This is a note to let you know that I've just added the patch titled
btrfs: zoned: skip splitting and logical rewriting on pre-alloc write
to the 6.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-zoned-skip-splitting-and-logical-rewriting-on-.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 34b877bc51be045b3d6792fa6e95e07037b08ed2
Author: Naohiro Aota <naohiro.aota@xxxxxxx>
Date: Sat Aug 19 01:26:07 2023 +0900
btrfs: zoned: skip splitting and logical rewriting on pre-alloc write
[ Upstream commit c02d35d89b317994bd713ba82e160c5e7f22d9c8 ]
When doing a relocation, there is a chance that at the time of
btrfs_reloc_clone_csums(), there is no checksum for the corresponding
region.
In this case, btrfs_finish_ordered_zoned()'s sum points to an invalid item
and so ordered_extent's logical is set to some invalid value. Then,
btrfs_lookup_block_group() in btrfs_zone_finish_endio() failed to find a
block group and will hit an assert or a null pointer dereference as
following.
This can be reprodcued by running btrfs/028 several times (e.g, 4 to 16
times) with a null_blk setup. The device's zone size and capacity is set to
32 MB and the storage size is set to 5 GB on my setup.
KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f]
CPU: 6 PID: 3105720 Comm: kworker/u16:13 Tainted: G W 6.5.0-rc6-kts+ #1
Hardware name: Supermicro Super Server/X10SRL-F, BIOS 2.0 12/17/2015
Workqueue: btrfs-endio-write btrfs_work_helper [btrfs]
RIP: 0010:btrfs_zone_finish_endio.part.0+0x34/0x160 [btrfs]
Code: 41 54 49 89 fc 55 48 89 f5 53 e8 57 7d fc ff 48 8d b8 88 00 00 00 48 89 c3 48 b8 00 00 00 00 00
> 3c 02 00 0f 85 02 01 00 00 f6 83 88 00 00 00 01 0f 84 a8 00 00
RSP: 0018:ffff88833cf87b08 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000011 RSI: 0000000000000004 RDI: 0000000000000088
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffed102877b827
R10: ffff888143bdc13b R11: ffff888125b1cbc0 R12: ffff888143bdc000
R13: 0000000000007000 R14: ffff888125b1cba8 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88881e500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3ed85223d5 CR3: 00000001519b4005 CR4: 00000000001706e0
Call Trace:
<TASK>
? die_addr+0x3c/0xa0
? exc_general_protection+0x148/0x220
? asm_exc_general_protection+0x22/0x30
? btrfs_zone_finish_endio.part.0+0x34/0x160 [btrfs]
? btrfs_zone_finish_endio.part.0+0x19/0x160 [btrfs]
btrfs_finish_one_ordered+0x7b8/0x1de0 [btrfs]
? rcu_is_watching+0x11/0xb0
? lock_release+0x47a/0x620
? btrfs_finish_ordered_zoned+0x59b/0x800 [btrfs]
? __pfx_btrfs_finish_one_ordered+0x10/0x10 [btrfs]
? btrfs_finish_ordered_zoned+0x358/0x800 [btrfs]
? __smp_call_single_queue+0x124/0x350
? rcu_is_watching+0x11/0xb0
btrfs_work_helper+0x19f/0xc60 [btrfs]
? __pfx_try_to_wake_up+0x10/0x10
? _raw_spin_unlock_irq+0x24/0x50
? rcu_is_watching+0x11/0xb0
process_one_work+0x8c1/0x1430
? __pfx_lock_acquire+0x10/0x10
? __pfx_process_one_work+0x10/0x10
? __pfx_do_raw_spin_lock+0x10/0x10
? _raw_spin_lock_irq+0x52/0x60
worker_thread+0x100/0x12c0
? __kthread_parkme+0xc1/0x1f0
? __pfx_worker_thread+0x10/0x10
kthread+0x2ea/0x3c0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x30/0x70
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1b/0x30
</TASK>
On the zoned mode, writing to pre-allocated region means data relocation
write. Such write always uses WRITE command so there is no need of splitting
and rewriting logical address. Thus, we can just skip the function for the
case.
Fixes: cbfce4c7fbde ("btrfs: optimize the logical to physical mapping for zoned writes")
Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 72b90bc19a191..2490301350015 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1707,10 +1707,21 @@ void btrfs_finish_ordered_zoned(struct btrfs_ordered_extent *ordered)
{
struct btrfs_inode *inode = BTRFS_I(ordered->inode);
struct btrfs_fs_info *fs_info = inode->root->fs_info;
- struct btrfs_ordered_sum *sum =
- list_first_entry(&ordered->list, typeof(*sum), list);
- u64 logical = sum->logical;
- u64 len = sum->len;
+ struct btrfs_ordered_sum *sum;
+ u64 logical, len;
+
+ /*
+ * Write to pre-allocated region is for the data relocation, and so
+ * it should use WRITE operation. No split/rewrite are necessary.
+ */
+ if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags))
+ return;
+
+ ASSERT(!list_empty(&ordered->list));
+ /* The ordered->list can be empty in the above pre-alloc case. */
+ sum = list_first_entry(&ordered->list, struct btrfs_ordered_sum, list);
+ logical = sum->logical;
+ len = sum->len;
while (len < ordered->disk_num_bytes) {
sum = list_next_entry(sum, list);
