6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Naohiro Aota <naohiro.aota@xxxxxxx>
commit e30729d4bd4001881be4d1ad4332a5d4985398f8 upstream.
__btrfs_add_free_space_zoned() references and modifies bg's alloc_offset,
ro, and zone_unusable, but without taking the lock. It is mostly safe
because they monotonically increase (at least for now) and this function is
mostly called by a transaction commit, which is serialized by itself.
Still, taking the lock is a safer and correct option and I'm going to add a
change to reset zone_unusable while a block group is still alive. So, add
locking around the operations.
Fixes: 169e0da91a21 ("btrfs: zoned: track unusable bytes for zones")
CC: stable@xxxxxxxxxxxxxxx # 5.15+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/free-space-cache.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2696,15 +2696,16 @@ static int __btrfs_add_free_space_zoned(
u64 offset = bytenr - block_group->start;
u64 to_free, to_unusable;
int bg_reclaim_threshold = 0;
- bool initial = ((size == block_group->length) && (block_group->alloc_offset == 0));
+ bool initial;
u64 reclaimable_unusable;
- WARN_ON(!initial && offset + size > block_group->zone_capacity);
+ spin_lock(&block_group->lock);
+ initial = ((size == block_group->length) && (block_group->alloc_offset == 0));
+ WARN_ON(!initial && offset + size > block_group->zone_capacity);
if (!initial)
bg_reclaim_threshold = READ_ONCE(sinfo->bg_reclaim_threshold);
- spin_lock(&ctl->tree_lock);
if (!used)
to_free = size;
else if (initial)
@@ -2717,7 +2718,9 @@ static int __btrfs_add_free_space_zoned(
to_free = offset + size - block_group->alloc_offset;
to_unusable = size - to_free;
+ spin_lock(&ctl->tree_lock);
ctl->free_space += to_free;
+ spin_unlock(&ctl->tree_lock);
/*
* If the block group is read-only, we should account freed space into
* bytes_readonly.
@@ -2726,11 +2729,8 @@ static int __btrfs_add_free_space_zoned(
block_group->zone_unusable += to_unusable;
WARN_ON(block_group->zone_unusable > block_group->length);
}
- spin_unlock(&ctl->tree_lock);
if (!used) {
- spin_lock(&block_group->lock);
block_group->alloc_offset -= size;
- spin_unlock(&block_group->lock);
}
reclaimable_unusable = block_group->zone_unusable -
@@ -2744,6 +2744,8 @@ static int __btrfs_add_free_space_zoned(
btrfs_mark_bg_to_reclaim(block_group);
}
+ spin_unlock(&block_group->lock);
+
return 0;
}
