[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, 2 insertions, 0 deletions

diff --git a/fs/jffs2/jffs2_fs_sb.h b/fs/jffs2/jffs2_fs_sb.h
index ae99cd7fd43b..3a2197f3c812 100644
--- a/fs/jffs2/jffs2_fs_sb.h
+++ b/fs/jffs2/jffs2_fs_sb.h
@@ -69,6 +69,8 @@ struct jffs2_sb_info {
         uint8_t resv_blocks_gctrigger;  /* ... wake up the GC thread */
         uint8_t resv_blocks_gcbad;      /* ... pick a block from the bad_list to GC */
         uint8_t resv_blocks_gcmerge;    /* ... merge pages when garbage collecting */
+        /* Number of 'very dirty' blocks before we trigger immediate GC */
+        uint8_t vdirty_blocks_gctrigger;
 
         uint32_t nospc_dirty_size;