vfs functions

[Rajat Sharma]

Mohit,

>From your mails it looks to me you are coming very early to post
questions on this list. I would suggest to be little patient and go
through some text books (preferably Understanding Linux Kernel 3rd
Ed.) and try to cover all I/O subsystem related chapters. I am sure
most of your answers you will find reading text only.

> well by something i mean , that some process needs to access the offset of
> file for next read or dup that file discriptor  so why  each time to go for
> inode . (check me if i am wrong)

are you saying that process refers to inode for getting next read
location? If this is the case, then you are wrong. next read/write
location is kept in file object not in inode. file object is like a
session between process opening the file and inode of the file. A
process (or multiple process) can open a file multiple times creating
multiple file objects against a single inode, with each file object
reading/writing different portions of same file.

Rajat

On Wed, Jan 12, 2011 at 5:38 PM, mohit verma <mohit89mlnc at gmail.com> wrote:
>
>
> On Wed, Jan 12, 2011 at 5:08 PM, prabhu <prabhum at msys-tech.com> wrote:
>>
>> mohit verma wrote:
>>
>> hi folks,
>>
>> i am confused with the functions starting from vfs_ . i  think they show
>> the significance of VFS model  i  mean if something could be done without
>> touching the  disk stuff then why not to do that
>> but i am not quite sure. so please help me understand what does these
>> actually mean??
>>
>> thanks in advance guysss
>
>  well by something i mean , that some process needs to access the offset of
> file for next read or dup that file discriptor  so why  each time to go for
> inode . (check me if i am wrong)
>
>  m sorry for not being clear in textual work.
>
>>  but i got it now . thank  u  for  noticing this query.
>>
>> I am not sure that I understand the above question correctly, you mean
>> "what is the use of VFS file system if doing operation without touching
>> the disk .
>> That means doing operation on cd rom, keyboard,mouse ?"
>>
>> VFS is a upper layer of all the filesystem and all the module register its
>> file operation into this layer.
>> So Whenever you doing operation on any file, VFS layer receive the request
>> and redirect into corresponding
>> registered module operation.
>>
>> I don't think we can do the operation without vfs.
>>
>> Please correct me if i am wrong.
>>
>> Thanks ,
>> Skm prabhu
>>
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>
>
>
> --
> ........................
> MOHIT VERMA
>
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