site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com -- Terry Terry, -----Original Message----- From: Terry Lambert [mailto:tlambert@apple.com] Sent: Wednesday, July 29, 2009 11:22 AM To: Kalpana Maheswaram Cc: 'Dan Markarian'; 'darwin-kernel@lists.apple.com' Subject: Re: How to map my filter scheme on to a disk partition? This is described in more detail at: -- Terry Hai Dan, I had gone through the the example of SampleFilterScheme. It works fine for the diskimage which i had created through hdiutil. Read/ write calls in sample filter scheme driver works fine when i write or read on this partition. I have four partitons with Apple_HFS partition content hint which i had created during installation of MAC OS X. I want to know what i need to change inorder to map the SampleFilterScheme on to the four partitions. Regards, Kalpana.M From: Dan Markarian [mailto:markarian@apple.com] Sent: Tuesday, July 28, 2009 10:17 PM To: Kalpana Maheswaram Cc: 'darwin-kernel@lists.apple.com' Subject: Re: How to map my filter scheme on to a disk partition? Hey Kalpana, http://developer.apple.com/samplecode/SampleFilterScheme/index.html Dan On 27 Jul 2009, at 10:26 PM, Kalpana Maheswaram wrote: Dear All, I have my own filter scheme which i want to map on to the existing disk partition. I have went through below mail-listings but unable to work with the provided info. Please help. http://lists.apple.com/archives/darwin-kernel/2005/Jan/msg00043.html http://lists.apple.com/archives/darwin-kernel/2005/Feb/msg00088.html http://lists.apple.com/archives/darwin-kernel/2005/Feb/msg00089.html With Regards, DasariK _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... Are you still trying to grab Apple_HFS disks with this, or are you only grabbing your own disk partition types? When you use the example code the way it tells you to use it, do you still have this problem? The repeating suffix on the device name indicates that you are probably grabbing the IOMedia object you yourself are exporting, which is exactly what I told you to avoid in my last email. The errno 63 is ENAMETOOLONG, which is exactly what you'd expect from doing that as well, once you reached the limit for how long a BSD device name is allowed to get. On Jul 30, 2009, at 3:12 AM, Kalpana Maheswaram <kalpanam@blueally.com> wrote: I went through "Introduction to Mass Storage Device Driver Programming Guide", and driver stack. As suggested I also worked, using UUID (i.e UUID value of the partition from IORegistryExplorer), instead of "Apple_HFS". On loading this using kextload, system got stuck. On restarting the system, log lines from the kext are continuosly logged on to the screen at boot time. I think this into a never ending loop with "devfs:disk0s1s1s1s1s1s1..... name slot allocation failed(Errno=63)" error. If those mailing lists threads are your reference material, there are a couple things you/they are doing wrong. The first is that you are trying to interpose a filter scheme driver between the IOMedia object and the KEXT which normally claims this object on behalf of the OS, which is AppleFileSystemDriver.kext. You really can't do this. Matching is by the Content Hint, and that KEXT gets to have first shot at claiming the IOMedia object based on the Content Hint value, which is done in the mediaNotificationHandler function (where the probe code lives). The sample code that Dan pointed to goes way out of its way to demonstrate how to use hdiutil so that you are not colliding with another KEXT, like AppleFileSystemDriver.kext, by trying to claim something that belongs to it (and not to your KEXT). The second is that even if you were successful interposing yourself there and stole the Content Hint of "Apple_HFS" away from the AppleFileSystemDriver.kext, in order for the file system to later be recognized by the system, you'd have to re-export an IOMedia object with the same "Apple_HFS" Content Hint value so that the driver that's actually supposed to be handling it handles it instead. At that point, you'd probably blow up, since you'd try to claim that device as well because you are going off the Content Hint, which would be matching (again). Basically, you are not really permitted to interpose that way; instead, as the example code Dan pointed you at indicates, you need to use a different Content Hint value, preferably unique to your filter scheme, preferably a UUID value rather than a string like "Apple_HFS". Then the IOMedia object your filter scheme driver publishes needs to publish a block device that has the Content Hint of "Apple_HFS" (or "48465300-0000-11AA-AA11-00306543ECAC", which is the APPLE_HFS_UUID value). In other words, if you want to take over a device at the IOMedia layer, you need to label it as belonging to your KEXT in a way that doesn't end up confusing the OS. This is not a Windows IFSMgr level interface. <http://developer.apple.com/documentation/DeviceDrivers/Conceptual/MassStorag... Which is the "Introduction to Mass Storage Device Driver Programming Guide", but the most important part of that's going to be the last 5 paragraphs of the "Mass Storage Overview" and the stack pictures on that page. On Jul 28, 2009, at 9:51 PM, Kalpana Maheswaram wrote: But when i specify "Content Hint" property as Apple_HFS which i think is the default content hint for the partitions created on MAC OS X and load my filter scheme driver which also has this property with the value Apple_HFS i doesn't get the read/write IOLogs on the console and sees only start and init function IOLogs repeatedly. Ahead Together, Kalpana Maheshwaram Software Engineer | BlueAlly (A Megasoft Division) Megasoft Limited| 6-3-1192/2/1| Kundanbagh| Begumpet| Hyderabad-16| Phone: +91 40 4033 0000 Extension 8033 Mobile: +91 984 998 3755 Email: kalpanam@blueally.com _______________________________________________ Do not post admin requests to the list. They will be ignored. 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