This is a note to let you know that I've just added the patch titled
btrfs: zoned: wait for data BG to be finished on direct IO allocation
to the 6.6-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-wait-for-data-bg-to-be-finished-on-direct-io-allocation.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 776a838f1fa95670c1c1cf7109a898090b473fa3 Mon Sep 17 00:00:00 2001
From: Naohiro Aota <naohiro.aota@xxxxxxx>
Date: Tue, 17 Oct 2023 17:00:31 +0900
Subject: btrfs: zoned: wait for data BG to be finished on direct IO allocation
From: Naohiro Aota <naohiro.aota@xxxxxxx>
commit 776a838f1fa95670c1c1cf7109a898090b473fa3 upstream.
Running the fio command below on a ZNS device results in "Resource
temporarily unavailable" error.
$ sudo fio --name=w --directory=/mnt --filesize=1GB --bs=16MB --numjobs=16 \
--rw=write --ioengine=libaio --iodepth=128 --direct=1
fio: io_u error on file /mnt/w.2.0: Resource temporarily unavailable: write offset=117440512, buflen=16777216
fio: io_u error on file /mnt/w.2.0: Resource temporarily unavailable: write offset=134217728, buflen=16777216
...
This happens because -EAGAIN error returned from btrfs_reserve_extent()
called from btrfs_new_extent_direct() is spilling over to the userland.
btrfs_reserve_extent() returns -EAGAIN when there is no active zone
available. Then, the caller should wait for some other on-going IO to
finish a zone and retry the allocation.
This logic is already implemented for buffered write in cow_file_range(),
but it is missing for the direct IO counterpart. Implement the same logic
for it.
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
Fixes: 2ce543f47843 ("btrfs: zoned: wait until zone is finished when allocation didn't progress")
CC: stable@xxxxxxxxxxxxxxx # 6.1+
Tested-by: Shinichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/inode.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6974,8 +6974,15 @@ static struct extent_map *btrfs_new_exte
int ret;
alloc_hint = get_extent_allocation_hint(inode, start, len);
+again:
ret = btrfs_reserve_extent(root, len, len, fs_info->sectorsize,
0, alloc_hint, &ins, 1, 1);
+ if (ret == -EAGAIN) {
+ ASSERT(btrfs_is_zoned(fs_info));
+ wait_on_bit_io(&inode->root->fs_info->flags, BTRFS_FS_NEED_ZONE_FINISH,
+ TASK_UNINTERRUPTIBLE);
+ goto again;
+ }
if (ret)
return ERR_PTR(ret);
Patches currently in stable-queue which might be from naohiro.aota@xxxxxxx are
queue-6.6/btrfs-zoned-wait-for-data-bg-to-be-finished-on-direct-io-allocation.patch
