1 files changed, 119 insertions, 172 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 3e1529c39808..0e28c749e273 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -83,6 +83,86 @@ static struct buffer_head *ext4_append(handle_t *handle,
 	return bh;
 }
 
+static int ext4_dx_csum_verify(struct inode *inode,
+			       struct ext4_dir_entry *dirent);
+
+typedef enum {
+	EITHER, INDEX, DIRENT
+} dirblock_type_t;
+
+#define ext4_read_dirblock(inode, block, type) \
+	__ext4_read_dirblock((inode), (block), (type), __LINE__)
+
+static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
+					      ext4_lblk_t block,
+					      dirblock_type_t type,
+					      unsigned int line)
+{
+	struct buffer_head *bh;
+	struct ext4_dir_entry *dirent;
+	int err = 0, is_dx_block = 0;
+
+	bh = ext4_bread(NULL, inode, block, 0, &err);
+	if (!bh) {
+		if (err == 0) {
+			ext4_error_inode(inode, __func__, line, block,
+					       "Directory hole found");
+			return ERR_PTR(-EIO);
+		}
+		__ext4_warning(inode->i_sb, __func__, line,
+			       "error reading directory block "
+			       "(ino %lu, block %lu)", inode->i_ino,
+			       (unsigned long) block);
+		return ERR_PTR(err);
+	}
+	dirent = (struct ext4_dir_entry *) bh->b_data;
+	/* Determine whether or not we have an index block */
+	if (is_dx(inode)) {
+		if (block == 0)
+			is_dx_block = 1;
+		else if (ext4_rec_len_from_disk(dirent->rec_len,
+						inode->i_sb->s_blocksize) ==
+			 inode->i_sb->s_blocksize)
+			is_dx_block = 1;
+	}
+	if (!is_dx_block && type == INDEX) {
+		ext4_error_inode(inode, __func__, line, block,
+		       "directory leaf block found instead of index block");
+		return ERR_PTR(-EIO);
+	}
+	if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) ||
+	    buffer_verified(bh))
+		return bh;
+
+	/*
+	 * An empty leaf block can get mistaken for a index block; for
+	 * this reason, we can only check the index checksum when the
+	 * caller is sure it should be an index block.
+	 */
+	if (is_dx_block && type == INDEX) {
+		if (ext4_dx_csum_verify(inode, dirent))
+			set_buffer_verified(bh);
+		else {
+			ext4_error_inode(inode, __func__, line, block,
+				"Directory index failed checksum");
+			brelse(bh);
+			return ERR_PTR(-EIO);
+		}
+	}
+	if (!is_dx_block) {
+		if (ext4_dirent_csum_verify(inode, dirent))
+			set_buffer_verified(bh);
+		else {
+			ext4_error_inode(inode, __func__, line, block,
+				"Directory block failed checksum");
+			brelse(bh);
+			return ERR_PTR(-EIO);
+		}
+	}
+	return bh;
+}
+
 #ifndef assert
 #define assert(test) J_ASSERT(test)
 #endif
@@ -604,9 +684,9 @@ dx_probe(const struct qstr *d_name, struct inode *dir,
 	u32 hash;
 
 	frame->bh = NULL;
-	if (!(bh = ext4_bread(NULL, dir, 0, 0, err))) {
-		if (*err == 0)
-			*err = ERR_BAD_DX_DIR;
+	bh = ext4_read_dirblock(dir, 0, INDEX);
+	if (IS_ERR(bh)) {
+		*err = PTR_ERR(bh);
 		goto fail;
 	}
 	root = (struct dx_root *) bh->b_data;
@@ -643,15 +723,6 @@ dx_probe(const struct qstr *d_name, struct inode *dir,
 		goto fail;
 	}
 
-	if (!buffer_verified(bh) &&
-	    !ext4_dx_csum_verify(dir, (struct ext4_dir_entry *)bh->b_data)) {
-		ext4_warning(dir->i_sb, "Root failed checksum");
-		brelse(bh);
-		*err = ERR_BAD_DX_DIR;
-		goto fail;
-	}
-	set_buffer_verified(bh);
-
 	entries = (struct dx_entry *) (((char *)&root->info) +
 				       root->info.info_length);
 
@@ -709,23 +780,13 @@ dx_probe(const struct qstr *d_name, struct inode *dir,
 		frame->entries = entries;
 		frame->at = at;
 		if (!indirect--) return frame;
-		if (!(bh = ext4_bread(NULL, dir, dx_get_block(at), 0, err))) {
-			if (!(*err))
-				*err = ERR_BAD_DX_DIR;
+		bh = ext4_read_dirblock(dir, dx_get_block(at), INDEX);
+		if (IS_ERR(bh)) {
+			*err = PTR_ERR(bh);
 			goto fail2;
 		}
 		entries = ((struct dx_node *) bh->b_data)->entries;
 
-		if (!buffer_verified(bh) &&
-		    !ext4_dx_csum_verify(dir,
-					 (struct ext4_dir_entry *)bh->b_data)) {
-			ext4_warning(dir->i_sb, "Node failed checksum");
-			brelse(bh);
-			*err = ERR_BAD_DX_DIR;
-			goto fail2;
-		}
-		set_buffer_verified(bh);
-
 		if (dx_get_limit(entries) != dx_node_limit (dir)) {
 			ext4_warning(dir->i_sb,
 				     "dx entry: limit != node limit");
@@ -783,7 +844,7 @@ static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 {
 	struct dx_frame *p;
 	struct buffer_head *bh;
-	int err, num_frames = 0;
+	int num_frames = 0;
 	__u32 bhash;
 
 	p = frame;
@@ -822,26 +883,9 @@ static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 	 * block so no check is necessary
 	 */
 	while (num_frames--) {
-		if (!(bh = ext4_bread(NULL, dir, dx_get_block(p->at),
-				      0, &err))) {
-			if (!err) {
-				ext4_error(dir->i_sb,
-					   "Directory hole detected on inode %lu\n",
-					   dir->i_ino);
-				return -EIO;
-			}
-			return err; /* Failure */
-		}
-
-		if (!buffer_verified(bh) &&
-		    !ext4_dx_csum_verify(dir,
-					 (struct ext4_dir_entry *)bh->b_data)) {
-			ext4_warning(dir->i_sb, "Node failed checksum");
-			brelse(bh);
-			return -EIO;
-		}
-		set_buffer_verified(bh);
-
+		bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
+		if (IS_ERR(bh))
+			return PTR_ERR(bh);
 		p++;
 		brelse(p->bh);
 		p->bh = bh;
@@ -867,23 +911,9 @@ static int htree_dirblock_to_tree(struct file *dir_file,
 
 	dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
 							(unsigned long)block));
-	if (!(bh = ext4_bread(NULL, dir, block, 0, &err))) {
-		if (!err) {
-			err = -EIO;
-			ext4_error(dir->i_sb,
-				   "Directory hole detected on inode %lu\n",
-				   dir->i_ino);
-		}
-		return err;
-	}
-
-	if (!buffer_verified(bh) &&
-			!ext4_dirent_csum_verify(dir,
-				(struct ext4_dir_entry *)bh->b_data)) {
-		brelse(bh);
-		return -EIO;
-	}
-	set_buffer_verified(bh);
+	bh = ext4_read_dirblock(dir, block, DIRENT);
+	if (IS_ERR(bh))
+		return PTR_ERR(bh);
 
 	de = (struct ext4_dir_entry_2 *) bh->b_data;
 	top = (struct ext4_dir_entry_2 *) ((char *) de +
@@ -1337,26 +1367,11 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir, const struct q
 		return NULL;
 	do {
 		block = dx_get_block(frame->at);
-		if (!(bh = ext4_bread(NULL, dir, block, 0, err))) {
-			if (!(*err)) {
-				*err = -EIO;
-				ext4_error(dir->i_sb,
-					   "Directory hole detected on inode %lu\n",
-					   dir->i_ino);
-			}
+		bh = ext4_read_dirblock(dir, block, DIRENT);
+		if (IS_ERR(bh)) {
+			*err = PTR_ERR(bh);
 			goto errout;
 		}
-
-		if (!buffer_verified(bh) &&
-		    !ext4_dirent_csum_verify(dir,
-				(struct ext4_dir_entry *)bh->b_data)) {
-			EXT4_ERROR_INODE(dir, "checksumming directory "
-					 "block %lu", (unsigned long)block);
-			brelse(bh);
-			*err = -EIO;
-			goto errout;
-		}
-		set_buffer_verified(bh);
 		retval = search_dirblock(bh, dir, d_name,
 					 block << EXT4_BLOCK_SIZE_BITS(sb),
 					 res_dir);
@@ -1920,22 +1935,10 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
 	}
 	blocks = dir->i_size >> sb->s_blocksize_bits;
 	for (block = 0; block < blocks; block++) {
-		if (!(bh = ext4_bread(handle, dir, block, 0, &retval))) {
-			if (!retval) {
-				retval = -EIO;
-				ext4_error(inode->i_sb,
-					   "Directory hole detected on inode %lu\n",
-					   inode->i_ino);
-			}
-			return retval;
-		}
-		if (!buffer_verified(bh) &&
-		    !ext4_dirent_csum_verify(dir,
-				(struct ext4_dir_entry *)bh->b_data)) {
-			brelse(bh);
-			return -EIO;
-		}
-		set_buffer_verified(bh);
+		bh = ext4_read_dirblock(dir, block, DIRENT);
+		if (IS_ERR(bh))
+			return PTR_ERR(bh);
+
 		retval = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
 		if (retval != -ENOSPC) {
 			brelse(bh);
@@ -1986,22 +1989,13 @@ static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
 		return err;
 	entries = frame->entries;
 	at = frame->at;
-
-	if (!(bh = ext4_bread(handle, dir, dx_get_block(frame->at), 0, &err))) {
-		if (!err) {
-			err = -EIO;
-			ext4_error(dir->i_sb,
-				   "Directory hole detected on inode %lu\n",
-				   dir->i_ino);
-		}
+	bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT);
+	if (IS_ERR(bh)) {
+		err = PTR_ERR(bh);
+		bh = NULL;
 		goto cleanup;
 	}
 
-	if (!buffer_verified(bh) &&
-	    !ext4_dirent_csum_verify(dir, (struct ext4_dir_entry *)bh->b_data))
-		goto journal_error;
-	set_buffer_verified(bh);
-
 	BUFFER_TRACE(bh, "get_write_access");
 	err = ext4_journal_get_write_access(handle, bh);
 	if (err)
@@ -2352,6 +2346,7 @@ static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
 	struct buffer_head *dir_block = NULL;
 	struct ext4_dir_entry_2 *de;
 	struct ext4_dir_entry_tail *t;
+	ext4_lblk_t block = 0;
 	unsigned int blocksize = dir->i_sb->s_blocksize;
 	int csum_size = 0;
 	int err;
@@ -2368,16 +2363,9 @@ static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
 			goto out;
 	}
 
-	inode->i_size = EXT4_I(inode)->i_disksize = blocksize;
-	if (!(dir_block = ext4_bread(handle, inode, 0, 1, &err))) {
-		if (!err) {
-			err = -EIO;
-			ext4_error(inode->i_sb,
-				   "Directory hole detected on inode %lu\n",
-				   inode->i_ino);
-		}
+	inode->i_size = 0;
+	if (!(dir_block = ext4_append(handle, inode, &block, &err)))
 		goto out;
-	}
 	BUFFER_TRACE(dir_block, "get_write_access");
 	err = ext4_journal_get_write_access(handle, dir_block);
 	if (err)
@@ -2477,26 +2465,14 @@ static int empty_dir(struct inode *inode)
 	}
 
 	sb = inode->i_sb;
-	if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2) ||
-	    !(bh = ext4_bread(NULL, inode, 0, 0, &err))) {
-		if (err)
-			EXT4_ERROR_INODE(inode,
-				"error %d reading directory lblock 0", err);
-		else
-			ext4_warning(inode->i_sb,
-				     "bad directory (dir #%lu) - no data block",
-				     inode->i_ino);
+	if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
+		EXT4_ERROR_INODE(inode, "invalid size");
 		return 1;
 	}
-	if (!buffer_verified(bh) &&
-	    !ext4_dirent_csum_verify(inode,
-			(struct ext4_dir_entry *)bh->b_data)) {
-		EXT4_ERROR_INODE(inode, "checksum error reading directory "
-				 "lblock 0");
-		brelse(bh);
-		return -EIO;
-	}
-	set_buffer_verified(bh);
+	bh = ext4_read_dirblock(inode, 0, EITHER);
+	if (IS_ERR(bh))
+		return 1;
+
 	de = (struct ext4_dir_entry_2 *) bh->b_data;
 	de1 = ext4_next_entry(de, sb->s_blocksize);
 	if (le32_to_cpu(de->inode) != inode->i_ino ||
@@ -2519,29 +2495,9 @@ static int empty_dir(struct inode *inode)
 			err = 0;
 			brelse(bh);
 			lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
-			bh = ext4_bread(NULL, inode, lblock, 0, &err);
-			if (!bh) {
-				if (err)
-					EXT4_ERROR_INODE(inode,
-						"error %d reading directory "
-						"lblock %u", err, lblock);
-				else
-					ext4_warning(inode->i_sb,
-						"bad directory (dir #%lu) - no data block",
-						inode->i_ino);
-
-				offset += sb->s_blocksize;
-				continue;
-			}
-			if (!buffer_verified(bh) &&
-			    !ext4_dirent_csum_verify(inode,
-					(struct ext4_dir_entry *)bh->b_data)) {
-				EXT4_ERROR_INODE(inode, "checksum error "
-						 "reading directory lblock 0");
-				brelse(bh);
-				return -EIO;
-			}
-			set_buffer_verified(bh);
+			bh = ext4_read_dirblock(inode, lblock, EITHER);
+			if (IS_ERR(bh))
+				return 1;
 			de = (struct ext4_dir_entry_2 *) bh->b_data;
 		}
 		if (ext4_check_dir_entry(inode, NULL, de, bh,
@@ -3004,13 +2960,9 @@ static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
 	struct buffer_head *bh;
 
 	if (!ext4_has_inline_data(inode)) {
-		if (!(bh = ext4_bread(handle, inode, 0, 0, retval))) {
-			if (!*retval) {
-				*retval = -EIO;
-				ext4_error(inode->i_sb,
-					   "Directory hole detected on inode %lu\n",
-					   inode->i_ino);
-			}
+		bh = ext4_read_dirblock(inode, 0, EITHER);
+		if (IS_ERR(bh)) {
+			*retval = PTR_ERR(bh);
 			return NULL;
 		}
 		*parent_de = ext4_next_entry(
@@ -3089,11 +3041,6 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
 						  &inlined);
 		if (!dir_bh)
 			goto end_rename;
-		if (!inlined && !buffer_verified(dir_bh) &&
-		    !ext4_dirent_csum_verify(old_inode,
-				(struct ext4_dir_entry *)dir_bh->b_data))
-			goto end_rename;
-		set_buffer_verified(dir_bh);
 		if (le32_to_cpu(parent_de->inode) != old_dir->i_ino)
 			goto end_rename;
 		retval = -EMLINK;