We loop through all of the dirty block groups during commit and write
the free space cache.  In order to make sure the cache is currect, we do
this while no other writers are allowed in the commit.

If a large number of block groups are dirty, this can introduce long
stalls during the final stages of the commit, which can block new procs
trying to change the filesystem.

This commit changes the block group cache writeout to take appropriate
locks and allow it to run earlier in the commit.  We'll still have to
redo some of the block groups, but it means we can get most of the work
out of the way without blocking the entire FS.
Signed-off-by: NChris Mason <clm@fb.com>

Signed-off-by: NDavid Sterba <dsterba@suse.cz>

All callers pass nodesize.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

Marc Merlin sent me a broken fs image months ago where it would blow up in the
upper->checked BUG_ON() in build_backref_tree.  This is because we had a
scenario like this

block a -- level 4 (not shared)
   |
block b -- level 3 (reloc block, shared)
   |
block c -- level 2 (not shared)
   |
block d -- level 1 (shared)
   |
block e -- level 0 (shared)

We go to build a backref tree for block e, we notice block d is shared and add
it to the list of blocks to lookup it's backrefs for.  Now when we loop around
we will check edges for the block, so we will see we looked up block c last
time.  So we lookup block d and then see that the block that points to it is
block c and we can just skip that edge since we've already been up this path.
The problem is because we clear need_check when we see block d (as it is shared)
we never add block b as needing to be checked.  And because block c is in our
path already we bail out before we walk up to block b and add it to the backref
check list.

To fix this we need to reset need_check if we trip over a block that doesn't
need to be checked.  This will make sure that any subsequent blocks in the path
as we're walking up afterwards are added to the list to be processed.  With this
patch I can now mount Marc's fs image and it'll complete the balance without
panicing.  Thanks,
Reported-by: NMarc MERLIN <marc@merlins.org>
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

When balance panics it tends to panic in the

BUG_ON(!upper->checked);

test, because it means it couldn't build the backref tree properly.  This is
annoying to users and frankly a recoverable error, nothing in this function is
actually fatal since it is just an in-memory building of the backrefs for a
given bytenr.  So go through and change all the BUG_ON()'s to ASSERT()'s, and
fix the BUG_ON(!upper->checked) thing to just return an error.

This patch also fixes the error handling so it tears down the work we've done
properly.  This code was horribly broken since we always just panic'ed instead
of actually erroring out, so it needed to be completely re-worked.  With this
patch my broken image no longer panics when I mount it.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

Signed-off-by: NDavid Sterba <dsterba@suse.cz>

We know the tree block size, no need to pass it around.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

It's trivial with a single user. And remove one pointless BUG_ON.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

The parent_transid parameter has been unused since its introduction in
ca7a79ad ("Pass down the expected generation number when reading
tree blocks").  In reada_tree_block, it was even wrongly set to leafsize.
Transid check is done in the proper read and readahead ignores errors.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

The nodesize and leafsize were never of different values. Unify the
usage and make nodesize the one. Cleanup the redundant checks and
helpers.

Shaves a few bytes from .text:

  text    data     bss     dec     hex filename
852418   24560   23112  900090   dbbfa btrfs.ko.before
851074   24584   23112  898770   db6d2 btrfs.ko.after
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

I've noticed an extra line after "use no compression", but search
revealed much more in messages of more critical levels and rare errors.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <clm@fb.com>

Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

This was done to allow NO_COW to continue to be NO_COW after relocation but it
is not right.  When relocating we will convert blocks to FULL_BACKREF that we
relocate.  We can leave some of these full backref blocks behind if they are not
cow'ed out during the relocation, like if we fail the relocation with ENOSPC and
then just drop the reloc tree.  Then when we go to cow the block again we won't
lookup the extent flags because we won't think there has been a snapshot
recently which means we will do our normal ref drop thing instead of adding back
a tree ref and dropping the shared ref.  This will cause btrfs_free_extent to
blow up because it can't find the ref we are trying to free.  This was found
with my ref verifying tool.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

We needn't flush all delalloc inodes when we doesn't get s_umount lock,
or we would make the tasks wait for a long time.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fb.com>

During balance test, we hit an oops:
[ 2013.841551] kernel BUG at fs/btrfs/relocation.c:1174!

The problem is that if we fail to relocate tree blocks, we should
update backref cache, otherwise, some pending nodes are not updated
while snapshot check @cache->last_trans is within one transaction
and won't update it and then oops happen.
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

Previously, we will free reloc root memory and then force filesystem
to be readonly. The problem is that there may be another thread commiting
transaction which will try to access freed reloc root during merging reloc
roots process.

To keep consistency snapshots shared space, we should allow snapshot
finished if possible, so here we don't free reloc root memory.
signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

@nr is no longer used, remove it from select_reloc_root()
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

Convert all applicable cases of printk and pr_* to the btrfs_* macros.

Fix all uses of the BTRFS prefix.
Signed-off-by: NFrank Holton <fholton@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

We have commited transaction before, remove redundant filemap writting and
waiting here, it can speed up balance relocation process.
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

We hit a forever loop when doing balance relocation,the reason
is that we firstly reserve 4M(node size is 16k).and within transaction
we will try to add extra reservation for snapshot roots,this will
return -EAGAIN if there has been a thread flushing space to reserve
space.We will do this again and again with filesystem becoming nearly
full.

If the above '-EAGAIN' case happens, we try to refill reservation more
outsize of transaction, and this will return eariler in enospc case,however,
this dosen't really hurt because it makes no sense doing balance relocation
with the filesystem nearly full.

Miao Xie helped a lot to track this issue, thanks.
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

I hit an oops when merging reloc roots fails, the reason is that
new reloc roots may be added and we should make sure we cleanup
all reloc roots.
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

Quota tree and UUID Tree is only cowed, they can not be snapshoted.
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

I hit an oops when inserting reloc root into @reloc_root_tree(it can be
easily triggered when forcing cow for relocation root)

[  866.494539]  [<ffffffffa0499579>] btrfs_init_reloc_root+0x79/0xb0 [btrfs]
[  866.495321]  [<ffffffffa044c240>] record_root_in_trans+0xb0/0x110 [btrfs]
[  866.496109]  [<ffffffffa044d758>] btrfs_record_root_in_trans+0x48/0x80 [btrfs]
[  866.496908]  [<ffffffffa0494da8>] select_reloc_root+0xa8/0x210 [btrfs]
[  866.497703]  [<ffffffffa0495c8a>] do_relocation+0x16a/0x540 [btrfs]

This is because reloc root inserted into @reloc_root_tree is not within one
transaction,reloc root may be cowed and root block bytenr will be reused then
oops happens.We should update reloc root in @reloc_root_tree when cow reloc
root node, fix it.
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <clm@fb.com>

rename the function -- btrfs_start_all_delalloc_inodes(), and make its
name be compatible to btrfs_wait_ordered_roots(), since they are always
used at the same place.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

It is very likely that there are lots of ordered extents in the filesytem,
if we wait for the completion of all of them when we want to reclaim some
space for the metadata space reservation, we would be blocked for a long
time. The performance would drop down suddenly for a long time.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Use WARN_ON()'s return value in place of WARN_ON(1) for cleaner source
code that outputs a more descriptive warnings. Also fix the styling
warning of redundant braces that came up as a result of this fix.
Signed-off-by: NDulshani Gunawardhana <dulshani.gunawardhana89@gmail.com>
Reviewed-by: NZach Brown <zab@redhat.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

We define a 'int' to get extent's generation by mistake,fix it.
Signed-off-by: NWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

I noticed with my horrible snapshot excercisor that we were taking forever to
relocate the larger the file system got.  This appeared to be because we were
committing the transaction _constantly_.  There were a few places where we do
braindead things with metadata reservation, like start a transaction and then
try to refill the block rsv, which not only keeps us from committing a
transaction during the enospc stuff, but keeps us from doing some of the harder
flushing work which will make us more likely to need to commit the transaction.
We also were checking the block rsv and committing the transaction if the block
rsv was below a certain threshold, but we were doing this in a place where we
don't actually keep anything in the block rsv so this was always ending up false
so we always committed the transaction in this case.  I tested this to make sure
it didn't break anything, but it takes about 10 hours to get the box to this
state so I don't know how much of an impact it will really make.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

I noticed that if the free space cache has an error writing out it's data it
won't actually error out, it will just carry on.  This is because it doesn't
check the return value of btrfs_wait_ordered_range, which didn't actually return
anything.  So fix this in order to keep us from making free space cache look
valid when it really isnt.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

When we did space balance and snapshot creation at the same time, we might
meet the following oops:
 kernel BUG at fs/btrfs/inode.c:3038!
 [SNIP]
 Call Trace:
 [<ffffffffa0411ec7>] btrfs_orphan_cleanup+0x293/0x407 [btrfs]
 [<ffffffffa042dc45>] btrfs_mksubvol.isra.28+0x259/0x373 [btrfs]
 [<ffffffffa042de85>] btrfs_ioctl_snap_create_transid+0x126/0x156 [btrfs]
 [<ffffffffa042dff1>] btrfs_ioctl_snap_create_v2+0xd0/0x121 [btrfs]
 [<ffffffffa0430b2c>] btrfs_ioctl+0x414/0x1854 [btrfs]
 [<ffffffff813b60b7>] ? __do_page_fault+0x305/0x379
 [<ffffffff811215a9>] vfs_ioctl+0x1d/0x39
 [<ffffffff81121d7c>] do_vfs_ioctl+0x32d/0x3e2
 [<ffffffff81057fe7>] ? finish_task_switch+0x80/0xb8
 [<ffffffff81121e88>] SyS_ioctl+0x57/0x83
 [<ffffffff813b39ff>] ? do_device_not_available+0x12/0x14
 [<ffffffff813b99c2>] system_call_fastpath+0x16/0x1b
 [SNIP]
 RIP  [<ffffffffa040da40>] btrfs_orphan_add+0xc3/0x126 [btrfs]

The reason of the problem is that the relocation root creation stole
the reserved space, which was reserved for orphan item deletion.

There are several ways to fix this problem, one is to increasing
the reserved space size of the space balace, and then we can use
that space to create the relocation tree for each fs/file trees.
But it is hard to calculate the suitable size because we doesn't
know how many fs/file trees we need relocate.

We fixed this problem by reserving the space for relocation root creation
actively since the space it need is very small (one tree block, used for
root node copy), then we use that reserved space to create the
relocation tree. If we don't reserve space for relocation tree creation,
we will use the reserved space of the balance.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

A user reported a problem where they were getting csum errors when running a
balance and running systemd's journal.  This is because systemd is awesome and
fallocate()'s its log space and writes into it.  Unfortunately we assume that
when we read in all the csums for an extent that they are sequential starting at
the bytenr we care about.  This obviously isn't the case for prealloc extents,
where we could have written to the middle of the prealloc extent only, which
means the csum would be for the bytenr in the middle of our range and not the
front of our range.  Fix this by offsetting the new bytenr we are logging to
based on the original bytenr the csum was for.  With this patch I no longer see
the csum errors I was seeing.  Thanks,

Cc: stable@vger.kernel.org
Reported-by: NChris Murphy <lists@colorremedies.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Not used for anything, and removing it avoids caller's need to
allocate a path structure.
Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

When doing space balance and subvolume destroy at the same time, we met
the following oops:

kernel BUG at fs/btrfs/relocation.c:2247!
RIP: 0010: [<ffffffffa04cec16>] prepare_to_merge+0x154/0x1f0 [btrfs]
Call Trace:
 [<ffffffffa04b5ab7>] relocate_block_group+0x466/0x4e6 [btrfs]
 [<ffffffffa04b5c7a>] btrfs_relocate_block_group+0x143/0x275 [btrfs]
 [<ffffffffa0495c56>] btrfs_relocate_chunk.isra.27+0x5c/0x5a2 [btrfs]
 [<ffffffffa0459871>] ? btrfs_item_key_to_cpu+0x15/0x31 [btrfs]
 [<ffffffffa048b46a>] ? btrfs_get_token_64+0x7e/0xcd [btrfs]
 [<ffffffffa04a3467>] ? btrfs_tree_read_unlock_blocking+0xb2/0xb7 [btrfs]
 [<ffffffffa049907d>] btrfs_balance+0x9c7/0xb6f [btrfs]
 [<ffffffffa049ef84>] btrfs_ioctl_balance+0x234/0x2ac [btrfs]
 [<ffffffffa04a1e8e>] btrfs_ioctl+0xd87/0x1ef9 [btrfs]
 [<ffffffff81122f53>] ? path_openat+0x234/0x4db
 [<ffffffff813c3b78>] ? __do_page_fault+0x31d/0x391
 [<ffffffff810f8ab6>] ? vma_link+0x74/0x94
 [<ffffffff811250f5>] vfs_ioctl+0x1d/0x39
 [<ffffffff811258c8>] do_vfs_ioctl+0x32d/0x3e2
 [<ffffffff811259d4>] SyS_ioctl+0x57/0x83
 [<ffffffff813c3bfa>] ? do_page_fault+0xe/0x10
 [<ffffffff813c73c2>] system_call_fastpath+0x16/0x1b

It is because we returned the error number if the reference of the root was 0
when doing space relocation. It was not right here, because though the root
was dead(refs == 0), but the space it held still need be relocated, or we
could not remove the block group. So in this case, we should return the root
no matter it is dead or not.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

This is a left over of how we used to wait for ordered extents, which was to
grab the inode and then run filemap flush on it.  However if we have an ordered
extent then we already are holding a ref on the inode, and we just use
btrfs_start_ordered_extent anyway, so there is no reason to have an extra ref on
the inode to start work on the ordered extent.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

If we failed to actually allocate the correct size of the extent to relocate we
will end up in an infinite loop because we won't return an error, we'll just
move on to the next extent.  So fix this up by returning an error, and then fix
all the callers to return an error up the stack rather than BUG_ON()'ing.
Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

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 three more places.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

u64 is "unsigned long long" on all architectures now, so there's no need to
cast it when formatting it using the "ll" length modifier.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

Previously we only added blocks to the list to have their backrefs checked if
the level of the block is right above the one we are searching for.  This is
because we want to make sure we don't add the entire path up to the root to the
lists to make sure we process things one at a time.  This assumes that if any
blocks in the path to the root are going to be not checked (shared in other
words) then they will be in the level right above the current block on up.  This
isn't quite right though since we can have blocks higher up the list that are
shared because they are attached to a reloc root.  But we won't add this block
to be checked and then later on we will BUG_ON(!upper->checked).  So instead
keep track of wether or not we've queued a block to be checked in this current
search, and if we haven't go ahead and queue it to be checked.  This patch fixed
the panic I was seeing where we BUG_ON(!upper->checked).  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>

If our item isn't big enough to have an actual inline item when we have skinny
metadata enabled just return 1 in find_inline_backref so we can move on to the
next item.  This probably wasn't causing a problem since we check the values of
ptr and end properly, but just in case this will keep us from doing extra work.
Thanks,
Signed-off-by: NJosef Bacik <jbacik@fusionio.com>
Signed-off-by: NChris Mason <chris.mason@fusionio.com>