[PATCH] JFFS2 appears to "freeze" during erase

[Joakim Tjernlund]

On Mon, 2007-06-04 at 11:20 +0200, Joakim Tjernlund wrote:
> On Fri, 2007-06-01 at 19:04 +0100, David Woodhouse wrote:
> > On Fri, 2007-06-01 at 11:51 +0200, Joakim Tjernlund wrote:
> > > This is a old patch from Radoslaw Bisewski(see MTD list). The patch
> > > fixes the long stalls I am seeing in "GC starves write's in 2.6.20" I
> > > sent yesterday. Please apply.
> > 
> > It seems to make sense; I need to convince myself that every other user
> > of the erase_free_sem is actually OK with it. I think
> > jffs2_g_c_deletion_dirent() should be OK, at first glance. I'm less
> > convinced about jffs2_mark_node_obsolete(), where we currently hold the
> > erase_free_sem while we actually mark the node obsolete. Will look into
> > it...
> > 
> 
> looked a litte closer on the new locking in erase.c and wonder
> why not jffs2_erase_succeeded() and jffs2_erase_failed() needs
> to take erase_free_sem?
> 
>  Jocke

Found another bug, here is an addon diff. Also added erase_free_sem to
jffs2_erase_succeeded() and jffs2_erase_failed() as I think it should
take the erase_free_sem there too.

 Jocke

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund at transmode.se>
---

diff --git a/fs/jffs2/erase.c b/fs/jffs2/erase.c
index 5b5c291..45b9f3e 100644
--- a/fs/jffs2/erase.c
+++ b/fs/jffs2/erase.c
@@ -93,6 +93,7 @@ static void jffs2_erase_block(struct jffs2_sb_info *c,
 		c->dirty_size += c->sector_size;
 		jeb->dirty_size = c->sector_size;
 		spin_unlock(&c->erase_completion_lock);
+		up(&c->erase_free_sem);
 		return;
 	}
 
@@ -163,9 +164,11 @@ void jffs2_erase_pending_blocks(struct jffs2_sb_info *c, int count)
 static void jffs2_erase_succeeded(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
 {
 	D1(printk(KERN_DEBUG "Erase completed successfully at 0x%08x\n", jeb->offset));
+	down(&c->erase_free_sem);
 	spin_lock(&c->erase_completion_lock);
 	list_move_tail(&jeb->list, &c->erase_complete_list);
 	spin_unlock(&c->erase_completion_lock);
+	up(&c->erase_free_sem);
 	/* Ensure that kupdated calls us again to mark them clean */
 	jffs2_erase_pending_trigger(c);
 }
@@ -179,22 +182,26 @@ static void jffs2_erase_failed(struct jffs2_sb_info *c, struct jffs2_eraseblock
 		   failed too many times. */
 		if (!jffs2_write_nand_badblock(c, jeb, bad_offset)) {
 			/* We'd like to give this block another try. */
+			down(&c->erase_free_sem);
 			spin_lock(&c->erase_completion_lock);
 			list_move(&jeb->list, &c->erase_pending_list);
 			c->erasing_size -= c->sector_size;
 			c->dirty_size += c->sector_size;
 			jeb->dirty_size = c->sector_size;
 			spin_unlock(&c->erase_completion_lock);
+			up(&c->erase_free_sem);
 			return;
 		}
 	}
 
+	down(&c->erase_free_sem);
 	spin_lock(&c->erase_completion_lock);
 	c->erasing_size -= c->sector_size;
 	c->bad_size += c->sector_size;
 	list_move(&jeb->list, &c->bad_list);
 	c->nr_erasing_blocks--;
 	spin_unlock(&c->erase_completion_lock);
+	up(&c->erase_free_sem);
 	wake_up(&c->erase_wait);
 }