Merge tag 'upstream-3.18-rc1-v2' of git://git.infradead.org/linux-ubifs

Pull UBI/UBIFS fixes from Artem Bityutskiy:
 - fix for a theoretical race condition which could lead to a situation
   when UBIFS is unable to mount a file-system (Hujianyang)
 - a few fixes for the ubiblock sybsystem, error path fixes
 - the ubiblock subsystem has had the volume size change handling
   improved
 - a few fixes and nicifications in the fastmap subsystem

* tag 'upstream-3.18-rc1-v2' of git://git.infradead.org/linux-ubifs:
  UBI: Fastmap: Calc fastmap size correctly
  UBIFS: Fix trivial typo in power_cut_emulated()
  UBI: Fix trivial typo in __schedule_ubi_work
  UBI: wl: Rename cancel flag to shutdown
  UBI: ubi_eba_read_leb: Remove in vain variable assignment
  UBIFS: Align the dump messages of SB_NODE
  UBI: Fix livelock in produce_free_peb()
  UBI: return on error in rename_volumes()
  UBI: Improve comment on work_sem
  UBIFS: Remove bogus assert
  UBI: Dispatch update notification if the volume is updated
  UBI: block: Add support for the UBI_VOLUME_UPDATED notification
  UBI: block: Fix block device size setting
  UBI: block: fix dereference on uninitialized dev
  UBI: add missing kmem_cache_free() in process_pool_aeb error path
  UBIFS: fix free log space calculation
  UBIFS: fix a race condition

1 files changed, 14 insertions, 5 deletions

diff --git a/fs/ubifs/log.c b/fs/ubifs/log.c
index a47ddfc9be6b..c14628fbeee2 100644
--- a/fs/ubifs/log.c
+++ b/fs/ubifs/log.c
@@ -106,10 +106,14 @@ static inline long long empty_log_bytes(const struct ubifs_info *c)
 	h = (long long)c->lhead_lnum * c->leb_size + c->lhead_offs;
 	t = (long long)c->ltail_lnum * c->leb_size;
 
-	if (h >= t)
+	if (h > t)
 		return c->log_bytes - h + t;
-	else
+	else if (h != t)
 		return t - h;
+	else if (c->lhead_lnum != c->ltail_lnum)
+		return 0;
+	else
+		return c->log_bytes;
 }
 
 /**
@@ -447,9 +451,9 @@ out:
  * @ltail_lnum: new log tail LEB number
  *
  * This function is called on when the commit operation was finished. It
- * moves log tail to new position and unmaps LEBs which contain obsolete data.
- * Returns zero in case of success and a negative error code in case of
- * failure.
+ * moves log tail to new position and updates the master node so that it stores
+ * the new log tail LEB number. Returns zero in case of success and a negative
+ * error code in case of failure.
  */
 int ubifs_log_end_commit(struct ubifs_info *c, int ltail_lnum)
 {
@@ -477,7 +481,12 @@ int ubifs_log_end_commit(struct ubifs_info *c, int ltail_lnum)
 	spin_unlock(&c->buds_lock);
 
 	err = dbg_check_bud_bytes(c);
+	if (err)
+		goto out;
 
+	err = ubifs_write_master(c);
+
+out:
 	mutex_unlock(&c->log_mutex);
 	return err;
 }