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authorTejun Heo <tj@kernel.org>2014-02-03 20:02:57 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-02-08 00:42:40 +0100
commitccf02aaf8167bb8bfb3c17c01c843d309b872671 (patch)
tree744c59c27e0883dca4da631118432a8df86ce894 /fs/kernfs/dir.c
parentkernfs: restructure removal path to fix possible premature return (diff)
downloadlinux-ccf02aaf8167bb8bfb3c17c01c843d309b872671.tar.xz
linux-ccf02aaf8167bb8bfb3c17c01c843d309b872671.zip
kernfs: invoke kernfs_unmap_bin_file() directly from kernfs_deactivate()
kernfs_unmap_bin_file() is supposed to unmap all memory mappings of the target file before kernfs_remove() finishes; however, it currently is being called from kernfs_addrm_finish() and has the same race problem as the original implementation of deactivation when there are multiple removers - only the remover which snatches the node to its addrm_cxt->removed list is guaranteed to wait for its completion before returning. It can be easily fixed by moving kernfs_unmap_bin_file() invocation from kernfs_addrm_finish() to kernfs_deactivated(). The function may be called multiple times but that shouldn't do any harm. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/kernfs/dir.c')
-rw-r--r--fs/kernfs/dir.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 3ac93737174a..9603c06550a0 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -177,9 +177,10 @@ void kernfs_put_active(struct kernfs_node *kn)
* kernfs_deactivate - deactivate kernfs_node
* @kn: kernfs_node to deactivate
*
- * Deny new active references and drain existing ones. Mutiple
- * removers may invoke this function concurrently on @kn and all will
- * return after deactivation and draining are complete.
+ * Deny new active references, drain existing ones and nuke all
+ * existing mmaps. Mutiple removers may invoke this function
+ * concurrently on @kn and all will return after deactivation and
+ * draining are complete.
*/
static void kernfs_deactivate(struct kernfs_node *kn)
__releases(&kernfs_mutex) __acquires(&kernfs_mutex)
@@ -213,6 +214,8 @@ static void kernfs_deactivate(struct kernfs_node *kn)
rwsem_release(&kn->dep_map, 1, _RET_IP_);
}
+ kernfs_unmap_bin_file(kn);
+
mutex_lock(&kernfs_mutex);
}
@@ -493,7 +496,6 @@ void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt)
acxt->removed = kn->u.removed_list;
- kernfs_unmap_bin_file(kn);
kernfs_put(kn);
}
}