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  1. Dec 22, 2006
    • Andrew Morton's avatar
      [PATCH] truncate: clear page dirtiness before running try_to_free_buffers() · 3e67c098
      Andrew Morton authored 
      

truncate presently invalidates the dirty page's buffer_heads then shoots down
the page.  But try_to_free_buffers() will now bale out because the page is
dirty.

Net effect: the LRU gets filled with dirty pages which have invalidated
buffer_heads attached.  They have no ->mapping and hence cannot be cleaned.
The machine leaks memory at an enormous rate.

Fix this by cleaning the page before running try_to_free_buffers(), so
try_to_free_buffers() can do its work.

Also, remember to do dirty-page-acoounting in cancel_dirty_page() so the
machine won't wedge up trying to write non-existent dirty pages.

Probably still wrong, but now less so.

Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      3e67c098
    • David Chinner's avatar
      [PATCH] Fix XFS after clear_page_dirty() removal · 92132021
      David Chinner authored 
      

XFS appears to call clear_page_dirty to get the mapping tree dirty tag
set correctly at the same time the page dirty flag is cleared.  I note
that this can be done by set_page_writeback() if we clear the dirty flag
on the page first when we are writing back the entire page.

Hence it seems to me that the XFS call to clear_page_dirty() could
easily be substituted by clear_page_dirty_for_io() followed by a call to
set_page_writeback() to get the mapping tree tags set correctly after
the page has been marked clean.

Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      92132021
    • Miklos Szeredi's avatar
      [PATCH] fuse: remove clear_page_dirty() call · 9280f682
      Miklos Szeredi authored 
      

The use by FUSE was just a remnant of an optimization from the time
when writable mappings were supported.

Now FUSE never actually allows the creation of dirty pages, so this
invocation of clear_page_dirty() is effectively a no-op.

Signed-off-by: default avatarMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      9280f682
    • Dave Kleikamp's avatar
      [PATCH] Fix JFS after clear_page_dirty() removal · d0e671a9
      Dave Kleikamp authored 
      

This patch removes some questionable code that attempted to make a
no-longer-used page easier to reclaim.

Calling metapage_writepage against such a page will not result in any
I/O being performed, so removing this code shouldn't be a big deal.

[ It's likely that we could have just replaced the "clear_page_dirty()"
  call with a call to "cancel_dirty_page()" instead, but in the
  meantime this is cleaner and simpler anyway, so unless there is some
  overriding reason (and Dave implies there isn't) I'll just use this
  patch as-is.			- Linus ]

Signed-off-by: default avatarDave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      d0e671a9
    • Linus Torvalds's avatar
      VM: Remove "clear_page_dirty()" and "test_clear_page_dirty()" functions · fba2591b
      Linus Torvalds authored 
      

They were horribly easy to mis-use because of their tempting naming, and
they also did way more than any users of them generally wanted them to
do.

A dirty page can become clean under two circumstances:

 (a) when we write it out.  We have "clear_page_dirty_for_io()" for
     this, and that function remains unchanged.

     In the "for IO" case it is not sufficient to just clear the dirty
     bit, you also have to mark the page as being under writeback etc.

 (b) when we actually remove a page due to it becoming inaccessible to
     users, notably because it was truncate()'d away or the file (or
     metadata) no longer exists, and we thus want to cancel any
     outstanding dirty state.

For the (b) case, we now introduce "cancel_dirty_page()", which only
touches the page state itself, and verifies that the page is not mapped
(since cancelling writes on a mapped page would be actively wrong as it
is still accessible to users).

Some filesystems need to be fixed up for this: CIFS, FUSE, JFS,
ReiserFS, XFS all use the old confusing functions, and will be fixed
separately in subsequent commits (with some of them just removing the
offending logic, and others using clear_page_dirty_for_io()).

This was confirmed by Martin Michlmayr to fix the apt database
corruption on ARM.

Cc: Martin Michlmayr <tbm@cyrius.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Andrei Popa <andrei.popa@i-neo.ro>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Gordon Farquharson <gordonfarquharson@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      fba2591b
    • Linus Torvalds's avatar
      Clean up and make try_to_free_buffers() not race with dirty pages · 46d2277c
      Linus Torvalds authored 
      This is preparatory work in our continuing saga on some hard-to-trigger
file corruption with shared writable mmap() after the dirty page
tracking changes (commit d08b3851

 etc)
were merged.

Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      46d2277c
  3. Dec 21, 2006