will get rid of nilfs_get_writer() and nilfs_put_writer() pair used to
retain a writable FS-instance for a period.

The pair functions were making up some kind of recursive lock with a
mutex, but they became overkill since the commit
201913ed.  Furthermore, they caused
the following lockdep warning because the mutex can be released by a
task which didn't lock it:

 =====================================
 [ BUG: bad unlock balance detected! ]
 -------------------------------------
 kswapd0/422 is trying to release lock (&nilfs->ns_writer_mutex) at:
 [<c1359ff5>] mutex_unlock+0x8/0xa
 but there are no more locks to release!

 other info that might help us debug this:
 no locks held by kswapd0/422.

 stack backtrace:
 Pid: 422, comm: kswapd0 Not tainted 2.6.31-rc4-nilfs #51
 Call Trace:
  [<c1358f97>] ? printk+0xf/0x18
  [<c104fea7>] print_unlock_inbalance_bug+0xcc/0xd7
  [<c11578de>] ? prop_put_global+0x3/0x35
  [<c1050195>] lock_release+0xed/0x1dc
  [<c1359ff5>] ? mutex_unlock+0x8/0xa
  [<c1359f83>] __mutex_unlock_slowpath+0xaf/0x119
  [<c1359ff5>] mutex_unlock+0x8/0xa
  [<d1284add>] nilfs_mdt_write_page+0xd8/0xe1 [nilfs2]
  [<c1092653>] shrink_page_list+0x379/0x68d
  [<c109171b>] ? isolate_pages_global+0xb4/0x18c
  [<c1092bd2>] shrink_list+0x26b/0x54b
  [<c10930be>] shrink_zone+0x20c/0x2a2
  [<c10936b7>] kswapd+0x407/0x591
  [<c1091667>] ? isolate_pages_global+0x0/0x18c
  [<c1040603>] ? autoremove_wake_function+0x0/0x33
  [<c10932b0>] ? kswapd+0x0/0x591
  [<c104033b>] kthread+0x69/0x6e
  [<c10402d2>] ? kthread+0x0/0x6e
  [<c1003e33>] kernel_thread_helper+0x7/0x1a

This patch uses a reader/writer semaphore instead of the own lock and
kills this warning.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Unlike on most other architectures ino_t is an unsigned int on s390.
So add an explicit cast to avoid this compile warning:

fs/nilfs2/recovery.c: In function 'recover_dsync_blocks':
fs/nilfs2/recovery.c:555: warning: format '%lu' expects type 'long unsigned int', but argument 3 has type 'ino_t'
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

The __nilfs_read_inode function is ignoring the error code returned
from nilfs_read_inode_common(), and wrongly delivers a success code
(zero) when it escapes from the function in erroneous cases.

This adds the missing error handling.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This will fix the following preempt count underflow reported from
users with the title "[NILFS users] segctord problem" (Message-ID:
<949415.6494.qm@web58808.mail.re1.yahoo.com> and Message-ID:
<debc30fc0908270825v747c1734xa59126623cfd5b05@mail.gmail.com>):

 WARNING: at kernel/sched.c:4890 sub_preempt_count+0x95/0xa0()
 Hardware name: HP Compaq 6530b (KR980UT#ABC)
 Modules linked in: bridge stp llc bnep rfcomm l2cap xfs exportfs nilfs2 cowloop loop vboxnetadp vboxnetflt vboxdrv btusb bluetooth uvcvideo videodev v4l1_compat v4l2_compat_ioctl32 arc4 snd_hda_codec_analog ecb iwlagn iwlcore rfkill lib80211 mac80211 snd_hda_intel snd_hda_codec ehci_hcd uhci_hcd usbcore snd_hwdep snd_pcm tg3 cfg80211 psmouse snd_timer joydev libphy ohci1394 snd_page_alloc hp_accel lis3lv02d ieee1394 led_class i915 drm i2c_algo_bit video backlight output i2c_core dm_crypt dm_mod
 Pid: 4197, comm: segctord Not tainted 2.6.30-gentoo-r4-64 #7
 Call Trace:
  [<ffffffff8023fa05>] ? sub_preempt_count+0x95/0xa0
  [<ffffffff802470f8>] warn_slowpath_common+0x78/0xd0
  [<ffffffff8024715f>] warn_slowpath_null+0xf/0x20
  [<ffffffff8023fa05>] sub_preempt_count+0x95/0xa0
  [<ffffffffa04ce4db>] nilfs_btnode_prepare_change_key+0x11b/0x190 [nilfs2]
  [<ffffffffa04d01ad>] nilfs_btree_assign_p+0x19d/0x1e0 [nilfs2]
  [<ffffffffa04d10ad>] nilfs_btree_assign+0xbd/0x130 [nilfs2]
  [<ffffffffa04cead7>] nilfs_bmap_assign+0x47/0x70 [nilfs2]
  [<ffffffffa04d9bc6>] nilfs_segctor_do_construct+0x956/0x20f0 [nilfs2]
  [<ffffffff805ac8e2>] ? _spin_unlock_irqrestore+0x12/0x40
  [<ffffffff803c06e0>] ? __up_write+0xe0/0x150
  [<ffffffff80262959>] ? up_write+0x9/0x10
  [<ffffffffa04ce9f3>] ? nilfs_bmap_test_and_clear_dirty+0x43/0x60 [nilfs2]
  [<ffffffffa04cd627>] ? nilfs_mdt_fetch_dirty+0x27/0x60 [nilfs2]
  [<ffffffffa04db5fc>] nilfs_segctor_construct+0x8c/0xd0 [nilfs2]
  [<ffffffffa04dc3dc>] nilfs_segctor_thread+0x15c/0x3a0 [nilfs2]
  [<ffffffffa04dbe20>] ? nilfs_construction_timeout+0x0/0x10 [nilfs2]
  [<ffffffff80252633>] ? add_timer+0x13/0x20
  [<ffffffff802370da>] ? __wake_up_common+0x5a/0x90
  [<ffffffff8025e960>] ? autoremove_wake_function+0x0/0x40
  [<ffffffffa04dc280>] ? nilfs_segctor_thread+0x0/0x3a0 [nilfs2]
  [<ffffffffa04dc280>] ? nilfs_segctor_thread+0x0/0x3a0 [nilfs2]
  [<ffffffff8025e556>] kthread+0x56/0x90
  [<ffffffff8020cdea>] child_rip+0xa/0x20
  [<ffffffff8025e500>] ? kthread+0x0/0x90
  [<ffffffff8020cde0>] ? child_rip+0x0/0x20

This problem was caused due to a missing radix_tree_preload() call in
the retry path of nilfs_btnode_prepare_change_key() function.
Reported-by: NEric A <eric225125@yahoo.com>
Reported-by: NJerome Poulin <jeromepoulin@gmail.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: NJerome Poulin <jeromepoulin@gmail.com>
Cc: stable@kernel.org

will fix kernel oopses like the following:

 # mount -t nilfs2 -r -o cp=20 /dev/sdb1 /test1
 # mount -t nilfs2 -r -o cp=20 /dev/sdb1 /test2
 # umount /test1
 # umount /test2

BUG: sleeping function called from invalid context at arch/x86/mm/fault.c:1069
in_atomic(): 0, irqs_disabled(): 1, pid: 3886, name: umount.nilfs2
1 lock held by umount.nilfs2/3886:
 #0:  (&type->s_umount_key#31){+.+...}, at: [<c10b398a>] deactivate_super+0x52/0x6c
irq event stamp: 1219
hardirqs last  enabled at (1219): [<c135c774>] __mutex_unlock_slowpath+0xf8/0x119
hardirqs last disabled at (1218): [<c135c6d5>] __mutex_unlock_slowpath+0x59/0x119
softirqs last  enabled at (1214): [<c1033316>] __do_softirq+0x1a5/0x1ad
softirqs last disabled at (1205): [<c1033354>] do_softirq+0x36/0x5a
Pid: 3886, comm: umount.nilfs2 Not tainted 2.6.31-rc6 #55
Call Trace:
 [<c1023549>] __might_sleep+0x107/0x10e
 [<c13603c0>] do_page_fault+0x246/0x397
 [<c136017a>] ? do_page_fault+0x0/0x397
 [<c135e753>] error_code+0x6b/0x70
 [<c136017a>] ? do_page_fault+0x0/0x397
 [<c104f805>] ? __lock_acquire+0x91/0x12fd
 [<c1050a62>] ? __lock_acquire+0x12ee/0x12fd
 [<c1050a62>] ? __lock_acquire+0x12ee/0x12fd
 [<c1050b2b>] lock_acquire+0xba/0xdd
 [<d0d17d3f>] ? nilfs_detach_segment_constructor+0x2f/0x2fa [nilfs2]
 [<c135d4fe>] down_write+0x2a/0x46
 [<d0d17d3f>] ? nilfs_detach_segment_constructor+0x2f/0x2fa [nilfs2]
 [<d0d17d3f>] nilfs_detach_segment_constructor+0x2f/0x2fa [nilfs2]
 [<c104ea2c>] ? mark_held_locks+0x43/0x5b
 [<c104ecb1>] ? trace_hardirqs_on_caller+0x10b/0x133
 [<c104ece4>] ? trace_hardirqs_on+0xb/0xd
 [<d0d09ac1>] nilfs_put_super+0x2f/0xca [nilfs2]
 [<c10b3352>] generic_shutdown_super+0x49/0xb8
 [<c10b33de>] kill_block_super+0x1d/0x31
 [<c10e6599>] ? vfs_quota_off+0x0/0x12
 [<c10b398f>] deactivate_super+0x57/0x6c
 [<c10c4bc3>] mntput_no_expire+0x8c/0xb4
 [<c10c5094>] sys_umount+0x27f/0x2a4
 [<c10c50c6>] sys_oldumount+0xd/0xf
 [<c10031a4>] sysenter_do_call+0x12/0x38
 ...

This turns out to be a bug brought by an -rc1 patch ("nilfs2: simplify
remaining sget() use").

In the patch, a new "put resource" function, nilfs_put_sbinfo()
was introduced to delay freeing nilfs_sb_info struct.

But the nilfs_put_sbinfo() mistakenly used atomic_dec_and_test()
function to check the reference count, and it caused the nilfs_sb_info
was freed when user mounted a snapshot twice.

This bug also suggests there was unseen memory leak in usual mount
/umount operations for nilfs.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

'ns_cno' of structure 'the_nilfs' must be protected from segment
writer, in other words, the caller of nilfs_get_checkpoint should hold
read lock for nilfs->ns_segctor_sem.  This patch adds the lock/unlock
operations in nilfs_attach_checkpoint() when calling
nilfs_cpfile_get_checkpoint().
Signed-off-by: NZhang Qiang <zhangqiang.buaa@gmail.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This adds a missing unlock of nilfs->ns_writer_mutex in
nilfs_mdt_write_page() function.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Andrea Gelmini gave me a report that a kernel oops hit on a nilfs
filesystem with a 1KB block size when doing rsync.

This turned out to be caused by an inconsistency of dirty state
between a page and its buffers storing b-tree node blocks.

If the page had multiple buffers split over multiple logs, and if the
logs were written at a time, a dirty flag remained in the page even
every dirty flag in the buffers was cleared.

This will fix the failure by dropping the dirty flag properly for
pages with the discrete multiple b-tree nodes.
Reported-by: NAndrea Gelmini <andrea.gelmini@gmail.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: NAndrea Gelmini <andrea.gelmini@gmail.com>
Cc: stable@kernel.org

fs/Kconfig file was split into individual fs/*/Kconfig files before
nilfs was merged.  I've found the current config entry of nilfs is
tainting the work.  Sorry, I didn't notice.  This fixes the violation.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Alexey Dobriyan <adobriyan@gmail.com>

* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
  It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT

  This will make hardirq.h inclusion cheaper for every PREEMPT=n config
  (which includes allmodconfig/allyesconfig, BTW)
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This fixes a bug that checkpoint count gets wrong on errors when
deleting a series of checkpoints.

The count error is persistent since the checkpoint count is stored on
disk.  Some userland programs refer to the count via ioctl, and this
bugfix is needed to prevent malfunction of such programs.
Signed-off-by: NJiro SEKIBA <jir@unicus.jp>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: stable@kernel.org

This will fix the following false positive of recursive locking which
lockdep has detected:

=============================================
[ INFO: possible recursive locking detected ]
2.6.30-nilfs #42
---------------------------------------------
nilfs_cleanerd/10607 is trying to acquire lock:
 (&bmap->b_sem){++++-.}, at: [<e0d025b7>] nilfs_bmap_lookup_at_level+0x1a/0x74 [nilfs2]

but task is already holding lock:
 (&bmap->b_sem){++++-.}, at: [<e0d024e0>] nilfs_bmap_truncate+0x19/0x6a [nilfs2]
other info that might help us debug this:
2 locks held by nilfs_cleanerd/10607:
 #0:  (&nilfs->ns_segctor_sem){++++.+}, at: [<e0d0d75a>] nilfs_transaction_begin+0xb6/0x10c [nilfs2]
 #1:  (&bmap->b_sem){++++-.}, at: [<e0d024e0>] nilfs_bmap_truncate+0x19/0x6a [nilfs2]
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

In case of write-failure retries, the following KERN_CRIT level
messages are mistakenly output by nilfs_dat_commit_start() function:

nilfs_dat_commit_start: vbn = 408463, start = 12506, end = 18446744073709551615, pbn = 530210
nilfs_dat_commit_start: vbn = 408515, start = 12506, end = 18446744073709551615, pbn = 530211
nilfs_dat_commit_start: vbn = 408464, start = 12506, end = 18446744073709551615, pbn = 530212
...

This suppresses these messages.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: stable@kernel.org

Leandro Lucarella gave me a report that nilfs gets stuck after its
write function fails.

The problem turned out to be caused by bugs which leave writeback flag
on pages.  This fixes the problem by ensuring to clear the writeback
flag in error path.
Reported-by: NLeandro Lucarella <llucax@gmail.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: stable@kernel.org

The following error code handling in nilfs_segctor_write() function
wrongly converted negative error codes to a truth value (i.e. 1):

   err = unlikely(err) ? : res;

which originaly meant to be

   err = err ? : res;

This mis-conversion caused that write or sync functions receive the
unexpected error code.  This fixes the bug by removing the unlikely
directive.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: stable@kernel.org

Actually, get rid of private analog, since nothing in there is
using ACLs at all so far.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This will remove every bd_mount_sem use in nilfs.

The intended exclusion control was replaced by the previous patch
("nilfs2: correct exclusion control in nilfs_remount function") for
nilfs_remount(), and this patch will replace remains with a new mutex
that this inserts in nilfs object.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

nilfs_remount() changes mount state of a superblock instance.  Even
though nilfs accesses other superblock instances during mount or
remount, the mount state was not properly protected in
nilfs_remount().

Moreover, nilfs_remount() has a lock order reversal problem;
nilfs_get_sb() holds:

  1. bdev->bd_mount_sem
  2. sb->s_umount  (sget acquires)

and nilfs_remount() holds:

  1. sb->s_umount  (locked by the caller in vfs)
  2. bdev->bd_mount_sem

To avoid these problems, this patch divides a semaphore protecting
super block instances from nilfs->ns_sem, and applies it to the mount
state protection in nilfs_remount().

With this change, bd_mount_sem use is removed from nilfs_remount() and
the lock order reversal will be resolved.  And the new rw-semaphore,
nilfs->ns_super_sem will properly protect the mount state except the
modification from nilfs_error function.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This simplifies the test function passed on the remaining sget()
callsite in nilfs.

Instead of checking mount type (i.e. ro-mount/rw-mount/snapshot mount)
in the test function passed to sget(), this patch first looks up the
nilfs_sb_info struct which the given mount type matches, and then
acquires the super block instance holding the nilfs_sb_info.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This stops using sget() for checking if an r/w-mount or an r/o-mount
exists on the device.  This elimination uses a back pointer to the
current mount added to nilfs object.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This will change the way to obtain nilfs object in nilfs_get_sb()
function.

Previously, a preliminary sget() call was performed, and the nilfs
object was acquired from a super block instance found by the sget()
call.

This patch, instead, instroduces a new dedicated function
find_or_create_nilfs(); as the name implies, the function finds an
existent nilfs object from a global list or creates a new one if no
object is found on the device.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The following EBUSY case in nilfs_get_sb() is meaningless.  Indeed,
this error code is never returned to the caller.

    if (!s->s_root) {
          ...
    } else if (!(s->s_flags & MS_RDONLY)) {
        err = -EBUSY;
    }

This simply removes the else case.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The call to ->write_super from __sync_filesystem will go away, so make
sure nilfs2 performs the same actions from inside ->sync_fs.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

[xfs, btrfs, capifs, shmem don't need BKL, exempt]
Signed-off-by: NAlessio Igor Bogani <abogani@texware.it>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Move BKL into ->put_super from the only caller.  A couple of
filesystems had trivial enough ->put_super (only kfree and NULLing of
s_fs_info + stuff in there) to not get any locking: coda, cramfs, efs,
hugetlbfs, omfs, qnx4, shmem, all others got the full treatment.  Most
of them probably don't need it, but I'd rather sort that out individually.
Preferably after all the other BKL pushdowns in that area.

[AV: original used to move lock_super() down as well; these changes are
removed since we don't do lock_super() at all in generic_shutdown_super()
now]
[AV: fuse, btrfs and xfs are known to need no damn BKL, exempt]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We just did a full fs writeout using sync_filesystem before, and if
that's not enough for the filesystem it can perform it's own writeout
in ->put_super, which many filesystems already do.

Move a call to foofs_write_super into every foofs_put_super for now to
guarantee identical behaviour until it's cleaned up by the individual
filesystem maintainers.

Exceptions:

 - affs already has identical copy & pasted code at the beginning of
   affs_put_super so no need to do it twice.
 - xfs does the right thing without it and I have changes pending for
   the xfs tree touching this are so I don't really need conflicts
   here..
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Although get_block() callback function can return extent of contiguous
blocks with bh->b_size, nilfs_get_block() function did not support
this feature.

This adds contiguous lookup feature to the block mapping codes of
nilfs, and allows the nilfs_get_blocks() function to return the extent
information by applying the feature.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This applies block_sync_page() function to the sync_page method of
page caches for meta data files, gc page caches, and btree node
buffers.  This is a companion patch of ("nilfs2: enable sync_page
mothod") which applied the function for data pages.

This allows lock_page() for those meta data to unplug pending bio
requests.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Previously, default_backing_dev_info was used for the mapping of btree
node caches.  This uses device dependent backing_dev_info to allow
detailed control of the device for the btree node pages.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This helps userland programs like the rmcp command to distinguish
error codes returned against a checkpoint removal request.

Previously -EPERM was returned, and not discriminable from real
permission errors.  This also allows removal of the latest checkpoint
because the deletion leads to create a new checkpoint, and thus it's
harmless for the filesystem.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This adds a missing sync_page method which unplugs bio requests when
waiting for page locks. This will improve read performance of nilfs.

Here is a measurement result using dd command.

Without this patch:

 # mount -t nilfs2 /dev/sde1 /test
 # dd if=/test/aaa of=/dev/null bs=512k
 1024+0 records in
 1024+0 records out
 536870912 bytes (537 MB) copied, 6.00688 seconds, 89.4 MB/s

With this patch:

 # mount -t nilfs2 /dev/sde1 /test
 # dd if=/test/aaa of=/dev/null bs=512k
 1024+0 records in
 1024+0 records out
 536870912 bytes (537 MB) copied, 3.54998 seconds, 151 MB/s
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This sets BIO_RW_UNPLUG flag on the last bio of each segment during
write.  The last bio should be unplugged immediately because the
caller waits for the completion after the submission.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Nilfs has some ioctl commands to read out metadata from meta data
files:

 - NILFS_IOCTL_GET_CPINFO for checkpoint file,
 - NILFS_IOCTL_GET_SUINFO for segment usage file, and
 - NILFS_IOCTL_GET_VINFO for Disk Address Transalation (DAT) file,
   respectively.

Every routine on these metadata files is implemented so that it allows
future expansion of on-disk format.  But, the above ioctl commands do
not support expansion even though nilfs_argv structure can handle
arbitrary size for data exchanged via ioctl.

This allows future expansion of the following structures which give
basic format of the "get information" ioctls:

 - struct nilfs_cpinfo
 - struct nilfs_suinfo
 - struct nilfs_vinfo

So, this introduces forward compatility of such ioctl commands.

In this patch, a sanity check in nilfs_ioctl_get_info() function is
changed to accept larger data structure [1], and metadata read
routines are rewritten so that they become compatible for larger
structures; the routines will just ignore the remaining fields which
the current version of nilfs doesn't know.

[1] The ioctl function already has another upper limit (PAGE_SIZE
    against a structure, which appears in nilfs_ioctl_wrap_copy
    function), and this will not cause security problem.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Hi,

I introduced "is_partially_uptodate" aops for NILFS2.

A page can have multiple buffers and even if a page is not uptodate, some buffers
can be uptodate on pagesize != blocksize environment.
This aops checks that all buffers which correspond to a part of a file
that we want to read are uptodate. If so, we do not have to issue actual
read IO to HDD even if a page is not uptodate because the portion we
want to read are uptodate.
"block_is_partially_uptodate" function is already used by ext2/3/4.
With the following patch random read/write mixed workloads or random read after
random write workloads can be optimized and we can get performance improvement.

I did a performance test using the sysbench.

1 --file-block-size=8K --file-total-size=2G --file-test-mode=rndrw --file-fsync-freq=0 --fil
e-rw-ratio=1 run

-2.6.30-rc5

Test execution summary:
    total time:                          151.2907s
    total number of events:              200000
    total time taken by event execution: 2409.8387
    per-request statistics:
         min:                            0.0000s
         avg:                            0.0120s
         max:                            0.9306s
         approx.  95 percentile:         0.0439s

Threads fairness:
    events (avg/stddev):           12500.0000/238.52
    execution time (avg/stddev):   150.6149/0.01

-2.6.30-rc5-patched

Test execution summary:
    total time:                          140.8828s
    total number of events:              200000
    total time taken by event execution: 2240.8577
    per-request statistics:
         min:                            0.0000s
         avg:                            0.0112s
         max:                            0.8750s
         approx.  95 percentile:         0.0418s

Threads fairness:
    events (avg/stddev):           12500.0000/218.43
    execution time (avg/stddev):   140.0536/0.01

arch: ia64
pagesize: 16k

Thanks.
Signed-off-by: NHisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

will remove indirect function calls using nilfs_btree_operations
table.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

will remove indirect function calls using nilfs_direct_operations
table.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Previously, the bmap codes of nilfs used three types of function
tables.  The abuse of indirect function calls decreased source
readability and suffered many indirect jumps which would confuse
branch prediction of processors.

This eliminates one type of the function tables,
nilfs_bmap_ptr_operations, which was used to dispatch low level
pointer operations of the nilfs bmap.

This adds a new integer variable "b_ptr_type" to nilfs_bmap struct,
and uses the value to select the pointer operations.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This will cut off 16 bytes from the nilfs_bmap struct which is
embedded in the on-memory inode of nilfs.

The b_high field was never used, and the b_low field stores a constant
value which can be determined by whether the inode uses btree for
block mapping or not.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

This indirect function is set to NULL only for gc cache inodes, but
the gc cache inodes never call this function.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Two get block function for btree nodes, nilfs_bmap_get_block() and
nilfs_bmap_get_new_block(), are called only from the btree codes.
This relocation will increase opportunities of compiler optimization.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>