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

Removed vmtruncate
Signed-off-by: NMarco Stornelli <marco.stornelli@gmail.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch stops reiserfs using the VFS 'write_super()' method along with the
s_dirt flag, because they are on their way out.

The whole "superblock write-out" VFS infrastructure is served by the
'sync_supers()' kernel thread, which wakes up every 5 (by default) seconds and
writes out all dirty superblock using the '->write_super()' call-back.  But the
problem with this thread is that it wastes power by waking up the system every
5 seconds, even if there are no diry superblocks, or there are no client
file-systems which would need this (e.g., btrfs does not use
'->write_super()'). So we want to kill it completely and thus, we need to make
file-systems to stop using the '->write_super()' VFS service, and then remove
it together with the kernel thread.
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Turn 'reiserfs_flush_old_commits()' into a void function because the callers
do not cares about what it returns anyway.

We are going to remove the 'sb->s_dirt' field completely and this patch is a
small step towards this direction.
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

pass inode + parent's inode or NULL instead of dentry + bool saying
whether we want the parent or not.

NOTE: that needs ceph fix folded in.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

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

If a header file is making use of BUG, BUG_ON, BUILD_BUG_ON, or any
other BUG variant in a static inline (i.e. not in a #define) then
that header really should be including <linux/bug.h> and not just
expecting it to be implicitly present.

We can make this change risk-free, since if the files using these
headers didn't have exposure to linux/bug.h already, they would have
been causing compile failures/warnings.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Make reiserfs properly display mount options in /proc/mounts.

CC: reiserfs-devel@vger.kernel.org
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

Using __test_and_{set,clear}_bit_le() with ignoring its return value can
be replaced with __{set,clear}_bit_le().

This introduces reiserfs_{set,clear}_le_bit for __{set,clear}_bit_le and
does the above change with them.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

As a preparation for removing ext2 non-atomic bit operations from
asm/bitops.h.  This converts ext2 non-atomic bit operations to
little-endian bit operations.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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>

__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>

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

Fix trivial typo in code comment (change adn for and), also change comment
style for proper coding style.
Signed-off-by: NDavidlohr Bueso <dave@gnu.org>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

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>

When we relax the reiserfs lock to avoid creating unwanted
dependencies against others locks while grabbing these,
we want to ensure it has not been taken recursively, otherwise
the lock won't be really relaxed. Only its depth will be decreased.
The unwanted dependency would then actually happen.

To prevent from that, add a reiserfs_lock_check_recursive() call
in the places that need it.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>

i_xattr_sem depends on the reiserfs lock. But after we grab
i_xattr_sem, we may relax/relock the reiserfs lock while waiting
on a freezed filesystem, creating a dependency inversion between
the two locks.

In order to avoid the i_xattr_sem -> reiserfs lock dependency, let's
create a reiserfs_down_read_safe() that acts like
reiserfs_mutex_lock_safe(): relax the reiserfs lock while grabbing
another lock to avoid undesired dependencies induced by the
heivyweight reiserfs lock.

This fixes the following warning:

[  990.005931] =======================================================
[  990.012373] [ INFO: possible circular locking dependency detected ]
[  990.013233] 2.6.33-rc1 #1
[  990.013233] -------------------------------------------------------
[  990.013233] dbench/1891 is trying to acquire lock:
[  990.013233]  (&REISERFS_SB(s)->lock){+.+.+.}, at: [<ffffffff81159505>] reiserfs_write_lock+0x35/0x50
[  990.013233]
[  990.013233] but task is already holding lock:
[  990.013233]  (&REISERFS_I(inode)->i_xattr_sem){+.+.+.}, at: [<ffffffff8115899a>] reiserfs_xattr_set_handle+0x8a/0x470
[  990.013233]
[  990.013233] which lock already depends on the new lock.
[  990.013233]
[  990.013233]
[  990.013233] the existing dependency chain (in reverse order) is:
[  990.013233]
[  990.013233] -> #1 (&REISERFS_I(inode)->i_xattr_sem){+.+.+.}:
[  990.013233]        [<ffffffff81063afc>] __lock_acquire+0xf9c/0x1560
[  990.013233]        [<ffffffff8106414f>] lock_acquire+0x8f/0xb0
[  990.013233]        [<ffffffff814ac194>] down_write+0x44/0x80
[  990.013233]        [<ffffffff8115899a>] reiserfs_xattr_set_handle+0x8a/0x470
[  990.013233]        [<ffffffff81158e30>] reiserfs_xattr_set+0xb0/0x150
[  990.013233]        [<ffffffff8115a6aa>] user_set+0x8a/0x90
[  990.013233]        [<ffffffff8115901a>] reiserfs_setxattr+0xaa/0xb0
[  990.013233]        [<ffffffff810e2596>] __vfs_setxattr_noperm+0x36/0xa0
[  990.013233]        [<ffffffff810e26bc>] vfs_setxattr+0xbc/0xc0
[  990.013233]        [<ffffffff810e2780>] setxattr+0xc0/0x150
[  990.013233]        [<ffffffff810e289d>] sys_fsetxattr+0x8d/0xa0
[  990.013233]        [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
[  990.013233]
[  990.013233] -> #0 (&REISERFS_SB(s)->lock){+.+.+.}:
[  990.013233]        [<ffffffff81063e30>] __lock_acquire+0x12d0/0x1560
[  990.013233]        [<ffffffff8106414f>] lock_acquire+0x8f/0xb0
[  990.013233]        [<ffffffff814aba77>] __mutex_lock_common+0x47/0x3b0
[  990.013233]        [<ffffffff814abebe>] mutex_lock_nested+0x3e/0x50
[  990.013233]        [<ffffffff81159505>] reiserfs_write_lock+0x35/0x50
[  990.013233]        [<ffffffff811340e5>] reiserfs_prepare_write+0x45/0x180
[  990.013233]        [<ffffffff81158bb6>] reiserfs_xattr_set_handle+0x2a6/0x470
[  990.013233]        [<ffffffff81158e30>] reiserfs_xattr_set+0xb0/0x150
[  990.013233]        [<ffffffff8115a6aa>] user_set+0x8a/0x90
[  990.013233]        [<ffffffff8115901a>] reiserfs_setxattr+0xaa/0xb0
[  990.013233]        [<ffffffff810e2596>] __vfs_setxattr_noperm+0x36/0xa0
[  990.013233]        [<ffffffff810e26bc>] vfs_setxattr+0xbc/0xc0
[  990.013233]        [<ffffffff810e2780>] setxattr+0xc0/0x150
[  990.013233]        [<ffffffff810e289d>] sys_fsetxattr+0x8d/0xa0
[  990.013233]        [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
[  990.013233]
[  990.013233] other info that might help us debug this:
[  990.013233]
[  990.013233] 2 locks held by dbench/1891:
[  990.013233]  #0:  (&sb->s_type->i_mutex_key#12){+.+.+.}, at: [<ffffffff810e2678>] vfs_setxattr+0x78/0xc0
[  990.013233]  #1:  (&REISERFS_I(inode)->i_xattr_sem){+.+.+.}, at: [<ffffffff8115899a>] reiserfs_xattr_set_handle+0x8a/0x470
[  990.013233]
[  990.013233] stack backtrace:
[  990.013233] Pid: 1891, comm: dbench Not tainted 2.6.33-rc1 #1
[  990.013233] Call Trace:
[  990.013233]  [<ffffffff81061639>] print_circular_bug+0xe9/0xf0
[  990.013233]  [<ffffffff81063e30>] __lock_acquire+0x12d0/0x1560
[  990.013233]  [<ffffffff8115899a>] ? reiserfs_xattr_set_handle+0x8a/0x470
[  990.013233]  [<ffffffff8106414f>] lock_acquire+0x8f/0xb0
[  990.013233]  [<ffffffff81159505>] ? reiserfs_write_lock+0x35/0x50
[  990.013233]  [<ffffffff8115899a>] ? reiserfs_xattr_set_handle+0x8a/0x470
[  990.013233]  [<ffffffff814aba77>] __mutex_lock_common+0x47/0x3b0
[  990.013233]  [<ffffffff81159505>] ? reiserfs_write_lock+0x35/0x50
[  990.013233]  [<ffffffff81159505>] ? reiserfs_write_lock+0x35/0x50
[  990.013233]  [<ffffffff81062592>] ? mark_held_locks+0x72/0xa0
[  990.013233]  [<ffffffff814ab81d>] ? __mutex_unlock_slowpath+0xbd/0x140
[  990.013233]  [<ffffffff810628ad>] ? trace_hardirqs_on_caller+0x14d/0x1a0
[  990.013233]  [<ffffffff814abebe>] mutex_lock_nested+0x3e/0x50
[  990.013233]  [<ffffffff81159505>] reiserfs_write_lock+0x35/0x50
[  990.013233]  [<ffffffff811340e5>] reiserfs_prepare_write+0x45/0x180
[  990.013233]  [<ffffffff81158bb6>] reiserfs_xattr_set_handle+0x2a6/0x470
[  990.013233]  [<ffffffff81158e30>] reiserfs_xattr_set+0xb0/0x150
[  990.013233]  [<ffffffff814abcb4>] ? __mutex_lock_common+0x284/0x3b0
[  990.013233]  [<ffffffff8115a6aa>] user_set+0x8a/0x90
[  990.013233]  [<ffffffff8115901a>] reiserfs_setxattr+0xaa/0xb0
[  990.013233]  [<ffffffff810e2596>] __vfs_setxattr_noperm+0x36/0xa0
[  990.013233]  [<ffffffff810e26bc>] vfs_setxattr+0xbc/0xc0
[  990.013233]  [<ffffffff810e2780>] setxattr+0xc0/0x150
[  990.013233]  [<ffffffff81056018>] ? sched_clock_cpu+0xb8/0x100
[  990.013233]  [<ffffffff8105eded>] ? trace_hardirqs_off+0xd/0x10
[  990.013233]  [<ffffffff810560a3>] ? cpu_clock+0x43/0x50
[  990.013233]  [<ffffffff810c6820>] ? fget+0xb0/0x110
[  990.013233]  [<ffffffff810c6770>] ? fget+0x0/0x110
[  990.013233]  [<ffffffff81002ddc>] ? sysret_check+0x27/0x62
[  990.013233]  [<ffffffff810e289d>] sys_fsetxattr+0x8d/0xa0
[  990.013233]  [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
Reported-and-tested-by: NChristian Kujau <lists@nerdbynature.de>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>

The reiserfs lock -> inode mutex dependency gets inverted when we
relax the lock while walking to the tree.

To fix this, use a specialized version of reiserfs_mutex_lock_safe
that takes care of mutex subclasses. Then we can grab the inode
mutex with I_MUTEX_XATTR subclass without any reiserfs lock
dependency.

This fixes the following report:

[ INFO: possible circular locking dependency detected ]
2.6.32-06793-gf4054253-dirty #2
-------------------------------------------------------
mv/18566 is trying to acquire lock:
 (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c1110708>] reiserfs_write_lock+0x28=
/0x40

but task is already holding lock:
 (&sb->s_type->i_mutex_key#5/3){+.+.+.}, at: [<c111033c>]
reiserfs_for_each_xattr+0x10c/0x380

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&sb->s_type->i_mutex_key#5/3){+.+.+.}:
       [<c104f723>] validate_chain+0xa23/0xf70
       [<c1050155>] __lock_acquire+0x4e5/0xa70
       [<c105075a>] lock_acquire+0x7a/0xa0
       [<c134c76f>] mutex_lock_nested+0x5f/0x2b0
       [<c11102b4>] reiserfs_for_each_xattr+0x84/0x380
       [<c1110615>] reiserfs_delete_xattrs+0x15/0x50
       [<c10ef57f>] reiserfs_delete_inode+0x8f/0x140
       [<c10a565c>] generic_delete_inode+0x9c/0x150
       [<c10a574d>] generic_drop_inode+0x3d/0x60
       [<c10a4667>] iput+0x47/0x50
       [<c109cc0b>] do_unlinkat+0xdb/0x160
       [<c109cca0>] sys_unlink+0x10/0x20
       [<c1002c50>] sysenter_do_call+0x12/0x36

-> #0 (&REISERFS_SB(s)->lock){+.+.+.}:
       [<c104fc68>] validate_chain+0xf68/0xf70
       [<c1050155>] __lock_acquire+0x4e5/0xa70
       [<c105075a>] lock_acquire+0x7a/0xa0
       [<c134c76f>] mutex_lock_nested+0x5f/0x2b0
       [<c1110708>] reiserfs_write_lock+0x28/0x40
       [<c1103d6b>] search_by_key+0x1f7b/0x21b0
       [<c10e73ef>] search_by_entry_key+0x1f/0x3b0
       [<c10e77f7>] reiserfs_find_entry+0x77/0x400
       [<c10e81e5>] reiserfs_lookup+0x85/0x130
       [<c109a144>] __lookup_hash+0xb4/0x110
       [<c109b763>] lookup_one_len+0xb3/0x100
       [<c1110350>] reiserfs_for_each_xattr+0x120/0x380
       [<c1110615>] reiserfs_delete_xattrs+0x15/0x50
       [<c10ef57f>] reiserfs_delete_inode+0x8f/0x140
       [<c10a565c>] generic_delete_inode+0x9c/0x150
       [<c10a574d>] generic_drop_inode+0x3d/0x60
       [<c10a4667>] iput+0x47/0x50
       [<c10a1c4f>] dentry_iput+0x6f/0xf0
       [<c10a1d74>] d_kill+0x24/0x50
       [<c10a396b>] dput+0x5b/0x120
       [<c109ca89>] sys_renameat+0x1b9/0x230
       [<c109cb28>] sys_rename+0x28/0x30
       [<c1002c50>] sysenter_do_call+0x12/0x36

other info that might help us debug this:

2 locks held by mv/18566:
 #0:  (&sb->s_type->i_mutex_key#5/1){+.+.+.}, at: [<c109b6ac>]
lock_rename+0xcc/0xd0
 #1:  (&sb->s_type->i_mutex_key#5/3){+.+.+.}, at: [<c111033c>]
reiserfs_for_each_xattr+0x10c/0x380

stack backtrace:
Pid: 18566, comm: mv Tainted: G         C 2.6.32-06793-gf4054253-dirty #2
Call Trace:
 [<c134b252>] ? printk+0x18/0x1e
 [<c104e790>] print_circular_bug+0xc0/0xd0
 [<c104fc68>] validate_chain+0xf68/0xf70
 [<c104c8cb>] ? trace_hardirqs_off+0xb/0x10
 [<c1050155>] __lock_acquire+0x4e5/0xa70
 [<c105075a>] lock_acquire+0x7a/0xa0
 [<c1110708>] ? reiserfs_write_lock+0x28/0x40
 [<c134c76f>] mutex_lock_nested+0x5f/0x2b0
 [<c1110708>] ? reiserfs_write_lock+0x28/0x40
 [<c1110708>] ? reiserfs_write_lock+0x28/0x40
 [<c134b60a>] ? schedule+0x27a/0x440
 [<c1110708>] reiserfs_write_lock+0x28/0x40
 [<c1103d6b>] search_by_key+0x1f7b/0x21b0
 [<c1050176>] ? __lock_acquire+0x506/0xa70
 [<c1051267>] ? lock_release_non_nested+0x1e7/0x340
 [<c1110708>] ? reiserfs_write_lock+0x28/0x40
 [<c104e354>] ? trace_hardirqs_on_caller+0x124/0x170
 [<c104e3ab>] ? trace_hardirqs_on+0xb/0x10
 [<c1042a55>] ? T.316+0x15/0x1a0
 [<c1042d2d>] ? sched_clock_cpu+0x9d/0x100
 [<c10e73ef>] search_by_entry_key+0x1f/0x3b0
 [<c134bf2a>] ? __mutex_unlock_slowpath+0x9a/0x120
 [<c104e354>] ? trace_hardirqs_on_caller+0x124/0x170
 [<c10e77f7>] reiserfs_find_entry+0x77/0x400
 [<c10e81e5>] reiserfs_lookup+0x85/0x130
 [<c1042d2d>] ? sched_clock_cpu+0x9d/0x100
 [<c109a144>] __lookup_hash+0xb4/0x110
 [<c109b763>] lookup_one_len+0xb3/0x100
 [<c1110350>] reiserfs_for_each_xattr+0x120/0x380
 [<c110ffe0>] ? delete_one_xattr+0x0/0x1c0
 [<c1003342>] ? math_error+0x22/0x150
 [<c1110708>] ? reiserfs_write_lock+0x28/0x40
 [<c1110615>] reiserfs_delete_xattrs+0x15/0x50
 [<c1110708>] ? reiserfs_write_lock+0x28/0x40
 [<c10ef57f>] reiserfs_delete_inode+0x8f/0x140
 [<c10a561f>] ? generic_delete_inode+0x5f/0x150
 [<c10ef4f0>] ? reiserfs_delete_inode+0x0/0x140
 [<c10a565c>] generic_delete_inode+0x9c/0x150
 [<c10a574d>] generic_drop_inode+0x3d/0x60
 [<c10a4667>] iput+0x47/0x50
 [<c10a1c4f>] dentry_iput+0x6f/0xf0
 [<c10a1d74>] d_kill+0x24/0x50
 [<c10a396b>] dput+0x5b/0x120
 [<c109ca89>] sys_renameat+0x1b9/0x230
 [<c1042d2d>] ? sched_clock_cpu+0x9d/0x100
 [<c104c8cb>] ? trace_hardirqs_off+0xb/0x10
 [<c1042dde>] ? cpu_clock+0x4e/0x60
 [<c1350825>] ? do_page_fault+0x155/0x370
 [<c1041816>] ? up_read+0x16/0x30
 [<c1350825>] ? do_page_fault+0x155/0x370
 [<c109cb28>] sys_rename+0x28/0x30
 [<c1002c50>] sysenter_do_call+0x12/0x36
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>

* small define cleanup in header
* fix #ifdeffery in procfs.c via Kconfig
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

/proc/fs/reiserfs/version is on the way of removing ->read_proc interface.
 It's empty however, so simply remove it instead of doing dummy
conversion.  It's hard to see what information userspace can extract from
empty file.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The reiserfs ioctl path doesn't need the big kernel lock anymore , now
that the filesystem synchronizes through its own lock.

We can then turn reiserfs_ioctl() into an unlocked_ioctl callback.
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>

While searching a pathname, an inode mutex can be acquired
in do_lookup() which calls reiserfs_lookup() which in turn
acquires the write lock.

On the other side reiserfs_fill_super() can acquire the write_lock
and then call reiserfs_lookup_privroot() which can acquire an
inode mutex (the root of the mount point).

So we theoretically risk an AB - BA lock inversion that could lead
to a deadlock.

As for other lock dependencies found since the bkl to mutex
conversion, the fix is to use reiserfs_mutex_lock_safe() which
drops the lock dependency to the write lock.

[ Impact: fix a possible deadlock with reiserfs ]

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>

The goal of fs_changed() is to check whether the tree changed during a
schedule(). This is a BKL legacy.

A recent patch added an explicit unconditional release/reacquire of the
write lock around the cond_resched() called inside fs_changed.

But it's wasteful to unconditionally do that, we are creating superfluous
lock contention in !TIF_NEED_RESCHED case.

This patch manage that by calling reiserfs_cond_resched() from fs_changed()
which only releases the lock if we are going to reschedule.

[ Impact: inject less lock contention and tree job retries ]

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>

Usually, when we call cond_resched(), we want the write lock
to be released and then reacquired once we return from scheduling.
Not only does it follow the previous bkl based locking scheme, but
it also let other waiters to get the lock.

But if we aren't going to reschedule(), such as in !TIF_NEED_RESCHED
case, it's useless to release the lock. Worse, if we release and reacquire
the lock whereas it is not needed, we create useless contentions. Also
if someone takes the lock while we are modifying or reading the tree,
there are good chances we'll have to retry our operation, eg if the
block we were seeeking has moved.

So this patch introduces a helper which only unlock the write lock
if we are going to schedule.

[ Impact: prepare to inject less lock contention and less tree operation attempts ]
Reported-by: NAndi Kleen <andi@firstfloor.org>
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>

fs_changed() is a macro used by reiserfs to check whether its tree has been
rebalanced. It has been designed to check parallel changes on the tree after
calling a sleeping function, which released the Bkl.

fs_changed() also calls cond_resched(), so that if rescheduling is needed,
we are in the best place to do that, since we check if the tree has changed
just after (because of the bkl release on schedule()).

Even if we are not anymore using the Bkl, we still want to release the lock
while we reschedule, so that other waiters for the lock can acquire it safely,
because of the following __fs_changed() check.

[ Impact: release the reiserfs write lock when it is not needed ]

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

Sometimes we don't want to recursively hold the per superblock write
lock because we want to be sure it is actually released when we come
to sleep.

This patch introduces the necessary tools for that.

reiserfs_write_lock_once() does the same job than reiserfs_write_lock()
except that it won't try to acquire recursively the lock if the current
task already owns it. Also the lock_depth before the call of this function
is returned.

reiserfs_write_unlock_once() unlock only if reiserfs_write_lock_once()
returned a depth equal to -1, ie: only if it actually locked.
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: <1239680065-25013-2-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>

Several code paths in reiserfs have a construct like:

 if (is_direntry_le_ih(ih = B_N_PITEM_HEAD(src, item_num))) ...

which, in addition to being ugly, end up causing compiler warnings with
gcc 4.4.0.  Previous compilers didn't issue a warning.

fs/reiserfs/do_balan.c:1273: warning: operation on `aux_ih' may be undefined
fs/reiserfs/lbalance.c:393: warning: operation on `ih' may be undefined
fs/reiserfs/lbalance.c:421: warning: operation on `ih' may be undefined
fs/reiserfs/lbalance.c:777: warning: operation on `ih' may be undefined

I believe this is due to the ih being passed to macros which evaluate the
argument more than once.  This is old code and we haven't seen any
problems with it, but this patch eliminates the warnings.

It converts the multiple evaluation macros to static inlines and does a
preassignment for the cases that were causing the warnings because that
code is just ugly.
Reported-by: NChris Mason <mason@oracle.com>
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch is a simple s/p_._//g to the reiserfs code.  This is the
fifth 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 is a simple s/p_s_tb/tb/g to the reiserfs code.  This is the
fourth 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 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 is a simple s/p_s_bh/bh/g to the reiserfs code.  This is the
second 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 is a simple s/p_s_sb/sb/g to the reiserfs code.  This is the
first 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>

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>

The current reiserfs xattr implementation open codes reiserfs_readdir
and frees the path before calling the filldir function.  Typically, the
filldir function is something that modifies the file system, such as a
chown or an inode deletion that also require reading of an inode
associated with each direntry.  Since the file system is modified, the
path retained becomes invalid for the next run.  In addition, it runs
backwards in attempt to minimize activity.

This is clearly suboptimal from a code cleanliness perspective as well
as performance-wise.

This patch implements a generic reiserfs_for_each_xattr that uses the
generic readdir and a specific filldir routine that simply populates an
array of dentries and then performs a specific operation on them.  When
all files have been operated on, it then calls the operation on the
directory itself.

The result is a noticable code reduction and better performance.
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>