Let filesystems handle waiting for direct I/O requests themselves instead
of doing it beforehand.  This means filesystem-specific locks to prevent
new dio referenes from appearing can be held.  This is important to allow
generalizing i_dio_count to non-DIO_LOCKING filesystems.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The exportfs encode handle function should return the minimum required
handle size. This helps user to find out the handle size by passing 0
handle size in the first step and then redoing to the call again with
the returned handle size value.
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

The big kernel lock has been removed from all these files at some point,
leaving only the #include.

Remove this too as a cleanup.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This removes more dead code that was somehow missed by commit 0d99519e
(writeback: remove unused nonblocking and congestion checks).  There are
no behavior change except for the removal of two entries from one of the
ext4 tracing interface.

The nonblocking checks in ->writepages are no longer used because the
flusher now prefer to block on get_request_wait() than to skip inodes on
IO congestion.  The latter will lead to more seeky IO.

The nonblocking checks in ->writepage are no longer used because it's
redundant with the WB_SYNC_NONE check.

We no long set ->nonblocking in VM page out and page migration, because
a) it's effectively redundant with WB_SYNC_NONE in current code
b) it's old semantic of "Don't get stuck on request queues" is mis-behavior:
   that would skip some dirty inodes on congestion and page out others, which
   is unfair in terms of LRU age.

Inspired by Christoph Hellwig. Thanks!
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: David Howells <dhowells@redhat.com>
Cc: Sage Weil <sage@newdream.net>
Cc: Steve French <sfrench@samba.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__block_write_begin and block_prepare_write are identical except for slightly
different calling conventions.  Convert all callers to the __block_write_begin
calling conventions and drop block_prepare_write.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

reiserfs_evict_inode calls end_writeback two times hitting
kernel BUG at fs/inode.c:298 becase inode->i_state is I_CLEAR already.
Signed-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Make sure we call inode_change_ok before doing any changes in ->setattr,
and make sure to call it even if our fs wants to ignore normal UNIX
permissions, but use the ATTR_FORCE to skip those.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Replace inode_setattr with opencoded variants of it in all callers.  This
moves the remaining call to vmtruncate into the filesystem methods where it
can be replaced with the proper truncate sequence.

In a few cases it was obvious that we would never end up calling vmtruncate
so it was left out in the opencoded variant:

 spufs: explicitly checks for ATTR_SIZE earlier
 btrfs,hugetlbfs,logfs,dlmfs: explicitly clears ATTR_SIZE earlier
 ufs: contains an opencoded simple_seattr + truncate that sets the filesize just above

In addition to that ncpfs called inode_setattr with handcrafted iattrs,
which allowed to trim down the opencoded variant.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Split up the block_write_begin implementation - __block_write_begin is a new
trivial wrapper for block_prepare_write that always takes an already
allocated page and can be either called from block_write_begin or filesystem
code that already has a page allocated.  Remove the handling of already
allocated pages from block_write_begin after switching all callers that
do it to __block_write_begin.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Move the call to vmtruncate to get rid of accessive blocks to the callers
in prepearation of the new truncate calling sequence.  This was only done
for DIO_LOCKING filesystems, so the __blockdev_direct_IO_newtrunc variant
was not needed anyway.  Get rid of blockdev_direct_IO_no_locking and
its _newtrunc variant while at it as just opencoding the two additional
paramters is shorted than the name suffix.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

a) count file openers correctly; i_count use was completely wrong
b) use new mutex for exclusion between final close/open/truncate,
to protect tailpacking logics.  i_mutex use was wrong and resulted
in deadlocks.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Quota must being initialized if size or uid/git changes requested.
But initialization performed in two different places:
in case of i_size file system is responsible for dquot init
, but in case of uid/gid init will be called internally in
dquot_transfer().
This ambiguity makes code harder to understand.
Let's move this logic to one common helper function.
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NJan Kara <jack@suse.cz>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

This gives the filesystem more information about the writeback that
is happening.  Trond requested this for the NFS unstable write handling,
and other filesystems might benefit from this too by beeing able to
distinguish between the different callers in more detail.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Get rid of the initialize dquot operation - it is now always called from
the filesystem and if a filesystem really needs it's own (which none
currently does) it can just call into it's own routine directly.

Rename the now static low-level dquot_initialize helper to __dquot_initialize
and vfs_dq_init to dquot_initialize to have a consistent namespace.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Currently various places in the VFS call vfs_dq_init directly.  This means
we tie the quota code into the VFS.  Get rid of that and make the
filesystem responsible for the initialization.   For most metadata operations
this is a straight forward move into the methods, but for truncate and
open it's a bit more complicated.

For truncate we currently only call vfs_dq_init for the sys_truncate case
because open already takes care of it for ftruncate and open(O_TRUNC) - the
new code causes an additional vfs_dq_init for those which is harmless.

For open the initialization is moved from do_filp_open into the open method,
which means it happens slightly earlier now, and only for regular files.
The latter is fine because we don't need to initialize it for operations
on special files, and we already do it as part of the namespace operations
for directories.

Add a dquot_file_open helper that filesystems that support generic quotas
can use to fill in ->open.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Get rid of the drop dquot operation - it is now always called from
the filesystem and if a filesystem really needs it's own (which none
currently does) it can just call into it's own routine directly.

Rename the now static low-level dquot_drop helper to __dquot_drop
and vfs_dq_drop to dquot_drop to have a consistent namespace.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Get rid of the transfer dquot operation - it is now always called from
the filesystem and if a filesystem really needs it's own (which none
currently does) it can just call into it's own routine directly.

Rename the now static low-level dquot_transfer helper to __dquot_transfer
and vfs_dq_transfer to dquot_transfer to have a consistent namespace,
and make the new dquot_transfer return a normal negative errno value
which all callers expect.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Get rid of the alloc_inode and free_inode dquot operations - they are
always called from the filesystem and if a filesystem really needs
their own (which none currently does) it can just call into it's
own routine directly.

Also get rid of the vfs_dq_alloc/vfs_dq_free wrappers and always
call the lowlevel dquot_alloc_inode / dqout_free_inode routines
directly, which now lose the number argument which is always 1.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

When we wait for an inode through reiserfs_iget(), we hold
the reiserfs lock. And waiting for an inode may imply waiting
for its writeback. But the inode writeback path may also require
the reiserfs lock, which leads to a deadlock.

We just need to release the reiserfs lock from reiserfs_iget()
to fix this.
Reported-by: NAlexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Tested-by: NChristian Kujau <lists@nerdbynature.de>
Cc: Chris Mason <chris.mason@oracle.com>

While truncating a file, reiserfs_setattr() calls inode_setattr()
that will truncate the mapping for the given inode, but for that
it needs the pages locks.

In order to release these, the owners need the reiserfs lock to
complete their jobs. But they can't, as we don't release it before
calling inode_setattr().

We need to do that to fix the following softlockups:

INFO: task flush-8:0:2149 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
flush-8:0     D f51af998     0  2149      2 0x00000000
 f51af9ac 00000092 00000002 f51af998 c2803304 00000000 c1894ad0 010f3000
 f51af9cc c1462604 c189ef80 f51af974 c1710304 f715b450 f715b5ec c2807c40
 00000000 0005bb00 c2803320 c102c55b c1710304 c2807c50 c2803304 00000246
Call Trace:
 [<c1462604>] ? schedule+0x434/0xb20
 [<c102c55b>] ? resched_task+0x4b/0x70
 [<c106fa22>] ? mark_held_locks+0x62/0x80
 [<c146414d>] ? mutex_lock_nested+0x1fd/0x350
 [<c14640b9>] mutex_lock_nested+0x169/0x350
 [<c1178cde>] ? reiserfs_write_lock+0x2e/0x40
 [<c1178cde>] reiserfs_write_lock+0x2e/0x40
 [<c11719a2>] do_journal_end+0xc2/0xe70
 [<c1172912>] journal_end+0xb2/0x120
 [<c11686b3>] ? pathrelse+0x33/0xb0
 [<c11729e4>] reiserfs_end_persistent_transaction+0x64/0x70
 [<c1153caa>] reiserfs_get_block+0x12ba/0x15f0
 [<c106fa22>] ? mark_held_locks+0x62/0x80
 [<c1154b24>] reiserfs_writepage+0xa74/0xe80
 [<c1465a27>] ? _raw_spin_unlock_irq+0x27/0x50
 [<c11f3d25>] ? radix_tree_gang_lookup_tag_slot+0x95/0xc0
 [<c10b5377>] ? find_get_pages_tag+0x127/0x1a0
 [<c106fa22>] ? mark_held_locks+0x62/0x80
 [<c106fcd4>] ? trace_hardirqs_on_caller+0x124/0x170
 [<c10bc1e0>] __writepage+0x10/0x40
 [<c10bc9ab>] write_cache_pages+0x16b/0x320
 [<c10bc1d0>] ? __writepage+0x0/0x40
 [<c10bcb88>] generic_writepages+0x28/0x40
 [<c10bcbd5>] do_writepages+0x35/0x40
 [<c11059f7>] writeback_single_inode+0xc7/0x330
 [<c11067b2>] writeback_inodes_wb+0x2c2/0x490
 [<c1106a86>] wb_writeback+0x106/0x1b0
 [<c1106cf6>] wb_do_writeback+0x106/0x1e0
 [<c1106c18>] ? wb_do_writeback+0x28/0x1e0
 [<c1106e0a>] bdi_writeback_task+0x3a/0xb0
 [<c10cbb13>] bdi_start_fn+0x63/0xc0
 [<c10cbab0>] ? bdi_start_fn+0x0/0xc0
 [<c105d1f4>] kthread+0x74/0x80
 [<c105d180>] ? kthread+0x0/0x80
 [<c100327a>] kernel_thread_helper+0x6/0x10
3 locks held by flush-8:0/2149:
 #0:  (&type->s_umount_key#30){+++++.}, at: [<c110676f>] writeback_inodes_wb+0x27f/0x490
 #1:  (&journal->j_mutex){+.+...}, at: [<c117199a>] do_journal_end+0xba/0xe70
 #2:  (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c1178cde>] reiserfs_write_lock+0x2e/0x40
INFO: task fstest:3813 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
fstest        D 00000002     0  3813   3812 0x00000000
 f5103c94 00000082 f5103c40 00000002 f5ad5450 00000007 f5103c28 011f3000
 00000006 f5ad5450 c10bb005 00000480 c1710304 f5ad5450 f5ad55ec c2907c40
 00000001 f5ad5450 f5103c74 00000046 00000002 f5ad5450 00000007 f5103c6c
Call Trace:
 [<c10bb005>] ? free_hot_cold_page+0x1d5/0x280
 [<c1462d64>] io_schedule+0x74/0xc0
 [<c10b5a45>] sync_page+0x35/0x60
 [<c146325a>] __wait_on_bit_lock+0x4a/0x90
 [<c10b5a10>] ? sync_page+0x0/0x60
 [<c10b59e5>] __lock_page+0x85/0x90
 [<c105d660>] ? wake_bit_function+0x0/0x60
 [<c10bf654>] truncate_inode_pages_range+0x1e4/0x2d0
 [<c10bf75f>] truncate_inode_pages+0x1f/0x30
 [<c10bf7cf>] truncate_pagecache+0x5f/0xa0
 [<c10bf86a>] vmtruncate+0x5a/0x70
 [<c10fdb7d>] inode_setattr+0x5d/0x190
 [<c1150117>] reiserfs_setattr+0x1f7/0x2f0
 [<c1464569>] ? down_write+0x49/0x70
 [<c10fde01>] notify_change+0x151/0x330
 [<c10e6f3d>] do_truncate+0x6d/0xa0
 [<c10f4ce2>] do_filp_open+0x9a2/0xcf0
 [<c1465aec>] ? _raw_spin_unlock+0x2c/0x50
 [<c10fec50>] ? alloc_fd+0xe0/0x100
 [<c10e602d>] do_sys_open+0x6d/0x130
 [<c1002cfb>] ? sysenter_exit+0xf/0x16
 [<c10e615e>] sys_open+0x2e/0x40
 [<c1002ccc>] sysenter_do_call+0x12/0x32
3 locks held by fstest/3813:
 #0:  (&sb->s_type->i_mutex_key#4){+.+.+.}, at: [<c10e6f33>] do_truncate+0x63/0xa0
 #1:  (&sb->s_type->i_alloc_sem_key#3){+.+.+.}, at: [<c10fdf07>] notify_change+0x257/0x330
 #2:  (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c1178c8e>] reiserfs_write_lock_once+0x2e/0x50
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>

On chown, reiserfs will call reiserfs_setattr() to change the owner
of the given inode, but it may also recursively call
reiserfs_setattr() to propagate the owner change to the private xattr
files for this inode.

Hence, the reiserfs lock may be acquired twice which is not wanted
as reiserfs_setattr() calls journal_begin() that is going to try to
relax the lock in order to safely acquire the journal mutex.

Using reiserfs_write_lock_once() from reiserfs_setattr() solves
the problem.

This fixes the following warning, that precedes a lockdep report.

WARNING: at fs/reiserfs/lock.c:95 reiserfs_lock_check_recursive+0x3f/0x50()
Hardware name: MS-7418
Unwanted recursive reiserfs lock!
Pid: 4189, comm: fsstress Not tainted 2.6.33-rc2-tip-atom+ #195
Call Trace:
 [<c1178bff>] ? reiserfs_lock_check_recursive+0x3f/0x50
 [<c1178bff>] ? reiserfs_lock_check_recursive+0x3f/0x50
 [<c103f7ac>] warn_slowpath_common+0x6c/0xc0
 [<c1178bff>] ? reiserfs_lock_check_recursive+0x3f/0x50
 [<c103f84b>] warn_slowpath_fmt+0x2b/0x30
 [<c1178bff>] reiserfs_lock_check_recursive+0x3f/0x50
 [<c1172ae3>] do_journal_begin_r+0x83/0x350
 [<c1172f2d>] journal_begin+0x7d/0x140
 [<c106509a>] ? in_group_p+0x2a/0x30
 [<c10fda71>] ? inode_change_ok+0x91/0x140
 [<c115007d>] reiserfs_setattr+0x15d/0x2e0
 [<c10f9bf3>] ? dput+0xe3/0x140
 [<c1465adc>] ? _raw_spin_unlock+0x2c/0x50
 [<c117831d>] chown_one_xattr+0xd/0x10
 [<c11780a3>] reiserfs_for_each_xattr+0x113/0x2c0
 [<c1178310>] ? chown_one_xattr+0x0/0x10
 [<c14641e9>] ? mutex_lock_nested+0x2a9/0x350
 [<c117826f>] reiserfs_chown_xattrs+0x1f/0x60
 [<c106509a>] ? in_group_p+0x2a/0x30
 [<c10fda71>] ? inode_change_ok+0x91/0x140
 [<c1150046>] reiserfs_setattr+0x126/0x2e0
 [<c1177c20>] ? reiserfs_getxattr+0x0/0x90
 [<c11b0d57>] ? cap_inode_need_killpriv+0x37/0x50
 [<c10fde01>] notify_change+0x151/0x330
 [<c10e659f>] chown_common+0x6f/0x90
 [<c10e67bd>] sys_lchown+0x6d/0x80
 [<c1002ccc>] sysenter_do_call+0x12/0x32
---[ end trace 7c2b77224c1442fc ]---
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>

It can happen that write does not use all the blocks allocated in
write_begin either because of some filesystem error (like ENOSPC) or
because page with data to write has been removed from memory.  We truncate
these blocks so that we don't have dangling blocks beyond i_size.

Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When we were using the bkl, we didn't care about dependencies against
other locks, but the mutex conversion created new ones, which is why
we have reiserfs_mutex_lock_safe(), which unlocks the reiserfs lock
before acquiring another mutex.

But this trick actually fails if we have acquired the reiserfs lock
recursively, as we try to unlock it to acquire the new mutex without
inverted dependency, but we eventually only decrease its depth.

This happens in the case of a nested inode creation/deletion.
Say we have no space left on the device, we create an inode
and tak the lock but fail to create its entry, then we release the
inode using iput(), which calls reiserfs_delete_inode() that takes
the reiserfs lock recursively. The path eventually ends up in
journal_begin() where we try to take the journal safely but we
fail because of the reiserfs lock recursion:

[ INFO: possible circular locking dependency detected ]
2.6.32-06486-g053fe57a #2
-------------------------------------------------------
vi/23454 is trying to acquire lock:
 (&journal->j_mutex){+.+...}, at: [<c110dac4>] do_journal_begin_r+0x64/0x2f0

but task is already holding lock:
 (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c11106a8>] reiserfs_write_lock+0x28/0x40

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&REISERFS_SB(s)->lock){+.+.+.}:
       [<c104f8f3>] validate_chain+0xa23/0xf70
       [<c1050325>] __lock_acquire+0x4e5/0xa70
       [<c105092a>] lock_acquire+0x7a/0xa0
       [<c134c78f>] mutex_lock_nested+0x5f/0x2b0
       [<c11106a8>] reiserfs_write_lock+0x28/0x40
       [<c110dacb>] do_journal_begin_r+0x6b/0x2f0
       [<c110ddcf>] journal_begin+0x7f/0x120
       [<c10f76c2>] reiserfs_remount+0x212/0x4d0
       [<c1093997>] do_remount_sb+0x67/0x140
       [<c10a9ca6>] do_mount+0x436/0x6b0
       [<c10a9f86>] sys_mount+0x66/0xa0
       [<c1002c50>] sysenter_do_call+0x12/0x36

-> #0 (&journal->j_mutex){+.+...}:
       [<c104fe38>] validate_chain+0xf68/0xf70
       [<c1050325>] __lock_acquire+0x4e5/0xa70
       [<c105092a>] lock_acquire+0x7a/0xa0
       [<c134c78f>] mutex_lock_nested+0x5f/0x2b0
       [<c110dac4>] do_journal_begin_r+0x64/0x2f0
       [<c110ddcf>] journal_begin+0x7f/0x120
       [<c10ef52f>] reiserfs_delete_inode+0x9f/0x140
       [<c10a55fc>] generic_delete_inode+0x9c/0x150
       [<c10a56ed>] generic_drop_inode+0x3d/0x60
       [<c10a4607>] iput+0x47/0x50
       [<c10e915c>] reiserfs_create+0x16c/0x1c0
       [<c109a9c1>] vfs_create+0xc1/0x130
       [<c109dbec>] do_filp_open+0x81c/0x920
       [<c109004f>] do_sys_open+0x4f/0x110
       [<c1090179>] sys_open+0x29/0x40
       [<c1002c50>] sysenter_do_call+0x12/0x36

other info that might help us debug this:

2 locks held by vi/23454:
 #0:  (&sb->s_type->i_mutex_key#5){+.+.+.}, at: [<c109d64e>]
do_filp_open+0x27e/0x920
 #1:  (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c11106a8>]
reiserfs_write_lock+0x28/0x40

stack backtrace:
Pid: 23454, comm: vi Not tainted 2.6.32-06486-g053fe57a #2
Call Trace:
 [<c134b202>] ? printk+0x18/0x1e
 [<c104e960>] print_circular_bug+0xc0/0xd0
 [<c104fe38>] validate_chain+0xf68/0xf70
 [<c104ca9b>] ? trace_hardirqs_off+0xb/0x10
 [<c1050325>] __lock_acquire+0x4e5/0xa70
 [<c105092a>] lock_acquire+0x7a/0xa0
 [<c110dac4>] ? do_journal_begin_r+0x64/0x2f0
 [<c134c78f>] mutex_lock_nested+0x5f/0x2b0
 [<c110dac4>] ? do_journal_begin_r+0x64/0x2f0
 [<c110dac4>] ? do_journal_begin_r+0x64/0x2f0
 [<c110ff80>] ? delete_one_xattr+0x0/0x1c0
 [<c110dac4>] do_journal_begin_r+0x64/0x2f0
 [<c110ddcf>] journal_begin+0x7f/0x120
 [<c11105b5>] ? reiserfs_delete_xattrs+0x15/0x50
 [<c10ef52f>] reiserfs_delete_inode+0x9f/0x140
 [<c10a55bf>] ? generic_delete_inode+0x5f/0x150
 [<c10ef490>] ? reiserfs_delete_inode+0x0/0x140
 [<c10a55fc>] generic_delete_inode+0x9c/0x150
 [<c10a56ed>] generic_drop_inode+0x3d/0x60
 [<c10a4607>] iput+0x47/0x50
 [<c10e915c>] reiserfs_create+0x16c/0x1c0
 [<c1099a5d>] ? inode_permission+0x7d/0xa0
 [<c109a9c1>] vfs_create+0xc1/0x130
 [<c10e8ff0>] ? reiserfs_create+0x0/0x1c0
 [<c109dbec>] do_filp_open+0x81c/0x920
 [<c104ca9b>] ? trace_hardirqs_off+0xb/0x10
 [<c134dc0d>] ? _spin_unlock+0x1d/0x20
 [<c10a6eea>] ? alloc_fd+0xba/0xf0
 [<c109004f>] do_sys_open+0x4f/0x110
 [<c1090179>] sys_open+0x29/0x40
 [<c1002c50>] sysenter_do_call+0x12/0x36

To fix this, use reiserfs_lock_once() from reiserfs_delete_inode()
which prevents from adding reiserfs lock recursion.
Reported-by: NAlexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>

GFP_ATOMIC was used in reiserfs_get_block to not lose the Bkl so that
nobody can modify the tree in the middle of its work. Now that we
kicked out the bkl, we can use a more friendly flag. We use GFP_NOFS
here because we already hold the reiserfs lock.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Laurent Riffard <laurent.riffard@free.fr>
Cc: Thomas Gleixner <tglx@linutronix.de>

We had a watchdog in _get_block_create_0() that jumped to a fixup retry
path in case the bkl got relaxed while calling kmap().
This is not necessary anymore since we now have a reiserfs lock that is
not implicitly relaxed while sleeping.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Laurent Riffard <laurent.riffard@free.fr>
Cc: Thomas Gleixner <tglx@linutronix.de>

reiserfs_commit_write() is always called with the write lock held.
Thus the current calls to reiserfs_write_lock() in this function are
acquiring the lock recursively.
We can safely drop them.

This also solves further assumptions for this lock to be really
released while calling reiserfs_write_unlock().
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Laurent Riffard <laurent.riffard@free.fr>

reiserfs_write_end() is a hot path in reiserfs.
We have two wasteful write lock lock/release inside that can be gathered
without changing the code logic.

This patch factorizes them out in a single protected section, reducing the
number of contentions inside.

[ Impact: reduce lock contention in a reiserfs hotpath ]

Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

reiserfs_get_block() is one of these sites where the write lock might
be acquired recursively.

It's a particular problem because this function is called very often.
It's a hot spot which needs to reschedule() periodically while converting
direct items to indirect ones because it can take some time.

Then if we are applying the write lock release/reacquire pattern on
schedule() here, it may not produce the desired effect since we may have
locked in more than one depth.

The solution is to use reiserfs_write_lock_once() which won't try
to reacquire the lock recursively. Then the lock will be *really*
released before schedule().

Also, we only release the lock if TIF_NEED_RESCHED is set to not
create wasteful numerous contentions.

[ Impact: fix a too long holded lock case in reiserfs_get_block() ]

Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

Impact: fix a deadlock

reiserfs_truncate_file() can be called from multiple context where
the write lock can be already hold or not.

This function also acquire (possibly recursively) the write
lock. Subsequent releases before sleeping will not actually release
the lock because we may be in more than one lock depth degree.

A typical case is:

reiserfs_file_release {
	acquire_the_lock()
	reiserfs_truncate_file()
		reacquire_the_lock()
		journal_begin() {
			do_journal_begin_r() {
				reiserfs_wait_on_write_block() {
					/*
					 * Not released because still one
					 * depth owned
					 */
					release_lock()
					wait_for_event()

At this stage the event never happen because the one which provides
it needs the write lock.

We use reiserfs_write_lock_once() here to ensure that we don't acquire the
write lock recursively.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@texware.it>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
LKML-Reference: <1239680065-25013-3-git-send-email-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

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: NFrederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: NIngo 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: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch is a simple s/p_s_inode/inode/g to the reiserfs code.  This
is the third in a series of patches to rip out some of the awful
variable naming in reiserfs.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch strips trailing whitespace from the reiserfs code.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Some time ago, some changes were made to make security inode attributes
be atomically written during inode creation.  ReiserFS fell behind in
this area, but with the reworking of the xattr code, it's now fairly
easy to add.

The following patch adds the ability for security attributes to be added
automatically during inode creation.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Deadlocks are possible in the xattr code between the journal lock and the
xattr sems.

This patch implements journalling for xattr operations. The benefit is
twofold:
 * It gets rid of the deadlock possibility by always ensuring that xattr
   write operations are initiated inside a transaction.
 * It corrects the problem where xattr backing files aren't considered any
   differently than normal files, despite the fact they are metadata.

I discussed the added journal load with Chris Mason, and we decided that
since xattrs (versus other journal activity) is fairly rare, the introduction
of larger transactions to support journaled xattrs wouldn't be too big a deal.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With the switch to using inode->i_mutex locking during lookups/creation
in the xattr root, the per-super xattr lock is no longer needed.

This patch removes it.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>