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-rw-r--r--fs/afs/vl_alias.c90
1 files changed, 89 insertions, 1 deletions
diff --git a/fs/afs/vl_alias.c b/fs/afs/vl_alias.c
index d1d91a25fbe0..76bfa4dde4a4 100644
--- a/fs/afs/vl_alias.c
+++ b/fs/afs/vl_alias.c
@@ -180,6 +180,94 @@ is_alias:
return 1;
}
+/*
+ * Query the new cell for a volume from a cell we're already using.
+ */
+static int afs_query_for_alias_one(struct afs_cell *cell, struct key *key,
+ struct afs_cell *p)
+{
+ struct afs_volume *volume, *pvol = NULL;
+ int ret;
+
+ /* Arbitrarily pick the first volume in the list. */
+ read_lock(&p->proc_lock);
+ if (!list_empty(&p->proc_volumes))
+ pvol = afs_get_volume(list_first_entry(&p->proc_volumes,
+ struct afs_volume, proc_link));
+ read_unlock(&p->proc_lock);
+ if (!pvol)
+ return 0;
+
+ _enter("%s:%s", cell->name, pvol->name);
+
+ /* And see if it's in the new cell. */
+ volume = afs_sample_volume(cell, key, pvol->name, pvol->name_len);
+ if (IS_ERR(volume)) {
+ afs_put_volume(cell->net, pvol);
+ if (PTR_ERR(volume) != -ENOMEDIUM)
+ return PTR_ERR(volume);
+ /* That volume is not in the new cell, so not an alias */
+ return 0;
+ }
+
+ /* The new cell has a like-named volume also - compare volume ID,
+ * server and address lists.
+ */
+ ret = 0;
+ if (pvol->vid == volume->vid) {
+ rcu_read_lock();
+ if (afs_compare_volume_slists(volume, pvol))
+ ret = 1;
+ rcu_read_unlock();
+ }
+
+ afs_put_volume(cell->net, volume);
+ afs_put_volume(cell->net, pvol);
+ return ret;
+}
+
+/*
+ * Query the new cell for volumes we know exist in cells we're already using.
+ */
+static int afs_query_for_alias(struct afs_cell *cell, struct key *key)
+{
+ struct afs_cell *p;
+
+ _enter("%s", cell->name);
+
+ if (mutex_lock_interruptible(&cell->net->proc_cells_lock) < 0)
+ return -ERESTARTSYS;
+
+ hlist_for_each_entry(p, &cell->net->proc_cells, proc_link) {
+ if (p == cell || p->alias_of)
+ continue;
+ if (list_empty(&p->proc_volumes))
+ continue;
+ if (p->root_volume)
+ continue; /* Ignore cells that have a root.cell volume. */
+ afs_get_cell(p);
+ mutex_unlock(&cell->net->proc_cells_lock);
+
+ if (afs_query_for_alias_one(cell, key, p) != 0)
+ goto is_alias;
+
+ if (mutex_lock_interruptible(&cell->net->proc_cells_lock) < 0) {
+ afs_put_cell(cell->net, p);
+ return -ERESTARTSYS;
+ }
+
+ afs_put_cell(cell->net, p);
+ }
+
+ mutex_unlock(&cell->net->proc_cells_lock);
+ _leave(" = 0");
+ return 0;
+
+is_alias:
+ cell->alias_of = p; /* Transfer our ref */
+ return 1;
+}
+
static int afs_do_cell_detect_alias(struct afs_cell *cell, struct key *key)
{
struct afs_volume *root_volume;
@@ -199,7 +287,7 @@ static int afs_do_cell_detect_alias(struct afs_cell *cell, struct key *key)
/* Okay, this cell doesn't have an root.cell volume. We need to
* locate some other random volume and use that to check.
*/
- return -ENOMEDIUM;
+ return afs_query_for_alias(cell, key);
}
/*