fuse: destroy bdi on umount

If a fuse filesystem is unmounted but the device file descriptor
remains open and a new mount reuses the old device number, then the
mount fails with EEXIST and the following warning is printed in the
kernel log:

  WARNING: at fs/sysfs/dir.c:462 sysfs_add_one+0x35/0x3d()
  sysfs: duplicate filename '0:15' can not be created

The cause is that the bdi belonging to the fuse filesystem was
destoryed only after the device file was released.  Fix this by
calling bdi_destroy() from fuse_put_super() instead.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@kernel.org

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index e0c7ada08a1fe6f3caed4b31dc81fbb4ae9e1984..c4a3d9bbdaa877f2a817045abddb3b94317124eb 100644 (file)
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -281,7 +281,8 @@ __releases(&fc->lock)
                        fc->blocked = 0;
                        wake_up_all(&fc->blocked_waitq);
                }
-               if (fc->num_background == FUSE_CONGESTION_THRESHOLD) {
+               if (fc->num_background == FUSE_CONGESTION_THRESHOLD &&
+                   fc->connected) {
                        clear_bdi_congested(&fc->bdi, READ);
                        clear_bdi_congested(&fc->bdi, WRITE);
                }

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index dc649f6bc3e577ee196093577898efdfa1a54382..459b73dd45e1302298ab75a5e6c4bee86849ebae 100644 (file)
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -292,6 +292,7 @@ static void fuse_put_super(struct super_block *sb)
        list_del(&fc->entry);
        fuse_ctl_remove_conn(fc);
        mutex_unlock(&fuse_mutex);
+       bdi_destroy(&fc->bdi);
        fuse_conn_put(fc);
 }
 
@@ -532,7 +533,6 @@ void fuse_conn_put(struct fuse_conn *fc)
                if (fc->destroy_req)
                        fuse_request_free(fc->destroy_req);
                mutex_destroy(&fc->inst_mutex);
-               bdi_destroy(&fc->bdi);
                fc->release(fc);
        }
 }