The patch titled
ext4: use simple_prepare_write to zero page data
has been added to the -mm tree. Its filename is
ext4-use-simple_prepare_write-to-zero-page-data.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: ext4: use simple_prepare_write to zero page data
From: Nate Diller <nate.diller@xxxxxxxxx>
It's common for file systems to need to zero data on either side of a
write, if a page is not Uptodate during prepare_write. It just so happens
that simple_prepare_write() in libfs.c does exactly that, so we can avoid
duplication and just call that function to zero page data.
Signed-off-by: Nate Diller <nate.diller@xxxxxxxxx>
Cc: <linux-ext4@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/reiser4/plugin/item/extent_file_ops.c | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)
diff -puN fs/reiser4/plugin/item/extent_file_ops.c~ext4-use-simple_prepare_write-to-zero-page-data fs/reiser4/plugin/item/extent_file_ops.c
--- a/fs/reiser4/plugin/item/extent_file_ops.c~ext4-use-simple_prepare_write-to-zero-page-data
+++ a/fs/reiser4/plugin/item/extent_file_ops.c
@@ -1040,16 +1040,9 @@ ssize_t reiser4_write_extent(struct file
BUG_ON(get_current_context()->trans->atom != NULL);
lock_page(page);
- if (!PageUptodate(page) && to_page != PAGE_CACHE_SIZE) {
- void *kaddr;
-
- kaddr = kmap_atomic(page, KM_USER0);
- memset(kaddr, 0, page_off);
- memset(kaddr + page_off + to_page, 0,
- PAGE_CACHE_SIZE - (page_off + to_page));
- flush_dcache_page(page);
- kunmap_atomic(kaddr, KM_USER0);
- }
+ if (!PageUptodate(page) && to_page != PAGE_CACHE_SIZE)
+ simple_prepare_write(file, page, page_off,
+ page_off + to_page);
written = filemap_copy_from_user(page, page_off, buf, to_page);
flush_dcache_page(page);
_
Patches currently in -mm which might be from nate.diller@xxxxxxxxx are
cifs-use-simple_prepare_write-to-zero-page-data.patch
reiser4-use-simple_prepare_write-to-zero-page-data.patch
ext4-use-simple_prepare_write-to-zero-page-data.patch
-
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