UBIFS: fix dbg_chk_lpt_sz()

The debugging function dbg_chk_lpt_sz() was not working
correctly for small min_io_unit size e.g. NOR flash.

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

fs/ubifs/lpt_commit.c

@@ -229,7 +229,7 @@ static int layout_cnodes(struct ubifs_info *c)
 		while (offs + len > c->leb_size) {
 			alen = ALIGN(offs, c->min_io_size);
 			upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
-			dbg_chk_lpt_sz(c, 2, alen - offs);
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
 			err = alloc_lpt_leb(c, &lnum);
 			if (err)
 				goto no_space;
@@ -272,7 +272,7 @@ static int layout_cnodes(struct ubifs_info *c)
 		if (offs + c->lsave_sz > c->leb_size) {
 			alen = ALIGN(offs, c->min_io_size);
 			upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
-			dbg_chk_lpt_sz(c, 2, alen - offs);
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
 			err = alloc_lpt_leb(c, &lnum);
 			if (err)
 				goto no_space;
@@ -292,7 +292,7 @@ static int layout_cnodes(struct ubifs_info *c)
 		if (offs + c->ltab_sz > c->leb_size) {
 			alen = ALIGN(offs, c->min_io_size);
 			upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
-			dbg_chk_lpt_sz(c, 2, alen - offs);
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
 			err = alloc_lpt_leb(c, &lnum);
 			if (err)
 				goto no_space;
@@ -416,9 +416,8 @@ static int write_cnodes(struct ubifs_info *c)
 						       alen, UBI_SHORTTERM);
 				if (err)
 					return err;
-				dbg_chk_lpt_sz(c, 4, alen - wlen);
 			}
-			dbg_chk_lpt_sz(c, 2, 0);
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
 			err = realloc_lpt_leb(c, &lnum);
 			if (err)
 				goto no_space;
@@ -477,7 +476,7 @@ static int write_cnodes(struct ubifs_info *c)
 					      UBI_SHORTTERM);
 			if (err)
 				return err;
-			dbg_chk_lpt_sz(c, 2, alen - wlen);
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
 			err = realloc_lpt_leb(c, &lnum);
 			if (err)
 				goto no_space;
@@ -504,7 +503,7 @@ static int write_cnodes(struct ubifs_info *c)
 					      UBI_SHORTTERM);
 			if (err)
 				return err;
-			dbg_chk_lpt_sz(c, 2, alen - wlen);
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
 			err = realloc_lpt_leb(c, &lnum);
 			if (err)
 				goto no_space;
@@ -1756,10 +1755,16 @@ int dbg_chk_lpt_free_spc(struct ubifs_info *c)
 /**
  * dbg_chk_lpt_sz - check LPT does not write more than LPT size.
  * @c: the UBIFS file-system description object
- * @action: action
+ * @action: what to do
  * @len: length written
  *
  * This function returns %0 on success and a negative error code on failure.
+ * The @action argument may be one of:
+ *   o %0 - LPT debugging checking starts, initialize debugging variables;
+ *   o %1 - wrote an LPT node, increase LPT size by @len bytes;
+ *   o %2 - switched to a different LEB and wasted @len bytes;
+ *   o %3 - check that we've written the right number of bytes.
+ *   o %4 - wasted @len bytes;
  */
 int dbg_chk_lpt_sz(struct ubifs_info *c, int action, int len)
 {