1 files changed, 44 insertions, 19 deletions

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index f9e2cd8cf711..a2cff2b9d5b5 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -336,10 +336,10 @@ err_out:
  * Return buffer_head on success or NULL in case of failure.
  */
 struct buffer_head *
-ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
+ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
 {
         struct ext4_group_desc *desc;
-        struct buffer_head *bh = NULL;
+        struct buffer_head *bh;
         ext4_fsblk_t bitmap_blk;
 
         desc = ext4_get_group_desc(sb, block_group, NULL);
@@ -348,9 +348,9 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
         bitmap_blk = ext4_block_bitmap(sb, desc);
         bh = sb_getblk(sb, bitmap_blk);
         if (unlikely(!bh)) {
-                ext4_error(sb, "Cannot read block bitmap - "
-                            "block_group = %u, block_bitmap = %llu",
-                            block_group, bitmap_blk);
+                ext4_error(sb, "Cannot get buffer for block bitmap - "
+                           "block_group = %u, block_bitmap = %llu",
+                           block_group, bitmap_blk);
                 return NULL;
         }
 
@@ -382,25 +382,50 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
                 return bh;
         }
         /*
-         * submit the buffer_head for read. We can
-         * safely mark the bitmap as uptodate now.
-         * We do it here so the bitmap uptodate bit
-         * get set with buffer lock held.
+         * submit the buffer_head for reading
          */
+        set_buffer_new(bh);
         trace_ext4_read_block_bitmap_load(sb, block_group);
-        set_bitmap_uptodate(bh);
-        if (bh_submit_read(bh) < 0) {
-                put_bh(bh);
+        bh->b_end_io = ext4_end_bitmap_read;
+        get_bh(bh);
+        submit_bh(READ, bh);
+        return bh;
+}
+
+/* Returns 0 on success, 1 on error */
+int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
+                           struct buffer_head *bh)
+{
+        struct ext4_group_desc *desc;
+
+        if (!buffer_new(bh))
+                return 0;
+        desc = ext4_get_group_desc(sb, block_group, NULL);
+        if (!desc)
+                return 1;
+        wait_on_buffer(bh);
+        if (!buffer_uptodate(bh)) {
                 ext4_error(sb, "Cannot read block bitmap - "
-                            "block_group = %u, block_bitmap = %llu",
-                            block_group, bitmap_blk);
-                return NULL;
+                           "block_group = %u, block_bitmap = %llu",
+                           block_group, bh->b_blocknr);
+                return 1;
         }
+        clear_buffer_new(bh);
+        /* Panic or remount fs read-only if block bitmap is invalid */
         ext4_valid_block_bitmap(sb, desc, block_group, bh);
-        /*
-         * file system mounted not to panic on error,
-         * continue with corrupt bitmap
-         */
+        return 0;
+}
+
+struct buffer_head *
+ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
+{
+        struct buffer_head *bh;
+
+        bh = ext4_read_block_bitmap_nowait(sb, block_group);
+        if (ext4_wait_block_bitmap(sb, block_group, bh)) {
+                put_bh(bh);
+                return NULL;
+        }
         return bh;
 }