We've been seeing warnings coming out of the orphan commit stuff forever from
ceph.  Turns out it's because we're racing with checking if the orphan block
reserve is set, because we clear it outside of the spin_lock.  So leave the
normal fastpath checks where they are, but take the spin_lock and _recheck_ to
make sure we haven't had an orphan block rsv added in the meantime.  Then clear
the root's orphan block rsv and release the lock.  With this patch a user said
the warnings went away and they usually showed up pretty soon after he started
ceph.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

If updating the inode gave us an ENOSPC we were just returning in page_mkwrite,
which is a problem since we make our reservation right before trying to update
the inode, so fix the out label so that we actually free our reservation.
Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Reproduce steps:
 # mkfs.btrfs /dev/sdb5
 # mount /dev/sdb5 -o compress=lzo /mnt
 # dd if=/dev/zero of=/mnt/tmpfile bs=128K count=1
 # sync
 # truncate -s 64K /mnt/tmpfile
 root 5 inode 257 errors 400

This is because of the wrong if condition, which is used to check if we should
subtract the bytes of the dropped range from i_blocks/i_bytes of i-node or not.
When we truncate a compressed extent, btrfs substracts the bytes of the whole
extent, it's wrong. We should substract the real size that we truncate, no
matter it is a compressed extent or not. Fix it.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

A user reported a problem where things like open with O_CREAT would take up to
30 seconds when he had nfs activity on the same mount.  This is because all of
our quick metadata operations, like create, symlink etc all do
btrfs_end_transaction_throttle, which if the transaction is blocked will wait
for the commit to complete before it returns.  This adds a ridiculous amount of
latency and isn't really needed.  The normal btrfs_end_transaction will mark the
transaction as blocked and wake the transaction kthread up if it thinks the
transaction needs to end (this being in the running out of global reserve space
scenario), and this is all that is really needed since we've already done
everything we're going to do, we just need to return.  This should help people
with the latency they were seeing when using synchronous heavy workloads.
Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

There's code in btrfs_get_extent that should never be used. This patch turns
a WARN_ON(1) into a BUG(), hoping we can remove the transaction code from
btrfs_get_extent soon.
Signed-off-by: NJan Schmidt <list.btrfs@jan-o-sch.net>

This closes races where btrfs is calling d_instantiate too soon during
inode creation.  All of the callers of btrfs_add_nondir are updated to
instantiate after the inode is fully setup in memory.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Add a for_cow parameter to add_delayed_*_ref and pass the appropriate value
from every call site. The for_cow parameter will later on be used to
determine if a ref will change anything with respect to qgroups.

Delayed refs coming from relocation are always counted as for_cow, as they
don't change subvol quota.

Also pass in the fs_info for later use.

btrfs_find_all_roots() will use this as an optimization, as changes that are
for_cow will not change anything with respect to which root points to a
certain leaf. Thus, we don't need to add the current sequence number to
those delayed refs.
Signed-off-by: NArne Jansen <sensille@gmx.net>
Signed-off-by: NJan Schmidt <list.btrfs@jan-o-sch.net>

I've been hitting this BUG_ON() in btrfs_orphan_add when running xfstest 269 in
a loop.  This is because we will add an orphan item, do the truncate, the
truncate will fail for whatever reason (*cough*ENOSPC*cough*) and then we're
left with an orphan item still in the fs.  Then we come back later to do another
truncate and it blows up because we already have an orphan item.  This is ok so
just fix the BUG_ON() to only BUG() if ret is not EEXIST.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

We were occasionaly leaking space when running xfstest 269.  This is because if
we failed to start the transaction in the truncate loop we'd just goto out, but
we need to break so that the inode is removed from the orphan list and the space
is properly freed.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Running xfstests 269 with some tracing my scripts kept spitting out errors about
releasing bytes that we didn't actually have reserved.  This took me down a huge
rabbit hole and it turns out the way we deal with reserved_extents is wrong,
we need to only be setting it if the reservation succeeds, otherwise the free()
method will come in and unreserve space that isn't actually reserved yet, which
can lead to other warnings and such.  The math was all working out right in the
end, but it caused all sorts of other issues in addition to making my scripts
yell and scream and generally make it impossible for me to track down the
original issue I was looking for.  The other problem is with our error handling
in the reservation code.  There are two cases that we need to deal with

1) We raced with free.  In this case free won't free anything because csum_bytes
is modified before we dro the lock in our reservation path, so free rightly
doesn't release any space because the reservation code may be depending on that
reservation.  However if we fail, we need the reservation side to do the free at
that point since that space is no longer in use.  So as it stands the code was
doing this fine and it worked out, except in case #2

2) We don't race with free.  Nobody comes in and changes anything, and our
reservation fails.  In this case we didn't reserve anything anyway and we just
need to clean up csum_bytes but not free anything.  So we keep track of
csum_bytes before we drop the lock and if it hasn't changed we know we can just
decrement csum_bytes and carry on.

Because of the case where we can race with free()'s since we have to drop our
spin_lock to do the reservation, I'm going to serialize all reservations with
the i_mutex.  We already get this for free in the heavy use paths, truncate and
file write all hold the i_mutex, just needed to add it to page_mkwrite and
various ioctl/balance things.  With this patch my space leak scripts no longer
scream bloody murder.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Now that we're properly keeping track of delayed inode space we've been getting
a lot of warnings out of btrfs_dirty_inode() when running xfstest 83.  This is
because a bunch of people call mark_inode_dirty, which is void so we can't
return ENOSPC.  This needs to be fixed in a few areas

1) file_update_time - this updates the mtime and such when writing to a file,
which will call mark_inode_dirty.  So copy file_update_time into btrfs so we can
call btrfs_dirty_inode directly and return an error if we get one appropriately.

2) fix symlinks to use btrfs_setattr for ->setattr.  For some reason we weren't
setting ->setattr for symlinks, even though we should have been.  This catches
one of the cases where we were getting errors in mark_inode_dirty.

3) Fix btrfs_setattr and btrfs_setsize to call btrfs_dirty_inode directly
instead of mark_inode_dirty.  This lets us return errors properly for truncate
and chown/anything related to setattr.

4) Add a new btrfs_fs_dirty_inode which will just call btrfs_dirty_inode and
print an error if we have one.  The only remaining user we can't control for
this is touch_atime(), but we don't really want to keep people from walking
down the tree if we don't have space to save the atime update, so just complain
but don't worry about it.

With this patch xfstests 83 complains a handful of times instead of hundreds of
times.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

The Smack LSM hook for security_d_instantiate checks
the inode's i_op->getxattr value to determine if the
containing filesystem supports extended attributes.
The BTRFS filesystem sets the inode's i_op value only
after it has instantiated the inode. This results in
Smack incorrectly giving new BTRFS inodes attributes
from the filesystem defaults on the assumption that
values can't be stored on the filesystem. This patch
moves the assignment of inode operation vectors ahead
of the calls to d_instantiate, letting Smack know that
the filesystem supports extended attributes. There
should be no impact on the performance or behavior of
BTRFS.
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Since we have the free space caches, btrfs_orphan_cleanup also runs for
the tree_root. Unfortunately this also cleans up the orphans used to mark
subvol deletions in progress.

Currently if a subvol deletion gets interrupted twice by umount/mount, the
deletion will not be continued and the space permanently lost, though it
would be possible to write a tool to recover those lost subvol deletions.
This patch checks if the orphan belongs to a subvol (dead root) and skips
the deletion.
Signed-off-by: NArne Jansen <sensille@gmx.net>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Btrfsck report errors after the 83th case of xfstests was run, The error
number is 400, it means the used disk space of the file is wrong.

The reason of this bug is that:
The file truncation may fail when the space of the file system is not enough,
and leave some file extents, whose offset are beyond the end of the files.
When we want to expand those files, we will drop those file extents, and
put in dummy file extents, and then we should update the i-node. But btrfs
forgets to do it.

This patch adds the forgotten i-node update.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Btrfsck report error 100 after the 83th case of xfstests was run, it means
the i_size of the file is wrong.

The reason of this bug is that:
Btrfs increased i_size of the file at the beginning, but it failed to expand
the file, and failed to update the i_size to the old size because there is no
enough space in the file system, so we found a wrong i_size.

This patch fixes this bug by updating the i_size just when we pass the file
expanding and get enough space to update i-node.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

When I ran the xfstests, I found the test tasks was blocked on meta-data
reservation.

By debugging, I found the reason of this bug:
   start transaction
        |
	v
   reserve meta-data space
	|
	v
   flush delay allocation -> iput inode -> evict inode
	^					|
	|					v
   wait for delay allocation flush <- reserve meta-data space

And besides that, the flush on evicting inode will block the thread, which
is reclaiming the memory, and make oom happen easily.

Fix this bug by skipping the flush step when evicting inode.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>

Round inode bytes and delalloc bytes up to real blocksize before
converting to sector size. Otherwise eg. files smaller than 512
are reported with zero blocks due to incorrect rounding.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

When we did stress test for the space relocation, the deadlock happened.
By debugging, We found it was caused by the carelessness that we forgot
to unlock the read lock of the extent buffers in btrfs_orphan_cleanup()
before we end the transaction handle, so the transaction commit task waited
the task, which called btrfs_orphan_cleanup(), to unlock the extent buffer,
but that task waited the commit task to end the transaction commit, and
the deadlock happened. Fix it.
Signed-ff-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Josef sent along an incremental to the inode reservation
code to make sure we try and fall back to directly updating
the inode item if things go horribly wrong.

This reworks that patch slightly, adding a fallback function
that will always try to update the inode item directly without
going through the delayed_inode code.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

People have been reporting ENOSPC crashes in finish_ordered_io.  This is because
we try to steal from the delalloc block rsv to satisfy a reservation to update
the inode.  The problem with this is we don't explicitly save space for updating
the inode when doing delalloc.  This is kind of a problem and we've gotten away
with this because way back when we just stole from the delalloc reserve without
any questions, and this worked out fine because generally speaking the leaf had
been modified either by the mtime update when we did the original write or
because we just updated the leaf when we inserted the file extent item, only on
rare occasions had the leaf not actually been modified, and that was still ok
because we'd just use a block or two out of the over-reservation that is
delalloc.

Then came the delayed inode stuff.  This is amazing, except it wants a full
reservation for updating the inode since it may do it at some point down the
road after we've written the blocks and we have to recow everything again.  This
worked out because the delayed inode stuff just stole from the global reserve,
that is until recently when I changed that because it caused other problems.

So here we are, we're doing everything right and being screwed for it.  So take
an extra reservation for the inode at delalloc reservation time and carry it
through the life of the delalloc reservation.  If we need it we can steal it in
the delayed inode stuff.  If we have already stolen it try and do a normal
metadata reservation.  If that fails try to steal from the delalloc reservation.
If _that_ fails we'll get a WARN_ON() so I can start thinking of a better way to
solve this and in the meantime we'll steal from the global reserve.

With this patch I ran xfstests 13 in a loop for a couple of hours and didn't see
any problems.
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

If we fail to reserve space in the transaction during truncate, we can
error out with a NULL trans handle.  The cleanup code needs an extra
check to make sure we aren't trying to use the bad handle.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

fs_info has now ~9kb, more than fits into one page. This will cause
mount failure when memory is too fragmented. Top space consumers are
super block structures super_copy and super_for_commit, ~2.8kb each.
Allocate them dynamically. fs_info will be ~3.5kb. (measured on x86_64)

Add a wrapper for freeing fs_info and all of it's dynamically allocated
members.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

I fixed a problem where we weren't reserving space for an orphan item when we
had to fallback to using the global reserve for an unlink, but I introduced
another problem.  I was migrating the bytes from the transaction reserve to the
global reserve and then releasing from the global reserve in
btrfs_end_transaction().  The problem with this is that a migrate will jack up
the size for the destination, but leave the size alone for the source, with the
idea that you can do a release normally on the source and it all washes out, and
then you can do a release again on the destination and it works out right.  My
way was skipping the release on the trans_block_rsv which still had the jacked
up size from our original reservation.  So instead release manually from the
global reserve if this transaction was using it, and then set the
trans->block_rsv back to the trans_block_rsv so that btrfs_end_transaction
cleans everything up properly.  With this patch xfstest 83 doesn't emit warnings
about leaking space.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Replace remaining direct i_nlink updates with a new set_nlink()
updater function.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Tested-by: NToshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

To reproduce the bug:

  # mount -o nodatacow /dev/sda7 /mnt/
  # dd if=/dev/zero of=/mnt/tmp bs=4K count=1
  1+0 records in
  1+0 records out
  4096 bytes (4.1 kB) copied, 0.000136115 s, 30.1 MB/s
  # dd if=/dev/zero of=/mnt/tmp bs=4K count=1 conv=notrunc oflag=direct
  dd: writing `/mnt/tmp': Input/output error
  1+0 records in
  0+0 records out

btrfs_ordered_update_i_size() may return 1, but btrfs_endio_direct_write()
mistakenly takes it as an error.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

It's not a big deal if we fail to allocate the array, and instead of
panic we can just give up compressing.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

Currently btrfs_block_rsv_check does 2 things, it will either refill a block
reserve like in the truncate or refill case, or it will check to see if there is
enough space in the global reserve and possibly refill it.  However because of
overcommit we could be well overcommitting ourselves just to try and refill the
global reserve, when really we should just be committing the transaction.  So
breack this out into btrfs_block_rsv_refill and btrfs_block_rsv_check.  Refill
will try to reserve more metadata if it can and btrfs_block_rsv_check will not,
it will only tell you if the factor of the total space is still reserved.
Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

In __unlink_start_trans() if we don't have enough room for a reservation we will
check to see if the unlink will free up space.  If it does that's great, but we
will still could add an orphan item, so we need to reserve enough space to add
the orphan item.  Do this and migrate the space the global reserve so it all
works out right.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Our unlink reservations were a bit much, we were reserving 10 and I only count 8
possible items we're touching, so comment what we're reserving for and fix the
count value.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Yeah yeah I know this is how we used to do it and then I changed it, but damnit
I'm changing it back.  The fact is that writing out checksums will modify
metadata, which could cause us to dirty a block group we've already written out,
so we have to truncate it and all of it's checksums and re-write it which will
write new checksums which could dirty a blockg roup that has already been
written and you see where I'm going with this?  This can cause unmount or really
anything that depends on a transaction to commit to take it's sweet damned time
to happen.  So go back to the way it was, only this time we're specifically
setting NODATACOW because we can't go through the COW pathway anyway and we're
doing our own built-in cow'ing by truncating the free space cache.  The other
new thing is once we truncate the old cache and preallocate the new space, we
don't need to do that song and dance at all for the rest of the transaction, we
can just overwrite the existing space with the new cache if the block group
changes for whatever reason, and the NODATACOW will let us do this fine.  So
keep track of which transaction we last cleared our cache in and if we cleared
it in this transaction just say we're all setup and carry on.  This survives
xfstests and stress.sh.

The inode cache will continue to use the normal csum infrastructure since it
only gets written once and there will be no more modifications to the fs tree in
a transaction commit.
Signed-off-by: NJosef Bacik <josef@redhat.com>

I noticed while running xfstests 83 that if we didn't have enough space to
delete our inode the orphan cleanup would just loop.  This is because it keeps
finding the same orphan item and keeps trying to kill it but can't because we
don't get an error back from iput for deleting the inode.  So keep track of the
last guy we tried to kill, if it's the same as the one we're trying to kill
currently we know we are having problems and can just error out.  I don't have a
way to test this so look hard and make sure it's right.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Xfstests 83 really stresses our ENOSPC since it uses a 100mb fs which ends up
with the mixed block group stuff.  Because of this we can run into a situation
where we don't have enough space to delete inodes, or even worse we can't free
the inodes when we next mount the fs which causes the orphan code to lose its
mind.  So if we fail to make our reservation, steal from the global reserve.
The global reserve will end up taking up the entire rest of the free space on
the fs in this worst case so there really is no other option.  With this patch
test 83 doesn't freak out.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

In fixing how we deal with bad inodes, we had a regression in the orphan cleanup
code, since it expects to get a bad inode back.  So fix it to deal with getting
-ESTALE back by deleting the orphan item manually and moving on.  Thanks,
Reported-by: NSimon Kirby <sim@hostway.ca>
Signed-off-by: NJosef Bacik <josef@redhat.com>

Johannes pointed out we were allocating only kernel pages for doing writes,
which is kind of a big deal if you are on 32bit and have more than a gig of ram.
So fix our allocations to use the mapping's gfp but still clear __GFP_FS so we
don't re-enter.  Thanks,
Reported-by: NJohannes Weiner <jweiner@redhat.com>
Signed-off-by: NJosef Bacik <josef@redhat.com>

The only thing that we need to have a trans handle for is in
reserve_metadata_bytes and thats to know how much flushing we can do.  So
instead of passing it around, just check current->journal_info for a
trans_handle so we know if we can commit a transaction to try and free up space
or not.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Since free space inodes now use normal checksumming we need to make sure to
account for their metadata use.  So reserve metadata space, and then if we fail
to write out the metadata we can just release it, otherwise it will be freed up
when the io completes.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

While debugging a different issue I noticed that we were always reserving space
when we tried to use our truncate block rsv's.  This is because they didn't have
a ->size value, so use_block_rsv just assumes there is nothing reserved and it
does a reserve_metadata_bytes.  This is because btrfs_check_block_rsv() doesn't
actually add to the size of the block rsv.  That seems to be the right thing to
do so set ->size to the minimum truncate size we need, since we will always only
refill to that size anyway, and this way everything works out correctly.
Signed-off-by: NJosef Bacik <josef@redhat.com>

If you run xfstest 224 it you will get lots of messages about not being able to
delete inodes and that they will be cleaned up next mount.  This is because
btrfs_block_rsv_check was not calling reserve_metadata_bytes with the ability to
flush, so if there was not enough space, it simply failed.  But in truncate and
evict case we could easily flush space to try and get enough space to do our
work, so make btrfs_block_rsv_check take a flush argument to pass down to
reserve_metadata_bytes.  Now xfstests 224 runs fine without all those
complaints.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

With btrfs_truncate_inode_items we always return if we have to go to another
leaf, which makes us do our reservation again.  This means we will only ever
modify one leaf at a time, so we only need 1 items worth of slack space.  Also,
since we are deleting we will not be creating nodes as we go down, if anything
we'll be free'ing them as we merge them together, so make a different
calculation for truncate which will only have the worst case useage of COW'ing
the entire path down to the leaf.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Currently we're starting and stopping a transaction for no real reason, so kill
that and just reserve enough space as if we can truncate all in one transaction.
Also use btrfs_block_rsv_check() for our reserve to minimize the amount of space
we may have to allocate for our slack space.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>