UBIFS: fix LEB list freeing

When freeing the c->idx_lebs list, we have to release the LEBs as well,
because we might be called from mount to read-only mode code. Otherwise
the LEBs stay taken forever, which may cause problems when we re-mount
back ro RW mode.

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

4 files changed, 48 insertions, 20 deletions

diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c
index b2e5f1133377..9760154d874b 100644
--- a/fs/ubifs/gc.c
+++ b/fs/ubifs/gc.c
@@ -830,21 +830,29 @@ out:
  * ubifs_destroy_idx_gc - destroy idx_gc list.
  * @c: UBIFS file-system description object
  *
- * This function destroys the idx_gc list. It is called when unmounting or
- * remounting read-only so locks are not needed.
+ * This function destroys the @c->idx_gc list. It is called when unmounting or
+ * remounting read-only so locks are not needed. Returns zero in case of
+ * success and a negative error code in case of failure.
  */
-void ubifs_destroy_idx_gc(struct ubifs_info *c)
+int ubifs_destroy_idx_gc(struct ubifs_info *c)
 {
+        int ret = 0;
+
         while (!list_empty(&c->idx_gc)) {
+                int err;
                 struct ubifs_gced_idx_leb *idx_gc;
 
                 idx_gc = list_entry(c->idx_gc.next, struct ubifs_gced_idx_leb,
                                     list);
-                c->idx_gc_cnt -= 1;
+                err = ubifs_change_one_lp(c, idx_gc->lnum, LPROPS_NC,
+                                          LPROPS_NC, 0, LPROPS_TAKEN, -1);
+                if (err && !ret)
+                        ret = err;
                 list_del(&idx_gc->list);
                 kfree(idx_gc);
         }
 
+        return ret;
 }
 
 /**
diff --git a/fs/ubifs/lprops.c b/fs/ubifs/lprops.c
index dfd2bcece27a..68328c59762b 100644
--- a/fs/ubifs/lprops.c
+++ b/fs/ubifs/lprops.c
@@ -678,6 +678,9 @@ int ubifs_change_one_lp(struct ubifs_info *c, int lnum, int free, int dirty,
 
 out:
         ubifs_release_lprops(c);
+        if (err)
+                ubifs_err("cannot change properties of LEB %d, error %d",
+                          lnum, err);
         return err;
 }
 
@@ -714,6 +717,9 @@ int ubifs_update_one_lp(struct ubifs_info *c, int lnum, int free, int dirty,
 
 out:
         ubifs_release_lprops(c);
+        if (err)
+                ubifs_err("cannot update properties of LEB %d, error %d",
+                          lnum, err);
         return err;
 }
 
@@ -737,6 +743,8 @@ int ubifs_read_one_lp(struct ubifs_info *c, int lnum, struct ubifs_lprops *lp)
         lpp = ubifs_lpt_lookup(c, lnum);
         if (IS_ERR(lpp)) {
                 err = PTR_ERR(lpp);
+                ubifs_err("cannot read properties of LEB %d, error %d",
+                          lnum, err);
                 goto out;
         }
 
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index da99da098efd..807bbd3c8b4b 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1469,9 +1469,6 @@ static int ubifs_remount_rw(struct ubifs_info *c)
 {
         int err, lnum;
 
-        if (c->ro_media)
-                return -EINVAL;
-
         mutex_lock(&c->umount_mutex);
         c->remounting_rw = 1;
         c->always_chk_crc = 1;
@@ -1605,9 +1602,13 @@ out:
  */
 static void commit_on_unmount(struct ubifs_info *c)
 {
-        struct super_block *sb = c->vfs_sb;
         long long bud_bytes;
 
+        if (!c->fast_unmount) {
+                dbg_gen("skip committing - fast unmount enabled");
+                return;
+        }
+
         /*
          * This function is called before the background thread is stopped, so
          * we may race with ongoing commit, which means we have to take
@@ -1617,8 +1618,11 @@ static void commit_on_unmount(struct ubifs_info *c)
         bud_bytes = c->bud_bytes;
         spin_unlock(&c->buds_lock);
 
-        if (!c->fast_unmount && !(sb->s_flags & MS_RDONLY) && bud_bytes)
+        if (bud_bytes) {
+                dbg_gen("run commit");
                 ubifs_run_commit(c);
+        } else
+                dbg_gen("journal is empty, do not run commit");
 }
 
 /**
@@ -1633,6 +1637,8 @@ static void ubifs_remount_ro(struct ubifs_info *c)
         int i, err;
 
         ubifs_assert(!c->need_recovery);
+        ubifs_assert(!c->ro_media);
+
         commit_on_unmount(c);
 
         mutex_lock(&c->umount_mutex);
@@ -1646,16 +1652,17 @@ static void ubifs_remount_ro(struct ubifs_info *c)
                 del_timer_sync(&c->jheads[i].wbuf.timer);
         }
 
-        if (!c->ro_media) {
-                c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
-                c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
-                c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
-                err = ubifs_write_master(c);
-                if (err)
-                        ubifs_ro_mode(c, err);
-        }
+        c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
+        c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
+        c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
+        err = ubifs_write_master(c);
+        if (err)
+                ubifs_ro_mode(c, err);
+
+        err = ubifs_destroy_idx_gc(c);
+        if (err)
+                ubifs_ro_mode(c, err);
 
-        ubifs_destroy_idx_gc(c);
         free_wbufs(c);
         vfree(c->orph_buf);
         c->orph_buf = NULL;
@@ -1754,6 +1761,11 @@ static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
         }
 
         if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {
+                if (c->ro_media) {
+                        ubifs_msg("cannot re-mount R/W, UBIFS is working in "
+                                  "R/O mode");
+                        return -EINVAL;
+                }
                 err = ubifs_remount_rw(c);
                 if (err)
                         return err;
@@ -2044,7 +2056,7 @@ static void ubifs_kill_sb(struct super_block *sb)
          * We do 'commit_on_unmount()' here instead of 'ubifs_put_super()'
          * in order to be outside BKL.
          */
-        if (sb->s_root)
+        if (sb->s_root && !(sb->s_flags & MS_RDONLY))
                 commit_on_unmount(c);
         /* The un-mount routine is actually done in put_super() */
         generic_shutdown_super(sb);
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 2e78d6ac007e..ee9517a7b024 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -1593,7 +1593,7 @@ int ubifs_replay_journal(struct ubifs_info *c);
 int ubifs_garbage_collect(struct ubifs_info *c, int anyway);
 int ubifs_gc_start_commit(struct ubifs_info *c);
 int ubifs_gc_end_commit(struct ubifs_info *c);
-void ubifs_destroy_idx_gc(struct ubifs_info *c);
+int ubifs_destroy_idx_gc(struct ubifs_info *c);
 int ubifs_get_idx_gc_leb(struct ubifs_info *c);
 int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp);