1 files changed, 30 insertions, 6 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 719943763391..8fa3277f72dc 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -111,9 +111,10 @@ static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int creat
         unsigned char *mappage;
 
         if (page >= bitmap->pages) {
-                printk(KERN_ALERT
-                        "%s: invalid bitmap page request: %lu (> %lu)\n",
-                        bmname(bitmap), page, bitmap->pages-1);
+                /* This can happen if bitmap_start_sync goes beyond
+                 * End-of-device while looking for a whole page.
+                 * It is harmless.
+                 */
                 return -EINVAL;
         }
 
@@ -570,7 +571,7 @@ static int bitmap_read_sb(struct bitmap *bitmap)
         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
                 reason = "unrecognized superblock version";
-        else if (chunksize < PAGE_SIZE)
+        else if (chunksize < 512)
                 reason = "bitmap chunksize too small";
         else if ((1 << ffz(~chunksize)) != chunksize)
                 reason = "bitmap chunksize not a power of 2";
@@ -1345,8 +1346,8 @@ void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long secto
         }
 }
 
-int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
-                        int degraded)
+static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
+                               int degraded)
 {
         bitmap_counter_t *bmc;
         int rv;
@@ -1374,6 +1375,29 @@ int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
         return rv;
 }
 
+int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
+                      int degraded)
+{
+        /* bitmap_start_sync must always report on multiples of whole
+         * pages, otherwise resync (which is very PAGE_SIZE based) will
+         * get confused.
+         * So call __bitmap_start_sync repeatedly (if needed) until
+         * At least PAGE_SIZE>>9 blocks are covered.
+         * Return the 'or' of the result.
+         */
+        int rv = 0;
+        int blocks1;
+
+        *blocks = 0;
+        while (*blocks < (PAGE_SIZE>>9)) {
+                rv |= __bitmap_start_sync(bitmap, offset,
+                                          &blocks1, degraded);
+                offset += blocks1;
+                *blocks += blocks1;
+        }
+        return rv;
+}
+
 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
 {
         bitmap_counter_t *bmc;