Re: [f2fs-dev] [PATCH] f2fs: ignore when len of range in f2fs_sec_trim_file is zero

[Jaegeuk Kim]

On 07/09, Chao Yu wrote:
> On 2020/7/9 9:57, Daeho Jeong wrote:
> > From: Daeho Jeong <daehojeong@xxxxxxxxxx>
> > 
> > When end_addr comes to zero, it'll trigger different behaviour.
> > To prevent this, we need to ignore the case of that range.len is
> > zero in the function.
> > 
> > Signed-off-by: Daeho Jeong <daehojeong@xxxxxxxxxx>
> > ---
> >  fs/f2fs/file.c | 7 +++----
> >  1 file changed, 3 insertions(+), 4 deletions(-)
> > 
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index 368c80f8e2a1..98b0a8dbf669 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -3813,15 +3813,14 @@ static int f2fs_sec_trim_file(struct file *filp, unsigned long arg)
> >  	file_start_write(filp);
> >  	inode_lock(inode);
> >  
> > -	if (f2fs_is_atomic_file(inode) || f2fs_compressed_file(inode)) {
> > +	if (f2fs_is_atomic_file(inode) || f2fs_compressed_file(inode) ||
> > +			range.start >= inode->i_size) {
> >  		ret = -EINVAL;
> >  		goto err;
> >  	}
> >  
> > -	if (range.start >= inode->i_size) {
> > -		ret = -EINVAL;
> > +	if (range.len == 0)
> >  		goto err;
> > -	}
> >  
> >  	if (inode->i_size - range.start < range.len) {
> >  		ret = -E2BIG;
> 
> How about the case trimming last partial written block?
> 
> i_size = 8000
> range.start = 4096
> range.len = 4096
> 
> Do we need to roundup(isize, PAGE_SIZE) before comparison?

If we want to trim whole file, do we need to give the exact i_size?
Wouldn't it be better to give trim(0, -1)?

> 
> Thanks,
> 
> > 
> 
> 
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