On Thu, Jan 28, 2016 at 12:35:04PM -0700, Ross Zwisler wrote:
There are a number of places in dax.c that look up the struct
associated with an inode. Previously this was done by just using
inode->i_sb->s_bdev. This is correct for inodes that exist within the
filesystems supported by DAX (ext2, ext4 & XFS), but when running DAX
against raw block devices this value is NULL. This causes NULL pointer
dereferences when these block_device pointers are used.
It's also wrong for an XFS file system with a RT device..
+#define DAX_BDEV(inode) (S_ISBLK(inode->i_mode) ? I_BDEV(inode)
+ : inode->i_sb->s_bdev)
.. but this isn't going to fix it. You must use a bdev returned by
get_blocks or a similar file system method.