Commit f5d55f03 authored by Jeff Layton's avatar Jeff Layton Committed by Ilya Dryomov
Browse files

ceph: vet the target and parent inodes before updating dentry lease 



In a later patch, we're going to need to allow ceph_fill_trace to
update the dentry's lease when the parent is not locked. This is
potentially racy though -- by the time we get around to processing the
trace, the parent may have already changed.

Change update_dentry_lease to take a ceph_vino pointer and use that to
ensure that the dentry's parent still matches it before updating the
lease.

Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Reviewed-by: default avatarYan, Zheng <zyan@redhat.com>
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent 80d025ff

fs/ceph/inode.c

+48 −24
Original line number Diff line number Diff line
@@ -1016,7 +1016,9 @@ out: 
static void update_dentry_lease(struct dentry *dentry,

				struct ceph_mds_reply_lease *lease,

				struct ceph_mds_session *session,

				unsigned long from_time)

				unsigned long from_time,

				struct ceph_vino *tgt_vino,

				struct ceph_vino *dir_vino)

{

	struct ceph_dentry_info *di = ceph_dentry(dentry);

	long unsigned duration = le32_to_cpu(lease->duration_ms);
@@ -1024,13 +1026,27 @@ static void update_dentry_lease(struct dentry *dentry, 
	long unsigned half_ttl = from_time + (duration * HZ / 2) / 1000;

	struct inode *dir;



	/*

	 * Make sure dentry's inode matches tgt_vino. NULL tgt_vino means that

	 * we expect a negative dentry.

	 */

	if (!tgt_vino && d_really_is_positive(dentry))

		return;



	if (tgt_vino && (d_really_is_negative(dentry) ||

			!ceph_ino_compare(d_inode(dentry), tgt_vino)))

		return;



	spin_lock(&dentry->d_lock);

	dout("update_dentry_lease %p duration %lu ms ttl %lu\n",

	     dentry, duration, ttl);



	/* make lease_rdcache_gen match directory */

	dir = d_inode(dentry->d_parent);



	/* make sure parent matches dir_vino */

	if (!ceph_ino_compare(dir, dir_vino))

		goto out_unlock;



	/* only track leases on regular dentries */

	if (ceph_snap(dir) != CEPH_NOSNAP)

		goto out_unlock;
@@ -1113,7 +1129,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req) 
	struct ceph_mds_session *session = req->r_session;

	struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;

	struct inode *in = NULL;

	struct ceph_vino vino;

	struct ceph_vino tvino, dvino;

	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);

	int err = 0;
@@ -1154,8 +1170,8 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req) 
			dname.name = rinfo->dname;

			dname.len = rinfo->dname_len;

			dname.hash = full_name_hash(parent, dname.name, dname.len);

			vino.ino = le64_to_cpu(rinfo->targeti.in->ino);

			vino.snap = le64_to_cpu(rinfo->targeti.in->snapid);

			tvino.ino = le64_to_cpu(rinfo->targeti.in->ino);

			tvino.snap = le64_to_cpu(rinfo->targeti.in->snapid);

retry_lookup:

			dn = d_lookup(parent, &dname);

			dout("d_lookup on parent=%p name=%.*s got %p\n",
@@ -1172,8 +1188,8 @@ retry_lookup: 
				}

				err = 0;

			} else if (d_really_is_positive(dn) &&

				   (ceph_ino(d_inode(dn)) != vino.ino ||

				    ceph_snap(d_inode(dn)) != vino.snap)) {

				   (ceph_ino(d_inode(dn)) != tvino.ino ||

				    ceph_snap(d_inode(dn)) != tvino.snap)) {

				dout(" dn %p points to wrong inode %p\n",

				     dn, d_inode(dn));

				d_delete(dn);
@@ -1187,10 +1203,10 @@ retry_lookup: 
	}



	if (rinfo->head->is_target) {

		vino.ino = le64_to_cpu(rinfo->targeti.in->ino);

		vino.snap = le64_to_cpu(rinfo->targeti.in->snapid);

		tvino.ino = le64_to_cpu(rinfo->targeti.in->ino);

		tvino.snap = le64_to_cpu(rinfo->targeti.in->snapid);



		in = ceph_get_inode(sb, vino);

		in = ceph_get_inode(sb, tvino);

		if (IS_ERR(in)) {

			err = PTR_ERR(in);

			goto done;
@@ -1231,10 +1247,12 @@ retry_lookup: 
		BUG_ON(!dn);

		BUG_ON(!dir);

		BUG_ON(d_inode(dn->d_parent) != dir);

		BUG_ON(ceph_ino(dir) !=

		       le64_to_cpu(rinfo->diri.in->ino));

		BUG_ON(ceph_snap(dir) !=

		       le64_to_cpu(rinfo->diri.in->snapid));



		dvino.ino = le64_to_cpu(rinfo->diri.in->ino);

		dvino.snap = le64_to_cpu(rinfo->diri.in->snapid);



		BUG_ON(ceph_ino(dir) != dvino.ino);

		BUG_ON(ceph_snap(dir) != dvino.snap);



		/* do we have a lease on the whole dir? */

		have_dir_cap =
@@ -1291,7 +1309,8 @@ retry_lookup: 
					d_add(dn, NULL);

				update_dentry_lease(dn, rinfo->dlease,

						    session,

						    req->r_request_started);

						    req->r_request_started,

						    NULL, &dvino);

			}

			goto done;

		}
@@ -1314,9 +1333,13 @@ retry_lookup: 
			have_lease = false;

		}



		if (have_lease)

		if (have_lease) {

			tvino.ino = le64_to_cpu(rinfo->targeti.in->ino);

			tvino.snap = le64_to_cpu(rinfo->targeti.in->snapid);

			update_dentry_lease(dn, rinfo->dlease, session,

					    req->r_request_started);

					    req->r_request_started,

					    &tvino, &dvino);

		}

		dout(" final dn %p\n", dn);

	} else if ((req->r_op == CEPH_MDS_OP_LOOKUPSNAP ||

		    req->r_op == CEPH_MDS_OP_MKSNAP) &&
@@ -1490,14 +1513,14 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req, 
	/* FIXME: release caps/leases if error occurs */

	for (i = 0; i < rinfo->dir_nr; i++) {

		struct ceph_mds_reply_dir_entry *rde = rinfo->dir_entries + i;

		struct ceph_vino vino;

		struct ceph_vino tvino, dvino;



		dname.name = rde->name;

		dname.len = rde->name_len;

		dname.hash = full_name_hash(parent, dname.name, dname.len);



		vino.ino = le64_to_cpu(rde->inode.in->ino);

		vino.snap = le64_to_cpu(rde->inode.in->snapid);

		tvino.ino = le64_to_cpu(rde->inode.in->ino);

		tvino.snap = le64_to_cpu(rde->inode.in->snapid);



		if (rinfo->hash_order) {

			u32 hash = ceph_str_hash(ci->i_dir_layout.dl_dir_hash,
@@ -1526,8 +1549,8 @@ retry_lookup: 
				goto out;

			}

		} else if (d_really_is_positive(dn) &&

			   (ceph_ino(d_inode(dn)) != vino.ino ||

			    ceph_snap(d_inode(dn)) != vino.snap)) {

			   (ceph_ino(d_inode(dn)) != tvino.ino ||

			    ceph_snap(d_inode(dn)) != tvino.snap)) {

			dout(" dn %p points to wrong inode %p\n",

			     dn, d_inode(dn));

			d_delete(dn);
@@ -1539,7 +1562,7 @@ retry_lookup: 
		if (d_really_is_positive(dn)) {

			in = d_inode(dn);

		} else {

			in = ceph_get_inode(parent->d_sb, vino);

			in = ceph_get_inode(parent->d_sb, tvino);

			if (IS_ERR(in)) {

				dout("new_inode badness\n");

				d_drop(dn);
@@ -1584,8 +1607,9 @@ retry_lookup: 


		ceph_dentry(dn)->offset = rde->offset;



		dvino = ceph_vino(d_inode(parent));

		update_dentry_lease(dn, rde->lease, req->r_session,

				    req->r_request_started);

				    req->r_request_started, &tvino, &dvino);



		if (err == 0 && skipped == 0 && cache_ctl.index >= 0) {

			ret = fill_readdir_cache(d_inode(parent), dn,

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