This patch allows path errors from the multipath ctr function to
propagate up to userspace as errno values from the ioctl() call.

This is in response to
https://www.redhat.com/archives/dm-devel/2008-May/msg00000.html
and
https://bugzilla.redhat.com/show_bug.cgi?id=444421

The patch only lets through the errors that it needs to, in order to
get the path errors from parse_path(). It's possible that there are
other errors worth progatating that this leaves out.

The patch was built against the 2.6.26-rc3 kernel.

-Ben

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
dm-mpath.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)

Index: linux-2.6.25.i686/drivers/md/dm-mpath.c
================================================== =================
--- linux-2.6.25.i686.orig/drivers/md/dm-mpath.c
+++ linux-2.6.25.i686/drivers/md/dm-mpath.c
@@ -555,12 +555,12 @@ static struct pgpath *parse_path(struct
/* we need at least a path arg */
if (as->argc < 1) {
ti->error = "no device given";
- return NULL;
+ return ERR_PTR(-EINVAL);
}

p = alloc_pgpath();
if (!p)
- return NULL;
+ return ERR_PTR(-ENOMEM);

r = dm_get_device(ti, shift(as), ti->begin, ti->len,
dm_table_get_mode(ti->table), &p->path.dev);
@@ -579,7 +579,7 @@ static struct pgpath *parse_path(struct

bad:
free_pgpath(p);
- return NULL;
+ return ERR_PTR(r);
}

static struct priority_group *parse_priority_group(struct arg_set *as,
@@ -598,13 +598,13 @@ static struct priority_group *parse_prio
if (as->argc < 2) {
as->argc = 0;
ti->error = "not enough priority group aruments";
- return NULL;
+ return ERR_PTR(-EINVAL);
}

pg = alloc_priority_group();
if (!pg) {
ti->error = "couldn't allocate priority group";
- return NULL;
+ return ERR_PTR(-ENOMEM);
}
pg->m = m;

@@ -635,8 +635,10 @@ static struct priority_group *parse_prio
path_args.argv = as->argv;

pgpath = parse_path(&path_args, &pg->ps, ti);
- if (!pgpath)
+ if (IS_ERR(pgpath)){
+ r = PTR_ERR(pgpath);
goto bad;
+ }

pgpath->pg = pg;
list_add_tail(&pgpath->list, &pg->pgpaths);
@@ -647,7 +649,7 @@ static struct priority_group *parse_prio

bad:
free_priority_group(pg, ti);
- return NULL;
+ return ERR_PTR(r);
}

static int parse_hw_handler(struct arg_set *as, struct multipath *m)
@@ -778,8 +780,8 @@ static int multipath_ctr(struct dm_targe
struct priority_group *pg;

pg = parse_priority_group(&as, m);
- if (!pg) {
- r = -EINVAL;
+ if (IS_ERR(pg)) {
+ r = PTR_ERR(pg);
goto bad;
}


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