fuseblk: Fix warning in super_setup_bdi_name()

Commit 5f7f7543f52e "fuse: Convert to separately allocated bdi" didn't
properly handle fuseblk filesystem. When fuse_bdi_init() is called for
that filesystem type, sb->s_bdi is already initialized (by
set_bdev_super()) to point to block device's bdi and consequently
super_setup_bdi_name() complains about this fact when reseting bdi to
the private one.

Fix the problem by properly dropping bdi reference in fuse_bdi_init()
before creating a private bdi in super_setup_bdi_name().

Fixes: 5f7f7543f52e ("fuse: Convert to separately allocated bdi")
Reported-by: Rakesh Pandit <rakesh@tuxera.com>
Tested-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 73cf051352521ad400af30befd3afbd2fc595c31..9da1a61276d199545a3863f9479e849ff48fe70b 100644 (file)
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -972,8 +972,15 @@ static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
        int err;
        char *suffix = "";
 
-       if (sb->s_bdev)
+       if (sb->s_bdev) {
                suffix = "-fuseblk";
+               /*
+                * sb->s_bdi points to blkdev's bdi however we want to redirect
+                * it to our private bdi...
+                */
+               bdi_put(sb->s_bdi);
+               sb->s_bdi = &noop_backing_dev_info;
+       }
        err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
                                   MINOR(fc->dev), suffix);
        if (err)