Re: [PATCH v2 1/4] f2fs: support F2FS_IOC_PRECACHE_EXTENTS
From: Chao Yu
Date: Thu Jan 11 2018 - 01:11:56 EST
On 2018/1/11 13:16, Jaegeuk Kim wrote:
> On 01/11, Chao Yu wrote:
>> On 2018/1/11 3:24, Jaegeuk Kim wrote:
>>> On 01/10, Chao Yu wrote:
>>>> This patch introduces a new ioctl F2FS_IOC_PRECACHE_EXTENTS to precache
>>>> extent info like ext4, in order to gain better performance during
>>>> triggering AIO by eliminating synchronous waiting of mapping info.
>>>>
>>>> Referred commit: 7869a4a6c5ca ("ext4: add support for extent pre-caching")
>>>>
>>>> In addition, with newly added extent precache abilitiy, this patch add
>>>> to support FIEMAP_FLAG_CACHE in ->fiemap.
>>>>
>>>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>>>> ---
>>>> v2:
>>>> - integrate extent precache related patches into this one.
>>>> fs/f2fs/data.c | 33 +++++++++++++++++++++++++++++++++
>>>> fs/f2fs/f2fs.h | 3 +++
>>>> fs/f2fs/file.c | 39 +++++++++++++++++++++++++++++++++++++++
>>>> 3 files changed, 75 insertions(+)
>>>>
>>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>>> index 8c05e9a74427..d7d3b2b49907 100644
>>>> --- a/fs/f2fs/data.c
>>>> +++ b/fs/f2fs/data.c
>>>> @@ -927,6 +927,7 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>>>> blkcnt_t prealloc;
>>>> struct extent_info ei = {0,0,0};
>>>> block_t blkaddr;
>>>> + unsigned int start_pgofs;
>>>>
>>>> if (!maxblocks)
>>>> return 0;
>>>> @@ -942,6 +943,8 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>>>> map->m_pblk = ei.blk + pgofs - ei.fofs;
>>>> map->m_len = min((pgoff_t)maxblocks, ei.fofs + ei.len - pgofs);
>>>> map->m_flags = F2FS_MAP_MAPPED;
>>>> + if (map->m_next_pgofs)
>>>> + *map->m_next_pgofs = pgofs + map->m_len;
>>>> goto out;
>>>> }
>>>>
>>>> @@ -964,6 +967,7 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>>>> goto unlock_out;
>>>> }
>>>>
>>>> + start_pgofs = pgofs;
>>>> prealloc = 0;
>>>> last_ofs_in_node = ofs_in_node = dn.ofs_in_node;
>>>> end_offset = ADDRS_PER_PAGE(dn.node_page, inode);
>>>> @@ -997,6 +1001,8 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>>>> map->m_pblk = 0;
>>>> goto sync_out;
>>>> }
>>>> + if (flag == F2FS_GET_BLOCK_PRECACHE)
>>>> + goto sync_out;
>>>> if (flag == F2FS_GET_BLOCK_FIEMAP &&
>>>> blkaddr == NULL_ADDR) {
>>>> if (map->m_next_pgofs)
>>>> @@ -1055,6 +1061,16 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>>>> else if (dn.ofs_in_node < end_offset)
>>>> goto next_block;
>>>>
>>>> + if (flag == F2FS_GET_BLOCK_PRECACHE) {
>>>> + if (map->m_flags & F2FS_MAP_MAPPED) {
>>>> + unsigned int ofs = start_pgofs - map->m_lblk;
>>>> +
>>>> + f2fs_update_extent_cache_range(&dn,
>>>> + start_pgofs, map->m_pblk + ofs,
>>>> + map->m_len - ofs);
>>>> + }
>>>> + }
>>>> +
>>>> f2fs_put_dnode(&dn);
>>>>
>>>> if (create) {
>>>> @@ -1064,6 +1080,17 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>>>> goto next_dnode;
>>>>
>>>> sync_out:
>>>> + if (flag == F2FS_GET_BLOCK_PRECACHE) {
>>>> + if (map->m_flags & F2FS_MAP_MAPPED) {
>>>> + unsigned int ofs = start_pgofs - map->m_lblk;
>>>> +
>>>> + f2fs_update_extent_cache_range(&dn,
>>>> + start_pgofs, map->m_pblk + ofs,
>>>> + map->m_len - ofs);
>>>> + }
>>>> + if (map->m_next_pgofs)
>>>> + *map->m_next_pgofs = pgofs + 1;
>>>> + }
>>>> f2fs_put_dnode(&dn);
>>>> unlock_out:
>>>> if (create) {
>>>> @@ -1210,6 +1237,12 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
>>>>
>>>> inode_lock(inode);
>>>>
>>>> + if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
>>>> + ret = f2fs_precache_extents(inode);
>>>
>>> We need to do inode_lock() in f2fs_precache_extents() after uncovering here?
>>
>>> Uh? We don't need to cover fiemap_check_flags() by inode_lock().
>>
>> Hmm, how about just following generic_block_fiemap using inode lock to
>> cover whole block_fiemap including fiemap_check_flags, that can avoid
>> leaving a hole in f2fs_fiemap after we add f2fs_precache_extents before
>> fiemap_check_flags.
>
> Do we really need inode_lock() for f2fs_precache_extents()? What about ioctl()
> then? I think we can precache extents like a salt to speed up actual fiemap, so
> we don't need inode_lock for that tho.
It looks leaving fiemap_check_flags and f2fs_precache_extents outside of
inode lock won't cause any issue so far, let me change it.
Thanks,
>
>>
>> Thanks,
>>
>>>
>>>> + if (ret)
>>>> + goto out;
>>>> + }
>>>> +
>>>> ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC | FIEMAP_FLAG_XATTR);
>>>> if (ret)
>>>> goto out;
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index 3b3ddcdc98e9..73a751cdbac1 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -359,6 +359,7 @@ static inline bool __has_cursum_space(struct f2fs_journal *journal,
>>>> struct f2fs_gc_range)
>>>> #define F2FS_IOC_GET_FEATURES _IOR(F2FS_IOCTL_MAGIC, 12, __u32)
>>>> #define F2FS_IOC_SET_PIN_FILE _IOW(F2FS_IOCTL_MAGIC, 13, __u32)
>>>> +#define F2FS_IOC_PRECACHE_EXTENTS _IO(F2FS_IOCTL_MAGIC, 14)
>>>>
>>>> #define F2FS_IOC_SET_ENCRYPTION_POLICY FS_IOC_SET_ENCRYPTION_POLICY
>>>> #define F2FS_IOC_GET_ENCRYPTION_POLICY FS_IOC_GET_ENCRYPTION_POLICY
>>>> @@ -564,6 +565,7 @@ enum {
>>>> F2FS_GET_BLOCK_BMAP,
>>>> F2FS_GET_BLOCK_PRE_DIO,
>>>> F2FS_GET_BLOCK_PRE_AIO,
>>>> + F2FS_GET_BLOCK_PRECACHE,
>>>> };
>>>>
>>>> /*
>>>> @@ -2567,6 +2569,7 @@ int f2fs_getattr(const struct path *path, struct kstat *stat,
>>>> int f2fs_setattr(struct dentry *dentry, struct iattr *attr);
>>>> int truncate_hole(struct inode *inode, pgoff_t pg_start, pgoff_t pg_end);
>>>> void truncate_data_blocks_range(struct dnode_of_data *dn, int count);
>>>> +int f2fs_precache_extents(struct inode *inode);
>>>> long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
>>>> long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
>>>> int f2fs_pin_file_control(struct inode *inode, bool inc);
>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>>> index e4078b32856c..6e30016f26ad 100644
>>>> --- a/fs/f2fs/file.c
>>>> +++ b/fs/f2fs/file.c
>>>> @@ -2734,6 +2734,42 @@ static int f2fs_ioc_set_pin_file(struct file *filp, unsigned long arg)
>>>> return ret;
>>>> }
>>>>
>>>> +int f2fs_precache_extents(struct inode *inode)
>>>> +{
>>>> + struct f2fs_inode_info *fi = F2FS_I(inode);
>>>> + struct f2fs_map_blocks map;
>>>> + pgoff_t next_pgofs;
>>>> + loff_t end;
>>>> + int err;
>>>> +
>>>> + if (is_inode_flag_set(inode, FI_NO_EXTENT))
>>>> + return -EOPNOTSUPP;
>>>> +
>>>> + map.m_lblk = 0;
>>>> + map.m_next_pgofs = &next_pgofs;
>>>> + map.m_seg_type = NO_CHECK_TYPE;
>>>> + end = F2FS_I_SB(inode)->max_file_blocks;
>>>> +
>>>> + while (map.m_lblk < end) {
>>>> + map.m_len = end - map.m_lblk;
>>>> +
>>>> + down_write(&fi->dio_rwsem[WRITE]);
>>>> + err = f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_PRECACHE);
>>>> + up_write(&fi->dio_rwsem[WRITE]);
>>>> + if (err)
>>>> + return err;
>>>> +
>>>> + map.m_lblk = next_pgofs;
>>>> + }
>>>> +
>>>> + return err;
>>>> +}
>>>> +
>>>> +static int f2fs_ioc_precache_extents(struct file *filp, unsigned long arg)
>>>> +{
>>>> + return f2fs_precache_extents(file_inode(filp));
>>>> +}
>>>> +
>>>> long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>>>> {
>>>> if (unlikely(f2fs_cp_error(F2FS_I_SB(file_inode(filp)))))
>>>> @@ -2786,6 +2822,8 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>>>> return f2fs_ioc_fssetxattr(filp, arg);
>>>> case F2FS_IOC_SET_PIN_FILE:
>>>> return f2fs_ioc_set_pin_file(filp, arg);
>>>> + case F2FS_IOC_PRECACHE_EXTENTS:
>>>> + return f2fs_ioc_precache_extents(filp, arg);
>>>> default:
>>>> return -ENOTTY;
>>>> }
>>>> @@ -2862,6 +2900,7 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>>>> case F2FS_IOC_FSGETXATTR:
>>>> case F2FS_IOC_FSSETXATTR:
>>>> case F2FS_IOC_SET_PIN_FILE:
>>>> + case F2FS_IOC_PRECACHE_EXTENTS:
>>>> break;
>>>> default:
>>>> return -ENOIOCTLCMD;
>>>> --
>>>> 2.15.0.55.gc2ece9dc4de6
>>>
>>> .
>>>
>
> .
>