jfs has never been setting i_ctime or i_mtime when creating either hard
or symbolic links.  I'm surprised nobody had noticed until now.

Thanks to Chris Spiegel for reporting the problem.

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>

Christoph Lameter demonstrated very poor scalability on the SGI 512-way, with
a many-threaded application which concurrently initializes different parts of
a large anonymous area.

This patch corrects that, by using a separate spinlock per page table page, to
guard the page table entries in that page, instead of using the mm's single
page_table_lock.  (But even then, page_table_lock is still used to guard page
table allocation, and anon_vma allocation.)

In this implementation, the spinlock is tucked inside the struct page of the
page table page: with a BUILD_BUG_ON in case it overflows - which it would in
the case of 32-bit PA-RISC with spinlock debugging enabled.

Splitting the lock is not quite for free: another cacheline access.  Ideally,
I suppose we would use split ptlock only for multi-threaded processes on
multi-cpu machines; but deciding that dynamically would have its own costs.
So for now enable it by config, at some number of cpus - since the Kconfig
language doesn't support inequalities, let preprocessor compare that with
NR_CPUS.  But I don't think it's worth being user-configurable: for good
testing of both split and unsplit configs, split now at 4 cpus, and perhaps
change that to 8 later.

There is a benefit even for singly threaded processes: kswapd can be attacking
one part of the mm while another part is busy faulting.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

The xtTruncate code was only doing this for leaf pages.  When a file is
horribly fragmented, we may truncate a file leaving an internal page with
an invalid head.next field, which may cause a stale page to be referenced.

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.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: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Replace assert statements with better error handling.

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>

This patch fixes up a few problems with jfs's reserved inodes.

1. There is no need for the jfs code setting the I_DIRTY bits in i_state.
   I am ashamed that the code ever did this, and surprised it hasn't been
   noticed until now.

2. Make sure special inodes are on an inode hash list.  If the inodes are
   unhashed, __mark_inode_dirty will fail to put the inode on the
   superblock's dirty list, and the data will not be flushed under memory
   pressure.

3. Force writing journal data to disk when metapage_writepage is unable to
   write a metadata page due to pending journal I/O.

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>

The inode pointer may no longer be valid

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>

The fix in inode.c is a real bug.  It could result in undeleted, yet
unconnected files on big-endian hardware.

The others are trivial.

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>

Clash due to new delete_inode behavior (the filesystem now needs to do
the truncate_inode_pages() call itself).

Signed-off-by: Linus Torvalds <torvalds@osdl.org>