linux-kernel - [PATCH 2/9] f2fs: avoid unneeded initializing when converting inline dentry

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 19 Aug 2015 19:10:19 +0800
From:	Chao Yu <chao2.yu@...sung.com>
To:	Jaegeuk Kim <jaegeuk@...nel.org>
Cc:	linux-f2fs-devel@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/9] f2fs: avoid unneeded initializing when converting inline
 dentry

When converting inline dentry, we will zero out target dentry page before
duplicating data of inline dentry into target page, it become overhead
since inline dentry size is not small.

So this patch tries to remove unneeded initializing in the space of target
dentry page.

Signed-off-by: Chao Yu <chao2.yu@...sung.com>
---
 fs/f2fs/inline.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index 79d18d5..e4da0d7 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -384,17 +384,30 @@ static int f2fs_convert_inline_dir(struct inode *dir, struct page *ipage,
 		goto out;
 
 	f2fs_wait_on_page_writeback(page, DATA);
-	zero_user_segment(page, 0, PAGE_CACHE_SIZE);
+	zero_user_segment(page, MAX_INLINE_DATA, PAGE_CACHE_SIZE);
 
 	dentry_blk = kmap_atomic(page);
 
 	/* copy data from inline dentry block to new dentry block */
 	memcpy(dentry_blk->dentry_bitmap, inline_dentry->dentry_bitmap,
 					INLINE_DENTRY_BITMAP_SIZE);
+	memset(dentry_blk->dentry_bitmap + INLINE_DENTRY_BITMAP_SIZE, 0,
+			SIZE_OF_DENTRY_BITMAP - INLINE_DENTRY_BITMAP_SIZE);
+	/*
+	 * reserved space size of inline dentry is larger than the one of
+	 * regular dentry, here we just copy with the size of reserved space
+	 * in regular dentry.
+	 */
+	memcpy(dentry_blk->reserved, inline_dentry->reserved, SIZE_OF_RESERVED);
 	memcpy(dentry_blk->dentry, inline_dentry->dentry,
 			sizeof(struct f2fs_dir_entry) * NR_INLINE_DENTRY);
+	memset(dentry_blk->dentry + NR_INLINE_DENTRY, 0,
+			sizeof (struct f2fs_dir_entry) *
+			(NR_DENTRY_IN_BLOCK - NR_INLINE_DENTRY));
 	memcpy(dentry_blk->filename, inline_dentry->filename,
 					NR_INLINE_DENTRY * F2FS_SLOT_LEN);
+	memset(&dentry_blk->filename[NR_INLINE_DENTRY][0], 0,
+		F2FS_SLOT_LEN * (NR_DENTRY_IN_BLOCK - NR_INLINE_DENTRY));
 
 	kunmap_atomic(dentry_blk);
 	SetPageUptodate(page);
-- 
2.4.2


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/