Commit Graph
100 Commits
Author SHA1 Message Date
Zygo Blaxell d5a99c2f5e roots: don't share a RootFetcher between threads
If the send workaround is enabled, it is possible for two threads (a
thread running the crawl_new task, and a thread attempting to apply the
send workaround) to access the same RootFetcher object at the same time.
That never ends well.

Give each function its own BtrfsRootFetcher object.

Fixes: https://github.com/Zygo/bees/issues/250
Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-02-20 11:14:34 -05:00
Zygo Blaxell 849c071146 hash: flush the table more slowly
With SIGTERM and fast exit, the trickle writeback is less important.
We don't want to flood people's IO subsystems with continuous writes.
This really should be configurable at runtime.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-27 22:16:02 -05:00
Zygo Blaxell 85ff543695 test: simplify Makefile
Make can build dependencies in parallel, so let Make do that.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-27 22:16:02 -05:00
Zygo Blaxell 8147f80a5a src: bees-version.cc cleanups
Do rebuild bees-version.cc if libcrucible changes.
Don't rebuild bees-version.cc if it doesn't change.
Also use the standard suffix for new files.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-27 22:16:02 -05:00
Zygo Blaxell cbde237f79 src: simplify Makefile
Make can build dependencies in parallel, so let Make do that.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-27 22:16:02 -05:00
Zygo Blaxell 3b85fc8bc7 lib: drop version.cc entirely
crucible::VERSION doesn't make much sense now that libcrucible no
longer exists as a shared library.  Nothing ever referenced it, so
it can go away.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-27 22:16:02 -05:00
Zygo Blaxell 4df1b2c834 lib: simplify dependency generation
We don't need to run all the dependencies first, Make can do those in parallel.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-27 22:16:02 -05:00
Zygo Blaxell 495218104a fd: FS_IOC_SETFLAGS takes an int* argument not a long*
According to ioctl_iflags(2):

	The type of the argument given to the FS_IOC_GETFLAGS and
	FS_IOC_SETFLAGS  operations is int *, notwithstanding the
	implication in the kernel source file include/uapi/linux/fs.h
	that the argument is long *.

So this code doesn't work on be64 machines.

Also, Valgrind complains about it.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-27 22:16:02 -05:00
Zygo Blaxell e82ce3c06e fd: pwrite returns ssize_t not int
A subtle distinction, and not one that is particularly relevant to bees,
but it does make toolchains complain.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-27 22:16:02 -05:00
Zygo Blaxell bd336e81a6 fs: get rid of base class btrfs_ioctl_logical_ino_args
Another instance of the pattern where we derived a crucible class
from a btrfs struct.  Make it an automatic variable instead.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-27 22:16:02 -05:00
Zygo Blaxell ea17c89165 fs: remove duplicate BTRFS_COMPRESS_ definitions
This was fixed in

	7f660f50b lib: fs: stop using libbtrfs-dev helper functions to re-enable buffer length checks

but apparently some copies live on.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-27 22:16:02 -05:00
Zygo Blaxell ccd8dcd43f fiemap, fiewalk: drop dead example/test code
These tools are obsolete.  fiemap was a thin wrapper around FIEMAP,
but FIEMAP is not useful on btrfs.  fiewalk was a thin wrapper around
BtrfsExtentWalker, but development on BtrfsExtentWalker has been
abandoned.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-23 00:09:26 -05:00
Zygo Blaxell facf4121a6 context: remove the one call to operator vector<> method in BtrfsIoctlLogicalInoArgs
There's only one user of this method.  Open-code it so we can kill the
method in libcrucible.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-23 00:09:26 -05:00
Zygo Blaxell cbc76a7457 hash: don't spin when writes fail
When a hash table write fails, we skip over the write throttling because
we didn't report that we successfully wrote an extent.  This can be bad
if the filesystem is full and the allocations for writes are burning a
lot of CPU time searching for free space.

We also don't retry the write later on since we assume the extent is
clean after a write attempt whether it was successful or not, so the
extent might not be written out later when writes are possible again.

Check whether a hash extent is dirty, and always throttle after
attempting the write.

If a write fails, leave the extent dirty so we attempt to write it out
the next time flush cycles through the hash table.  During shutdown
this will reattempt each failing write once, after that the updated hash
table data will be dropped.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-23 00:09:26 -05:00
Zygo Blaxell 28ee2ae1a8 docs: fix broken link in options.md
Links in docs/ are relative to docs/, not the top level.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-23 00:08:54 -05:00
Zygo Blaxell d27621b779 main: catch exceptions and exit gracefully
Calling 'bees -m4' should not call 'std::terminate()', but it does.

Use catch_all instead.  It will still pass the exit value to return
from main.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-05 01:10:17 -05:00
Zygo Blaxell cb2c20ccc9 fs: get rid of base class btrfs_ioctl_same_extent_info
We only use BtrfsExtentInfo when it's exactly equivalent to the
base, so drop the derived class.

While we're here, fix BtrfsExtentSame::add so it uses a btrfs-compatible
uint64_t instead of an off_t.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-05 01:10:17 -05:00
Zygo Blaxell ded5bf0148 btrfs-tree: fix whitespace and const
Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-05 01:10:17 -05:00
Zygo Blaxell d5de012a17 btrfs-tree: translate item types for error messages
Look up the name when filling in the what() field for the exception.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-05 01:10:17 -05:00
Zygo Blaxell 66d1e8a89b btrfs-tree: add chunk items: length and type
Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-05 01:10:17 -05:00
Zygo Blaxell c327e0bb10 readahead: report the original size in BEESTOOLONG
BEESTOOLONG was always reporting a size of zero, and the offset of the
end of the readahead region.  Report the original size instead (and also
in BEESTRACE and BEESNOTE).

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-05 01:10:17 -05:00
Zygo Blaxell 9587c40677 docs: add crawl_again, drop crawl_restart
Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-05 01:10:17 -05:00
Zygo Blaxell a115587fad roots: fix extent lock failure handling
Drop the crawl_restart counter, it doesn't happen here (or anywhere else).

Add the crawl_again counter for extents that are restarted due to an
extent-level lock.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-05 01:10:17 -05:00
Zygo Blaxell af6ecbc69b trace: use pthread_setname wrapper
libcrucible can deal with the Linux kernel and/or libc's thread name
limitations.  No need to duplicate that work in bees.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-05 01:10:17 -05:00
Zygo Blaxell 563e584da4 task: use pthread_setname_np correctly
It turns out I've been using pthread_setname_np wrong the whole time:

 * on Linux, the thread name length is 15 characters.
   TASK_COMM_LEN is 16 bytes, and the last one is always 0.
   This is now hardcoded in many places and cannot be changed.

 * pthread_setname_np doesn't return -errno, so DIE_IF_MINUS_ERRNO
   was the wrong macro.  On the other hand, we never want to do anything
   differently when pthread_setname_np fails, so we never needed to
   check the return value.

Also, libc silently ignores attempts to set the thread name when it is too
long.  That's almost certainly a libc bug, but libc probably suppresses
the error result for the same reasons I ignore the error result.

Wrap the pthread_setname function with a C++ std::string overload that
truncates the argument at 15 characters, so we at least get the first
part of the task name in the thread name field.  Later commits can deal
with making the bees thread names shorter.

Also wrap pthread_getname for symmetry.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-05 01:10:17 -05:00
Zygo Blaxell c5889049f0 docs: remove duplicate (and wrong) default scan mode
The default scan mode is found in config.md.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2023-01-05 01:10:17 -05:00
Zygo Blaxell 64dab81e42 Merge github PR #148
Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-23 00:26:33 -05:00
Zygo Blaxell cfcdac110b context: don't count MultiLock waiting time in dedup_ms
This was inflating the dedup_ms statistic because it was counting all
the resolve time too.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-22 23:46:36 -05:00
Zygo Blaxell c3b664fea5 context: don't forget to retry locked extents
The caller of scan_forward has to stop advancing the BeesFileCrawl
position when an extent lock blocks a scan, so that it will resume
from the same position when the Task is scheduled again; otherwise,
bees simply skips over the extent and leave it incompletely deduped.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-22 23:46:36 -05:00
Zygo Blaxell bbcfd9daa6 roots: replace BEES_TRANSID_FACTOR with BEES_TRANSID_POLL_INTERVAL
Restart crawl_more (and update crawl roots and flush FD caches) every
time the transid changes, and only when the transid changes, but
not more often than a reasonable minimum poll interval.

Clean up the log message:  use the proper thread name and remove
the wildly inaccurate estimate of when crawl will resume.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:01 -05:00
Zygo Blaxell d6d3e1045e context: keep the resolve cache smaller
We don't need to cache 65536 extent maps, especially if each one
can have almost 700K references.

Valgrind's massif tool points to the extent map cache as a very
large memory allocator, but test runs with memcg disagree.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:01 -05:00
Zygo Blaxell d5d17cbe62 roots: run insert_new_crawl from within a Task
If we have loadavg targeting enabled, there may be no worker threads
available to respond to new subvols, so we should not bother updating
the subvols list.

Put insert_new_crawl into a Task so it only executes when a worker
is available.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:01 -05:00
Zygo Blaxell 48dd2a45fe docs: remove the line discussing 'max_transid' in recent scan mode
This makes the doc match the code again.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:01 -05:00
Zygo Blaxell 7267707687 roots: disable recent sorting by max_transid
On large filesystems where the min_transid of all subvols gets stuck at 0,
bees may lose the ability to effectively track recent data.  A secondary sort
by max_transid will allow scanning newer subvols that were created after bees
started running on the filesystem, but before bees completed the first scan
of all subvols.

On the other hand, the secondary sort does a reverse version of the
sequential scan mode, and the sequential scan mode is simply awful.

Disable it for now.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:01 -05:00
Zygo Blaxell 984ceeb2a5 docs: update documentation for new 'recent' scan mode
Also attempted to clarify the descriptions of the modes based on
feedback and questions from users over the years.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:01 -05:00
Zygo Blaxell 03f809bf22 roots: reimplement scan modes using virtual base and methods
Split each scan mode into two distinct phases:

    1.  A heavy discovery phase, where we search the entire filesystem
    for something (new items in subvol trees in this case).

    2.  A light consuming phase, where we fetch extents to dedupe
    from places that we found in the discovery phase.

Part 1 recomputes the subvol ordering every time there is a new transid.
For some scan modes this computation is quite expensive, far too costly
to pay for every extent, so we do it no more than once per transaction.

Part 2 is run every time a worker thread hits the crawl_more Task.
It simply pulls one extent from the first crawler off a sorted list,
removing the crawler from the list when the crawler runs out of data.

Part 1 creates a new structure and swaps it into place, while Part 2
continues to run using the previous strucuture.  Neither of these
need to block the other, so they don't.

The separate class and base pointer also make it easer to add new scan
modes that are not based on subvol trees or that don't use BeesCrawl.

While we're here, fix up some method visibility in BeesRoots.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:01 -05:00
Zygo Blaxell 0dca6f74b0 roots: remove duplicate default scan mode setting
Set the constructor's default scan mode to an invalid mode, so if we
change the default, we don't have to update two places.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:01 -05:00
Zygo Blaxell f5c4714a28 roots: add 'recent' crawl mode for a mix of new and old data
Crawl mode 3 'recent' prioritizes data from new updates to previously
scanned subvols over subvols that have not been completely scanned yet.
If no such new data exists, falls back to a variation of 'lockstep'
scan mode.

This enables us to keep up with new data as it arrives, a key weakness
of all the other scan modes, and worth violating our unwritten "no new
scan modes until we have extent-tree dedupe working" policy for.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:00 -05:00
Zygo Blaxell de96a38460 roots: emit "crawl finished" at the correct time
The correct time is when we set the deferred bit after a tree
search returns empty.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:00 -05:00
Zygo Blaxell 82c2b5bafe roots: improve thread status tracking messages
Don't dereference a shared_ptr inside a thread status function.

Do trace the crawl start events.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:00 -05:00
Zygo Blaxell d725f3c66c context: process PREALLOC extents synchronously in extent's Task worker
Inode-oriented scan workers must do all of their work sequentially,
so it's counterproductive to spawn a Task to do a background dedupe.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:00 -05:00
Zygo Blaxell 84f91af503 context: don't let multiple worker Tasks get stuck on a single extent or inode
When two Tasks attempt to lock the same extent, append the later Task
to the earlier Task's post-exec work queue.  This will guarantee that
all Tasks which attempt to manipulate the same extent will execute
sequentially, and free up threads to process other extents.

Similarly, if two scanner threads operate on the same inode, any dedupe
they perform will lock out other scanner threads in btrfs.  Avoid this
by serializing Task objects that reference the same file.

This does theoretically use an unbounded amount of memory, but in practice
a Task that encounters a contended extent or inode quickly stops spawning
new Tasks that might increase the queue size, and all Tasks that might
contend for the same lock(s) end up on a single FIFO queue.

Note that the scope of inode locks is intentionally global, i.e. when
an inode is locked, it locks every inode with the same number in every
subvol.  This avoids significant lock contention and task queue growth
when the same inode with the same file extents appear in snapshots.

Fixes: https://github.com/Zygo/bees/issues/158
Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:00 -05:00
Zygo Blaxell 31d26bcfc6 roots: organize scan workers by inode instead of extent
Split crawlers into two separate Tasks:

 1. a Task which locates the next inode with a new data extent.

 2. a Task which scans every new extent in that inode.

This simplifies some lock contention and execution ordering issues.
Files are read sequentially.  Workers dynamically scale up or
down as needed, without creating thousands of deferred Task objects.
Workers obtain inode locks for different inodes in btrfs, so they
can work in parallel instead of waiting for each other.

This change in behavior comes with new names for the worker Tasks:

        "crawl_master" is now "crawl_more", the singular Task which
        creates inode-scanning Tasks.

        "crawl_<subvol>" is now "crawl_<subvol>_<inode>".

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:00 -05:00
Zygo Blaxell e13c62084b roots: use scan mode 'independent' by default
Independent subvol scanners fairly consistently outperform either
of the correlated scan modes.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:00 -05:00
Zygo Blaxell 7cef1133be roots: use symbolic names for SCAN_MODEs
This was done on the development branch three years ago, and
has been creating annoying merge conflicts ever since.  Sync
up the branches so they have the same names for these.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:51:00 -05:00
Zygo Blaxell f98599407f roots: rework btrfs send workaround using btrfs-tree
Drop the cache since we no longer have to open a file every time we
check a subvol's status.

Also stop counting workaround events at the root level twice.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:59 -05:00
Zygo Blaxell 4d59939b07 btrfs-tree: introduce lightweight classes for btrfs tree search operations
btrfs-tree provides classes for low-level access to btrfs tree objects.

An item class is provided to decode polymorphic btrfs item fields.

Several tree classes provide forward and backward iteration over raw
object items at different tree levels.

A csum tree class provides convenient access to csums by bytenr,
supporting all current btrfs csum types.

Wrapper classes for inode and subvol items provide direct access to
btrfs metadata fields without clumsy stat() wrappers or ioctls.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:59 -05:00
Zygo Blaxell 24b904f002 seeker: backward searching template function
This template turns a forward search primitive (e.g. lower_bound, FIEMAP,
TREE_SEARCH_V2) into a backward search primitive.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:59 -05:00
Zygo Blaxell 23c16aa978 BeesFileRange: coalesce is not used, subtract was never implemented
Less dead code to maintain.  Also more Doxygen comments.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:59 -05:00
Zygo Blaxell 152e69a6d1 bytevector: validate length in get<T>()
Don't allow a pointer to T to be taken from a ByteVector that is not at
least sizeof(T) bytes long.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:58 -05:00
Zygo Blaxell 148cc03060 bytevector: do not deadlock in self-assignment
Not that this is a particularly useful use case, but it will lock up,
and it should not.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:58 -05:00
Zygo Blaxell b699325a77 bytevector: don't need _all_ of those mutexes
Methods that don't even look at the pointer don't need a mutex.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:58 -05:00
Zygo Blaxell a59d89ea81 bytevector: add some fugly mutexes
We are using ByteVectors from multiple threads in some cases.  Mostly
these are the status and progress threads which read the ByteVector
object references embedded in BEESNOTE macros.

Since it's not clear what the data race implications are, protect
the shared_ptr in ByteVector with a mutex for now.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:58 -05:00
Zygo Blaxell d1015b683f bytevector: add ostream output with hexdump
There is a hexdump template in fs.  Move hexdump to its own header,
then ByteVector can use it too.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:58 -05:00
Zygo Blaxell 9cdeb608f5 bees: drop the balance/logical workaround that has been disabled for two years
Kernels that needed the balance workaround frankly are too buggy
to run bees at all.  The workaround also makes the locking stories
around logical_ino calls and process exit complicated, so get rid of
it completely.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:58 -05:00
Zygo Blaxell 83a2b010e6 context: drop long-dead ExtentWalker code
At some point BtrfsExtentWalker will be fully deprecated and removed from
bees.  Might as well start with code that hasn't been built in 6 years.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:58 -05:00
Zygo Blaxell 31b2aa3c0d context: speed up orderly process termination
Quite often bees exceeds its service timeout for termination because
it is waiting for a loop embedded in a Task to finish some long-running
btrfs operation.  This can cause bees to be aborted by SIGKILL before
it can completely flush the hash table or save crawl state.

There are only two important things SIGTERM does when bees terminates:
 1.  Save crawl progress
 2.  Flush out the hash table

Everything else is automatically handled by the kernel when the process
is terminated by SIGKILL, so we don't have to bother doing it ourselves.
This can save considerable time at shutdown since we don't have to wait
for every thread to reach a point where it becomes idle, or force loops
to terminate by throwing exceptions, or check a condition every time we
access a pointer.  Instead, we need do only the things in the list
above, and then call _exit() to clean up everything else.

Hash table and crawl state writeback can happen in their background
threads instead of the foreground one.  Separate the "stop" method for
these classes into "stop_request" and "stop_wait" so that these writebacks
can run at the same time.

Deprecate and remove all references to the BeesHalt exception, and remove
several unnecessary checks for BeesContext::stop_requested.

Pause the task queue instead of cancelling it, which preserves the
crawl progress state and stops new Tasks from competing for iops and
CPU during writeback.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:58 -05:00
Zygo Blaxell 594ad1786d context: dump current load tracking stats
Dump the instantaneous load (last 5 seconds, extracted from load average)
and the computed target worker count (before rounding and truncation)
on the same status line as the task and worker thread count.

This should give better visibility into Task's thread count calculation
algorithm.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:57 -05:00
Zygo Blaxell b143664747 task: use exponential backoff algorithm to set thread count
Tasks are often running longer than 5 seconds (especially extents with
multiple references requiring copy operations), so the load tracking
algorithm needs to average several samples over a longer period of time
than 5 seconds.  If the sample period is 60 seconds, we end up recomputing
the original load average from current_load, so skip the rounding error
and use the original load average value.

Arguably the real fix is to break up the more complex extent operations
over several downstream Task objects, but that's a more significant
design change.

Tweak the attack and decay rates so that threads are started a little
more slowly, but still stopped rapidly when load spikes up.

Remove the hysteresis to provide support for load average targets
below 1, or with fractional components, with a PWM-like effect.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:57 -05:00
Zygo Blaxell a85ada3a49 task: export load tracking statistics
Provide an interface so that programs can monitor the Task load
average calculations.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:57 -05:00
Zygo Blaxell 46a38fe016 task: rescue post-exec queue on Task destruction
task1.append(task2) is supposed to run task2 after task1 is executed;
however, if task1 was just executed, and its last reference was owned by
a TaskConsumer, then task2 will be appended to a Task that will never
run again.

A similar problem arises in Exclusion, which can cause blocked tasks
to occasionally be dropped without executing them.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:57 -05:00
Zygo Blaxell 2aafa802a9 task: increase saved thread name length to 64
24 bytes seems a little low.  64 is a rounder (and more square) number.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:57 -05:00
Zygo Blaxell cdef59e2f3 task: add more Doxygen comments for PairLock
I need to remind myself why it's there, and not just std::lock.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:57 -05:00
Zygo Blaxell dc2dc8d08a task: delete the queue after deleting all of its children
This was resulting in an assertion failure later on if a queue was
being rescued from a deleted task with only one post-exec queue.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:57 -05:00
Zygo Blaxell 7873988dac task: add a pause() method as an alternative to cancel()
pause(true) stops the TaskMaster from processing any more Tasks,
but does not destroy any queued Tasks.

pause(false) re-enables Task processing.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:57 -05:00
Zygo Blaxell 3f740d6b2d task: simplify clear_queue
Simplify the loop in clear_queue because we can't be modifying a
queue while we are clearing it.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:56 -05:00
Zygo Blaxell c0a7533dd4 task: use const for current_consumer
The const version of this code has much more testing, but any
effect at run time is unlikely.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:56 -05:00
Zygo Blaxell 090fa39995 task: don't hold the mutex while disposing of pending Tasks
In the event that someday Barrier allows users to force execution of
its pending tasks prior to the destruction of the BarrierState object,
we'll be ready to submit those Tasks for execution without waiting for
the BarrierState mutex lock.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:56 -05:00
Zygo Blaxell 2f25f89067 task: get rid of separate Exclusion and ExclusionState
Exclusion was generating a new Task every time a lock was contended.
That results in thousands of empty Task objects which contain a single
Task item.

Get rid of ExclusionState.  Exclusion is now a simple weak_ptr to a Task.
If the weak_ptr is expired, the Exclusion is unlocked.  If the weak_ptr
is not expired, it points to the Task which owns the Exclusion.

try_lock now appends the Task attempting to lock the Exclusion directly
to the owning Task, eliminating the need for Exclusion to have one.
This also removes the need to call insert_task separately, though
insert_task remains for other use cases.

With no ExclusionState there is no need for a string argument to
Exclusion's constructor, so get rid of that too.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:56 -05:00
Zygo Blaxell 7fdb87143c task: get rid of the separate Barrier and BarrierLock
Make one class Barrier which is copiable, so we don't have to
have users making shared Barrier all the time.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:55 -05:00
Zygo Blaxell d345ea2b78 readahead: use emulation
It seems that readahead() does not work on btrfs, or at least it has
no discernable effect.  Enable the workaround instead.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:55 -05:00
Zygo Blaxell a2e1887c52 bees: use MultiLocker to serialize dedupe and logical_ino
In current kernels there is a bug which leads to an infinite loop in
add_all_parents().  The bug is triggered by one thread running dedupe
while another runs logical_ino.

Work around this by ensuring that bees process never runs dedupe and
logical_ino ioctls at the same time.  Any number of either can run
at the same time, but not one of both.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:55 -05:00
Zygo Blaxell 4a4a2de89f multilocker: serialize conflicting parallel operations
For performance or workaround reasons we sometimes have to avoid doing
two conflicting operations at the same time, but we can still run any
number of non-conflicting operations in parallel.

MultiLocker (suggestions for a better class name welcome) blocks the
calling thread until there are no threads attempting to run a conflicting
operation.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:54 -05:00
Zygo Blaxell cc87125e41 bees: drop bees_sync, we will not need it
bees_sync() was an exception-trapping wrapper around fsync() which is
not needed in any of the contexts from which it was called:

	1.  dedupe operations implicitly flush the src data, so there is
	no need to call fsync() to do that twice.

	2.  crawl position is written to a temporary file and renamed
	over the original, which always forces a flush when the original
	exists.  On the first write, where there is no original, a
	crash would result in starting over with an empty or hole-filled
	beescrawl file, which is the initial state of bees.  There is also
	a long history of kernel bugs triggered by fsync() in this case.

	3.  we use unreadahead to trigger writeback for flushing the
	hash table to persistent storage.  Here is a space where we might
	use fsync after all, as part of bees_unreadahead's emulation of
	POSIX_FADV_DONTNEED, but we need to get read-once behavior from
	the scanner before we can use this capability.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:54 -05:00
Zygo Blaxell be9321cdb3 roots: correctly track crawl dirty state
If there's an error while writing the crawl state, the state should
remain dirty.  If the crawl state is successfully written, the state
is only clean if there were no changes to crawl state since the write
was committed.  We need to release the lock while writing the state but
correctly set the dirty flag when the state is written successfully.

Replace the bool with a version number counter.  Track the last version
successfully saved and the current version of the crawl state.  The state
is dirty if these counters disagree and clean if they agree.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:54 -05:00
Zygo Blaxell a9c81e5531 bees: drop m_parent_ctx
It has not been used since 2016.

Also drop the explicit default constructor.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:54 -05:00
Zygo Blaxell 942800ad00 fd: add some doxygen
Still very incomplete, but better than it was before.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:54 -05:00
Zygo Blaxell 21c08008e6 namedptr: add some doxygen, fix the #endif comment
Document the overall purpose of the class and what some of the methods do,
particularly the ones with terrible names like 'insert_item' (which only
inserts an item after calling the Function).

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:54 -05:00
Zygo Blaxell 30ece57116 fs: export btrfs_compress_type_ntoa
We already had a function that was _similar_, so add decoding for compress
type NONE, give it a less specific name, and declare it in fs.h.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:54 -05:00
Zygo Blaxell 6556566f54 ntoa: fix type of mask
It really needs to be uint64_t, but at least it now doesn't contradict
the definition in the earlier header.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:53 -05:00
Zygo Blaxell ece58cc910 cache: add a method to get estimated cache size
Estimated because there is no lock preventing the result from
changing before it is used.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-12-20 20:50:53 -05:00
Zygo Blaxell 331cb142e3 fs: make dedupe work again after a really unfortunate build fix
In commit 14ce81c08 "fs: get rid of silly base class that causes build
failures now" I neglected to set the dest_count field in the ioctl
arg structure, so bees master hasn't been deduping anything for about
three weeks.

I'd put a THROW_CHECK in here to catch this kind of bug in the future,
but it would be placed at exactly the point where this fix is.

Fixes: 14ce81c08
Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-11-05 13:43:21 -04:00
Zygo Blaxell 5953ea6d3c fs: update btrfs compatibility header: add csum types, BTRFS_FS_INFO_FLAG_GENERATION and _METADATA_UUID
I guess this means it's "args_v3" now?

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-10-25 12:56:16 -04:00
Zygo Blaxell 07a4c9e8c0 roots: sprinkle on some more const
Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-10-25 12:56:16 -04:00
Zygo Blaxell 8f6f8e4ac2 roots: make sure we can never get a uint_max transid
If we iterate over all roots to find the max transid, but the set of
all roots is empty, we'll get a nonsense number.  Make sure that number
doesn't reach the crawling logic by killing it with an exception.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-10-25 12:56:16 -04:00
Zygo Blaxell 972721016b fs: get rid of base class fiemap
Yet another build failure of the form:

	error: flexible array member fiemap... not at end of struct crucible::Fiemap...

bees doesn't use fiemap any more, so the fixes here are minimal changes
to make it build, not shining examples of C++ class design.

Signer-off-by: Zygo Blaxell <bees@furryterror.org>
2022-10-25 12:56:16 -04:00
Zygo Blaxell 5040303f50 fs: get rid of base class btrfs_data_container
This fixes another build failure of the form:

	error: flexible array member btrfs_... not at end of struct crucible::Btrfs...

Fixes: https://github.com/Zygo/bees/issues/236
Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-10-23 22:42:57 -04:00
Zygo Blaxell 3654738f56 bees: fix deprecated-copy warnings for clang-14
Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-10-23 22:39:59 -04:00
Zygo Blaxell be3c54e14c extentwalker: drop explicit default constructors
They're all public because it's a struct, so there's no need to make
them explicit.  clang-14 deprecates these.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-10-23 22:39:59 -04:00
Zygo Blaxell 587588d53f bytevector: fix length check
ByteVectors, and shared subranges thereof, might be empty.  The parameter
check should allow that.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-10-10 17:40:33 -04:00
Zygo Blaxell 14ce81c081 fs: get rid of silly base class that causes build failures now
The base class thing was an ugly way to get around the lack of C99
compound literals in C++, and also to make the bare ioctls usable with
the derived classes.

Today, both clang and gcc have C99 compound literals, so there's no need
to do crazy things with memset.  We never used the derived classes for
ioctls, and for this specific ioctl it would have been a very, very bad
idea, so there's no need to support that either.  We do need to jump
through hoops for ostream& operator<<() but we had to do those anyway
as there are other members in the derived type.

So we can simply drop the base class, and build the args object on the
stack in `do_ioctl`.  This also removes the need to verify initialization.

There's no bug here since the `info` member of the base class was
never used in place by the derived class, but new compilers reject the
flexible array member in the base class because the derived class makes
`info` be not at the end of the struct any more:

	error: flexible array member btrfs_ioctl_same_args::info not at end of struct crucible::BtrfsExtentSame

Fixes: https://github.com/Zygo/bees/issues/232
Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-10-09 20:39:15 -04:00
Zygo Blaxell a32cd5247f docs: update kernel bugs list for 5.18 ptvf fix
Also correct my own style for the fixed version column.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-08-17 13:04:06 -04:00
Zygo Blaxell 9c68f15474 README: update copyright year 2022
It has been some years since the copyright statement was updated.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-07-29 22:20:02 -04:00
Zygo Blaxell 5f3cb9b374 docs: update kernel bugs list for 2022-07-29
* RAID1 device count problems fixed
 * log tree replay parent transid verify failure in 5.18 and 5.19 added, patches available but not upstream yet
 * flushoncommit issues fixed, discussion section removed
 * LOGICAL_INO vs dedupe hang added

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2022-07-29 22:07:26 -04:00
Zygo Blaxell fbf6b395c8 types: member m_fd in BeesFileRange must be protected against data races
We had an unfortunate pattern of:

	const BeesFileRange bfr;
	shared_ptr<BeesContext> ctx;
	// ...
	BEESNOTE("foo " << bfr);
	bfr.fd(ctx);
	BEESNOTE("foo after opening: " << bfr);

If dump_status started running after the first BEESNOTE, but before
the second, then bfr.fd() might expose a single Fd object's shared_ptr
member to two threads at the same time (the thread running dump_status
and the thread running BEESNOTE) without protection by a lock.  One of
the threads would see a partially-initialized Fd object, and the other
thread would crash on an assertion failure, e.g.

	#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
	#1  0x00007f4c4fde5537 in __GI_abort () at abort.c:79
	#2  0x00007f4c4fde540f in __assert_fail_base (fmt=0x7f4c4ff4e128 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=0x5557605629dd "!m_destroyed", file=0x5557605627c0 "../include/crucible/namedptr.h", line=77, function=<optimized out>) at assert.c:92
	#3  0x00007f4c4fdf4662 in __GI___assert_fail (assertion=assertion@entry=0x5557605629dd "!m_destroyed", file=file@entry=0x5557605627c0 "../include/crucible/namedptr.h", line=line@entry=77,
	    function=function@entry=0x555760562970 "crucible::NamedPtr<Return, Arguments>::Value::~Value() [with Return = crucible::IOHandle; Arguments = {int}]") at assert.c:101
	#4  0x00005557605306f6 in crucible::NamedPtr<crucible::IOHandle, int>::Value::~Value (this=0x7f4a3c2ff0d0, __in_chrg=<optimized out>) at ../include/crucible/namedptr.h:77
	#5  0x00005557605137da in std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release (this=0x7f4a3c2ff0c0) at /usr/include/c++/10/bits/shared_ptr_base.h:151
	#6  std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release (this=0x7f4a3c2ff0c0) at /usr/include/c++/10/bits/shared_ptr_base.h:151
	#7  std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count (this=0x7f4c4c5b5f28, __in_chrg=<optimized out>) at /usr/include/c++/10/bits/shared_ptr_base.h:733
	#8  std::__shared_ptr<crucible::IOHandle, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr (this=0x7f4c4c5b5f20, __in_chrg=<optimized out>) at /usr/include/c++/10/bits/shared_ptr_base.h:1183
	#9  std::shared_ptr<crucible::IOHandle>::~shared_ptr (this=0x7f4c4c5b5f20, __in_chrg=<optimized out>) at /usr/include/c++/10/bits/shared_ptr.h:121
	#10 crucible::Fd::~Fd (this=0x7f4c4c5b5f20, __in_chrg=<optimized out>) at ../include/crucible/fd.h:46
	#11 BeesFileRange::file_size (this=0x7f4c4e5ba4a0) at bees-types.cc:156
	#12 0x0000555760513950 in operator<< (os=..., bfr=...) at bees-types.cc:80
	#13 0x000055576050d662 in std::function<void (std::ostream&)>::operator()(std::ostream&) const (__args#0=..., this=0x7f4c4e5b9f60) at /usr/include/c++/10/bits/std_function.h:622
	#14 BeesNote::get_status[abi:cxx11]() () at bees-trace.cc:165
	#15 0x00005557604c9676 in BeesContext::dump_status (this=0x5557611c4de0) at bees-context.cc:89
	#16 0x00005557605206fb in std::function<void ()>::operator()() const (this=this@entry=0x7f4c4c5b65f0) at /usr/include/c++/10/bits/std_function.h:622
	#17 crucible::catch_all(std::function<void ()> const&, std::function<void (std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)> const&) (f=..., explainer=...) at error.cc:55
	#18 0x000055576050aaa7 in operator() (__closure=0x5557611c52c8) at bees-thread.cc:22
	#19 0x00007f4c501beed0 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
	#20 0x00007f4c502c8ea7 in start_thread (arg=<optimized out>) at pthread_create.c:477
	#21 0x00007f4c4febddef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Fix by making BeesFileRange::m_fd really const (not just mutable),
then fix all the broken code referencing it.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2021-12-19 15:10:02 -05:00
Zygo Blaxell 26acc6adfd bytevector: introduce BEES_VALGRIND to help work around valgrind
valgrind doesn't understand ioctl arguments, so it does not know if
or when they initialize memory, and it complains about conditionals
depending on data that comes out of ioctls.  That's a problem for bees,
where every decision we ever make is based on data an ioctl gave us.

Fix the initialization issue by using calloc instead of malloc for
ByteVectors when we are building for valgrind.  Don't enable this by
default because all the callocs aren't necessary (assuming the rest
of the code is correct) and hurt performance.

Define BEES_VALGRIND in localconf to activate, e.g.

	echo CCFLAGS += -DBEES_VALGRIND=1 >> localconf

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2021-12-19 15:10:02 -05:00
Zygo Blaxell 01734e6d4b hash: initialize m_dirty in BeesHashTable
It turns out we never set m_dirty's initial value.  This is not a
practical problem because 1) it's mostly harmless if m_dirty is spuriously
true, 2) we set it to true every time bees scans a data block, and 3)
the allocation happens early in startup when most memory allocations
are using zero-filled pages, so it's probably getting a false value at
construction in most cases.

valgrind complains about it, so it has to go.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2021-12-19 15:10:02 -05:00
Zygo Blaxell 84094c7cb9 context: use consistent status for dedupe in log and thread note
Once the physical addresses are known, put them where they can be
seen in BEESTATUS as well as the log.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2021-12-19 15:10:02 -05:00
Zygo Blaxell a3d2bc26d5 progress: lock down some const methods
begin() and end() don't mutate their object

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2021-12-19 15:10:02 -05:00
Zygo Blaxell d0c35b4734 fs: yet another const
References to the search key do not need to be modified.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2021-12-19 15:10:02 -05:00