From: Zhang Qiang Date: Tue, 18 Aug 2009 06:58:24 +0000 (+0800) Subject: nilfs2: missing a read lock for segment writer in nilfs_attach_checkpoint() X-Git-Tag: v2.6.31-rc7~9^2~1 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=1154ecbd2f8298ef75609f5f8ed5aca96be599fb;p=linux.git nilfs2: missing a read lock for segment writer in nilfs_attach_checkpoint() 'ns_cno' of structure 'the_nilfs' must be protected from segment writer, in other words, the caller of nilfs_get_checkpoint should hold read lock for nilfs->ns_segctor_sem. This patch adds the lock/unlock operations in nilfs_attach_checkpoint() when calling nilfs_cpfile_get_checkpoint(). Signed-off-by: Zhang Qiang Signed-off-by: Ryusuke Konishi --- diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c index 8e2ec43b18f4..151964f0de4c 100644 --- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -416,8 +416,10 @@ int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno) if (unlikely(err)) goto failed; + down_read(&nilfs->ns_segctor_sem); err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp, &bh_cp); + up_read(&nilfs->ns_segctor_sem); if (unlikely(err)) { if (err == -ENOENT || err == -EINVAL) { printk(KERN_ERR