1 files changed, 64 insertions, 13 deletions

diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index 9443896ede07..7035582786fb 100644
--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -145,8 +145,9 @@ int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type)
 EXPORT_SYMBOL(dm_dirty_log_type_unregister);
 
 struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
-                                         struct dm_target *ti,
-                                         unsigned int argc, char **argv)
+                        struct dm_target *ti,
+                        int (*flush_callback_fn)(struct dm_target *ti),
+                        unsigned int argc, char **argv)
 {
         struct dm_dirty_log_type *type;
         struct dm_dirty_log *log;
@@ -161,6 +162,7 @@ struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
                 return NULL;
         }
 
+        log->flush_callback_fn = flush_callback_fn;
         log->type = type;
         if (type->ctr(log, ti, argc, argv)) {
                 kfree(log);
@@ -208,7 +210,9 @@ struct log_header {
 
 struct log_c {
         struct dm_target *ti;
-        int touched;
+        int touched_dirtied;
+        int touched_cleaned;
+        int flush_failed;
         uint32_t region_size;
         unsigned int region_count;
         region_t sync_count;
@@ -233,6 +237,7 @@ struct log_c {
          * Disk log fields
          */
         int log_dev_failed;
+        int log_dev_flush_failed;
         struct dm_dev *log_dev;
         struct log_header header;
 
@@ -253,14 +258,14 @@ static inline void log_set_bit(struct log_c *l,
                                uint32_t *bs, unsigned bit)
 {
         ext2_set_bit(bit, (unsigned long *) bs);
-        l->touched = 1;
+        l->touched_cleaned = 1;
 }
 
 static inline void log_clear_bit(struct log_c *l,
                                  uint32_t *bs, unsigned bit)
 {
         ext2_clear_bit(bit, (unsigned long *) bs);
-        l->touched = 1;
+        l->touched_dirtied = 1;
 }
 
 /*----------------------------------------------------------------
@@ -287,6 +292,19 @@ static int rw_header(struct log_c *lc, int rw)
         return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
 }
 
+static int flush_header(struct log_c *lc)
+{
+        struct dm_io_region null_location = {
+                .bdev = lc->header_location.bdev,
+                .sector = 0,
+                .count = 0,
+        };
+
+        lc->io_req.bi_rw = WRITE_BARRIER;
+
+        return dm_io(&lc->io_req, 1, &null_location, NULL);
+}
+
 static int read_header(struct log_c *log)
 {
         int r;
@@ -378,7 +396,9 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
         }
 
         lc->ti = ti;
-        lc->touched = 0;
+        lc->touched_dirtied = 0;
+        lc->touched_cleaned = 0;
+        lc->flush_failed = 0;
         lc->region_size = region_size;
         lc->region_count = region_count;
         lc->sync = sync;
@@ -406,6 +426,7 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
         } else {
                 lc->log_dev = dev;
                 lc->log_dev_failed = 0;
+                lc->log_dev_flush_failed = 0;
                 lc->header_location.bdev = lc->log_dev->bdev;
                 lc->header_location.sector = 0;
 
@@ -614,6 +635,11 @@ static int disk_resume(struct dm_dirty_log *log)
 
         /* write the new header */
         r = rw_header(lc, WRITE);
+        if (!r) {
+                r = flush_header(lc);
+                if (r)
+                        lc->log_dev_flush_failed = 1;
+        }
         if (r) {
                 DMWARN("%s: Failed to write header on dirty region log device",
                        lc->log_dev->name);
@@ -656,18 +682,40 @@ static int core_flush(struct dm_dirty_log *log)
 
 static int disk_flush(struct dm_dirty_log *log)
 {
-        int r;
-        struct log_c *lc = (struct log_c *) log->context;
+        int r, i;
+        struct log_c *lc = log->context;
 
         /* only write if the log has changed */
-        if (!lc->touched)
+        if (!lc->touched_cleaned && !lc->touched_dirtied)
                 return 0;
 
+        if (lc->touched_cleaned && log->flush_callback_fn &&
+            log->flush_callback_fn(lc->ti)) {
+                /*
+                 * At this point it is impossible to determine which
+                 * regions are clean and which are dirty (without
+                 * re-reading the log off disk). So mark all of them
+                 * dirty.
+                 */
+                lc->flush_failed = 1;
+                for (i = 0; i < lc->region_count; i++)
+                        log_clear_bit(lc, lc->clean_bits, i);
+        }
+
         r = rw_header(lc, WRITE);
         if (r)
                 fail_log_device(lc);
-        else
-                lc->touched = 0;
+        else {
+                if (lc->touched_dirtied) {
+                        r = flush_header(lc);
+                        if (r) {
+                                lc->log_dev_flush_failed = 1;
+                                fail_log_device(lc);
+                        } else
+                                lc->touched_dirtied = 0;
+                }
+                lc->touched_cleaned = 0;
+        }
 
         return r;
 }
@@ -681,7 +729,8 @@ static void core_mark_region(struct dm_dirty_log *log, region_t region)
 static void core_clear_region(struct dm_dirty_log *log, region_t region)
 {
         struct log_c *lc = (struct log_c *) log->context;
-        log_set_bit(lc, lc->clean_bits, region);
+        if (likely(!lc->flush_failed))
+                log_set_bit(lc, lc->clean_bits, region);
 }
 
 static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
@@ -762,7 +811,9 @@ static int disk_status(struct dm_dirty_log *log, status_type_t status,
         switch(status) {
         case STATUSTYPE_INFO:
                 DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
-                       lc->log_dev_failed ? 'D' : 'A');
+                       lc->log_dev_flush_failed ? 'F' :
+                       lc->log_dev_failed ? 'D' :
+                       'A');
                 break;
 
         case STATUSTYPE_TABLE: