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Date: Thu, 3 Sep 2020 10:05:01 +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] f2fs: change i_compr_blocks of inode to atomic
value
On 2020/9/3 9:43, Daeho Jeong wrote:
> And how about this atomic64 to just atomic?
> As you mentioned before, we don't need a 64bit value for
> i_compr_blocks of inode.
Yup, I think atomic type is enough for both f2fs_inode_info.i_compr_blocks and
f2fs_sb_info.compr_blocks.
Thanks,
>
> 2020년 9월 3일 (목) 오전 10:08, Chao Yu <yuchao0@...wei.com>님이 작성:
>>
>> On 2020/9/2 14:29, Daeho Jeong wrote:
>>> From: Daeho Jeong <daehojeong@...gle.com>
>>>
>>> writepages() can be concurrently invoked for the same file by different
>>> threads such as a thread fsyncing the file and a kworker kernel thread.
>>> So, changing i_compr_blocks without protection is racy and we need to
>>> protect it by changing it with atomic type value.
>>>
>>> Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
>>> ---
>>> fs/f2fs/f2fs.h | 15 +++++++++------
>>> fs/f2fs/file.c | 18 ++++++++++--------
>>> fs/f2fs/inode.c | 11 +++++++----
>>> fs/f2fs/super.c | 1 +
>>> 4 files changed, 27 insertions(+), 18 deletions(-)
>>>
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index f60414805e05..633957e14944 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -801,7 +801,7 @@ struct f2fs_inode_info {
>>> struct timespec64 i_disk_time[4];/* inode disk times */
>>>
>>> /* for file compress */
>>> - u64 i_compr_blocks; /* # of compressed blocks */
>>> + atomic64_t i_compr_blocks; /* # of compressed blocks */
>>> unsigned char i_compress_algorithm; /* algorithm type */
>>> unsigned char i_log_cluster_size; /* log of cluster size */
>>> unsigned int i_cluster_size; /* cluster size */
>>> @@ -3933,14 +3933,16 @@ static inline void set_compress_context(struct inode *inode)
>>> static inline u64 f2fs_disable_compressed_file(struct inode *inode)
>>> {
>>> struct f2fs_inode_info *fi = F2FS_I(inode);
>>> + u64 i_compr_blocks;
>>>
>>> if (!f2fs_compressed_file(inode))
>>> return 0;
>>> if (S_ISREG(inode->i_mode)) {
>>> if (get_dirty_pages(inode))
>>> return 1;
>>> - if (fi->i_compr_blocks)
>>> - return fi->i_compr_blocks;
>> Caller doesn't care how many compr_blocks this inode has saved, so we can just
>> return 1 here.
>>
>>> + i_compr_blocks = atomic64_read(&fi->i_compr_blocks);
>>> + if (i_compr_blocks)
>>> + return i_compr_blocks;
>>> }
>>>
>>> fi->i_flags &= ~F2FS_COMPR_FL;
>>> @@ -4057,16 +4059,17 @@ static inline void f2fs_i_compr_blocks_update(struct inode *inode,
>>> u64 blocks, bool add)
>>> {
>>> int diff = F2FS_I(inode)->i_cluster_size - blocks;
>>> + struct f2fs_inode_info *fi = F2FS_I(inode);
>>>
>>> /* don't update i_compr_blocks if saved blocks were released */
>>> - if (!add && !F2FS_I(inode)->i_compr_blocks)
>>> + if (!add && !atomic64_read(&fi->i_compr_blocks))
>>> return;
>>>
>>> if (add) {
>>> - F2FS_I(inode)->i_compr_blocks += diff;
>>> + atomic64_add(diff, &fi->i_compr_blocks);
>>> stat_add_compr_blocks(inode, diff);
>>> } else {
>>> - F2FS_I(inode)->i_compr_blocks -= diff;
>>> + atomic64_sub(diff, &fi->i_compr_blocks);
>>> stat_sub_compr_blocks(inode, diff);
>>> }
>>> f2fs_mark_inode_dirty_sync(inode, true);
>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>> index cc7f5670390f..4e4e369b97e5 100644
>>> --- a/fs/f2fs/file.c
>>> +++ b/fs/f2fs/file.c
>>> @@ -564,7 +564,7 @@ void f2fs_truncate_data_blocks_range(struct dnode_of_data *dn, int count)
>>> bool compressed_cluster = false;
>>> int cluster_index = 0, valid_blocks = 0;
>>> int cluster_size = F2FS_I(dn->inode)->i_cluster_size;
>>> - bool released = !F2FS_I(dn->inode)->i_compr_blocks;
>>> + bool released = !atomic64_read(&F2FS_I(dn->inode)->i_compr_blocks);
>>>
>>> if (IS_INODE(dn->node_page) && f2fs_has_extra_attr(dn->inode))
>>> base = get_extra_isize(dn->inode);
>>> @@ -3436,7 +3436,7 @@ static int f2fs_get_compress_blocks(struct file *filp, unsigned long arg)
>>> if (!f2fs_compressed_file(inode))
>>> return -EINVAL;
>>>
>>> - blocks = F2FS_I(inode)->i_compr_blocks;
>>> + blocks = atomic64_read(&F2FS_I(inode)->i_compr_blocks);
>>> return put_user(blocks, (u64 __user *)arg);
>>> }
>>>
>>> @@ -3535,7 +3535,7 @@ static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg)
>>> if (ret)
>>> goto out;
>>>
>>> - if (!F2FS_I(inode)->i_compr_blocks)
>>> + if (!atomic64_read(&F2FS_I(inode)->i_compr_blocks))
>>> goto out;
>>>
>>> F2FS_I(inode)->i_flags |= F2FS_IMMUTABLE_FL;
>>> @@ -3588,14 +3588,15 @@ static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg)
>>>
>>> if (ret >= 0) {
>>> ret = put_user(released_blocks, (u64 __user *)arg);
>>> - } else if (released_blocks && F2FS_I(inode)->i_compr_blocks) {
>>> + } else if (released_blocks &&
>>> + atomic64_read(&F2FS_I(inode)->i_compr_blocks)) {
>>> set_sbi_flag(sbi, SBI_NEED_FSCK);
>>> f2fs_warn(sbi, "%s: partial blocks were released i_ino=%lx "
>>> "iblocks=%llu, released=%u, compr_blocks=%llu, "
>>> "run fsck to fix.",
>>> __func__, inode->i_ino, inode->i_blocks,
>>> released_blocks,
>>> - F2FS_I(inode)->i_compr_blocks);
>>> + atomic64_read(&F2FS_I(inode)->i_compr_blocks));
>>> }
>>>
>>> return ret;
>>> @@ -3683,7 +3684,7 @@ static int f2fs_reserve_compress_blocks(struct file *filp, unsigned long arg)
>>> if (ret)
>>> return ret;
>>>
>>> - if (F2FS_I(inode)->i_compr_blocks)
>>> + if (atomic64_read(&F2FS_I(inode)->i_compr_blocks))
>>> goto out;
>>>
>>> f2fs_balance_fs(F2FS_I_SB(inode), true);
>>> @@ -3747,14 +3748,15 @@ static int f2fs_reserve_compress_blocks(struct file *filp, unsigned long arg)
>>>
>>> if (ret >= 0) {
>>> ret = put_user(reserved_blocks, (u64 __user *)arg);
>>> - } else if (reserved_blocks && F2FS_I(inode)->i_compr_blocks) {
>>> + } else if (reserved_blocks &&
>>> + atomic64_read(&F2FS_I(inode)->i_compr_blocks)) {
>>> set_sbi_flag(sbi, SBI_NEED_FSCK);
>>> f2fs_warn(sbi, "%s: partial blocks were released i_ino=%lx "
>>> "iblocks=%llu, reserved=%u, compr_blocks=%llu, "
>>> "run fsck to fix.",
>>> __func__, inode->i_ino, inode->i_blocks,
>>> reserved_blocks,
>>> - F2FS_I(inode)->i_compr_blocks);
>>> + atomic64_read(&F2FS_I(inode)->i_compr_blocks));
>>> }
>>>
>>> return ret;
>>> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
>>> index 66969ae852b9..e86857af9699 100644
>>> --- a/fs/f2fs/inode.c
>>> +++ b/fs/f2fs/inode.c
>>> @@ -442,7 +442,8 @@ static int do_read_inode(struct inode *inode)
>>> (fi->i_flags & F2FS_COMPR_FL)) {
>>> if (F2FS_FITS_IN_INODE(ri, fi->i_extra_isize,
>>> i_log_cluster_size)) {
>>> - fi->i_compr_blocks = le64_to_cpu(ri->i_compr_blocks);
>>> + atomic64_set(&fi->i_compr_blocks,
>>> + le64_to_cpu(ri->i_compr_blocks));
>>> fi->i_compress_algorithm = ri->i_compress_algorithm;
>>> fi->i_log_cluster_size = ri->i_log_cluster_size;
>>> fi->i_cluster_size = 1 << fi->i_log_cluster_size;
>>> @@ -460,7 +461,7 @@ static int do_read_inode(struct inode *inode)
>>> stat_inc_inline_inode(inode);
>>> stat_inc_inline_dir(inode);
>>> stat_inc_compr_inode(inode);
>>> - stat_add_compr_blocks(inode, F2FS_I(inode)->i_compr_blocks);
>>> + stat_add_compr_blocks(inode, atomic64_read(&fi->i_compr_blocks));
>>>
>>> return 0;
>>> }
>>> @@ -619,7 +620,8 @@ void f2fs_update_inode(struct inode *inode, struct page *node_page)
>>> F2FS_FITS_IN_INODE(ri, F2FS_I(inode)->i_extra_isize,
>>> i_log_cluster_size)) {
>>> ri->i_compr_blocks =
>>> - cpu_to_le64(F2FS_I(inode)->i_compr_blocks);
>>> + cpu_to_le64(atomic64_read(
>>> + &F2FS_I(inode)->i_compr_blocks));
>>> ri->i_compress_algorithm =
>>> F2FS_I(inode)->i_compress_algorithm;
>>> ri->i_log_cluster_size =
>>> @@ -768,7 +770,8 @@ void f2fs_evict_inode(struct inode *inode)
>>> stat_dec_inline_dir(inode);
>>> stat_dec_inline_inode(inode);
>>> stat_dec_compr_inode(inode);
>>> - stat_sub_compr_blocks(inode, F2FS_I(inode)->i_compr_blocks);
>>> + stat_sub_compr_blocks(inode,
>>> + atomic64_read(&F2FS_I(inode)->i_compr_blocks));
>>>
>>> if (likely(!f2fs_cp_error(sbi) &&
>>> !is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>> index 83bf9a02f83f..65613500e1ab 100644
>>> --- a/fs/f2fs/super.c
>>> +++ b/fs/f2fs/super.c
>>> @@ -1011,6 +1011,7 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb)
>>>
>>> /* Initialize f2fs-specific inode info */
>>> atomic_set(&fi->dirty_pages, 0);
>>> + atomic64_set(&fi->i_compr_blocks, 0);
>>> init_rwsem(&fi->i_sem);
>>> spin_lock_init(&fi->i_size_lock);
>>> INIT_LIST_HEAD(&fi->dirty_list);
>>>
> .
>
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