fs/btrfs/dev-replace.c | 2 ++ fs/btrfs/fs.h | 2 ++ fs/btrfs/volumes.c | 8 +++++--- 3 files changed, 9 insertions(+), 3 deletions(-)
From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
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:
<TASK>
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
</TASK>
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 <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
fs/btrfs/dev-replace.c | 2 ++
fs/btrfs/fs.h | 2 ++
fs/btrfs/volumes.c | 8 +++++---
3 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 83d5cdd77f29..604399e59a3d 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -641,6 +641,7 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
return ret;
down_write(&dev_replace->rwsem);
+ dev_replace->replace_task = current;
switch (dev_replace->replace_state) {
case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
@@ -994,6 +995,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
list_add(&tgt_device->dev_alloc_list, &fs_devices->alloc_list);
fs_devices->rw_devices++;
+ dev_replace->replace_task = NULL;
up_write(&dev_replace->rwsem);
btrfs_rm_dev_replace_blocked(fs_info);
diff --git a/fs/btrfs/fs.h b/fs/btrfs/fs.h
index 79f64e383edd..cbfb225858a5 100644
--- a/fs/btrfs/fs.h
+++ b/fs/btrfs/fs.h
@@ -317,6 +317,8 @@ struct btrfs_dev_replace {
struct percpu_counter bio_counter;
wait_queue_head_t replace_wait;
+
+ struct task_struct *replace_task;
};
/*
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 8f340ad1d938..995b0647f538 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6480,13 +6480,15 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
max_len = btrfs_max_io_len(map, map_offset, &io_geom);
*length = min_t(u64, map->chunk_len - map_offset, max_len);
- down_read(&dev_replace->rwsem);
+ if (dev_replace->replace_task != current)
+ down_read(&dev_replace->rwsem);
+
dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
/*
* Hold the semaphore for read during the whole operation, write is
* requested at commit time but must wait.
*/
- if (!dev_replace_is_ongoing)
+ if (!dev_replace_is_ongoing && dev_replace->replace_task != current)
up_read(&dev_replace->rwsem);
switch (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
@@ -6626,7 +6628,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
bioc->mirror_num = io_geom.mirror_num;
out:
- if (dev_replace_is_ongoing) {
+ if (dev_replace_is_ongoing && dev_replace->replace_task != current) {
lockdep_assert_held(&dev_replace->rwsem);
/* Unlock and let waiting writers proceed */
up_read(&dev_replace->rwsem);
--
2.43.0On Tue, Sep 10, 2024 at 8:55 AM Johannes Thumshirn <jth@kernel.org> wrote:
>
> From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
>
> 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:
> <TASK>
> 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
> </TASK>
>
> 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 <fdmanana@suse.com>
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Looks good, thanks.
The review applies regardless of using task_struct or pid_t.
> ---
> fs/btrfs/dev-replace.c | 2 ++
> fs/btrfs/fs.h | 2 ++
> fs/btrfs/volumes.c | 8 +++++---
> 3 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
> index 83d5cdd77f29..604399e59a3d 100644
> --- a/fs/btrfs/dev-replace.c
> +++ b/fs/btrfs/dev-replace.c
> @@ -641,6 +641,7 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
> return ret;
>
> down_write(&dev_replace->rwsem);
> + dev_replace->replace_task = current;
> switch (dev_replace->replace_state) {
> case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
> case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
> @@ -994,6 +995,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
> list_add(&tgt_device->dev_alloc_list, &fs_devices->alloc_list);
> fs_devices->rw_devices++;
>
> + dev_replace->replace_task = NULL;
> up_write(&dev_replace->rwsem);
> btrfs_rm_dev_replace_blocked(fs_info);
>
> diff --git a/fs/btrfs/fs.h b/fs/btrfs/fs.h
> index 79f64e383edd..cbfb225858a5 100644
> --- a/fs/btrfs/fs.h
> +++ b/fs/btrfs/fs.h
> @@ -317,6 +317,8 @@ struct btrfs_dev_replace {
>
> struct percpu_counter bio_counter;
> wait_queue_head_t replace_wait;
> +
> + struct task_struct *replace_task;
> };
>
> /*
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 8f340ad1d938..995b0647f538 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -6480,13 +6480,15 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
> max_len = btrfs_max_io_len(map, map_offset, &io_geom);
> *length = min_t(u64, map->chunk_len - map_offset, max_len);
>
> - down_read(&dev_replace->rwsem);
> + if (dev_replace->replace_task != current)
> + down_read(&dev_replace->rwsem);
> +
> dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
> /*
> * Hold the semaphore for read during the whole operation, write is
> * requested at commit time but must wait.
> */
> - if (!dev_replace_is_ongoing)
> + if (!dev_replace_is_ongoing && dev_replace->replace_task != current)
> up_read(&dev_replace->rwsem);
>
> switch (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
> @@ -6626,7 +6628,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
> bioc->mirror_num = io_geom.mirror_num;
>
> out:
> - if (dev_replace_is_ongoing) {
> + if (dev_replace_is_ongoing && dev_replace->replace_task != current) {
> lockdep_assert_held(&dev_replace->rwsem);
> /* Unlock and let waiting writers proceed */
> up_read(&dev_replace->rwsem);
> --
> 2.43.0
>
>
This is to fold in if we decide to go by pid instead of a task_struct.
---
fs/btrfs/dev-replace.c | 4 ++--
fs/btrfs/fs.h | 3 ++-
fs/btrfs/volumes.c | 8 +++++---
3 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 604399e59a3d..a1efb8de8170 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -641,7 +641,7 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
return ret;
down_write(&dev_replace->rwsem);
- dev_replace->replace_task = current;
+ dev_replace->replace_task = current->pid;
switch (dev_replace->replace_state) {
case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
@@ -995,7 +995,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
list_add(&tgt_device->dev_alloc_list, &fs_devices->alloc_list);
fs_devices->rw_devices++;
- dev_replace->replace_task = NULL;
+ dev_replace->replace_task = 0;
up_write(&dev_replace->rwsem);
btrfs_rm_dev_replace_blocked(fs_info);
diff --git a/fs/btrfs/fs.h b/fs/btrfs/fs.h
index cbfb225858a5..a30978f29a59 100644
--- a/fs/btrfs/fs.h
+++ b/fs/btrfs/fs.h
@@ -3,6 +3,7 @@
#ifndef BTRFS_FS_H
#define BTRFS_FS_H
+#include "linux/types.h"
#include <linux/blkdev.h>
#include <linux/sizes.h>
#include <linux/time64.h>
@@ -318,7 +319,7 @@ struct btrfs_dev_replace {
struct percpu_counter bio_counter;
wait_queue_head_t replace_wait;
- struct task_struct *replace_task;
+ pid_t replace_task;
};
/*
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 995b0647f538..c3f53a59cbf3 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6480,7 +6480,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
max_len = btrfs_max_io_len(map, map_offset, &io_geom);
*length = min_t(u64, map->chunk_len - map_offset, max_len);
- if (dev_replace->replace_task != current)
+ if (dev_replace->replace_task != current->pid)
down_read(&dev_replace->rwsem);
dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
@@ -6488,7 +6488,8 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
* Hold the semaphore for read during the whole operation, write is
* requested at commit time but must wait.
*/
- if (!dev_replace_is_ongoing && dev_replace->replace_task != current)
+ if (!dev_replace_is_ongoing &&
+ dev_replace->replace_task != current->pid)
up_read(&dev_replace->rwsem);
switch (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
@@ -6628,7 +6629,8 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
bioc->mirror_num = io_geom.mirror_num;
out:
- if (dev_replace_is_ongoing && dev_replace->replace_task != current) {
+ if (dev_replace_is_ongoing &&
+ dev_replace->replace_task != current->pid) {
lockdep_assert_held(&dev_replace->rwsem);
/* Unlock and let waiting writers proceed */
up_read(&dev_replace->rwsem);
--
2.43.0
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