[PATCH v2 6/7] ceph: use the parent inode of '.snap' to encrypt name to build path

[xiubli@xxxxxxxxxx]

From: Xiubo Li <xiubli@xxxxxxxxxx>

The inode for '.snap' directory will always with no key setup, so
we can use the parent inode to do this.

Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
---
 fs/ceph/mds_client.c | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 3dea96df4769..5433e6050563 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2465,8 +2465,8 @@ static u8 *get_fscrypt_altname(const struct ceph_mds_request *req, u32 *plen)
  */
 char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, int for_wire)
 {
-	struct dentry *cur;
-	struct inode *inode;
+	struct dentry *cur, *parent;
+	struct inode *inode, *pinode;
 	char *path;
 	int pos;
 	unsigned seq;
@@ -2479,13 +2479,16 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, int for
 	if (!path)
 		return ERR_PTR(-ENOMEM);
 retry:
+	pinode = NULL;
+	parent = NULL;
 	pos = PATH_MAX - 1;
 	path[pos] = '\0';
 
 	seq = read_seqbegin(&rename_lock);
 	cur = dget(dentry);
 	for (;;) {
-		struct dentry *parent;
+		parent = dget_parent(cur);
+		pinode = ceph_get_snap_parent_inode(d_inode(parent));
 
 		spin_lock(&cur->d_lock);
 		inode = d_inode(cur);
@@ -2493,12 +2496,11 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, int for
 			dout("build_path path+%d: %p SNAPDIR\n",
 			     pos, cur);
 			spin_unlock(&cur->d_lock);
-			parent = dget_parent(cur);
 		} else if (for_wire && inode && dentry != cur && ceph_snap(inode) == CEPH_NOSNAP) {
 			spin_unlock(&cur->d_lock);
 			pos++; /* get rid of any prepended '/' */
 			break;
-		} else if (!for_wire || !IS_ENCRYPTED(d_inode(cur->d_parent))) {
+		} else if (!for_wire || !IS_ENCRYPTED(pinode)) {
 			pos -= cur->d_name.len;
 			if (pos < 0) {
 				spin_unlock(&cur->d_lock);
@@ -2506,7 +2508,6 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, int for
 			}
 			memcpy(path + pos, cur->d_name.name, cur->d_name.len);
 			spin_unlock(&cur->d_lock);
-			parent = dget_parent(cur);
 		} else {
 			int len, ret;
 			char buf[FSCRYPT_BASE64URL_CHARS(NAME_MAX)];
@@ -2518,32 +2519,32 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, int for
 			memcpy(buf, cur->d_name.name, cur->d_name.len);
 			len = cur->d_name.len;
 			spin_unlock(&cur->d_lock);
-			parent = dget_parent(cur);
 
-			ret = __fscrypt_prepare_readdir(d_inode(parent));
+			ret = __fscrypt_prepare_readdir(pinode);
 			if (ret < 0) {
 				dput(parent);
 				dput(cur);
+				iput(pinode);
 				return ERR_PTR(ret);
 			}
 
-			if (fscrypt_has_encryption_key(d_inode(parent))) {
-				len = ceph_encode_encrypted_fname(d_inode(parent), cur, buf);
+			if (fscrypt_has_encryption_key(pinode)) {
+				len = ceph_encode_encrypted_fname(pinode, cur, buf);
 				if (len < 0) {
 					dput(parent);
 					dput(cur);
+					iput(pinode);
 					return ERR_PTR(len);
 				}
 			}
 			pos -= len;
-			if (pos < 0) {
-				dput(parent);
+			if (pos < 0)
 				break;
-			}
 			memcpy(path + pos, buf, len);
 		}
 		dput(cur);
 		cur = parent;
+		parent = NULL;
 
 		/* Are we at the root? */
 		if (IS_ROOT(cur))
@@ -2554,7 +2555,13 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, int for
 			break;
 
 		path[pos] = '/';
+		iput(pinode);
+		pinode = NULL;
 	}
+	if (pinode)
+		iput(pinode);
+	if (parent)
+		dput(parent);
 	inode = d_inode(cur);
 	base = inode ? ceph_ino(inode) : 0;
 	dput(cur);
-- 
2.27.0