On Fri, May 19, 2023 at 8:59 PM Amir Goldstein <amir73il@xxxxxxxxx> wrote:
>
> Similar to update size/mtime at the end of fuse_perform_write(),
> we need to bump the attr version when we update the inode size.
>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/fuse/passthrough.c | 53 ++++++++++++++++++++++++++++++++++---------
> 1 file changed, 42 insertions(+), 11 deletions(-)
>
> diff --git a/fs/fuse/passthrough.c b/fs/fuse/passthrough.c
> index 10b370bcc423..8352d6b91e0e 100644
> --- a/fs/fuse/passthrough.c
> +++ b/fs/fuse/passthrough.c
> @@ -14,15 +14,42 @@ struct fuse_aio_req {
> struct kiocb *iocb_fuse;
> };
>
> -static void fuse_aio_cleanup_handler(struct fuse_aio_req *aio_req)
> +static void fuse_file_start_write(struct file *fuse_file,
> + struct file *backing_file,
> + loff_t pos, size_t count)
> +{
> + struct inode *inode = file_inode(fuse_file);
> + struct fuse_inode *fi = get_fuse_inode(inode);
> +
> + if (inode->i_size < pos + count)
> + set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
> +
> + file_start_write(backing_file);
> +}
> +
> +static void fuse_file_end_write(struct file *fuse_file,
> + struct file *backing_file,
> + loff_t pos, ssize_t res)
> +{
> + struct inode *inode = file_inode(fuse_file);
> + struct fuse_inode *fi = get_fuse_inode(inode);
> +
> + file_end_write(backing_file);
> +
> + fuse_write_update_attr(inode, pos, res);
Hi Amir,
This function(fuse_file_end_write) will execute in interrupt context, but
fuse_write_update_attr() uses fuse_inode->lock, this will cause soft lockup.
So we may have to change all the fuse_inode->lock usage to fixup this bug, but
I think this is one ugly resolution.
Or why should we do aio_clearup_handler()? What is the difference between
fuse_passthrough_write_iter() with ovl_write_iter()?
Thanks,
Tianci
> + clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
> +}
> +
> +static void fuse_aio_cleanup_handler(struct fuse_aio_req *aio_req, long res)
> {
> struct kiocb *iocb = &aio_req->iocb;
> struct kiocb *iocb_fuse = aio_req->iocb_fuse;
> + struct file *filp = iocb->ki_filp;
> + struct file *fuse_filp = iocb_fuse->ki_filp;
>
> if (iocb->ki_flags & IOCB_WRITE) {
> - __sb_writers_acquired(file_inode(iocb->ki_filp)->i_sb,
> - SB_FREEZE_WRITE);
> - file_end_write(iocb->ki_filp);
> + __sb_writers_acquired(file_inode(filp)->i_sb, SB_FREEZE_WRITE);
> + fuse_file_end_write(fuse_filp, filp, iocb->ki_pos, res);
> }
>
> iocb_fuse->ki_pos = iocb->ki_pos;
> @@ -35,7 +62,7 @@ static void fuse_aio_rw_complete(struct kiocb *iocb, long res)
> container_of(iocb, struct fuse_aio_req, iocb);
> struct kiocb *iocb_fuse = aio_req->iocb_fuse;
>
> - fuse_aio_cleanup_handler(aio_req);
> + fuse_aio_cleanup_handler(aio_req, res);
> iocb_fuse->ki_complete(iocb_fuse, res);
> }
>
> @@ -71,7 +98,7 @@ ssize_t fuse_passthrough_read_iter(struct kiocb *iocb_fuse,
> aio_req->iocb.ki_complete = fuse_aio_rw_complete;
> ret = call_read_iter(passthrough_filp, &aio_req->iocb, iter);
> if (ret != -EIOCBQUEUED)
> - fuse_aio_cleanup_handler(aio_req);
> + fuse_aio_cleanup_handler(aio_req, ret);
> }
> out:
> revert_creds(old_cred);
> @@ -87,22 +114,25 @@ ssize_t fuse_passthrough_write_iter(struct kiocb *iocb_fuse,
> struct inode *fuse_inode = file_inode(fuse_filp);
> struct file *passthrough_filp = ff->passthrough->filp;
> struct inode *passthrough_inode = file_inode(passthrough_filp);
> + size_t count = iov_iter_count(iter);
> const struct cred *old_cred;
> ssize_t ret;
> rwf_t rwf;
>
> - if (!iov_iter_count(iter))
> + if (!count)
> return 0;
>
> inode_lock(fuse_inode);
>
> old_cred = override_creds(ff->passthrough->cred);
> if (is_sync_kiocb(iocb_fuse)) {
> - file_start_write(passthrough_filp);
> + fuse_file_start_write(fuse_filp, passthrough_filp,
> + iocb_fuse->ki_pos, count);
> rwf = iocb_to_rw_flags(iocb_fuse->ki_flags, FUSE_IOCB_MASK);
> ret = vfs_iter_write(passthrough_filp, iter, &iocb_fuse->ki_pos,
> rwf);
> - file_end_write(passthrough_filp);
> + fuse_file_end_write(fuse_filp, passthrough_filp,
> + iocb_fuse->ki_pos, ret);
> } else {
> struct fuse_aio_req *aio_req;
>
> @@ -112,7 +142,8 @@ ssize_t fuse_passthrough_write_iter(struct kiocb *iocb_fuse,
> goto out;
> }
>
> - file_start_write(passthrough_filp);
> + fuse_file_start_write(fuse_filp, passthrough_filp,
> + iocb_fuse->ki_pos, count);
> __sb_writers_release(passthrough_inode->i_sb, SB_FREEZE_WRITE);
>
> aio_req->iocb_fuse = iocb_fuse;
> @@ -120,7 +151,7 @@ ssize_t fuse_passthrough_write_iter(struct kiocb *iocb_fuse,
> aio_req->iocb.ki_complete = fuse_aio_rw_complete;
> ret = call_write_iter(passthrough_filp, &aio_req->iocb, iter);
> if (ret != -EIOCBQUEUED)
> - fuse_aio_cleanup_handler(aio_req);
> + fuse_aio_cleanup_handler(aio_req, ret);
> }
> out:
> revert_creds(old_cred);
> --
> 2.34.1
>
