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Re: [RFC PATCH 20/26] UBIFS: add VFS operations

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To: Pekka Enberg <penberg@...>
Cc: Artem Bityutskiy <Artem.Bityutskiy@...>, LKML <linux-kernel@...>, Adrian Hunter <ext-adrian.hunter@...>
Date: Tuesday, April 1, 2008 - 8:42 am

Pekka Enberg wrote:

In UBIFS pages must never become dirty without asking UBIFS if this is allowed or not.
This is needed because of budgeting - before making any page dirty we have to make
sure there is enough space to write it back. This is not usually an issue for
traditional FSes, because pages may be changed in-place. In UBIFS we cannot change
stuff in-place, so we have to be very careful when marking things dirty. This is why
we have the budgeting sub-system. The white-paper tells more about this.

Anyway, the requirement is that all the places where a page may become dirty
should be in UBIFS and the corresponding operations have to be budgeted for.

If this function is called, this means that someone made a page dirty without
budgeting for this. Which in turn may mean that there will be no space when
the page is written back. So basically, this implementation is just a guarding
check.


Yeah, this is also a guarding thing. When a dirty page is released
the budget which was allocated for it has to be freed. If this function
is called, then the budget was not freed, which must never happen.

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)
--
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Messages in current thread:
[RFC PATCH] UBIFS - new flash file system, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
Re: [RFC PATCH] UBIFS - new flash file system, Thomas Gleixner, (Fri Apr 18, 5:05 am)
Re: [RFC PATCH] UBIFS - new flash file system, Jan Engelhardt, (Mon Mar 31, 8:29 am)
Re: [RFC PATCH] UBIFS - new flash file system, Jörn, (Mon Mar 31, 9:40 am)
Re: [RFC PATCH] UBIFS - new flash file system, Adrian Hunter, (Mon Mar 31, 8:47 am)
Re: [RFC PATCH] UBIFS - new flash file system, Jörn, (Mon Mar 31, 9:20 am)
Re: [RFC PATCH] UBIFS - new flash file system, Artem Bityutskiy, (Mon Mar 31, 10:00 am)
Re: [RFC PATCH] UBIFS - new flash file system, Jörn, (Mon Mar 31, 1:17 pm)
Re: [RFC PATCH] UBIFS - new flash file system, Pekka Enberg, (Mon Mar 31, 4:49 pm)
Re: [RFC PATCH] UBIFS - new flash file system, Jörn, (Mon Mar 31, 5:21 pm)
Re: [RFC PATCH] UBIFS - new flash file system, Artem Bityutskiy, (Tue Apr 1, 2:00 am)
Re: [RFC PATCH] UBIFS - new flash file system, Artem Bityutskiy, (Fri Mar 28, 2:45 am)
Re: [RFC PATCH] UBIFS - new flash file system, Josh Boyer, (Thu Mar 27, 12:20 pm)
Re: [RFC PATCH] UBIFS - new flash file system, Artem Bityutskiy, (Fri Mar 28, 2:17 am)
[RFC PATCH 09/26] UBIFS: add key helpers, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 26/26] UBIFS: include FS to compilation, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Pekka Enberg, (Tue Apr 1, 3:39 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Artem Bityutskiy, (Tue Apr 1, 4:51 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Christoph Hellwig, (Sat Apr 26, 5:35 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Adrian Hunter, (Mon Apr 28, 3:09 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, ext Christoph Hellwig, (Mon Apr 28, 5:00 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Adrian Hunter, (Mon Apr 28, 7:23 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, ext ext Christoph Hellwig..., (Mon Apr 28, 7:39 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Adrian Hunter, (Mon Apr 28, 8:25 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Christoph Hellwig, (Mon Apr 28, 9:02 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Pekka Enberg, (Tue Apr 1, 5:15 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Artem Bityutskiy, (Tue Apr 1, 5:25 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Pekka Enberg, (Tue Apr 1, 6:04 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Artem Bityutskiy, (Tue Apr 1, 6:26 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Pekka Enberg, (Tue Apr 1, 7:33 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Christoph Hellwig, (Sat Apr 26, 5:37 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Adrian Hunter, (Mon Apr 28, 3:10 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, ext Christoph Hellwig, (Mon Apr 28, 5:03 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Adrian Hunter, (Wed Apr 30, 3:04 am)
Re: [RFC PATCH 26/26] UBIFS: include FS to compilation, Artem Bityutskiy, (Tue Apr 1, 7:56 am)
[RFC PATCH 22/26] UBIFS: add extended attribute support, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 04/26] UBIFS: add journal replay, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 03/26] UBIFS: add flash scanning, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 18/26] UBIFS: add LEB find subsystem, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 16/26] UBIFS: add LEB properties tree, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 08/26] UBIFS: add compression support, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 07/26] UBIFS: add file-system recovery, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 06/26] UBIFS: add superblock and master node, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 05/26] UBIFS: add file-system build, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
Re: [RFC PATCH 05/26] UBIFS: add file-system build, Andrew Morton, (Fri Mar 28, 6:12 am)
Re: [RFC PATCH 05/26] UBIFS: add file-system build, Artem Bityutskiy, (Fri Mar 28, 7:04 am)
[RFC PATCH 02/26] UBIFS: add I/O sub-system, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 25/26] UBIFS: add debugging stuff, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
Re: [RFC PATCH 25/26] UBIFS: add debugging stuff, Pekka Enberg, (Mon Mar 31, 5:00 pm)
Re: [RFC PATCH 25/26] UBIFS: add debugging stuff, Artem Bityutskiy, (Tue Apr 1, 2:20 am)
Re: [RFC PATCH 25/26] UBIFS: add debugging stuff, Pekka Enberg, (Tue Apr 1, 3:43 am)
Re: [RFC PATCH 25/26] UBIFS: add debugging stuff, Pekka Enberg, (Tue Apr 1, 3:33 am)
Re: [RFC PATCH 25/26] UBIFS: add debugging stuff, Adrian Hunter, (Tue Apr 1, 4:34 am)
Re: [RFC PATCH 25/26] UBIFS: add debugging stuff, Artem Bityutskiy, (Tue Apr 1, 4:32 am)
Re: [RFC PATCH 25/26] UBIFS: add debugging stuff, Pekka Enberg, (Tue Apr 1, 5:00 am)
Re: [RFC PATCH 25/26] UBIFS: add debugging stuff, Artem Bityutskiy, (Tue Apr 1, 5:04 am)
[RFC PATCH 24/26] UBIFS: add header files, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 23/26] UBIFS: add orphans handling sub-system, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 21/26] UBIFS: add budgeting, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 20/26] UBIFS: add VFS operations, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
Re: [RFC PATCH 20/26] UBIFS: add VFS operations, Pekka Enberg, (Tue Apr 1, 8:08 am)
Re: [RFC PATCH 20/26] UBIFS: add VFS operations, Artem Bityutskiy, (Tue Apr 1, 8:42 am)
Re: [RFC PATCH 20/26] UBIFS: add VFS operations, Pekka Enberg, (Tue Apr 1, 9:12 am)
Re: [RFC PATCH 20/26] UBIFS: add VFS operations, Artem Bityutskiy, (Tue Apr 1, 10:04 am)
Re: [RFC PATCH 20/26] UBIFS: add VFS operations, Adrian Hunter, (Tue Apr 1, 11:14 am)
Re: [RFC PATCH 20/26] UBIFS: add VFS operations, Andi Kleen, (Thu Mar 27, 9:36 am)
Re: [RFC PATCH 20/26] UBIFS: add VFS operations, Artem Bityutskiy, (Thu Mar 27, 9:42 am)
[RFC PATCH 19/26] UBIFS: add Garbage Collector, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
Re: [RFC PATCH 19/26] UBIFS: add Garbage Collector, Arnd Bergmann, (Mon Mar 31, 10:11 pm)
[RFC PATCH 01/26] VFS: introduce writeback_inodes_sb(), Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 17/26] UBIFS: add LEB properties tree, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 15/26] UBIFS: add LEB properties, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 14/26] UBIFS: add TNC shrinker, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 13/26] UBIFS: add TNC commit implementation, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 12/26] UBIFS: add TNC implementation, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 11/26] UBIFS: add commit functionality, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
[RFC PATCH 10/26] UBIFS: add the journal, Artem Bityutskiy, (Thu Mar 27, 10:55 am)
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