nilfs2: introduce check flag to btree node buffer

nilfs_btree_get_block() now may return untested buffer due to
read-ahead.  This adds a new flag for buffer heads so that the btree
code can check whether the buffer is already verified or not.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

3 files changed, 15 insertions, 2 deletions

diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c
index 1b5321c0bcac..d3faa0bba171 100644
--- a/fs/nilfs2/btree.c
+++ b/fs/nilfs2/btree.c
@@ -370,8 +370,16 @@ static int nilfs_btree_node_broken(const struct nilfs_btree_node *node,
 
 int nilfs_btree_broken_node_block(struct buffer_head *bh)
 {
-        return nilfs_btree_node_broken((struct nilfs_btree_node *)bh->b_data,
+        int ret;
+
+        if (buffer_nilfs_checked(bh))
+                return 0;
+
+        ret = nilfs_btree_node_broken((struct nilfs_btree_node *)bh->b_data,
                                        bh->b_size, bh->b_blocknr);
+        if (likely(!ret))
+                set_buffer_nilfs_checked(bh);
+        return ret;
 }
 
 static struct nilfs_btree_node *
diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c
index 8de3e1e48130..aab11db2cb08 100644
--- a/fs/nilfs2/page.c
+++ b/fs/nilfs2/page.c
@@ -37,7 +37,8 @@
 
 #define NILFS_BUFFER_INHERENT_BITS  \
         ((1UL << BH_Uptodate) | (1UL << BH_Mapped) | (1UL << BH_NILFS_Node) | \
-         (1UL << BH_NILFS_Volatile) | (1UL << BH_NILFS_Allocated))
+         (1UL << BH_NILFS_Volatile) | (1UL << BH_NILFS_Allocated) | \
+         (1UL << BH_NILFS_Checked))
 
 static struct buffer_head *
 __nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index,
@@ -129,6 +130,7 @@ void nilfs_forget_buffer(struct buffer_head *bh)
 
         lock_buffer(bh);
         clear_buffer_nilfs_volatile(bh);
+        clear_buffer_nilfs_checked(bh);
         clear_buffer_dirty(bh);
         if (nilfs_page_buffers_clean(page))
                 __nilfs_clear_page_dirty(page);
@@ -480,6 +482,7 @@ void nilfs_clear_dirty_pages(struct address_space *mapping)
                                 lock_buffer(bh);
                                 clear_buffer_dirty(bh);
                                 clear_buffer_nilfs_volatile(bh);
+                                clear_buffer_nilfs_checked(bh);
                                 clear_buffer_uptodate(bh);
                                 clear_buffer_mapped(bh);
                                 unlock_buffer(bh);
diff --git a/fs/nilfs2/page.h b/fs/nilfs2/page.h
index 8abca4d1c1f8..f53d8da41ed7 100644
--- a/fs/nilfs2/page.h
+++ b/fs/nilfs2/page.h
@@ -34,11 +34,13 @@ enum {
         BH_NILFS_Allocated = BH_PrivateStart,
         BH_NILFS_Node,
         BH_NILFS_Volatile,
+        BH_NILFS_Checked,
 };
 
 BUFFER_FNS(NILFS_Allocated, nilfs_allocated)    /* nilfs private buffers */
 BUFFER_FNS(NILFS_Node, nilfs_node)              /* nilfs node buffers */
 BUFFER_FNS(NILFS_Volatile, nilfs_volatile)
+BUFFER_FNS(NILFS_Checked, nilfs_checked)        /* buffer is verified */
 
 
 void nilfs_mark_buffer_dirty(struct buffer_head *bh);