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Date: Thu, 24 Nov 2022 23:12:21 +0800
From: Chao Yu <chao@...nel.org>
To: Jaegeuk Kim <jaegeuk@...nel.org>
Cc: Daeho Jeong <daeho43@...il.com>, 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 v7] f2fs: introduce
F2FS_IOC_START_ATOMIC_REPLACE
On 2022/11/24 5:58, Jaegeuk Kim wrote:
> On 11/23, Chao Yu wrote:
>> On 2022/11/12 1:04, Daeho Jeong wrote:
>>> From: Daeho Jeong <daehojeong@...gle.com>
>>>
>>> introduce a new ioctl to replace the whole content of a file atomically,
>>> which means it induces truncate and content update at the same time.
>>> We can start it with F2FS_IOC_START_ATOMIC_REPLACE and complete it with
>>> F2FS_IOC_COMMIT_ATOMIC_WRITE. Or abort it with
>>> F2FS_IOC_ABORT_ATOMIC_WRITE.
>>>
>>> Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
>>> ---
>>> v7: changed where to clear FI_ATOMIC_REPLACE
>>> fixed tentative race condition in f2fs_ioc_start_atomic_write()
>>> v3: move i_size change after setting atomic write flag
>>> v2: add undefined ioctl number reported by <lkp@...el.com>
>>> ---
>>> fs/f2fs/data.c | 3 +++
>>> fs/f2fs/f2fs.h | 1 +
>>> fs/f2fs/file.c | 21 +++++++++++++++------
>>> fs/f2fs/segment.c | 13 ++++++++++++-
>>> include/uapi/linux/f2fs.h | 1 +
>>> 5 files changed, 32 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>> index 5f895ddcd64a..bce4dcc3ad78 100644
>>> --- a/fs/f2fs/data.c
>>> +++ b/fs/f2fs/data.c
>>> @@ -3457,6 +3457,9 @@ static int prepare_atomic_write_begin(struct f2fs_sb_info *sbi,
>>> else if (*blk_addr != NULL_ADDR)
>>> return 0;
>>> + if (is_inode_flag_set(inode, FI_ATOMIC_REPLACE))
>>> + goto reserve_block;
>>> +
>>> /* Look for the block in the original inode */
>>> err = __find_data_block(inode, index, &ori_blk_addr);
>>> if (err)
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index e29f9adf60ca..d513ecd17550 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -765,6 +765,7 @@ enum {
>>> FI_ALIGNED_WRITE, /* enable aligned write */
>>> FI_COW_FILE, /* indicate COW file */
>>> FI_ATOMIC_COMMITTED, /* indicate atomic commit completed except disk sync */
>>> + FI_ATOMIC_REPLACE, /* indicate atomic replace */
>>> FI_MAX, /* max flag, never be used */
>>> };
>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>> index 7ce629c95f4a..f9a04f6d76cb 100644
>>> --- a/fs/f2fs/file.c
>>> +++ b/fs/f2fs/file.c
>>> @@ -1984,7 +1984,7 @@ static int f2fs_ioc_getversion(struct file *filp, unsigned long arg)
>>> return put_user(inode->i_generation, (int __user *)arg);
>>> }
>>> -static int f2fs_ioc_start_atomic_write(struct file *filp)
>>> +static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
>>> {
>>> struct inode *inode = file_inode(filp);
>>> struct user_namespace *mnt_userns = file_mnt_user_ns(filp);
>>> @@ -2053,15 +2053,22 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
>>> f2fs_write_inode(inode, NULL);
>>> - isize = i_size_read(inode);
>>> - fi->original_i_size = isize;
>>> - f2fs_i_size_write(fi->cow_inode, isize);
>>> -
>>> stat_inc_atomic_inode(inode);
>>> set_inode_flag(inode, FI_ATOMIC_FILE);
>>> set_inode_flag(fi->cow_inode, FI_COW_FILE);
>>> clear_inode_flag(fi->cow_inode, FI_INLINE_DATA);
>>> +
>>> + isize = i_size_read(inode);
>>> + fi->original_i_size = isize;
>>> + if (truncate) {
>>> + set_inode_flag(inode, FI_ATOMIC_REPLACE);
>>> + truncate_inode_pages_final(inode->i_mapping);
>>> + f2fs_i_size_write(inode, 0);
>>> + isize = 0;
>>> + }
>>> + f2fs_i_size_write(fi->cow_inode, isize);
>>> +
>>> f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
>>> f2fs_update_time(sbi, REQ_TIME);
>>> @@ -4089,7 +4096,9 @@ static long __f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>>> case FS_IOC_GETVERSION:
>>> return f2fs_ioc_getversion(filp, arg);
>>> case F2FS_IOC_START_ATOMIC_WRITE:
>>> - return f2fs_ioc_start_atomic_write(filp);
>>> + return f2fs_ioc_start_atomic_write(filp, false);
>>> + case F2FS_IOC_START_ATOMIC_REPLACE:
>>> + return f2fs_ioc_start_atomic_write(filp, true);
>>> case F2FS_IOC_COMMIT_ATOMIC_WRITE:
>>> return f2fs_ioc_commit_atomic_write(filp);
>>> case F2FS_IOC_ABORT_ATOMIC_WRITE:
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 9cbf88092c78..f2930fffbc7d 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -197,6 +197,7 @@ void f2fs_abort_atomic_write(struct inode *inode, bool clean)
>>> fi->cow_inode = NULL;
>>> release_atomic_write_cnt(inode);
>>> clear_inode_flag(inode, FI_ATOMIC_COMMITTED);
>>> + clear_inode_flag(inode, FI_ATOMIC_REPLACE);
>>> clear_inode_flag(inode, FI_ATOMIC_FILE);
>>> stat_dec_atomic_inode(inode);
>>> @@ -261,14 +262,24 @@ static void __complete_revoke_list(struct inode *inode, struct list_head *head,
>>> bool revoke)
>>> {
>>> struct revoke_entry *cur, *tmp;
>>> + pgoff_t start_index = 0;
>>> + bool truncate = is_inode_flag_set(inode, FI_ATOMIC_REPLACE);
>>> list_for_each_entry_safe(cur, tmp, head, list) {
>>> - if (revoke)
>>> + if (revoke) {
>>> __replace_atomic_write_block(inode, cur->index,
>>> cur->old_addr, NULL, true);
>>> + } else if (truncate) {
>>> + f2fs_truncate_hole(inode, start_index, cur->index);
>>> + start_index = cur->index + 1;
>>
>> Do we try to truncate from page #0 to page #(index of last page in chain)?
>>
>> If so, how about calling f2fs_truncate_hole(, 0, last_index) after the loop?
>
> I think either would be fine. Could you please send a separate patch for this?
Fine, let me add a new patch to clean up it.
Reviewed-by: Chao Yu <chao@...nel.org>
Thanks,
>
>>
>> Thanks,
>>
>>> + }
>>> +
>>> list_del(&cur->list);
>>> kmem_cache_free(revoke_entry_slab, cur);
>>> }
>>> +
>>> + if (!revoke && truncate)
>>> + f2fs_do_truncate_blocks(inode, start_index * PAGE_SIZE, false);
>>> }
>>> static int __f2fs_commit_atomic_write(struct inode *inode)
>>> diff --git a/include/uapi/linux/f2fs.h b/include/uapi/linux/f2fs.h
>>> index 3121d127d5aa..955d440be104 100644
>>> --- a/include/uapi/linux/f2fs.h
>>> +++ b/include/uapi/linux/f2fs.h
>>> @@ -42,6 +42,7 @@
>>> struct f2fs_comp_option)
>>> #define F2FS_IOC_DECOMPRESS_FILE _IO(F2FS_IOCTL_MAGIC, 23)
>>> #define F2FS_IOC_COMPRESS_FILE _IO(F2FS_IOCTL_MAGIC, 24)
>>> +#define F2FS_IOC_START_ATOMIC_REPLACE _IO(F2FS_IOCTL_MAGIC, 25)
>>> /*
>>> * should be same as XFS_IOC_GOINGDOWN.
>>
>>
>> _______________________________________________
>> Linux-f2fs-devel mailing list
>> Linux-f2fs-devel@...ts.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
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