Hey Christoph,
On 8 Jul 2016, at 5:41, Christoph Hellwig wrote:
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@xxxxxx>
---
fs/nfs/blocklayout/dev.c | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
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 @@ bl_open_udev_path(struct pnfs_block_volume *v)
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 @@ bl_parse_scsi(struct nfs_server *server, struct
pnfs_block_dev *d,
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);
Not a problem with this exact patch, but related.. If ->bdev isn't NULL
in
the error path, won't we try to do bdev_put in bl_free_device()? Should
we
do something like:
diff --git a/fs/nfs/blocklayout/dev.c b/fs/nfs/blocklayout/dev.c
index 436bb303d856..6d5e8428b074 100644
--- a/fs/nfs/blocklayout/dev.c
+++ b/fs/nfs/blocklayout/dev.c
@@ -33,7 +33,7 @@ bl_free_device(struct pnfs_block_dev *dev)
pr_err("failed to unregister PR
key.\n");
}
- if (dev->bdev)
+ if (!IS_ERR_OR_NULL(dev->bdev))
blkdev_put(dev->bdev, FMODE_READ |
FMODE_WRITE);
}
}
Ben
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