afs: prevent double cell registration
kafs doesn't check if the cell already exists - so if you do an echo "add
newcell.org 1.2.3.4" >/proc/fs/afs/cells it will try to create this cell
again. kobject will also complain about a double registration. To prevent
such problems, return -EEXIST in that case.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index 970d38f..788865d 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -127,14 +127,20 @@
_enter("%s,%s", name, vllist);
+ down_write(&afs_cells_sem);
+ read_lock(&afs_cells_lock);
+ list_for_each_entry(cell, &afs_cells, link) {
+ if (strcasecmp(cell->name, name) == 0)
+ goto duplicate_name;
+ }
+ read_unlock(&afs_cells_lock);
+
cell = afs_cell_alloc(name, vllist);
if (IS_ERR(cell)) {
_leave(" = %ld", PTR_ERR(cell));
return cell;
}
- down_write(&afs_cells_sem);
-
/* add a proc directory for this cell */
ret = afs_proc_cell_setup(cell);
if (ret < 0)
@@ -167,6 +173,11 @@
kfree(cell);
_leave(" = %d", ret);
return ERR_PTR(ret);
+
+duplicate_name:
+ read_unlock(&afs_cells_lock);
+ up_write(&afs_cells_sem);
+ return ERR_PTR(-EEXIST);
}
/*