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;
diff --git a/fs/ubifs/scan.c b/fs/ubifs/scan.c
index acf5c5f..0ed8247 100644
--- a/fs/ubifs/scan.c
+++ b/fs/ubifs/scan.c
@@ -87,7 +87,7 @@
dbg_scan("scanning %s", dbg_ntype(ch->node_type));
- if (ubifs_check_node(c, buf, lnum, offs, quiet))
+ if (ubifs_check_node(c, buf, lnum, offs, quiet, 1))
return SCANNED_A_CORRUPT_NODE;
if (ch->node_type == UBIFS_PAD_NODE) {
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;
}
diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index d279012..66dc571 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -470,6 +470,10 @@
if (node_len != len)
return 0;
+ if (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)
@@ -1687,7 +1691,7 @@
goto out_err;
}
- err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0);
+ err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0);
if (err) {
ubifs_err("expected node type %d", UBIFS_DATA_NODE);
goto out;
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 8513239..d6ae3f7 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -894,10 +894,12 @@
* 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 @@
* @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 @@
* @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 @@
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_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_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);