From f6a1bb6de4548575400352a9eb1b8be1f244b91f Mon Sep 17 00:00:00 2001 From: Benjamin Coddington Date: Fri, 22 Nov 2024 10:11:12 -0500 Subject: [PATCH] nfs/blocklayout: Limit repeat device registration on failure [ Upstream commit 614733f9441ed53bb442d4734112ec1e24bd6da7 ] Every pNFS SCSI IO wants to do LAYOUTGET, then within the layout find the device which can drive GETDEVINFO, then finally may need to prep the device with a reservation. This slow work makes a mess of IO latencies if one of the later steps is going to fail for awhile. If we're unable to register a SCSI device, ensure we mark the device as unavailable so that it will timeout and be re-added via GETDEVINFO. This avoids repeated doomed attempts to register a device in the IO path. Add some clarifying comments as well. Fixes: d869da91cccb ("nfs/blocklayout: Fix premature PR key unregistration") Signed-off-by: Benjamin Coddington Reviewed-by: Christoph Hellwig Reviewed-by: Chuck Lever Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin --- fs/nfs/blocklayout/blocklayout.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c index 0becdec12970..47189476b553 100644 --- a/fs/nfs/blocklayout/blocklayout.c +++ b/fs/nfs/blocklayout/blocklayout.c @@ -571,19 +571,32 @@ retry: if (!node) return ERR_PTR(-ENODEV); + /* + * Devices that are marked unavailable are left in the cache with a + * timeout to avoid sending GETDEVINFO after every LAYOUTGET, or + * constantly attempting to register the device. Once marked as + * unavailable they must be deleted and never reused. + */ if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) { unsigned long end = jiffies; unsigned long start = end - PNFS_DEVICE_RETRY_TIMEOUT; if (!time_in_range(node->timestamp_unavailable, start, end)) { + /* Uncork subsequent GETDEVINFO operations for this device */ nfs4_delete_deviceid(node->ld, node->nfs_client, id); goto retry; } goto out_put; } - if (!bl_register_dev(container_of(node, struct pnfs_block_dev, node))) + if (!bl_register_dev(container_of(node, struct pnfs_block_dev, node))) { + /* + * If we cannot register, treat this device as transient: + * Make a negative cache entry for the device + */ + nfs4_mark_deviceid_unavailable(node); goto out_put; + } return node; -- 2.39.5