Commit bf1c6aca authored by Sage Weil's avatar Sage Weil
Browse files

ceph: protect d_parent access in ceph_d_revalidate 



Protect d_parent with d_lock.  Carry a reference.  Simplify the flow so
that there is a single exit point and cleanup.

Reviewed-by: default avatarYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent 5f21c96d

fs/ceph/dir.c

+17 −15
Original line number Diff line number Diff line
@@ -1024,36 +1024,38 @@ static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry) 
 */

static int ceph_d_revalidate(struct dentry *dentry, struct nameidata *nd)

{

	int valid = 0;

	struct inode *dir;



	if (nd && nd->flags & LOOKUP_RCU)

		return -ECHILD;



	dir = dentry->d_parent->d_inode;



	dout("d_revalidate %p '%.*s' inode %p offset %lld\n", dentry,

	     dentry->d_name.len, dentry->d_name.name, dentry->d_inode,

	     ceph_dentry(dentry)->offset);



	dir = ceph_get_dentry_parent_inode(dentry);



	/* always trust cached snapped dentries, snapdir dentry */

	if (ceph_snap(dir) != CEPH_NOSNAP) {

		dout("d_revalidate %p '%.*s' inode %p is SNAPPED\n", dentry,

		     dentry->d_name.len, dentry->d_name.name, dentry->d_inode);

		goto out_touch;

		valid = 1;

	} else if (dentry->d_inode &&

		   ceph_snap(dentry->d_inode) == CEPH_SNAPDIR) {

		valid = 1;

	} else if (dentry_lease_is_valid(dentry) ||

		   dir_lease_is_valid(dir, dentry)) {

		valid = 1;

	}

	if (dentry->d_inode && ceph_snap(dentry->d_inode) == CEPH_SNAPDIR)

		goto out_touch;



	if (dentry_lease_is_valid(dentry) ||

	    dir_lease_is_valid(dir, dentry))

		goto out_touch;



	dout("d_revalidate %p invalid\n", dentry);

	d_drop(dentry);

	return 0;

out_touch:

	dout("d_revalidate %p %s\n", dentry, valid ? "valid" : "invalid");

	if (valid)

		ceph_dentry_lru_touch(dentry);

	return 1;

	else

		d_drop(dentry);

	iput(dir);

	return valid;

}



/*