Btrfs: check for actual acls rather than just xattrs when caching no acl

We have an optimization that will go ahead and cache no acls on an inode if
there are no xattrs on the inode.  This saves us a lookup later to check the
acls for writes or any other access.  The problem is I use selinux so I always
have an xattr on inodes, so make this test a little smarter and check for the
actual acl hash on the key and if it isn't there then we still get to cache no
acl which makes everybody who uses selinux a little happier.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: use a percpu to keep track of possibly pinned bytes

There are all of these checks in the ENOSPC code to see if committing the
transaction would free up enough space to make the allocation.  This is because
early on we just committed the transaction and hoped and prayed, which resulted
in cases where it took _forever_ to get an ENOSPC when we really were out of
space.  So we check space_info->bytes_pinned, except this isn't completely true
because it doesn't account for space we may free but are stuck in delayed refs.
So tests like xfstests 226 would fail because we wouldn't commit the transaction
to free up the data space.  So instead add a percpu counter that will be a
little fuzzier, it will add bytes as soon as we try to free up the space, and
remove any space it doesn't actually free up when we get around to doing the
actual free.  We then 0 out this counter every transaction period so we have a
better idea of how much space we will actually free up by committing this
transaction.  With this patch we now pass xfstests 226.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: stop using try_to_writeback_inodes_sb_nr to flush delalloc

try_to_writeback_inodes_sb_nr returns 1 if writeback is already underway, which
is completely fraking useless for us as we need to make sure pages are actually
written before we go and check if there are ordered extents.  So replace this
with an open coding of try_to_writeback_inodes_sb_nr minus the writeback
underway check so that we are sure to actually have flushed some dirty pages out
and will have ordered extents to use.  With this patch xfstests generic/273 now
passes.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: check if we can nocow if we don't have data space

We always just try and reserve data space when we write, but if we are out of
space but have prealloc'ed extents we should still successfully write.  This
patch will try and see if we can write to prealloc'ed space and if we can go
ahead and allow the write to continue.  With this patch we now pass xfstests
generic/274.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: remove btrfs_sector_sum structure

Using the structure btrfs_sector_sum to keep the checksum value is
unnecessary, because the extents that btrfs_sector_sum points to are
continuous, we can find out the expected checksums by btrfs_ordered_sum's
bytenr and the offset, so we can remove btrfs_sector_sum's bytenr. After
removing bytenr, there is only one member in the structure, so it makes
no sense to keep the structure, just remove it, and use a u32 array to
store the checksum value.

By this change, we don't use the while loop to get the checksums one by
one. Now, we can get several checksum value at one time, it improved the
performance by ~74% on my SSD (31MB/s -> 54MB/s).

test command:
 # dd if=/dev/zero of=/mnt/btrfs/file0 bs=1M count=1024 oflag=sync

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: cleanup redundant code in btrfs_submit_direct()

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: fix wrong mirror number tuning

Now reading the data from the target device of the replace operation is allowed,
so the mirror number that is greater than the stripes number of a chunk is valid,
we will tune it when we find there is no target device later. Fix it.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: cleanup orphaned root orphan item

I hit a weird problem were my root item had been deleted but the orphan item had
not.  This isn't necessarily a problem, but it keeps the file system from being
mounted.  To fix this we just need to axe the orphan item if we can't find the
fs root when we're putting them altogether.  With this patch I was able to
successfully mount my file system.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: make the chunk allocator completely tree lockless

When adjusting the enospc rules for relocation I ran into a deadlock because we
were relocating the only system chunk and that forced us to try and allocate a
new system chunk while holding locks in the chunk tree, which caused us to
deadlock.  To fix this I've moved all of the dev extent addition and chunk
addition out to the delayed chunk completion stuff.  We still keep the in-memory
stuff which makes sure everything is consistent.

One change I had to make was to search the commit root of the device tree to
find a free dev extent, and hold onto any chunk em's that we allocated in that
transaction so we do not allocate the same dev extent twice.  This has the side
effect of fixing a bug with balance that has been there ever since balance
existed.  Basically you can free a block group and it's dev extent and then
immediately allocate that dev extent for a new block group and write stuff to
that dev extent, all within the same transaction.  So if you happen to crash
during a balance you could come back to a completely broken file system.  This
patch should keep these sort of things from happening in the future since we
won't be able to allocate free'd dev extents until after the transaction
commits.  This has passed all of the xfstests and my super annoying stress test
followed by a balance.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: fix oops when recovering the file data by scrub function

We get oops while running btrfs replace start test,
------------[ cut here ]------------
kernel BUG at mm/filemap.c:608!
[SNIP]
Call Trace:
  [<ffffffffa04b36c7>] copy_nocow_pages_for_inode+0x217/0x3f0 [btrfs]
  [<ffffffffa04b34b0>] ? scrub_print_warning_inode+0x230/0x230 [btrfs]
  [<ffffffffa04b34b0>] ? scrub_print_warning_inode+0x230/0x230 [btrfs]
  [<ffffffffa04bb8ce>] iterate_extent_inodes+0x1ae/0x300 [btrfs]
  [<ffffffffa04bbab2>] iterate_inodes_from_logical+0x92/0xb0 [btrfs]
  [<ffffffffa04b34b0>] ? scrub_print_warning_inode+0x230/0x230 [btrfs]
  [<ffffffffa04b3b07>] copy_nocow_pages_worker+0x97/0x150 [btrfs]
  [<ffffffffa048eed4>] worker_loop+0x134/0x540 [btrfs]
  [<ffffffff816274ea>] ? __schedule+0x3ca/0x7f0
  [<ffffffffa048eda0>] ? btrfs_queue_worker+0x300/0x300 [btrfs]
  [<ffffffff8106f2f0>] kthread+0xc0/0xd0
  [<ffffffff8106f230>] ? flush_kthread_worker+0x80/0x80
  [<ffffffff8163181c>] ret_from_fork+0x7c/0xb0
  [<ffffffff8106f230>] ? flush_kthread_worker+0x80/0x80
[SNIP]
 RIP  [<ffffffff8111f4c5>] unlock_page+0x35/0x40
  RSP <ffff88010316bb98>
 ---[ end trace 421e79ad0dd72c7d ]---

it is because we forgot to lock the page again after we read data to
the page. Fix it.

Signed-off-by: Lin Feng <linfeng@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: cleanup the code of copy_nocow_pages_for_inode()

- It make no sense that we continue to do something after the error
  happened, just go back with this patch.
- remove some check of copy_nocow_pages_for_inode(), such as page check
  after write, inode check in the end of the function, because we are
  sure they exist.
- remove the unnecessary goto in the return value check of the write

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: fix several potential problems in copy_nocow_pages_for_inode

- It makes no sense that we deal with a inode in the dead tree.
- fix the race between dio and page copy by waiting the dio completion
- avoid the page copy vs truncate/punch hole
- check if the page is in the page cache or not

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: fix crash regarding to ulist_add_merge

Several users reported this crash of NULL pointer or general protection,
the story is that we add a rbtree for speedup ulist iteration, and we
use krealloc() to address ulist growth, and krealloc() use memcpy to copy
old data to new memory area, so it's OK for an array as it doesn't use
pointers while it's not OK for a rbtree as it uses pointers.

So krealloc() will mess up our rbtree and it ends up with crash.

Reviewed-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: make backref walking code handle skinny metadata

I missed fixing the backref stuff when I introduced the skinny metadata.  If you
try and do things like snapshot aware defrag with skinny metadata you are going
to see tons of warnings related to the backref count being less than 0.  This is
because the delayed refs will be found for stuff just fine, but it won't find
the skinny metadata extent refs.  With this patch I'm not seeing warnings
anymore.  Thanks,

Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: hold the tree mod lock in __tree_mod_log_rewind

We need to hold the tree mod log lock in __tree_mod_log_rewind since we walk
forward in the tree mod entries, otherwise we'll end up with random entries and
trip the BUG_ON() at the front of __tree_mod_log_rewind.  This fixes the panics
people were seeing when running

find /whatever -type f -exec btrfs fi defrag {} \;

Thansk,

Cc: stable@vger.kernel.org
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: only do the tree_mod_log_free_eb if this is our last ref

There is another bug in the tree mod log stuff in that we're calling
tree_mod_log_free_eb every single time a block is cow'ed.  The problem with this
is that if this block is shared by multiple snapshots we will call this multiple
times per block, so if we go to rewind the mod log for this block we'll BUG_ON()
in __tree_mod_log_rewind because we try to rewind a free twice.  We only want to
call tree_mod_log_free_eb if we are actually freeing the block.  With this patch
I no longer hit the panic in __tree_mod_log_rewind.  Thanks,

Cc: stable@vger.kernel.org
Reviewed-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Btrfs: wait ordered range before doing direct io

My recent truncate patch uncovered this bug, but I can reproduce it without the
truncate patch.  If you mount with -o compress-force, do a direct write to some
area, do a buffered write to some other area, and then do a direct read you will
get the wrong data for where you did the buffered write.  This is because the
generic direct io helpers only call filemap_write_and_wait once, and for
compression we need it twice.  So to be safe add the btrfs_wait_ordered_range to
the start of the direct io function to make sure any compressed writes have
truly been written.  This patch makes xfstests 130 pass when you mount with -o
compress-force=lzo.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
btrfs: set readdir f_pos only after filldir

The only time we need to advance f_pos is after we've successfully given
a result to userspace via filldir.  This simplification gets rid of the
is_curr variable used to update f_pos for the delayed item readdir
entries.

Signed-off-by: Zach Brown <zab@redhat.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
btrfs: fix readdir hang with offsets past INT_MAX

To work around bugs in userspace btrfs_real_readdir() sets f_pos to an
offset that will prevent any future entries from being returned once the
last entry is hit.  Over time this supposedly impossible offset was
decreased from the initial U64_MAX to INT_MAX to appease 32bit
userspace.

  https://oss.oracle.com/pipermail/btrfs-devel/2008-January/000437.html
  commit c2a8b6e11009398ca9363d8ba8d4e7e40fb897fd
  commit 89f135d8b53bcccafd91a075366d2704ba257cf3
  commit 406266ab9ac8ed8b085c58aacd9e3161480dc5d5

The remaining problem is that resetting f_pos to some impossible offset
causes userspace to spin when it's, well, possible for an entry to have
that offset.  It takes a single thread on a modern cpu about nine hours
of constant file creation and removal to hit an offset past INT_MAX on a
single spindle.

Instead of trying to find an impossible f_pos that doesn't break various
layers of the stack, let's use f_version to indicate that readdir should
stop returning entries until seek changes f_pos and clears f_version.

Signed-off-by: Zach Brown <zab@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
btrfs: trivial delayed item readdir list cleanups

Just call btrfs_put_delayed_items() for each list rather than having two
list arguments and duplicated code.

list_for_each_entry_safe() can handle an empty list.

We don't have to conditionally use and tear down the lists if we always
initialize them to be empty.  They're only populated when needed and the
rest of the uses just find empty lists.

Signed-off-by: Zach Brown <zab@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>