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>

1 files changed, 10 insertions, 1 deletions

diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 8513239ea8a0..d6ae3f7b2b05 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -894,10 +894,12 @@ struct ubifs_orphan {
  * struct ubifs_mount_opts - UBIFS-specific mount options information.
  * @unmount_mode: selected unmount mode (%0 default, %1 normal, %2 fast)
  * @bulk_read: enable bulk-reads
+ * @chk_data_crc: check CRCs when reading data nodes
  */
 struct ubifs_mount_opts {
         unsigned int unmount_mode:2;
         unsigned int bulk_read:2;
+        unsigned int chk_data_crc:2;
 };
 
 /**
@@ -1001,6 +1003,9 @@ struct ubifs_mount_opts {
  * @bulk_read: enable bulk-reads
  * @bulk_read_buf_size: buffer size for bulk-reads
  *
+ * @no_chk_data_crc: do not check CRCs when reading data nodes (except during
+ *                   recovery)
+ *
  * @dirty_pg_cnt: number of dirty pages (not used)
  * @dirty_zn_cnt: number of dirty znodes
  * @clean_zn_cnt: number of clean znodes
@@ -1138,6 +1143,7 @@ struct ubifs_mount_opts {
  * @rcvrd_mst_node: recovered master node to write when mounting ro to rw
  * @size_tree: inode size information for recovery
  * @remounting_rw: set while remounting from ro to rw (sb flags have MS_RDONLY)
+ * @always_chk_crc: always check CRCs (while mounting and remounting rw)
  * @mount_opts: UBIFS-specific mount options
  *
  * @dbg_buf: a buffer of LEB size used for debugging purposes
@@ -1244,6 +1250,8 @@ struct ubifs_info {
         int bulk_read;
         int bulk_read_buf_size;
 
+        int no_chk_data_crc;
+
         atomic_long_t dirty_pg_cnt;
         atomic_long_t dirty_zn_cnt;
         atomic_long_t clean_zn_cnt;
@@ -1374,6 +1382,7 @@ struct ubifs_info {
         struct ubifs_mst_node *rcvrd_mst_node;
         struct rb_root size_tree;
         int remounting_rw;
+        int always_chk_crc;
         struct ubifs_mount_opts mount_opts;
 
 #ifdef CONFIG_UBIFS_FS_DEBUG
@@ -1416,7 +1425,7 @@ int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
 int ubifs_write_node(struct ubifs_info *c, void *node, int len, int lnum,
                      int offs, int dtype);
 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);
 void ubifs_prepare_node(struct ubifs_info *c, void *buf, int len, 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);