Merge branch 'linux-next' of git://git.infradead.org/ubifs-2.6

[linux-2.6-block.git] / fs / ubifs / io.c

diff --git a/fs/ubifs/io.c b/fs/ubifs/io.c
index 3374f91b67091f9516c4909b41889fd9f2a3912e..01682713af69e9e4f20b9648cfc4f74380da2da8 100644 (file)
--- a/fs/ubifs/io.c
+++ b/fs/ubifs/io.c
@@ -53,6 +53,21 @@
 #include <linux/crc32.h>
 #include "ubifs.h"
 
+/**
+ * ubifs_ro_mode - switch UBIFS to read read-only mode.
+ * @c: UBIFS file-system description object
+ * @err: error code which is the reason of switching to R/O mode
+ */
+void ubifs_ro_mode(struct ubifs_info *c, int err)
+{
+       if (!c->ro_media) {
+               c->ro_media = 1;
+               c->no_chk_data_crc = 0;
+               ubifs_warn("switched to read-only mode, error %d", err);
+               dbg_dump_stack();
+       }
+}
+
 /**
  * ubifs_check_node - check node.
  * @c: UBIFS file-system description object
@@ -60,6 +75,7 @@
  * @lnum: logical eraseblock number
  * @offs: offset within the logical eraseblock
  * @quiet: print no messages
+ * @chk_crc: indicates whether to always check the CRC
  *
  * This function checks node magic number and CRC checksum. This function also
  * validates node length to prevent UBIFS from becoming crazy when an attacker
@@ -71,7 +87,7 @@
  * or magic.
  */
 int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
-                    int offs, int quiet)
+                    int offs, int quiet, int chk_crc)
 {
        int err = -EINVAL, type, node_len;
        uint32_t crc, node_crc, magic;
@@ -107,6 +123,10 @@ int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum,
                   node_len > c->ranges[type].max_len)
                goto out_len;
 
+       if (!chk_crc && type == UBIFS_DATA_NODE && !c->always_chk_crc)
+               if (c->no_chk_data_crc)
+                       return 0;
+
        crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
        node_crc = le32_to_cpu(ch->crc);
        if (crc != node_crc) {
@@ -708,7 +728,7 @@ int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
                goto out;
        }
 
-       err = ubifs_check_node(c, buf, lnum, offs, 0);
+       err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
        if (err) {
                ubifs_err("expected node type %d", type);
                return err;
@@ -767,7 +787,7 @@ int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
                goto out;
        }
 
-       err = ubifs_check_node(c, buf, lnum, offs, 0);
+       err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
        if (err) {
                ubifs_err("expected node type %d", type);
                return err;