The identifier for data.h's include guard was brought over from an old
file and still had the old name. Update it to reflect it's use in data,
not filerw.
Signed-off-by: Zach Brown <zab@versity.com>
When we added the kernelcompat layer around the old and new readdir
interfaces there was some confusion in the old readdir interface filldir
arguments. We were passing in our scoutfs dent item struct pointer
instead of the filldir callback buf pointer. This prevented readdir
from working in older kernels because filldir would immediately see a
corrupt buf and return an error.
This renames the emit compat macro arguments to make them consistent
with the other calls and readdir now provides the correct pointer to the
emit wrapper.
Signed-off-by: Zach Brown <zab@versity.com>
The radix block next bit search could return a spurious -ENOENT if it
ran out of references in a parent block further down the tree. It needs
to bubble up to try the next ref in its parent so that it keeps
performing a depth-first search of the entire tree.
This lead to an assertion being tripped in _radix_merge. Getting an
early -ENOENT caused it to start searching from 0 again. When it's
iterating over a read-only input it could find the same leaf and try to
clear source bits that were already cleared.
Signed-off-by: Zach Brown <zab@versity.com>
Add a bit more detail to the radix merge trace. It was missing the
input block and leaf bit. Also use abbreviations of the fields in the
trace output so that it's slightly less enormous.
Signed-off-by: Zach Brown <zab@versity.com>
The seq portion of radix block references is intended to differentiate
versions of a given block location over time. The current method of
incrementing the existing value as the block is dirtied is risky. It
means that every lineage of a block has the same sequence number
progression. Different trees referencing the same block over time could
get confused. It's more robust to have large random numbers. The
collision window is then evenly distributed over the 64bit space rather
than being bunched up all in in the initial seq values.
Signed-off-by: Zach Brown <zab@versity.com>
When we're merging bits that are set in a read-only input tree then we
can't try to merge more bits than exist in the input tree. That'll
cause us to loop around and double-free bits.
Signed-off-by: Zach Brown <zab@versity.com>
We were using bitmap_xor() to set and clear blocks of allocator bits at
a time. bitmap_xor() is a ternary function with two const input
pointers and we were providing the changing destination as a const input
pointer. That doesn't seem wise.
Signed-off-by: Zach Brown <zab@versity.com>
An incorrect warning condition was added as fallocate was implemented.
It tried to warn against trying to read from the staging ioctl. But the
staging boolean is set on the inode when the staging ioctl has the inode
mutex. It protects against writes, but page reading doesn't use the
mutex. It's perfectly acceptable for reads to be attempted while the
staging ioctl is busy. We rely on it for a large read to consume
staging being written.
The warning caused reads to fail while the stager ioctl was working.
Typically this would hit read-ahead and just force sync reads. But it
could hit sync reads and cause EIO.
Signed-off-by: Zach Brown <zab@versity.com>
Add specific error messages for failures that can happen as the server
commits log trees from the client. These are severe enough that we'd
like to know about them.
Signed-off-by: Zach Brown <zab@versity.com>
Back in ancient LSM times these functions to read and write the super
block reused the bio functions that LSM segment IO used. Each IO would
be performed with privately allocated pages and bios.
When we got rid of the LSM code we got rid of the bio functions. It was
quick and easy to transition super read/write to use buffer_heads. This
introduced sharing of the super's buffer_head between readers and
writers. First we saw concurrent readers being confused by the uptodate
bit and added a bunch of complexity to coordinate use of the uptodate
bit.
Now we're seeing the writer copy its super for writing into the buffer
that readers are using, causing crc failures on read. Let's not use
buffer_heads anymore (always good advice).
We added quick block functions to read and write small blocks with
private pages and bios. Use those here to read and write the super so
that readers and writers operate on their own buffers again.
Signed-off-by: Zach Brown <zab@versity.com>
Add two quick functions which perform IO on small fixed size 4K blocks
to or from the caller's buffer with privately allocated pages and bios.
Callers have no interaction with each other. This matches the behaviour
expected by callers of scoutfs_read_super and _write_super.
Signed-off-by: Zach Brown <zab@versity.com>
We miscalculated the length of extents to create when initializing
offline extents for setattr_more. We were clamping the extent length in
each packed extent item by the full size of the offline extent, ignoring
the iblock position that we were starting from.
Signed-off-by: Zach Brown <zab@versity.com>
With the introduction of packed extent items the setattr_more ioctl had
to be careful not to try and dirty all the extent items in one
transaction. But it pulled the extent creation call up to high and was
doing it before some argument checks that were done after the inode was
refreshed by acquiring its lock. This moves the extent creation to be
done after the args are verified for the inode.
Signed-off-by: Zach Brown <zab@versity.com>
Don't return -ENOENT from fiemap on a file with no extents. The
operation is supposed to succeed with no extents.
Signed-off-by: Zach Brown <zab@versity.com>
The setattr_more ioctl has its own helper for creating uninitialized
extents when we know that there can't be any other existing extents. We
don't have to worry about freeing blocks they might have referenced.
This helper forgot to actually store the modified extents back into
packed extent items after setting extents offline.
Signed-off-by: Zach Brown <zab@versity.com>
Add a bit more tracing to stage, release, and unwritten extent
conversion so we can get a bit more visibility into the threads staging
and releasing.
Signed-off-by: Zach Brown <zab@versity.com>
We need to invalidate old stale blocks we encounter when reading old
bloom block references written by other nodes. This is the same
consistency mechanism used by btree blocks.
Signed-off-by: Zach Brown <zab@versity.com>
A quick update of the comment describing the forest's use of the bloom
filter block. It used to be a tree of bloom filter items.
Signed-off-by: Zach Brown <zab@versity.com>
Remove a bunch of unused counters which have accumulated over time as
we've worked on the code and forgotten to remove counters.
Signed-off-by: Zach Brown <zab@versity.com>
Forest item iteration allocates iterator positions for each tree root
it reads from. The postorder destruction of the iterator nodes wasn't
quite right because we were balancing the nodes as they were freed.
That can change parent/child relationships and cause postorder iteration
to skip some nodes, leaking memory. It would have worked if we just
freed the nodes without using rb_erase to balance.
The fix is to actually iterate over the rbnodes while using the destroy
helper which rebalances as it frees.
Signed-off-by: Zach Brown <zab@versity.com>
The conversion to reading the super with buffer_head IO caused racing
readers to risk spurious errors. Clearing uptodate to force device
access could race with a current waking reader. They could wake and
find uptodate cleared and think that an IO error had occurred.
The buffer_head functions generally require higher level serialization
of this kind of use of the uptodate bit. We use bh_private as a counter
to ensure that we don't clear uptodate while there are active readers.
We then also use a private buffer_head bit to satisfy batches of waiting
readers with each IO.
Signed-off-by: Zach Brown <zab@versity.com>
Updating the _first tracking in leaf bits was pretty confusing because
we tried to mashing all the tracking updates from all leaf modifications
into one shared code path.
It had a bug where merging would advance _first tracking by the number
of bits merged in the leaf rather than the number of contiguous set bits
after the new first. This lead to allocation failures eventually as
_first was after actual set bits in the leaf.
This fixes that by moving _first tracking updates into the leaf callers
that modify bits and to the parent ref updating code.
In the process we also fix little bugs in the support code that were
found by the radix block consistency checking.
Signed-off-by: Zach Brown <zab@versity.com>
The client lock code forgot to call into the forest to clear its
per-lock tracking before freeing the lock. This would result in a slow
memory leak over time as locks were reclaimed by memory pressure. It
shouldn't have affected consistency.
Signed-off-by: Zach Brown <zab@versity.com>
The block end_io path could lose wakeups. Both the bio submission
task and a bio's end_io completion could see an io_count > 1 and neither
would set the block uptodate before dropping their io_count and waking.
It got into this mess because readers were waiting for io_count to drop
to 0. We add a io_busy bit which indicates that io is still in flight
which waiters now wait for. This gives the final io_count drop a chance
to do work before clearing io_busy and dropping their reference before
waking.
Signed-off-by: Zach Brown <zab@versity.com>
The first pass at the radix allocator wasn't paying a lot of attention
to the allocation cursors.
This more carefully manages them. They're only advanced after
allocating. Previously the metadata alloc cursor was advanced as it
searched through leaves that it might allocate from. We test for
wrapping past the specific final allocatable bit, rather than the limit
of what the radix height can store. This required pushing knoweldge of
metadata or data allocs down through some of the code paths.
Signed-off-by: Zach Brown <zab@versity.com>
Reclaim freed metadata blocks in the server by merging the stable freed
tree into the allocator as a commit opens and we can trust that the
stable version of the freed allocator in the super is a strict subset of
the allocator's dirty freed tree.
Signed-off-by: Zach Brown <zab@versity.com>
Server processing paths had open coded management of holding and
applying transactions. Refactor that into hold_commit() and
apply_commit() helpers. It makes the code a whole lot clearer and gives
us a place in hold_commit() to add code that needs to be run before
anything is modified in a commit on the server.
Signed-off-by: Zach Brown <zab@versity.com>
The server now consistently reclaims free space in client allocator
radix trees. It merges the client's freed trees as the client
opens a new transaction. And it reclaims all the client's trees
when it is removed.
Signed-off-by: Zach Brown <zab@versity.com>
The conversion of the btree to using allocators missed freeing blocks in
two places. As we overwrite dirty new blocks we weren't freeing the old
stable block as its reference was overwritten. And as we removed the
final item in the tree we weren't freeing the final empty block as it's
removed.
Signed-off-by: Zach Brown <zab@versity.com>
The removal of extent allocators in the server removed the tracking of
total free blocks in the system as extents were allocated and freed.
This restores tracking of total free blocks by observing the difference
in each allocator's sm_total count as a new version is stored during a
commit on the server.
We change the single free_blocks counter in the super to separate counts
of free metadata and data blocks to reflect the metadata and data
allocators. The statfs net command is updated.
Signed-off-by: Zach Brown <zab@versity.com>
Now that we have the allocators that use radix blocks we can remove all
the code that was using btree items to store free block bitmaps.
Signed-off-by: Zach Brown <zab@versity.com>
Convert metadata block and file data extent allocations to use the radix
allocator.
Most of this is simple transitions between types and calls. The server
no longer has to initialize blocks because mkfs can write a single
radix parent block with fully set parent refs to initialize a full
radix. We remove the code and fields that were responsible for adding
uninitialized data and metadata.
The rest of the unused block allocator code is only ifdefed out. It'll
be removed in a separate patch to reduce noise here.
Signed-off-by: Zach Brown <zab@versity.com>
Add the allocator that uses bits stored in the leaves of a cow radix.
It'll replace two metadata and data allocators that were previously
storing allocation bitmap fragments in btree items.
Signed-off-by: Zach Brown <zab@versity.com>
Add a call to move a block's location in the cache without failure. The
radix allocator is going to use this to dirty radix blocks while making
atomic changes to multipls paths through multiple radix trees.
Signed-off-by: Zach Brown <zab@versity.com>
Switch the block cache from indexing blocks in a radix tree to using an
rbtree. We lose the RCU lookups but we gain being able to move blocks
around in the cache without allocation failure. And we no longer have
the problem of not being able to index large blocks with a 32bit long
radix key.
Signed-off-by: Zach Brown <zab@versity.com>
Add functions for callers to maintain a visited bit in cached blocks.
The radix allocator is going to use this to count the number of clean
blocks it sees across paths through the radix which can share parent
blocks.
Signed-off-by: Zach Brown <zab@versity.com>
The bloom block reading code forgot to test if the read block was stale.
It would trust whatever it read. Now the read when building up roots to
use can return stale and retry.
Signed-off-by: Zach Brown <zab@versity.com>
Update the summary of the benefit we get from concurrent per-mount
commits. Instead of describing it specifically in terms of LSM we
abstract it out a bit to make it also true of writing per-mount log
btrees.
Signed-off-by: Zach Brown <zab@versity.com>
The forest item iterator was missing items. Picture the following
search pattern:
- find a candidate item to return in a root
- ignore a greater candidate to return in another root
- find the first candidates item's deletion in another root
The problem was that finding the deletion item didn't reset the notion
that we'd found a key. The next item from the second root was never
used because the found key wasn't reset and that root had already
searched past the found key.
The core architectural problem is that iteration can't examine each item
only once given that keys and deletions can be randomly distributed
across the roots.
The most efficient way to solve the problem is to really sort the
iteration positions in each root and then walk those in order. We
get the right answer and pay some data structure overhead to perform
the minimum number of btree searches.
Signed-off-by: Zach Brown <zab@versity.com>
As we shut down the transaction tries to destroy any remaining dirty
blocks in its writer context. The block writer context was only
initialized by the client as it asked the server for the log trees.
This makes sure the writer is always initialized.
Signed-off-by: Zach Brown <zab@versity.com>
The xattr code had a static defintion of the largest part item that it
would create. Change it to be a function of the largest fs item
value that can be created and clean up the code a bit in the process.
Signed-off-by: Zach Brown <zab@versity.com>
We are no longer storing individual extents in items from multiple
places and indexed in multiple ways. We can remove this extent support
code.
Signed-off-by: Zach Brown <zab@versity.com>
The btree forest item storage doesn't have as much item granular state
as the item cache did. The item cache could tell if a cached item was
populated from persistent storage or was created in memory. It could
simply remove created items rather than leaving behind a deletion item.
The cached btree blocks in the btree forest item storage mechanism can't
do this. It has to create deletion items when deleting newly created
items because it doesn't know if the item already exists in the
persistent record or not.
This created a problem with the extent storage we were using. The
individual extent items were stored with a key set to the last logical
block of their extent. As extents grew or shrank they often were
deleted and created at different key values during a transaction. In
the btree forest log trees this left a huge stream of deletion items
beind, one for every previous version of the extent. Then searches for
an extent covering a block would have to skip over all these deleted
items before hitting the current stored extent.
Streaming writes would operate on O(n) for every extent operation. It
got to be out of hand. This large change solves the problem by using
more coarse and stable item storage to track free blocks and blocks
mapped into file data.
For file data we now have large packed extent items which store packed
representations of all the logical mappings of a fixed region of a file.
The data code has loading and storage functions which transfer that
persistent version to and from the version that is modified in memory.
Free blocks are stored in bitmaps that are similarly efficiently packed
into fixed size items. The client is no longer working with free extent
items managed by the forest, it's working with free block bitmap btrees
directly. It needs access to the client's metadata block allocator and
block write contexts so we move those two out of the forest code and up
into the transaction.
Previously the client and server would exchange extents with network
messages. Now the roots of the btrees that store the free block bitmap
items are communicated along with the roots of the other trees involved
in a transaction. The client doesn't need to send free extents back to
the server so we can remove those tasks and rpcs.
The server no longer has to manage free extents. It transfers block
bitmap items between trees around commits. All of its extent
manipulation can be removed.
The item size portion of transaction item counts are removed because
we're not using that level of granularity now that metadata transactions
are dirty btree blocks instead of dirty items we pack into fixed sized
segments.
Signed-off-by: Zach Brown <zab@versity.com>
We need a way to compare two items in different log btrees and learn
which is the most recent. Each time we grant a new write lock we give
it a larger write version. Items store the version of the lock they're
written under. Readers can now easily see which item is newer.
This is a trivial initial implementation which is not consistent across
unmount or server failover. We'll need to recover the greatest
write_version from locks during recovery and from log trees as the
server starts up.
Signed-off-by: Zach Brown <zab@versity.com>
