ext2, ext4: fix issue with missing journal entry in ext4_dax_mkwrite()
As it is currently written ext4_dax_mkwrite() assumes that the call into
__dax_mkwrite() will not have to do a block allocation so it doesn't create
a journal entry. For a read that creates a zero page to cover a hole
followed by a write that actually allocates storage this is incorrect. The
ext4_dax_mkwrite() -> __dax_mkwrite() -> __dax_fault() path calls
get_blocks() to allocate storage.
Fix this by having the ->page_mkwrite fault handler call ext4_dax_fault()
as this function already has all the logic needed to allocate a journal
entry and call __dax_fault().
Also update the ext2 fault handlers in this same way to remove duplicate
code and keep the logic between ext2 and ext4 the same.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 2c88d68..c1400b1 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -80,23 +80,6 @@
return ret;
}
-static int ext2_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
-{
- struct inode *inode = file_inode(vma->vm_file);
- struct ext2_inode_info *ei = EXT2_I(inode);
- int ret;
-
- sb_start_pagefault(inode->i_sb);
- file_update_time(vma->vm_file);
- down_read(&ei->dax_sem);
-
- ret = __dax_mkwrite(vma, vmf, ext2_get_block, NULL);
-
- up_read(&ei->dax_sem);
- sb_end_pagefault(inode->i_sb);
- return ret;
-}
-
static int ext2_dax_pfn_mkwrite(struct vm_area_struct *vma,
struct vm_fault *vmf)
{
@@ -124,7 +107,7 @@
static const struct vm_operations_struct ext2_dax_vm_ops = {
.fault = ext2_dax_fault,
.pmd_fault = ext2_dax_pmd_fault,
- .page_mkwrite = ext2_dax_mkwrite,
+ .page_mkwrite = ext2_dax_fault,
.pfn_mkwrite = ext2_dax_pfn_mkwrite,
};