Re: [f2fs-dev] [PATCH 4/4] f2fs: avoid wrong f2fs_bug_on when truncating inline_data

From: Jaegeuk Kim
Date: Wed Mar 18 2015 - 13:57:59 EST


Hi,

On Wed, Mar 18, 2015 at 09:12:00AM +0800, Chao Yu wrote:
> Hi Jaegeuk,
>
> > -----Original Message-----
> > From: Jaegeuk Kim [mailto:jaegeuk@xxxxxxxxxx]
> > Sent: Wednesday, March 18, 2015 12:58 AM
> > To: linux-kernel@xxxxxxxxxxxxxxx; linux-fsdevel@xxxxxxxxxxxxxxx;
> > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx
> > Cc: Jaegeuk Kim
> > Subject: [f2fs-dev] [PATCH 4/4] f2fs: avoid wrong f2fs_bug_on when truncating inline_data
> >
> > This patch removes wrong f2fs_bug_on in truncate_inline_inode.
> >
> > When there is no space, it can happen a corner case where i_isze is over
> > MAX_INLINE_SIZE while its inode is still inline_data.
> >
> > The scenario is
> > 1. write small data into file #A.
> > 2. fill the whole partition to 100%.
> > 3. truncate 4096 on file #A.
>
> If we truncate size over MAX_INLINE_DATA, we will convert inline data in
> f2fs_truncate rather than write_begin below. isn't it?

But, it fails to convert that due to -ENOSPC. :)

Thanks,

>
> Thanks,
>
> > 4. write data at 8192 offset.
> > --> f2fs_write_begin
> > -> -ENOSPC = f2fs_convert_inline_page
> > -> f2fs_write_failed
> > -> truncate_blocks
> > -> truncate_inline_inode
> > BUG_ON, since i_size is 4096.
> >
> > Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> > ---
> > fs/f2fs/inline.c | 7 -------
> > 1 file changed, 7 deletions(-)
> >
> > diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
> > index 153c5e7..d3e0599 100644
> > --- a/fs/f2fs/inline.c
> > +++ b/fs/f2fs/inline.c
> > @@ -54,13 +54,6 @@ bool truncate_inline_inode(struct page *ipage, u64 from)
> > {
> > void *addr;
> >
> > - /*
> > - * 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(F2FS_P_SB(ipage), from > MAX_INLINE_DATA);
> > -
> > if (from >= MAX_INLINE_DATA)
> > return false;
> >
> > --
> > 2.1.1
> >
> >
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