Number of IRPS
in [Device Drivers]
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From: ND on 6 May 2008 05:58 I am writing a virtual disk driver which uses a file as a virtual disk. The disk file can be mounted with a drive letter and normally used. Internally, ZwReadFile and ZwWriteFile in the dispatch routine for IRP_MJ_READ and IRP_MJ_WRITE do the job to write on and read from "disk". As far, everything works fine. In this ,after mounting in explorer window if i make any file copy operation,IRP_MJ_WRITE was called. Also,IRP_MJ_WRITE was called many times after i copied a single file.So my question is, How many IRPs will be sent for file copy operation.How the IRPs are formed by IO manager. How i can trace start and end of copy operation. since,in IRP_MJ_WRITE ,I am writing into a file.Also this file is shared between two driver instances. Looking forward to get reply. Thanks , ND
From: Don Burn on 6 May 2008 06:21 You have no way of knowing about copy operations, all you can know is that something is being read or written. Even if you figured out for the shell what the copy rules were, they would be different for CMD.EXE and then for any other program. -- Don Burn (MVP, Windows DDK) Windows 2k/XP/2k3 Filesystem and Driver Consulting Website: http://www.windrvr.com Blog: http://msmvps.com/blogs/WinDrvr Remove StopSpam to reply "ND" <ND(a)discussions.microsoft.com> wrote in message news:1BCB184F-5028-40A1-8B73-885DDF98B0BE(a)microsoft.com... > > I am writing a virtual disk driver which uses a file as a virtual disk. > > The disk file can be mounted with a drive letter and normally used. > Internally, > ZwReadFile and ZwWriteFile in the dispatch routine for IRP_MJ_READ and > IRP_MJ_WRITE do > the job to write on and read from "disk". As far, everything works > fine. > > In this ,after mounting in explorer window if i make any file copy > operation,IRP_MJ_WRITE was called. > > Also,IRP_MJ_WRITE was called many times after i copied a single file.So my > question is, > How many IRPs will be sent for file copy operation.How the IRPs are formed > by IO manager. > How i can trace start and end of copy operation. > > since,in IRP_MJ_WRITE ,I am writing into a file.Also this file is shared > between two driver instances. > > Looking forward to get reply. > > Thanks , > ND > >
From: ND on 6 May 2008 08:44 Hi, I found following reply. Yes i can know through IRP_MJ_WRITE..But how to pre-determine number of IRP_MJ_WRITE requests .Since ,I need to lock a file when write operation starts and need to free at end of write operation. Simply,I need to lock a file until copy or write operation ends.Otherwise how to avoid dispatch routine to be called many times for single copy operation. Looking forward to hear from you. Thanks ND "Don Burn" wrote: > You have no way of knowing about copy operations, all you can know is that > something is being read or written. Even if you figured out for the shell > what the copy rules were, they would be different for CMD.EXE and then for > any other program. > > > -- > Don Burn (MVP, Windows DDK) > Windows 2k/XP/2k3 Filesystem and Driver Consulting > Website: http://www.windrvr.com > Blog: http://msmvps.com/blogs/WinDrvr > Remove StopSpam to reply > > > > "ND" <ND(a)discussions.microsoft.com> wrote in message > news:1BCB184F-5028-40A1-8B73-885DDF98B0BE(a)microsoft.com... > > > > I am writing a virtual disk driver which uses a file as a virtual disk. > > > > The disk file can be mounted with a drive letter and normally used. > > Internally, > > ZwReadFile and ZwWriteFile in the dispatch routine for IRP_MJ_READ and > > IRP_MJ_WRITE do > > the job to write on and read from "disk". As far, everything works > > fine. > > > > In this ,after mounting in explorer window if i make any file copy > > operation,IRP_MJ_WRITE was called. > > > > Also,IRP_MJ_WRITE was called many times after i copied a single file.So my > > question is, > > How many IRPs will be sent for file copy operation.How the IRPs are formed > > by IO manager. > > How i can trace start and end of copy operation. > > > > since,in IRP_MJ_WRITE ,I am writing into a file.Also this file is shared > > between two driver instances. > > > > Looking forward to get reply. > > > > Thanks , > > ND > > > > > > >
From: Maxim S. Shatskih on 6 May 2008 14:24 > How many IRPs will be sent for file copy operation. Nobody knows for sure, this depends, for instance, on what way was used for file copying. > How i can trace start and end of copy operation. You cannot. Reading the source and writing the destination are 2 absolutely unrelated processes to the kernel, the kernel does not know this is a copy. -- Maxim Shatskih, Windows DDK MVP StorageCraft Corporation maxim(a)storagecraft.com http://www.storagecraft.com
From: ND on 7 May 2008 02:46 Hi Maxim Shantskih, Thanks for your reply. We are creating virtual disk within a file and mounts it as a real disk. Normaly only one user can mount that file as disk, and use it. But now we want multiple user can mount this file in network, as real disk in there own PC, and use it.Like NFS. We did this by giving FILE_SHARE_WRITE access to file ,while file creation using ZwCreateFile. With this multiple user(multiple pcs) can mount this file as virtual disk.And when user updates this virtual volume,the disk file is updated. Now problem is ,when mutiple users trying to update from different pcs I could not maintain offset of the diskfile.So the data lost. I could know user operation through IRP_MJ_XXX.But how i can share this file among driver instances. we planned to lock this file for synchronization.or is there any other way to achieve this. Waiting for your reply. Thanks "Maxim S. Shatskih" wrote: > > How many IRPs will be sent for file copy operation. > > Nobody knows for sure, this depends, for instance, on what way was used for > file copying. > > > How i can trace start and end of copy operation. > > You cannot. Reading the source and writing the destination are 2 absolutely > unrelated processes to the kernel, the kernel does not know this is a copy. > > -- > Maxim Shatskih, Windows DDK MVP > StorageCraft Corporation > maxim(a)storagecraft.com > http://www.storagecraft.com > >
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