ocfs2: Morph the haphazard OCFS2_IS_VALID_DINODE() checks.

Random places in the code would check a dinode bh to see if it was
valid.  Not only did they do different levels of validation, they
handled errors in different ways.

The previous commit unified inode block reads, validating all block
reads in the same place.  Thus, these haphazard checks are no longer
necessary.  Rather than eliminate them, however, we change them to
BUG_ON() checks.  This ensures the assumptions remain true.  All of the
code paths to these checks have been audited to ensure they come from a
validated inode read.

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

1 files changed, 16 insertions, 20 deletions

diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index c5ff18b46b57..95d432b694e4 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -441,11 +441,11 @@ static int ocfs2_reserve_suballoc_bits(struct ocfs2_super *osb,
 	ac->ac_alloc_slot = slot;
 
 	fe = (struct ocfs2_dinode *) bh->b_data;
-	if (!OCFS2_IS_VALID_DINODE(fe)) {
-		OCFS2_RO_ON_INVALID_DINODE(alloc_inode->i_sb, fe);
-		status = -EIO;
-		goto bail;
-	}
+
+	/* The bh was validated by the inode read inside
+	 * ocfs2_inode_lock().  Any corruption is a code bug. */
+	BUG_ON(!OCFS2_IS_VALID_DINODE(fe));
+
 	if (!(fe->i_flags & cpu_to_le32(OCFS2_CHAIN_FL))) {
 		ocfs2_error(alloc_inode->i_sb, "Invalid chain allocator %llu",
 			    (unsigned long long)le64_to_cpu(fe->i_blkno));
@@ -931,11 +931,6 @@ static int ocfs2_relink_block_group(handle_t *handle,
 	struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) bg_bh->b_data;
 	struct ocfs2_group_desc *prev_bg = (struct ocfs2_group_desc *) prev_bg_bh->b_data;
 
-	if (!OCFS2_IS_VALID_DINODE(fe)) {
-		OCFS2_RO_ON_INVALID_DINODE(alloc_inode->i_sb, fe);
-		status = -EIO;
-		goto out;
-	}
 	if (!OCFS2_IS_VALID_GROUP_DESC(bg)) {
 		OCFS2_RO_ON_INVALID_GROUP_DESC(alloc_inode->i_sb, bg);
 		status = -EIO;
@@ -1392,11 +1387,11 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
 	BUG_ON(!ac->ac_bh);
 
 	fe = (struct ocfs2_dinode *) ac->ac_bh->b_data;
-	if (!OCFS2_IS_VALID_DINODE(fe)) {
-		OCFS2_RO_ON_INVALID_DINODE(osb->sb, fe);
-		status = -EIO;
-		goto bail;
-	}
+
+	/* The bh was validated by the inode read during
+	 * ocfs2_reserve_suballoc_bits().  Any corruption is a code bug. */
+	BUG_ON(!OCFS2_IS_VALID_DINODE(fe));
+
 	if (le32_to_cpu(fe->id1.bitmap1.i_used) >=
 	    le32_to_cpu(fe->id1.bitmap1.i_total)) {
 		ocfs2_error(osb->sb, "Chain allocator dinode %llu has %u used "
@@ -1782,11 +1777,12 @@ int ocfs2_free_suballoc_bits(handle_t *handle,
 
 	mlog_entry_void();
 
-	if (!OCFS2_IS_VALID_DINODE(fe)) {
-		OCFS2_RO_ON_INVALID_DINODE(alloc_inode->i_sb, fe);
-		status = -EIO;
-		goto bail;
-	}
+	/* The alloc_bh comes from ocfs2_free_dinode() or
+	 * ocfs2_free_clusters().  The callers have all locked the
+	 * allocator and gotten alloc_bh from the lock call.  This
+	 * validates the dinode buffer.  Any corruption that has happended
+	 * is a code bug. */
+	BUG_ON(!OCFS2_IS_VALID_DINODE(fe));
 	BUG_ON((count + start_bit) > ocfs2_bits_per_group(cl));
 
 	mlog(0, "%llu: freeing %u bits from group %llu, starting at %u\n",