From 29cb48594b873f6193d6327097e504bd3e2314de Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 9 Jun 2010 15:31:01 +0200 Subject: [PATCH] writeback: fix pin_sb_for_writeback We need to check for s_instances to make sure we don't bother working against a filesystem that is beeing unmounted, and we need to call put_super to make sure a superblock is freed when we race against umount. Also no need to keep sb_lock after we got a reference on it. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- fs/fs-writeback.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 3a066e91ec8d..0609607d3955 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -534,19 +534,21 @@ select_queue: static bool pin_sb_for_writeback(struct super_block *sb) { spin_lock(&sb_lock); + if (list_empty(&sb->s_instances)) { + spin_unlock(&sb_lock); + return false; + } + sb->s_count++; + spin_unlock(&sb_lock); + if (down_read_trylock(&sb->s_umount)) { - if (sb->s_root) { - spin_unlock(&sb_lock); + if (sb->s_root) return true; - } - /* - * umounted, drop rwsem again and fall through to failure - */ up_read(&sb->s_umount); } - sb->s_count--; - spin_unlock(&sb_lock); + + put_super(sb); return false; } -- 2.20.1