nfs/blocklayout: support RH/Fedora dm-mpath device nodes
Instead of reusing the wwn-* names for multipath devices nodes RHEL and
Fedora introduce new dm-mpath-uuid-* nodes with a slightly different
naming scheme. Try these names first to ensure we always get a
multipath-capable device if it exists.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/blocklayout/dev.c b/fs/nfs/blocklayout/dev.c
index ea70883..436bb30 100644
--- a/fs/nfs/blocklayout/dev.c
+++ b/fs/nfs/blocklayout/dev.c
@@ -312,6 +312,28 @@
return bdev;
}
+/*
+ * Try to open the RH/Fedora specific dm-mpath udev path for this WWN, as the
+ * wwn- links will only point to the first discovered SCSI device there.
+ */
+static struct block_device *
+bl_open_dm_mpath_udev_path(struct pnfs_block_volume *v)
+{
+ struct block_device *bdev;
+ const char *devname;
+
+ devname = kasprintf(GFP_KERNEL,
+ "/dev/disk/by-id/dm-uuid-mpath-%d%*phN",
+ v->scsi.designator_type,
+ v->scsi.designator_len, v->scsi.designator);
+ if (!devname)
+ return ERR_PTR(-ENOMEM);
+
+ bdev = blkdev_get_by_path(devname, FMODE_READ | FMODE_WRITE, NULL);
+ kfree(devname);
+ return bdev;
+}
+
static int
bl_parse_scsi(struct nfs_server *server, struct pnfs_block_dev *d,
struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
@@ -323,7 +345,9 @@
if (!bl_validate_designator(v))
return -EINVAL;
- d->bdev = bl_open_udev_path(v);
+ d->bdev = bl_open_dm_mpath_udev_path(v);
+ if (IS_ERR(d->bdev))
+ d->bdev = bl_open_udev_path(v);
if (IS_ERR(d->bdev))
return PTR_ERR(d->bdev);