Hi Andrew I finally had the time to beat up these fixes based on linux-next/akpm and it looks OK. I'm sending the two fix patches with @stable + a patch-1 for the 4.0 Kernel. The 4.1-rc Kernel will need a different patch. It is your call if you want these in stable. It is a breakage in the dax code that went into 4.0. But I guess it will not have that many users right at the get go. So feel free to remove the CC:@stable. (Also the old XIP that this DAX changed had all the same problems) [v5] * A new patch-1 Based on linux-next/akpm branch because mm/memory.c completely changed there. Also a 4.0 version of the same patch-1 if needed for stable@ List of patches: [PATCH 1/3] mm(v4.1): New pfn_mkwrite same as page_mkwrite for VM_PFNMAP [PATCH 2/3] dax: use pfn_mkwrite to update c/mtime + freeze [PATCH 3/3] dax: Unify ext2/4_{dax,}_file_operations All these patches are based on linux-next/akpm. I'm not sure how it will interact with ext4-next though. [PATCH 1/3 @stable] mm(v4.0): New pfn_mkwrite same as page_mkwrite for VM_PFNMAP This patch is for 4.0 based tree if we decide to send [PATCH 2/3] to stable. [v4] dax: some dax fixes and cleanups * First patch fixed according to Andrew's comments. Thanks Andrew. 1st and 2nd patch can go into current Kernel as they fix something that was merged this release. * Added a new patch to fix up splice in the dax case, and cleanup. This one can wait for 4.1 (Also the first two not that anyone uses dax in production.) * DAX freeze is not fixed yet. As we have more problems then I originally hoped for, as pointed out by Dave. (Just as a referance I'm sending a NO-GOOD additional patch to show what is not good enough to do. Was the RFC of [v3]) * Not re-posting the xfstest Dave please pick this up (It already found bugs in none dax FSs) [v3] dax: Fix mmap-write not updating c/mtime * I'm re-posting the two DAX patches that fix the mmap-write after read problem with DAX. (No changes since [v2]) * I'm also posting a 3rd RFC patch to address what Jan said about fs_freeze and making mapping read-only. Jan Please review and see if this is what you meant. [v2] Jan Kara has pointed out that if we add the sb_start/end_pagefault pair in the new pfn_mkwrite we are then fixing another bug where: A user could start writing to the page while filesystem is frozen. [v1] The main problem is that current mm/memory.c will no call us with page_mkwrite if we do not have an actual page mapping, which is what DAX uses. The solution presented here introduces a new pfn_mkwrite to solve this problem. Please see patch-2 for details. I've been running with this patch for 4 month both HW and VMs with no apparent danger, but see patch-1 I played it safe. I am also posting an xfstest 080 that demonstrate this problem, I believe that also some git operations (can't remember which) suffer from this problem. Actually Eryu Guan found that this test fails on some other FS as well. Matthew hi I would love to have your ACK on these patches? Thanks Boaz -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html