Re: [f2fs-dev] [PATCH v2] f2fs: change the way of handling range.len in F2FS_IOC_SEC_TRIM_FILE

[Daeho Jeong]

We could use fscrypt_zeroout_range() for an encrypted file.
But, one problem is fscrypt_zeroout_range() assumes that filesystems
only use a single block device.
It means it doesn't receive bdev as a parameter.
How about changing the interface of fscrypt_zeroout_range() first and using it?

2020ë 7ì 14ì (í) ìí 9:36, Chao Yu <yuchao0@xxxxxxxxxx>ëì ìì:
>
> On 2020/7/14 2:11, Jaegeuk Kim wrote:
> > Hi Daeho,
> >
> > Please take a look at this.
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git/commit/?h=dev&id=35245180459aebf6d70fde88a538f0400a794aa6
>
> I'm curious about what will happen if we call
> sec_trim_file(F2FS_TRIM_FILE_ZEROOUT) on an encrypted file, will
> it use zero bits covering encrypted data on disk?
>
> Thanks,
>
> >
> > Thanks,
> >
> > On 07/13, Daeho Jeong wrote:
> >> From: Daeho Jeong <daehojeong@xxxxxxxxxx>
> >>
> >> Changed the way of handling range.len of F2FS_IOC_SEC_TRIM_FILE.
> >>  1. Added -1 value support for range.len to secure trim the whole blocks
> >>     starting from range.start regardless of i_size.
> >>  2. If the end of the range passes over the end of file, it means until
> >>     the end of file (i_size).
> >>  3. ignored the case of that range.len is zero to prevent the function
> >>     from making end_addr zero and triggering different behaviour of
> >>     the function.
> >>
> >> Signed-off-by: Daeho Jeong <daehojeong@xxxxxxxxxx>
> >> ---
> >> Changes in v2:
> >>  - Changed -1 range.len option to mean the whole blocks starting from
> >>    range.start regardless of i_size
> >> ---
> >>  fs/f2fs/file.c | 23 ++++++++++++-----------
> >>  1 file changed, 12 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> >> index 368c80f8e2a1..2485841e3b2d 100644
> >> --- a/fs/f2fs/file.c
> >> +++ b/fs/f2fs/file.c
> >> @@ -3792,7 +3792,7 @@ static int f2fs_sec_trim_file(struct file *filp, unsigned long arg)
> >>      pgoff_t index, pg_end;
> >>      block_t prev_block = 0, len = 0;
> >>      loff_t end_addr;
> >> -    bool to_end;
> >> +    bool to_end = false;
> >>      int ret = 0;
> >>
> >>      if (!(filp->f_mode & FMODE_WRITE))
> >> @@ -3813,23 +3813,23 @@ 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;
> >> -            goto err;
> >> +    if (inode->i_size - range.start > range.len) {
> >> +            end_addr = range.start + range.len;
> >> +    } else {
> >> +            end_addr = range.len == (u64)-1 ?
> >> +                    sbi->sb->s_maxbytes : inode->i_size;
> >> +            to_end = true;
> >>      }
> >> -    end_addr = range.start + range.len;
> >>
> >> -    to_end = (end_addr == inode->i_size);
> >>      if (!IS_ALIGNED(range.start, F2FS_BLKSIZE) ||
> >>                      (!to_end && !IS_ALIGNED(end_addr, F2FS_BLKSIZE))) {
> >>              ret = -EINVAL;
> >> @@ -3846,7 +3846,8 @@ static int f2fs_sec_trim_file(struct file *filp, unsigned long arg)
> >>      down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
> >>      down_write(&F2FS_I(inode)->i_mmap_sem);
> >>
> >> -    ret = filemap_write_and_wait_range(mapping, range.start, end_addr - 1);
> >> +    ret = filemap_write_and_wait_range(mapping, range.start,
> >> +                    to_end ? LLONG_MAX : end_addr - 1);
> >>      if (ret)
> >>              goto out;
> >>
> >> --
> >> 2.27.0.383.g050319c2ae-goog
> >
> >
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> > .
> >