linux-toradex.git/fs/buffer.c, branch v2.6.21

[PATCH] fs: nobh_truncate_page() fix

2007-03-06T17:30:25+00:00

This fixes a regression caused by 22c8ca78f20724676b6006232bf06cc3e9299539.

nobh_prepare_write() no longer marks the page uptodate, so
nobh_truncate_page() needs to do it.

Signed-off-by: Dave Kleikamp 
Cc: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fs: fix nobh data leak

2007-02-21T01:10:15+00:00

nobh_prepare_write leaks data similarly to how simple_prepare_write did. Fix
by not marking the page uptodate until nobh_commit_write time. Again, this
could break weird use-cases, but none appear to exist in the tree.

We can safely remove the set_page_dirty, because as the comment says,
nobh_commit_write does set_page_dirty. If a filesystem wants to allocate
backing store for a page dirtied via mmap, page_mkwrite is the suggested
approach.

Signed-off-by: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fs: fix __block_write_full_page error case buffer submission

2007-02-21T01:10:13+00:00

Andrew noticed that unlocking the page before submitting all buffers for
writeout could cause problems if the IO completes before we've finished
messing around with the page buffers, and they subsequently get freed.

Even if there were no bug, it is a good idea to bring the error case
into line with the common case here.

Signed-off-by: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] warning fix: unsigned->signed

2007-02-12T17:48:29+00:00

While compiling my code with -Wconversion using gcc-trunk, I always get a
bunch of warrning from headers, here is fix for them:

__getblk is alawys called with unsigned argument,
but it takes signed, the same story with __bread,__breadahead and so on.

Signed-off-by: Tomasz Kvarsin
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Make BH_Unwritten a first class bufferhead flag V2

2007-02-12T17:48:27+00:00

Currently, XFS uses BH_PrivateStart for flagging unwritten extent state in a
bufferhead.  Recently, I found the long standing mmap/unwritten extent
conversion bug, and it was to do with partial page invalidation not clearing
the unwritten flag from bufferheads attached to the page but beyond EOF.  See
here for a full explaination:

http://oss.sgi.com/archives/xfs/2006-12/msg00196.html

The solution I have checked into the XFS dev tree involves duplicating code
from block_invalidatepage to clear the unwritten flag from the bufferhead(s),
and then calling block_invalidatepage() to do the rest.

Christoph suggested that this would be better solved by pushing the unwritten
flag into the common buffer head flags and just adding the call to
discard_buffer():

http://oss.sgi.com/archives/xfs/2006-12/msg00239.html

The following patch makes BH_Unwritten a first class citizen.

Signed-off-by: Dave Chinner 
Acked-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] buffer: memorder fix

2007-02-11T19:15:24+00:00

unlock_buffer(), like unlock_page(), must not clear the lock without
ensuring that the critical section is closed.

Mingming later sent the same patch, saying:

  We are running SDET benchmark and saw double free issue for ext3 extended
  attributes block, which complains the same xattr block already being freed (in
  ext3_xattr_release_block()).  The problem could also been triggered by
  multiple threads loop untar/rm a kernel tree.

  The race is caused by missing a memory barrier at unlock_buffer() before the
  lock bit being cleared, resulting in possible concurrent h_refcounter update.
  That causes a reference counter leak, then later leads to the double free that
  we have seen.

  Inside unlock_buffer(), there is a memory barrier is placed *after* the lock
  bit is being cleared, however, there is no memory barrier *before* the bit is
  cleared.  On some arch the h_refcount update instruction and the clear bit
  instruction could be reordered, thus leave the critical section re-entered.

  The race is like this: For example, if the h_refcount is initialized as 1,

  cpu 0:                                   cpu1
  --------------------------------------   -----------------------------------
  lock_buffer() /* test_and_set_bit */
  clear_buffer_locked(bh);
                                          lock_buffer() /* test_and_set_bit */
  h_refcount = h_refcount+1; /* = 2*/     h_refcount = h_refcount + 1; /*= 2 */
                                          clear_buffer_locked(bh);
  ....                                    ......

  We lost a h_refcount here. We need a memory barrier before the buffer head lock
  bit being cleared to force the order of the two writes.  Please apply.

Signed-off-by: Nick Piggin 
Signed-off-by: Mingming Cao 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] remove invalidate_inode_pages()

2007-02-11T18:51:31+00:00

Convert all calls to invalidate_inode_pages() into open-coded calls to
invalidate_mapping_pages().

Leave the invalidate_inode_pages() wrapper in place for now, marked as
deprecated.

Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Fix try_to_free_buffer() locking

2007-01-30T04:20:42+00:00

Fix commit ecdfc9787fe527491baefc22dce8b2dbd5b2908d

Not to put too fine a point on it, but in a nutshell...

	__set_page_dirty_buffers() | try_to_free_buffers()
	---------------------------+---------------------------
	                           | spin_lock(private_lock);
	                           | drop_bufers()
	                           | spin_unlock(private_lock);
	spin_lock(private_lock)    |
	!page_has_buffers()        |
	spin_unlock(private_lock)  |
	SetPageDirty()             |
	                           | cancel_dirty_page()

                          oops!

Signed-off-by: Nick Piggin 
Acked-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Resurrect 'try_to_free_buffers()' VM hackery

2007-01-26T20:47:06+00:00

It's not pretty, but it appears that ext3 with data=journal will clean
pages without ever actually telling the VM that they are clean.  This,
in turn, will result in the VM (and balance_dirty_pages() in particular)
to never realize that the pages got cleaned, and wait forever for an
event that already happened.

Technically, this seems to be a problem with ext3 itself, but it used to
be hidden by 'try_to_free_buffers()' noticing this situation on its own,
and just working around the filesystem problem.

This commit re-instates that hack, in order to avoid a regression for
the 2.6.20 release. This fixes bugzilla 7844:

	http://bugzilla.kernel.org/show_bug.cgi?id=7844

Peter Zijlstra points out that we should probably retain the debugging
code that this removes from cancel_dirty_page(), and I agree, but for
the imminent release we might as well just silence the warning too
(since it's not a new bug: anything that triggers that warning has been
around forever).

Acked-by: Randy Dunlap 
Acked-by: Jens Axboe 
Acked-by: Peter Zijlstra 
Cc: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Revert bd_mount_mutex back to a semaphore

2007-01-12T02:18:21+00:00

Revert bd_mount_mutex back to a semaphore so that xfs_freeze -f /mnt/newtest;
xfs_freeze -u /mnt/newtest works safely and doesn't produce lockdep warnings.

(XFS unlocks the semaphore from a different task, by design.  The mutex
code warns about this)

Signed-off-by: Dave Chinner 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds