People have been running into a warning when loading space cache because the
page is already mapped when trying to read in a bitmap.  The way we read in
entries and pages is kind of convoluted, so fix it so that io_ctl_read_entry
maps the entries if it needs to, and if it hits the end of the page it simply
unmaps the page.  That way we can unconditionally unmap the io_ctl before
reading in the bitmap and we should stop hitting these warnings.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

We no longer use the orphan block rsv for holding the reservation for truncating
the inode, so instead use the global block rsv and check to make sure it has
enough space for us to truncate the space.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

btrfs_remove_free_space needs to make sure to set ret back to a
valid return value after setting it to EAGAIN, otherwise we return
it to the callers.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

I noticed we had a little bit of latency when writing out the space cache
inodes.  It's because we flush it before we write anything in case we have dirty
pages already there.  This doesn't matter though since we're just going to
overwrite the space, and there really shouldn't be any dirty pages anyway.  This
makes some of my tests run a little bit faster.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.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>

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>

We need to check the return value of filemap_write_and_wait in the space cache
writeout code.  Also don't set the inode's generation until we're sure nothing
else is going to fail.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

In writing and reading the space cache we have one big loop that keeps track of
which page we are on and then a bunch of sizeable loops underneath this big loop
to try and read/write out properly.  Especially in the write case this makes
things hugely complicated and hard to follow, and makes our error checking and
recovery equally as complex.  So add a io_ctl struct with a bunch of helpers to
keep track of the pages we have, where we are, if we have enough space etc.
This unifies how we deal with the pages we're writing and keeps all the messy
tracking internal.  This allows us to kill the big loops in both the read and
write case and makes reviewing and chaning the write and read paths much
simpler.  I've run xfstests and stress.sh on this code and it survives.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

I noticed a slight bug where we will not bother writing out the block group
cache's space cache if it's space tree is empty.  Since it could have a cluster
or pinned extents that need to be written out this is just not a valid test.
Thanks,
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>

In moving some enospc stuff around I noticed that when we unmount we are often
evicting the free space cache inodes before we do our last commit.  This isn't
bad, but it makes us constantly have to re-read the inodes back.  So instead
don't evict the cache until after we do our last commit, this will make things a
little less crappy and makes a future enospc change work properly.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

We are setting ins_len to 1 even tho we are just modifying an item that should
be there already.  This may cause the search stuff to split nodes on the way
down needelessly.  Set this to 0 since we aren't inserting anything.  Thanks,
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>

A user reported getting spammed when moving to 3.0 by this message.  Since we
switched to the normal checksumming infrastructure all old free space caches
will be wrong and need to be regenerated so people are likely to see this
message a lot, so ratelimit it so it doesn't fill up their logs and freak them
out.  Thanks,
Reported-by: NAndrew Lutomirski <luto@mit.edu>
Signed-off-by: NJosef Bacik <josef@redhat.com>

We have been using bytes_reserved for metadata reservations, which is wrong
since we use that to keep track of outstanding reservations from the allocator.
This resulted in us doing a lot of silly things to make sure we don't allocate a
bunch of metadata chunks since we never had a real view of how much space was
actually in use by metadata.

This passes Arne's enospc test and xfstests as well as my own enospc tests.
Hopefully this will get us moving in the right direction.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

While truncating free space cache, we forget to change trans->block_rsv
back to the original one, but leave it with the orphan_block_rsv, and
then with option inode_cache enable, it leads to countless warnings of
btrfs_alloc_free_block and btrfs_orphan_commit_root:

WARNING: at fs/btrfs/extent-tree.c:5711 btrfs_alloc_free_block+0x180/0x350 [btrfs]()
...
WARNING: at fs/btrfs/inode.c:2193 btrfs_orphan_commit_root+0xb0/0xc0 [btrfs]()
Signed-off-by: NLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Btrfs subtracted the size of the allocated space twice when it allocated
the space from the bitmap in the cluster, it broke the free space information
and led to oops finally.

And this patch also fixes the bug that ctl->free_space was subtracted
without lock.
Reported-by: NLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

grab_cache_page will use mapping_gfp_mask(), which for all inodes is set to
GFP_HIGHUSER_MOVABLE.  So instead use find_or_create_page in all cases where we
need GFP_NOFS so we don't deadlock.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

We used to store the checksums of the space cache directly in the space cache,
however that doesn't work out too well if we have more space than we can fit the
checksums into the first page.  So instead use the normal checksumming
infrastructure.  There were problems with doing this originally but those
problems don't exist now so this works out fine.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

A user reported this bug again where we have more bitmaps than we are supposed
to.  This is because we failed to load the free space cache, but don't update
the ctl->total_bitmaps counter when we remove entries from the tree.  This patch
fixes this problem and we should be good to go again.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Josef recently changed the free extent cache to look in
the block group cluster for any bitmaps before trying to
add a new bitmap for the same offset.  This avoids BUG_ON()s due
covering duplicate ranges.

But it didn't go quite far enough.  A given free range might span
between one or more bitmaps or free space entries.  The code has
looping to cover this, but it doesn't check for clustered bitmaps
every time.

This shuffles our gotos to check for a bitmap in the cluster
for every new bitmap entry we try to add.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

When merging my code into the integration test the second check for duplicate
entries got screwed up.  This patch fixes it by dropping ret2 and just using ret
for the return value, and checking if we got an error before adding the bitmap
to the local list.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

In cleaning up the clustering code I accidently introduced a regression by
adding bitmap entries to the cluster rb tree.  The problem is if we've maxed out
the number of bitmaps we can have for the block group we can only add free space
to the bitmaps, but since the bitmap is on the cluster we can't find it and we
try to create another one.  This would result in a panic because the total
bitmaps was bigger than the max bitmaps that were allowed.  This patch fixes
this by checking to see if we have a cluster, and then looking at the cluster rb
tree to see if it has a bitmap entry and if it does and that space belongs to
that bitmap, go ahead and add it to that bitmap.

I could hit this panic every time with an fs_mark test within a couple of
minutes.  With this patch I no longer hit the panic and fs_mark goes to
completion.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

When profiling the find cluster code it's hard to tell where we are spending our
time because the bitmap and non-bitmap functions get inlined by the compiler, so
make that not happen.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

If we are looking for a cluster in a particularly sparse or fragmented block
group, we will do a lot of looping through the free space tree looking for
various things, and if we need to look at bitmaps we will endup doing the whole
dance twice.  So instead add the bitmap entries to a temporary list so if we
have to do the bitmap search we can just look through the list of entries we've
found quickly instead of having to loop through the entire tree again.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

wrap checking of filesystem 'closing' flag and fix a few missing memory
barriers.
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

This makes the inode map cache default to off until we
fix the overflow problem when the free space crcs don't fit
inside a single page.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

The free space cache uses only one page for crcs right now,
which means we can't have a cache file bigger than the
crcs we can fit in the first page.  This adds a check to
enforce that restriction.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

If there are duplicate entries in the free space cache, discard the entire cache
and load it the old fashioned way.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>

Remove static and global declarations and/or definitions. Reduces size
of btrfs.ko by ~3.4kB.

  text    data     bss     dec     hex filename
402081    7464     200  409745   64091 btrfs.ko.base
398620    7144     200  405964   631cc btrfs.ko.remove-all
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

parameter tree root it's not used since commit
5f39d397 ("Btrfs: Create extent_buffer
interface for large blocksizes")
Signed-off-by: NDavid Sterba <dsterba@suse.cz>

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

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

If our space cache is wrong, we do the right thing and free up everything that
we loaded, however we don't reset the total_bitmaps counter or the thresholds or
anything.  So in btrfs_remove_free_space_cache make sure to call free_bitmap()
if it's a bitmap, this will keep us from panicing when we check to make sure we
don't have too many bitmaps.  Thanks,
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Since commit dc89e982, we've changed
to use a specific slab for alocation of free_space items.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This is similar to block group caching.

We dedicate a special inode in fs tree to save free ino cache.

At the very first time we create/delete a file after mount, the free ino
cache will be loaded from disk into memory. When the fs tree is commited,
the cache will be written back to disk.

To keep compatibility, we check the root generation against the generation
of the special inode when loading the cache, so the loading will fail
if the btrfs filesystem was mounted in an older kernel before.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

Extract out block group specific code from lookup_free_space_inode(),
create_free_space_inode(), load_free_space_cache() and
btrfs_write_out_cache(), so the code can be used to read/write
free ino cache.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>

Currently btrfs stores the highest objectid of the fs tree, and it always
returns (highest+1) inode number when we create a file, so inode numbers
won't be reclaimed when we delete files, so we'll run out of inode numbers
as we keep create/delete files in 32bits machines.

This fixes it, and it works similarly to how we cache free space in block
cgroups.

We start a kernel thread to read the file tree. By scanning inode items,
we know which chunks of inode numbers are free, and we cache them in
an rb-tree.

Because we are searching the commit root, we have to carefully handle the
cross-transaction case.

The rb-tree is a hybrid extent+bitmap tree, so if we have too many small
chunks of inode numbers, we'll use bitmaps. Initially we allow 16K ram
of extents, and a bitmap will be used if we exceed this threshold. The
extents threshold is adjusted in runtime.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>