UBIFS: correct mount message

When mounting an UBIFS R/W volume, we have the message:
UBIFS: mounted UBI device 0, volume 1, name "rootfs"(null)
With this patch, we'll have:
UBIFS: mounted UBI device 0, volume 1, name "rootfs"
Which is, I think, what was intended.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Cc: stable@vger.kernel.org [v3.7+]
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Add wait_on_atomic_t() and wake_up_atomic_t()

Add wait_on_atomic_t() and wake_up_atomic_t() to indicate became-zero events on
atomic_t types.  This uses the bit-wake waitqueue table.  The key is set to a
value outside of the number of bits in a long so that wait_on_bit() won't be
woken up accidentally.

What I'm using this for is: in a following patch I add a counter to struct
fscache_cookie to count the number of outstanding operations that need access
to netfs data.  The way this works is:

 (1) When a cookie is allocated, the counter is initialised to 1.

 (2) When an operation wants to access netfs data, it calls atomic_inc_unless()
     to increment the counter before it does so.  If it was 0, then the counter
     isn't incremented, the operation isn't permitted to access the netfs data
     (which might by this point no longer exist) and the operation aborts in
     some appropriate manner.

 (3) When an operation finishes with the netfs data, it decrements the counter
     and if it reaches 0, calls wake_up_atomic_t() on it - the assumption being
     that it was the last blocker.

 (4) When a cookie is released, the counter is decremented and the releaser
     uses wait_on_atomic_t() to wait for the counter to become 0 - which should
     indicate no one is using the netfs data any longer.  The netfs data can
     then be destroyed.

There are some alternatives that I have thought of and that have been suggested
by Tejun Heo:

 (A) Using wait_on_bit() to wait on a bit in the counter.  This doesn't work
     because if that bit happens to be 0 then the wait won't happen - even if
     the counter is non-zero.

 (B) Using wait_on_bit() to wait on a flag elsewhere which is cleared when the
     counter reaches 0.  Such a flag would be redundant and would add
     complexity.

 (C) Adding a waitqueue to fscache_cookie - this would expand that struct by
     several words for an event that happens just once in each cookie's
     lifetime.  Further, cookies are generally per-file so there are likely to
     be a lot of them.

 (D) Similar to (C), but add a pointer to a waitqueue in the cookie instead of
     a waitqueue.  This would add single word per cookie and so would be less
     of an expansion - but still an expansion.

 (E) Adding a static waitqueue to the fscache module.  Generally this would be
     fine, but under certain circumstances many cookies will all get added at
     the same time (eg. NFS umount, cache withdrawal) thereby presenting
     scaling issues.  Note that the wait may be significant as disk I/O may be
     in progress.

So, I think reusing the wait_on_bit() waitqueue set is reasonable.  I don't
make much use of the waitqueue I need on a per-cookie basis, but sometimes I
have a huge flood of the cookies to deal with.

I also don't want to add a whole new set of global waitqueue tables
specifically for the dec-to-0 event if I can reuse the bit tables.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-By: Milosz Tanski <milosz@adfin.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Btrfs: fix check on same raid type flag twice

Code checked for raid 5 flag in two else-if branches, so code would never be reached. Probably a copy-paste bug.

Signed-off-by: Henrik Nordvik <henrikno@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
btrfs: add debug check for extent_io range alignment

The 'end' value must exactly cover the end of the interval, which means
one byte less than the expected block alignment, or in case of a file
smaller than one block, one byte less than the inode size.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
btrfs: add prefix to sanity tests messages

And change the message level to KERN_INFO.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
btrfs: move ifdef around sanity checks out of init_btrfs_fs

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
btrfs: show compiled-in config features at module load time

We want to know if there are debugging features compiled in, this may
affect performance. The message is printed before the sanity checks.
Also kill version.h file that serves no purpose, we don't use any
version tag for kernel module.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: introduce qgroup_ulist to avoid frequently allocating/freeing ulist

When doing qgroup accounting, we call ulist_alloc()/ulist_free() every time
when we want to walk qgroup tree.

By introducing 'qgroup_ulist', we only need to call ulist_alloc()/ulist_free()
once. This reduce some sys time to allocate memory, see the measurements below

fsstress -p 4 -n 10000 -d $dir

With this patch:

real    0m50.153s
user    0m0.081s
sys     0m6.294s

real    0m51.113s
user    0m0.092s
sys     0m6.220s

real    0m52.610s
user    0m0.096s
sys     0m6.125s	avg 6.213
-----------------------------------------------------
Without the patch:

real    0m54.825s
user    0m0.061s
sys     0m10.665s

real    1m6.401s
user    0m0.089s
sys     0m11.218s

real    1m13.768s
user    0m0.087s
sys     0m10.665s       avg 10.849

we can see the sys time reduce ~43%.

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: add ioctl to wait for qgroup rescan completion

btrfs_qgroup_wait_for_completion waits until the currently running qgroup
operation completes. It returns immediately when no rescan process is in
progress. This is useful to automate things around the rescan process (e.g.
testing).

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: fix a comment

The size parameter to btrfs_extend_item() is the number of bytes
to add to the item, not the size of the item after the operation
(like it is for btrfs_truncate_item(), there the size parameter
is not the number of bytes to take away, but the total size of
the item after truncation).
Fix it in the comment.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: cleanup unused arguments in send.c

sctx is removed from the argument of the function that
doesn't use sctx.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Minor format cleanup.

Clean up the format of the definitions of BTRFS_BLOCK_GROUP_RAID5 and
BTRFS_BLOCK_GROUP_RAID6.

Signed-off-by: Andreas Philipp <philipp.andreas@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: remove useless copy in quota_ctl

We don't need to copy it back to user side as it remains unchanged.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: delete unused function

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: cleanup, btrfs_read_fs_root_no_name() doesn't return NULL

No need to check for NULL in send.c and disk-io.c.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: cleanup: don't check the same thing twice

btrfs_read_fs_root_no_name() already checks if btrfs_root_refs()
is zero and returns ENOENT in this case. There is no need to do
it again in six places.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: remove unnecessary ->s_umount in cleaner_kthread()

In order to avoid the R/O remount, we acquired ->s_umount lock during
we deleted the dead snapshots and subvolumes. But it is unnecessary,
because we have cleaner_mutex.

We use cleaner_mutex to protect the process of the dead snapshots/subvolumes
deletion. And when we remount the fs to be R/O, we also acquire this mutex to
do cleanup after we change the status of the fs. That is this lock can serialize
the above operations, the cleaner can be aware of the status of the fs, and if
the cleaner is deleting the dead snapshots/subvolumes, the remount task will
wait for it. So it is safe to remove ->s_umount in cleaner_kthread().

Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: make the cleaner complete early when the fs is going to be umounted

Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: move the R/O check out of btrfs_clean_one_deleted_snapshot()

If the fs is remounted to be R/O, it is unnecessary to call
btrfs_clean_one_deleted_snapshot(), so move the R/O check out of
this function. And besides that, it can make the check logic in the
caller more clear.

Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: make the snap/subv deletion end more early when the fs is R/O

The snapshot/subvolume deletion might spend lots of time, it would make
the remount task wait for a long time. This patch improve this problem,
we will break the deletion if the fs is remounted to be R/O. It will make
the users happy.

Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>