> @@ -1892,6 +1893,8 @@ xfs_free_buftarg(
> list_lru_destroy(&btp->bt_lru);
>
> blkdev_issue_flush(btp->bt_bdev);
> + if (btp->bt_daxdev)
> + dax_unregister_holder(btp->bt_daxdev, btp->bt_mount);
> fs_put_dax(btp->bt_daxdev);
>
> kmem_free(btp);
> @@ -1939,6 +1942,7 @@ xfs_alloc_buftarg(
> struct block_device *bdev)
> {
> xfs_buftarg_t *btp;
> + int error;
>
> btp = kmem_zalloc(sizeof(*btp), KM_NOFS);
>
> @@ -1946,6 +1950,14 @@ xfs_alloc_buftarg(
> btp->bt_dev = bdev->bd_dev;
> btp->bt_bdev = bdev;
> btp->bt_daxdev = fs_dax_get_by_bdev(bdev, &btp->bt_dax_part_off);
> + if (btp->bt_daxdev) {
> + error = dax_register_holder(btp->bt_daxdev, mp,
> + &xfs_dax_holder_operations);
> + if (error) {
> + xfs_err(mp, "DAX device already in use?!");
> + goto error_free;
> + }
> + }
It seems to me that just passing the holder and holder ops to
fs_dax_get_by_bdev and the holder to dax_unregister_holder would
significantly simply the interface here.
Dan, what do you think?
> +#if IS_ENABLED(CONFIG_MEMORY_FAILURE) && IS_ENABLED(CONFIG_FS_DAX)
No real need for the IS_ENABLED. Also any reason to even build this
file if the options are not set? It seems like
xfs_dax_holder_operations should just be defined to NULL and the
whole file not supported if we can't support the functionality.
Dan: not for this series, but is there any reason not to require
MEMORY_FAILURE for DAX to start with?
> +
> + ddev_start = mp->m_ddev_targp->bt_dax_part_off;
> + ddev_end = ddev_start +
> + (mp->m_ddev_targp->bt_bdev->bd_nr_sectors << SECTOR_SHIFT) - 1;
This should use bdev_nr_bytes.
But didn't we say we don't want to support notifications on partitioned
devices and thus don't actually need all this?
> +
> + /* Ignore the range out of filesystem area */
> + if ((offset + len) < ddev_start)
No need for the inner braces.
> + if ((offset + len) > ddev_end)
No need for the braces either.
> diff --git a/fs/xfs/xfs_notify_failure.h b/fs/xfs/xfs_notify_failure.h
> new file mode 100644
> index 000000000000..76187b9620f9
> --- /dev/null
> +++ b/fs/xfs/xfs_notify_failure.h
> @@ -0,0 +1,10 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2022 Fujitsu. All Rights Reserved.
> + */
> +#ifndef __XFS_NOTIFY_FAILURE_H__
> +#define __XFS_NOTIFY_FAILURE_H__
> +
> +extern const struct dax_holder_operations xfs_dax_holder_operations;
> +
> +#endif /* __XFS_NOTIFY_FAILURE_H__ */
Dowe really need a new header for this vs just sequeezing it into
xfs_super.h or something like that?
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index e8f37bdc8354..b8de6ed2c888 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -353,6 +353,12 @@ xfs_setup_dax_always(
> return -EINVAL;
> }
>
> + if (xfs_has_reflink(mp) && !xfs_has_rmapbt(mp)) {
> + xfs_alert(mp,
> + "need rmapbt when both DAX and reflink enabled.");
> + return -EINVAL;
> + }
Right now we can't even enable reflink with DAX yet, so adding this
here seems premature - it should go into the patch allowing DAX+reflink.
