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From: Benjamin Coddington <bcodding@redhat.com>
To: trond.myklebust@hammerspace.com,
	anna@kernel.org
Cc: linux-nfs@vger.kernel.org
Subject: [PATCH 2/2] pnfs/blocklayout: Don't add zero-length pnfs_block_dev
Date: Tue,  5 Dec 2023 10:05:02 -0500
Message-ID: <53e2ab90d83d4cdc15f1b48b2eb671ad26f54a6a.1701788600.git.bcodding@redhat.com>
In-Reply-To: <33e0ddfaad92ca5d6b0a4d1cc7541cf5a7480d7a.1701788600.git.bcodding@redhat.com>
References: <33e0ddfaad92ca5d6b0a4d1cc7541cf5a7480d7a.1701788600.git.bcodding@redhat.com>
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We noticed a SCSI device that refused to allow READ CAPACITY when the
device had a PR with exclusive access, registrants only.  The result of
this situation is that the blocklayout driver adds a pnfs_block_dev of zero
length which always fails the offset_in_map tests.  Instead of continuously
trying to do pNFS for this case, just mark the device as unavailable which
will allow the client to fallback to the MDS for the duration of
PNFS_DEVICE_RETRY_TIMEOUT.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
 fs/nfs/blocklayout/dev.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/nfs/blocklayout/dev.c b/fs/nfs/blocklayout/dev.c
index f318a05a80e1..c97ebc42ec0f 100644
--- a/fs/nfs/blocklayout/dev.c
+++ b/fs/nfs/blocklayout/dev.c
@@ -351,6 +351,9 @@ bl_parse_scsi(struct nfs_server *server, struct pnfs_block_dev *d,
 	d->map = bl_map_simple;
 	d->pr_key = v->scsi.pr_key;
 
+	if (d->len == 0)
+		return -ENODEV;
+
 	pr_info("pNFS: using block device %s (reservation key 0x%llx)\n",
 		d->bdev_handle->bdev->bd_disk->disk_name, d->pr_key);
 
-- 
2.43.0