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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
