From: Josef Bacik josef@toxicpanda.com
stable inclusion from stable-5.10.67 commit 0901af53da8f4cfee3bb364a35f66d0d4a9b93ba bugzilla: 182619 https://gitee.com/openeuler/kernel/issues/I4EWO7
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit ac98141d140444fe93e26471d3074c603b70e2ca upstream.
We use the async_delalloc_pages mechanism to make sure that we've completed our async work before trying to continue our delalloc flushing. The reason for this is we need to see any ordered extents that were created by our delalloc flushing. However we're waking up before we do the submit work, which is before we create the ordered extents. This is a pretty wide race window where we could potentially think there are no ordered extents and thus exit shrink_delalloc prematurely. Fix this by waking us up after we've done the work to create ordered extents.
CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Nikolay Borisov nborisov@suse.com Signed-off-by: Josef Bacik josef@toxicpanda.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- fs/btrfs/inode.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 69c6786a9fdf..ff3f0638cdb9 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1202,11 +1202,6 @@ static noinline void async_cow_submit(struct btrfs_work *work) nr_pages = (async_chunk->end - async_chunk->start + PAGE_SIZE) >> PAGE_SHIFT;
- /* atomic_sub_return implies a barrier */ - if (atomic_sub_return(nr_pages, &fs_info->async_delalloc_pages) < - 5 * SZ_1M) - cond_wake_up_nomb(&fs_info->async_submit_wait); - /* * ->inode could be NULL if async_chunk_start has failed to compress, * in which case we don't have anything to submit, yet we need to @@ -1215,6 +1210,11 @@ static noinline void async_cow_submit(struct btrfs_work *work) */ if (async_chunk->inode) submit_compressed_extents(async_chunk); + + /* atomic_sub_return implies a barrier */ + if (atomic_sub_return(nr_pages, &fs_info->async_delalloc_pages) < + 5 * SZ_1M) + cond_wake_up_nomb(&fs_info->async_submit_wait); }
static noinline void async_cow_free(struct btrfs_work *work)