UBIFS: fix LPT out-of-space bug (again)

The function to traverse and dirty the LPT was still not
dirtying all nodes, with the result that the LPT could
run out of space.

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 32 insertions, 12 deletions

diff --git a/fs/ubifs/lpt_commit.c b/fs/ubifs/lpt_commit.c
index 96ca95707175..3216a1f277f8 100644
--- a/fs/ubifs/lpt_commit.c
+++ b/fs/ubifs/lpt_commit.c
@@ -556,23 +556,23 @@ no_space:
 }
 
 /**
- * next_pnode - find next pnode.
+ * next_pnode_to_dirty - find next pnode to dirty.
  * @c: UBIFS file-system description object
  * @pnode: pnode
  *
- * This function returns the next pnode or %NULL if there are no more pnodes.
+ * This function returns the next pnode to dirty or %NULL if there are no more
+ * pnodes.  Note that pnodes that have never been written (lnum == 0) are
+ * skipped.
  */
-static struct ubifs_pnode *next_pnode(struct ubifs_info *c,
-                                      struct ubifs_pnode *pnode)
+static struct ubifs_pnode *next_pnode_to_dirty(struct ubifs_info *c,
+                                               struct ubifs_pnode *pnode)
 {
         struct ubifs_nnode *nnode;
         int iip;
 
         /* Try to go right */
         nnode = pnode->parent;
-        iip = pnode->iip + 1;
-        if (iip < UBIFS_LPT_FANOUT) {
-                /* We assume here that LEB zero is never an LPT LEB */
+        for (iip = pnode->iip + 1; iip < UBIFS_LPT_FANOUT; iip++) {
                 if (nnode->nbranch[iip].lnum)
                         return ubifs_get_pnode(c, nnode, iip);
         }
@@ -583,8 +583,11 @@ static struct ubifs_pnode *next_pnode(struct ubifs_info *c,
                 nnode = nnode->parent;
                 if (!nnode)
                         return NULL;
-                /* We assume here that LEB zero is never an LPT LEB */
-        } while (iip >= UBIFS_LPT_FANOUT || !nnode->nbranch[iip].lnum);
+                for (; iip < UBIFS_LPT_FANOUT; iip++) {
+                        if (nnode->nbranch[iip].lnum)
+                                break;
+                }
+       } while (iip >= UBIFS_LPT_FANOUT);
 
         /* Go right */
         nnode = ubifs_get_nnode(c, nnode, iip);
@@ -593,12 +596,29 @@ static struct ubifs_pnode *next_pnode(struct ubifs_info *c,
 
         /* Go down to level 1 */
         while (nnode->level > 1) {
-                nnode = ubifs_get_nnode(c, nnode, 0);
+                for (iip = 0; iip < UBIFS_LPT_FANOUT; iip++) {
+                        if (nnode->nbranch[iip].lnum)
+                                break;
+                }
+                if (iip >= UBIFS_LPT_FANOUT) {
+                        /*
+                         * Should not happen, but we need to keep going
+                         * if it does.
+                         */
+                        iip = 0;
+                }
+                nnode = ubifs_get_nnode(c, nnode, iip);
                 if (IS_ERR(nnode))
                         return (void *)nnode;
         }
 
-        return ubifs_get_pnode(c, nnode, 0);
+        for (iip = 0; iip < UBIFS_LPT_FANOUT; iip++)
+                if (nnode->nbranch[iip].lnum)
+                        break;
+        if (iip >= UBIFS_LPT_FANOUT)
+                /* Should not happen, but we need to keep going if it does */
+                iip = 0;
+        return ubifs_get_pnode(c, nnode, iip);
 }
 
 /**
@@ -688,7 +708,7 @@ static int make_tree_dirty(struct ubifs_info *c)
         pnode = pnode_lookup(c, 0);
         while (pnode) {
                 do_make_pnode_dirty(c, pnode);
-                pnode = next_pnode(c, pnode);
+                pnode = next_pnode_to_dirty(c, pnode);
                 if (IS_ERR(pnode))
                         return PTR_ERR(pnode);
         }