[PATCH 07/27] mm: Update file times from fault path only if .page_mkwrite is not set

From: Jan Kara
Date: Tue Jun 12 2012 - 10:28:42 EST


Filesystems wanting to properly support freezing need to have control
when file_update_time() is called. After pushing file_update_time()
to all relevant .page_mkwrite implementations we can just stop calling
file_update_time() when filesystem implements .page_mkwrite.

Tested-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
Tested-by: Peter M. Petrakis <peter.petrakis@xxxxxxxxxxxxx>
Tested-by: Dann Frazier <dann.frazier@xxxxxxxxxxxxx>
Tested-by: Massimo Morana <massimo.morana@xxxxxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
mm/memory.c | 14 +++++++-------
1 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 1b7dc66..26f0283 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2630,6 +2630,9 @@ reuse:
if (!page_mkwrite) {
wait_on_page_locked(dirty_page);
set_page_dirty_balance(dirty_page, page_mkwrite);
+ /* file_update_time outside page_lock */
+ if (vma->vm_file)
+ file_update_time(vma->vm_file);
}
put_page(dirty_page);
if (page_mkwrite) {
@@ -2647,10 +2650,6 @@ reuse:
}
}

- /* file_update_time outside page_lock */
- if (vma->vm_file)
- file_update_time(vma->vm_file);
-
return ret;
}

@@ -3319,12 +3318,13 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,

if (dirty_page) {
struct address_space *mapping = page->mapping;
+ int dirtied = 0;

if (set_page_dirty(dirty_page))
- page_mkwrite = 1;
+ dirtied = 1;
unlock_page(dirty_page);
put_page(dirty_page);
- if (page_mkwrite && mapping) {
+ if ((dirtied || page_mkwrite) && mapping) {
/*
* Some device drivers do not set page.mapping but still
* dirty their pages
@@ -3333,7 +3333,7 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
}

/* file_update_time outside page_lock */
- if (vma->vm_file)
+ if (vma->vm_file && !page_mkwrite)
file_update_time(vma->vm_file);
} else {
unlock_page(vmf.page);
--
1.7.1

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