FAILED: patch "[PATCH] btrfs: zoned: skip reporting zone for new block group" failed to apply to 6.14-stable tree
Subsystems (2)
[email protected]
maintainerThe patch below does not apply to the 6.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.14.y
git checkout FETCH_HEAD
git cherry-pick -x 866bafae59ecffcf1840d846cd79740be29f21d6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025042836-balance-molehill-5c30@gregkh' --subject-prefix 'PATCH 6.14.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 866bafae59ecffcf1840d846cd79740be29f21d6 Mon Sep 17 00:00:00 2001
From: Naohiro Aota <[email protected]>
Date: Wed, 19 Mar 2025 10:49:17 +0900
Subject: [PATCH] btrfs: zoned: skip reporting zone for new block group
There is a potential deadlock if we do report zones in an IO context, detailed in below lockdep report. When one process do a report zones and another process freezes the block device, the report zones side cannot allocate a tag because the freeze is already started. This can thus result in new block group creation to hang forever, blocking the write path.
Thankfully, a new block group should be created on empty zones. So, reporting the zones is not necessary and we can set the write pointer = 0 and load the zone capacity from the block layer using bdev_zone_capacity() helper.
======================================================
WARNING: possible circular locking dependency detected
6.14.0-rc1 #252 Not tainted
------------------------------------------------------
modprobe/1110 is trying to acquire lock:
ffff888100ac83e0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: __flush_work+0x38f/0xb60
but task is already holding lock:
ffff8881205b6f20 (&q->q_usage_counter(queue)#16){++++}-{0:0}, at: sd_remove+0x85/0x130
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&q->q_usage_counter(queue)#16){++++}-{0:0}:
blk_queue_enter+0x3d9/0x500
blk_mq_alloc_request+0x47d/0x8e0
scsi_execute_cmd+0x14f/0xb80
sd_zbc_do_report_zones+0x1c1/0x470
sd_zbc_report_zones+0x362/0xd60
blkdev_report_zones+0x1b1/0x2e0
btrfs_get_dev_zones+0x215/0x7e0 [btrfs]
btrfs_load_block_group_zone_info+0x6d2/0x2c10 [btrfs]
btrfs_make_block_group+0x36b/0x870 [btrfs]
btrfs_create_chunk+0x147d/0x2320 [btrfs]
btrfs_chunk_alloc+0x2ce/0xcf0 [btrfs]
start_transaction+0xce6/0x1620 [btrfs]
btrfs_uuid_scan_kthread+0x4ee/0x5b0 [btrfs]
kthread+0x39d/0x750
ret_from_fork+0x30/0x70
ret_from_fork_asm+0x1a/0x30-> #2 (&fs_info->dev_replace.rwsem){++++}-{4:4}:
down_read+0x9b/0x470
btrfs_map_block+0x2ce/0x2ce0 [btrfs]
btrfs_submit_chunk+0x2d4/0x16c0 [btrfs]
btrfs_submit_bbio+0x16/0x30 [btrfs]
btree_write_cache_pages+0xb5a/0xf90 [btrfs]
do_writepages+0x17f/0x7b0
__writeback_single_inode+0x114/0xb00
writeback_sb_inodes+0x52b/0xe00
wb_writeback+0x1a7/0x800
wb_workfn+0x12a/0xbd0
process_one_work+0x85a/0x1460
worker_thread+0x5e2/0xfc0
kthread+0x39d/0x750
ret_from_fork+0x30/0x70
ret_from_fork_asm+0x1a/0x30-> #1 (&fs_info->zoned_meta_io_lock){+.+.}-{4:4}:
__mutex_lock+0x1aa/0x1360
btree_write_cache_pages+0x252/0xf90 [btrfs]
do_writepages+0x17f/0x7b0
__writeback_single_inode+0x114/0xb00
writeback_sb_inodes+0x52b/0xe00
wb_writeback+0x1a7/0x800
wb_workfn+0x12a/0xbd0
process_one_work+0x85a/0x1460
worker_thread+0x5e2/0xfc0
kthread+0x39d/0x750
ret_from_fork+0x30/0x70
ret_from_fork_asm+0x1a/0x30-> #0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}:
__lock_acquire+0x2f52/0x5ea0
lock_acquire+0x1b1/0x540
__flush_work+0x3ac/0xb60
wb_shutdown+0x15b/0x1f0
bdi_unregister+0x172/0x5b0
del_gendisk+0x841/0xa20
sd_remove+0x85/0x130
device_release_driver_internal+0x368/0x520
bus_remove_device+0x1f1/0x3f0
device_del+0x3bd/0x9c0
__scsi_remove_device+0x272/0x340
scsi_forget_host+0xf7/0x170
scsi_remove_host+0xd2/0x2a0
sdebug_driver_remove+0x52/0x2f0 [scsi_debug]
device_release_driver_internal+0x368/0x520
bus_remove_device+0x1f1/0x3f0
device_del+0x3bd/0x9c0
device_unregister+0x13/0xa0
sdebug_do_remove_host+0x1fb/0x290 [scsi_debug]
scsi_debug_exit+0x17/0x70 [scsi_debug]
__do_sys_delete_module.isra.0+0x321/0x520
do_syscall_64+0x93/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7eother info that might help us debug this:
Chain exists of: (work_completion)(&(&wb->dwork)->work) --> &fs_info->dev_replace.rwsem --> &q->q_usage_counter(queue)#16 Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&q->q_usage_counter(queue)#16);
lock(&fs_info->dev_replace.rwsem);
lock(&q->q_usage_counter(queue)#16);lock((work_completion)(&(&wb->dwork)->work));
*** DEADLOCK ***
5 locks held by modprobe/1110:
#0: ffff88811f7bc108 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0x8f/0x520 #1: ffff8881022ee0e0 (&shost->scan_mutex){+.+.}-{4:4}, at: scsi_remove_host+0x20/0x2a0 #2: ffff88811b4c4378 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0x8f/0x520 #3: ffff8881205b6f20 (&q->q_usage_counter(queue)#16){++++}-{0:0}, at: sd_remove+0x85/0x130 #4: ffffffffa3284360 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xda/0xb60
stack backtrace: CPU: 0 UID: 0 PID: 1110 Comm: modprobe Not tainted 6.14.0-rc1 #252 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x6a/0x90 print_circular_bug.cold+0x1e0/0x274 check_noncircular+0x306/0x3f0 ? __pfx_check_noncircular+0x10/0x10 ? mark_lock+0xf5/0x1650 ? __pfx_check_irq_usage+0x10/0x10 ? lockdep_lock+0xca/0x1c0 ? __pfx_lockdep_lock+0x10/0x10 __lock_acquire+0x2f52/0x5ea0 ? __pfx___lock_acquire+0x10/0x10 ? __pfx_mark_lock+0x10/0x10 lock_acquire+0x1b1/0x540 ? __flush_work+0x38f/0xb60 ? __pfx_lock_acquire+0x10/0x10 ? __pfx_lock_release+0x10/0x10 ? mark_held_locks+0x94/0xe0 ? __flush_work+0x38f/0xb60 __flush_work+0x3ac/0xb60 ? __flush_work+0x38f/0xb60 ? __pfx_mark_lock+0x10/0x10 ? __pfx___flush_work+0x10/0x10 ? __pfx_wq_barrier_func+0x10/0x10 ? __pfx___might_resched+0x10/0x10 ? mark_held_locks+0x94/0xe0 wb_shutdown+0x15b/0x1f0 bdi_unregister+0x172/0x5b0 ? __pfx_bdi_unregister+0x10/0x10 ? up_write+0x1ba/0x510 del_gendisk+0x841/0xa20 ? __pfx_del_gendisk+0x10/0x10 ? _raw_spin_unlock_irqrestore+0x35/0x60 ? __pm_runtime_resume+0x79/0x110 sd_remove+0x85/0x130 device_release_driver_internal+0x368/0x520 ? kobject_put+0x5d/0x4a0 bus_remove_device+0x1f1/0x3f0 device_del+0x3bd/0x9c0 ? __pfx_device_del+0x10/0x10 __scsi_remove_device+0x272/0x340 scsi_forget_host+0xf7/0x170 scsi_remove_host+0xd2/0x2a0 sdebug_driver_remove+0x52/0x2f0 [scsi_debug] ? kernfs_remove_by_name_ns+0xc0/0xf0 device_release_driver_internal+0x368/0x520 ? kobject_put+0x5d/0x4a0 bus_remove_device+0x1f1/0x3f0 device_del+0x3bd/0x9c0 ? __pfx_device_del+0x10/0x10 ? __pfx___mutex_unlock_slowpath+0x10/0x10 device_unregister+0x13/0xa0 sdebug_do_remove_host+0x1fb/0x290 [scsi_debug] scsi_debug_exit+0x17/0x70 [scsi_debug] __do_sys_delete_module.isra.0+0x321/0x520 ? __pfx___do_sys_delete_module.isra.0+0x10/0x10 ? __pfx_slab_free_after_rcu_debug+0x10/0x10 ? kasan_save_stack+0x2c/0x50 ? kasan_record_aux_stack+0xa3/0xb0 ? __call_rcu_common.constprop.0+0xc4/0xfb0 ? kmem_cache_free+0x3a0/0x590 ? __x64_sys_close+0x78/0xd0 do_syscall_64+0x93/0x180 ? lock_is_held_type+0xd5/0x130 ? __call_rcu_common.constprop.0+0x3c0/0xfb0 ? lockdep_hardirqs_on+0x78/0x100 ? __call_rcu_common.constprop.0+0x3c0/0xfb0 ? __pfx___call_rcu_common.constprop.0+0x10/0x10 ? kmem_cache_free+0x3a0/0x590 ? lockdep_hardirqs_on_prepare+0x16d/0x400 ? do_syscall_64+0x9f/0x180 ? lockdep_hardirqs_on+0x78/0x100 ? do_syscall_64+0x9f/0x180 ? __pfx___x64_sys_openat+0x10/0x10 ? lockdep_hardirqs_on_prepare+0x16d/0x400 ? do_syscall_64+0x9f/0x180 ? lockdep_hardirqs_on+0x78/0x100 ? do_syscall_64+0x9f/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f436712b68b RSP: 002b:00007ffe9f1a8658 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 00005559b367fd80 RCX: 00007f436712b68b RDX: 0000000000000000 RSI: 0000000000000800 RDI: 00005559b367fde8 RBP: 00007ffe9f1a8680 R08: 1999999999999999 R09: 0000000000000000 R10: 00007f43671a5fe0 R11: 0000000000000206 R12: 0000000000000000 R13: 00007ffe9f1a86b0 R14: 0000000000000000 R15: 0000000000000000 </TASK>
fs/btrfs/zoned.c +16 -2
@@ -1277,7 +1277,7 @@ struct zone_info {static int btrfs_load_zone_info (struct btrfs_fs_info *fs_info,int zone_idx,struct zone_info *info,unsigned long *active, -struct btrfs_chunk_map *map) +struct btrfs_chunk_map *map,bool new) {struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;struct btrfs_device *device;
@@ -1307,6 +1307,8 @@ static int btrfs_load_zone_info(struct btrfs_fs_info *fs_info, int zone_idx,return 0 ; } +ASSERT (!new ||btrfs_dev_is_empty_zone (device, info->physical)); +/* This zone will be used for allocation, so mark this zone non-empty. */ btrfs_dev_clear_zone_empty (device, info->physical);
@@ -1319,6 +1321,18 @@ static int btrfs_load_zone_info(struct btrfs_fs_info *fs_info, int zone_idx,* to determine the allocation offset within the zone. */ WARN_ON (!IS_ALIGNED (info->physical, fs_info->zone_size)); + +if (new) { +sector_t capacity; + + capacity =bdev_zone_capacity (device->bdev, info->physical >>SECTOR_SHIFT ); +up_read (&dev_replace->rwsem); + info->alloc_offset =0 ; + info->capacity = capacity <<SECTOR_SHIFT ; + +return 0 ; + } + nofs_flag =memalloc_nofs_save (); ret =btrfs_get_dev_zone (device, info->physical, &zone);memalloc_nofs_restore (nofs_flag);
@@ -1588,7 +1602,7 @@ int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache, bool new) }for (i =0 ; i < map->num_stripes; i++) { - ret =btrfs_load_zone_info (fs_info, i, &zone_info[i], active, map); + ret =btrfs_load_zone_info (fs_info, i, &zone_info[i], active, map, new);if (ret) goto out;