--
>   1 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index b7254d8..d67280e 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -1055,9 +1055,25 @@ static int floppy_open(BlockDriverState *bs, const char *filename, int flags)
>
>   static int floppy_probe_device(const char *filename)
>   {
> +    int fd, ret, prio;
> +    struct floppy_struct fdparam;
> +
>       if (strstart(filename, "/dev/fd", NULL))
> -        return 100;
> -    return 0;
> +        prio = 50;
> +
> +    fd = open(filename, O_RDONLY | O_NONBLOCK);
> +    if (fd<  0) {
> +        goto out;
> +    }
> +
> +    /* Attempt to detect via a floppy specific ioctl */
> +    ret = ioctl(fd, FDGETPRM,&fdparam);
> +    if (!(ret<  0&&  errno == EINVAL))
>    

These two patches break boot from an image file.  My suspicious is that 
it's failing because the errno is ENOSYS.

You probably want to do the opposite and check for a positive return 
result instead of checking for the absence of a positive result.

Regards,

Anthony Liguori
Cole Robinson - Jan. 13, 2010, 11:44 p.m.
On 01/13/2010 06:07 PM, Anthony Liguori wrote:
> On 01/12/2010 09:29 AM, Cole Robinson wrote:
>> Current legacy floppy detection is hardcoded based on source file
>> name. Make this smarter by attempting a floppy specific ioctl.
>>
>> v2: Give ioctl check higher priority than filename check,
>>      s/IDE/legacy/
>>
>> Signed-off-by: Cole Robinson<crobinso@redhat.com>
>> ---
>>   block/raw-posix.c |   20 ++++++++++++++++++--
>>   1 files changed, 18 insertions(+), 2 deletions(-)
>>
>> diff --git a/block/raw-posix.c b/block/raw-posix.c
>> index b7254d8..d67280e 100644
>> --- a/block/raw-posix.c
>> +++ b/block/raw-posix.c
>> @@ -1055,9 +1055,25 @@ static int floppy_open(BlockDriverState *bs,
>> const char *filename, int flags)
>>
>>   static int floppy_probe_device(const char *filename)
>>   {
>> +    int fd, ret, prio;
>> +    struct floppy_struct fdparam;
>> +
>>       if (strstart(filename, "/dev/fd", NULL))
>> -        return 100;
>> -    return 0;
>> +        prio = 50;
>> +
>> +    fd = open(filename, O_RDONLY | O_NONBLOCK);
>> +    if (fd<  0) {
>> +        goto out;
>> +    }
>> +
>> +    /* Attempt to detect via a floppy specific ioctl */
>> +    ret = ioctl(fd, FDGETPRM,&fdparam);
>> +    if (!(ret<  0&&  errno == EINVAL))
>>    
> 
> These two patches break boot from an image file.  My suspicious is that
> it's failing because the errno is ENOSYS.
> 

Ugh, sorry about that.

> You probably want to do the opposite and check for a positive return
> result instead of checking for the absence of a positive result.
> 

Sounds good.

Thanks,
Cole

Patch

diff --git a/block/raw-posix.c b/block/raw-posix.c
index b7254d8..d67280e 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -1055,9 +1055,25 @@  static int floppy_open(BlockDriverState *bs, const char *filename, int flags)
 
 static int floppy_probe_device(const char *filename)
 {
+    int fd, ret, prio;
+    struct floppy_struct fdparam;
+
     if (strstart(filename, "/dev/fd", NULL))
-        return 100;
-    return 0;
+        prio = 50;
+
+    fd = open(filename, O_RDONLY | O_NONBLOCK);
+    if (fd < 0) {
+        goto out;
+    }
+
+    /* Attempt to detect via a floppy specific ioctl */
+    ret = ioctl(fd, FDGETPRM, &fdparam);
+    if (!(ret < 0 && errno == EINVAL))
+        prio = 100;
+
+    close(fd);
+out:
+    return prio;
 }