When we do a read to a buffer that's mapped into userspace, it's
possible to get a spurious checksum error if userspace was modified the
buffer at the same time.
When we retry those, they have to be bounced before we know definitively
whether we're reading corrupt data.
But the retry path propagates read flags differently, so needs special
handling.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kill the READ_ERR/READ_RETRY/READ_RETRY_AVOID enums, and add standard
error codes that describe precisely which error occured.
This is going to be used for the data move path, to move but poison
extents with checksum errors.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
dm-flakey is busted, and this is simpler anyways - this lets us test the
checksum error retry ptahs
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
These are commonly needed when debugging, and saves from having to ask
users to dig.
Also, rebalance_status now includes pending rebalance work.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We're improving our handling of write errors - we shouldn't write
degraded data just because a write failed once, we should retry it (on
other devices, if possible).
But for this to work, we need to kick devices out when they're only
returning errors - otherwise those retries will loop infinitely.
This adds a configurable timeout - if writes are failing for too long,
we'll set that device read-only.
In the future we should also implement more tracking and another knob
for an "allowed error rate", so that we can kick out drives that are
acting "unhealthy".
Another thing we'll want is a mechanism (likely in userspace) for
bringing a device back in after a transient error - perhaps a cable was
jiggled, or there was a controller reset.
After transient errors we also need a mechanism to walk (from the
journal) recent btree updates that weren't flushed to that device and
treat them as "degraded", since unflushed data may well not have been
written. Out of scope for this patch, but becoming relevant.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Previously, we woudn't try to read at all from a failed device - that
doesn't make much sense, the device may be unhealthy (perhaps taking
longer than it should to service reads), but if it's our only option we
should still try to read from it.
Now, bch2_bkey_pick_read_device() will pick failed devices only if there
are no non-failed replicas to read from.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The next patch implementing freezing will change bch2_dev_get_ioref() to
sleep if a device is currently frozen.
Add an annotation and fix the journal code accordingly.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This was completely fubar; it's now simplified a bit as well.
Note that for_each_online_member() takes and releases io_refs as it
iterates, so we need to release that if we break.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We can't use the standard fs_holder_ops because they're meant for single
device filesystems - fs_bdev_mark_dead() in particular - and they assume
that the blk_holder is the super_block, which also doesn't work for a
multi device filesystem.
These generally follow the standard fs_holder_ops; the
locking/refcounting is a bit simplified because c->ro_ref suffices, and
bch2_fs_bdev_mark_dead() is not necessarily shutting down the entire
filesystem.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This is necessary for the new blk_holder_ops, which want the vfs
super_block available for synchronization.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Note that we open block devices before we allocate bch_fs, but once
attached to a filesystem they will be closed before the bch_fs is torn
down - so stashing a pointer without a refcount looks incorrect but it's
not.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We need to start accounting successes for every IO, not just failures,
so introduce a unified hook for io completion accounting and convert
io_read.c.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We were using our device pointer after we'd released our ref to it.
Unlikely to be a race that's practical to hit, since actually removing a
member device is a whole process besides just taking it offline, but -
needs to be fixed.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
If a device is ro or failed, we might not have anywhere to move a
replica.
Check for this early, before doing the read and attempting to write.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This implements a new extent field bitflags that apply to the whole
extent. There's been a couple things we've wanted this for in the past,
but the immediate need is extent poisoning, to solve a rebalance issue.
Unknown extent fields can't be parsed (we won't known their size, so we
can't advance to the next field), so this is an incompat feature, and
using it prevents the filesystem from being mounted by old versions.
This also adds the BCH_EXTENT_poisoned flag; this indicates that the
data is known to be bad (i.e. there was a checksum error, and we had to
write a new checksum) and reads will return errors.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Use error type alloc_v3_unpack_error in bch2_alloc_v3_validate().
Fixes: b65db750e2 ("bcachefs: Enumerate fsck errors")
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Footnotes list are outputted in htmldocs simply as long-running
paragraph instead. Use reST numbered footnotes syntax for the job.
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
SubmttingPatches.rst has 4 section headings, all under the same heading
levels. In absence of title headings, these section headings are all
ended up as title headings in the docs output, which also affect
the index toctree (increasing titles to 6 from the original 2)
due to :numbered: option.
Demote second-to-last section headings, making "Submitting patches
to bcachefs" as title heading.
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bcachefs subsystem currently has 4 docs: two are development notes and
the rest are actual filesystem docs. These two groups are clearly
distinct and can be organized.
Split the toctree into two, one for each docs group. While at it, also
reduce :maxdepth: so that only title headings are listed in the
toctrees.
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The doc lists dirent structure for both regular and casefolded names,
yet it is written (and rendered) as long paragraph instead.
Write the structure list as bullet list.
Fixes: bc5cc09246c5 ("bcachefs: bcachefs_metadata_version_casefolding")
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Sphinx reports htmldocs warnings on dentry/dcache section:
Documentation/filesystems/bcachefs/casefolding.rst:75: WARNING: Title underline too short.
dentry/dcache considerations
--------- [docutils]
Documentation/filesystems/bcachefs/casefolding.rst:84: WARNING: Definition list ends without a blank line; unexpected unindent. [docutils]
Fix the section by:
* Extending the section underline to match the section title length;
* Separating problem list from surrounding paragraphs.
Fixes: bc5cc09246c5 ("bcachefs: bcachefs_metadata_version_casefolding")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/linux-next/20250221161911.2d16138b@canb.auug.org.au/
Closes: https://lore.kernel.org/linux-next/20250221162135.79be0147@canb.auug.org.au/
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Sphinx reports htmldocs warning:
Documentation/filesystems/bcachefs/casefolding.rst:36: WARNING: Inline interpreted text or phrase reference start-string without end-string. [docutils]
That's because NUL word is italicized but it is written in plural form
instead (`NUL`s). Sphinx, however, doesn't tip over when the italicized
word in this fashion is followed by punctuation instead.
Do not italicize the word to keep Sphinx happy.
Fixes: bc5cc09246c5 ("bcachefs: bcachefs_metadata_version_casefolding")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/linux-next/20250221162135.79be0147@canb.auug.org.au/
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This patch implements support for case-insensitive file name lookups
in bcachefs.
The implementation uses the same UTF-8 lowering and normalization that
ext4 and f2fs is using.
More information is provided in Documentation/bcachefs/casefolding.rst
Compatibility notes:
This uses the new versioning scheme for incompatible features where an
incompatible feature is tied to a version number: the superblock says
"we may use incompat features up to x" and "incompat features up to x
are in use", disallowing mounting by previous versions.
Additionally, and old style incompat feature bit is used, so that
kernels without utf8 casefolding support know if casefolding
specifically is in use and they're allowed to mount.
Signed-off-by: Joshua Ashton <joshua@froggi.es>
Cc: André Almeida <andrealmeid@igalia.com>
Cc: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Splits out the code that allocates the dirent and initializes the name
to make things easier to implement casefolding in a future commit.
Cc: André Almeida <andrealmeid@igalia.com>
Cc: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Joshua Ashton <joshua@froggi.es>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a persistent LRU for stripes, ordered by "number of empty blocks",
i.e. order in which we wish to reuse them.
This will replace the in-memory stripes heap, so we can kill off reading
stripes into memory at startup.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Stripes now have backpointers.
This is needed for proper scrub - stripe checksums need to be verified,
separately from extents within the stripe, since a block may not be full
of live extents but it's still needed for reconstruct.
And this will be needed for (efficient) evacuate/repair paths.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Now that we've got cached backpointers and aren't leaving around stale
pointers on bucket invalidation, we no longer need the periodic (rare)
gc_gens - which recalculates each bucket's oldest gen to avoid wraparound.
We can't delete that code because we've got to support existing
filesystems that will still have stale pointers, but this gets rid of
another scalability limit.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Cached pointers now have backpointers.
This means that we'll be able to kill cached pointers in the
bucket_invalidate path, when invalidating/reusing buckets containing
cached data, instead of leaving them around to be cleaned up by gc_gens
garbago collection - which requires a full metadata scan.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
