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/super.c b/fs/ubifs/super.c
index b1c57e8..cf078b5 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -406,6 +406,11 @@
else if (c->mount_opts.bulk_read == 1)
seq_printf(s, ",no_bulk_read");
+ if (c->mount_opts.chk_data_crc == 2)
+ seq_printf(s, ",chk_data_crc");
+ else if (c->mount_opts.chk_data_crc == 1)
+ seq_printf(s, ",no_chk_data_crc");
+
return 0;
}
@@ -859,6 +864,8 @@
* Opt_norm_unmount: run a journal commit before un-mounting
* Opt_bulk_read: enable bulk-reads
* Opt_no_bulk_read: disable bulk-reads
+ * Opt_chk_data_crc: check CRCs when reading data nodes
+ * Opt_no_chk_data_crc: do not check CRCs when reading data nodes
* Opt_err: just end of array marker
*/
enum {
@@ -866,6 +873,8 @@
Opt_norm_unmount,
Opt_bulk_read,
Opt_no_bulk_read,
+ Opt_chk_data_crc,
+ Opt_no_chk_data_crc,
Opt_err,
};
@@ -874,6 +883,8 @@
{Opt_norm_unmount, "norm_unmount"},
{Opt_bulk_read, "bulk_read"},
{Opt_no_bulk_read, "no_bulk_read"},
+ {Opt_chk_data_crc, "chk_data_crc"},
+ {Opt_no_chk_data_crc, "no_chk_data_crc"},
{Opt_err, NULL},
};
@@ -919,6 +930,14 @@
c->mount_opts.bulk_read = 1;
c->bulk_read = 0;
break;
+ case Opt_chk_data_crc:
+ c->mount_opts.chk_data_crc = 2;
+ c->no_chk_data_crc = 0;
+ break;
+ case Opt_no_chk_data_crc:
+ c->mount_opts.chk_data_crc = 1;
+ c->no_chk_data_crc = 1;
+ break;
default:
ubifs_err("unrecognized mount option \"%s\" "
"or missing value", p);
@@ -1027,6 +1046,8 @@
goto out_free;
}
+ c->always_chk_crc = 1;
+
err = ubifs_read_superblock(c);
if (err)
goto out_free;
@@ -1168,6 +1189,8 @@
if (err)
goto out_infos;
+ c->always_chk_crc = 0;
+
ubifs_msg("mounted UBI device %d, volume %d, name \"%s\"",
c->vi.ubi_num, c->vi.vol_id, c->vi.name);
if (mounted_read_only)
@@ -1313,6 +1336,7 @@
mutex_lock(&c->umount_mutex);
c->remounting_rw = 1;
+ c->always_chk_crc = 1;
/* Check for enough free space */
if (ubifs_calc_available(c, c->min_idx_lebs) <= 0) {
@@ -1381,13 +1405,15 @@
c->bgt = NULL;
ubifs_err("cannot spawn \"%s\", error %d",
c->bgt_name, err);
- return err;
+ goto out;
}
wake_up_process(c->bgt);
c->orph_buf = vmalloc(c->leb_size);
- if (!c->orph_buf)
- return -ENOMEM;
+ if (!c->orph_buf) {
+ err = -ENOMEM;
+ goto out;
+ }
/* Check for enough log space */
lnum = c->lhead_lnum + 1;
@@ -1414,6 +1440,7 @@
dbg_gen("re-mounted read-write");
c->vfs_sb->s_flags &= ~MS_RDONLY;
c->remounting_rw = 0;
+ c->always_chk_crc = 0;
mutex_unlock(&c->umount_mutex);
return 0;
@@ -1429,6 +1456,7 @@
c->ileb_buf = NULL;
ubifs_lpt_free(c, 1);
c->remounting_rw = 0;
+ c->always_chk_crc = 0;
mutex_unlock(&c->umount_mutex);
return err;
}