Code: ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
{
 	struct inode *inode = d_inode(dentry);
 	struct buffer_head *bh = NULL;
 	int error;
	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 
 	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 		  buffer, (long)buffer_size);

	error = 0;
	if (!EXT4_I(inode)->i_file_acl)
		goto cleanup;
	ea_idebug(inode, "reading block %llu",
		  (unsigned long long)EXT4_I(inode)->i_file_acl);
	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
	error = -EIO;
	if (!bh)
		goto cleanup;
	ea_bdebug(bh, "b_count=%d, refcount=%d",
		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
	if (ext4_xattr_check_block(inode, bh)) {
		EXT4_ERROR_INODE(inode, "bad block %llu",
				 EXT4_I(inode)->i_file_acl);
		error = -EFSCORRUPTED;
		goto cleanup;
	}
	ext4_xattr_cache_insert(ext4_mb_cache, bh);
	error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);

cleanup:
	brelse(bh);

	return error;
}

Commit Message: ext4: convert to mbcache2

The conversion is generally straightforward. The only tricky part is
that xattr block corresponding to found mbcache entry can get freed
before we get buffer lock for that block. So we have to check whether
the entry is still valid after getting buffer lock.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
CWE ID: CWE-19
ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
{
 	struct inode *inode = d_inode(dentry);
 	struct buffer_head *bh = NULL;
 	int error;
	struct mb2_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 
 	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
 		  buffer, (long)buffer_size);

	error = 0;
	if (!EXT4_I(inode)->i_file_acl)
		goto cleanup;
	ea_idebug(inode, "reading block %llu",
		  (unsigned long long)EXT4_I(inode)->i_file_acl);
	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
	error = -EIO;
	if (!bh)
		goto cleanup;
	ea_bdebug(bh, "b_count=%d, refcount=%d",
		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
	if (ext4_xattr_check_block(inode, bh)) {
		EXT4_ERROR_INODE(inode, "bad block %llu",
				 EXT4_I(inode)->i_file_acl);
		error = -EFSCORRUPTED;
		goto cleanup;
	}
	ext4_xattr_cache_insert(ext4_mb_cache, bh);
	error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);

cleanup:
	brelse(bh);

	return error;
}
