[JFFS2] Trigger garbage collection when very_dirty_list size becomes excessive

With huge amounts of free space, we weren't bothering to GC for while a
while, and pathological numbers of obsolete nodes were accumulating,
seriously affecting performance on NAND flash (OLPC trac #3978)

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 12 insertions, 2 deletions

diff --git a/fs/jffs2/nodemgmt.c b/fs/jffs2/nodemgmt.c
index 5b49bff364b4..1b79534e9d48 100644
--- a/fs/jffs2/nodemgmt.c
+++ b/fs/jffs2/nodemgmt.c
@@ -722,6 +722,8 @@ int jffs2_thread_should_wake(struct jffs2_sb_info *c)
 {
         int ret = 0;
         uint32_t dirty;
+        int nr_very_dirty = 0;
+        struct jffs2_eraseblock *jeb;
 
         if (c->unchecked_size) {
                 D1(printk(KERN_DEBUG "jffs2_thread_should_wake(): unchecked_size %d, checked_ino #%d\n",
@@ -743,8 +745,16 @@ int jffs2_thread_should_wake(struct jffs2_sb_info *c)
                         (dirty > c->nospc_dirty_size))
                 ret = 1;
 
-        D1(printk(KERN_DEBUG "jffs2_thread_should_wake(): nr_free_blocks %d, nr_erasing_blocks %d, dirty_size 0x%x: %s\n",
-                  c->nr_free_blocks, c->nr_erasing_blocks, c->dirty_size, ret?"yes":"no"));
+        list_for_each_entry(jeb, &c->very_dirty_list, list) {
+                nr_very_dirty++;
+                if (nr_very_dirty == c->vdirty_blocks_gctrigger) {
+                        ret = 1;
+                        D1(break);
+                }
+        }
+
+        D1(printk(KERN_DEBUG "jffs2_thread_should_wake(): nr_free_blocks %d, nr_erasing_blocks %d, dirty_size 0x%x, vdirty_blocks %d: %s\n",
+                  c->nr_free_blocks, c->nr_erasing_blocks, c->dirty_size, nr_very_dirty, ret?"yes":"no"));
 
         return ret;
 }