dm snapshot: fix hung bios when copy error occurs

[pandora-kernel.git] / drivers / md / dm-snap-persistent.c

diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index 3ac4156..6215f34 100644 (file)
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -269,6 +269,14 @@ static chunk_t area_location(struct pstore *ps, chunk_t area)
        return NUM_SNAPSHOT_HDR_CHUNKS + ((ps->exceptions_per_area + 1) * area);
 }
 
+static void skip_metadata(struct pstore *ps)
+{
+       uint32_t stride = ps->exceptions_per_area + 1;
+       chunk_t next_free = ps->next_free;
+       if (sector_div(next_free, stride) == NUM_SNAPSHOT_HDR_CHUNKS)
+               ps->next_free++;
+}
+
 /*
  * Read or write a metadata area.  Remembering to skip the first
  * chunk which holds the header.
@@ -502,6 +510,8 @@ static int read_exceptions(struct pstore *ps,
 
        ps->current_area--;
 
+       skip_metadata(ps);
+
        return 0;
 }
 
@@ -616,8 +626,6 @@ static int persistent_prepare_exception(struct dm_exception_store *store,
                                        struct dm_exception *e)
 {
        struct pstore *ps = get_info(store);
-       uint32_t stride;
-       chunk_t next_free;
        sector_t size = get_dev_size(dm_snap_cow(store->snap)->bdev);
 
        /* Is there enough room ? */
@@ -630,17 +638,15 @@ static int persistent_prepare_exception(struct dm_exception_store *store,
         * Move onto the next free pending, making sure to take
         * into account the location of the metadata chunks.
         */
-       stride = (ps->exceptions_per_area + 1);
-       next_free = ++ps->next_free;
-       if (sector_div(next_free, stride) == 1)
-               ps->next_free++;
+       ps->next_free++;
+       skip_metadata(ps);
 
        atomic_inc(&ps->pending_count);
        return 0;
 }
 
 static void persistent_commit_exception(struct dm_exception_store *store,
-                                       struct dm_exception *e,
+                                       struct dm_exception *e, int valid,
                                        void (*callback) (void *, int success),
                                        void *callback_context)
 {
@@ -649,6 +655,9 @@ static void persistent_commit_exception(struct dm_exception_store *store,
        struct core_exception ce;
        struct commit_callback *cb;
 
+       if (!valid)
+               ps->valid = 0;
+
        ce.old_chunk = e->old_chunk;
        ce.new_chunk = e->new_chunk;
        write_exception(ps, ps->current_committed++, &ce);