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SubjectRe: [f2fs-dev] [PATCH] f2fs: change the way of handling range.len in F2FS_IOC_SEC_TRIM_FILE
On 07/10, Chao Yu wrote:
> On 2020/7/10 11:52, Jaegeuk Kim wrote:
> > On 07/10, Chao Yu wrote:
> >> On 2020/7/10 11:31, Jaegeuk Kim wrote:
> >>> On 07/10, Chao Yu wrote:
> >>>> On 2020/7/10 11:02, Jaegeuk Kim wrote:
> >>>>> On 07/10, Daeho Jeong wrote:
> >>>>>> From: Daeho Jeong <daehojeong@google.com>
> >>>>>>
> >>>>>> Changed the way of handling range.len of F2FS_IOC_SEC_TRIM_FILE.
> >>>>>> 1. Added -1 value support for range.len to signify the end of file.
> >>>>>> 2. If the end of the range passes over the end of file, it means until
> >>>>>> the end of file.
> >>>>>> 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@google.com>
> >>>>>> ---
> >>>>>> fs/f2fs/file.c | 16 +++++++---------
> >>>>>> 1 file changed, 7 insertions(+), 9 deletions(-)
> >>>>>>
> >>>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> >>>>>> index 368c80f8e2a1..1c4601f99326 100644
> >>>>>> --- a/fs/f2fs/file.c
> >>>>>> +++ b/fs/f2fs/file.c
> >>>>>> @@ -3813,21 +3813,19 @@ 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;
> >>>>>> - }
> >>>>>> - end_addr = range.start + range.len;
> >>>>>> + if (range.len == (u64)-1 || inode->i_size - range.start < range.len)
> >>>>>> + end_addr = inode->i_size;
> >>>>
> >>>> We can remove 'range.len == (u64)-1' condition since later condition can cover
> >>>> this?
> >>>>
> >>>>>
> >>>>> Hmm, what if there are blocks beyond i_size? Do we need to check i_blocks for
> >>>>
> >>>> The blocks beyond i_size will never be written, there won't be any valid message
> >>>> there, so we don't need to worry about that.
> >>>
> >>> I don't think we have a way to guarantee the order of i_size and block
> >>> allocation in f2fs. See f2fs_write_begin and f2fs_write_end.
> >>
> >> However, write_begin & write_end are covered by inode_lock, it could not be
> >> racy with inode size check in f2fs_sec_trim_file() as it hold inode_lock as
> >> well?
> >
> > Like Daeho said, write_begin -> checkpoint -> power-cut can give bigger i_blocks
> > than i_size.
>
> The path won't, cp only persists reserved block in dnode rather than written
> data block in segment, because data will be copied to page cache after write_begin.

Ah, you're talking about data validity, while I was doing block allocation in
this case. In either cases, I'd say secure_trim needs to trim whatever data
in valid block *address*.

>
> I think truncation path could as Daeho said:
>
> 1. truncate -> i_size update however blocks wasn't truncated yet -> checkpoint -> recovery
> 2. truncate failed -> i_size update however partial blocks was truncated -> fsync
>
> >
> >>
> >>>
> >>>>
> >>>> Thanks,
> >>>>
> >>>>> ending criteria?
> >>>>>
> >>>>>> + else
> >>>>>> + end_addr = range.start + range.len;
> >>>>>>
> >>>>>> to_end = (end_addr == inode->i_size);
> >>>>>> if (!IS_ALIGNED(range.start, F2FS_BLKSIZE) ||
> >>>>>> --
> >>>>>> 2.27.0.383.g050319c2ae-goog
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> _______________________________________________
> >>>>>> Linux-f2fs-devel mailing list
> >>>>>> Linux-f2fs-devel@lists.sourceforge.net
> >>>>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> >>>>>
> >>>>>
> >>>>> _______________________________________________
> >>>>> Linux-f2fs-devel mailing list
> >>>>> Linux-f2fs-devel@lists.sourceforge.net
> >>>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> >>>>> .
> >>>>>
> >>> .
> >>>
> > .
> >

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