linux.git/fs/btrfs/dev-replace.c, branch v6.15

btrfs: return a literal instead of a variable in btrfs_init_dev_replace()

2025-03-18T19:35:49+00:00

This is just a small clean up, it doesn't change how the code works.
Originally this code had a goto so we needed to set "ret = 0;" but now
it returns directly and so we can simplify it a bit by doing a
"return 0;" and removing the assignment.

Reviewed-by: Anand Jain 
Signed-off-by: Dan Carpenter 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: use BTRFS_PATH_AUTO_FREE in btrfs_run_dev_replace()

2025-03-18T19:35:47+00:00

This is the trivial pattern for path auto free, initialize at the
beginning and free at the end with simple goto -> return conversions.

Reviewed-by: Johannes Thumshirn 
Signed-off-by: David Sterba

btrfs: use BTRFS_PATH_AUTO_FREE in btrfs_init_dev_replace()

2025-03-18T19:35:47+00:00

This is the trivial pattern for path auto free, initialize at the
beginning and free at the end with simple goto -> return conversions.

Reviewed-by: Johannes Thumshirn 
Signed-off-by: David Sterba

btrfs: dev-replace: remove unnecessary call to btrfs_mark_buffer_dirty()

2025-01-13T13:53:19+00:00

The call to btrfs_mark_buffer_dirty() at btrfs_run_dev_replace() is not
necessary as we have a path setup for writing with btrfs_search_slot()
having a 'cow' argument set to 1.

This just makes the code more verbose, confusing and add a little extra
overhead and well as increase the module's text size, so remove it.

Reviewed-by: Johannes Thumshirn 
Signed-off-by: Filipe Manana 
Signed-off-by: David Sterba

btrfs: correct typos in multiple comments across various files

2024-11-11T13:34:14+00:00

Fix some confusing spelling errors that were currently identified,
the details are as follows:

	block-group.c: 2800: 	uncompressible 	==> incompressible
	extent-tree.c: 3131:	EXTEMT		==> EXTENT
	extent_io.c: 3124: 	utlizing 	==> utilizing
	extent_map.c: 1323: 	ealier		==> earlier
	extent_map.c: 1325:	possiblity	==> possibility
	fiemap.c: 189:		emmitted	==> emitted
	fiemap.c: 197:		emmitted	==> emitted
	fiemap.c: 203:		emmitted	==> emitted
	transaction.h: 36:	trasaction	==> transaction
	volumes.c: 5312:	filesysmte	==> filesystem
	zoned.c: 1977:		trasnsaction	==> transaction

Signed-off-by: Shen Lichuan 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: don't take dev_replace rwsem on task already holding it

2024-11-11T13:34:12+00:00

Running fstests btrfs/011 with MKFS_OPTIONS="-O rst" to force the usage of
the RAID stripe-tree, we get the following splat from lockdep:

 BTRFS info (device sdd): dev_replace from /dev/sdd (devid 1) to /dev/sdb started

 ============================================
 WARNING: possible recursive locking detected
 6.11.0-rc3-btrfs-for-next #599 Not tainted
 --------------------------------------------
 btrfs/2326 is trying to acquire lock:
 ffff88810f215c98 (&fs_info->dev_replace.rwsem){++++}-{3:3}, at: btrfs_map_block+0x39f/0x2250

 but task is already holding lock:
 ffff88810f215c98 (&fs_info->dev_replace.rwsem){++++}-{3:3}, at: btrfs_map_block+0x39f/0x2250

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&fs_info->dev_replace.rwsem);
   lock(&fs_info->dev_replace.rwsem);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 1 lock held by btrfs/2326:
  #0: ffff88810f215c98 (&fs_info->dev_replace.rwsem){++++}-{3:3}, at: btrfs_map_block+0x39f/0x2250

 stack backtrace:
 CPU: 1 UID: 0 PID: 2326 Comm: btrfs Not tainted 6.11.0-rc3-btrfs-for-next #599
 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
 Call Trace:
  
  dump_stack_lvl+0x5b/0x80
  __lock_acquire+0x2798/0x69d0
  ? __pfx___lock_acquire+0x10/0x10
  ? __pfx___lock_acquire+0x10/0x10
  lock_acquire+0x19d/0x4a0
  ? btrfs_map_block+0x39f/0x2250
  ? __pfx_lock_acquire+0x10/0x10
  ? find_held_lock+0x2d/0x110
  ? lock_is_held_type+0x8f/0x100
  down_read+0x8e/0x440
  ? btrfs_map_block+0x39f/0x2250
  ? __pfx_down_read+0x10/0x10
  ? do_raw_read_unlock+0x44/0x70
  ? _raw_read_unlock+0x23/0x40
  btrfs_map_block+0x39f/0x2250
  ? btrfs_dev_replace_by_ioctl+0xd69/0x1d00
  ? btrfs_bio_counter_inc_blocked+0xd9/0x2e0
  ? __kasan_slab_alloc+0x6e/0x70
  ? __pfx_btrfs_map_block+0x10/0x10
  ? __pfx_btrfs_bio_counter_inc_blocked+0x10/0x10
  ? kmem_cache_alloc_noprof+0x1f2/0x300
  ? mempool_alloc_noprof+0xed/0x2b0
  btrfs_submit_chunk+0x28d/0x17e0
  ? __pfx_btrfs_submit_chunk+0x10/0x10
  ? bvec_alloc+0xd7/0x1b0
  ? bio_add_folio+0x171/0x270
  ? __pfx_bio_add_folio+0x10/0x10
  ? __kasan_check_read+0x20/0x20
  btrfs_submit_bio+0x37/0x80
  read_extent_buffer_pages+0x3df/0x6c0
  btrfs_read_extent_buffer+0x13e/0x5f0
  read_tree_block+0x81/0xe0
  read_block_for_search+0x4bd/0x7a0
  ? __pfx_read_block_for_search+0x10/0x10
  btrfs_search_slot+0x78d/0x2720
  ? __pfx_btrfs_search_slot+0x10/0x10
  ? lock_is_held_type+0x8f/0x100
  ? kasan_save_track+0x14/0x30
  ? __kasan_slab_alloc+0x6e/0x70
  ? kmem_cache_alloc_noprof+0x1f2/0x300
  btrfs_get_raid_extent_offset+0x181/0x820
  ? __pfx_lock_acquire+0x10/0x10
  ? __pfx_btrfs_get_raid_extent_offset+0x10/0x10
  ? down_read+0x194/0x440
  ? __pfx_down_read+0x10/0x10
  ? do_raw_read_unlock+0x44/0x70
  ? _raw_read_unlock+0x23/0x40
  btrfs_map_block+0x5b5/0x2250
  ? __pfx_btrfs_map_block+0x10/0x10
  scrub_submit_initial_read+0x8fe/0x11b0
  ? __pfx_scrub_submit_initial_read+0x10/0x10
  submit_initial_group_read+0x161/0x3a0
  ? lock_release+0x20e/0x710
  ? __pfx_submit_initial_group_read+0x10/0x10
  ? __pfx_lock_release+0x10/0x10
  scrub_simple_mirror.isra.0+0x3eb/0x580
  scrub_stripe+0xe4d/0x1440
  ? lock_release+0x20e/0x710
  ? __pfx_scrub_stripe+0x10/0x10
  ? __pfx_lock_release+0x10/0x10
  ? do_raw_read_unlock+0x44/0x70
  ? _raw_read_unlock+0x23/0x40
  scrub_chunk+0x257/0x4a0
  scrub_enumerate_chunks+0x64c/0xf70
  ? __mutex_unlock_slowpath+0x147/0x5f0
  ? __pfx_scrub_enumerate_chunks+0x10/0x10
  ? bit_wait_timeout+0xb0/0x170
  ? __up_read+0x189/0x700
  ? scrub_workers_get+0x231/0x300
  ? up_write+0x490/0x4f0
  btrfs_scrub_dev+0x52e/0xcd0
  ? create_pending_snapshots+0x230/0x250
  ? __pfx_btrfs_scrub_dev+0x10/0x10
  btrfs_dev_replace_by_ioctl+0xd69/0x1d00
  ? lock_acquire+0x19d/0x4a0
  ? __pfx_btrfs_dev_replace_by_ioctl+0x10/0x10
  ? lock_release+0x20e/0x710
  ? btrfs_ioctl+0xa09/0x74f0
  ? __pfx_lock_release+0x10/0x10
  ? do_raw_spin_lock+0x11e/0x240
  ? __pfx_do_raw_spin_lock+0x10/0x10
  btrfs_ioctl+0xa14/0x74f0
  ? lock_acquire+0x19d/0x4a0
  ? find_held_lock+0x2d/0x110
  ? __pfx_btrfs_ioctl+0x10/0x10
  ? lock_release+0x20e/0x710
  ? do_sigaction+0x3f0/0x860
  ? __pfx_do_vfs_ioctl+0x10/0x10
  ? do_raw_spin_lock+0x11e/0x240
  ? lockdep_hardirqs_on_prepare+0x270/0x3e0
  ? _raw_spin_unlock_irq+0x28/0x50
  ? do_sigaction+0x3f0/0x860
  ? __pfx_do_sigaction+0x10/0x10
  ? __x64_sys_rt_sigaction+0x18e/0x1e0
  ? __pfx___x64_sys_rt_sigaction+0x10/0x10
  ? __x64_sys_close+0x7c/0xd0
  __x64_sys_ioctl+0x137/0x190
  do_syscall_64+0x71/0x140
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
 RIP: 0033:0x7f0bd1114f9b
 Code: Unable to access opcode bytes at 0x7f0bd1114f71.
 RSP: 002b:00007ffc8a8c3130 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f0bd1114f9b
 RDX: 00007ffc8a8c35e0 RSI: 00000000ca289435 RDI: 0000000000000003
 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000007
 R10: 0000000000000008 R11: 0000000000000246 R12: 00007ffc8a8c6c85
 R13: 00000000398e72a0 R14: 0000000000004361 R15: 0000000000000004
  

This happens because on RAID stripe-tree filesystems we recurse back into
btrfs_map_block() on scrub to perform the logical to device physical
mapping.

But as the device replace task is already holding the dev_replace::rwsem
we deadlock.

So don't take the dev_replace::rwsem in case our task is the task performing
the device replace.

Suggested-by: Filipe Manana 
Signed-off-by: Johannes Thumshirn 
Reviewed-by: Filipe Manana 
Signed-off-by: David Sterba

btrfs: more efficient chunk map iteration when device replace finishes

2024-09-10T14:51:17+00:00

When iterating the chunk maps when a device replace finishes we are doing
a full rbtree search for each chunk map, which is not the most efficient
thing to do, wasting CPU time. As we are holding a write lock on the tree
during the whole iteration, we can simply start from the first node in the
tree and then move to the next chunk map by doing a rb_next() call - the
only exception is when we need to reschedule, in which case we have to do
a full rbtree search since we dropped the write lock and the tree may have
changed (chunk maps may have been removed and the tree got rebalanced).
So just do that.

Signed-off-by: Filipe Manana 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: reschedule when updating chunk maps at the end of a device replace

2024-09-10T14:51:17+00:00

At the end of a device replace we must go over all the chunk maps and
update their stripes to point to the target device instead of the source
device. We iterate over the chunk maps while holding a write lock and
we never reschedule, which can result in monopolizing a CPU for too long
and blocking readers for too long (it's a rw lock, non-blocking).

So improve on this by rescheduling if necessary. This is safe because at
this point we are holding the chunk mutex, which means no new chunks can
be allocated and therefore we don't risk missing a new chunk map that
covers a range behind the last one we processed before rescheduling.

Signed-off-by: Filipe Manana 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: simplify range parameters of btrfs_wait_ordered_roots()

2024-07-11T13:33:19+00:00

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

set_blocksize(): switch to passing struct file *

2024-05-02T21:39:44+00:00

Signed-off-by: Al Viro