We track two conditions to decide if we should sleep while waiting for more
delayed refs, the number of delayed refs (num_refs) and the first entry in
the list of blockers (first_seq).

When we suspect staleness, we save num_refs and do one more cycle. If
nothing changes, we then save first_seq for later comparison and do
wait_event. We ought to save first_seq the very same moment we're saving
num_refs. Otherwise we cannot be sure that nothing has changed and we might
start waiting when we shouldn't, which could lead to starvation.
Signed-off-by: NJan Schmidt <list.btrfs@jan-o-sch.net>

Miao pointed this out while I was working on an orphan problem that messing
with a bitfield where different ranges are protected by different locks
doesn't work out right.  Turns out we've been doing this forever where we
have different parts of the bit field protected by either no lock at all or
different locks which could cause all sorts of weird problems including the
issue I was hitting.  So instead make a runtime_flags thing that we use the
normal bit operations on that are all atomic so we can keep having our
no/different locking for the different flags and then make force_compress
it's own thing so it can be treated normally.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Three callers of btrfs_free_tree_block or btrfs_alloc_tree_block passed
parameter for_cow = 1. In fact, these two functions should never mark
their tree modification operations as for_cow, because they can change
the number of blocks referenced by a tree.

Hence, we remove the extra for_cow parameter from these functions and
make them pass a zero down.
Signed-off-by: NJan Schmidt <list.btrfs@jan-o-sch.net>

It confuses Smatch that we use two names for the same lock.  Plus the
shorter name is nicer.  This doesn't change how the code works, it's
just a cleanup.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>

verify_parent_transid needs to lock the extent range to make
sure no IO is underway, and so it can safely clear the
uptodate bits if our checks fail.

But, a few callers are using it with spinlocks held.  Most
of the time, the generation numbers are going to match, and
we don't want to switch to a blocking lock just for the error
case.  This adds an atomic flag to verify_parent_transid,
and changes it to return EAGAIN if it needs to block to
properly verifiy things.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

may_commit_transaction() calls
        spin_lock(&space_info->lock);
        spin_lock(&delayed_rsv->lock);
and update_global_block_rsv() calls
        spin_lock(&block_rsv->lock);
        spin_lock(&sinfo->lock);

Lockdep complains about this at run time.
Everywhere except in update_global_block_rsv(), the space_info lock is
the outer lock, therefore the locking order in update_global_block_rsv()
is changed.
Signed-off-by: NStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

It is basically a good thing if we are interruptible when waiting for
free space, but the generality in which it is implemented currently
leads to system calls being interruptible that are not documented this
way. For example git can't handle interrupted unlink(), leading to
corrupt repos under space pressure.
Instead we raise the bar to only be interruptible by SIGKILL.
Thanks to David Sterba for suggesting this.
Signed-off-by: NArne Jansen <sensille@gmx.net>

The caller expects this function to return with the lock held and
releases it immediately on error.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>

A user reported that booting his box up with btrfs root on 3.4 was way
slower than on 3.3 because I removed the ideal caching code.  It turns out
that we don't load the free space cache if we're in a commit for deadlock
reasons, but since we're reading the cache and it hasn't changed yet we are
safe reading the inode and free space item from the commit root, so do that
and remove all of the deadlock checks so we don't unnecessarily skip loading
the free space cache.  The user reported this fixed the slowness.  Thanks,
Tested-by: NCalvin Walton <calvin.walton@kepstin.ca>
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This fixes a regression introduced by fc67c450.  spin_is_locked() always
returns 0 on UP kernels, which caused assert in get_restripe_target() to
be fired on every call from btrfs_reduce_alloc_profile() on UP systems.
Remove it completely for now, it's not clear if it's going to be needed
in future.
Reported-by: NBobby Powers <bobbypowers@gmail.com>
Reported-by: NMitch Harder <mitch.harder@sabayonlinux.org>
Tested-by: NMitch Harder <mitch.harder@sabayonlinux.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This reverts commit 5500cdbe.

We've had a number of complaints of early enospc that bisect down
to this patch.  We'll hae to fix the reservations differently.

CC: stable@kernel.org
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This deadlock comes from xfstests 251.

We'll hold the chunk_mutex throughout the whole of a chunk allocation.
But if we find that we've used up system chunk space, we need to allocate a
new system chunk, but this will lead to a recursion of chunk allocation and end
up with a deadlock on chunk_mutex.
So instead we need to allocate the system chunk first if we find we're in ENOSPC.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

o For space info, the type of space info is useful for debug.
o For transaction handle, its transid is useful.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Currently if we don't have enough space allocated we go ahead and loop
though devices in the hopes of finding enough space for a chunk of the
*same* type as the one we are trying to relocate.  The problem with that
is that if we are trying to restripe the chunk its target type can be
more relaxed than the current one (eg require less devices or less
space).  So, when restriping, run checks against the target profile
instead of the current one.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Add __get_block_group_index() helper to be able to derive block group
index from an arbitary set of flags.  Implement get_block_group_index()
in terms of it.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Add get_restripe_target() helper and switch everybody to use it.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Header file is not a good place to define functions.  This also moves a
call to alloc_profile_is_valid() down the stack and removes a redundant
check from __btrfs_alloc_chunk() - alloc_profile_is_valid() takes it
into account.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

"0" is a valid value for an on-disk chunk profile, but it is not a valid
extended profile.  (We have a separate bit for single chunks in extended
case)

Also rename it to alloc_profile_is_valid() for clarity.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Add functions to abstract the conversion between chunk and extended
allocation profile formats and switch everybody to use them.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

This has been causing a lot of confusion for quite a while now and a lot
of users were surprised by this (some of them were even stuck in a
ENOSPC situation which they couldn't easily get out of).  The addition
of restriper gives users a clear choice between raid0 and drive concat
setup so there's absolutely no excuse for us to keep doing this.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Because btrfs cow's we can end up with extent buffers that are no longer
necessary just sitting around in memory.  So instead of evicting these pages, we
could end up evicting things we actually care about.  Thus we have
free_extent_buffer_stale for use when we are freeing tree blocks.  This will
make it so that the ref for the eb being in the radix tree is dropped as soon as
possible and then is freed when the refcount hits 0 instead of waiting to be
released by releasepage.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

We have been passing nothing but (u64)-1 to find_free_extent for search_end in
all of the callers, so it's completely useless, and we've always been passing 0
in as search_start, so just remove them as function arguments and move
search_start into find_free_extent.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

This is a relic from before we had the disk space cache and it was to make
bootup times when you had btrfs as root not be so damned slow.  Now that we have
the disk space cache this isn't a problem anymore and really having this code
casues uneeded fragmentation and complexity, so just remove it.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

 btrfs currently handles most errors with BUG_ON. This patch is a work-in-
 progress but aims to handle most errors other than internal logic
 errors and ENOMEM more gracefully.

 This iteration prevents most crashes but can run into lockups with
 the page lock on occasion when the timing "works out."
Signed-off-by: NJeff Mahoney <jeffm@suse.com>

Commit cb1b69f4 (Btrfs: forced readonly when btrfs_drop_snapshot() fails)
made btrfs_drop_snapshot return void because there were no callers checking
the return value. That is the wrong order to handle error propogation since
the caller will have no idea that an error has occured and continue on
as if nothing went wrong.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>

Signed-off-by: NJeff Mahoney <jeffm@suse.com>

 __find_space_info can return NULL but we don't check it before calling
 dump_space_info().
Signed-off-by: NJeff Mahoney <jeffm@suse.com>

The enospc tracing code added some interesting uses of
u64 pointer casts.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

When doing IO with large amounts of data fragmentation, the global block
reserve calulations are too low.  This increases them to avoid
ENOSPC crashes.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

When overcommitting, we should check the sum of pinned space and
bytes for delayed item.
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>

A user reported a bug of btrfs's trim, that is we will trim 0 bytes
after a device delete.

The reproducer:

$ mkfs.btrfs disk1
$ mkfs.btrfs disk2
$ mount disk1 /mnt
$ fstrim -v /mnt
$ btrfs device add disk2 /mnt
$ btrfs device del disk1 /mnt
$ fstrim -v /mnt

This is because after we delete the device, the block group may start from
a non-zero place, which will confuse trim to discard nothing.
Reported-by: NLutz Euler <lutz.euler@freenet.de>
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>

When we did sysbench test for inline files, enospc error happened easily though
there was lots of free disk space which could be allocated for new chunks.

Reproduce steps:
 # mkfs.btrfs -b $((2 * 1024 * 1024 * 1024)) <test partition>
 # mount <test partition> /mnt
 # ulimit -n 102400
 # cd /mnt
 # sysbench --num-threads=1 --test=fileio --file-num=81920 \
 > --file-total-size=80M --file-block-size=1K --file-io-mode=sync \
 > --file-test-mode=seqwr prepare
 # sysbench --num-threads=1 --test=fileio --file-num=81920 \
 > --file-total-size=80M --file-block-size=1K --file-io-mode=sync \
 > --file-test-mode=seqwr run
 <soon later, BUG_ON() was triggered by enospc error>

The reason of this bug is:
Now, we can reserve space which is larger than the free space in the chunks if
we have enough free disk space which can be used for new chunks. By this way,
the space allocator should allocate a new chunk by force if there is no free
space in the free space cache. But there are two wrong checks which break this
operation.

One is
	if (ret == -ENOSPC && num_bytes > min_alloc_size)
in btrfs_reserve_extent(), it is wrong, we should try to allocate a new chunk
even we fail to allocate free space by minimum allocable size.

The other is
	if (space_info->force_alloc)
		force = space_info->force_alloc;
in do_chunk_alloc(). It makes the allocator ignore CHUNK_ALLOC_FORCE If someone
sets ->force_alloc to CHUNK_ALLOC_LIMITED, and makes the enospc error happen.

Fix these two wrong checks. Especially the second one, we fix it by changing
the value of CHUNK_ALLOC_LIMITED and CHUNK_ALLOC_FORCE, and make
CHUNK_ALLOC_FORCE greater than CHUNK_ALLOC_LIMITED since CHUNK_ALLOC_FORCE has
higher priority. And if the value which is passed in by the caller is greater
than ->force_alloc, use the passed value.
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

system chunks by default are very small.  This makes them slightly
larger and also fixes the conditional checks to make sure we don't
allocate a billion of them at once.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

I was using i_mutex for this, but we're getting bogus lockdep warnings by doing
that and theres no real way to get rid of those, so just stop using i_mutex to
protect delalloc metadata reservations and use a delalloc mutex instead.  This
shouldn't be contended often at all, only if you are writing and mmap writing to
the file at the same time.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

This in addition to a script in my btrfs-tracing tree will help track down space
leaks when we're getting space left over in block groups on umount.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

I used these tracepoints when figuring out what the cluster stuff was doing, so
add them to mainline in case we need to profile this stuff again.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Profile changing is done by launching a balance with
BTRFS_BALANCE_CONVERT bits set and target fields of respective
btrfs_balance_args structs initialized.  Profile reducing code in this
case will pick restriper's target profile if it's available instead of
doing a blind reduce.  If target profile is not yet available it goes
back to a plain reduce.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Every caller of do_chunk_alloc() feeds it the reduced allocation
profile, so stop trying to reduce it one more time.  Instead check the
validity of the passed profile.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Currently when new chunks are created respective avail_alloc_bits field
is updated to reflect profiles of all chunks present in the system.
However when chunks are removed profile bits are never cleared.

This patch clears profile bit of respective avail_alloc_bits field when
the last chunk with that profile is removed.  Restriper needs this to
properly operate when "downgrading".
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Right now on-disk BTRFS_BLOCK_GROUP_* profile bits are used for
avail_{data,metadata,system}_alloc_bits fields, which gather info about
available allocation profiles in the FS.  When chunk is created or read
from disk, its profile is OR'ed with the corresponding avail_alloc_bits
field.  Since SINGLE is denoted by 0 in the on-disk format, currently
there is no way to tell when such chunks become avaialble.  Restriper
needs that information, so add a separate bit for SINGLE profile.

This bit is going to be in-memory only, it should never be written out
to disk, so it's not a disk format change.  However to avoid remappings
in future, reserve corresponding on-disk bit.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>