Re: [PATCH v2] Revert "fs/ntfs3: Replace inode_trylock with inode_lock"

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

On Tue, Jul 08, 2025 at 09:57:09AM +0200, Konstantin Komarov wrote:
> This reverts commit 69505fe98f198ee813898cbcaf6770949636430b.
>
> Initially, conditional lock acquisition was removed to fix an xfstest bug
> that was observed during internal testing. The deadlock reported by syzbot
> is resolved by reintroducing conditional acquisition. The xfstest bug no
> longer occurs on kernel version 6.16-rc1 during internal testing. I
> assume that changes in other modules may have contributed to this.

Great to have additional info about xfstest there.

>
> Fixes: 69505fe98f19 ("fs/ntfs3: Replace inode_trylock with inode_lock")
> Reported-by: syzbot+a91fcdbd2698f99db8f4@syzkaller.appspotmail.com

Thanks for swapping out the reported-by!

> Suggested-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

LGTM so:

Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

> ---
>  fs/ntfs3/file.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
> index 65fb27d1e17c..2e321b84a1ed 100644
> --- a/fs/ntfs3/file.c
> +++ b/fs/ntfs3/file.c
> @@ -322,7 +322,10 @@ static int ntfs_file_mmap(struct file *file, struct vm_area_struct *vma)
>  		}
>
>  		if (ni->i_valid < to) {
> -			inode_lock(inode);
> +			if (!inode_trylock(inode)) {
> +				err = -EAGAIN;
> +				goto out;
> +			}
>  			err = ntfs_extend_initialized_size(file, ni,
>  							   ni->i_valid, to);
>  			inode_unlock(inode);
> --
> 2.43.0
>