Re: Propagating Read-Only?
Re: Propagating Read-Only?
- Subject: Re: Propagating Read-Only?
- From: Duane Murphy <email@hidden>
- Date: Thu, 11 Feb 2010 16:45:10 -0800
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
Thank you Kevin.
That's the route that I have been trying to go down. However, I'm not
working out the unmount incantation. This is especially difficult with
a USB disk. I seems that I need to get all of the IOMedia to be
recreated after changing to the state.
Thoughts on how that can be accomplished?
Thanks again!
...Duane
On Feb 11, 2010, at 4:00 PM, Kevin Elliott wrote:
> You should not be changing this state while the media is mounted.
> Doing so has unpredictable consequences, varying between "bizarre"
> and "catastrophic". A read/write filesystem expects to be able to
> write data to it's target, so changing that value unpredictably will
> corrupt the file system as it's metadata writes fail to complete.
>
> On the other hand, if you only change the state when the volume is
> unmounted (unmount, make read only, remount, etc..) my experience
> has been that very thing will work as expected.
>
> -Kevin
>
>
> On Feb 11, 2010, at 2:54 PM, Duane Murphy wrote:
>
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA256
>>
>> We have a block storage driver kext that can we would like to be able
>> to change from read-write to read-only dynamically.
>>
>> I've worked out how to change the driver to read-only and the
>> underlying IOMedia object. But the read-only change doesn't propagate
>> any further to the file system IOMedia objects or the file system.
>>
>> If the underlying media is changed to read-only then an error is
>> returned by the file system. However, if the media is then changed
>> back to read-write, the file system continues to display an error.
>> I'm
>> fine with the error, the problem in this case is getting the file
>> system to try again so that it is successful.
>>
>> How can I go about updating the file system so that it is aware that
>> the media has changed to read-only and then later back to read-write?
>>
>> Thanks for any tips,
>>
>> ...Duane
>>
>>
>>
>>
>> -----BEGIN PGP SIGNATURE-----
>> Version: PGP Desktop 9.10.0 (Build 500)
>> Charset: US-ASCII
>>
>> wsBVAwUBS3SKo0rg9acQ4r2CAQj5DwgA9zRRyL5bb8B2HkBs0bH0BhJwzc3LUukj
>> sWMKIkM2ZMw80gED7ZT1ZPckxVReSDAaEKfe3usM8G3R1KMmq+CQansvm6y6J5lu
>> R6r4sDb66POoR2l3xgQ8+iwo/Wl/oCCr/kNQC2DcgmQnD3X41+im3P0YV/NTafZB
>> loaitvKGu95nXzVs8eEAkV0oz36Cxi0DhiPWBAzcA/A67sWot0NvaSo3Q0xec49M
>> ztfJamVtNhOYrT2FknHXxUWKoiEDJcg+RNbdoRQa3W/JuOeiEL/X2mL1BA4ZuFYE
>> SsNqk5aJixcVtcZ1w7KSGfR69oAu6vzOlrRErfxKrHUUaax9mcdc2g==
>> =g48r
>> -----END PGP SIGNATURE-----
>> _______________________________________________
>> Do not post admin requests to the list. They will be ignored.
>> Darwin-kernel mailing list (email@hidden)
>> Help/Unsubscribe/Update your Subscription:
>>
>> This email sent to email@hidden
>
...Duane
-----BEGIN PGP SIGNATURE-----
Version: PGP Desktop 9.10.0 (Build 500)
Charset: US-ASCII
wsBVAwUBS3Skn0rg9acQ4r2CAQjQcwgAoFVm4q/0AnveLBcUczRoEdtMRUTC6oic
OC5FEsphFL5SY3bhsqbFEEbTZ9g9HlqYg9Yh4nWBWx+/tdCaI7P5vGPIvdgmz/hD
ilDkn6/L2xdKAjDeaTH8trnj0D2uboab1GEzaXJ6u2r1N/VY4/8N2qSKsmcnh3q9
2CN3iMP9YPrvJTgBbHgX8+ggRkaIowCe3sc6JAIugrettYl5QF4x14894XqADM3g
nLnLtG+DWkyEZ+CM+I02SnBsaG7vSwj2ecxfHHJR5la6vlVck4+nf+tZvyMDCkYV
3M8PHAo5hotBmKnYM+YbaCpI2inPHOKIeH7X61LXUUAqUYMbTbTpLg==
=5yrG
-----END PGP SIGNATURE-----
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Darwin-kernel mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden