Pull bcachefs updates from Kent Overstreet:
"On disk format is now soft frozen: no more required/automatic are
anticipated before taking off the experimental label.
Major changes/features since 6.14:
- Scrub
- Blocksize greater than page size support
- A number of "rebalance spinning and doing no work" issues have been
fixed; we now check if the write allocation will succeed in
bch2_data_update_init(), before kicking off the read.
There's still more work to do in this area. Later we may want to
add another bitset btree, like rebalance_work, to track "extents
that rebalance was requested to move but couldn't", e.g. due to
destination target having insufficient online devices.
- We can now support scaling well into the petabyte range: latest
bcachefs-tools will pick an appropriate bucket size at format time
to ensure fsck can run in available memory (e.g. a server with
256GB of ram and 100PB of storage would want 16MB buckets).
On disk format changes:
- 1.21: cached backpointers (scalability improvement)
Cached replicas now get backpointers, which means we no longer rely
on incrementing bucket generation numbers to invalidate cached
data: this lets us get rid of the bucket generation number garbage
collection, which had to periodically rescan all extents to
recompute bucket oldest_gen.
Bucket generation numbers are now only used as a consistency check,
but they're quite useful for that.
- 1.22: stripe backpointers
Stripes now have backpointers: erasure coded stripes have their own
checksums, separate from the checksums for the extents they contain
(and stripe checksums also cover the parity blocks). This is
required for implementing scrub for stripes.
- 1.23: stripe lru (scalability improvement)
Persistent lru for stripes, ordered by "number of empty blocks".
This is used by the stripe creation path, which depending on free
space may create a new stripe out of a partially empty existing
stripe instead of starting a brand new stripe.
This replaces an in-memory heap, and means we no longer have to
read in the stripes btree at startup.
- 1.24: casefolding
Case insensitive directory support, courtesy of Valve.
This is an incompatible feature, to enable mount with
-o version_upgrade=incompatible
- 1.25: extent_flags
Another incompatible feature requiring explicit opt-in to enable.
This adds a flags entry to extents, and a flag bit that marks
extents as poisoned.
A poisoned extent is an extent that was unreadable due to checksum
errors. We can't move such extents without giving them a new
checksum, and we may have to move them (for e.g. copygc or device
evacuate). We also don't want to delete them: in the future we'll
have an API that lets userspace ignore checksum errors and attempt
to deal with simple bitrot itself. Marking them as poisoned lets us
continue to return the correct error to userspace on normal read
calls.
Other changes/features:
- BCH_IOCTL_QUERY_COUNTERS: this is used by the new 'bcachefs fs top'
command, which shows a live view of all internal filesystem
counters.
- Improved journal pipelining: we can now have 16 journal writes in
flight concurrently, up from 4. We're logging significantly more to
the journal than we used to with all the recent disk accounting
changes and additions, so some users should see a performance
increase on some workloads.
- BCH_MEMBER_STATE_failed: previously, we would do no IO at all to
devices marked as failed. Now we will attempt to read from them,
but only if we have no better options.
- New option, write_error_timeout: devices will be kicked out of the
filesystem if all writes have been failing for x number of seconds.
We now also kick devices out when notified by blk_holder_ops that
they've gone offline.
- Device option handling improvements: the discard option should now
be working as expected (additionally, in -tools, all device options
that can be set at format time can now be set at device add time,
i.e. data_allowed, state).
- We now try harder to read data after a checksum error: we'll do
additional retries if necessary to a device after after it gave us
data with a checksum error.
- More self healing work: the full inode <-> dirent consistency
checks that are currently run by fsck are now also run every time
we do a lookup, meaning we'll be able to correct errors at runtime.
Runtime self healing will be flipped on after the new changes have
seen more testing, currently they're just checking for consistency.
- KMSAN fixes: our KMSAN builds should be nearly clean now, which
will put a massive dent in the syzbot dashboard"
* tag 'bcachefs-2025-03-24' of git://evilpiepirate.org/bcachefs: (180 commits)
bcachefs: Kill unnecessary bch2_dev_usage_read()
bcachefs: btree node write errors now print btree node
bcachefs: Fix race in print_chain()
bcachefs: btree_trans_restart_foreign_task()
bcachefs: bch2_disk_accounting_mod2()
bcachefs: zero init journal bios
bcachefs: Eliminate padding in move_bucket_key
bcachefs: Fix a KMSAN splat in btree_update_nodes_written()
bcachefs: kmsan asserts
bcachefs: Fix kmsan warnings in bch2_extent_crc_pack()
bcachefs: Disable asm memcpys when kmsan enabled
bcachefs: Handle backpointers with unknown data types
bcachefs: Count BCH_DATA_parity backpointers correctly
bcachefs: Run bch2_check_dirent_target() at lookup time
bcachefs: Refactor bch2_check_dirent_target()
bcachefs: Move bch2_check_dirent_target() to namei.c
bcachefs: fs-common.c -> namei.c
bcachefs: EIO cleanup
bcachefs: bch2_write_prep_encoded_data() now returns errcode
bcachefs: Simplify bch2_write_op_error()
...