block: fix pfn_mkwrite() DAX fault handler

Previously the pfn_mkwrite() fault handler for raw block devices called
bldev_dax_fault() -> __dax_fault() to do a full DAX page fault.

Really what the pfn_mkwrite() fault handler needs to do is call
dax_pfn_mkwrite() to make sure that the radix tree entry for the given
PTE is marked as dirty so that a follow-up fsync or msync call will
flush it durably to media.

Fixes: 5a023cdba50c ("block: enable dax for raw block devices")
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/block_dev.c b/fs/block_dev.c
index afb4374..39b3a17 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1730,6 +1730,12 @@ static int blkdev_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
        return __dax_fault(vma, vmf, blkdev_get_block, NULL);
 }
 
+static int blkdev_dax_pfn_mkwrite(struct vm_area_struct *vma,
+               struct vm_fault *vmf)
+{
+       return dax_pfn_mkwrite(vma, vmf);
+}
+
 static int blkdev_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
                pmd_t *pmd, unsigned int flags)
 {
@@ -1739,7 +1745,7 @@ static int blkdev_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
 static const struct vm_operations_struct blkdev_dax_vm_ops = {
        .fault          = blkdev_dax_fault,
        .pmd_fault      = blkdev_dax_pmd_fault,
-       .pfn_mkwrite    = blkdev_dax_fault,
+       .pfn_mkwrite    = blkdev_dax_pfn_mkwrite,
 };
 
 static const struct vm_operations_struct blkdev_default_vm_ops = {