Commit graph

592 commits

Author SHA1 Message Date
Rik van Riel
23fd95663b btrfs: allocate eb-attached btree pages as movable
Extent buffer pages allocated by alloc_extent_buffer() are attached to
btree_inode->i_mapping (the buffer_tree path), reach the LRU, and are
served by the btree_migrate_folio aops in fs/btrfs/disk-io.c. They are
migratable in practice once their owning extent buffer hits refs == 1,
which happens naturally. The buddy allocator classifies them by GFP,
however, and bare GFP_NOFS lands them in MIGRATE_UNMOVABLE pageblocks.

The result: every btree_inode page we read in pins an unmovable pageblock
from the page-superblock allocator's perspective, even though the page
itself can be moved.

Have each caller of btrfs_alloc_page_array, btrfs_alloc_folio_array,
and alloc_eb_folio_array pass in the full GFP mask directly, instead
of having the functions calculate it from boolean flags.

The alloc_extent_buffer call site passes GFP_NOFS | __GFP_NOFAIL |
__GFP_MOVABLE. All other call sites pass plain GFP_NOFS.

Three categories of caller stay on bare GFP_NOFS, deliberately:

  - alloc_dummy_extent_buffer / btrfs_clone_extent_buffer: the
    resulting eb is EXTENT_BUFFER_UNMAPPED, folio->mapping stays NULL,
    the folios never enter LRU, never get migrate_folio aops. Tagging
    them __GFP_MOVABLE would violate the page allocator's migrability
    contract and they would defeat compaction in MOVABLE pageblocks
    where isolate_migratepages_block skips non-LRU non-movable_ops
    pages outright.

  - btrfs_alloc_page_array callers in fs/btrfs/raid56.c (stripe
    pages), fs/btrfs/inode.c (encoded reads), fs/btrfs/ioctl.c (io_uring
    encoded reads), fs/btrfs/relocation.c (relocation buffers): same
    contract violation. raid56 stripe_pages additionally persist in
    the stripe cache (RBIO_CACHE_SIZE=1024) well beyond a single I/O,
    so they are not transient enough to hand-wave the contract.

  - btrfs_alloc_folio_array caller in fs/btrfs/scrub.c (stripe
    folios): same -- stripe->folios[] are private buffers freed via
    folio_put in release_scrub_stripe.

This change targets the dominant fragmentation source observed on the
page-superblock series: ~28 GB of btree_inode pages parked across
many tainted superpageblocks on a 250 GB test system with btrfs root,
preventing 1 GiB hugepage allocation from those regions. With the
movable hint, those pages now land in MOVABLE pageblocks where the
existing background defragger drains them through the standard
PB_has_movable gate, no LRU-sample fallback needed.

Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-06-09 18:22:45 +02:00
Filipe Manana
7801f3ea95 btrfs: tag as unlikely if statements that check for fs in error state
Having the filesystem in an error state, meaning we had a transaction
abort, is unexpected. Mark every check for the error state with the
unlikely annotation to convey that and to allow the compiler to generate
better code.

On x86_64, using gcc 14.2.0-19 from Debian, resulted in a slightly
reduced object size and better code.

Before:

  $ size fs/btrfs/btrfs.ko
     text	   data	    bss	    dec	    hex	filename
  2008598	 175912	  15592	2200102	 219226	fs/btrfs/btrfs.ko

After:

  $ size fs/btrfs/btrfs.ko
     text	   data	    bss	    dec	    hex	filename
  2008450	 175912	  15592	2199954	 219192	fs/btrfs/btrfs.ko

Reviewed-by: Anand Jain <asj@kernel.org>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-07 19:41:42 +02:00
Qu Wenruo
c4bc2dd32c btrfs: introduce a common helper to calculate the size of a bio
We have several call sites doing the same work to calculate the size of
a bio:

	struct bio_vec *bvec;
	u32 bio_size = 0;
	int i;

	bio_for_each_bvec_all(bvec, bio, i)
		bio_size += bvec->bv_len;

We can use a common helper instead of open-coding it everywhere.

This also allows us to constify the @bio_size variables used in all the
call sites.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-07 18:55:59 +02:00
Linus Torvalds
c44db6c820 for-7.0-rc2-tag
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Merge tag 'for-7.0-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "One-liner or short fixes for minor/moderate problems reported recently:

   - fixes or level adjustments of error messages

   - fix leaked transaction handles after aborted transactions, when
     using the remap tree feature

   - fix a few leaked chunk maps after errors

   - fix leaked page array in io_uring encoded read if an error occurs
     and the 'finished' is not called

   - fix double release of reserved extents when doing a range COW

   - don't commit super block when the filesystem is in shutdown state

   - fix squota accounting condition when checking members vs parent
     usage

   - other error handling fixes"

* tag 'for-7.0-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: check block group lookup in remove_range_from_remap_tree()
  btrfs: fix transaction handle leaks in btrfs_last_identity_remap_gone()
  btrfs: fix chunk map leak in btrfs_map_block() after btrfs_translate_remap()
  btrfs: fix chunk map leak in btrfs_map_block() after btrfs_chunk_map_num_copies()
  btrfs: fix compat mask in error messages in btrfs_check_features()
  btrfs: print correct subvol num if active swapfile prevents deletion
  btrfs: fix warning in scrub_verify_one_metadata()
  btrfs: fix objectid value in error message in check_extent_data_ref()
  btrfs: fix incorrect key offset in error message in check_dev_extent_item()
  btrfs: fix error message order of parameters in btrfs_delete_delayed_dir_index()
  btrfs: don't commit the super block when unmounting a shutdown filesystem
  btrfs: free pages on error in btrfs_uring_read_extent()
  btrfs: fix referenced/exclusive check in squota_check_parent_usage()
  btrfs: remove pointless WARN_ON() in cache_save_setup()
  btrfs: convert log messages to error level in btrfs_replay_log()
  btrfs: remove btrfs_handle_fs_error() after failure to recover log trees
  btrfs: remove redundant warning message in btrfs_check_uuid_tree()
  btrfs: change warning messages to error level in open_ctree()
  btrfs: fix a double release on reserved extents in cow_one_range()
  btrfs: handle discard errors in in btrfs_finish_extent_commit()
2026-03-03 09:08:00 -08:00
Mark Harmstone
44e2fda664 btrfs: fix warning in scrub_verify_one_metadata()
Commit b471965fdb ("btrfs: fix replace/scrub failure with
metadata_uuid") fixed the comparison in scrub_verify_one_metadata() to
use metadata_uuid rather than fsid, but left the warning as it was. Fix
it so it matches what we're doing.

Fixes: b471965fdb ("btrfs: fix replace/scrub failure with metadata_uuid")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-26 15:03:28 +01:00
Kees Cook
189f164e57 Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses
Conversion performed via this Coccinelle script:

  // SPDX-License-Identifier: GPL-2.0-only
  // Options: --include-headers-for-types --all-includes --include-headers --keep-comments
  virtual patch

  @gfp depends on patch && !(file in "tools") && !(file in "samples")@
  identifier ALLOC = {kmalloc_obj,kmalloc_objs,kmalloc_flex,
 		    kzalloc_obj,kzalloc_objs,kzalloc_flex,
		    kvmalloc_obj,kvmalloc_objs,kvmalloc_flex,
		    kvzalloc_obj,kvzalloc_objs,kvzalloc_flex};
  @@

  	ALLOC(...
  -		, GFP_KERNEL
  	)

  $ make coccicheck MODE=patch COCCI=gfp.cocci

Build and boot tested x86_64 with Fedora 42's GCC and Clang:

Linux version 6.19.0+ (user@host) (gcc (GCC) 15.2.1 20260123 (Red Hat 15.2.1-7), GNU ld version 2.44-12.fc42) #1 SMP PREEMPT_DYNAMIC 1970-01-01
Linux version 6.19.0+ (user@host) (clang version 20.1.8 (Fedora 20.1.8-4.fc42), LLD 20.1.8) #1 SMP PREEMPT_DYNAMIC 1970-01-01

Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-22 08:26:33 -08:00
Linus Torvalds
bf4afc53b7 Convert 'alloc_obj' family to use the new default GFP_KERNEL argument
This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 17:09:51 -08:00
Kees Cook
69050f8d6d treewide: Replace kmalloc with kmalloc_obj for non-scalar types
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-21 01:02:28 -08:00
Filipe Manana
6329592ca6 btrfs: remove out label in scrub_find_fill_first_stripe()
There is no point in having the label since all it does is return the
value in the 'ret' variable. Instead make every goto return directly
and remove the label.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03 07:56:22 +01:00
Filipe Manana
4ac81c3811 btrfs: use the btrfs_block_group_end() helper everywhere
We have a helper to calculate a block group's exclusive end offset, but
we only use it in some places. Update every site that open codes the
calculation to use the helper.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03 07:54:36 +01:00
Qu Wenruo
fab0c0f03c btrfs: introduce BTRFS_PATH_AUTO_RELEASE() helper
There are already several bugs with on-stack btrfs_path involved, even
it is already a little safer than btrfs_path pointers (only leaks the
extent buffers, not the btrfs_path structure itself)

- Patch "btrfs: make sure extent and csum paths are always released in
  scrub_raid56_parity_stripe()"

- Patch "btrfs: fix a potential path leak in print_data_reloc_error()"

Thus there is a real need to apply auto release for those on-stack paths.

Introduces a new macro, BTRFS_PATH_AUTO_RELEASE() which defines one
on-stack btrfs_path structure, initialize it all to 0, then call
btrfs_release_path() on it when exiting the scope.

This applies to current 3 on-stack path usages:

- defrag_get_extent() in defrag.c

- print_data_reloc_error() in inode.c
  There is a special case where we want to release the path early before
  the time consuming iterate_extent_inodes() call, thus that manual
  early release is kept as is, with an extra comment added.

- scrub_radi56_parity_stripe() in scrub.c

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03 06:38:32 +01:00
Eric Biggers
fe11ac191c btrfs: switch to library APIs for checksums
Make btrfs use the library APIs instead of crypto_shash, for all
checksum computations.  This has many benefits:

- Allows future checksum types, e.g. XXH3 or CRC64, to be more easily
  supported.  Only a library API will be needed, not crypto_shash too.

- Eliminates the overhead of the generic crypto layer, including an
  indirect call for every function call and other API overhead.  A
  microbenchmark of btrfs_check_read_bio() with crc32c checksums shows a
  speedup from 658 cycles to 608 cycles per 4096-byte block.

- Decreases the stack usage of btrfs by reducing the size of checksum
  contexts from 384 bytes to 240 bytes, and by eliminating the need for
  some functions to declare a checksum context at all.

- Increases reliability.  The library functions always succeed and
  return void.  In contrast, crypto_shash can fail and return errors.
  Also, the library functions are guaranteed to be available when btrfs
  is loaded; there's no longer any need to use module softdeps to try to
  work around the crypto modules sometimes not being loaded.

- Fixes a bug where blake2b checksums didn't work on kernels booted with
  fips=1.  Since btrfs checksums are for integrity only, it's fine for
  them to use non-FIPS-approved algorithms.

Note that with having to handle 4 algorithms instead of just 1-2, this
commit does result in a slightly positive diffstat.  That being said,
this wouldn't have been the case if btrfs had actually checked for
errors from crypto_shash, which technically it should have been doing.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03 06:38:32 +01:00
Qu Wenruo
54df8b80cc btrfs: scrub: always update btrfs_scrub_progress::last_physical
[BUG]
When a scrub failed immediately without any byte scrubbed, the returned
btrfs_scrub_progress::last_physical will always be 0, even if there is a
non-zero @start passed into btrfs_scrub_dev() for resume cases.

This will reset the progress and make later scrub resume start from the
beginning.

[CAUSE]
The function btrfs_scrub_dev() accepts a @progress parameter to copy its
updated progress to the caller, there are cases where we either don't
touch progress::last_physical at all or copy 0 into last_physical:

- last_physical not updated at all
  If some error happened before scrubbing any super block or chunk, we
  will not copy the progress, leaving the @last_physical untouched.

  E.g. failed to allocate @sctx, scrubbing a missing device or even
  there is already a running scrub and so on.

  All those cases won't touch @progress at all, resulting the
  last_physical untouched and will be left as 0 for most cases.

- Error out before scrubbing any bytes
  In those case we allocated @sctx, and sctx->stat.last_physical is all
  zero (initialized by kvzalloc()).
  Unfortunately some critical errors happened during
  scrub_enumerate_chunks() or scrub_supers() before any stripe is really
  scrubbed.

  In that case although we will copy sctx->stat back to @progress, since
  no byte is really scrubbed, last_physical will be overwritten to 0.

[FIX]
Make sure the parameter @progress always has its @last_physical member
updated to @start parameter inside btrfs_scrub_dev().

At the very beginning of the function, set @progress->last_physical to
@start, so that even if we error out without doing progress copying,
last_physical is still at @start.

Then after we got @sctx allocated, set sctx->stat.last_physical to
@start, this will make sure even if we didn't get any byte scrubbed, at
the progress copying stage the @last_physical is not left as zero.

This should resolve the resume progress reset problem.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24 22:42:26 +01:00
Filipe Manana
d7fe41044b btrfs: use bool type for btrfs_path members used as booleans
Many fields of struct btrfs_path are used as booleans but their type is
an unsigned int (of one 1 bit width to save space). Change the type to
bool keeping the :1 suffix so that they combine with the previous u8
fields in order to save space. This makes the code more clear by using
explicit true/false and more in line with the preferred style, preserving
the size of the structure.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24 22:42:25 +01:00
David Sterba
1c094e6cce btrfs: make a few more ASSERTs verbose
We have support for optional string to be printed in ASSERT() (added in
19468a623a ("btrfs: enhance ASSERT() to take optional format
string")), it's not yet everywhere it could be so add a few more files.

Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24 22:42:24 +01:00
David Sterba
4decf577fb btrfs: move and rename CSUM_FMT definition
Move the CSUM_FMT* definitions to fs.h where is be the BTRFS_KEY_FMT
and add the prefix for consistency.

Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24 22:42:23 +01:00
Qu Wenruo
07166122b5 btrfs: scrub: factor out parity scrub code into a helper
The function scrub_raid56_parity_stripe() is handling the parity stripe
by the following steps:

- Scrub each data stripes
  And make sure everything is fine in each data stripe

- Cache the data stripe into the raid bio

- Use the cached raid bio to scrub the target parity stripe

Extract the last two steps into a new helper,
scrub_raid56_cached_parity(), as a cleanup and make the error handling
more straightforward.

With the following minor cleanups:

- Use on-stack bio structure
  The bio is always empty thus we do not need any bio vector nor the
  block device. Thus there is no need to allocate a bio, the on-stack
  one is more than enough to cut it.

- Remove the unnecessary btrfs_put_bioc() call if btrfs_map_block()
  failed
  If btrfs_map_block() is failed, @bioc_ret will not be touched thus
  there is no need to call btrfs_put_bioc() in this case.

- Use a proper out: tag to do the cleanup
  Now the error cleanup is much shorter and simpler, just
  btrfs_bio_counter_dec() and bio_uninit().

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24 22:42:22 +01:00
Qu Wenruo
d435c51365 btrfs: make sure extent and csum paths are always released in scrub_raid56_parity_stripe()
Unlike queue_scrub_stripe() which uses the global sctx->extent_path and
sctx->csum_path which are always released at the end of scrub_stripe(),
scrub_raid56_parity_stripe() uses local extent_path and csum_path, as
that function is going to handle the full stripe, whose bytenr may be
smaller than the bytenr in the global sctx paths.

However the cleanup of local extent/csum paths is only happening after
we have successfully submitted an rbio.

There are several error routes that we didn't release those two paths:

- scrub_find_fill_first_stripe() errored out at csum tree search
  In that case extent_path is still valid, and that function itself will
  not release the extent_path passed in.
  And the function returns directly without releasing both paths.

- The full stripe is empty
- Some blocks failed to be recovered
- btrfs_map_block() failed
- raid56_parity_alloc_scrub_rbio() failed
  The function returns directly without releasing both paths.

Fix it by covering btrfs_release_path() calls inside the out: tag.

This is just a hot fix, in the long run we will go scoped based auto
freeing for both local paths.

Fixes: 1dc4888e72 ("btrfs: scrub: avoid unnecessary extent tree search preparing stripes")
Fixes: 3c771c1944 ("btrfs: scrub: avoid unnecessary csum tree search preparing stripes")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24 22:42:22 +01:00
Qu Wenruo
81cea6cd70 btrfs: remove btrfs_bio::fs_info by extracting it from btrfs_bio::inode
Currently there is only one caller which doesn't populate
btrfs_bio::inode, and that's scrub.

The idea is scrub doesn't want any automatic csum verification nor
read-repair, as everything will be handled by scrub itself.

However that behavior is really no different than metadata inode, thus
we can reuse btree_inode as btrfs_bio::inode for scrub.

The only exception is in btrfs_submit_chunk() where if a bbio is from
scrub or data reloc inode, we set rst_search_commit_root to true.
This means we still need a way to distinguish scrub from metadata, but
that can be done by a new flag inside btrfs_bio.

Now btrfs_bio::inode is a mandatory parameter, we can extract fs_info
from that inode thus can remove btrfs_bio::fs_info to save 8 bytes from
btrfs_bio structure.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24 22:40:16 +01:00
Miquel Sabaté Solà
285c3ab28e btrfs: declare free_ipath() via DEFINE_FREE()
The free_ipath() function was being used as a cleanup function
everywhere. Declare it via DEFINE_FREE() so we can use this function
with the __free() helper.

The name has also been adjusted so it's closer to the type's name.

Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24 22:34:51 +01:00
Qu Wenruo
937f99c736 btrfs: scrub: cancel the run if there is a pending signal
Unlike relocation, scrub never checks pending signals, and even for
relocation is only explicitly checking for fatal signal (SIGKILL), not
for regular ones.

Thankfully relocation can still be interrupted by regular signals by
the usage of wait_on_bit(), which is called with TASK_INTERRUPTIBLE.

Do the same for scrub/dev-replace, so that regular signals can also
cancel the scrub/replace run, and more importantly handle v2 cgroup
freezing which is based on signal handling code inside the kernel, and
freezing() function will not return true for v2 cgroup freezing.

This will address the problem that systemd slice freezing will timeout
on long running scrub/dev-replace.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24 22:34:32 +01:00
Qu Wenruo
c7b478504b btrfs: scrub: cancel the run if the process or fs is being frozen
It's a known bug that btrfs scrub/dev-replace can prevent the system
from suspending.

There are at least two factors involved:

- Holding super_block::s_writers for the whole scrub/dev-replace duration
  We hold that percpu rw semaphore through mnt_want_write_file() for the
  whole scrub/dev-replace duration.

  That will prevent the fs being frozen, which can be initiated by
  either the user (e.g. fsfreeze) or power management suspend/hibernate.

- Stuck in the kernel space for a long time
  During suspend all user processes (and some kernel threads) will
  be frozen.
  But if a user space progress has fallen into kernel (scrub ioctl) and
  do not return for a long time, it will make process freezing time out.

  Unfortunately scrub/dev-replace is a long running ioctl, and it will
  prevent the btrfs process from returning to the user space, thus make PM
  suspend/hibernate time out.

Address them in one go:

- Introduce a new helper should_cancel_scrub()
  Which includes the existing cancel request and new fs/process freezing
  checks.

  Here we have to check both fs and process freezing for PM
  suspend/hibernate.

  PM can be configured to freeze filesystems before processes.
  (The current default is not to freeze filesystems, but planned to
  freeze the filesystems as the new default.)

  Checking only fs freezing will fail PM without fs freezing, as the
  process freezing will time out.

  Checking only process freezing will fail PM with fs freezing since the
  fs freezing happens before process freezing.

  And the return value will indicate the reason, -ECANCLED for the
  explicitly canceled runs, and -EINTR for fs freeze or PM reasons.

- Cancel the run if should_cancel_scrub() is true
  Unfortunately canceling is the only feasible solution here, pausing is
  not possible as we will still stay in the kernel space thus will still
  prevent the process from being frozen.

This will cause a user impacting behavior change:

  Dev-replace can be interrupted by PM, and there is no way to resume
  but start from the beginning again.

This means dev-replace may fail on newer kernels, and end users will
need extra steps like using systemd-inhibit to prevent
suspend/hibernate, to get back the old uninterrupted behavior.

This behavior change will need extra documentation updates and
communication with projects involving scrub/dev-replace including
btrfs-progs.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Link: https://lore.kernel.org/linux-btrfs/d93b2a2d-6ad9-4c49-809f-11d769a6f30a@app.fastmail.com/
Reported-by: Chris Murphy <lists@colorremedies.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24 22:24:52 +01:00
Qu Wenruo
02a7e90797 btrfs: scrub: add cancel/pause/removed bg checks for raid56 parity stripes
For raid56, data and parity stripes are handled differently.

For data stripes they are handled just like regular RAID1/RAID10 stripes,
going through the regular scrub_simple_mirror().

But for parity stripes we have to read out all involved data stripes and
do any needed verification and repair, then scrub the parity stripe.

This process will take a much longer time than a regular stripe, but
unlike scrub_simple_mirror(), we do not check if we should cancel/pause
or the block group is already removed.

Aligned the behavior of scrub_raid56_parity_stripe() to
scrub_simple_mirror(), by adding:

- Cancel check
- Pause check
- Removed block group check

Since those checks are the same from the scrub_simple_mirror(), also
update the comments of scrub_simple_mirror() by:

- Remove too obvious comments
  We do not need extra comments on what we're checking, it's really too
  obvious.

- Remove a stale comment about pausing
  Now the scrub is always queuing all involved stripes, and submit them
  in one go, there is no more submission part during pausing.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24 22:21:38 +01:00
David Sterba
aebe2bb0b8 btrfs: fix trivial -Wshadow warnings
When compiling with -Wshadow (also in 'make W=2' build) there are
several reports of shadowed variables that seem to be harmless:

- btrfs_do_encoded_write() - we can reuse 'ordered', there's no previous
			     value that would need to be preserved

- scrub_write_endio() - we need a standalone 'i' for bio iteration

- scrub_stripe() - duplicate ret2 for errors that must not overwrite 'ret'

- btrfs_subpage_set_writeback() - 'flags' is used for another irqsave lock
                                  but is not overwritten when reused for xarray
				  due to scoping, but for clarity let's rename it

- process_dir_items_leaf() - duplicate 'ret', used only for immediate checks

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24 21:37:36 +01:00
Zilin Guan
5fea61aa1c btrfs: scrub: put bio after errors in scrub_raid56_parity_stripe()
scrub_raid56_parity_stripe() allocates a bio with bio_alloc(), but
fails to release it on some error paths, leading to a potential
memory leak.

Add the missing bio_put() calls to properly drop the bio reference
in those error cases.

Fixes: 1009254bf2 ("btrfs: scrub: use scrub_stripe to implement RAID56 P/Q scrub")
CC: stable@vger.kernel.org # 6.6+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-05 20:01:12 +01:00
Qu Wenruo
42d3a055d9 btrfs: do not use folio_test_partial_kmap() in ASSERT()s
[BUG]
Syzbot reported an ASSERT() triggered inside scrub:

  BTRFS info (device loop0): scrub: started on devid 1
  assertion failed: !folio_test_partial_kmap(folio) :: 0, in fs/btrfs/scrub.c:697
  ------------[ cut here ]------------
  kernel BUG at fs/btrfs/scrub.c:697!
  Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
  CPU: 0 UID: 0 PID: 6077 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
  RIP: 0010:scrub_stripe_get_kaddr+0x1bb/0x1c0 fs/btrfs/scrub.c:697
  Call Trace:
   <TASK>
   scrub_bio_add_sector fs/btrfs/scrub.c:932 [inline]
   scrub_submit_initial_read+0xf21/0x1120 fs/btrfs/scrub.c:1897
   submit_initial_group_read+0x423/0x5b0 fs/btrfs/scrub.c:1952
   flush_scrub_stripes+0x18f/0x1150 fs/btrfs/scrub.c:1973
   scrub_stripe+0xbea/0x2a30 fs/btrfs/scrub.c:2516
   scrub_chunk+0x2a3/0x430 fs/btrfs/scrub.c:2575
   scrub_enumerate_chunks+0xa70/0x1350 fs/btrfs/scrub.c:2839
   btrfs_scrub_dev+0x6e7/0x10e0 fs/btrfs/scrub.c:3153
   btrfs_ioctl_scrub+0x249/0x4b0 fs/btrfs/ioctl.c:3163
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:597 [inline]
   __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
   </TASK>
  ---[ end trace 0000000000000000 ]---

Which doesn't make much sense, as all the folios we allocated for scrub
should not be highmem.

[CAUSE]
Thankfully syzbot has a detailed kernel config file, showing that
CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP is set to y.

And that debug option will force all folio_test_partial_kmap() to return
true, to improve coverage on highmem tests.

But in our case we really just want to make sure the folios we allocated
are not highmem (and they are indeed not). Such incorrect result from
folio_test_partial_kmap() is just screwing up everything.

[FIX]
Replace folio_test_partial_kmap() to folio_test_highmem() so that we
won't bother those highmem specific debuging options.

Fixes: 5fbaae4b85 ("btrfs: prepare scrub to support bs > ps cases")
Reported-by: syzbot+bde59221318c592e6346@syzkaller.appspotmail.com
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-10-13 22:31:36 +02:00
David Sterba
cc53bd2085 btrfs: add unlikely annotations to branches leading to EIO
The unlikely() annotation is a static prediction hint that compiler may
use to reorder code out of hot path. We use it elsewhere (namely
tree-checker.c) for error branches that almost never happen, where
EIO is one of them.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-23 08:49:26 +02:00
David Sterba
9264d004a6 btrfs: add unlikely annotations to branches leading to EUCLEAN
The unlikely() annotation is a static prediction hint that compiler may
use to reorder code out of hot path. We use it elsewhere (namely
tree-checker.c) for error branches that almost never happen, where
EUCLEAN (a corruption) is one of them.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-23 08:49:26 +02:00
Sun YangKai
4ca6f24a52 btrfs: more trivial BTRFS_PATH_AUTO_FREE conversions
Trivial pattern for the auto freeing with goto -> return conversions
if possible.

The following cases are considered trivial in this patch:

1. Cases where there are no operations between btrfs_free_path() and the
   function returns.
2. Cases where only simple cleanup operations (such as kfree(), kvfree(),
   clear_bit(), and fs_path_free()) are present between
   btrfs_free_path() and the function return.

Signed-off-by: Sun YangKai <sunk67188@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-23 08:49:26 +02:00
Qu Wenruo
5fbaae4b85 btrfs: prepare scrub to support bs > ps cases
This involves:

- Migrate scrub_stripe::pages[] to folios[]

- Use btrfs_alloc_folio_array() and folio_put() to alloc above array.

- Migrate scrub_stripe_get_kaddr() and scrub_stripe_get_paddr() to use
  folio interfaces

- Migrate raid56_parity_cache_data_pages() to
  raid56_parity_cache_data_folios()
  Since scrub is the only caller still using pages.

  This helper will copy the folio array contents into rbio::stripe_pages,
  with sector uptodate flags updated.

  And a new ASSERT() to make sure bs > ps cases will not hit this path.

Since most scrub code is based on kaddr/paddr, the migration itself is
pretty straightforward.

And since we're here, also move the loop to set the
stripe_sectors[].uptodate out of the copy loop.
As we always mark all the sectors as uptodate for the data stripe, it's
easier to do in one go, other than doing it inside the copy loop.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-23 08:49:25 +02:00
Qu Wenruo
35aff706dc btrfs: concentrate highmem handling for data verification
Currently for btrfs checksum verification, we do it in the following
pattern:

	kaddr = kmap_local_*();
	ret = btrfs_check_csum_csum(kaddr);
	kunmap_local(kaddr);

It's OK for now, but it's still not following the patterns of helpers
inside linux/highmem.h, which never requires a virt memory address.

In those highmem helpers, they mostly accept a folio, some offset/length
inside the folio, and in the implementation they check if the folio
needs partial kmap, and do the handling.

Inspired by those formal highmem helpers, enhance the highmem handling
of data checksum verification by:

- Rename btrfs_check_sector_csum() to btrfs_check_block_csum()
  To follow the more common term "block" used in all other major
  filesystems.

- Pass a physical address into btrfs_check_block_csum() and
  btrfs_data_csum_ok()
  The physical address is always available even for a highmem page.
  Since it's page frame number << PAGE_SHIFT + offset in page.

  And with that physical address, we can grab the folio covering the
  page, and do extra checks to ensure it covers at least one block.

  This also allows us to do the kmap inside btrfs_check_block_csum().
  This means all the extra HIGHMEM handling will be concentrated into
  btrfs_check_block_csum(), and no callers will need to bother highmem
  by themselves.

- Properly zero out the block if csum mismatch
  Since btrfs_data_csum_ok() only got a paddr, we can not and should not
  use memzero_bvec(), which only accepts single page bvec.
  Instead use paddr to grab the folio and call folio_zero_range()

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-23 08:49:16 +02:00
Thorsten Blum
a7f3dfb829 btrfs: scrub: replace max_t()/min_t() with clamp() in scrub_throttle_dev_io()
Replace max_t() followed by min_t() with a single clamp().

As was pointed by David Laight in
https://lore.kernel.org/linux-btrfs/20250906122458.75dfc8f0@pumpkin/
the calculation may overflow u32 when the input value is too large, so
clamp_t() is not used.  In practice the expected values are in range of
megabytes to gigabytes (throughput limit) so the bug would not happen.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: David Sterba <dsterba@suse.com>
[ Use clamp() and add explanation. ]
Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-23 08:49:16 +02:00
David Sterba
17dc82dc1e btrfs: fix typos in comments and strings
Annual typo fixing pass. Strangely codespell found only about 30% of
what is in this patch, the rest was done manually using text
spellchecker with a custom dictionary of acceptable terms.

Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-23 08:49:16 +02:00
David Sterba
67e78f983e btrfs: convert several int parameters to bool
We're almost done cleaning misused int/bool parameters. Convert a bunch
of them, found by manual grepping.  Note that btrfs_sync_fs() needs an
int as it's mandated by the struct super_operations prototype.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-22 10:54:32 +02:00
David Sterba
0fe04bf132 btrfs: switch RCU helper versions to btrfs_warn()
The RCU protection is now done in the plain helpers, we can remove the
"_in_rcu" and "_rl_in_rcu".

Reviewed-by: Daniel Vacek <neelx@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21 23:56:38 +02:00
David Sterba
9db18fe3ac btrfs: switch RCU helper versions to btrfs_err()
The RCU protection is now done in the plain helpers, we can remove the
"_in_rcu" and "_rl_in_rcu".

Reviewed-by: Daniel Vacek <neelx@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21 23:56:38 +02:00
David Sterba
4013cde56e btrfs: rename err to ret in scrub_submit_extent_sector_read()
Unify naming of return value to the preferred way.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21 23:53:29 +02:00
Linus Torvalds
5ca7fe213b for-6.16-rc3-tag
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Merge tag 'for-6.16-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "Fixes:

   - fix invalid inode pointer dereferences during log replay

   - fix a race between renames and directory logging

   - fix shutting down delayed iput worker

   - fix device byte accounting when dropping chunk

   - in zoned mode, fix offset calculations for DUP profile when
     conventional and sequential zones are used together

  Regression fixes:

   - fix possible double unlock of extent buffer tree (xarray
     conversion)

   - in zoned mode, fix extent buffer refcount when writing out extents
     (xarray conversion)

  Error handling fixes and updates:

   - handle unexpected extent type when replaying log

   - check and warn if there are remaining delayed inodes when putting a
     root

   - fix assertion when building free space tree

   - handle csum tree error with mount option 'rescue=ibadroot'

  Other:

   - error message updates: add prefix to all scrub related messages,
     include other information in messages"

* tag 'for-6.16-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: zoned: fix alloc_offset calculation for partly conventional block groups
  btrfs: handle csum tree error with rescue=ibadroots correctly
  btrfs: fix race between async reclaim worker and close_ctree()
  btrfs: fix assertion when building free space tree
  btrfs: don't silently ignore unexpected extent type when replaying log
  btrfs: fix invalid inode pointer dereferences during log replay
  btrfs: fix double unlock of buffer_tree xarray when releasing subpage eb
  btrfs: update superblock's device bytes_used when dropping chunk
  btrfs: fix a race between renames and directory logging
  btrfs: scrub: add prefix for the error messages
  btrfs: warn if leaking delayed_nodes in btrfs_put_root()
  btrfs: fix delayed ref refcount leak in debug assertion
  btrfs: include root in error message when unlinking inode
  btrfs: don't drop a reference if btrfs_check_write_meta_pointer() fails
2025-06-23 11:16:38 -07:00
Anand Jain
65d5112b4d btrfs: scrub: add prefix for the error messages
Add a "scrub: " prefix to all messages logged by scrub so that it's
easy to filter them from dmesg for analysis.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-06-19 15:19:06 +02:00
Linus Torvalds
5e82ed5ca4 for-6.16-tag
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Merge tag 'for-6.16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
 "Apart from numerous cleanups, there are some performance improvements
  and one minor mount option update. There's one more radix-tree
  conversion (one remaining), and continued work towards enabling large
  folios (almost finished).

  Performance:

   - extent buffer conversion to xarray gains throughput and runtime
     improvements on metadata heavy operations doing writeback (sample
     test shows +50% throughput, -33% runtime)

   - extent io tree cleanups lead to performance improvements by
     avoiding unnecessary searches or repeated searches

   - more efficient extent unpinning when committing transaction
     (estimated run time improvement 3-5%)

  User visible changes:

   - remove standalone mount option 'nologreplay', deprecated in 5.9,
     replacement is 'rescue=nologreplay'

   - in scrub, update reporting, add back device stats message after
     detected errors (accidentally removed during recent refactoring)

  Core:

   - convert extent buffer radix tree to xarray

   - in subpage mode, move block perfect compression out of experimental
     build

   - in zoned mode, introduce sub block groups to allow managing special
     block groups, like the one for relocation or tree-log, to handle
     some corner cases of ENOSPC

   - in scrub, simplify bitmaps for block tracking status

   - continued preparations for large folios:
       - remove assertions for folio order 0
       - add support where missing: compression, buffered write, defrag,
         hole punching, subpage, send

   - fix fsync of files with no hard links not persisting deletion

   - reject tree blocks which are not nodesize aligned, a precaution
     from 4.9 times

   - move transaction abort calls closer to the error sites

   - remove usage of some struct bio_vec internals

   - simplifications in extent map

   - extent IO cleanups and optimizations

   - error handling improvements

   - enhanced ASSERT() macro with optional format strings

   - cleanups:
       - remove unused code
       - naming unifications, dropped __, added prefix
       - merge similar functions
       - use common helpers for various data structures"

* tag 'for-6.16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (198 commits)
  btrfs: move misplaced comment of btrfs_path::keep_locks
  btrfs: remove standalone "nologreplay" mount option
  btrfs: use a single variable to track return value at btrfs_page_mkwrite()
  btrfs: don't return VM_FAULT_SIGBUS on failure to set delalloc for mmap write
  btrfs: simplify early error checking in btrfs_page_mkwrite()
  btrfs: pass true to btrfs_delalloc_release_space() at btrfs_page_mkwrite()
  btrfs: fix wrong start offset for delalloc space release during mmap write
  btrfs: fix harmless race getting delayed ref head count when running delayed refs
  btrfs: log error codes during failures when writing super blocks
  btrfs: simplify error return logic when getting folio at prepare_one_folio()
  btrfs: return real error from __filemap_get_folio() calls
  btrfs: remove superfluous return value check at btrfs_dio_iomap_begin()
  btrfs: fix invalid data space release when truncating block in NOCOW mode
  btrfs: update Kconfig option descriptions
  btrfs: update list of features built under experimental config
  btrfs: send: remove btrfs_debug() calls
  btrfs: use boolean for delalloc argument to btrfs_free_reserved_extent()
  btrfs: use boolean for delalloc argument to btrfs_free_reserved_bytes()
  btrfs: fold error checks when allocating ordered extent and update comments
  btrfs: check we grabbed inode reference when allocating an ordered extent
  ...
2025-05-26 12:24:43 -07:00
Linus Torvalds
6f59de9bc0 for-6.16/block-20250523
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Merge tag 'for-6.16/block-20250523' of git://git.kernel.dk/linux

Pull block updates from Jens Axboe:

 - ublk updates:
      - Add support for updating the size of a ublk instance
      - Zero-copy improvements
      - Auto-registering of buffers for zero-copy
      - Series simplifying and improving GET_DATA and request lookup
      - Series adding quiesce support
      - Lots of selftests additions
      - Various cleanups

 - NVMe updates via Christoph:
      - add per-node DMA pools and use them for PRP/SGL allocations
        (Caleb Sander Mateos, Keith Busch)
      - nvme-fcloop refcounting fixes (Daniel Wagner)
      - support delayed removal of the multipath node and optionally
        support the multipath node for private namespaces (Nilay Shroff)
      - support shared CQs in the PCI endpoint target code (Wilfred
        Mallawa)
      - support admin-queue only authentication (Hannes Reinecke)
      - use the crc32c library instead of the crypto API (Eric Biggers)
      - misc cleanups (Christoph Hellwig, Marcelo Moreira, Hannes
        Reinecke, Leon Romanovsky, Gustavo A. R. Silva)

 - MD updates via Yu:
      - Fix that normal IO can be starved by sync IO, found by mkfs on
        newly created large raid5, with some clean up patches for bdev
        inflight counters

 - Clean up brd, getting rid of atomic kmaps and bvec poking

 - Add loop driver specifically for zoned IO testing

 - Eliminate blk-rq-qos calls with a static key, if not enabled

 - Improve hctx locking for when a plug has IO for multiple queues
   pending

 - Remove block layer bouncing support, which in turn means we can
   remove the per-node bounce stat as well

 - Improve blk-throttle support

 - Improve delay support for blk-throttle

 - Improve brd discard support

 - Unify IO scheduler switching. This should also fix a bunch of lockdep
   warnings we've been seeing, after enabling lockdep support for queue
   freezing/unfreezeing

 - Add support for block write streams via FDP (flexible data placement)
   on NVMe

 - Add a bunch of block helpers, facilitating the removal of a bunch of
   duplicated boilerplate code

 - Remove obsolete BLK_MQ pci and virtio Kconfig options

 - Add atomic/untorn write support to blktrace

 - Various little cleanups and fixes

* tag 'for-6.16/block-20250523' of git://git.kernel.dk/linux: (186 commits)
  selftests: ublk: add test for UBLK_F_QUIESCE
  ublk: add feature UBLK_F_QUIESCE
  selftests: ublk: add test case for UBLK_U_CMD_UPDATE_SIZE
  traceevent/block: Add REQ_ATOMIC flag to block trace events
  ublk: run auto buf unregisgering in same io_ring_ctx with registering
  io_uring: add helper io_uring_cmd_ctx_handle()
  ublk: remove io argument from ublk_auto_buf_reg_fallback()
  ublk: handle ublk_set_auto_buf_reg() failure correctly in ublk_fetch()
  selftests: ublk: add test for covering UBLK_AUTO_BUF_REG_FALLBACK
  selftests: ublk: support UBLK_F_AUTO_BUF_REG
  ublk: support UBLK_AUTO_BUF_REG_FALLBACK
  ublk: register buffer to local io_uring with provided buf index via UBLK_F_AUTO_BUF_REG
  ublk: prepare for supporting to register request buffer automatically
  ublk: convert to refcount_t
  selftests: ublk: make IO & device removal test more stressful
  nvme: rename nvme_mpath_shutdown_disk to nvme_mpath_remove_disk
  nvme: introduce multipath_always_on module param
  nvme-multipath: introduce delayed removal of the multipath head node
  nvme-pci: derive and better document max segments limits
  nvme-pci: use struct_size for allocation struct nvme_dev
  ...
2025-05-26 11:39:36 -07:00
Qu Wenruo
4ad57e1e22 btrfs: scrub: reduce memory usage of struct scrub_sector_verification
That structure records needed info for block verification (either data
checksum pointer, or expected tree block generation).

But there is also a boolean to tell if this block belongs to a metadata
or not, as the data checksum pointer and expected tree block generation
is already a union, we need a dedicated bit to tell if this block is a
metadata or not.

However such layout means we're wasting 63 bits for x86_64, which is a
huge memory waste.

Thanks to the recent bitmap aggregation, we can easily move this
single-bit-per-block member to a new sub-bitmap.
And since we already have six 16 bits long bitmaps, adding another
bitmap won't even increase any memory usage for x86_64, as we need two
64 bits long anyway.

This will reduce the following memory usages:

- sizeof(struct scrub_sector_verification)
  From 16 bytes to 8 bytes on x86_64.

- scrub_stripe::sectors
  From 16 * 16 to 16 * 8 bytes.

- Per-device scrub_ctx memory usage
  From 128 * (16 * 16) to 128 * (16 * 8), which saves 16KiB memory.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15 14:30:56 +02:00
Qu Wenruo
1b660424a6 btrfs: scrub: aggregate small bitmaps into a larger one
Currently we have several small bitmaps inside scrub_stripe:

- extent_sector_bitmap
- error_bitmap
- io_error_bitmap
- csum_error_bitmap
- meta_error_bitmap
- meta_gen_error_bitmap

All those bitmaps are at most 16 bits long, but unsigned long is
either 32 or 64 (more common) bits.

This means we're wasting 1/2 or 3/4 space for each bitmap.

And we can have 128 scrub_stripe for each device, such wasted space adds up
quickly.

Instead of using a single unsigned long for each bitmap, aggregate them
into a larger bitmap, just like what we're doing for subpage support.

This reduces 24 bytes from each scrub_stripe structure on x86_64
systems.

This will need a lot of macros converting direct bitmap/bit operations into
our scrub_stripe specific helpers, but all those helpers are very small
and can be inlined.

So overall the overhead shouldn't be that huge, and we save quite some
memory space.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15 14:30:55 +02:00
Qu Wenruo
f2c19541e4 btrfs: scrub: fix a wrong error type when metadata bytenr mismatches
When the bytenr doesn't match for a metadata tree block, we will report
it as an csum error, which is incorrect and should be reported as a
metadata error instead.

Fixes: a3ddbaebc7 ("btrfs: scrub: introduce a helper to verify one metadata block")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15 14:30:55 +02:00
Qu Wenruo
ce6920dba8 btrfs: scrub: move error reporting members to stack
Currently the following members of scrub_stripe are only utilized for
error reporting:

- init_error_bitmap
- init_nr_io_errors
- init_nr_csum_errors
- init_nr_meta_errors
- init_nr_meta_gen_errors

There is no need to put all those members into scrub_stripe, which take
24 bytes for each stripe, and we have 128 stripes for each device.

Instead introduce a structure, scrub_error_records, and move all above
members into that structure.

And allocate such structure from stack inside
scrub_stripe_read_repair_worker().
Since that function is called from a workqueue context, we have more
than enough stack space for just 24 bytes.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15 14:30:54 +02:00
Qu Wenruo
ec1f3a207c btrfs: scrub: update device stats when an error is detected
[BUG]
Since the migration to the new scrub_stripe interface, scrub no longer
updates the device stats when hitting an error, no matter if it's a read
or checksum mismatch error. E.g:

  BTRFS info (device dm-2): scrub: started on devid 1
  BTRFS error (device dm-2): unable to fixup (regular) error at logical 13631488 on dev /dev/mapper/test-scratch1 physical 13631488
  BTRFS warning (device dm-2): checksum error at logical 13631488 on dev /dev/mapper/test-scratch1, physical 13631488, root 5, inode 257, offset 0, length 4096, links 1 (path: file)
  BTRFS error (device dm-2): unable to fixup (regular) error at logical 13631488 on dev /dev/mapper/test-scratch1 physical 13631488
  BTRFS warning (device dm-2): checksum error at logical 13631488 on dev /dev/mapper/test-scratch1, physical 13631488, root 5, inode 257, offset 0, length 4096, links 1 (path: file)
  BTRFS info (device dm-2): scrub: finished on devid 1 with status: 0

Note there is no line showing the device stats error update.

[CAUSE]
In the migration to the new scrub_stripe interface, we no longer call
btrfs_dev_stat_inc_and_print().

[FIX]
- Introduce a new bitmap for metadata generation errors
  * A new bitmap
    @meta_gen_error_bitmap is introduced to record which blocks have
    metadata generation mismatch errors.

  * A new counter for that bitmap
    @init_nr_meta_gen_errors, is also introduced to store the number of
    generation mismatch errors that are found during the initial read.

    This is for the error reporting at scrub_stripe_report_errors().

  * New dedicated error message for unrepaired generation mismatches

  * Update @meta_gen_error_bitmap if a transid mismatch is hit

- Add btrfs_dev_stat_inc_and_print() calls to the following call sites
  * scrub_stripe_report_errors()
  * scrub_write_endio()
    This is only for the write errors.

This means there is a minor behavior change:

- The timing of device stats error message
  Since we concentrate the error messages at
  scrub_stripe_report_errors(), the device stats error messages will all
  show up in one go, after the detailed scrub error messages:

   BTRFS error (device dm-2): unable to fixup (regular) error at logical 13631488 on dev /dev/mapper/test-scratch1 physical 13631488
   BTRFS warning (device dm-2): checksum error at logical 13631488 on dev /dev/mapper/test-scratch1, physical 13631488, root 5, inode 257, offset 0, length 4096, links 1 (path: file)
   BTRFS error (device dm-2): unable to fixup (regular) error at logical 13631488 on dev /dev/mapper/test-scratch1 physical 13631488
   BTRFS warning (device dm-2): checksum error at logical 13631488 on dev /dev/mapper/test-scratch1, physical 13631488, root 5, inode 257, offset 0, length 4096, links 1 (path: file)
   BTRFS error (device dm-2): bdev /dev/mapper/test-scratch1 errs: wr 0, rd 0, flush 0, corrupt 1, gen 0
   BTRFS error (device dm-2): bdev /dev/mapper/test-scratch1 errs: wr 0, rd 0, flush 0, corrupt 2, gen 0

Fixes: e02ee89baa ("btrfs: scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15 14:30:54 +02:00
Christoph Hellwig
adbfd189c4 btrfs: scrub: use virtual addresses directly
Instead of the old @page and @page_offset pair inside scrub, here we can
directly use the virtual address for a sector.

This has the following benefit:

- Simplified parameters
  A single @kaddr will repair @page and @page_offset.

- No more unnecessary kmap/kunmap calls
  Since all pages utilized by scrub is allocated by scrub, and no
  highmem is allowed, we do not need to do any kmap/kunmap.

  And add an ASSERT() inside the new scrub_stripe_get_kaddr() to
  catch any unexpected highmem page.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15 14:30:47 +02:00
Christoph Hellwig
959ddf2839 btrfs: move kmapping out of btrfs_check_sector_csum()
Move kmapping the page out of btrfs_check_sector_csum().

This allows using bvec_kmap_local() where suitable and reduces the number
of kmap*() calls in the raid56 code.

This also means btrfs_check_sector_csum() will only accept a properly
kmapped address.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15 14:30:46 +02:00
Christoph Hellwig
760aa1818b btrfs: use bdev_rw_virt in scrub_one_super
Replace the code building a bio from a kernel direct map address and
submitting it synchronously with the bdev_rw_virt helper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: David Sterba <dsterba@suse.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Link: https://lore.kernel.org/r/20250507120451.4000627-19-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-07 07:31:07 -06:00
Qu Wenruo
f95d186255 btrfs: avoid NULL pointer dereference if no valid csum tree
[BUG]
When trying read-only scrub on a btrfs with rescue=idatacsums mount
option, it will crash with the following call trace:

  BUG: kernel NULL pointer dereference, address: 0000000000000208
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  CPU: 1 UID: 0 PID: 835 Comm: btrfs Tainted: G           O        6.15.0-rc3-custom+ #236 PREEMPT(full)
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022
  RIP: 0010:btrfs_lookup_csums_bitmap+0x49/0x480 [btrfs]
  Call Trace:
   <TASK>
   scrub_find_fill_first_stripe+0x35b/0x3d0 [btrfs]
   scrub_simple_mirror+0x175/0x290 [btrfs]
   scrub_stripe+0x5f7/0x6f0 [btrfs]
   scrub_chunk+0x9a/0x150 [btrfs]
   scrub_enumerate_chunks+0x333/0x660 [btrfs]
   btrfs_scrub_dev+0x23e/0x600 [btrfs]
   btrfs_ioctl+0x1dcf/0x2f80 [btrfs]
   __x64_sys_ioctl+0x97/0xc0
   do_syscall_64+0x4f/0x120
   entry_SYSCALL_64_after_hwframe+0x76/0x7e

[CAUSE]
Mount option "rescue=idatacsums" will completely skip loading the csum
tree, so that any data read will not find any data csum thus we will
ignore data checksum verification.

Normally call sites utilizing csum tree will check the fs state flag
NO_DATA_CSUMS bit, but unfortunately scrub does not check that bit at all.

This results in scrub to call btrfs_search_slot() on a NULL pointer
and triggered above crash.

[FIX]
Check both extent and csum tree root before doing any tree search.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-02 13:20:11 +02:00