Re: [PATCH v2 1/4] nfs/blocklayout: Fix premature PR key unregistration

Chuck Lever
2024-06-24T15:08:30Z

On Sun, Jun 23, 2024 at 09:36:27AM +0200, Christoph Hellwig wrote:
> On Sat, Jun 22, 2024 at 01:26:10PM -0400, Chuck Lever wrote:
> > This patch currently adds the pr_reg callback to
> > bl_find_get_deviceid(), which has no visibility of the volume
> > hierarchy. Where should the registration be done instead? I'm
> > missing something.
>
> Something like the patch below (untested Sunday morning coding) should
> do the trick:
>
> diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
> index 947b2c52344097..6db54b215066e0 100644
> --- a/fs/nfs/blocklayout/blocklayout.c
> +++ b/fs/nfs/blocklayout/blocklayout.c
> @@ -564,34 +564,32 @@ bl_find_get_deviceid(struct nfs_server *server,
> gfp_t gfp_mask)
> {
> struct nfs4_deviceid_node *node;
> - struct pnfs_block_dev *d;
> - unsigned long start, end;
> + int err = -ENODEV;
>
> retry:
> node = nfs4_find_get_deviceid(server, id, cred, gfp_mask);
> if (!node)
> return ERR_PTR(-ENODEV);
>
> - if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags))
> - goto transient;
> + if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
> + unsigned long end = jiffies;
> + unsigned long start = end - PNFS_DEVICE_RETRY_TIMEOUT;
>
> - d = container_of(node, struct pnfs_block_dev, node);
> - if (d->pr_register)
> - if (!d->pr_register(d))
> - goto out_put;
> - return node;
> -
> -transient:
> - end = jiffies;
> - start = end - PNFS_DEVICE_RETRY_TIMEOUT;
> - if (!time_in_range(node->timestamp_unavailable, start, end)) {
> - nfs4_delete_deviceid(node->ld, node->nfs_client, id);
> - goto retry;
> + if (!time_in_range(node->timestamp_unavailable, start, end)) {
> + nfs4_delete_deviceid(node->ld, node->nfs_client, id);
> + goto retry;
> + }
> + goto out_put;
> }
>
> + err = bl_register_dev(container_of(node, struct pnfs_block_dev, node));
> + if (err)
> + goto out_put;
> + return node;
> +
> out_put:
> nfs4_put_deviceid_node(node);
> - return ERR_PTR(-ENODEV);
> + return ERR_PTR(err);
> }
>
> static int
> diff --git a/fs/nfs/blocklayout/blocklayout.h b/fs/nfs/blocklayout/blocklayout.h
> index cc788e8ce90933..7efbef9d10dba8 100644
> --- a/fs/nfs/blocklayout/blocklayout.h
> +++ b/fs/nfs/blocklayout/blocklayout.h
> @@ -104,6 +104,7 @@ struct pnfs_block_dev {
> u64 start;
> u64 len;
>
> + enum pnfs_block_volume_type type;
> u32 nr_children;
> struct pnfs_block_dev *children;
> u64 chunk_size;
> @@ -116,7 +117,6 @@ struct pnfs_block_dev {
>
> bool (*map)(struct pnfs_block_dev *dev, u64 offset,
> struct pnfs_block_dev_map *map);
> - bool (*pr_register)(struct pnfs_block_dev *dev);
> };
>
> /* pnfs_block_dev flag bits */
> @@ -178,6 +178,7 @@ struct bl_msg_hdr {
> #define BL_DEVICE_REQUEST_ERR 0x2 /* User level process fails */
>
> /* dev.c */
> +int bl_register_dev(struct pnfs_block_dev *d);
> struct nfs4_deviceid_node *bl_alloc_deviceid_node(struct nfs_server *server,
> struct pnfs_device *pdev, gfp_t gfp_mask);
> void bl_free_deviceid_node(struct nfs4_deviceid_node *d);
> diff --git a/fs/nfs/blocklayout/dev.c b/fs/nfs/blocklayout/dev.c
> index 16fb64d4af31db..72e061e87e145a 100644
> --- a/fs/nfs/blocklayout/dev.c
> +++ b/fs/nfs/blocklayout/dev.c
> @@ -13,9 +13,74 @@
>
> #define NFSDBG_FACILITY NFSDBG_PNFS_LD
>
> +static void bl_unregister_scsi(struct pnfs_block_dev *dev)
> +{
> + struct block_device *bdev = file_bdev(dev->bdev_file);
> + const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
> +
> + if (!test_and_clear_bit(PNFS_BDEV_REGISTERED, &dev->flags))
> + return;
> +
> + if (ops->pr_register(bdev, dev->pr_key, 0, false))
> + pr_err("failed to unregister PR key.\n");
> +}
> +
> +static bool bl_register_scsi(struct pnfs_block_dev *dev)
> +{
> + struct block_device *bdev = file_bdev(dev->bdev_file);
> + const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
> + int status;
> +
> + if (test_and_set_bit(PNFS_BDEV_REGISTERED, &dev->flags))
> + return true;
> +
> + status = ops->pr_register(bdev, 0, dev->pr_key, true);
> + if (status) {
> + pr_err("pNFS: failed to register key for block device %s.",
> + bdev->bd_disk->disk_name);
> + return false;
> + }
> + return true;
> +}
> +
> +static void bl_unregister_dev(struct pnfs_block_dev *dev)
> +{
> + if (dev->nr_children) {
> + for (u32 i = 0; i < dev->nr_children; i++)
> + bl_unregister_dev(&dev->children[i]);
> + return;
> + }
> +
> + if (dev->type == PNFS_BLOCK_VOLUME_SCSI)
> + bl_unregister_scsi(dev);
> +}
> +
> +int bl_register_dev(struct pnfs_block_dev *dev)
> +{
> + if (dev->nr_children) {
> + for (u32 i = 0; i < dev->nr_children; i++) {
> + int ret = bl_register_dev(&dev->children[i]);
> +
> + if (ret) {
> + while (i > 0)
> + bl_unregister_dev(&dev->children[--i]);
> + return ret;
> + }
> + }
> +
> + return 0;
> + }
> +
> + if (dev->type == PNFS_BLOCK_VOLUME_SCSI)
> + return bl_register_scsi(dev);
> + return 0;
> +}
> +
> static void
> bl_free_device(struct pnfs_block_dev *dev)
> {
> + bl_unregister_dev(dev);
> +
> if (dev->nr_children) {
> int i;
>
> @@ -23,17 +88,6 @@ bl_free_device(struct pnfs_block_dev *dev)
> bl_free_device(&dev->children[i]);
> kfree(dev->children);
> } else {
> - if (test_and_clear_bit(PNFS_BDEV_REGISTERED, &dev->flags)) {
> - struct block_device *bdev = file_bdev(dev->bdev_file);
> - const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
> - int error;
> -
> - error = ops->pr_register(file_bdev(dev->bdev_file),
> - dev->pr_key, 0, false);
> - if (error)
> - pr_err("failed to unregister PR key.\n");
> - }
> -
> if (dev->bdev_file)
> fput(dev->bdev_file);
> }
> @@ -226,30 +280,6 @@ static bool bl_map_stripe(struct pnfs_block_dev *dev, u64 offset,
> return true;
> }
>
> -/**
> - * bl_pr_register_scsi - Register a SCSI PR key for @d
> - * @dev: pNFS block device, key to register is already in @d->pr_key
> - *
> - * Returns true if the device's PR key is registered, otherwise false.
> - */
> -static bool bl_pr_register_scsi(struct pnfs_block_dev *dev)
> -{
> - struct block_device *bdev = file_bdev(dev->bdev_file);
> - const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
> - int status;
> -
> - if (test_and_set_bit(PNFS_BDEV_REGISTERED, &dev->flags))
> - return true;
> -
> - status = ops->pr_register(bdev, 0, dev->pr_key, true);
> - if (status) {
> - pr_err("pNFS: failed to register key for block device %s.",
> - bdev->bd_disk->disk_name);
> - return false;
> - }
> - return true;
> -}
> -
> static int
> bl_parse_deviceid(struct nfs_server *server, struct pnfs_block_dev *d,
> struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask);
> @@ -392,7 +422,6 @@ bl_parse_scsi(struct nfs_server *server, struct pnfs_block_dev *d,
> goto out_blkdev_put;
> }
>
> - d->pr_register = bl_pr_register_scsi;
> return 0;
>
> out_blkdev_put:
> @@ -478,7 +507,9 @@ static int
> bl_parse_deviceid(struct nfs_server *server, struct pnfs_block_dev *d,
> struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
> {
> - switch (volumes[idx].type) {
> + d->type = volumes[idx].type;
> +
> + switch (d->type) {
> case PNFS_BLOCK_VOLUME_SIMPLE:
> return bl_parse_simple(server, d, volumes, idx, gfp_mask);
> case PNFS_BLOCK_VOLUME_SLICE:
> @@ -490,7 +521,7 @@ bl_parse_deviceid(struct nfs_server *server, struct pnfs_block_dev *d,
> case PNFS_BLOCK_VOLUME_SCSI:
> return bl_parse_scsi(server, d, volumes, idx, gfp_mask);
> default:
> - dprintk("unsupported volume type: %d\n", volumes[idx].type);
> + dprintk("unsupported volume type: %d\n", d->type);
> return -EIO;
> }
> }

Thanks. I've applied this as a separate patch (I can squash it into
1/4 once it passes testing). The first write I/O segfaults at L143
in do_add_page_to_bio() :

142 if (!offset_in_map(disk_addr, map)) {
143 if (!dev->map(dev, disk_addr, map) || !offset_in_map(disk_addr, map))
144 return ERR_PTR(-EIO);

I'm looking into it.

--
Chuck Lever