UBIFS: add a commentary about log recovery

Add a commentary which elaborates that 'ubifs_recover_log_leb()' recovers only
the last log LEB, not any. Also remove some unneeded newlines.

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

diff --git a/fs/ubifs/recovery.c b/fs/ubifs/recovery.c
index c902a5d..77e9b87 100644 (file)
--- a/fs/ubifs/recovery.c
+++ b/fs/ubifs/recovery.c
@@ -772,7 +772,8 @@ out_free:
  * @sbuf: LEB-sized buffer to use
  *
  * This function does a scan of a LEB, but caters for errors that might have
- * been caused by the unclean unmount from which we are attempting to recover.
+ * been caused by unclean reboots from which we are attempting to recover
+ * (assume that only the last log LEB can be corrupted by an unclean reboot).
  *
  * This function returns %0 on success and a negative error code on failure.
  */

diff --git a/fs/ubifs/replay.c b/fs/ubifs/replay.c
index 730598c..7df04ba 100644 (file)
--- a/fs/ubifs/replay.c
+++ b/fs/ubifs/replay.c
@@ -839,6 +839,11 @@ static int replay_log_leb(struct ubifs_info *c, int lnum, int offs, void *sbuf)
        if (IS_ERR(sleb)) {
                if (PTR_ERR(sleb) != -EUCLEAN || !c->need_recovery)
                        return PTR_ERR(sleb);
+               /*
+                * Note, the below function will recover this log LEB only if
+                * it is the last, because unclean reboots can possibly corrupt
+                * only the tail of the log.
+                */
                sleb = ubifs_recover_log_leb(c, lnum, offs, sbuf);
                if (IS_ERR(sleb))
                        return PTR_ERR(sleb);
@@ -850,7 +855,6 @@ static int replay_log_leb(struct ubifs_info *c, int lnum, int offs, void *sbuf)
        }
 
        node = sleb->buf;
-
        snod = list_entry(sleb->nodes.next, struct ubifs_scan_node, list);
        if (c->cs_sqnum == 0) {
                /*
@@ -897,7 +901,6 @@ static int replay_log_leb(struct ubifs_info *c, int lnum, int offs, void *sbuf)
        }
 
        list_for_each_entry(snod, &sleb->nodes, list) {
-
                cond_resched();
 
                if (snod->sqnum >= SQNUM_WATERMARK) {
@@ -1030,9 +1033,7 @@ int ubifs_replay_journal(struct ubifs_info *c)
                return -ENOMEM;
 
        dbg_mnt("start replaying the journal");
-
        c->replaying = 1;
-
        lnum = c->ltail_lnum = c->lhead_lnum;
        offs = c->lhead_offs;