2 files changed, 70 insertions, 6 deletions

diff --git a/fs/ubifs/io.c b/fs/ubifs/io.c
index 4bd61fe146e0..d124117efd42 100644
--- a/fs/ubifs/io.c
+++ b/fs/ubifs/io.c
@@ -395,6 +395,39 @@ void ubifs_crc_node(struct ubifs_info *c, void *node, int len)
 }
 
 /**
+ * ubifs_prepare_node_hmac - prepare node to be written to flash.
+ * @c: UBIFS file-system description object
+ * @node: the node to pad
+ * @len: node length
+ * @hmac_offs: offset of the HMAC in the node
+ * @pad: if the buffer has to be padded
+ *
+ * This function prepares node at @node to be written to the media - it
+ * calculates node CRC, fills the common header, and adds proper padding up to
+ * the next minimum I/O unit if @pad is not zero. if @hmac_offs is positive then
+ * a HMAC is inserted into the node at the given offset.
+ *
+ * This function returns 0 for success or a negative error code otherwise.
+ */
+int ubifs_prepare_node_hmac(struct ubifs_info *c, void *node, int len,
+                            int hmac_offs, int pad)
+{
+        int err;
+
+        ubifs_init_node(c, node, len, pad);
+
+        if (hmac_offs > 0) {
+                err = ubifs_node_insert_hmac(c, node, len, hmac_offs);
+                if (err)
+                        return err;
+        }
+
+        ubifs_crc_node(c, node, len);
+
+        return 0;
+}
+
+/**
  * ubifs_prepare_node - prepare node to be written to flash.
  * @c: UBIFS file-system description object
  * @node: the node to pad
@@ -407,8 +440,11 @@ void ubifs_crc_node(struct ubifs_info *c, void *node, int len)
  */
 void ubifs_prepare_node(struct ubifs_info *c, void *node, int len, int pad)
 {
-        ubifs_init_node(c, node, len, pad);
-        ubifs_crc_node(c, node, len);
+        /*
+         * Deliberately ignore return value since this function can only fail
+         * when a hmac offset is given.
+         */
+        ubifs_prepare_node_hmac(c, node, len, 0, pad);
 }
 
 /**
@@ -861,12 +897,13 @@ out:
 }
 
 /**
- * ubifs_write_node - write node to the media.
+ * ubifs_write_node_hmac - write node to the media.
  * @c: UBIFS file-system description object
  * @buf: the node to write
  * @len: node length
  * @lnum: logical eraseblock number
  * @offs: offset within the logical eraseblock
+ * @hmac_offs: offset of the HMAC within the node
  *
  * This function automatically fills node magic number, assigns sequence
  * number, and calculates node CRC checksum. The length of the @buf buffer has
@@ -874,8 +911,8 @@ out:
  * appends padding node and padding bytes if needed. Returns zero in case of
  * success and a negative error code in case of failure.
  */
-int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
-                     int offs)
+int ubifs_write_node_hmac(struct ubifs_info *c, void *buf, int len, int lnum,
+                          int offs, int hmac_offs)
 {
         int err, buf_len = ALIGN(len, c->min_io_size);
 
@@ -890,7 +927,10 @@ int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
         if (c->ro_error)
                 return -EROFS;
 
-        ubifs_prepare_node(c, buf, len, 1);
+        err = ubifs_prepare_node_hmac(c, buf, len, hmac_offs, 1);
+        if (err)
+                return err;
+
         err = ubifs_leb_write(c, lnum, buf, offs, buf_len);
         if (err)
                 ubifs_dump_node(c, buf);
@@ -899,6 +939,26 @@ int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
 }
 
 /**
+ * ubifs_write_node - write node to the media.
+ * @c: UBIFS file-system description object
+ * @buf: the node to write
+ * @len: node length
+ * @lnum: logical eraseblock number
+ * @offs: offset within the logical eraseblock
+ *
+ * This function automatically fills node magic number, assigns sequence
+ * number, and calculates node CRC checksum. The length of the @buf buffer has
+ * to be aligned to the minimal I/O unit size. This function automatically
+ * appends padding node and padding bytes if needed. Returns zero in case of
+ * success and a negative error code in case of failure.
+ */
+int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
+                     int offs)
+{
+        return ubifs_write_node_hmac(c, buf, len, lnum, offs, -1);
+}
+
+/**
  * ubifs_read_node_wbuf - read node from the media or write-buffer.
  * @wbuf: wbuf to check for un-written data
  * @buf: buffer to read to
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 3300f68c4097..42e904b060f9 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -1710,11 +1710,15 @@ int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
                          int lnum, int offs);
 int ubifs_write_node(struct ubifs_info *c, void *node, int len, int lnum,
                      int offs);
+int ubifs_write_node_hmac(struct ubifs_info *c, void *buf, int len, int lnum,
+                          int offs, int hmac_offs);
 int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
                      int offs, int quiet, int must_chk_crc);
 void ubifs_init_node(struct ubifs_info *c, void *buf, int len, int pad);
 void ubifs_crc_node(struct ubifs_info *c, void *buf, int len);
 void ubifs_prepare_node(struct ubifs_info *c, void *buf, int len, int pad);
+int ubifs_prepare_node_hmac(struct ubifs_info *c, void *node, int len,
+                            int hmac_offs, int pad);
 void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last);
 int ubifs_io_init(struct ubifs_info *c);
 void ubifs_pad(const struct ubifs_info *c, void *buf, int pad);