6.6-stable review patch. If anyone has any objections, please let me know.
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From: Naohiro Aota naohiro.aota@wdc.com
commit b18f3b60b35a8c01c9a2a0f0d6424c6d73971dc3 upstream.
The btrfs CI reported a lockdep warning as follows by running generic generic/129.
WARNING: possible circular locking dependency detected 6.7.0-rc5+ #1 Not tainted ------------------------------------------------------ kworker/u5:5/793427 is trying to acquire lock: ffff88813256d028 (&cache->lock){+.+.}-{2:2}, at: btrfs_zone_finish_one_bg+0x5e/0x130 but task is already holding lock: ffff88810a23a318 (&fs_info->zone_active_bgs_lock){+.+.}-{2:2}, at: btrfs_zone_finish_one_bg+0x34/0x130 which lock already depends on the new lock.
the existing dependency chain (in reverse order) is: -> #1 (&fs_info->zone_active_bgs_lock){+.+.}-{2:2}: ... -> #0 (&cache->lock){+.+.}-{2:2}: ...
This is because we take fs_info->zone_active_bgs_lock after a block_group's lock in btrfs_zone_activate() while doing the opposite in other places.
Fix the issue by expanding the fs_info->zone_active_bgs_lock's critical section and taking it before a block_group's lock.
Fixes: a7e1ac7bdc5a ("btrfs: zoned: reserve zones for an active metadata/system block group") CC: stable@vger.kernel.org # 6.6 Signed-off-by: Naohiro Aota naohiro.aota@wdc.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/zoned.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)
--- a/fs/btrfs/zoned.c +++ b/fs/btrfs/zoned.c @@ -1975,6 +1975,7 @@ bool btrfs_zone_activate(struct btrfs_bl
map = block_group->physical_map;
+ spin_lock(&fs_info->zone_active_bgs_lock); spin_lock(&block_group->lock); if (test_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE, &block_group->runtime_flags)) { ret = true; @@ -1987,7 +1988,6 @@ bool btrfs_zone_activate(struct btrfs_bl goto out_unlock; }
- spin_lock(&fs_info->zone_active_bgs_lock); for (i = 0; i < map->num_stripes; i++) { struct btrfs_zoned_device_info *zinfo; int reserved = 0; @@ -2007,20 +2007,17 @@ bool btrfs_zone_activate(struct btrfs_bl */ if (atomic_read(&zinfo->active_zones_left) <= reserved) { ret = false; - spin_unlock(&fs_info->zone_active_bgs_lock); goto out_unlock; }
if (!btrfs_dev_set_active_zone(device, physical)) { /* Cannot activate the zone */ ret = false; - spin_unlock(&fs_info->zone_active_bgs_lock); goto out_unlock; } if (!is_data) zinfo->reserved_active_zones--; } - spin_unlock(&fs_info->zone_active_bgs_lock);
/* Successfully activated all the zones */ set_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE, &block_group->runtime_flags); @@ -2028,8 +2025,6 @@ bool btrfs_zone_activate(struct btrfs_bl
/* For the active block group list */ btrfs_get_block_group(block_group); - - spin_lock(&fs_info->zone_active_bgs_lock); list_add_tail(&block_group->active_bg_list, &fs_info->zone_active_bgs); spin_unlock(&fs_info->zone_active_bgs_lock);
@@ -2037,6 +2032,7 @@ bool btrfs_zone_activate(struct btrfs_bl
out_unlock: spin_unlock(&block_group->lock); + spin_unlock(&fs_info->zone_active_bgs_lock); return ret; }