UBIFS: add re-mount debugging checks

We observe space corrupted accounting when re-mounting. So add some
debbugging checks to catch problems like this.

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

1 files changed, 25 insertions, 10 deletions

diff --git a/fs/ubifs/budget.c b/fs/ubifs/budget.c
index 175f9c590b77..f393620890ee 100644
--- a/fs/ubifs/budget.c
+++ b/fs/ubifs/budget.c
@@ -689,7 +689,7 @@ long long ubifs_reported_space(const struct ubifs_info *c, long long free)
 }
 
 /**
- * ubifs_get_free_space - return amount of free space.
+ * ubifs_get_free_space_nolock - return amount of free space.
  * @c: UBIFS file-system description object
  *
  * This function calculates amount of free space to report to user-space.
@@ -704,16 +704,14 @@ long long ubifs_reported_space(const struct ubifs_info *c, long long free)
  * traditional file-systems, because they have way less overhead than UBIFS.
  * So, to keep users happy, UBIFS tries to take the overhead into account.
  */
-long long ubifs_get_free_space(struct ubifs_info *c)
+long long ubifs_get_free_space_nolock(struct ubifs_info *c)
 {
-        int min_idx_lebs, rsvd_idx_lebs, lebs;
+        int rsvd_idx_lebs, lebs;
         long long available, outstanding, free;
 
-        spin_lock(&c->space_lock);
-        min_idx_lebs = c->min_idx_lebs;
-        ubifs_assert(min_idx_lebs == ubifs_calc_min_idx_lebs(c));
+        ubifs_assert(c->min_idx_lebs == ubifs_calc_min_idx_lebs(c));
         outstanding = c->budg_data_growth + c->budg_dd_growth;
-        available = ubifs_calc_available(c, min_idx_lebs);
+        available = ubifs_calc_available(c, c->min_idx_lebs);
 
         /*
          * When reporting free space to user-space, UBIFS guarantees that it is
@@ -726,15 +724,14 @@ long long ubifs_get_free_space(struct ubifs_info *c)
          * Note, the calculations below are similar to what we have in
          * 'do_budget_space()', so refer there for comments.
          */
-        if (min_idx_lebs > c->lst.idx_lebs)
-                rsvd_idx_lebs = min_idx_lebs - c->lst.idx_lebs;
+        if (c->min_idx_lebs > c->lst.idx_lebs)
+                rsvd_idx_lebs = c->min_idx_lebs - c->lst.idx_lebs;
         else
                 rsvd_idx_lebs = 0;
         lebs = c->lst.empty_lebs + c->freeable_cnt + c->idx_gc_cnt -
                c->lst.taken_empty_lebs;
         lebs -= rsvd_idx_lebs;
         available += lebs * (c->dark_wm - c->leb_overhead);
-        spin_unlock(&c->space_lock);
 
         if (available > outstanding)
                 free = ubifs_reported_space(c, available - outstanding);
@@ -742,3 +739,21 @@ long long ubifs_get_free_space(struct ubifs_info *c)
                 free = 0;
         return free;
 }
+
+/**
+ * ubifs_get_free_space - return amount of free space.
+ * @c: UBIFS file-system description object
+ *
+ * This function calculates and retuns amount of free space to report to
+ * user-space.
+ */
+long long ubifs_get_free_space(struct ubifs_info *c)
+{
+        long long free;
+
+        spin_lock(&c->space_lock);
+        free = ubifs_get_free_space_nolock(c);
+        spin_unlock(&c->space_lock);
+
+        return free;
+}