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SubjectRe: [PATCH v2] f2fs: separate NOCoW and pinfile semantics
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On 2019/7/29 13:57, Jaegeuk Kim wrote:
> On 07/23, Chao Yu wrote:
>> On 2019/7/23 10:36, Jaegeuk Kim wrote:
>>> On 07/19, Chao Yu wrote:
>>>> Pinning a file is heavy, because skipping pinned files make GC
>>>> running with heavy load or no effect.
>>>
>>> Pinned file is a part of NOCOW files, so I don't think we can simply drop it
>>> for backward compatibility.
>>
>> Yes,
>>
>> But what I concerned is that pin file is too heavy, so in order to satisfy below
>> demand, how about introducing pin_file_2 flag to triggering IPU only during
>> flush/writeback.
>
> That can be done by cold files?

Then it may inherit property of cold type file, e.g. a) goes into cold area; b)
update with very low frequency.

Actually pin_file_2 could be used by db-wal/log file, which are updated
frequently, and should go to hot/warm area, it does not match above two property.

Thank,

>
>>
>>>
>>>>
>>>> So that this patch propose to separate nocow and pinfile semantics:
>>>> - NOCoW flag can only be set on regular file.
>>>> - NOCoW file will only trigger IPU at common writeback/flush.
>>>> - NOCow file will do OPU during GC.
>>>>
>>>> For the demand of 1) avoid fragment of file's physical block and
>>>> 2) userspace don't care about file's specific physical address,
>>>> tagging file as NOCoW will be cheaper than pinned one.
>>
>> ^^^
>>
>> Thanks,
>>
>>>>
>>>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>>>> ---
>>>> v2:
>>>> - rebase code to fix compile error.
>>>> fs/f2fs/data.c | 3 ++-
>>>> fs/f2fs/f2fs.h | 1 +
>>>> fs/f2fs/file.c | 22 +++++++++++++++++++---
>>>> 3 files changed, 22 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>>> index a2a28bb269bf..15fb8954c363 100644
>>>> --- a/fs/f2fs/data.c
>>>> +++ b/fs/f2fs/data.c
>>>> @@ -1884,7 +1884,8 @@ static inline bool check_inplace_update_policy(struct inode *inode,
>>>>
>>>> bool f2fs_should_update_inplace(struct inode *inode, struct f2fs_io_info *fio)
>>>> {
>>>> - if (f2fs_is_pinned_file(inode))
>>>> + if (f2fs_is_pinned_file(inode) ||
>>>> + F2FS_I(inode)->i_flags & F2FS_NOCOW_FL)
>>>> return true;
>>>>
>>>> /* if this is cold file, we should overwrite to avoid fragmentation */
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index 596ab3e1dd7b..f6c5a3d2e659 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -2374,6 +2374,7 @@ static inline void f2fs_change_bit(unsigned int nr, char *addr)
>>>> #define F2FS_NOATIME_FL 0x00000080 /* do not update atime */
>>>> #define F2FS_INDEX_FL 0x00001000 /* hash-indexed directory */
>>>> #define F2FS_DIRSYNC_FL 0x00010000 /* dirsync behaviour (directories only) */
>>>> +#define F2FS_NOCOW_FL 0x00800000 /* Do not cow file */
>>>> #define F2FS_PROJINHERIT_FL 0x20000000 /* Create with parents projid */
>>>>
>>>> /* Flags that should be inherited by new inodes from their parent. */
>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>>> index 7ca545874060..ae0fec54cac6 100644
>>>> --- a/fs/f2fs/file.c
>>>> +++ b/fs/f2fs/file.c
>>>> @@ -1692,6 +1692,7 @@ static const struct {
>>>> { F2FS_NOATIME_FL, FS_NOATIME_FL },
>>>> { F2FS_INDEX_FL, FS_INDEX_FL },
>>>> { F2FS_DIRSYNC_FL, FS_DIRSYNC_FL },
>>>> + { F2FS_NOCOW_FL, FS_NOCOW_FL },
>>>> { F2FS_PROJINHERIT_FL, FS_PROJINHERIT_FL },
>>>> };
>>>>
>>>> @@ -1715,7 +1716,8 @@ static const struct {
>>>> FS_NODUMP_FL | \
>>>> FS_NOATIME_FL | \
>>>> FS_DIRSYNC_FL | \
>>>> - FS_PROJINHERIT_FL)
>>>> + FS_PROJINHERIT_FL | \
>>>> + FS_NOCOW_FL)
>>>>
>>>> /* Convert f2fs on-disk i_flags to FS_IOC_{GET,SET}FLAGS flags */
>>>> static inline u32 f2fs_iflags_to_fsflags(u32 iflags)
>>>> @@ -1753,8 +1755,6 @@ static int f2fs_ioc_getflags(struct file *filp, unsigned long arg)
>>>> fsflags |= FS_ENCRYPT_FL;
>>>> if (f2fs_has_inline_data(inode) || f2fs_has_inline_dentry(inode))
>>>> fsflags |= FS_INLINE_DATA_FL;
>>>> - if (is_inode_flag_set(inode, FI_PIN_FILE))
>>>> - fsflags |= FS_NOCOW_FL;
>>>>
>>>> fsflags &= F2FS_GETTABLE_FS_FL;
>>>>
>>>> @@ -1794,6 +1794,22 @@ static int f2fs_ioc_setflags(struct file *filp, unsigned long arg)
>>>> if (ret)
>>>> goto out;
>>>>
>>>> + if ((fsflags ^ old_fsflags) & FS_NOCOW_FL) {
>>>> + if (!S_ISREG(inode->i_mode)) {
>>>> + ret = -EINVAL;
>>>> + goto out;
>>>> + }
>>>> +
>>>> + if (f2fs_should_update_outplace(inode, NULL)) {
>>>> + ret = -EINVAL;
>>>> + goto out;
>>>> + }
>>>> +
>>>> + ret = f2fs_convert_inline_inode(inode);
>>>> + if (ret)
>>>> + goto out;
>>>> + }
>>>> +
>>>> ret = f2fs_setflags_common(inode, iflags,
>>>> f2fs_fsflags_to_iflags(F2FS_SETTABLE_FS_FL));
>>>> out:
>>>> --
>>>> 2.18.0.rc1
>>> .
>>>
> .
>

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