Re: [f2fs-dev] [PATCH 1/3] f2fs: call flush_dcache_page when the page was updated

[Jaegeuk Kim]

On Thu, Nov 20, 2014 at 03:04:10PM +0900, Changman Lee wrote:
> Hi Jaegeuk,
> 
> We should call flush_dcache_page before kunmap because the purpose of the 
> cache flush is to address aliasing problem related to virtual address.

Oh, I just followed zero_user_segments below.

static inline void zero_user_segments(struct page *page,
        unsigned start1, unsigned end1,
        unsigned start2, unsigned end2)
{
        void *kaddr = kmap_atomic(page);

        BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);

        if (end1 > start1)
                memset(kaddr + start1, 0, end1 - start1);

        if (end2 > start2)
                memset(kaddr + start2, 0, end2 - start2);

        kunmap_atomic(kaddr);
        flush_dcache_page(page);
}

Is this a wrong reference? Or, a bug?

Anyway I modified as below.

Thanks,

>From 7cb7b27c8cd2efc8a31d79239bef5b41c6e79216 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaeg...@kernel.org>
Date: Tue, 18 Nov 2014 10:50:21 -0800
Subject: [PATCH] f2fs: call flush_dcache_page when the page was updated

Whenever f2fs updates mapped pages, it needs to call flush_dcache_page.

Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
---
 fs/f2fs/dir.c    | 7 ++++++-
 fs/f2fs/inline.c | 2 ++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 5a49995..fabf4ee 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -287,8 +287,10 @@ void f2fs_set_link(struct inode *dir, struct 
f2fs_dir_entry *de,
        f2fs_wait_on_page_writeback(page, type);
        de->ino = cpu_to_le32(inode->i_ino);
        set_de_type(de, inode);
-       if (!f2fs_has_inline_dentry(dir))
+       if (!f2fs_has_inline_dentry(dir)) {
+               flush_dcache_page(page);
                kunmap(page);
+       }
        set_page_dirty(page);
        dir->i_mtime = dir->i_ctime = CURRENT_TIME;
        mark_inode_dirty(dir);
@@ -365,6 +367,7 @@ static int make_empty_dir(struct inode *inode,
        make_dentry_ptr(&d, (void *)dentry_blk, 1);
        do_make_empty_dir(inode, parent, &d);
 
+       flush_dcache_page(dentry_page);
        kunmap_atomic(dentry_blk);
 
        set_page_dirty(dentry_page);
@@ -578,6 +581,7 @@ fail:
                update_inode_page(dir);
                clear_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
        }
+       flush_dcache_page(dentry_page);
        kunmap(dentry_page);
        f2fs_put_page(dentry_page, 1);
        return err;
@@ -660,6 +664,7 @@ void f2fs_delete_entry(struct f2fs_dir_entry *dentry, 
struct page *page,
        bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
                        NR_DENTRY_IN_BLOCK,
                        0);
+       flush_dcache_page(page);
        kunmap(page); /* kunmap - pair of f2fs_find_entry */
        set_page_dirty(page);
 
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index f26fb87..4291c1f 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -106,6 +106,7 @@ int f2fs_convert_inline_page(struct dnode_of_data *dn, 
struct page *page)
        src_addr = inline_data_addr(dn->inode_page);
        dst_addr = kmap_atomic(page);
        memcpy(dst_addr, src_addr, MAX_INLINE_DATA);
+       flush_dcache_page(page);
        kunmap_atomic(dst_addr);
        SetPageUptodate(page);
 no_update:
@@ -357,6 +358,7 @@ static int f2fs_convert_inline_dir(struct inode *dir, 
struct page *ipage,
        memcpy(dentry_blk->filename, inline_dentry->filename,
                                        NR_INLINE_DENTRY * F2FS_SLOT_LEN);
 
+       flush_dcache_page(page);
        kunmap_atomic(dentry_blk);
        SetPageUptodate(page);
        set_page_dirty(page);
-- 
2.1.1


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