jffs2: Erase pending blocks in GC pass, avoid invalid -EIO return

jffs2_garbage_collect_pass() would previously return -EAGAIN if it
couldn't find anything to garbage collect from, and there were blocks on
the erase_pending_list. If the blocks were actually in the process of
being erased, though, then they wouldn't be on that list. Check for
nr_erasing_blocks being non-zero instead.

Fix jffs2_reserve_space() to wait for the in-progress erases to
complete, when jffs2_garbage_collect_pass() returns -EAGAIN.

And fix jffs2_erase_succeeded() to actually wake up the erase_wait wq
that jffs2_reserve_space() is now using.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

3 files changed, 30 insertions, 4 deletions

diff --git a/fs/jffs2/erase.c b/fs/jffs2/erase.c
index b2d2b6a6e03e..563c857ca544 100644
--- a/fs/jffs2/erase.c
+++ b/fs/jffs2/erase.c
@@ -172,6 +172,7 @@ static void jffs2_erase_succeeded(struct jffs2_sb_info *c, struct jffs2_eraseblo
         mutex_unlock(&c->erase_free_sem);
         /* Ensure that kupdated calls us again to mark them clean */
         jffs2_erase_pending_trigger(c);
+        wake_up(&c->erase_wait);
 }
 
 static void jffs2_erase_failed(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t bad_offset)
diff --git a/fs/jffs2/gc.c b/fs/jffs2/gc.c
index 3b6f2fa12cff..1ea4a843a430 100644
--- a/fs/jffs2/gc.c
+++ b/fs/jffs2/gc.c
@@ -214,6 +214,19 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
                 return ret;
         }
 
+        /* If there are any blocks which need erasing, erase them now */
+        if (!list_empty(&c->erase_complete_list) ||
+            !list_empty(&c->erase_pending_list)) {
+                spin_unlock(&c->erase_completion_lock);
+                D1(printk(KERN_DEBUG "jffs2_garbage_collect_pass() erasing pending blocks\n"));
+                if (jffs2_erase_pending_blocks(c, 1)) {
+                        mutex_unlock(&c->alloc_sem);
+                        return 0;
+                }
+                D1(printk(KERN_DEBUG "No progress from erasing blocks; doing GC anyway\n"));
+                spin_lock(&c->erase_completion_lock);
+        }
+
         /* First, work out which block we're garbage-collecting */
         jeb = c->gcblock;
 
@@ -222,7 +235,7 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
 
         if (!jeb) {
                 /* Couldn't find a free block. But maybe we can just erase one and make 'progress'? */
-                if (!list_empty(&c->erase_pending_list)) {
+                if (c->nr_erasing_blocks) {
                         spin_unlock(&c->erase_completion_lock);
                         mutex_unlock(&c->alloc_sem);
                         return -EAGAIN;
diff --git a/fs/jffs2/nodemgmt.c b/fs/jffs2/nodemgmt.c
index 191359dde4e1..08e2c69fc147 100644
--- a/fs/jffs2/nodemgmt.c
+++ b/fs/jffs2/nodemgmt.c
@@ -116,9 +116,21 @@ int jffs2_reserve_space(struct jffs2_sb_info *c, uint32_t minsize,
 
                         ret = jffs2_garbage_collect_pass(c);
 
-                        if (ret == -EAGAIN)
-                                jffs2_erase_pending_blocks(c, 1);
-                        else if (ret)
+                        if (ret == -EAGAIN) {
+                                spin_lock(&c->erase_completion_lock);
+                                if (c->nr_erasing_blocks &&
+                                    list_empty(&c->erase_pending_list) &&
+                                    list_empty(&c->erase_complete_list)) {
+                                        DECLARE_WAITQUEUE(wait, current);
+                                        set_current_state(TASK_UNINTERRUPTIBLE);
+                                        add_wait_queue(&c->erase_wait, &wait);
+                                        D1(printk(KERN_DEBUG "%s waiting for erase to complete\n", __func__));
+                                        spin_unlock(&c->erase_completion_lock);
+
+                                        schedule();
+                                } else
+                                        spin_unlock(&c->erase_completion_lock);
+                        } else if (ret)
                                 return ret;
 
                         cond_resched();