Merge branch 'master' of /home/davem/src/GIT/linux-2.6/

Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into sh/for-2.6.33

Merge branch 'reiserfs/kill-bkl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing

* 'reiserfs/kill-bkl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-traci

Merge branch 'reiserfs/kill-bkl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing

* 'reiserfs/kill-bkl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing: (31 commits)
kill-the-bkl/reiserfs: turn GFP_ATOMIC flag to GFP_NOFS in reiserfs_get_block()
kill-the-bkl/reiserfs: drop the fs race watchdog from _get_block_create_0()
kill-the-bkl/reiserfs: definitely drop the bkl from reiserfs_ioctl()
kill-the-bkl/reiserfs: always lock the ioctl path
kill-the-bkl/reiserfs: fix reiserfs lock to cpu_add_remove_lock dependency
kill-the-bkl/reiserfs: Fix induced mm->mmap_sem to sysfs_mutex dependency
kill-the-bkl/reiserfs: panic in case of lock imbalance
kill-the-bkl/reiserfs: fix recursive reiserfs write lock in reiserfs_commit_write()
kill-the-bkl/reiserfs: fix recursive reiserfs lock in reiserfs_mkdir()
kill-the-bkl/reiserfs: fix "reiserfs lock" / "inode mutex" lock inversion dependency
kill-the-bkl/reiserfs: move the concurrent tree accesses checks per superblock
kill-the-bkl/reiserfs: acquire the inode mutex safely
kill-the-bkl/reiserfs: unlock only when needed in search_by_key
kill-the-bkl/reiserfs: use mutex_lock in reiserfs_mutex_lock_safe
kill-the-bkl/reiserfs: factorize the locking in reiserfs_write_end()
kill-the-bkl/reiserfs: reduce number of contentions in search_by_key()
kill-the-bkl/reiserfs: don't hold the write recursively in reiserfs_lookup()
kill-the-bkl/reiserfs: lock only once on reiserfs_get_block()
kill-the-bkl/reiserfs: conditionaly release the write lock on fs_changed()
kill-the-BKL/reiserfs: add reiserfs_cond_resched()
...

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reiserfs: kill-the-BKL

This patch is an attempt to remove the Bkl based locking scheme from
reiserfs and is intended.

It is a bit inspired from an old attempt by Peter Zijlstra:

http://lkml.ind

reiserfs: kill-the-BKL

This patch is an attempt to remove the Bkl based locking scheme from
reiserfs and is intended.

It is a bit inspired from an old attempt by Peter Zijlstra:

http://lkml.indiana.edu/hypermail/linux/kernel/0704.2/2174.html

The bkl is heavily used in this filesystem to prevent from
concurrent write accesses on the filesystem.

Reiserfs makes a deep use of the specific properties of the Bkl:

- It can be acqquired recursively by a same task
- It is released on the schedule() calls and reacquired when schedule() returns

The two properties above are a roadmap for the reiserfs write locking so it's
very hard to simply replace it with a common mutex.

- We need a recursive-able locking unless we want to restructure several blocks
of the code.
- We need to identify the sites where the bkl was implictly relaxed
(schedule, wait, sync, etc...) so that we can in turn release and
reacquire our new lock explicitly.
Such implicit releases of the lock are often required to let other
resources producer/consumer do their job or we can suffer unexpected
starvations or deadlocks.

So the new lock that replaces the bkl here is a per superblock mutex with a
specific property: it can be acquired recursively by a same task, like the
bkl.

For such purpose, we integrate a lock owner and a lock depth field on the
superblock information structure.

The first axis on this patch is to turn reiserfs_write_(un)lock() function
into a wrapper to manage this mutex. Also some explicit calls to
lock_kernel() have been converted to reiserfs_write_lock() helpers.

The second axis is to find the important blocking sites (schedule...(),
wait_on_buffer(), sync_dirty_buffer(), etc...) and then apply an explicit
release of the write lock on these locations before blocking. Then we can
safely wait for those who can give us resources or those who need some.
Typically this is a fight between the current writer, the reiserfs workqueue
(aka the async commiter) and the pdflush threads.

The third axis is a consequence of the second. The write lock is usually
on top of a lock dependency chain which can include the journal lock, the
flush lock or the commit lock. So it's dangerous to release and trying to
reacquire the write lock while we still hold other locks.

This is fine with the bkl:

T1 T2

lock_kernel()
mutex_lock(A)
unlock_kernel()
// do something
lock_kernel()
mutex_lock(A) -> already locked by T1
schedule() (and then unlock_kernel())
lock_kernel()
mutex_unlock(A)
....

This is not fine with a mutex:

T1 T2

mutex_lock(write)
mutex_lock(A)
mutex_unlock(write)
// do something
mutex_lock(write)
mutex_lock(A) -> already locked by T1
schedule()

mutex_lock(write) -> already locked by T2
deadlock

The solution in this patch is to provide a helper which releases the write
lock and sleep a bit if we can't lock a mutex that depend on it. It's another
simulation of the bkl behaviour.

The last axis is to locate the fs callbacks that are called with the bkl held,
according to Documentation/filesystem/Locking.

Those are:

- reiserfs_remount
- reiserfs_fill_super
- reiserfs_put_super

Reiserfs didn't need to explicitly lock because of the context of these callbacks.
But now we must take care of that with the new locking.

After this patch, reiserfs suffers from a slight performance regression (for now).
On UP, a high volume write with dd reports an average of 27 MB/s instead
of 30 MB/s without the patch applied.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Bron Gondwana <brong@fastmail.fm>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
LKML-Reference: <1239070789-13354-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

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Merge commit 'v2.6.30-rc5' into next

Merge branch 'master' into next

Merge branch 'fix/pcm-jiffies-check' into fix/asoc

Merge branch 'linus' into x86/mm

Merge reason: refresh the topic: there's been 290 non-merges commits upstream
to arch/x86 alone.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

Merge branch 'for-2.6.30' into for-2.6.31

Merge commit 'v2.6.30-rc1' into sched/urgent

Merge reason: update to latest upstream to queue up fix

Signed-off-by: Ingo Molnar <mingo@elte.hu>

Merge commit 'origin/master' into for-linus/xen/master

* commit 'origin/master': (4825 commits)
Fix build errors due to CONFIG_BRANCH_TRACER=y
parport: Use the PCI IRQ if offered
tty: jsm clea

Merge commit 'origin/master' into for-linus/xen/master

* commit 'origin/master': (4825 commits)
Fix build errors due to CONFIG_BRANCH_TRACER=y
parport: Use the PCI IRQ if offered
tty: jsm cleanups
Adjust path to gpio headers
KGDB_SERIAL_CONSOLE check for module
Change KCONFIG name
tty: Blackin CTS/RTS
Change hardware flow control from poll to interrupt driven
Add support for the MAX3100 SPI UART.
lanana: assign a device name and numbering for MAX3100
serqt: initial clean up pass for tty side
tty: Use the generic RS485 ioctl on CRIS
tty: Correct inline types for tty_driver_kref_get()
splice: fix deadlock in splicing to file
nilfs2: support nanosecond timestamp
nilfs2: introduce secondary super block
nilfs2: simplify handling of active state of segments
nilfs2: mark minor flag for checkpoint created by internal operation
nilfs2: clean up sketch file
nilfs2: super block operations fix endian bug
...

Conflicts:
arch/x86/include/asm/thread_info.h
arch/x86/lguest/boot.c
drivers/xen/manage.c

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Merge branch 'linus' into tracing/core

Merge reason: update to upstream tracing facilities

Signed-off-by: Ingo Molnar <mingo@elte.hu>

Merge branch 'linus' into tracing/hw-branch-tracing

Merge reason: update to latest tracing and ptrace APIs

Signed-off-by: Ingo Molnar <mingo@elte.hu>

Merge branch 'linus' into core/softlockup

Conflicts:
kernel/sysctl.c

Merge branch 'linus' into perfcounters/core-v2

Merge reason: we have gathered quite a few conflicts, need to merge upstream

Conflicts:
arch/powerpc/kernel/Makefile
arch/x86/ia32/ia32entry.S
arch

Merge branch 'linus' into perfcounters/core-v2

Merge reason: we have gathered quite a few conflicts, need to merge upstream

Conflicts:
arch/powerpc/kernel/Makefile
arch/x86/ia32/ia32entry.S
arch/x86/include/asm/hardirq.h
arch/x86/include/asm/unistd_32.h
arch/x86/include/asm/unistd_64.h
arch/x86/kernel/cpu/common.c
arch/x86/kernel/irq.c
arch/x86/kernel/syscall_table_32.S
arch/x86/mm/iomap_32.c
include/linux/sched.h
kernel/Makefile

Signed-off-by: Ingo Molnar <mingo@elte.hu>

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Merge branch 'linus' into irq/threaded

Conflicts:
include/linux/irq.h
kernel/irq/handle.c

Merge branch 'linus' into release

Conflicts:
arch/x86/kernel/cpu/cpufreq/longhaul.c

Signed-off-by: Len Brown <len.brown@intel.com>

Merge branch 'smsc911x-armplatforms' of git://github.com/steveglen/linux-2.6

Merge branch 'linus' into x86/urgent

Merge needed to go past commit 7ca43e756 (mm: use debug_kmap_atomic)
and fix it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

Merge branch 'linus' into locking-for-linus

Conflicts:
lib/Kconfig.debug

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

Merge branch 'linus' into cpumask-for-linus

Conflicts:
arch/x86/kernel/cpu/common.c

Merge branch 'reiserfs-updates' from Jeff Mahoney

* reiserfs-updates: (35 commits)
reiserfs: rename [cn]_* variables
reiserfs: rename p_._ variables
reiserfs: rename p_s_tb to tb
reiserfs: r

Merge branch 'reiserfs-updates' from Jeff Mahoney

* reiserfs-updates: (35 commits)
reiserfs: rename [cn]_* variables
reiserfs: rename p_._ variables
reiserfs: rename p_s_tb to tb
reiserfs: rename p_s_inode to inode
reiserfs: rename p_s_bh to bh
reiserfs: rename p_s_sb to sb
reiserfs: strip trailing whitespace
reiserfs: cleanup path functions
reiserfs: factor out buffer_info initialization
reiserfs: add atomic addition of selinux attributes during inode creation
reiserfs: use generic readdir for operations across all xattrs
reiserfs: journaled xattrs
reiserfs: use generic xattr handlers
reiserfs: remove i_has_xattr_dir
reiserfs: make per-inode xattr locking more fine grained
reiserfs: eliminate per-super xattr lock
reiserfs: simplify xattr internal file lookups/opens
reiserfs: Clean up xattrs when REISERFS_FS_XATTR is unset
reiserfs: remove IS_PRIVATE helpers
reiserfs: remove link detection code
...

Fixed up conflicts manually due to:
- quota name cleanups vs variable naming changes:
fs/reiserfs/inode.c
fs/reiserfs/namei.c
fs/reiserfs/stree.c
fs/reiserfs/xattr.c
- exported include header cleanups
include/linux/reiserfs_fs.h

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reiserfs: Clean up xattrs when REISERFS_FS_XATTR is unset

The current reiserfs xattr implementation will not clean up old xattr
files if files are deleted when REISERFS_FS_XATTR is unset. This
resu

reiserfs: Clean up xattrs when REISERFS_FS_XATTR is unset

The current reiserfs xattr implementation will not clean up old xattr
files if files are deleted when REISERFS_FS_XATTR is unset. This
results in inaccessible lost files, wasting space.

This patch compiles in basic xattr knowledge, such as how to delete them
and change ownership for quota tracking. If the file system has never
used xattrs, then the operation is quite fast: it returns immediately
when it sees there is no .reiserfs_priv directory.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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Merge ../linus