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SubjectRe: [PATCH] f2fs: fix to truncate inline data past EOF
Hi Chao,


On Mon, Mar 09, 2015 at 10:24:35AM +0800, Chao Yu wrote:
> Hi Jaegeuk,
>
> > -----Original Message-----
> > From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> > Sent: Friday, March 06, 2015 5:34 AM
> > To: Chao Yu
> > Cc: Changman Lee; linux-f2fs-devel@lists.sourceforge.net; linux-kernel@vger.kernel.org
> > Subject: Re: [PATCH] f2fs: fix to truncate inline data past EOF
> >
> > Hi Chao,
> >
> > On Thu, Mar 05, 2015 at 05:41:32PM +0800, Chao Yu wrote:
> > > Previously if inode is with inline data, we will try to invalid partial inline
> > > data in page #0 when we truncate size of inode in truncate_partial_data_page().
> > > And then we set page #0 to dirty, after this we can synchronize inode page with
> > > page #0 at ->writepage().
> > >
> > > But sometimes we will fail to operate page #0 in truncate_partial_data_page()
> > > due to below reason:
> > > a) if offset is zero, we will skip setting page #0 to dirty.
> > > b) if page #0 is not uptodate, we will fail to update it as it has no mapping
> > > data.
> > >
> > > So with following operations, we will meet recent data which should be
> > > truncated.
> > >
> > > 1.write inline data to file
> > > 2.sync first data page to inode page
> > > 3.truncate file size to 0
> > > 4.truncate file size to max_inline_size
> > > 5.echo 1 > /proc/sys/vm/drop_caches
> > > 6.read file --> meet original inline data which is remained in inode page.
> > >
> > > This patch renames truncate_inline_data() to truncate_inline_inode() for code
> > > readability, then intruduces new truncate_inline_data() and use it to truncate
> > > inline data in page #0 and inode page in truncate_partial_data_page() for
> > > fixing.
> > >
> > > Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> > > ---
> > > fs/f2fs/f2fs.h | 1 +
> > > fs/f2fs/file.c | 13 ++++++++-----
> > > fs/f2fs/inline.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++-----
> > > 3 files changed, 61 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > > index 511d6cd..55dbbe7 100644
> > > --- a/fs/f2fs/f2fs.h
> > > +++ b/fs/f2fs/f2fs.h
> > > @@ -1754,6 +1754,7 @@ extern struct kmem_cache *inode_entry_slab;
> > > */
> > > bool f2fs_may_inline(struct inode *);
> > > void read_inline_data(struct page *, struct page *);
> > > +int truncate_inline_data(struct inode *, u64 from);
> > > int f2fs_read_inline_data(struct inode *, struct page *);
> > > int f2fs_convert_inline_page(struct dnode_of_data *, struct page *);
> > > int f2fs_convert_inline_inode(struct inode *);
> > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > > index f1341c7..6c4443e 100644
> > > --- a/fs/f2fs/file.c
> > > +++ b/fs/f2fs/file.c
> > > @@ -461,6 +461,9 @@ static int truncate_partial_data_page(struct inode *inode, u64 from)
> > > unsigned offset = from & (PAGE_CACHE_SIZE - 1);
> > > struct page *page;
> > >
> > > + if (f2fs_has_inline_data(inode))
> > > + return 0;
> > > +
> > > if (!offset)
> > > return 0;
> > >
> > > @@ -497,14 +500,14 @@ int truncate_blocks(struct inode *inode, u64 from, bool lock)
> > > if (lock)
> > > f2fs_lock_op(sbi);
> > >
> > > - ipage = get_node_page(sbi, inode->i_ino);
> > > - if (IS_ERR(ipage)) {
> > > - err = PTR_ERR(ipage);
> > > + if (f2fs_has_inline_data(inode)) {
> > > + err = truncate_inline_data(inode, from);
> > > goto out;
> > > }
> > >
> > > - if (f2fs_has_inline_data(inode)) {
> > > - f2fs_put_page(ipage, 1);
> > > + ipage = get_node_page(sbi, inode->i_ino);
> > > + if (IS_ERR(ipage)) {
> > > + err = PTR_ERR(ipage);
> > > goto out;
> > > }
> > >
> > > diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
> > > index 4ba9732..a8189c92 100644
> > > --- a/fs/f2fs/inline.c
> > > +++ b/fs/f2fs/inline.c
> > > @@ -50,10 +50,57 @@ void read_inline_data(struct page *page, struct page *ipage)
> > > SetPageUptodate(page);
> > > }
> > >
> > > -static void truncate_inline_data(struct page *ipage)
> > > +static void truncate_inline_inode(struct page *ipage, u64 from)
> > > {
> > > + void *addr = inline_data_addr(ipage);
> > > +
> > > f2fs_wait_on_page_writeback(ipage, NODE);
> > > - memset(inline_data_addr(ipage), 0, MAX_INLINE_DATA);
> > > + memset(addr + from, 0, MAX_INLINE_DATA - from);
> > > +}
> > > +
> > > +int truncate_inline_data(struct inode *inode, u64 from)
> > > +{
> > > + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> > > + struct page *page, *ipage;
> > > + void *addr;
> > > + int err = 0;
> > > +
> > > + /*
> > > + * we should never truncate inline data past max inline data size,
> > > + * because we always convert inline inode to normal one before
> > > + * truncating real data if new size is past max inline data size.
> > > + */
> > > + f2fs_bug_on(sbi, from > MAX_INLINE_DATA);
> > > +
> > > + if (from == MAX_INLINE_DATA)
> > > + return 0;
> > > +
> > > + page = grab_cache_page(inode->i_mapping, 0);
> > > + if (!page)
> > > + return -ENOMEM;
> >
> > Do we need to grab and read #0 page?
>
> No need to read #0 page, sorry for the mistake.
>
> > How about checking its cached page after on-disk truncation?
> >
> > 1. page = get_node_page()
> > 2. check_inline
> > 3. truncate_inline_inode
> > 4. f2fs_put_page(ipage)
> >
> > 5. truncate_partial_data_page(inode, from, force)
> > if (!offset && !force)
> > return 0;
> >
> > > +
> > > + ipage = get_node_page(sbi, inode->i_ino);
> > > + if (IS_ERR(ipage)) {
> > > + err = PTR_ERR(ipage);
> > > + goto out;
> > > + }
> > > +
> > > + if (!f2fs_has_inline_data(inode)) {
> > > + f2fs_put_page(ipage, 1);
> > > + goto out;
> > > + }
> > > +
> > > + truncate_inline_inode(ipage, from);
> > > + set_page_dirty(ipage);
> > > +
> > > + read_inline_data(page, ipage);
> > > + f2fs_put_page(ipage, 1);
> > > +
> > > + addr = inline_data_addr(page);
> > > + memset(addr + from, 0, MAX_INLINE_DATA - from);
> >
> > It needs to do likewise truncate_partial_data_page.
>
> Do you mean like this?

I meant this.

Anyway, I also wrote a patch about your testing scenario wrt inline_data.
So, let me submit the patch sooner or later to xfstests mailing list.

Thanks,

---
fs/f2fs/f2fs.h | 1 +
fs/f2fs/file.c | 10 +++++++---
fs/f2fs/inline.c | 12 +++++++-----
3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 31b440e..b222b3a 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1760,6 +1760,7 @@ extern struct kmem_cache *inode_entry_slab;
*/
bool f2fs_may_inline(struct inode *);
void read_inline_data(struct page *, struct page *);
+void truncate_inline_inode(struct page *, u64);
int f2fs_read_inline_data(struct inode *, struct page *);
int f2fs_convert_inline_page(struct dnode_of_data *, struct page *);
int f2fs_convert_inline_inode(struct inode *);
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index f1341c7..ab249dd 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -456,12 +456,12 @@ void truncate_data_blocks(struct dnode_of_data *dn)
truncate_data_blocks_range(dn, ADDRS_PER_BLOCK);
}

-static int truncate_partial_data_page(struct inode *inode, u64 from)
+static int truncate_partial_data_page(struct inode *inode, u64 from, bool force)
{
unsigned offset = from & (PAGE_CACHE_SIZE - 1);
struct page *page;

- if (!offset)
+ if (!offset && !force)
return 0;

page = find_data_page(inode, from >> PAGE_CACHE_SHIFT, false);
@@ -489,6 +489,7 @@ int truncate_blocks(struct inode *inode, u64 from, bool lock)
pgoff_t free_from;
int count = 0, err = 0;
struct page *ipage;
+ bool truncate_page = false;

trace_f2fs_truncate_blocks_enter(inode, from);

@@ -504,6 +505,9 @@ int truncate_blocks(struct inode *inode, u64 from, bool lock)
}

if (f2fs_has_inline_data(inode)) {
+ truncate_inline_inode(ipage, from);
+ set_page_dirty(ipage);
+ truncate_page = true;
f2fs_put_page(ipage, 1);
goto out;
}
@@ -535,7 +539,7 @@ out:

/* lastly zero out the first data page */
if (!err)
- err = truncate_partial_data_page(inode, from);
+ err = truncate_partial_data_page(inode, from, truncate_page);

trace_f2fs_truncate_blocks_exit(inode, err);
return err;
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index ee0984c..b236e30 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -50,10 +50,12 @@ void read_inline_data(struct page *page, struct page *ipage)
SetPageUptodate(page);
}

-static void truncate_inline_data(struct page *ipage)
+void truncate_inline_inode(struct page *ipage, u64 from)
{
+ void *addr = inline_data_addr(ipage);
+
f2fs_wait_on_page_writeback(ipage, NODE);
- memset(inline_data_addr(ipage), 0, MAX_INLINE_DATA);
+ memset(addr + from, 0, MAX_INLINE_DATA - from);
}

int f2fs_read_inline_data(struct inode *inode, struct page *page)
@@ -131,7 +133,7 @@ no_update:
set_inode_flag(F2FS_I(dn->inode), FI_APPEND_WRITE);

/* clear inline data and flag after data writeback */
- truncate_inline_data(dn->inode_page);
+ truncate_inline_inode(dn->inode_page, 0);
clear_out:
stat_dec_inline_inode(dn->inode);
f2fs_clear_inline_inode(dn->inode);
@@ -245,7 +247,7 @@ process_inline:
if (f2fs_has_inline_data(inode)) {
ipage = get_node_page(sbi, inode->i_ino);
f2fs_bug_on(sbi, IS_ERR(ipage));
- truncate_inline_data(ipage);
+ truncate_inline_inode(ipage, 0);
f2fs_clear_inline_inode(inode);
update_inode(inode, ipage);
f2fs_put_page(ipage, 1);
@@ -363,7 +365,7 @@ static int f2fs_convert_inline_dir(struct inode *dir, struct page *ipage,
set_page_dirty(page);

/* clear inline dir and flag after data writeback */
- truncate_inline_data(ipage);
+ truncate_inline_inode(ipage, 0);

stat_dec_inline_dir(dir);
clear_inode_flag(F2FS_I(dir), FI_INLINE_DENTRY);
--
2.1.1


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