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Date: Thu, 26 Nov 2020 14:54:05 +0800
From: Chao Yu <yuchao0@...wei.com>
To: Daeho Jeong <daeho43@...il.com>
CC: <linux-kernel@...r.kernel.org>,
<linux-f2fs-devel@...ts.sourceforge.net>,
<kernel-team@...roid.com>, Daeho Jeong <daehojeong@...gle.com>
Subject: Re: [f2fs-dev] [PATCH 2/2] f2fs: add F2FS_IOC_DECOMPRESS_FILE and
F2FS_IOC_COMPRESS_FILE
Daeho,
On 2020/11/26 14:35, Daeho Jeong wrote:
> Chao,
>
>> A little bit wired, why not failing cluster_may_compress() for user mode, and
>> let writepages write cluster as raw blocks, in-where we can update i_compr_blocks
>> and global compr block stats correctly.
>
> For decompression ioctl, I've made f2fs_need_compress_data() return
> "false" to prevent compression write, so we don't use
> f2fs_write_compressed_pages() anymore in this case.
> Because of this, I manually updated i_compr_blocks. Do you have any
> suggestions on this?
I meant, we can control condition to call into below stack, then i_compr_blocks
can be updated correctly.
- f2fs_ioc_decompress_file
- writepages
- f2fs_write_multi_pages
- cluster_may_compress return false when ioc_decompress is in-process.
- f2fs_write_raw_pages
- f2fs_do_write_data_page
- f2fs_i_compr_blocks_update
Thanks,
>
> 2020년 11월 26일 (목) 오후 2:04, Daeho Jeong <daeho43@...il.com>님이 작성:
>>
>> Eric,
>>
>> do_page_cache_ra() is defined in mm/internal.h for internal use
>> between in mm, so we cannot use this one right now.
>> So, I think we could use page_cache_ra_unbounded(), because we already
>> check i_size boundary on our own.
>> What do you think?
>>
>> 2020년 11월 24일 (화) 오후 12:05, Chao Yu <yuchao0@...wei.com>님이 작성:
>>>
>>> On 2020/11/23 11:17, Daeho Jeong wrote:
>>>> From: Daeho Jeong <daehojeong@...gle.com>
>>>>
>>>> Added two ioctl to decompress/compress explicitly the compression
>>>> enabled file in "compress_mode=user-based" mount option.
>>>>
>>>> Using these two ioctls, the users can make a control of compression
>>>> and decompression of their files.
>>>>
>>>> Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
>>>> ---
>>>> fs/f2fs/file.c | 181 +++++++++++++++++++++++++++++++++++++-
>>>> include/uapi/linux/f2fs.h | 2 +
>>>> 2 files changed, 182 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>>> index be8db06aca27..e8f142470e87 100644
>>>> --- a/fs/f2fs/file.c
>>>> +++ b/fs/f2fs/file.c
>>>> @@ -4026,6 +4026,180 @@ static int f2fs_ioc_set_compress_option(struct file *filp, unsigned long arg)
>>>> return ret;
>>>> }
>>>>
>>>> +static int redirty_blocks(struct inode *inode, pgoff_t page_idx, int len)
>>>> +{
>>>> + DEFINE_READAHEAD(ractl, NULL, inode->i_mapping, page_idx);
>>>> + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>>> + struct address_space *mapping = inode->i_mapping;
>>>> + struct page *page;
>>>> + pgoff_t redirty_idx = page_idx;
>>>> + int i, page_len = 0, ret = 0;
>>>> +
>>>> + page_cache_ra_unbounded(&ractl, len, 0);
>>>> +
>>>> + for (i = 0; i < len; i++, page_idx++) {
>>>> + page = read_cache_page(mapping, page_idx, NULL, NULL);
>>>> + if (IS_ERR(page)) {
>>>> + ret = PTR_ERR(page);
>>>> + f2fs_warn(sbi, "%s: inode (%lu) : page_index (%lu) "
>>>> + "couldn't be read (errno:%d).\n",
>>>> + __func__, inode->i_ino, page_idx, ret);
>>>
>>> This is a common error case during calling read_cache_page(), IMO, this looks
>>> more like a debug log, so I prefer to print nothing here, or at least using
>>> f2fs_debug() instead.
>>>
>>>> + break;
>>>> + }
>>>> + page_len++;
>>>> + }
>>>> +
>>>> + for (i = 0; i < page_len; i++, redirty_idx++) {
>>>> + page = find_lock_page(mapping, redirty_idx);
>>>> + if (!page) {
>>>> + ret = -ENOENT;
>>>> + f2fs_warn(sbi, "%s: inode (%lu) : page_index (%lu) "
>>>> + "couldn't be found (errno:%d).\n",
>>>> + __func__, inode->i_ino, redirty_idx, ret);
>>>
>>> Ditto.
>>>
>>>> + }
>>>> + set_page_dirty(page);
>>>> + f2fs_put_page(page, 1);
>>>> + f2fs_put_page(page, 0);
>>>> + }
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> +static int f2fs_ioc_decompress_file(struct file *filp, unsigned long arg)
>>>> +{
>>>> + struct inode *inode = file_inode(filp);
>>>> + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>>> + struct f2fs_inode_info *fi = F2FS_I(inode);
>>>> + pgoff_t page_idx = 0, last_idx;
>>>> + int cluster_size = F2FS_I(inode)->i_cluster_size;
>>>> + int count, ret;
>>>> +
>>>> + if (!f2fs_sb_has_compression(sbi))
>>>> + return -EOPNOTSUPP;
>>>> +
>>>> + if (!(filp->f_mode & FMODE_WRITE))
>>>> + return -EBADF;
>>>> +
>>>> + if (!f2fs_compressed_file(inode))
>>>> + return -EINVAL;
>>>
>>> Before compressubg/decompressing file, should we check whether current inode's
>>> compress algorithm backend is available in f2fs module?
>>>
>>>> +
>>>> + f2fs_balance_fs(F2FS_I_SB(inode), true);
>>>> +
>>>> + file_start_write(filp);
>>>> + inode_lock(inode);
>>>> +
>>>> + if (f2fs_is_mmap_file(inode)) {
>>>> + ret = -EBUSY;
>>>> + goto out;
>>>> + }
>>>> +
>>>> + ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
>>>> + if (ret)
>>>> + goto out;
>>>> +
>>>> + if (!atomic_read(&fi->i_compr_blocks))
>>>> + goto out;
>>>> +
>>>> + last_idx = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
>>>> +
>>>> + count = last_idx - page_idx;
>>>> + while (count) {
>>>> + int len = min(cluster_size, count);
>>>> +
>>>> + ret = redirty_blocks(inode, page_idx, len);
>>>> +
>>>
>>> unneeded blank line..
>>>
>>>> + if (ret < 0)
>>>> + break;
>>>> +
>>>> + page_idx += len;
>>>> + count -= len;
>>>
>>> Considering there isn't so many memory in low-end device, how about calling
>>> filemap_fdatawrite() to writeback cluster after redirty several clusters
>>> or xxMB?
>>>
>>>> + }
>>>> +
>>>> + if (!ret)
>>>> + ret = filemap_write_and_wait_range(inode->i_mapping, 0,
>>>> + LLONG_MAX);
>>>> +
>>>> + if (!ret) {
>>>> + stat_sub_compr_blocks(inode, atomic_read(&fi->i_compr_blocks));
>>>> + atomic_set(&fi->i_compr_blocks, 0);
>>>> + f2fs_mark_inode_dirty_sync(inode, true);
>>>
>>> A little bit wired, why not failing cluster_may_compress() for user mode, and
>>> let writepages write cluster as raw blocks, in-where we can update i_compr_blocks
>>> and global compr block stats correctly.
>>>
>>>> + } else {
>>>> + f2fs_warn(sbi, "%s: The file might be partially decompressed "
>>>> + "(errno=%d). Please delete the file.\n",
>>>> + __func__, ret);
>>>> + }
>>>> +out:
>>>> + inode_unlock(inode);
>>>> + file_end_write(filp);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> +static int f2fs_ioc_compress_file(struct file *filp, unsigned long arg)
>>>> +{
>>>> + struct inode *inode = file_inode(filp);
>>>> + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>>> + pgoff_t page_idx = 0, last_idx;
>>>> + int cluster_size = F2FS_I(inode)->i_cluster_size;
>>>> + int count, ret;
>>>> +
>>>> + if (!f2fs_sb_has_compression(sbi))
>>>> + return -EOPNOTSUPP;
>>>> +
>>>> + if (!(filp->f_mode & FMODE_WRITE))
>>>> + return -EBADF;
>>>> +
>>>> + if (!f2fs_compressed_file(inode))
>>>> + return -EINVAL;
>>>
>>> algorithm backend check?
>>>
>>>> +
>>>> + f2fs_balance_fs(F2FS_I_SB(inode), true);
>>>> +
>>>> + file_start_write(filp);
>>>> + inode_lock(inode);
>>>> +
>>>> + if (f2fs_is_mmap_file(inode)) {
>>>> + ret = -EBUSY;
>>>> + goto out;
>>>> + }
>>>> +
>>>> + ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
>>>> + if (ret)
>>>> + goto out;
>>>> +
>>>> + set_inode_flag(inode, FI_ENABLE_COMPRESS);
>>>> +
>>>> + last_idx = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
>>>> +
>>>> + count = last_idx - page_idx;
>>>> + while (count) {
>>>> + int len = min(cluster_size, count);
>>>> +
>>>> + ret = redirty_blocks(inode, page_idx, len);
>>>> +
>>>
>>> Ditto.
>>>
>>> Thanks,
>>>
>>>> + if (ret < 0)
>>>> + break;
>>>> +
>>>> + page_idx += len;
>>>> + count -= len;
>>>> + }
>>>> +
>>>> + if (!ret)
>>>> + ret = filemap_write_and_wait_range(inode->i_mapping, 0,
>>>> + LLONG_MAX);
>>>> +
>>>> + clear_inode_flag(inode, FI_ENABLE_COMPRESS);
>>>> +
>>>> + if (ret)
>>>> + f2fs_warn(sbi, "%s: The file might be partially compressed "
>>>> + "(errno=%d). Please delete the file.\n",
>>>> + __func__, ret);
>>>> +out:
>>>> + inode_unlock(inode);
>>>> + file_end_write(filp);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> static long __f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>>>> {
>>>> switch (cmd) {
>>>> @@ -4113,6 +4287,10 @@ static long __f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>>>> return f2fs_ioc_get_compress_option(filp, arg);
>>>> case F2FS_IOC_SET_COMPRESS_OPTION:
>>>> return f2fs_ioc_set_compress_option(filp, arg);
>>>> + case F2FS_IOC_DECOMPRESS_FILE:
>>>> + return f2fs_ioc_decompress_file(filp, arg);
>>>> + case F2FS_IOC_COMPRESS_FILE:
>>>> + return f2fs_ioc_compress_file(filp, arg);
>>>> default:
>>>> return -ENOTTY;
>>>> }
>>>> @@ -4352,7 +4530,8 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>>>> case F2FS_IOC_SEC_TRIM_FILE:
>>>> case F2FS_IOC_GET_COMPRESS_OPTION:
>>>> case F2FS_IOC_SET_COMPRESS_OPTION:
>>>> - break;
>>>> + case F2FS_IOC_DECOMPRESS_FILE:
>>>> + case F2FS_IOC_COMPRESS_FILE:
>>>> default:
>>>> return -ENOIOCTLCMD;
>>>> }
>>>> diff --git a/include/uapi/linux/f2fs.h b/include/uapi/linux/f2fs.h
>>>> index f00199a2e38b..352a822d4370 100644
>>>> --- a/include/uapi/linux/f2fs.h
>>>> +++ b/include/uapi/linux/f2fs.h
>>>> @@ -40,6 +40,8 @@
>>>> struct f2fs_comp_option)
>>>> #define F2FS_IOC_SET_COMPRESS_OPTION _IOW(F2FS_IOCTL_MAGIC, 22, \
>>>> struct f2fs_comp_option)
>>>> +#define F2FS_IOC_DECOMPRESS_FILE _IO(F2FS_IOCTL_MAGIC, 23)
>>>> +#define F2FS_IOC_COMPRESS_FILE _IO(F2FS_IOCTL_MAGIC, 24)
>>>>
>>>> /*
>>>> * should be same as XFS_IOC_GOINGDOWN.
>>>>
> .
>
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