From: Yan, Zheng <zyan@redhat.com>
Date: Wed, 22 May 2019 09:26:27 +0000 (+0800)
Subject: ceph: fix dir_lease_is_valid()
X-Git-Tag: v5.3-rc1~43^2~60
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=feab6ac25dbfe3ab96299cb741925dc8d2da0caf;p=linux.git

ceph: fix dir_lease_is_valid()

It should call __ceph_dentry_dir_lease_touch() under dentry->d_lock.
Besides, ceph_dentry(dentry) can be NULL when called by LOOKUP_RCU
d_revalidate()

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---

diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 0637149fb9f9..1271024a3797 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -1512,18 +1512,26 @@ static int __dir_lease_try_check(const struct dentry *dentry)
 static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry)
 {
 	struct ceph_inode_info *ci = ceph_inode(dir);
-	struct ceph_dentry_info *di = ceph_dentry(dentry);
-	int valid = 0;
+	int valid;
+	int shared_gen;
 
 	spin_lock(&ci->i_ceph_lock);
-	if (atomic_read(&ci->i_shared_gen) == di->lease_shared_gen)
-		valid = __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1);
+	valid = __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1);
+	shared_gen = atomic_read(&ci->i_shared_gen);
 	spin_unlock(&ci->i_ceph_lock);
-	if (valid)
-		__ceph_dentry_dir_lease_touch(di);
-	dout("dir_lease_is_valid dir %p v%u dentry %p v%u = %d\n",
-	     dir, (unsigned)atomic_read(&ci->i_shared_gen),
-	     dentry, (unsigned)di->lease_shared_gen, valid);
+	if (valid) {
+		struct ceph_dentry_info *di;
+		spin_lock(&dentry->d_lock);
+		di = ceph_dentry(dentry);
+		if (dir == d_inode(dentry->d_parent) &&
+		    di && di->lease_shared_gen == shared_gen)
+			__ceph_dentry_dir_lease_touch(di);
+		else
+			valid = 0;
+		spin_unlock(&dentry->d_lock);
+	}
+	dout("dir_lease_is_valid dir %p v%u dentry %p = %d\n",
+	     dir, (unsigned)atomic_read(&ci->i_shared_gen), dentry, valid);
 	return valid;
 }