This patch changes mpage_readpages() and get_block() to get the disk mapping
information for multiple blocks at the same time.

b_size represents the amount of disk mapping that needs to mapped.  On the
successful get_block() b_size indicates the amount of disk mapping thats
actually mapped.  Only the filesystems who care to use this information and
provide multiple disk blocks at a time can choose to do so.

No changes are needed for the filesystems who wants to ignore this.

[akpm@osdl.org: cleanups]
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The return value of this function is never used, so let's be honest and
declare it as void.

Some places where invalidatepage returned 0, I have inserted comments
suggesting a BUG_ON.

[akpm@osdl.org: JBD BUG fix]
[akpm@osdl.org: rework for git-nfs]
[akpm@osdl.org: don't go BUG in block_invalidate_page()]
Signed-off-by: NNeil Brown <neilb@suse.de>
Acked-by: NDave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

rewrite clustering. This prevents writing excessive amounts of clean data
when doing random rewrites of a cached file.

SGI-PV: 951193
SGI-Modid: xfs-linux-melb:xfs-kern:25531a
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

the trace.

SGI-PV: 948300
SGI-Modid: xfs-linux-melb:xfs-kern:208069a
Signed-off-by: NYingping Lu <yingping@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

prep for nobh, someday, maybe).

SGI-PV: 904196
SGI-Modid: xfs-linux-melb:xfs-kern:25481a
Signed-off-by: NNathan Scott <nathans@sgi.com>

SGI-PV: 947038
SGI-Modid: xfs-linux-melb:xfs-kern:25474a
Signed-off-by: NNathan Scott <nathans@sgi.com>

naming.

SGI-PV: 950556
SGI-Modid: xfs-linux-melb:xfs-kern:25378a
Signed-off-by: NNathan Scott <nathans@sgi.com>

SGI-PV: 950211
SGI-Modid: xfs-linux-melb:xfs-kern:25312a
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNathan Scott <nathans@sgi.com>

writepages code. 

SGI-PV: 950211
SGI-Modid: xfs-linux-melb:xfs-kern:25311a
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNathan Scott <nathans@sgi.com>

obscure corruption case

SGI-PV: 942658
SGI-Modid: xfs-linux-melb:xfs-kern:207119a
Signed-off-by: NEric Sandeen <sandeen@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

the clustering of extra pages in a buffered write.

SGI-PV: 949210
SGI-Modid: xfs-linux-melb:xfs-kern:25130a
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

Migrate a page with buffers without requiring writeback

This introduces a new address space operation migratepage() that may be used
by a filesystem to implement its own version of page migration.

A version is provided that migrates buffers attached to pages.  Some
filesystems (ext2, ext3, xfs) are modified to utilize this feature.

The swapper address space operation are modified so that a regular
migrate_page() will occur for anonymous pages without writeback (migrate_pages
forces every anonymous page to have a swap entry).
Signed-off-by: NMike Kravetz <kravetz@us.ibm.com>
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

a page while we are still submitting other buffers on the same page for
I/O.

SGI-PV: 948197
SGI-Modid: xfs-linux-melb:xfs-kern:25004a
Signed-off-by: NDavid Chinner <dgc@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

SGI-PV: 947206
SGI-Modid: xfs-linux-melb:xfs-kern:203960a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

trylock and deal with block layer congestion properly.	Patch from David
Chinner and Christoph Hellwig.

SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203830a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

performances on rewrites since we can reduce the number of allocator
calls.

SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203829a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203828a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

case is very similar to delayed and unwritten extends. Reorganize the code
to share some code for these cases.

SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203827a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

handling offets  From David Chinner and Christoph Hellwig

SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203826a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

page and a relative offset into that page around, and returns the current
xfs_iomap_t if the block at the specified offset fits into it, or a NULL
pointer otherwise.  This patch passed the full 64bit offset into the inode
that all callers have anyway, and changes the return value to a simple
boolean.  Also the function gets a more descriptive name: xfs_iomap_valid.

SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203825a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

lookups and avoids unessecary look roundtrips.

SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203823a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

allows us to submit much larger I/Os instead of sending down lots of small
buffer_heads.  To do this we need to have a rather complicated I/O
submission and completion tracking infrastructure.  Part of the latter has
been merged already a long time ago for direct I/O support. Part of the
problem is that we need to track sub-pagesize regions and for that we
still need buffer_heads for the time beeing.  Long-term I hope we can move
to better data strucutures and/or maybe move this to fs/mpage.c instead of
having it in XFS.  Original patch from Nathan Scott with various updates
from David Chinner and Christoph Hellwig.

SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203822a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

finally.

SGI-PV: 947038
SGI-Modid: xfs-linux-melb:xfs-kern:24866a
Signed-off-by: NNathan Scott <nathans@sgi.com>

direct write.

SGI-PV: 944820
SGI-Modid: xfs-linux-melb:xfs-kern:24351a
Signed-off-by: NNathan Scott <nathans@sgi.com>

SGI-PV: 944819
SGI-Modid: xfs-linux:xfs-kern:24236a
Signed-off-by: NNathan Scott <nathans@sgi.com>

buffers.

SGI-PV: 944820
SGI-Modid: xfs-linux:xfs-kern:24223a
Signed-off-by: NNathan Scott <nathans@sgi.com>

boilerplate.

SGI-PV: 913862
SGI-Modid: xfs-linux:xfs-kern:23903a
Signed-off-by: NNathan Scott <nathans@sgi.com>

SGI-PV: 943122
SGI-Modid: xfs-linux:xfs-kern:23901a
Signed-off-by: NNathan Scott <nathans@sgi.com>

 - ->releasepage() annotated (s/int/gfp_t), instances updated
 - missing gfp_t in fs/* added
 - fixed misannotation from the original sweep caught by bitwise checks:
   XFS used __nocast both for gfp_t and for flags used by XFS allocator.
   The latter left with unsigned int __nocast; we might want to add a
   different type for those but for now let's leave them alone.  That,
   BTW, is a case when __nocast use had been actively confusing - it had
   been used in the same code for two different and similar types, with
   no way to catch misuses.  Switch of gfp_t to bitwise had caught that
   immediately...

One tricky bit is left alone to be dealt with later - mapping->flags is
a mix of gfp_t and error indications.  Left alone for now.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

(luckily just cosmetic).

SGI-PV: 942232
SGI-Modid: xfs-linux-melb:xfs-kern:23718a
Signed-off-by: NNathan Scott <nathans@sgi.com>

SGI-PV: 936584
SGI-Modid: xfs-linux:xfs-kern:196886a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

because aio+dio completions may happen from irq context but we need
process context for converting unwritten extents.  We also queue regular
direct I/O completions to workqueue for regularity, there's only one
queue_work call per syscall.

SGI-PV: 934766
SGI-Modid: xfs-linux:xfs-kern:196857a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

SGI-PV: 934766
SGI-Modid: xfs-linux:xfs-kern:196856a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

time

SGI-PV: 934766
SGI-Modid: xfs-linux:xfs-kern:196854a
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
Signed-off-by: NNathan Scott <nathans@sgi.com>

SGI-PV: 938410
SGI-Modid: xfs-linux:xfs-kern:22966a
Signed-off-by: NNathan Scott <nathans@sgi.com>

XFS will have to look at iocb->private to fix aio+dio.  No other filesystem
is using the blockdev_direct_IO* end_io callback.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

[XFS] Use the right offset when ensuring a delayed allocate conversion has covered the offset originally requested.  Can cause data corruption when multiple processes are performing writeout on different areas of the same file.  Quite difficult to hit though.

SGI Modid: xfs-linux:xfs-kern:22377a
Signed-off-by: NNathan Scott <nathans@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@sgi.com>
.

SGI Modid: xfs-linux:xfs-kern:22376a
Signed-off-by: NNathan Scott <nathans@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@sgi.com>

SGI Modid: xfs-linux:xfs-kern:191586a
Signed-off-by: NDaniel Moore <dxm@sgi.com>
Signed-off-by: NChristoph Hellwig <hch@sgi.com>