UBIFS: add no_chk_data_crc mount option
UBIFS read performance can be improved by skipping the CRC
check when data nodes are read. This option can be used if
the underlying media is considered to be highly reliable.
Note that CRCs are always checked for metadata.
Read speed on Arm platform with OneNAND goes from 19 MiB/s
to 27 MiB/s with data CRC checking disabled.
Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
diff --git a/fs/ubifs/io.c b/fs/ubifs/io.c
index 054363f..40e2790 100644
--- a/fs/ubifs/io.c
+++ b/fs/ubifs/io.c
@@ -74,6 +74,7 @@
* @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
@@ -85,7 +86,7 @@
* 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;
@@ -121,6 +122,10 @@
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) {
@@ -722,7 +727,7 @@
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;
@@ -781,7 +786,7 @@
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;