ocfs2: Validate metadata only when it's read from disk.

Add an optional validation hook to ocfs2_read_blocks().  Now the
validation function is only called when a block was actually read off of
disk.  It is not called when the buffer was in cache.

We add a buffer state bit BH_NeedsValidate to flag these buffers.  It
must always be one higher than the last JBD2 buffer state bit.

The dinode, dirblock, extent_block, and xattr_block validators are
lifted to this scheme directly.  The group_descriptor validator needs to
be split into two pieces.  The first part only needs the gd buffer and
is passed to ocfs2_read_block().  The second part requires the dinode as
well, and is called every time.  It's only 3 compares, so it's tiny.
This also allows us to clean up the non-fatal gd check used by resize.c.
It now has no magic argument.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 7 insertions, 8 deletions

diff --git a/fs/ocfs2/suballoc.h b/fs/ocfs2/suballoc.h
index 43de4fd826d3..e3c13c77f9e8 100644
--- a/fs/ocfs2/suballoc.h
+++ b/fs/ocfs2/suballoc.h
@@ -165,16 +165,15 @@ void ocfs2_free_ac_resource(struct ocfs2_alloc_context *ac);
 u64 ocfs2_which_cluster_group(struct inode *inode, u32 cluster);
 
 /*
- * By default, ocfs2_validate_group_descriptor() calls ocfs2_error() when it
+ * By default, ocfs2_read_group_descriptor() calls ocfs2_error() when it
  * finds a problem.  A caller that wants to check a group descriptor
- * without going readonly passes a nonzero clean_error.  This is only
- * resize, really.  Everyone else should be using
- * ocfs2_read_group_descriptor().
+ * without going readonly should read the block with ocfs2_read_block[s]()
+ * and then checking it with this function.  This is only resize, really.
+ * Everyone else should be using ocfs2_read_group_descriptor().
  */
-int ocfs2_validate_group_descriptor(struct super_block *sb,
-                                    struct ocfs2_dinode *di,
-                                    struct buffer_head *bh,
-                                    int clean_error);
+int ocfs2_check_group_descriptor(struct super_block *sb,
+                                 struct ocfs2_dinode *di,
+                                 struct buffer_head *bh);
 /*
  * Read a group descriptor block into *bh.  If *bh is NULL, a bh will be
  * allocated.  This is a cached read.  The descriptor will be validated with