Merge tag 'ceph-for-5.1-rc7' of git://github.com/ceph/ceph-client

Pull ceph fixes from Ilya Dryomov:
 "dentry name handling fixes from Jeff and a memory leak fix from Zheng.

  Both are old issues, marked for stable"

* tag 'ceph-for-5.1-rc7' of git://github.com/ceph/ceph-client:
  ceph: fix ci->i_head_snapc leak
  ceph: handle the case where a dentry has been renamed on outstanding req
  ceph: ensure d_name stability in ceph_dentry_hash()
  ceph: only use d_name directly when parent is locked

fs/ceph/dir.c

@@ -1766,6 +1766,7 @@ static ssize_t ceph_read_dir(struct file *file, char __user *buf, size_t size,
 unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn)
 {
 	struct ceph_inode_info *dci = ceph_inode(dir);
+	unsigned hash;
 
 	switch (dci->i_dir_layout.dl_dir_hash) {
 	case 0:	/* for backward compat */
@@ -1773,8 +1774,11 @@ unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn)
 		return dn->d_name.hash;
 
 	default:
-		return ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
+		spin_lock(&dn->d_lock);
+		hash = ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
 				     dn->d_name.name, dn->d_name.len);
+		spin_unlock(&dn->d_lock);
+		return hash;
 	}
 }
 

fs/ceph/inode.c

@@ -1163,6 +1163,19 @@ static int splice_dentry(struct dentry **pdn, struct inode *in)
 	return 0;
 }
 
+static int d_name_cmp(struct dentry *dentry, const char *name, size_t len)
+{
+	int ret;
+
+	/* take d_lock to ensure dentry->d_name stability */
+	spin_lock(&dentry->d_lock);
+	ret = dentry->d_name.len - len;
+	if (!ret)
+		ret = memcmp(dentry->d_name.name, name, len);
+	spin_unlock(&dentry->d_lock);
+	return ret;
+}
+
 /*
  * Incorporate results into the local cache.  This is either just
  * one inode, or a directory, dentry, and possibly linked-to inode (e.g.,
@@ -1412,7 +1425,8 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req)
 		err = splice_dentry(&req->r_dentry, in);
 		if (err < 0)
 			goto done;
-	} else if (rinfo->head->is_dentry) {
+	} else if (rinfo->head->is_dentry &&
+		   !d_name_cmp(req->r_dentry, rinfo->dname, rinfo->dname_len)) {
 		struct ceph_vino *ptvino = NULL;
 
 		if ((le32_to_cpu(rinfo->diri.in->cap.caps) & CEPH_CAP_FILE_SHARED) ||

fs/ceph/mds_client.c

@@ -1414,6 +1414,15 @@ static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
 			list_add(&ci->i_prealloc_cap_flush->i_list, &to_remove);
 			ci->i_prealloc_cap_flush = NULL;
 		}
+
+               if (drop &&
+                  ci->i_wrbuffer_ref_head == 0 &&
+                  ci->i_wr_ref == 0 &&
+                  ci->i_dirty_caps == 0 &&
+                  ci->i_flushing_caps == 0) {
+                      ceph_put_snap_context(ci->i_head_snapc);
+                      ci->i_head_snapc = NULL;
+               }
 	}
 	spin_unlock(&ci->i_ceph_lock);
 	while (!list_empty(&to_remove)) {
@@ -2161,10 +2170,39 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,
 	return path;
 }
 
+/* Duplicate the dentry->d_name.name safely */
+static int clone_dentry_name(struct dentry *dentry, const char **ppath,
+			     int *ppathlen)
+{
+	u32 len;
+	char *name;
+
+retry:
+	len = READ_ONCE(dentry->d_name.len);
+	name = kmalloc(len + 1, GFP_NOFS);
+	if (!name)
+		return -ENOMEM;
+
+	spin_lock(&dentry->d_lock);
+	if (dentry->d_name.len != len) {
+		spin_unlock(&dentry->d_lock);
+		kfree(name);
+		goto retry;
+	}
+	memcpy(name, dentry->d_name.name, len);
+	spin_unlock(&dentry->d_lock);
+
+	name[len] = '\0';
+	*ppath = name;
+	*ppathlen = len;
+	return 0;
+}
+
 static int build_dentry_path(struct dentry *dentry, struct inode *dir,
 			     const char **ppath, int *ppathlen, u64 *pino,
-			     int *pfreepath)
+			     bool *pfreepath, bool parent_locked)
 {
+	int ret;
 	char *path;
 
 	rcu_read_lock();
@@ -2173,8 +2211,15 @@ static int build_dentry_path(struct dentry *dentry, struct inode *dir,
 	if (dir && ceph_snap(dir) == CEPH_NOSNAP) {
 		*pino = ceph_ino(dir);
 		rcu_read_unlock();
-		*ppath = dentry->d_name.name;
-		*ppathlen = dentry->d_name.len;
+		if (parent_locked) {
+			*ppath = dentry->d_name.name;
+			*ppathlen = dentry->d_name.len;
+		} else {
+			ret = clone_dentry_name(dentry, ppath, ppathlen);
+			if (ret)
+				return ret;
+			*pfreepath = true;
+		}
 		return 0;
 	}
 	rcu_read_unlock();
@@ -2182,13 +2227,13 @@ static int build_dentry_path(struct dentry *dentry, struct inode *dir,
 	if (IS_ERR(path))
 		return PTR_ERR(path);
 	*ppath = path;
-	*pfreepath = 1;
+	*pfreepath = true;
 	return 0;
 }
 
 static int build_inode_path(struct inode *inode,
 			    const char **ppath, int *ppathlen, u64 *pino,
-			    int *pfreepath)
+			    bool *pfreepath)
 {
 	struct dentry *dentry;
 	char *path;
@@ -2204,7 +2249,7 @@ static int build_inode_path(struct inode *inode,
 	if (IS_ERR(path))
 		return PTR_ERR(path);
 	*ppath = path;
-	*pfreepath = 1;
+	*pfreepath = true;
 	return 0;
 }
 
@@ -2215,7 +2260,7 @@ static int build_inode_path(struct inode *inode,
 static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
 				  struct inode *rdiri, const char *rpath,
 				  u64 rino, const char **ppath, int *pathlen,
-				  u64 *ino, int *freepath)
+				  u64 *ino, bool *freepath, bool parent_locked)
 {
 	int r = 0;
 
@@ -2225,7 +2270,7 @@ static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
 		     ceph_snap(rinode));
 	} else if (rdentry) {
 		r = build_dentry_path(rdentry, rdiri, ppath, pathlen, ino,
-					freepath);
+					freepath, parent_locked);
 		dout(" dentry %p %llx/%.*s\n", rdentry, *ino, *pathlen,
 		     *ppath);
 	} else if (rpath || rino) {
@@ -2251,7 +2296,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
 	const char *path2 = NULL;
 	u64 ino1 = 0, ino2 = 0;
 	int pathlen1 = 0, pathlen2 = 0;
-	int freepath1 = 0, freepath2 = 0;
+	bool freepath1 = false, freepath2 = false;
 	int len;
 	u16 releases;
 	void *p, *end;
@@ -2259,16 +2304,19 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
 
 	ret = set_request_path_attr(req->r_inode, req->r_dentry,
 			      req->r_parent, req->r_path1, req->r_ino1.ino,
-			      &path1, &pathlen1, &ino1, &freepath1);
+			      &path1, &pathlen1, &ino1, &freepath1,
+			      test_bit(CEPH_MDS_R_PARENT_LOCKED,
+					&req->r_req_flags));
 	if (ret < 0) {
 		msg = ERR_PTR(ret);
 		goto out;
 	}
 
+	/* If r_old_dentry is set, then assume that its parent is locked */
 	ret = set_request_path_attr(NULL, req->r_old_dentry,
 			      req->r_old_dentry_dir,
 			      req->r_path2, req->r_ino2.ino,
-			      &path2, &pathlen2, &ino2, &freepath2);
+			      &path2, &pathlen2, &ino2, &freepath2, true);
 	if (ret < 0) {
 		msg = ERR_PTR(ret);
 		goto out_free1;

fs/ceph/snap.c

@@ -572,7 +572,12 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci)
 	old_snapc = NULL;
 
 update_snapc:
-	if (ci->i_head_snapc) {
+       if (ci->i_wrbuffer_ref_head == 0 &&
+           ci->i_wr_ref == 0 &&
+           ci->i_dirty_caps == 0 &&
+           ci->i_flushing_caps == 0) {
+               ci->i_head_snapc = NULL;
+       } else {
 		ci->i_head_snapc = ceph_get_snap_context(new_snapc);
 		dout(" new snapc is %p\n", new_snapc);
 	}