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, 87 insertions, 33 deletions

diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c
index 792c5a16c182..9a41f6f245b7 100644
--- a/fs/ubifs/debug.c
+++ b/fs/ubifs/debug.c
@@ -620,9 +620,11 @@ void dbg_dump_budg(struct ubifs_info *c)
                c->dark_wm, c->dead_wm, c->max_idx_node_sz);
         printk(KERN_DEBUG "\tgc_lnum %d, ihead_lnum %d\n",
                c->gc_lnum, c->ihead_lnum);
-        for (i = 0; i < c->jhead_cnt; i++)
-                printk(KERN_DEBUG "\tjhead %d\t LEB %d\n",
-                       c->jheads[i].wbuf.jhead, c->jheads[i].wbuf.lnum);
+        /* If we are in R/O mode, journal heads do not exist */
+        if (c->jheads)
+                for (i = 0; i < c->jhead_cnt; i++)
+                        printk(KERN_DEBUG "\tjhead %d\t LEB %d\n",
+                               c->jheads[i].wbuf.jhead, c->jheads[i].wbuf.lnum);
         for (rb = rb_first(&c->buds); rb; rb = rb_next(rb)) {
                 bud = rb_entry(rb, struct ubifs_bud, rb);
                 printk(KERN_DEBUG "\tbud LEB %d\n", bud->lnum);
@@ -637,10 +639,7 @@ void dbg_dump_budg(struct ubifs_info *c)
         /* Print budgeting predictions */
         available = ubifs_calc_available(c, c->min_idx_lebs);
         outstanding = c->budg_data_growth + c->budg_dd_growth;
-        if (available > outstanding)
-                free = ubifs_reported_space(c, available - outstanding);
-        else
-                free = 0;
+        free = ubifs_get_free_space_nolock(c);
         printk(KERN_DEBUG "Budgeting predictions:\n");
         printk(KERN_DEBUG "\tavailable: %lld, outstanding %lld, free %lld\n",
                available, outstanding, free);
@@ -861,6 +860,65 @@ void dbg_dump_index(struct ubifs_info *c)
 }
 
 /**
+ * dbg_save_space_info - save information about flash space.
+ * @c: UBIFS file-system description object
+ *
+ * This function saves information about UBIFS free space, dirty space, etc, in
+ * order to check it later.
+ */
+void dbg_save_space_info(struct ubifs_info *c)
+{
+        struct ubifs_debug_info *d = c->dbg;
+
+        ubifs_get_lp_stats(c, &d->saved_lst);
+
+        spin_lock(&c->space_lock);
+        d->saved_free = ubifs_get_free_space_nolock(c);
+        spin_unlock(&c->space_lock);
+}
+
+/**
+ * dbg_check_space_info - check flash space information.
+ * @c: UBIFS file-system description object
+ *
+ * This function compares current flash space information with the information
+ * which was saved when the 'dbg_save_space_info()' function was called.
+ * Returns zero if the information has not changed, and %-EINVAL it it has
+ * changed.
+ */
+int dbg_check_space_info(struct ubifs_info *c)
+{
+        struct ubifs_debug_info *d = c->dbg;
+        struct ubifs_lp_stats lst;
+        long long avail, free;
+
+        spin_lock(&c->space_lock);
+        avail = ubifs_calc_available(c, c->min_idx_lebs);
+        spin_unlock(&c->space_lock);
+        free = ubifs_get_free_space(c);
+
+        if (free != d->saved_free) {
+                ubifs_err("free space changed from %lld to %lld",
+                          d->saved_free, free);
+                goto out;
+        }
+
+        return 0;
+
+out:
+        ubifs_msg("saved lprops statistics dump");
+        dbg_dump_lstats(&d->saved_lst);
+        ubifs_get_lp_stats(c, &lst);
+        ubifs_msg("current lprops statistics dump");
+        dbg_dump_lstats(&d->saved_lst);
+        spin_lock(&c->space_lock);
+        dbg_dump_budg(c);
+        spin_unlock(&c->space_lock);
+        dump_stack();
+        return -EINVAL;
+}
+
+/**
  * dbg_check_synced_i_size - check synchronized inode size.
  * @inode: inode to check
  *
@@ -2409,7 +2467,7 @@ void ubifs_debugging_exit(struct ubifs_info *c)
  * Root directory for UBIFS stuff in debugfs. Contains sub-directories which
  * contain the stuff specific to particular file-system mounts.
  */
-static struct dentry *debugfs_rootdir;
+static struct dentry *dfs_rootdir;
 
 /**
  * dbg_debugfs_init - initialize debugfs file-system.
@@ -2421,9 +2479,9 @@ static struct dentry *debugfs_rootdir;
  */
 int dbg_debugfs_init(void)
 {
-        debugfs_rootdir = debugfs_create_dir("ubifs", NULL);
-        if (IS_ERR(debugfs_rootdir)) {
-                int err = PTR_ERR(debugfs_rootdir);
+        dfs_rootdir = debugfs_create_dir("ubifs", NULL);
+        if (IS_ERR(dfs_rootdir)) {
+                int err = PTR_ERR(dfs_rootdir);
                 ubifs_err("cannot create \"ubifs\" debugfs directory, "
                           "error %d\n", err);
                 return err;
@@ -2437,7 +2495,7 @@ int dbg_debugfs_init(void)
  */
 void dbg_debugfs_exit(void)
 {
-        debugfs_remove(debugfs_rootdir);
+        debugfs_remove(dfs_rootdir);
 }
 
 static int open_debugfs_file(struct inode *inode, struct file *file)
@@ -2452,13 +2510,13 @@ static ssize_t write_debugfs_file(struct file *file, const char __user *buf,
         struct ubifs_info *c = file->private_data;
         struct ubifs_debug_info *d = c->dbg;
 
-        if (file->f_path.dentry == d->dump_lprops)
+        if (file->f_path.dentry == d->dfs_dump_lprops)
                 dbg_dump_lprops(c);
-        else if (file->f_path.dentry == d->dump_budg) {
+        else if (file->f_path.dentry == d->dfs_dump_budg) {
                 spin_lock(&c->space_lock);
                 dbg_dump_budg(c);
                 spin_unlock(&c->space_lock);
-        } else if (file->f_path.dentry == d->dump_tnc) {
+        } else if (file->f_path.dentry == d->dfs_dump_tnc) {
                 mutex_lock(&c->tnc_mutex);
                 dbg_dump_tnc(c);
                 mutex_unlock(&c->tnc_mutex);
@@ -2469,7 +2527,7 @@ static ssize_t write_debugfs_file(struct file *file, const char __user *buf,
         return count;
 }
 
-static const struct file_operations debugfs_fops = {
+static const struct file_operations dfs_fops = {
         .open = open_debugfs_file,
         .write = write_debugfs_file,
         .owner = THIS_MODULE,
@@ -2494,36 +2552,32 @@ int dbg_debugfs_init_fs(struct ubifs_info *c)
         struct dentry *dent;
         struct ubifs_debug_info *d = c->dbg;
 
-        sprintf(d->debugfs_dir_name, "ubi%d_%d", c->vi.ubi_num, c->vi.vol_id);
-        d->debugfs_dir = debugfs_create_dir(d->debugfs_dir_name,
-                                              debugfs_rootdir);
-        if (IS_ERR(d->debugfs_dir)) {
-                err = PTR_ERR(d->debugfs_dir);
+        sprintf(d->dfs_dir_name, "ubi%d_%d", c->vi.ubi_num, c->vi.vol_id);
+        d->dfs_dir = debugfs_create_dir(d->dfs_dir_name, dfs_rootdir);
+        if (IS_ERR(d->dfs_dir)) {
+                err = PTR_ERR(d->dfs_dir);
                 ubifs_err("cannot create \"%s\" debugfs directory, error %d\n",
-                          d->debugfs_dir_name, err);
+                          d->dfs_dir_name, err);
                 goto out;
         }
 
         fname = "dump_lprops";
-        dent = debugfs_create_file(fname, S_IWUGO, d->debugfs_dir, c,
-                                   &debugfs_fops);
+        dent = debugfs_create_file(fname, S_IWUGO, d->dfs_dir, c, &dfs_fops);
         if (IS_ERR(dent))
                 goto out_remove;
-        d->dump_lprops = dent;
+        d->dfs_dump_lprops = dent;
 
         fname = "dump_budg";
-        dent = debugfs_create_file(fname, S_IWUGO, d->debugfs_dir, c,
-                                   &debugfs_fops);
+        dent = debugfs_create_file(fname, S_IWUGO, d->dfs_dir, c, &dfs_fops);
         if (IS_ERR(dent))
                 goto out_remove;
-        d->dump_budg = dent;
+        d->dfs_dump_budg = dent;
 
         fname = "dump_tnc";
-        dent = debugfs_create_file(fname, S_IWUGO, d->debugfs_dir, c,
-                                   &debugfs_fops);
+        dent = debugfs_create_file(fname, S_IWUGO, d->dfs_dir, c, &dfs_fops);
         if (IS_ERR(dent))
                 goto out_remove;
-        d->dump_tnc = dent;
+        d->dfs_dump_tnc = dent;
 
         return 0;
 
@@ -2531,7 +2585,7 @@ out_remove:
         err = PTR_ERR(dent);
         ubifs_err("cannot create \"%s\" debugfs directory, error %d\n",
                   fname, err);
-        debugfs_remove_recursive(d->debugfs_dir);
+        debugfs_remove_recursive(d->dfs_dir);
 out:
         return err;
 }
@@ -2542,7 +2596,7 @@ out:
  */
 void dbg_debugfs_exit_fs(struct ubifs_info *c)
 {
-        debugfs_remove_recursive(c->dbg->debugfs_dir);
+        debugfs_remove_recursive(c->dbg->dfs_dir);
 }
 
 #endif /* CONFIG_UBIFS_FS_DEBUG */