UBIFS: introduce mounting flag

This is a preparational patch which removes the 'c->always_chk_crc' which was
set during mounting and remounting to R/W mode and introduces 'c->mounting'
flag which is set when mounting. Now the 'c->always_chk_crc' flag is the
same as 'c->remounting_rw && c->mounting'.

This patch is a preparation for the next one which will need to know when we
are mounting and remounting to R/W mode, which is exactly what
'c->always_chk_crc' effectively is, but its name does not suite the
next patch. The other possibility would be to just re-name it, but then
we'd end up with less logical flags coverage.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index ad9cf0133622..de485979ca39 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -447,8 +447,11 @@ static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr,
  *
  * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc
  * is true (it is controlled by corresponding mount option). However, if
- * @c->always_chk_crc is true, @c->no_chk_data_crc is ignored and CRC is always
- * checked.
+ * @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to
+ * R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is
+ * because during mounting or re-mounting from R/O mode to R/W mode we may read
+ * journal nodes (when replying the journal or doing the recovery) and the
+ * journal nodes may potentially be corrupted, so checking is required.
  */
 static int try_read_node(const struct ubifs_info *c, void *buf, int type,
 			 int len, int lnum, int offs)
@@ -476,7 +479,8 @@ static int try_read_node(const struct ubifs_info *c, void *buf, int type,
 	if (node_len != len)
 		return 0;
 
-	if (type == UBIFS_DATA_NODE && !c->always_chk_crc && c->no_chk_data_crc)
+	if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting &&
+	    !c->remounting_rw)
 		return 1;
 
 	crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);