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Commit Graph

1853 Commits

Author SHA1 Message Date
Anand Jain
22fb0d99c9 btrfs: add tracking of read blocks for read policy
Track number of read blocks in the whole filesystem. The counter is
initialized when devices are opened. The counter is increased at
btrfs_submit_dev_bio() if the stats tracking is enabled (depends on the
read policy).  Stats tracking is disabled by default and is enabled
through fs_devices::collect_fs_stats when required.

The code is not under the EXPERIMENTAL define, as stats can be expanded
to include write counts and other performance counters, with the user
interface independent of its internal use.

This is an in-memory-only feature, not related to the dev error stats.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-01-13 14:53:21 +01:00
Anand Jain
a5019b7070 btrfs: initialize fs_devices->fs_info earlier in btrfs_init_devices_late()
Currently, fs_devices->fs_info is initialized in btrfs_init_devices_late(),
but this occurs too late for find_live_mirror(), which is invoked by
load_super_root() much earlier than btrfs_init_devices_late().

Fix this by moving the initialization to open_ctree(), before load_super_root().

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.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>
2025-01-13 14:53:20 +01:00
Qu Wenruo
2a9bb78cfd btrfs: validate system chunk array at btrfs_validate_super()
Currently btrfs_validate_super() only does a very basic check on the
array chunk size (not too large than the available space, but not too
small to contain no chunk).

The more comprehensive checks (the regular chunk checks and size check
inside the system chunk array) are all done inside btrfs_read_sys_array().

It's not a big deal, but it also means we do not do any validation on
the system chunk array at super block writeback time either.

Do the following modification to centralize the system chunk array
checks into btrfs_validate_super():

- Make chunk_err() helper accept stack chunk pointer
  If @leaf parameter is NULL, then the @chunk pointer will be a pointer
  to the chunk item, other than the offset inside the leaf.

  And since @leaf can be NULL, add a new @fs_info parameter for that
  case.

- Make btrfs_check_chunk_valid() handle stack chunk pointer
  The same as chunk_err(), a new @fs_info parameter, and if @leaf is
  NULL, then @chunk will be a pointer to a stack chunk.

  If @chunk is NULL, then all needed btrfs_chunk members will be read
  using the stack helper instead of the leaf helper.
  This means we need to read out all the needed member at the beginning
  of the function.

  Furthermore, at super block read time, fs_info->sectorsize is not yet
  initialized, we need one extra @sectorsize parameter to grab the
  correct sectorsize.

- Introduce a helper validate_sys_chunk_array()
  * Validate the disk key.
  * Validate the size before we access the full chunk items.
  * Do the full chunk item validation.

- Call validate_sys_chunk_array() at btrfs_validate_super()

- Simplify the checks inside btrfs_read_sys_array()
  Now the checks will be converted to an ASSERT().

- Simplify the checks inside read_one_chunk()
  Now that all chunk items inside system chunk array and chunk tree are
  verified, there is no need to verify them again inside read_one_chunk().

This change has the following advantages:

- More comprehensive checks at write time
  And unlike the sys_chunk_array read routine, this time we do not need
  to allocate a dummy extent buffer to do the check.
  All the checks done here require no new memory allocation.

- Slightly improved readability when iterating the system chunk array

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-01-13 14:53:18 +01:00
Filipe Manana
f10bef73fb btrfs: flush delalloc workers queue before stopping cleaner kthread during unmount
During the unmount path, at close_ctree(), we first stop the cleaner
kthread, using kthread_stop() which frees the associated task_struct, and
then stop and destroy all the work queues. However after we stopped the
cleaner we may still have a worker from the delalloc_workers queue running
inode.c:submit_compressed_extents(), which calls btrfs_add_delayed_iput(),
which in turn tries to wake up the cleaner kthread - which was already
destroyed before, resulting in a use-after-free on the task_struct.

Syzbot reported this with the following stack traces:

  BUG: KASAN: slab-use-after-free in __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
  Read of size 8 at addr ffff8880259d2818 by task kworker/u8:3/52

  CPU: 1 UID: 0 PID: 52 Comm: kworker/u8:3 Not tainted 6.13.0-rc1-syzkaller-00002-gcdd30ebb1b9f #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
  Workqueue: btrfs-delalloc btrfs_work_helper
  Call Trace:
   <TASK>
   __dump_stack lib/dump_stack.c:94 [inline]
   dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
   print_address_description mm/kasan/report.c:378 [inline]
   print_report+0x169/0x550 mm/kasan/report.c:489
   kasan_report+0x143/0x180 mm/kasan/report.c:602
   __lock_acquire+0x78/0x2100 kernel/locking/lockdep.c:5089
   lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
   _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
   class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline]
   try_to_wake_up+0xc2/0x1470 kernel/sched/core.c:4205
   submit_compressed_extents+0xdf/0x16e0 fs/btrfs/inode.c:1615
   run_ordered_work fs/btrfs/async-thread.c:288 [inline]
   btrfs_work_helper+0x96f/0xc40 fs/btrfs/async-thread.c:324
   process_one_work kernel/workqueue.c:3229 [inline]
   process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
   worker_thread+0x870/0xd30 kernel/workqueue.c:3391
   kthread+0x2f0/0x390 kernel/kthread.c:389
   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
   </TASK>

  Allocated by task 2:
   kasan_save_stack mm/kasan/common.c:47 [inline]
   kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
   unpoison_slab_object mm/kasan/common.c:319 [inline]
   __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
   kasan_slab_alloc include/linux/kasan.h:250 [inline]
   slab_post_alloc_hook mm/slub.c:4104 [inline]
   slab_alloc_node mm/slub.c:4153 [inline]
   kmem_cache_alloc_node_noprof+0x1d9/0x380 mm/slub.c:4205
   alloc_task_struct_node kernel/fork.c:180 [inline]
   dup_task_struct+0x57/0x8c0 kernel/fork.c:1113
   copy_process+0x5d1/0x3d50 kernel/fork.c:2225
   kernel_clone+0x223/0x870 kernel/fork.c:2807
   kernel_thread+0x1bc/0x240 kernel/fork.c:2869
   create_kthread kernel/kthread.c:412 [inline]
   kthreadd+0x60d/0x810 kernel/kthread.c:767
   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

  Freed by task 24:
   kasan_save_stack mm/kasan/common.c:47 [inline]
   kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
   kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582
   poison_slab_object mm/kasan/common.c:247 [inline]
   __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
   kasan_slab_free include/linux/kasan.h:233 [inline]
   slab_free_hook mm/slub.c:2338 [inline]
   slab_free mm/slub.c:4598 [inline]
   kmem_cache_free+0x195/0x410 mm/slub.c:4700
   put_task_struct include/linux/sched/task.h:144 [inline]
   delayed_put_task_struct+0x125/0x300 kernel/exit.c:227
   rcu_do_batch kernel/rcu/tree.c:2567 [inline]
   rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
   handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:554
   run_ksoftirqd+0xca/0x130 kernel/softirq.c:943
   smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164
   kthread+0x2f0/0x390 kernel/kthread.c:389
   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

  Last potentially related work creation:
   kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
   __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:544
   __call_rcu_common kernel/rcu/tree.c:3086 [inline]
   call_rcu+0x167/0xa70 kernel/rcu/tree.c:3190
   context_switch kernel/sched/core.c:5372 [inline]
   __schedule+0x1803/0x4be0 kernel/sched/core.c:6756
   __schedule_loop kernel/sched/core.c:6833 [inline]
   schedule+0x14b/0x320 kernel/sched/core.c:6848
   schedule_timeout+0xb0/0x290 kernel/time/sleep_timeout.c:75
   do_wait_for_common kernel/sched/completion.c:95 [inline]
   __wait_for_common kernel/sched/completion.c:116 [inline]
   wait_for_common kernel/sched/completion.c:127 [inline]
   wait_for_completion+0x355/0x620 kernel/sched/completion.c:148
   kthread_stop+0x19e/0x640 kernel/kthread.c:712
   close_ctree+0x524/0xd60 fs/btrfs/disk-io.c:4328
   generic_shutdown_super+0x139/0x2d0 fs/super.c:642
   kill_anon_super+0x3b/0x70 fs/super.c:1237
   btrfs_kill_super+0x41/0x50 fs/btrfs/super.c:2112
   deactivate_locked_super+0xc4/0x130 fs/super.c:473
   cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1373
   task_work_run+0x24f/0x310 kernel/task_work.c:239
   ptrace_notify+0x2d2/0x380 kernel/signal.c:2503
   ptrace_report_syscall include/linux/ptrace.h:415 [inline]
   ptrace_report_syscall_exit include/linux/ptrace.h:477 [inline]
   syscall_exit_work+0xc7/0x1d0 kernel/entry/common.c:173
   syscall_exit_to_user_mode_prepare kernel/entry/common.c:200 [inline]
   __syscall_exit_to_user_mode_work kernel/entry/common.c:205 [inline]
   syscall_exit_to_user_mode+0x24a/0x340 kernel/entry/common.c:218
   do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

  The buggy address belongs to the object at ffff8880259d1e00
   which belongs to the cache task_struct of size 7424
  The buggy address is located 2584 bytes inside of
   freed 7424-byte region [ffff8880259d1e00, ffff8880259d3b00)

  The buggy address belongs to the physical page:
  page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x259d0
  head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
  memcg:ffff88802f4b56c1
  flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
  page_type: f5(slab)
  raw: 00fff00000000040 ffff88801bafe500 dead000000000100 dead000000000122
  raw: 0000000000000000 0000000000040004 00000001f5000000 ffff88802f4b56c1
  head: 00fff00000000040 ffff88801bafe500 dead000000000100 dead000000000122
  head: 0000000000000000 0000000000040004 00000001f5000000 ffff88802f4b56c1
  head: 00fff00000000003 ffffea0000967401 ffffffffffffffff 0000000000000000
  head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
  page dumped because: kasan: bad access detected
  page_owner tracks the page as allocated
  page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 12, tgid 12 (kworker/u8:1), ts 7328037942, free_ts 0
   set_page_owner include/linux/page_owner.h:32 [inline]
   post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556
   prep_new_page mm/page_alloc.c:1564 [inline]
   get_page_from_freelist+0x3651/0x37a0 mm/page_alloc.c:3474
   __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4751
   alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
   alloc_slab_page+0x6a/0x140 mm/slub.c:2408
   allocate_slab+0x5a/0x2f0 mm/slub.c:2574
   new_slab mm/slub.c:2627 [inline]
   ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3815
   __slab_alloc+0x58/0xa0 mm/slub.c:3905
   __slab_alloc_node mm/slub.c:3980 [inline]
   slab_alloc_node mm/slub.c:4141 [inline]
   kmem_cache_alloc_node_noprof+0x269/0x380 mm/slub.c:4205
   alloc_task_struct_node kernel/fork.c:180 [inline]
   dup_task_struct+0x57/0x8c0 kernel/fork.c:1113
   copy_process+0x5d1/0x3d50 kernel/fork.c:2225
   kernel_clone+0x223/0x870 kernel/fork.c:2807
   user_mode_thread+0x132/0x1a0 kernel/fork.c:2885
   call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
   process_one_work kernel/workqueue.c:3229 [inline]
   process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
   worker_thread+0x870/0xd30 kernel/workqueue.c:3391
  page_owner free stack trace missing

  Memory state around the buggy address:
   ffff8880259d2700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
   ffff8880259d2780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  >ffff8880259d2800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                              ^
   ffff8880259d2880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
   ffff8880259d2900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ==================================================================

Fix this by flushing the delalloc workers queue before stopping the
cleaner kthread.

Reported-by: syzbot+b7cf50a0c173770dcb14@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/674ed7e8.050a0220.48a03.0031.GAE@google.com/
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-12-06 15:04:18 +01:00
Filipe Manana
c3a5888e0f btrfs: remove fs_info parameter from btrfs_cleanup_one_transaction()
The fs_info parameter is redundant because it can be extracted from the
transaction given as another parameter. So remove it and use the fs_info
accessible from the transaction.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11 14:34:19 +01:00
Filipe Manana
2f6e05a5cc btrfs: remove fs_info parameter from btrfs_destroy_delayed_refs()
The fs_info parameter is redundant because it can be extracted from the
transaction given as another parameter. So remove it and use the fs_info
accessible from the transaction.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11 14:34:19 +01:00
Filipe Manana
22a0ae1889 btrfs: move btrfs_destroy_delayed_refs() to delayed-ref.c
It's better suited at delayed-ref.c since it's about delayed refs and
contains logic to iterate over them (using the red black tree, doing all
the locking, freeing, etc), so move it from disk-io.c, which is pretty
big, into delayed-ref.c, hiding implementation details of how delayed
refs are tracked and managed. This also facilitates the next patches in
the series.

This change moves the code between files but also does the following
simple cleanups:

1) Rename the 'cache' variable to 'bg', since it's a block group
   (the 'cache' logic comes from old days where the block group
   structure was named 'btrfs_block_group_cache');

2) Move the 'ref' variable declaration to the scope of the inner
   while loop, since it's not used outside that loop.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11 14:34:19 +01:00
Filipe Manana
00f529661b btrfs: remove BUG_ON() at btrfs_destroy_delayed_refs()
At btrfs_destroy_delayed_refs() it's unexpected to not find the block
group to which a delayed reference's extent belongs to, so we have this
BUG_ON(), not just because it's highly unexpected but also because we
don't know what to do there.

Since we are in the transaction abort path, there's nothing we can do
other than proceed and cleanup all used resources we can. So remove
the BUG_ON() and deal with a missing block group by logging an error
message and continuing to cleanup all we can related to the current
delayed ref head and moving to other delayed refs.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11 14:34:19 +01:00
Filipe Manana
e7fa845010 btrfs: rename extent map shrinker members from struct btrfs_fs_info
The names for the members of struct btrfs_fs_info related to the extent
map shrinker are a bit too long, so rename them to be shorter by replacing
the "extent_map_" prefix with the "em_" prefix.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11 14:34:17 +01:00
Filipe Manana
70a5f9e266 btrfs: simplify tracking progress for the extent map shrinker
Now that the extent map shrinker can only be run by a single task (as a
work queue item) there is no need to keep the progress of the shrinker
protected by a spinlock and passing the progress to trace events as
parameters. So remove the lock and simplify the arguments for the trace
events.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11 14:34:17 +01:00
Filipe Manana
1020443840 btrfs: make the extent map shrinker run asynchronously as a work queue job
Currently the extent map shrinker is run synchronously for kswapd tasks
that end up calling the fs shrinker (fs/super.c:super_cache_scan()).
This has some disadvantages and for some heavy workloads with memory
pressure it can cause some delays and stalls that make a machine
unresponsive for some periods. This happens because:

1) We can have several kswapd tasks on machines with multiple NUMA zones,
   and running the extent map shrinker concurrently can cause high
   contention on some spin locks, namely the spin locks that protect
   the radix tree that tracks roots, the per root xarray that tracks
   open inodes and the list of delayed iputs. This not only delays the
   shrinker but also causes high CPU consumption and makes the task
   running the shrinker monopolize a core, resulting in the symptoms
   of an unresponsive system. This was noted in previous commits such as
   commit ae1e766f62 ("btrfs: only run the extent map shrinker from
   kswapd tasks");

2) The extent map shrinker's iteration over inodes can often be slow, even
   after changing the data structure that tracks open inodes for a root
   from a red black tree (up to kernel 6.10) to an xarray (kernel 6.10+).
   The transition to the xarray while it made things a bit faster, it's
   still somewhat slow - for example in a test scenario with 10000 inodes
   that have no extent maps loaded, the extent map shrinker took between
   5ms to 8ms, using a release, non-debug kernel. Iterating over the
   extent maps of an inode can also be slow if have an inode with many
   thousands of extent maps, since we use a red black tree to track and
   search extent maps. So having the extent map shrinker run synchronously
   adds extra delay for other things a kswapd task does.

So make the extent map shrinker run asynchronously as a job for the
system unbounded workqueue, just like what we do for data and metadata
space reclaim jobs.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11 14:34:17 +01:00
David Sterba
d12a1a2a30 btrfs: drop unused parameter transaction from alloc_log_tree()
The function got split in commit 6ab6ebb760 ("btrfs: split
alloc_log_tree()") and since then transaction parameter has been unused.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11 14:34:17 +01:00
David Sterba
87cbab8636 btrfs: drop unused parameter options from open_ctree()
Since the new mount option parser in commit ad21f15b0f ("btrfs:
switch to the new mount API") we don't pass the options like that
anymore.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11 14:34:17 +01:00
Linus Torvalds
4e46774408 for-6.12-rc4-tag
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Merge tag 'for-6.12-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - mount option fixes:
     - fix handling of compression mount options on remount
     - reject rw remount in case there are options that don't work
       in read-write mode (like rescue options)

 - fix zone accounting of unusable space

 - fix in-memory corruption when merging extent maps

 - fix delalloc range locking for sector < page

 - use more convenient default value of drop subtree threshold, clean
   more subvolumes without the fallback to marking quotas inconsistent

 - fix smatch warning about incorrect value passed to ERR_PTR

* tag 'for-6.12-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix passing 0 to ERR_PTR in btrfs_search_dir_index_item()
  btrfs: reject ro->rw reconfiguration if there are hard ro requirements
  btrfs: fix read corruption due to race with extent map merging
  btrfs: fix the delalloc range locking if sector size < page size
  btrfs: qgroup: set a more sane default value for subtree drop threshold
  btrfs: clear force-compress on remount when compress mount option is given
  btrfs: zoned: fix zone unusable accounting for freed reserved extent
2024-10-24 13:04:15 -07:00
Qu Wenruo
5f9062a48d btrfs: qgroup: set a more sane default value for subtree drop threshold
Since commit 011b46c304 ("btrfs: skip subtree scan if it's too high to
avoid low stall in btrfs_commit_transaction()"), btrfs qgroup can
automatically skip large subtree scan at the cost of marking qgroup
inconsistent.

It's designed to address the final performance problem of snapshot drop
with qgroup enabled, but to be safe the default value is
BTRFS_MAX_LEVEL, requiring a user space daemon to set a different value
to make it work.

I'd say it's not a good idea to rely on user space tool to set this
default value, especially when some operations (snapshot dropping) can
be triggered immediately after mount, leaving a very small window to
that that sysfs interface.

So instead of disabling this new feature by default, enable it with a
low threshold (3), so that large subvolume tree drop at mount time won't
cause huge qgroup workload.

CC: stable@vger.kernel.org # 6.1
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-10-22 16:09:11 +02:00
Linus Torvalds
79eb2c07af for-6.12-rc1-tag
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Merge tag 'for-6.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - in incremental send, fix invalid clone operation for file that got
   its size decreased

 - fix __counted_by() annotation of send path cache entries, we do not
   store the terminating NUL

 - fix a longstanding bug in relocation (and quite hard to hit by
   chance), drop back reference cache that can get out of sync after
   transaction commit

 - wait for fixup worker kthread before finishing umount

 - add missing raid-stripe-tree extent for NOCOW files, zoned mode
   cannot have NOCOW files but RST is meant to be a standalone feature

 - handle transaction start error during relocation, avoid potential
   NULL pointer dereference of relocation control structure (reported by
   syzbot)

 - disable module-wide rate limiting of debug level messages

 - minor fix to tracepoint definition (reported by checkpatch.pl)

* tag 'for-6.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: disable rate limiting when debug enabled
  btrfs: wait for fixup workers before stopping cleaner kthread during umount
  btrfs: fix a NULL pointer dereference when failed to start a new trasacntion
  btrfs: send: fix invalid clone operation for file that got its size decreased
  btrfs: tracepoints: end assignment with semicolon at btrfs_qgroup_extent event class
  btrfs: drop the backref cache during relocation if we commit
  btrfs: also add stripe entries for NOCOW writes
  btrfs: send: fix buffer overflow detection when copying path to cache entry
2024-10-04 10:05:13 -07:00
Al Viro
5f60d5f6bb move asm/unaligned.h to linux/unaligned.h
asm/unaligned.h is always an include of asm-generic/unaligned.h;
might as well move that thing to linux/unaligned.h and include
that - there's nothing arch-specific in that header.

auto-generated by the following:

for i in `git grep -l -w asm/unaligned.h`; do
	sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i
done
for i in `git grep -l -w asm-generic/unaligned.h`; do
	sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i
done
git mv include/asm-generic/unaligned.h include/linux/unaligned.h
git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h
sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild
sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h
2024-10-02 17:23:23 -04:00
Filipe Manana
41fd1e9406 btrfs: wait for fixup workers before stopping cleaner kthread during umount
During unmount, at close_ctree(), we have the following steps in this order:

1) Park the cleaner kthread - this doesn't destroy the kthread, it basically
   halts its execution (wake ups against it work but do nothing);

2) We stop the cleaner kthread - this results in freeing the respective
   struct task_struct;

3) We call btrfs_stop_all_workers() which waits for any jobs running in all
   the work queues and then free the work queues.

Syzbot reported a case where a fixup worker resulted in a crash when doing
a delayed iput on its inode while attempting to wake up the cleaner at
btrfs_add_delayed_iput(), because the task_struct of the cleaner kthread
was already freed. This can happen during unmount because we don't wait
for any fixup workers still running before we call kthread_stop() against
the cleaner kthread, which stops and free all its resources.

Fix this by waiting for any fixup workers at close_ctree() before we call
kthread_stop() against the cleaner and run pending delayed iputs.

The stack traces reported by syzbot were the following:

  BUG: KASAN: slab-use-after-free in __lock_acquire+0x77/0x2050 kernel/locking/lockdep.c:5065
  Read of size 8 at addr ffff8880272a8a18 by task kworker/u8:3/52

  CPU: 1 UID: 0 PID: 52 Comm: kworker/u8:3 Not tainted 6.12.0-rc1-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
  Workqueue: btrfs-fixup btrfs_work_helper
  Call Trace:
   <TASK>
   __dump_stack lib/dump_stack.c:94 [inline]
   dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
   print_address_description mm/kasan/report.c:377 [inline]
   print_report+0x169/0x550 mm/kasan/report.c:488
   kasan_report+0x143/0x180 mm/kasan/report.c:601
   __lock_acquire+0x77/0x2050 kernel/locking/lockdep.c:5065
   lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
   _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
   class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline]
   try_to_wake_up+0xb0/0x1480 kernel/sched/core.c:4154
   btrfs_writepage_fixup_worker+0xc16/0xdf0 fs/btrfs/inode.c:2842
   btrfs_work_helper+0x390/0xc50 fs/btrfs/async-thread.c:314
   process_one_work kernel/workqueue.c:3229 [inline]
   process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310
   worker_thread+0x870/0xd30 kernel/workqueue.c:3391
   kthread+0x2f0/0x390 kernel/kthread.c:389
   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
   </TASK>

  Allocated by task 2:
   kasan_save_stack mm/kasan/common.c:47 [inline]
   kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
   unpoison_slab_object mm/kasan/common.c:319 [inline]
   __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
   kasan_slab_alloc include/linux/kasan.h:247 [inline]
   slab_post_alloc_hook mm/slub.c:4086 [inline]
   slab_alloc_node mm/slub.c:4135 [inline]
   kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4187
   alloc_task_struct_node kernel/fork.c:180 [inline]
   dup_task_struct+0x57/0x8c0 kernel/fork.c:1107
   copy_process+0x5d1/0x3d50 kernel/fork.c:2206
   kernel_clone+0x223/0x880 kernel/fork.c:2787
   kernel_thread+0x1bc/0x240 kernel/fork.c:2849
   create_kthread kernel/kthread.c:412 [inline]
   kthreadd+0x60d/0x810 kernel/kthread.c:765
   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

  Freed by task 61:
   kasan_save_stack mm/kasan/common.c:47 [inline]
   kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
   kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
   poison_slab_object mm/kasan/common.c:247 [inline]
   __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
   kasan_slab_free include/linux/kasan.h:230 [inline]
   slab_free_hook mm/slub.c:2343 [inline]
   slab_free mm/slub.c:4580 [inline]
   kmem_cache_free+0x1a2/0x420 mm/slub.c:4682
   put_task_struct include/linux/sched/task.h:144 [inline]
   delayed_put_task_struct+0x125/0x300 kernel/exit.c:228
   rcu_do_batch kernel/rcu/tree.c:2567 [inline]
   rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
   handle_softirqs+0x2c5/0x980 kernel/softirq.c:554
   __do_softirq kernel/softirq.c:588 [inline]
   invoke_softirq kernel/softirq.c:428 [inline]
   __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
   irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
   instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline]
   sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1037
   asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

  Last potentially related work creation:
   kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
   __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
   __call_rcu_common kernel/rcu/tree.c:3086 [inline]
   call_rcu+0x167/0xa70 kernel/rcu/tree.c:3190
   context_switch kernel/sched/core.c:5318 [inline]
   __schedule+0x184b/0x4ae0 kernel/sched/core.c:6675
   schedule_idle+0x56/0x90 kernel/sched/core.c:6793
   do_idle+0x56a/0x5d0 kernel/sched/idle.c:354
   cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:424
   start_secondary+0x102/0x110 arch/x86/kernel/smpboot.c:314
   common_startup_64+0x13e/0x147

  The buggy address belongs to the object at ffff8880272a8000
   which belongs to the cache task_struct of size 7424
  The buggy address is located 2584 bytes inside of
   freed 7424-byte region [ffff8880272a8000, ffff8880272a9d00)

  The buggy address belongs to the physical page:
  page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x272a8
  head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
  flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
  page_type: f5(slab)
  raw: 00fff00000000040 ffff88801bafa500 dead000000000122 0000000000000000
  raw: 0000000000000000 0000000080040004 00000001f5000000 0000000000000000
  head: 00fff00000000040 ffff88801bafa500 dead000000000122 0000000000000000
  head: 0000000000000000 0000000080040004 00000001f5000000 0000000000000000
  head: 00fff00000000003 ffffea00009caa01 ffffffffffffffff 0000000000000000
  head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
  page dumped because: kasan: bad access detected
  page_owner tracks the page as allocated
  page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2, tgid 2 (kthreadd), ts 71247381401, free_ts 71214998153
   set_page_owner include/linux/page_owner.h:32 [inline]
   post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1537
   prep_new_page mm/page_alloc.c:1545 [inline]
   get_page_from_freelist+0x3039/0x3180 mm/page_alloc.c:3457
   __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4733
   alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
   alloc_slab_page+0x6a/0x120 mm/slub.c:2413
   allocate_slab+0x5a/0x2f0 mm/slub.c:2579
   new_slab mm/slub.c:2632 [inline]
   ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3819
   __slab_alloc+0x58/0xa0 mm/slub.c:3909
   __slab_alloc_node mm/slub.c:3962 [inline]
   slab_alloc_node mm/slub.c:4123 [inline]
   kmem_cache_alloc_node_noprof+0x1fe/0x320 mm/slub.c:4187
   alloc_task_struct_node kernel/fork.c:180 [inline]
   dup_task_struct+0x57/0x8c0 kernel/fork.c:1107
   copy_process+0x5d1/0x3d50 kernel/fork.c:2206
   kernel_clone+0x223/0x880 kernel/fork.c:2787
   kernel_thread+0x1bc/0x240 kernel/fork.c:2849
   create_kthread kernel/kthread.c:412 [inline]
   kthreadd+0x60d/0x810 kernel/kthread.c:765
   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
  page last free pid 5230 tgid 5230 stack trace:
   reset_page_owner include/linux/page_owner.h:25 [inline]
   free_pages_prepare mm/page_alloc.c:1108 [inline]
   free_unref_page+0xcd0/0xf00 mm/page_alloc.c:2638
   discard_slab mm/slub.c:2678 [inline]
   __put_partials+0xeb/0x130 mm/slub.c:3146
   put_cpu_partial+0x17c/0x250 mm/slub.c:3221
   __slab_free+0x2ea/0x3d0 mm/slub.c:4450
   qlink_free mm/kasan/quarantine.c:163 [inline]
   qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
   kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
   __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
   kasan_slab_alloc include/linux/kasan.h:247 [inline]
   slab_post_alloc_hook mm/slub.c:4086 [inline]
   slab_alloc_node mm/slub.c:4135 [inline]
   kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4142
   getname_flags+0xb7/0x540 fs/namei.c:139
   do_sys_openat2+0xd2/0x1d0 fs/open.c:1409
   do_sys_open fs/open.c:1430 [inline]
   __do_sys_openat fs/open.c:1446 [inline]
   __se_sys_openat fs/open.c:1441 [inline]
   __x64_sys_openat+0x247/0x2a0 fs/open.c:1441
   do_syscall_x64 arch/x86/entry/common.c:52 [inline]
   do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

  Memory state around the buggy address:
   ffff8880272a8900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
   ffff8880272a8980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  >ffff8880272a8a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                              ^
   ffff8880272a8a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
   ffff8880272a8b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ==================================================================

Reported-by: syzbot+8aaf2df2ef0164ffe1fb@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/66fb36b1.050a0220.aab67.003b.GAE@google.com/
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-10-01 19:29:33 +02:00
Li Zetao
b8ae2bfa68 btrfs: convert try_release_extent_buffer() to take a folio
The old page API is being gradually replaced and converted to use folio
to improve code readability and avoid repeated conversion between page
and folio.

Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-09-10 16:51:20 +02:00
Qu Wenruo
ce4a71ee15 btrfs: subpage: remove btrfs_fs_info::subpage_info member
The member btrfs_fs_info::subpage_info stores the cached bitmap start
position inside the merged bitmap.

However in reality there is only one thing depending on the sectorsize,
bitmap_nr_bits, which records the number of sectors that fit inside a
page.

The sequence of sub-bitmaps have fixed order, thus it's just a quick
multiplication to calculate the start position of each sub-bitmaps.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-09-10 16:51:18 +02:00
Linus Torvalds
a1b547f0f2 for-6.11-tag
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Merge tag 'for-6.11-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs updates from David Sterba:
 "The highlights are new logic behind background block group reclaim,
  automatic removal of qgroup after removing a subvolume and new
  'rescue=' mount options.

  The rest is optimizations, cleanups and refactoring.

  User visible features:

   - dynamic block group reclaim:
      - tunable framework to avoid situations where eager data
        allocations prevent creating new metadata chunks due to lack of
        unallocated space
      - reuse sysfs knob bg_reclaim_threshold (otherwise used only in
        zoned mode) for a fixed value threshold
      - new on/off sysfs knob "dynamic_reclaim" calculating the value
        based on heuristics, aiming to keep spare working space for
        relocating chunks but not to needlessly relocate partially
        utilized block groups or reclaim newly allocated ones
      - stats are exported in sysfs per block group type, files
        "reclaim_*"
      - this may increase IO load at unexpected times but the corner
        case of no allocatable block groups is known to be worse

   - automatically remove qgroup of deleted subvolumes:
      - adjust qgroup removal conditions, make sure all related
        subvolume data are already removed, or return EBUSY, also take
        into account setting of sysfs drop_subtree_threshold
      - also works in squota mode

   - mount option updates: new modes of 'rescue=' that allow to mount
     images (read-only) that could have been partially converted by user
     space tools
      - ignoremetacsums  - invalid metadata checksums are ignored
      - ignoresuperflags - super block flags that track conversion in
                           progress (like UUID or checksums)

  Core:

   - size of struct btrfs_inode is now below 1024 (on a release config),
     improved memory packing and other secondary effects

   - switch tracking of open inodes from rb-tree to xarray, minor
     performance improvement

   - reduce number of empty transaction commits when there are no dirty
     data/metadata

   - memory allocation optimizations (reduced numbers, reordering out of
     critical sections)

   - extent map structure optimizations and refactoring, more sanity
     checks

   - more subpage in zoned mode preparations or fixes

   - general snapshot code cleanups, improvements and documentation

   - tree-checker updates: more file extent ram_bytes fixes, continued

   - raid-stripe-tree update (not backward compatible):
      - remove extent encoding field from the structure, can be inferred
        from other information
      - requires btrfs-progs 6.9.1 or newer

   - cleanups and refactoring
      - error message updates
      - error handling improvements
      - return type and parameter cleanups and improvements"

* tag 'for-6.11-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (152 commits)
  btrfs: fix extent map use-after-free when adding pages to compressed bio
  btrfs: fix bitmap leak when loading free space cache on duplicate entry
  btrfs: remove the BUG_ON() inside extent_range_clear_dirty_for_io()
  btrfs: move extent_range_clear_dirty_for_io() into inode.c
  btrfs: enhance compression error messages
  btrfs: fix data race when accessing the last_trans field of a root
  btrfs: rename the extra_gfp parameter of btrfs_alloc_page_array()
  btrfs: remove the extra_gfp parameter from btrfs_alloc_folio_array()
  btrfs: introduce new "rescue=ignoresuperflags" mount option
  btrfs: introduce new "rescue=ignoremetacsums" mount option
  btrfs: output the unrecognized super block flags as hex
  btrfs: remove unused Opt enums
  btrfs: tree-checker: add extra ram_bytes and disk_num_bytes check
  btrfs: fix the ram_bytes assignment for truncated ordered extents
  btrfs: make validate_extent_map() catch ram_bytes mismatch
  btrfs: ignore incorrect btrfs_file_extent_item::ram_bytes
  btrfs: cleanup the bytenr usage inside btrfs_extent_item_to_extent_map()
  btrfs: fix typo in error message in btrfs_validate_super()
  btrfs: move the direct IO code into its own file
  btrfs: pass a btrfs_inode to btrfs_set_prop()
  ...
2024-07-17 12:38:04 -07:00
Linus Torvalds
975f3b6da1 for-6.10-rc7-tag
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Merge tag 'for-6.10-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "Fix a regression in extent map shrinker behaviour.

  In the past weeks we got reports from users that there are huge
  latency spikes or freezes. This was bisected to newly added shrinker
  of extent maps (it was added to fix a build up of the structures in
  memory).

  I'm assuming that the freezes would happen to many users after release
  so I'd like to get it merged now so it's in 6.10. Although the diff
  size is not small the changes are relatively straightforward, the
  reporters verified the fixes and we did testing on our side.

  The fixes:

   - adjust behaviour under memory pressure and check lock or scheduling
     conditions, bail out if needed

   - synchronize tracking of the scanning progress so inode ranges are
     not skipped or work duplicated

   - do a delayed iput when scanning a root so evicting an inode does
     not slow things down in case of lots of dirty data, also fix
     lockdep warning, a deadlock could happen when writing the dirty
     data would need to start a transaction"

* tag 'for-6.10-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: avoid races when tracking progress for extent map shrinking
  btrfs: stop extent map shrinker if reschedule is needed
  btrfs: use delayed iput during extent map shrinking
2024-07-12 12:08:42 -07:00
Filipe Manana
4484940514 btrfs: avoid races when tracking progress for extent map shrinking
We store the progress (root and inode numbers) of the extent map shrinker
in fs_info without any synchronization but we can have multiple tasks
calling into the shrinker during memory allocations when there's enough
memory pressure for example.

This can result in a task A reading fs_info->extent_map_shrinker_last_ino
after another task B updates it, and task A reading
fs_info->extent_map_shrinker_last_root before task B updates it, making
task A see an odd state that isn't necessarily harmful but may make it
skip certain inode ranges or do more work than necessary by going over
the same inodes again. These unprotected accesses would also trigger
warnings from tools like KCSAN.

So add a lock to protect access to these progress fields.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 16:50:54 +02:00
Filipe Manana
ca84529a84 btrfs: fix data race when accessing the last_trans field of a root
KCSAN complains about a data race when accessing the last_trans field of a
root:

  [  199.553628] BUG: KCSAN: data-race in btrfs_record_root_in_trans [btrfs] / record_root_in_trans [btrfs]

  [  199.555186] read to 0x000000008801e308 of 8 bytes by task 2812 on cpu 1:
  [  199.555210]  btrfs_record_root_in_trans+0x9a/0x128 [btrfs]
  [  199.555999]  start_transaction+0x154/0xcd8 [btrfs]
  [  199.556780]  btrfs_join_transaction+0x44/0x60 [btrfs]
  [  199.557559]  btrfs_dirty_inode+0x9c/0x140 [btrfs]
  [  199.558339]  btrfs_update_time+0x8c/0xb0 [btrfs]
  [  199.559123]  touch_atime+0x16c/0x1e0
  [  199.559151]  pipe_read+0x6a8/0x7d0
  [  199.559179]  vfs_read+0x466/0x498
  [  199.559204]  ksys_read+0x108/0x150
  [  199.559230]  __s390x_sys_read+0x68/0x88
  [  199.559257]  do_syscall+0x1c6/0x210
  [  199.559286]  __do_syscall+0xc8/0xf0
  [  199.559318]  system_call+0x70/0x98

  [  199.559431] write to 0x000000008801e308 of 8 bytes by task 2808 on cpu 0:
  [  199.559464]  record_root_in_trans+0x196/0x228 [btrfs]
  [  199.560236]  btrfs_record_root_in_trans+0xfe/0x128 [btrfs]
  [  199.561097]  start_transaction+0x154/0xcd8 [btrfs]
  [  199.561927]  btrfs_join_transaction+0x44/0x60 [btrfs]
  [  199.562700]  btrfs_dirty_inode+0x9c/0x140 [btrfs]
  [  199.563493]  btrfs_update_time+0x8c/0xb0 [btrfs]
  [  199.564277]  file_update_time+0xb8/0xf0
  [  199.564301]  pipe_write+0x8ac/0xab8
  [  199.564326]  vfs_write+0x33c/0x588
  [  199.564349]  ksys_write+0x108/0x150
  [  199.564372]  __s390x_sys_write+0x68/0x88
  [  199.564397]  do_syscall+0x1c6/0x210
  [  199.564424]  __do_syscall+0xc8/0xf0
  [  199.564452]  system_call+0x70/0x98

This is because we update and read last_trans concurrently without any
type of synchronization. This should be generally harmless and in the
worst case it can make us do extra locking (btrfs_record_root_in_trans())
trigger some warnings at ctree.c or do extra work during relocation - this
would probably only happen in case of load or store tearing.

So fix this by always reading and updating the field using READ_ONCE()
and WRITE_ONCE(), this silences KCSAN and prevents load and store tearing.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:52:25 +02:00
Qu Wenruo
32e6216512 btrfs: introduce new "rescue=ignoresuperflags" mount option
This new mount option allows the kernel to skip the super flags check,
it's mostly to allow the kernel to do a rescue mount of an interrupted
checksum conversion.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:30 +02:00
Qu Wenruo
169aaaf2e0 btrfs: introduce new "rescue=ignoremetacsums" mount option
Introduce "rescue=ignoremetacsums" to ignore metadata csums, all the
other metadata sanity checks are still kept as is.

This new mount option is mostly to allow the kernel to mount an
interrupted checksum conversion (at the metadata csum overwrite stage).

And since the main part of metadata sanity checks is inside
tree-checker, we shouldn't lose much safety, and the new mount option is
rescue mount option it requires full read-only mount.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:29 +02:00
Qu Wenruo
cf31b271e0 btrfs: output the unrecognized super block flags as hex
Most of the extra super block flags are beyond 32bits (from
CHANGING_FSID_V2 to CHANGING_*_CSUMS), thus using %llu is not only too
long and pretty hard to read.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:29 +02:00
Mark Harmstone
0102ab54e4 btrfs: fix typo in error message in btrfs_validate_super()
There's a typo in an error message when checking the block group tree
feature, it mentions fres-space-tree instead of free-space-tree. Fix
that.

Signed-off-by: Mark Harmstone <maharmstone@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:29 +02:00
Josef Bacik
133b3da835 btrfs: remove all extra btrfs_check_eb_owner() calls
Currently we have a handful of btrfs_check_eb_owner() calls in various
places and helpers that read extent buffers.  However we call this in
the endio handler for every metadata block, so these extra checks are
unnecessary, simply remove them from everywhere except the endio
handler.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:24 +02:00
David Sterba
2917f74102 btrfs: constify pointer parameters where applicable
We can add const to many parameters, this is for clarity and minor
addition to safety. There are some minor effects, in the assembly
code and .ko measured on release config. This patch does not cover all
possible conversions.

Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:22 +02:00
Anand Jain
53d6c0da0a btrfs: rename err to ret in btrfs_cleanup_fs_roots()
Since err represents the function return value, rename it as ret,
and rename the original ret, which serves as a helper return value,
to found. Also, optimize the code to continue call btrfs_put_root()
for the rest of the root if even after btrfs_orphan_cleanup() returns
error.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:21 +02:00
Filipe Manana
ded980eb3f btrfs: add and use helper to commit the current transaction
We have several places that attach to the current transaction with
btrfs_attach_transaction_barrier() and then commit the transaction if
there is one. Add a helper and use it to deduplicate this pattern.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:20 +02:00
Filipe Manana
cab0d8623f btrfs: avoid create and commit empty transaction when committing super
At btrfs_commit_super(), called in a few contexts such as when unmounting
a filesystem, we use btrfs_join_transaction() to catch any running
transaction and then commit it. This will however create a new and empty
transaction in case there's no running transaction or there's a running
transaction with a state >= TRANS_STATE_UNBLOCKED.

As we just want to be sure that any existing transaction is fully
committed, we can use btrfs_attach_transaction_barrier() instead of
btrfs_join_transaction(), therefore avoiding the creation and commit of
empty transactions, which only waste IO and causes rotation of the
precious backup roots.

Example where we create and commit a pointless empty transaction:

  $ mkfs.btrfs -f /dev/sdj
  $ btrfs inspect-internal dump-super /dev/sdj | grep -e '^generation'
  generation            6

  $ mount /dev/sdj /mnt/sdj
  $ touch /mnt/sdj/foo

  # Commit the currently open transaction. Just 'sync' or wait ~30
  # seconds for the transaction kthread to commit it.
  $ sync

  $ btrfs inspect-internal dump-super /dev/sdj | grep -e '^generation'
  generation            7

  $ umount /mnt/sdj

  $ btrfs inspect-internal dump-super /dev/sdj | grep -e '^generation'
  generation            8

The transaction with id 8 was pointless, an empty transaction that did
not achieve anything.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:19 +02:00
David Sterba
42317ab440 btrfs: simplify range parameters of btrfs_wait_ordered_roots()
The range is specified only in two ways, we can simplify the case for
the whole filesystem range as a NULL block group parameter.

Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:19 +02:00
Anand Jain
83937fb612 btrfs: move btrfs_block_group_root() to block-group.c
The function btrfs_block_group_root() is declared in disk-io.c; however,
all its callers are in block-group.c. Move it to the latter file and
declare it static.

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.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>
2024-07-11 15:33:18 +02:00
Filipe Manana
7a7bc21449 btrfs: remove objectid from struct btrfs_inode on 64 bits platforms
On 64 bits platforms we don't really need to have a dedicated member (the
objectid field) for the inode's number since we store in the VFS inode's
i_ino member, which is an unsigned long and this type is 64 bits wide on
64 bits platforms. We only need that field in case we are on a 32 bits
platform because the unsigned long type is 32 bits wide on such platforms
See commit 33345d0152 ("Btrfs: Always use 64bit inode number") regarding
this 64/32 bits detail.

The objectid field of struct btrfs_inode is also used to store the ID of
a root for directories that are stubs for unreferenced roots. In such
cases the inode is a directory and has the BTRFS_INODE_ROOT_STUB runtime
flag set.

So in order to reduce the size of btrfs_inode structure on 64 bits
platforms we can remove the objectid member and use the VFS inode's i_ino
member instead whenever we need to get the inode number. In case the inode
is a root stub (BTRFS_INODE_ROOT_STUB set) we can use the member
last_reflink_trans to store the ID of the unreferenced root, since such
inode is a directory and reflinks can't be done against directories.

So remove the objectid fields for 64 bits platforms and alias the
last_reflink_trans field with a name of ref_root_id in a union.
On a release kernel config, this reduces the size of struct btrfs_inode
from 1040 bytes down to 1032 bytes.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:17 +02:00
Filipe Manana
068fc8f914 btrfs: remove location key from struct btrfs_inode
Currently struct btrfs_inode has a key member, named "location", that is
either:

1) The key of the inode's item. In this case the objectid is the number
   of the inode;

2) A key stored in a dir entry with a type of BTRFS_ROOT_ITEM_KEY, for
   the case where we have a root that is a snapshot of a subvolume that
   points to other subvolumes. In this case the objectid is the ID of
   a subvolume inside the snapshotted parent subvolume.

The key is only used to lookup the inode item for the first case, while
for the second it's never used since it corresponds to directory stubs
created with new_simple_dir() and which are marked as dummy, so there's
no actual inode item to ever update. In the second case we only check
the key type at btrfs_ino() for 32 bits platforms and its objectid is
only needed for unlink.

Instead of using a key we can do fine with just the objectid, since we
can generate the key whenever we need it having only the objectid, as
in all use cases the type is always BTRFS_INODE_ITEM_KEY and the offset
is always 0.

So use only an objectid instead of a full key. This reduces the size of
struct btrfs_inode from 1048 bytes down to 1040 bytes on a release kernel.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:17 +02:00
Filipe Manana
e2844cce75 btrfs: remove inode_lock from struct btrfs_root and use xarray locks
Currently we use the spinlock inode_lock from struct btrfs_root to
serialize access to two different data structures:

1) The delayed inodes xarray (struct btrfs_root::delayed_nodes);
2) The inodes xarray (struct btrfs_root::inodes).

Instead of using our own lock, we can use the spinlock that is part of the
xarray implementation, by using the xa_lock() and xa_unlock() APIs and
using the xarray APIs with the double underscore prefix that don't take
the xarray locks and assume the caller is using xa_lock() and xa_unlock().

So remove the spinlock inode_lock from struct btrfs_root and use the
corresponding xarray locks. This brings 2 benefits:

1) We reduce the size of struct btrfs_root, from 1336 bytes down to
   1328 bytes on a 64 bits release kernel config;

2) We reduce lock contention by not using anymore the same lock for
   changing two different and unrelated xarrays.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:17 +02:00
Filipe Manana
310b2f5d5a btrfs: use an xarray to track open inodes in a root
Currently we use a red black tree (rb-tree) to track the currently open
inodes of a root (in struct btrfs_root::inode_tree). This however is not
very efficient when the number of inodes is large since rb-trees are
binary trees. For example for 100K open inodes, the tree has a depth of
17. Besides that, inserting into the tree requires navigating through it
and pulling useless cache lines in the process since the red black tree
nodes are embedded within the btrfs inode - on the other hand, by being
embedded, it requires no extra memory allocations.

We can improve this by using an xarray instead, which is efficient when
indices are densely clustered (such as inode numbers), is more cache
friendly and behaves like a resizable array, with a much better search
and insertion complexity than a red black tree. This only has one small
disadvantage which is that insertion will sometimes require allocating
memory for the xarray - which may fail (not that often since it uses a
kmem_cache) - but on the other hand we can reduce the btrfs inode
structure size by 24 bytes (from 1080 down to 1056 bytes) after removing
the embedded red black tree node, which after the next patches will allow
to reduce the size of the structure to 1024 bytes, meaning we will be able
to store 4 inodes per 4K page instead of 3 inodes.

This change does a straightforward change to use an xarray, and results
in a transaction abort if we can't allocate memory for the xarray when
creating an inode - but the next patch changes things so that we don't
need to abort.

Running the following fs_mark test showed some improvements:

    $ cat test.sh
    #!/bin/bash

    DEV=/dev/nullb0
    MNT=/mnt/nullb0
    MOUNT_OPTIONS="-o ssd"
    FILES=100000
    THREADS=$(nproc --all)

    echo "performance" | \
        tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

    mkfs.btrfs -f $DEV
    mount $MOUNT_OPTIONS $DEV $MNT

    OPTS="-S 0 -L 5 -n $FILES -s 0 -t $THREADS -k"
    for ((i = 1; i <= $THREADS; i++)); do
        OPTS="$OPTS -d $MNT/d$i"
    done

    fs_mark $OPTS

    umount $MNT

Before this patch:

    FSUse%        Count         Size    Files/sec     App Overhead
        10      1200000            0      92081.6         12505547
        16      2400000            0     138222.6         13067072
        23      3600000            0     148833.1         13290336
        43      4800000            0      97864.7         13931248
        53      6000000            0      85597.3         14384313

After this patch:

    FSUse%        Count         Size    Files/sec     App Overhead
        10      1200000            0      93225.1         12571078
        16      2400000            0     146720.3         12805007
        23      3600000            0     160626.4         13073835
        46      4800000            0     116286.2         13802927
        53      6000000            0      90087.9         14754892

The test was run with a release kernel config (Debian's default config).

Also capturing the insertion times into the rb tree and into the xarray,
that is measuring the duration of the old function inode_tree_add() and
the duration of the new btrfs_add_inode_to_root() function, gave the
following results (in nanoseconds):

Before this patch, inode_tree_add() execution times:

   Count: 5000000
   Range:  0.000 - 5536887.000; Mean: 775.674; Median: 729.000; Stddev: 4820.961
   Percentiles:  90th: 1015.000; 95th: 1139.000; 99th: 1397.000
         0.000 -       7.816:      40 |
         7.816 -      37.858:     209 |
        37.858 -     170.278:    6059 |
       170.278 -     753.961: 2754890 #####################################################
       753.961 -    3326.728: 2232312 ###########################################
      3326.728 -   14667.018:    4366 |
     14667.018 -   64652.943:     852 |
     64652.943 -  284981.761:     550 |
    284981.761 - 1256150.914:     221 |
   1256150.914 - 5536887.000:       7 |

After this patch, btrfs_add_inode_to_root() execution times:

   Count: 5000000
   Range:  0.000 - 2900652.000; Mean: 272.148; Median: 241.000; Stddev: 2873.369
   Percentiles:  90th: 342.000; 95th: 432.000; 99th: 572.000
        0.000 -       7.264:     104 |
        7.264 -      33.145:     352 |
       33.145 -     140.081:  109606 #
      140.081 -     581.930: 4840090 #####################################################
      581.930 -    2407.590:   43532 |
     2407.590 -    9950.979:    2245 |
     9950.979 -   41119.278:     514 |
    41119.278 -  169902.616:     155 |
   169902.616 -  702018.539:      47 |
   702018.539 - 2900652.000:       9 |

Average, percentiles, standard deviation, etc, are all much better.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11 15:33:17 +02:00
Linus Torvalds
07978330e6 for-6.10-rc2-tag
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Merge tag 'for-6.10-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix handling of folio private changes.

   The private value holds pointer to our extent buffer structure
   representing a metadata range. Release and create of the range was
   not properly synchronized when updating the private bit which ended
   up in double folio_put, leading to all sorts of breakage

 - fix a crash, reported as duplicate key in metadata, but caused by a
   race of fsync and size extending write. Requires prealloc target
   range + fsync and other conditions (log tree state, timing)

 - fix leak of qgroup extent records after transaction abort

* tag 'for-6.10-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: protect folio::private when attaching extent buffer folios
  btrfs: fix leak of qgroup extent records after transaction abort
  btrfs: fix crash on racing fsync and size-extending write into prealloc
2024-06-07 15:13:12 -07:00
Filipe Manana
fb33eb2ef0 btrfs: fix leak of qgroup extent records after transaction abort
Qgroup extent records are created when delayed ref heads are created and
then released after accounting extents at btrfs_qgroup_account_extents(),
called during the transaction commit path.

If a transaction is aborted we free the qgroup records by calling
btrfs_qgroup_destroy_extent_records() at btrfs_destroy_delayed_refs(),
unless we don't have delayed references. We are incorrectly assuming
that no delayed references means we don't have qgroup extents records.

We can currently have no delayed references because we ran them all
during a transaction commit and the transaction was aborted after that
due to some error in the commit path.

So fix this by ensuring we btrfs_qgroup_destroy_extent_records() at
btrfs_destroy_delayed_refs() even if we don't have any delayed references.

Reported-by: syzbot+0fecc032fa134afd49df@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/0000000000004e7f980619f91835@google.com/
Fixes: 81f7eb00ff ("btrfs: destroy qgroup extent records on transaction abort")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-06-05 18:06:54 +02:00
Linus Torvalds
38da32ee70 bd_inode series
Replacement of bdev->bd_inode with sane(r) set of primitives.
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Merge tag 'pull-bd_inode-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull bdev bd_inode updates from Al Viro:
 "Replacement of bdev->bd_inode with sane(r) set of primitives by me and
  Yu Kuai"

* tag 'pull-bd_inode-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  RIP ->bd_inode
  dasd_format(): killing the last remaining user of ->bd_inode
  nilfs_attach_log_writer(): use ->bd_mapping->host instead of ->bd_inode
  block/bdev.c: use the knowledge of inode/bdev coallocation
  gfs2: more obvious initializations of mapping->host
  fs/buffer.c: massage the remaining users of ->bd_inode to ->bd_mapping
  blk_ioctl_{discard,zeroout}(): we only want ->bd_inode->i_mapping here...
  grow_dev_folio(): we only want ->bd_inode->i_mapping there
  use ->bd_mapping instead of ->bd_inode->i_mapping
  block_device: add a pointer to struct address_space (page cache of bdev)
  missing helpers: bdev_unhash(), bdev_drop()
  block: move two helpers into bdev.c
  block2mtd: prevent direct access of bd_inode
  dm-vdo: use bdev_nr_bytes(bdev) instead of i_size_read(bdev->bd_inode)
  blkdev_write_iter(): saner way to get inode and bdev
  bcachefs: remove dead function bdev_sectors()
  ext4: remove block_device_ejected()
  erofs_buf: store address_space instead of inode
  erofs: switch erofs_bread() to passing offset instead of block number
2024-05-21 09:51:42 -07:00
Matthew Wilcox (Oracle)
bc00965dbf btrfs: count super block write errors in device instead of tracking folio error state
Currently the error status of super block write is tracked in page/folio
status bit Error. For that we need to keep the reference for the whole
duration of write and wait.

Count the number of superblock writeback errors in the btrfs_device.
That means we don't need the folio to stay around until it's waited for,
and can avoid the extra call to folio_get/put.

Also remove a mention of PageError in a comment as it's the last mention
of the page Error state.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:11 +02:00
Matthew Wilcox (Oracle)
617fb10ea8 btrfs: use the folio iterator in btrfs_end_super_write()
Iterate over folios instead of bvecs.  Switch the order of unlock and put
to be the usual order; we know this folio can't be put until it's been
waited for, but that's fragile.  Remove the calls to ClearPageUptodate /
SetPageUptodate -- if PAGE_SIZE is larger than BTRFS_SUPER_INFO_SIZE,
we'd be marking the entire folio uptodate without having actually
initialised all the bytes in the page.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:10 +02:00
Matthew Wilcox (Oracle)
f93ee0df51 btrfs: convert super block writes to folio in write_dev_supers()
This is a direct conversion from pages to folios, assuming single page
folio. Also removes some calls to obsolete APIs and some hidden calls to
compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:10 +02:00
Matthew Wilcox (Oracle)
c94b7349b8 btrfs: convert super block writes to folio in wait_dev_supers()
This is a direct conversion from pages to folios, assuming single page
folio.  Also removes a few calls to compound_head() and calls to
obsolete APIs.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:10 +02:00
David Sterba
fef998d1a0 btrfs: use btrfs_is_testing() everywhere
There are open coded tests of BTRFS_FS_STATE_DUMMY_FS_INFO and we have a
wrapper for that that's a compile-time constant when self-tests are not
built in. As this is only for development we can save some bytes and
conditions on release configs by using the helper in the remaining
cases.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:07 +02:00
Filipe Manana
905a95f3dd btrfs: initialize delayed inodes xarray without GFP_ATOMIC
There's no need to initialize the delayed inodes xarray with a GFP_ATOMIC
flag because that actually does nothing on the xarray operations. That was
needed for radix trees, but for xarrays the allocation flags are passed as
the last argument to xa_store() (which we are using correctly).

So initialize the delayed inodes xarray with a simple xa_init().

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:07 +02:00
Filipe Manana
f1d97e7691 btrfs: add a global per cpu counter to track number of used extent maps
Add a per cpu counter that tracks the total number of extent maps that are
in extent trees of inodes that belong to fs trees. This is going to be
used in an upcoming change that adds a shrinker for extent maps. Only
extent maps for fs trees are considered, because for special trees such as
the data relocation tree we don't want to evict their extent maps which
are critical for the relocation to work, and since those are limited, it's
not a concern to have them in memory during the relocation of a block
group. Another case are extent maps for free space cache inodes, which
must always remain in memory, but those are limited (there's only one per
free space cache inode, which means one per block group).

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:06 +02:00
Josef Bacik
e094f48040 btrfs: change root->root_key.objectid to btrfs_root_id()
A comment from Filipe on one of my previous cleanups brought my
attention to a new helper we have for getting the root id of a root,
which makes it easier to read in the code.

The changes where made with the following Coccinelle semantic patch:

// <smpl>
@@
expression E,E1;
@@
(
 E->root_key.objectid = E1
|
- E->root_key.objectid
+ btrfs_root_id(E)
)
// </smpl>

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor style fixups ]
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:06 +02:00
Filipe Manana
606a1c5de1 btrfs: remove list_empty() check at warn_about_uncommitted_trans()
At warn_about_uncommitted_trans(), there's no need to check if the list
is empty and return, because list_for_each_entry_safe() is safe to call
for an empty list, it simply does nothing. So remove the check.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:03 +02:00
Boris Burkov
5f2fb819f6 btrfs: free PERTRANS at the end of cleanup_transaction()
Some of the operations after the free might convert more PERTRANS
metadata. Do the freeing as late as possible to eliminate a source of
leaked PERTRANS metadata.

This helps with the pass rate of generic/269 and generic/475.

Reviewed-by: Qu Wenruo <qwu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07 21:31:02 +02:00
Al Viro
224941e837 use ->bd_mapping instead of ->bd_inode->i_mapping
Just the low-hanging fruit...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/r/20240411145346.2516848-2-viro@zeniv.linux.org.uk
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-05-03 02:36:51 -04:00
David Sterba
5a8a57f9a4 btrfs: merge btrfs_del_delalloc_inode() helpers
The helpers btrfs_del_delalloc_inode() and __btrfs_del_delalloc_inode()
don't follow the pattern when the "__" helper does a special case and
are in fact reversed regarding the naming. We can merge them into one as
there's only one place that needs to be open coded.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:54 +01:00
Filipe Manana
f5169f12d7 btrfs: stop passing root argument to __btrfs_del_delalloc_inode()
There's no need to pass a root argument to __btrfs_del_delalloc_inode()
and btrfs_del_delalloc_inode(), we can just pass the inode since the root
is always the root associated to that inode. Some remove the root argument
from these functions.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:49 +01:00
David Sterba
41044b41ad btrfs: add helper to get fs_info from struct inode pointer
Add a convenience helper to get a fs_info from a VFS inode pointer
instead of open coding the chain or using btrfs_sb() that in some cases
does one more pointer hop.  This is implemented as a macro (still with
type checking) so we don't need full definitions of struct btrfs_inode,
btrfs_root or btrfs_fs_info.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:49 +01:00
David Sterba
b33d2e535f btrfs: add helpers to get fs_info from page/folio pointers
Add convenience helpers to get a fs_info from a page or folio pointer
instead of open coding the chain or using btrfs_sb() that in some cases
does one more pointer hop.  This is implemented as a macro (still with
type checking) so we don't need full definitions of struct page, folio,
btrfs_root and btrfs_fs_info. The latter can't be static inlines as this
would create loop between ctree.h <-> fs.h, or the headers would have to
be restructured.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:49 +01:00
David Sterba
c8293894af btrfs: add helpers to get inode from page/folio pointers
Add convenience helpers to get a struct btrfs_inode from a page or folio
pointer instead of open coding the chain or intermediate BTRFS_I. This
is implemented as a macro (still with type checking) so we don't need
full definitions of struct page or address_space.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:49 +01:00
David Sterba
2467d0fead btrfs: change BUG_ON to assertion in btrfs_read_roots()
There's one caller of btrfs_read_roots() and that already uses the
tree_root pointer, it's pointless to BUG_ON on it. As it's an assumption
of the initialization helpers make it an assert instead.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:48 +01:00
David Sterba
a67242907b btrfs: handle invalid root reference found in btrfs_init_root_free_objectid()
The btrfs_init_root_free_objectid() looks up a root by a key, allowing
to do an inexact search when key->offset is -1.  It's never expected to
find such item, as it would break the allowed range of a root id.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:47 +01:00
David Sterba
2b712e3bb2 btrfs: remove unused included headers
With help of neovim, LSP and clangd we can identify header files that
are not actually needed to be included in the .c files. This is focused
only on removal (with minor fixups), further cleanups are possible but
will require doing the header files properly with forward declarations,
minimized includes and include-what-you-use care.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:46 +01:00
David Sterba
4e00422ee6 btrfs: replace sb::s_blocksize by fs_info::sectorsize
The block size stored in the super block is used by subsystems outside
of btrfs and it's a copy of fs_info::sectorsize. Unify that to always
use our sectorsize, with the exception of mount where we first need to
use fixed values (4K) until we read the super block and can set the
sectorsize.

Replace all uses, in most cases it's fewer pointer indirections.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:46 +01:00
Josef Bacik
8fd2b12e6a btrfs: WARN_ON_ONCE() in our leak detection code
fstests looks for WARN_ON's in dmesg.  Add WARN_ON_ONCE() to our leak
detection code (enabled only in debug builds) so that fstests will fail
if these things trip at all.  This will allow us to easily catch
problems with our reference counting that may otherwise go unnoticed.

Reviewed-by: Neal Gompa <neal@gompa.dev>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:45 +01:00
Qu Wenruo
84cda1a608 btrfs: cache folio size and shift in extent_buffer
After the conversion to folio interfaces (but without the patch to
enable larger folio allocation), there is an LTP report about observable
performance drop on metadata heavy operations.

https://lore.kernel.org/linux-btrfs/202312221750.571925bd-oliver.sang@intel.com/

This drop is caused by the extra code of calculating the
folio_size()/folio_shift(), instead of the old hard coded
PAGE_SIZE/PAGE_SHIFT.

To slightly reduce the overhead, just cache both folio_size and
folio_shift in extent_buffer.

The two new members (u32 folio_size and u8 folio_shift) are stored
inside the holes of extent_buffer. folio_size is shared with len, which
is reduced to u32. The size of eb does not change.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04 16:24:45 +01:00
Filipe Manana
e2b54eaf28 btrfs: fix double free of anonymous device after snapshot creation failure
When creating a snapshot we may do a double free of an anonymous device
in case there's an error committing the transaction. The second free may
result in freeing an anonymous device number that was allocated by some
other subsystem in the kernel or another btrfs filesystem.

The steps that lead to this:

1) At ioctl.c:create_snapshot() we allocate an anonymous device number
   and assign it to pending_snapshot->anon_dev;

2) Then we call btrfs_commit_transaction() and end up at
   transaction.c:create_pending_snapshot();

3) There we call btrfs_get_new_fs_root() and pass it the anonymous device
   number stored in pending_snapshot->anon_dev;

4) btrfs_get_new_fs_root() frees that anonymous device number because
   btrfs_lookup_fs_root() returned a root - someone else did a lookup
   of the new root already, which could some task doing backref walking;

5) After that some error happens in the transaction commit path, and at
   ioctl.c:create_snapshot() we jump to the 'fail' label, and after
   that we free again the same anonymous device number, which in the
   meanwhile may have been reallocated somewhere else, because
   pending_snapshot->anon_dev still has the same value as in step 1.

Recently syzbot ran into this and reported the following trace:

  ------------[ cut here ]------------
  ida_free called for id=51 which is not allocated.
  WARNING: CPU: 1 PID: 31038 at lib/idr.c:525 ida_free+0x370/0x420 lib/idr.c:525
  Modules linked in:
  CPU: 1 PID: 31038 Comm: syz-executor.2 Not tainted 6.8.0-rc4-syzkaller-00410-gc02197fc9076 #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
  RIP: 0010:ida_free+0x370/0x420 lib/idr.c:525
  Code: 10 42 80 3c 28 (...)
  RSP: 0018:ffffc90015a67300 EFLAGS: 00010246
  RAX: be5130472f5dd000 RBX: 0000000000000033 RCX: 0000000000040000
  RDX: ffffc90009a7a000 RSI: 000000000003ffff RDI: 0000000000040000
  RBP: ffffc90015a673f0 R08: ffffffff81577992 R09: 1ffff92002b4cdb4
  R10: dffffc0000000000 R11: fffff52002b4cdb5 R12: 0000000000000246
  R13: dffffc0000000000 R14: ffffffff8e256b80 R15: 0000000000000246
  FS:  00007fca3f4b46c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f167a17b978 CR3: 000000001ed26000 CR4: 0000000000350ef0
  Call Trace:
   <TASK>
   btrfs_get_root_ref+0xa48/0xaf0 fs/btrfs/disk-io.c:1346
   create_pending_snapshot+0xff2/0x2bc0 fs/btrfs/transaction.c:1837
   create_pending_snapshots+0x195/0x1d0 fs/btrfs/transaction.c:1931
   btrfs_commit_transaction+0xf1c/0x3740 fs/btrfs/transaction.c:2404
   create_snapshot+0x507/0x880 fs/btrfs/ioctl.c:848
   btrfs_mksubvol+0x5d0/0x750 fs/btrfs/ioctl.c:998
   btrfs_mksnapshot+0xb5/0xf0 fs/btrfs/ioctl.c:1044
   __btrfs_ioctl_snap_create+0x387/0x4b0 fs/btrfs/ioctl.c:1306
   btrfs_ioctl_snap_create_v2+0x1ca/0x400 fs/btrfs/ioctl.c:1393
   btrfs_ioctl+0xa74/0xd40
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:871 [inline]
   __se_sys_ioctl+0xfe/0x170 fs/ioctl.c:857
   do_syscall_64+0xfb/0x240
   entry_SYSCALL_64_after_hwframe+0x6f/0x77
  RIP: 0033:0x7fca3e67dda9
  Code: 28 00 00 00 (...)
  RSP: 002b:00007fca3f4b40c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  RAX: ffffffffffffffda RBX: 00007fca3e7abf80 RCX: 00007fca3e67dda9
  RDX: 00000000200005c0 RSI: 0000000050009417 RDI: 0000000000000003
  RBP: 00007fca3e6ca47a R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
  R13: 000000000000000b R14: 00007fca3e7abf80 R15: 00007fff6bf95658
   </TASK>

Where we get an explicit message where we attempt to free an anonymous
device number that is not currently allocated. It happens in a different
code path from the example below, at btrfs_get_root_ref(), so this change
may not fix the case triggered by syzbot.

To fix at least the code path from the example above, change
btrfs_get_root_ref() and its callers to receive a dev_t pointer argument
for the anonymous device number, so that in case it frees the number, it
also resets it to 0, so that up in the call chain we don't attempt to do
the double free.

CC: stable@vger.kernel.org # 5.10+
Link: https://lore.kernel.org/linux-btrfs/000000000000f673a1061202f630@google.com/
Fixes: e03ee2fe87 ("btrfs: do not ASSERT() if the newly created subvolume already got read")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-02-29 22:34:11 +01:00
Qu Wenruo
e03ee2fe87 btrfs: do not ASSERT() if the newly created subvolume already got read
[BUG]
There is a syzbot crash, triggered by the ASSERT() during subvolume
creation:

 assertion failed: !anon_dev, in fs/btrfs/disk-io.c:1319
 ------------[ cut here ]------------
 kernel BUG at fs/btrfs/disk-io.c:1319!
 invalid opcode: 0000 [#1] PREEMPT SMP KASAN
 RIP: 0010:btrfs_get_root_ref.part.0+0x9aa/0xa60
  <TASK>
  btrfs_get_new_fs_root+0xd3/0xf0
  create_subvol+0xd02/0x1650
  btrfs_mksubvol+0xe95/0x12b0
  __btrfs_ioctl_snap_create+0x2f9/0x4f0
  btrfs_ioctl_snap_create+0x16b/0x200
  btrfs_ioctl+0x35f0/0x5cf0
  __x64_sys_ioctl+0x19d/0x210
  do_syscall_64+0x3f/0xe0
  entry_SYSCALL_64_after_hwframe+0x63/0x6b
 ---[ end trace 0000000000000000 ]---

[CAUSE]
During create_subvol(), after inserting root item for the newly created
subvolume, we would trigger btrfs_get_new_fs_root() to get the
btrfs_root of that subvolume.

The idea here is, we have preallocated an anonymous device number for
the subvolume, thus we can assign it to the new subvolume.

But there is really nothing preventing things like backref walk to read
the new subvolume.
If that happens before we call btrfs_get_new_fs_root(), the subvolume
would be read out, with a new anonymous device number assigned already.

In that case, we would trigger ASSERT(), as we really expect no one to
read out that subvolume (which is not yet accessible from the fs).
But things like backref walk is still possible to trigger the read on
the subvolume.

Thus our assumption on the ASSERT() is not correct in the first place.

[FIX]
Fix it by removing the ASSERT(), and just free the @anon_dev, reset it
to 0, and continue.

If the subvolume tree is read out by something else, it should have
already get a new anon_dev assigned thus we only need to free the
preallocated one.

Reported-by: Chenyuan Yang <chenyuan0y@gmail.com>
Fixes: 2dfb1e43f5 ("btrfs: preallocate anon block device at first phase of snapshot creation")
CC: stable@vger.kernel.org # 5.15+
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>
2024-01-31 08:42:53 +01:00
Qu Wenruo
96c36eaa77 btrfs: migrate btrfs_repair_io_failure() to folio interfaces
[BUG]
Test case btrfs/124 failed if larger metadata folio is enabled, the
dying message looks like this:

 BTRFS error (device dm-2): bad tree block start, mirror 2 want 31686656 have 0
 BTRFS info (device dm-2): read error corrected: ino 0 off 31686656 (dev /dev/mapper/test-scratch2 sector 20928)
 BUG: kernel NULL pointer dereference, address: 0000000000000020
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 CPU: 6 PID: 350881 Comm: btrfs Tainted: G           OE      6.7.0-rc3-custom+ #128
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 2/2/2022
 RIP: 0010:btrfs_read_extent_buffer+0x106/0x180 [btrfs]
 PKRU: 55555554
 Call Trace:
  <TASK>
  read_tree_block+0x33/0xb0 [btrfs]
  read_block_for_search+0x23e/0x340 [btrfs]
  btrfs_search_slot+0x2f9/0xe60 [btrfs]
  btrfs_lookup_csum+0x75/0x160 [btrfs]
  btrfs_lookup_bio_sums+0x21a/0x560 [btrfs]
  btrfs_submit_chunk+0x152/0x680 [btrfs]
  btrfs_submit_bio+0x1c/0x50 [btrfs]
  submit_one_bio+0x40/0x80 [btrfs]
  submit_extent_page+0x158/0x390 [btrfs]
  btrfs_do_readpage+0x330/0x740 [btrfs]
  extent_readahead+0x38d/0x6c0 [btrfs]
  read_pages+0x94/0x2c0
  page_cache_ra_unbounded+0x12d/0x190
  relocate_file_extent_cluster+0x7c1/0x9d0 [btrfs]
  relocate_block_group+0x2d3/0x560 [btrfs]
  btrfs_relocate_block_group+0x2c7/0x4b0 [btrfs]
  btrfs_relocate_chunk+0x4c/0x1a0 [btrfs]
  btrfs_balance+0x925/0x13c0 [btrfs]
  btrfs_ioctl+0x19f1/0x25d0 [btrfs]
  __x64_sys_ioctl+0x90/0xd0
  do_syscall_64+0x3f/0xf0
  entry_SYSCALL_64_after_hwframe+0x6e/0x76

[CAUSE]
The dying line is at btrfs_repair_io_failure() call inside
btrfs_repair_eb_io_failure().

The function is still relying on the extent buffer using page sized
folios.
When the extent buffer is using larger folio, we go into the 2nd slot of
folios[], and triggered the NULL pointer dereference.

[FIX]
Migrate btrfs_repair_io_failure() to folio interfaces.

So that when we hit a larger folio, we just submit the whole folio in
one go.

This also affects data repair path through btrfs_end_repair_bio(),
thankfully data is still fully page based, we can just add an
ASSERT(), and use page_folio() to convert the page to folio.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 23:03:58 +01:00
Qu Wenruo
55151ea9ec btrfs: migrate subpage code to folio interfaces
Although subpage itself is conflicting with higher folio, since subpage
(sectorsize < PAGE_SIZE and nodesize < PAGE_SIZE) means we will never
need higher order folio, there is a hidden pitfall:

- btrfs_page_*() helpers

Those helpers are an abstraction to handle both subpage and non-subpage
cases, which means we're going to pass pages pointers to those helpers.

And since those helpers are shared between data and metadata paths, it's
unavoidable to let them to handle folios, including higher order
folios).

Meanwhile for true subpage case, we should only have a single page
backed folios anyway, thus add a new ASSERT() for btrfs_subpage_assert()
to ensure that.

Also since those helpers are shared between both data and metadata, add
some extra ASSERT()s for data path to make sure we only get single page
backed folio for now.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 23:03:58 +01:00
Qu Wenruo
8d99361835 btrfs: migrate get_eb_page_index() and get_eb_offset_in_page() to folios
These two functions are still using the old page based code, which is
not going to handle larger folios at all.

The migration itself is going to involve the following changes:

- PAGE_SIZE -> folio_size()
- PAGE_SHIFT -> folio_shift()
- get_eb_page_index() -> get_eb_folio_index()
- get_eb_offset_in_page() -> get_eb_offset_in_folio()

And since we're going to support larger folios, although above straight
conversion is good enough, this patch would add extra comments in the
involved functions to explain why the same single line code can now
cover 3 cases:

- folio_size == PAGE_SIZE, sectorsize == PAGE_SIZE, nodesize >= PAGE_SIZE
  The common, non-subpage case with per-page folio.

- folio_size > PAGE_SIZE, sectorsize == PAGE_SIZE, nodesize >= PAGE_SIZE
  The incoming larger folio, non-subpage case.

- folio_size == PAGE_SIZE, sectorsize < PAGE_SIZE, nodesize < PAGE_SIZE
  The existing subpage case, we won't larger folio anyway.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 23:03:58 +01:00
Qu Wenruo
13df3775ef btrfs: cleanup metadata page pointer usage
Although we have migrated extent_buffer::pages[] to folios[], we're
still mostly using the folio_page() help to grab the page.

This patch would do the following cleanups for metadata:

- Introduce num_extent_folios() helper
  This is to replace most num_extent_pages() callers.

- Use num_extent_folios() to iterate future large folios
  This allows us to use things like
  bio_add_folio()/bio_add_folio_nofail(), and only set the needed flags
  for the folio (aka the leading/tailing page), which reduces the loop
  iteration to 1 for large folios.

- Change metadata related functions to use folio pointers
  Including their function name, involving:
  * attach_extent_buffer_page()
  * detach_extent_buffer_page()
  * page_range_has_eb()
  * btrfs_release_extent_buffer_pages()
  * btree_clear_page_dirty()
  * btrfs_page_inc_eb_refs()
  * btrfs_page_dec_eb_refs()

- Change btrfs_is_subpage() to accept an address_space pointer
  This is to allow both page->mapping and folio->mapping to be utilized.
  As data is still using the old per-page code, and may keep so for a
  while.

- Special corner case place holder for future order mismatches between
  extent buffer and inode filemap
  For now it's  just a block of comments and a dead ASSERT(), no real
  handling yet.

The subpage code would still go page, just because subpage and large
folio are conflicting conditions, thus we don't need to bother subpage
with higher order folios at all. Just folio_page(folio, 0) would be
enough.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor styling tweaks ]
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 23:01:04 +01:00
Qu Wenruo
082d5bb9b3 btrfs: migrate extent_buffer::pages[] to folio
For now extent_buffer::pages[] are still only accepting single page
pointer, thus we can migrate to folios pretty easily.

As for single page, page and folio are 1:1 mapped, including their page
flags.

This patch would just do the conversion from struct page to struct
folio, providing the first step to higher order folio in the future.

This conversion is pretty simple:

- extent_buffer::pages[] -> extent_buffer::folios[]

- page_address(eb->pages[i]) -> folio_address(eb->pages[i])

- eb->pages[i] -> folio_page(eb->folios[i], 0)

There would be more specific cleanups preparing for the incoming higher
order folio support.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 23:01:04 +01:00
David Sterba
6140ba8a0a btrfs: switch btrfs_root::delayed_nodes_tree to xarray from radix-tree
The radix-tree has been superseded by the xarray
(https://lwn.net/Articles/745073), this patch converts the
btrfs_root::delayed_nodes, the APIs are used in a simple way.

First idea is to do xa_insert() but this would require GFP_ATOMIC
allocation which we want to avoid if possible. The preload mechanism of
radix-tree can be emulated within the xarray API.

- xa_reserve() with GFP_NOFS outside of the lock, the reserved entry
  is inserted atomically at most once

- xa_store() under a lock, in case something races in we can detect that
  and xa_load() returns a valid pointer

All uses of xa_load() must check for a valid pointer in case they manage
to get between the xa_reserve() and xa_store(), this is handled in
btrfs_get_delayed_node().

Otherwise the functionality is equivalent, xarray implements the
radix-tree and there should be no performance difference.

The patch continues the efforts started in 253bf57555 ("btrfs: turn
delayed_nodes_tree into an XArray") and fixes the problems with locking
and GFP flags 088aea3b97 ("Revert "btrfs: turn delayed_nodes_tree
into an XArray"").

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 23:01:03 +01:00
Josef Bacik
9fb3b1a7fe btrfs: set clear_cache if we use usebackuproot
We're currently setting this when we try to load the roots and we see
that usebackuproot is set.  Instead set this at mount option parsing
time.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:05 +01:00
Josef Bacik
83e3a40a69 btrfs: move one shot mount option clearing to super.c
There's no reason this has to happen in open_ctree, and in fact in the
old mount API we had to call this from remount.  Move this to super.c,
unexport it, and call it from both mount and reconfigure.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:04 +01:00
Josef Bacik
41d46b290e btrfs: move the device specific mount options to super.c
We add these mount options based on the fs_devices settings, which can
be set once we've opened the fs_devices.  Move these into their own
helper and call it from get_tree_super.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:04 +01:00
Josef Bacik
ad21f15b0f btrfs: switch to the new mount API
Now that we have all of the parts in place to use the new mount API,
switch our fs_type to use the new callbacks.

There are a few things that have to be done at the same time because of
the order of operations changes that come along with the new mount API.
These must be done in the same patch otherwise things will go wrong.

1. Export and use btrfs_check_options in open_ctree().  This is because
   the options are done ahead of time, and we need to check them once we
   have the feature flags loaded.

2. Update the free space cache settings.  Since we're coming in with the
   options already set we need to make sure we don't undo what the user
   has asked for.

3. Set our sb_flags at init_fs_context time, the fs_context stuff is
   trying to manage the sb_flagss itself, so move that into
   init_fs_context and out of the fill super part.

Additionally I've marked the unused functions with __maybe_unused and
will remove them in a future patch.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:04 +01:00
Josef Bacik
2496bff6e5 btrfs: add a NOSPACECACHE mount option flag
With the old mount API we'd pre-populate the mount options with the
space cache settings of the file system, and then the user toggled them
on or off with the mount options.  When we switch to the new mount API
the mount options will be set before we get into opening the file
system, so we need a flag to indicate that the user explicitly asked for
-o nospace_cache so we can make the appropriate changes after the fact.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:04 +01:00
Josef Bacik
272efa308f btrfs: do not allow free space tree rebuild on extent tree v2
We currently don't allow these options to be set if we're extent tree v2
via the mount option parsing.  However when we switch to the new mount
API we'll no longer have the super block loaded, so won't be able to
make this distinction at mount option parsing time.  Address this by
checking for extent tree v2 at the point where we make the decision to
rebuild the free space tree.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:03 +01:00
Josef Bacik
a6a8f22a4a btrfs: move space cache settings into open_ctree
Currently we pre-load the space cache settings in btrfs_parse_options,
however when we switch to the new mount API the mount option parsing
will happen before we have the super block loaded.  Add a helper to set
the appropriate options based on the fs settings, this will allow us to
have consistent free space cache settings.

This also folds in the space cache related decisions we make for subpage
sectorsize support, so all of this is done in one place.

Since this was being called by parse options it looks like we're
changing the behavior of remount, but in fact we aren't.  The
pre-loading of the free space cache settings is done because we want to
handle the case of users not using any space_cache options, we'll derive
the appropriate mount option based on the on disk state.  On remount
this wouldn't reset anything as we'll have cleared the v1 cache
generation if we mounted -o nospace_cache.  Similarly it's impossible to
turn off the free space tree without specifically saying -o
nospace_cache,clear_cache, which will delete the free space tree and
clear the compat_ro option.  Again in this case calling this code in
remount wouldn't result in any change.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:03 +01:00
Josef Bacik
6207c9e3c2 btrfs: set default compress type at btrfs_init_fs_info time
With the new mount API we'll be setting our compression well before we
call open_ctree.  We don't want to overwrite our settings, so set the
default in btrfs_init_fs_info instead of open_ctree.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:03 +01:00
Qu Wenruo
397239ed6a btrfs: allow extent buffer helpers to skip cross-page handling
Currently btrfs extent buffer helpers are doing all the cross-page
handling, as there is no guarantee that all those eb pages are
contiguous.

However on systems with enough memory, there is a very high chance the
page cache for btree_inode are allocated with physically contiguous
pages.

In that case, we can skip all the complex cross-page handling, thus
speeding up the code.

This patch adds a new member, extent_buffer::addr, which is only set to
non-NULL if all the extent buffer pages are physically contiguous.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:03 +01:00
Johannes Thumshirn
aa6313e6ff btrfs: zoned: don't clear dirty flag of extent buffer
One a zoned filesystem, never clear the dirty flag of an extent buffer,
but instead mark it as zeroout.

On writeout, when encountering a marked extent_buffer, zero it out.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:02 +01:00
Johannes Thumshirn
cbf44cd93d btrfs: rename EXTENT_BUFFER_NO_CHECK to EXTENT_BUFFER_ZONED_ZEROOUT
EXTENT_BUFFER_ZONED_ZEROOUT better describes the state of the extent buffer,
namely it is written as all zeros. This is needed in zoned mode, to
preserve I/O ordering.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:02 +01:00
Filipe Manana
7dc66abb5a btrfs: use a dedicated data structure for chunk maps
Currently we abuse the extent_map structure for two purposes:

1) To actually represent extents for inodes;
2) To represent chunk mappings.

This is odd and has several disadvantages:

1) To create a chunk map, we need to do two memory allocations: one for
   an extent_map structure and another one for a map_lookup structure, so
   more potential for an allocation failure and more complicated code to
   manage and link two structures;

2) For a chunk map we actually only use 3 fields (24 bytes) of the
   respective extent map structure: the 'start' field to have the logical
   start address of the chunk, the 'len' field to have the chunk's size,
   and the 'orig_block_len' field to contain the chunk's stripe size.

   Besides wasting a memory, it's also odd and not intuitive at all to
   have the stripe size in a field named 'orig_block_len'.

   We are also using 'block_len' of the extent_map structure to contain
   the chunk size, so we have 2 fields for the same value, 'len' and
   'block_len', which is pointless;

3) When an extent map is associated to a chunk mapping, we set the bit
   EXTENT_FLAG_FS_MAPPING on its flags and then make its member named
   'map_lookup' point to the associated map_lookup structure. This means
   that for an extent map associated to an inode extent, we are not using
   this 'map_lookup' pointer, so wasting 8 bytes (on a 64 bits platform);

4) Extent maps associated to a chunk mapping are never merged or split so
   it's pointless to use the existing extent map infrastructure.

So add a dedicated data structure named 'btrfs_chunk_map' to represent
chunk mappings, this is basically the existing map_lookup structure with
some extra fields:

1) 'start' to contain the chunk logical address;
2) 'chunk_len' to contain the chunk's length;
3) 'stripe_size' for the stripe size;
4) 'rb_node' for insertion into a rb tree;
5) 'refs' for reference counting.

This way we do a single memory allocation for chunk mappings and we don't
waste memory for them with unused/unnecessary fields from an extent_map.

We also save 8 bytes from the extent_map structure by removing the
'map_lookup' pointer, so the size of struct extent_map is reduced from
144 bytes down to 136 bytes, and we can now have 30 extents map per 4K
page instead of 28.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:02 +01:00
Filipe Manana
6000d9313f btrfs: remove log_extents_lock and logged_list from struct btrfs_root
The logged_list[2] and log_extents_lock[2] members of struct btrfs_root
are no longer used, their last use was removed in commit 5636cf7d6d
("btrfs: remove the logged extents infrastructure"). So remove these
fields. This reduces the size of struct btrfs_root, on a release kernel,
from 1392 bytes down to 1352 bytes.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 20:27:00 +01:00
Boris Burkov
b321a52cce btrfs: free qgroup pertrans reserve on transaction abort
If we abort a transaction, we never run the code that frees the pertrans
qgroup reservation. This results in warnings on unmount as that
reservation has been leaked. The leak isn't a huge issue since the fs is
read-only, but it's better to clean it up when we know we can/should. Do
it during the cleanup_transaction step of aborting.

CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-06 22:32:49 +01:00
Qu Wenruo
2db313205f btrfs: add dmesg output for first mount and last unmount of a filesystem
There is a feature request to add dmesg output when unmounting a btrfs.
There are several alternative methods to do the same thing, but with
their own problems:

- Use eBPF to watch btrfs_put_super()/open_ctree()
  Not end user friendly, they have to dip their head into the source
  code.

- Watch for directory /sys/fs/<uuid>/
  This is way more simple, but still requires some simple device -> uuid
  lookups.  And a script needs to use inotify to watch /sys/fs/.

Compared to all these, directly outputting the information into dmesg
would be the most simple one, with both device and UUID included.

And since we're here, also add the output when mounting a filesystem for
the first time for parity. A more fine grained monitoring of subvolume
mounts should be done by another layer, like audit.

Now mounting a btrfs with all default mkfs options would look like this:

  [81.906566] BTRFS info (device dm-8): first mount of filesystem 633b5c16-afe3-4b79-b195-138fe145e4f2
  [81.907494] BTRFS info (device dm-8): using crc32c (crc32c-intel) checksum algorithm
  [81.908258] BTRFS info (device dm-8): using free space tree
  [81.912644] BTRFS info (device dm-8): auto enabling async discard
  [81.913277] BTRFS info (device dm-8): checking UUID tree
  [91.668256] BTRFS info (device dm-8): last unmount of filesystem 633b5c16-afe3-4b79-b195-138fe145e4f2

CC: stable@vger.kernel.org # 5.4+
Link: https://github.com/kdave/btrfs-progs/issues/689
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
2023-11-23 22:27:26 +01:00
Filipe Manana
0124855ff1 btrfs: add and use helpers for reading and writing last_trans_committed
Currently the last_trans_committed field of struct btrfs_fs_info is
modified and read without any locking or other protection. For example
early in the fsync path, skip_inode_logging() is called which reads
fs_info->last_trans_committed, but at the same time we can have a
transaction commit completing and updating that field.

In the case of an fsync this is harmless and any data race should be
rare and at most cause an unnecessary logging of an inode.

To avoid data race warnings from tools like KCSAN and other issues such
as load and store tearing (amongst others, see [1]), create helpers to
access the last_trans_committed field of struct btrfs_fs_info using
READ_ONCE() and WRITE_ONCE(), and use these helpers everywhere.

[1] https://lwn.net/Articles/793253/

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:17 +02:00
Filipe Manana
6008859b6c btrfs: add and use helpers for reading and writing log_transid
Currently the log_transid field of a root is always modified while holding
the root's log_mutex locked. Most readers of a root's log_transid are also
holding the root's log_mutex locked, however there is one exception which
is btrfs_set_inode_last_trans() where we don't take the lock to avoid
blocking several operations if log syncing is happening in parallel.

Any races here should be harmless, and in the worst case they may cause a
fsync to log an inode when it's not really needed, so nothing bad from a
functional perspective.

To avoid data race warnings from tools like KCSAN and other issues such
as load and store tearing (amongst others, see [1]), create helpers to
access the log_transid field of a root using READ_ONCE() and WRITE_ONCE(),
and use these helpers where needed.

[1] https://lwn.net/Articles/793253/

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:17 +02:00
Filipe Manana
f985078796 btrfs: add and use helpers for reading and writing last_log_commit
Currently, the last_log_commit of a root can be accessed concurrently
without any lock protection. Readers can be calling btrfs_inode_in_log()
early in a fsync call, which reads a root's last_log_commit, while a
writer can change the last_log_commit while a log tree if being synced,
at btrfs_sync_log(). Any races here should be harmless, and in the worst
case they may cause a fsync to log an inode when it's not really needed,
so nothing bad from a functional perspective.

To avoid data race warnings from tools like KCSAN and other issues such
as load and store tearing (amongst others, see [1]), create helpers to
access the last_log_commit field of a root using READ_ONCE() and
WRITE_ONCE(), and use these helpers everywhere.

[1] https://lwn.net/Articles/793253/

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:17 +02:00
Anand Jain
a5b8a5f9f8 btrfs: support cloned-device mount capability
Guilherme's previous work [1] aimed at the mounting of cloned devices
using a superblock flag SINGLE_DEV during mkfs.
 [1] https://lore.kernel.org/linux-btrfs/20230831001544.3379273-1-gpiccoli@igalia.com/

Building upon this work, here is in memory only approach. As it mounts
we determine if the same fsid is already mounted if then we generate a
random temp fsid which shall be used the mount, in memory only not
written to the disk. We distinguish devices by devt.

Example:
  $ fallocate -l 300m ./disk1.img
  $ mkfs.btrfs -f ./disk1.img
  $ cp ./disk1.img ./disk2.img
  $ cp ./disk1.img ./disk3.img
  $ mount -o loop ./disk1.img /btrfs
  $ mount -o ./disk2.img /btrfs1
  $ mount -o ./disk3.img /btrfs2

  $ btrfs fi show -m
  Label: none  uuid: 4a212b48-1bec-46a5-938a-783c8c1f0b02
	Total devices 1 FS bytes used 144.00KiB
	devid    1 size 300.00MiB used 88.00MiB path /dev/loop0

  Label: none  uuid: adabf2fe-5515-4ad0-95b4-7b1609218c16
	Total devices 1 FS bytes used 144.00KiB
	devid    1 size 300.00MiB used 88.00MiB path /dev/loop1

  Label: none  uuid: 1d77d0df-7d92-439e-adbd-20b9b86fdedb
	Total devices 1 FS bytes used 144.00KiB
	devid    1 size 300.00MiB used 88.00MiB path /dev/loop2

Co-developed-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:17 +02:00
Filipe Manana
f66e0209bd btrfs: stop reserving excessive space for block group item updates
Space for block group item updates, necessary after allocating or
deallocating an extent from a block group, is reserved in the delayed
refs block reserve. Currently we do this by incrementing the transaction
handle's delayed_ref_updates counter and then calling
btrfs_update_delayed_refs_rsv(), which will increase the size of the
delayed refs block reserve by an amount that corresponds to the same
amount we use for delayed refs, given by btrfs_calc_delayed_ref_bytes().

That is an excessive amount because it corresponds to the amount of space
needed to insert one item in a btree (btrfs_calc_insert_metadata_size())
times 2 when the free space tree feature is enabled. All we need is an
amount as given by btrfs_calc_metadata_size(), since we only need to
update an existing block group item in the extent tree (or block group
tree if this feature is enabled). By using btrfs_calc_metadata_size() we
will need to reserve 4 times less space when using the free space tree
and 2 times less space when not using it, putting less pressure on space
reservation.

So use helpers to reserve and release space for block group item updates
that use btrfs_calc_metadata_size() for calculation of the space.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:16 +02:00
Anand Jain
197a9ecee6 btrfs: reject devices with CHANGING_FSID_V2
The BTRFS_SUPER_FLAG_CHANGING_FSID_V2 flag indicates a transient state
where the device in the userspace btrfstune -m|-M operation failed to
complete changing the fsid.

This flag makes the kernel to automatically determine the other
partner devices to which a given device can be associated, based on the
fsid, metadata_uuid and generation values.

btrfstune -m|M feature is especially useful in virtual cloud setups, where
compute instances (disk images) are quickly copied, fsid changed, and
launched. Given numerous disk images with the same metadata_uuid but
different fsid, there's no clear way a device can be correctly assembled
with the proper partners when the CHANGING_FSID_V2 flag is set. So, the
disk could be assembled incorrectly, as in the example below:

Before this patch:

Consider the following two filesystems:
   /dev/loop[2-3] are raw copies of /dev/loop[0-1] and the btrsftune -m
operation fails.

In this scenario, as the /dev/loop0's fsid change is interrupted, and the
CHANGING_FSID_V2 flag is set as shown below.

  $ p="device|devid|^metadata_uuid|^fsid|^incom|^generation|^flags"

  $ btrfs inspect dump-super /dev/loop0 | egrep '$p'
  superblock: bytenr=65536, device=/dev/loop0
  flags			0x1000000001
  fsid			7d4b4b93-2b27-4432-b4e4-4be1fbccbd45
  metadata_uuid		bb040a9f-233a-4de2-ad84-49aa5a28059b
  generation		9
  num_devices		2
  incompat_flags	0x741
  dev_item.devid	1

  $ btrfs inspect dump-super /dev/loop1 | egrep '$p'
  superblock: bytenr=65536, device=/dev/loop1
  flags			0x1
  fsid			11d2af4d-1b71-45a9-83f6-f2100766939d
  metadata_uuid		bb040a9f-233a-4de2-ad84-49aa5a28059b
  generation		10
  num_devices		2
  incompat_flags	0x741
  dev_item.devid	2

  $ btrfs inspect dump-super /dev/loop2 | egrep '$p'
  superblock: bytenr=65536, device=/dev/loop2
  flags			0x1
  fsid			7d4b4b93-2b27-4432-b4e4-4be1fbccbd45
  metadata_uuid		bb040a9f-233a-4de2-ad84-49aa5a28059b
  generation		8
  num_devices		2
  incompat_flags	0x741
  dev_item.devid	1

  $ btrfs inspect dump-super /dev/loop3 | egrep '$p'
  superblock: bytenr=65536, device=/dev/loop3
  flags			0x1
  fsid			7d4b4b93-2b27-4432-b4e4-4be1fbccbd45
  metadata_uuid		bb040a9f-233a-4de2-ad84-49aa5a28059b
  generation		8
  num_devices		2
  incompat_flags	0x741
  dev_item.devid	2

It is normal that some devices aren't instantly discovered during
system boot or iSCSI discovery. The controlled scan below demonstrates
this.

  $ btrfs device scan --forget
  $ btrfs device scan /dev/loop0
  Scanning for btrfs filesystems on '/dev/loop0'
  $ mount /dev/loop3 /btrfs
  $ btrfs filesystem show -m
  Label: none  uuid: 7d4b4b93-2b27-4432-b4e4-4be1fbccbd45
	Total devices 2 FS bytes used 144.00KiB
	devid    1 size 300.00MiB used 48.00MiB path /dev/loop0
	devid    2 size 300.00MiB used 40.00MiB path /dev/loop3

/dev/loop0 and /dev/loop3 are incorrectly partnered.

This kernel patch removes functions and code connected to the
CHANGING_FSID_V2 flag.

With this patch, now devices with the CHANGING_FSID_V2 flag are rejected.
And its partner will fail to mount with the extra -o degraded option.
The check is removed from open_ctree(), devices are rejected during
scanning which in turn fails the mount.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:13 +02:00
Boris Burkov
e076145115 btrfs: qgroup: only set QUOTA_ENABLED when done reading qgroups
In open_ctree, we set BTRFS_FS_QUOTA_ENABLED as soon as we see a
quota_root, as opposed to after we are done setting up the qgroup
structures. In the quota_enable path, we wait until after the structures
are set up. Likewise, in disable, we clear the bit before tearing down
the structures. I feel that this organization is less surprising for the
open_ctree path.

I don't believe this fixes any actual bug, but avoids potential
confusion when using btrfs_qgroup_mode in an intermediate state where we
are enabled but haven't yet setup the qgroup status flags. It also
avoids any risk of calling a qgroup function and attempting to use the
qgroup rbtrees before they exist/are setup.

This all occurs before we do rw setup, so I believe it should be mostly
a no-op.

Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:12 +02:00
Boris Burkov
60ea105a0f btrfs: qgroup: track metadata relocation COW with simple quota
Relocation COWs metadata blocks in two cases for the reloc root:

- copying the subvolume root item when creating the reloc root
- copying a btree node when there is a COW during relocation

In both cases, the resulting btree node hits an abnormal code path with
respect to the owner field in its btrfs_header. It first creates the
root item for the new objectid, which populates the reloc root id, and
it at this point that delayed refs are created.

Later, it fully copies the old node into the new node (including the
original owner field) which overwrites it. This results in a simple
quotas mismatch where we run the delayed ref for the reloc root which
has no simple quota effect (reloc root is not an fstree) but when we
ultimately delete the node, the owner is the real original fstree and we
do free the space.

To work around this without tampering with the behavior of relocation,
add a parameter to btrfs_add_tree_block that lets the relocation code
path specify a different owning root than the "operating" root (in this
case, owning root is the real root and the operating root is the reloc
root). These can naturally be plumbed into delayed refs that have the
same concept.

Note that this is a double count in some sense, but a relatively natural
one, as there are really two extents, and the old one will be deleted
soon. This is consistent with how data relocation extents are accounted
by simple quotas.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:12 +02:00
Johannes Thumshirn
515020900d btrfs: read raid stripe tree from disk
If we find the raid-stripe-tree on mount, read it from disk. This is
a backward incompatible feature. The rescue=ignorebadroots mount option
will skip this tree.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:09 +02:00
Filipe Manana
4ebe8d4788 btrfs: mark transaction id check as unlikely at btrfs_mark_buffer_dirty()
At btrfs_mark_buffer_dirty(), having a transaction id mismatch is never
expected to happen and it usually means there's a bug or some memory
corruption due to a bitflip for example. So mark the condition as unlikely
to optimize code generation as well as to make it obvious for human
readers that it is a very unexpected condition.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:07 +02:00
Filipe Manana
20cbe46035 btrfs: use btrfs_crit at btrfs_mark_buffer_dirty()
There's no need to use WARN() at btrfs_mark_buffer_dirty() to print an
error message, as we have the fs_info pointer we can use btrfs_crit()
which prints device information and makes the message have a more uniform
format. As we are already aborting the transaction we already have a stack
trace printed as well. So replace the use of WARN() with btrfs_crit().

Also slightly reword the message to use 'logical' instead of 'block' as
it's what is used in other error/warning messages.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:07 +02:00
Filipe Manana
50564b651d btrfs: abort transaction on generation mismatch when marking eb as dirty
When marking an extent buffer as dirty, at btrfs_mark_buffer_dirty(),
we check if its generation matches the running transaction and if not we
just print a warning. Such mismatch is an indicator that something really
went wrong and only printing a warning message (and stack trace) is not
enough to prevent a corruption. Allowing a transaction to commit with such
an extent buffer will trigger an error if we ever try to read it from disk
due to a generation mismatch with its parent generation.

So abort the current transaction with -EUCLEAN if we notice a generation
mismatch. For this we need to pass a transaction handle to
btrfs_mark_buffer_dirty() which is always available except in test code,
in which case we can pass NULL since it operates on dummy extent buffers
and all test roots have a single node/leaf (root node at level 0).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:07 +02:00
Filipe Manana
adb86dbe42 btrfs: stop doing excessive space reservation for csum deletion
Currently when reserving space for deleting the csum items for a data
extent, when adding or updating a delayed ref head, we determine how
many leaves of csum items we can have and then pass that number to the
helper btrfs_calc_delayed_ref_bytes(). This helper is used for calculating
space for all tree modifications we need when running delayed references,
however the amount of space it computes is excessive for deleting csum
items because:

1) It uses btrfs_calc_insert_metadata_size() which is excessive because
   we only need to delete csum items from the csum tree, we don't need
   to insert any items, so btrfs_calc_metadata_size() is all we need (as
   it computes space needed to delete an item);

2) If the free space tree is enabled, it doubles the amount of space,
   which is pointless for csum deletion since we don't need to touch the
   free space tree or any other tree other than the csum tree.

So improve on this by tracking how many csum deletions we have and using
a new helper to calculate space for csum deletions (just a wrapper around
btrfs_calc_metadata_size() with a comment). This reduces the amount of
space we need to reserve for csum deletions by a factor of 4, and it helps
reduce the number of times we have to block space reservations and have
the reclaim task enter the space flushing algorithm (flush delayed items,
flush delayed refs, etc) in order to satisfy tickets.

For example this results in a total time decrease when unlinking (or
truncating) files with many extents, as we end up having to block on space
metadata reservations less often. Example test:

  $ cat test.sh
  #!/bin/bash

  DEV=/dev/nullb0
  MNT=/mnt/test

  umount $DEV &> /dev/null
  mkfs.btrfs -f $DEV
  # Use compression to quickly create files with a lot of extents
  # (each with a size of 128K).
  mount -o compress=lzo $DEV $MNT

  # 100G gives at least 983040 extents with a size of 128K.
  xfs_io -f -c "pwrite -S 0xab -b 1M 0 120G" $MNT/foobar

  # Flush all delalloc and clear all metadata from memory.
  umount $MNT
  mount -o compress=lzo $DEV $MNT

  start=$(date +%s%N)
  rm -f $MNT/foobar
  end=$(date +%s%N)
  dur=$(( (end - start) / 1000000 ))
  echo "rm took $dur milliseconds"

  umount $MNT

Before this change rm took: 7504 milliseconds
After this change rm took:  6574 milliseconds  (-12.4%)

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-10-12 16:44:06 +02:00