Enable removing of corrupted pages through truncation
for a bunch of file systems: ext*, xfs, gfs2, ocfs2, ntfs
These should cover most server needs.

I chose the set of migration aware file systems for this
for now, assuming they have been especially audited.
But in general it should be safe for all file systems
on the data area that support read/write and truncate.

Caveat: the hardware error handler does not take i_mutex
for now before calling the truncate function. Is that ok?

Cc: tytso@mit.edu
Cc: hch@infradead.org
Cc: mfasheh@suse.com
Cc: aia21@cantab.net
Cc: hugh.dickins@tiscali.co.uk
Cc: swhiteho@redhat.com
Signed-off-by: NAndi Kleen <ak@linux.intel.com>

Like the page lock change, this also requires name change, so convert the
raw test_and_set bitop to a trylock.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Simplify page cache zeroing of segments of pages through 3 functions

zero_user_segments(page, start1, end1, start2, end2)

        Zeros two segments of the page. It takes the position where to
        start and end the zeroing which avoids length calculations and
	makes code clearer.

zero_user_segment(page, start, end)

        Same for a single segment.

zero_user(page, start, length)

        Length variant for the case where we know the length.

We remove the zero_user_page macro. Issues:

1. Its a macro. Inline functions are preferable.

2. The KM_USER0 macro is only defined for HIGHMEM.

   Having to treat this special case everywhere makes the
   code needlessly complex. The parameter for zeroing is always
   KM_USER0 except in one single case that we open code.

Avoiding KM_USER0 makes a lot of code not having to be dealing
with the special casing for HIGHMEM anymore. Dealing with
kmap is only necessary for HIGHMEM configurations. In those
configurations we use KM_USER0 like we do for a series of other
functions defined in highmem.h.

Since KM_USER0 is depends on HIGHMEM the existing zero_user_page
function could not be a macro. zero_user_* functions introduced
here can be be inline because that constant is not used when these
functions are called.

Also extract the flushing of the caches to be outside of the kmap.

[akpm@linux-foundation.org: fix nfs and ntfs build]
[akpm@linux-foundation.org: fix ntfs build some more]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Steven French <sfrench@us.ibm.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: <linux-ext4@vger.kernel.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Anton Altaparmakov <aia21@cantab.net>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: David Chinner <dgc@sgi.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Steven French <sfrench@us.ibm.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The regression was caused by:
        commit[a32ea1e1] Fix read/truncate race

This causes ntfs_readpage() to be called for a zero i_size inode, which
failed when the file was compressed and non-resident.

Thanks a lot to Mike Galbraith for reporting the issue and tracking down
the commit that caused the regression.

Looking into it I found three bugs which the patch fixes.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>
Tested-by: NMike Galbraith <efault@gmx.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Big thanks go to Mathias Kolehmainen for reporting the bug, providing
debug output and testing the patches I sent him to get it working.

The fix was to stop calling ntfs_attr_set() at mount time as that causes
balance_dirty_pages_ratelimited() to be called which on systems with
little memory actually tries to go and balance the dirty pages which tries
to take the s_umount semaphore but because we are still in fill_super()
across which the VFS holds s_umount for writing this results in a
deadlock.

We now do the dirty work by hand by submitting individual buffers.  This
has the annoying "feature" that mounting can take a few seconds if the
journal is large as we have clear it all.  One day someone should improve
on this by deferring the journal clearing to a helper kernel thread so it
can be done in the background but I don't have time for this at the moment
and the current solution works fine so I am leaving it like this for now.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use zero_user_page() instead of open-coding it.

[akpm@linux-foundation.org: kmap-type fixes]
Signed-off-by: NNate Diller <nate.diller@gmail.com>
Acked-by: NAnton Altaparmakov <aia21@cantab.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The KM_BIO_SRC_IRQ kmap slot requires local irq protection.
Acked-by: NAnton Altaparmakov <aia21@cantab.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Conversion of booleans to: generic-boolean.patch (2006-08-23)
Signed-off-by: NRichard Knutsson <ricknu-0@student.ltu.se>
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Same as with already do with the file operations: keep them in .rodata and
prevents people from doing runtime patching.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The conversion was generated via scripts, and the result was validated
automatically via a script as well.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      from read inode and new inode code paths.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

       address space operations.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      supported by NTFS which is 4096 bytes).

      Minor tidying.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      preparation for the big rewrite of write(2) support in ntfs.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

*** Warning: "bit_spin_lock" [fs/ntfs/ntfs.ko] undefined!
*** Warning: "bit_spin_unlock" [fs/ntfs/ntfs.ko] undefined!

Cc: Anton Altaparmakov <aia21@cantab.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      fs/ntfs/aops.c::ntfs_end_buffer_async_read() to a bit spin lock
      in the first buffer head of a page.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      fs/ntfs/aops.c::ntfs_readpage().
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      where a concurrent truncate has truncated the runlist under our feet.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      lock protection over the buffer submission for i/o which allows the
      removal of the get_bh()/put_bh() pairs for each buffer.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      fs/ntfs/aops.c::ntfs_writepage().
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      for  mft record writing.  I had missed the writepage based mft record
      write code path.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      if the runlist was not mapped at all and a mapping error occured we
      would leave the runlist locked on exit to the function so that the
      next access to the same file would try to take the lock and deadlock.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      better code generation and one less sparse warning in fs/ntfs/aops.c.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

        and handle the case where an attribute is converted from resident
        to non-resident by a concurrent file write.
      - Reorder some operations when converting an attribute from resident
        to non-resident (fs/ntfs/attrib.c) so it is safe wrt concurrent
        ->readpage and ->writepage.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

Signed-off-by: NRandy Dunlap <rddunlap@osdl.org>
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

	helper ntfs_map_runlist_nolock() which is used by ntfs_map_runlist().
	This allows us to map runlist fragments with the runlist lock already
	held without having to drop and reacquire it around the call.  Adapt
	all callers.
      - Change ntfs_find_vcn() to ntfs_find_vcn_nolock() which takes a locked
	runlist.  This allows us to find runlist elements with the runlist
	lock already held without having to drop and reacquire it around the
	call.  Adapt all callers.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      fs/ntfs/aops.c::ntfs_{prepare,commit}_write()() and re-enable it.
      It should be safe now.  (Famous last words...)
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      and abort if it fails again.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

      access to the i_size and other size fields using the size_lock.
Signed-off-by: NAnton Altaparmakov <aia21@cantab.net>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!