Re: [PATCH 1/4] f2fs: support F2FS_IOC_PRECACHE_EXTENTS
From: Jaegeuk Kim
Date: Tue Jan 09 2018 - 15:43:57 EST
On 01/09, Jaegeuk Kim wrote:
> On 01/08, Chao Yu wrote:
> > This patch introduces a new ioctl F2FS_IOC_PRECACHE_EXTENTS to precache
> > extent info, in order to gain better performance during data/meta
> > accessing.
> >
> > Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
> > ---
> > fs/f2fs/data.c | 27 +++++++++++++++++++++++++++
> > fs/f2fs/f2fs.h | 2 ++
> > fs/f2fs/file.c | 35 +++++++++++++++++++++++++++++++++++
> > 3 files changed, 64 insertions(+)
> >
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index 429764118604..f38e660bc889 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -920,6 +920,7 @@ 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;
> > @@ -935,6 +936,8 @@ 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;
> > }
> >
> > @@ -957,6 +960,7 @@ 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);
> > @@ -990,6 +994,8 @@ 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)
> > @@ -1048,6 +1054,16 @@ 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) {
> > @@ -1057,6 +1073,17 @@ 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) {
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 2f097139b8f7..14177cebc3e7 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -353,6 +353,7 @@ 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
> > @@ -558,6 +559,7 @@ enum {
> > F2FS_GET_BLOCK_BMAP,
> > F2FS_GET_BLOCK_PRE_DIO,
> > F2FS_GET_BLOCK_PRE_AIO,
> > + F2FS_GET_BLOCK_PRECACHE,
> > };
> >
> > /*
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index e4078b32856c..14e75871acf3 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -2734,6 +2734,38 @@ static int f2fs_ioc_set_pin_file(struct file *filp, unsigned long arg)
> > return ret;
> > }
> >
> > +static int f2fs_ioc_precache_extents(struct file *filp, unsigned long arg)
> > +{
> > + struct inode *inode = file_inode(filp);
> > + 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 0;
> > +}
> > +
> > 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 +2818,8 @@ 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:
>
> It looks like F2FS_IOC_CACHE_EXTENTS, and would be better to have an offset
> range to look up. BTW, if this is to prepare coming data reads, how about doing
> this through fadvise(POSIX_FADV_WILLNEED) instead of additional ioctl?
> It seems we can cache extents if the page is marked as PageReadahead().
Oh, I just got noticed that this just follows ext4 implementation. Please
write an integrated patch which introduces this with fiemap and adds description
regarding to ext4.
Thanks,
>
> Thanks,
>
> > + return f2fs_ioc_precache_extents(filp, arg);
> > default:
> > return -ENOTTY;
> > }
> > @@ -2862,6 +2896,7 @@ 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