Re: [PATCH v3] f2fs: add fast symlink support

From: Wanpeng Li
Date: Sun Mar 22 2015 - 19:28:25 EST


Hi Jaegeuk,
On Fri, Mar 20, 2015 at 01:13:39PM -0700, Jaegeuk Kim wrote:
>Hi Wanpeng,
>
>The Chao's patch is what I intended.
>
>Could anyone of you enhance that patch?
>If we use inline_data by default, we need another option to disable it.
>Like "noinline_data"?

Will do, thanks for you and Chao's help.

Regards,
Wanpeng Li

>
>Thanks,
>
>On Thu, Mar 19, 2015 at 11:17:17AM +0800, Chao Yu wrote:
>> Hi Wanpeng,
>>
>> > -----Original Message-----
>> > From: Wanpeng Li [mailto:wanpeng.li@xxxxxxxxxxxxxxx]
>> > Sent: Thursday, March 19, 2015 7:02 AM
>> > To: Jaegeuk Kim
>> > Cc: Wanpeng Li; Changman Lee; Chao Yu; linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx;
>> > linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
>> > Subject: Re: [PATCH v3] f2fs: add fast symlink support
>> >
>> > Hi Jaegeuk,
>> > On Wed, Mar 18, 2015 at 11:05:28AM -0700, Jaegeuk Kim wrote:
>> > >Hi,
>> > >
>> > >On Wed, Mar 18, 2015 at 04:58:52PM +0800, Wanpeng Li wrote:
>> > >> Hi Jaegeuk,
>> > >> On Tue, Mar 17, 2015 at 10:21:27AM -0700, Jaegeuk Kim wrote:
>> > >> >> - err = page_symlink(inode, symname, symlen);
>> > >> >> +
>> > >> >> + if (symlen > MAX_FAST_SYMLINK_SIZE) {
>> > >> >> + /* slow symlink */
>> > >> >> + inode->i_op = &f2fs_symlink_inode_operations;
>> > >> >> + inode->i_mapping->a_ops = &f2fs_dblock_aops;
>> > >> >> + err = page_symlink(inode, symname, symlen);
>> > >> >> + } else {
>> > >> >> + /* fast symlink */
>> > >> >> + struct page *node_page;
>> > >> >> +
>> > >> >> + inode->i_op = &f2fs_fast_symlink_inode_operations;
>> > >> >> + node_page = get_node_page(sbi, inode->i_ino);
>> > >> >> + memcpy((char *)&F2FS_INODE(node_page)->i_addr, symname, symlen);
>> > >> >
>> > >> >This is mostly likewise the inline_data flow.
>> > >> >As of now, I can't recommend using any i_addr region, since we need to handle
>> > >> >many cases such as truncation, roll-forward recovery, and fsck/dump tools.
>> > >> >
>> > >> >It is more sensible to enable inline_data by default, isn't it?
>> > >>
>> > >> Do you mean to replace the codes above by something like
>> > >> f2fs_write_inline_data()?
>> > >
>> > >I meant the mount option, inline_data.
>> > >Currently, f2fs doesn't set that option at mount time, but I thought that we
>> > >can set it by default since it becomes stable.
>> >
>> > So I think you mean my codes should memcpy i_addr[1~872] instead of i_addr[0~872], right?
>>
>> I think what Jaegeuk means is that we can use inline_data in f2fs by default with
>> patch like below firstly:
>>
>> >From a7320bfe94239ea4ceb193621a3a1a4d11a40d07 Mon Sep 17 00:00:00 2001
>> From: Chao Yu <chao2.yu@xxxxxxxxxxx>
>> Date: Thu, 19 Mar 2015 10:02:08 +0800
>> Subject: [PATCH] f2fs: use inline_data by default
>>
>> Use inline_data feature by default since it brings us better performance & space
>> utilization and now it is already stable.
>>
>> Suggested-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
>> Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx>
>> Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
>> ---
>> fs/f2fs/super.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>> index fc6857f..8772d91 100644
>> --- a/fs/f2fs/super.c
>> +++ b/fs/f2fs/super.c
>> @@ -991,6 +991,7 @@ try_onemore:
>> sbi->active_logs = NR_CURSEG_TYPE;
>>
>> set_opt(sbi, BG_GC);
>> + set_opt(sbi, INLINE_DATA);
>>
>> #ifdef CONFIG_F2FS_FS_XATTR
>> set_opt(sbi, XATTR_USER);
>> --
>> 2.3.1
>>
>> Then we enable inline_data feature for symlink in f2fs_may_inline, after that
>> by default our symlink created has inline_data flag in it, we treat small size
>> symlink as an inline regular file, we can write its data page which is written
>> in page_symlink into inode page like normal inline data procedure.
>>
>> Thanks,
>>
>> >
>> > Regards,
>> > Wanpeng Li
>> >
>> > >
>> > >Thanks,
>> > >
>> > >>
>> > >> Regards,
>> > >> Wanpeng Li
>> > >>
>> > >> >
>> > >> >Thanks,
>> > >> >
>> > >> >> + set_page_dirty(node_page);
>> > >> >> + f2fs_put_page(node_page, 1);
>> > >> >> + inode->i_size = symlen-1;
>> > >> >> + set_inode_flag(F2FS_I(inode), FI_FAST_SYMLINK);
>> > >> >> + mark_inode_dirty(inode);
>> > >> >> + }
>> > >> >> alloc_nid_done(sbi, inode->i_ino);
>> > >> >>
>> > >> >> d_instantiate(dentry, inode);
>> > >> >> @@ -743,6 +774,20 @@ const struct inode_operations f2fs_symlink_inode_operations = {
>> > >> >> #endif
>> > >> >> };
>> > >> >>
>> > >> >> +const struct inode_operations f2fs_fast_symlink_inode_operations = {
>> > >> >> + .readlink = generic_readlink,
>> > >> >> + .follow_link = f2fs_follow_link,
>> > >> >> + .put_link = page_put_link,
>> > >> >> + .getattr = f2fs_getattr,
>> > >> >> + .setattr = f2fs_setattr,
>> > >> >> +#ifdef CONFIG_F2FS_FS_XATTR
>> > >> >> + .setxattr = generic_setxattr,
>> > >> >> + .getxattr = generic_getxattr,
>> > >> >> + .listxattr = f2fs_listxattr,
>> > >> >> + .removexattr = generic_removexattr,
>> > >> >> +#endif
>> > >> >> +};
>> > >> >> +
>> > >> >> const struct inode_operations f2fs_special_inode_operations = {
>> > >> >> .getattr = f2fs_getattr,
>> > >> >> .setattr = f2fs_setattr,
>> > >> >> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>> > >> >> index 35a9117..efe28a2b 100644
>> > >> >> --- a/fs/f2fs/node.c
>> > >> >> +++ b/fs/f2fs/node.c
>> > >> >> @@ -908,8 +908,9 @@ void remove_inode_page(struct inode *inode)
>> > >> >> }
>> > >> >>
>> > >> >> /* remove potential inline_data blocks */
>> > >> >> - if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
>> > >> >> - S_ISLNK(inode->i_mode))
>> > >> >> + if ((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
>> > >> >> + S_ISLNK(inode->i_mode)) &&
>> > >> >> + !f2fs_inode_is_fast_symlink(inode))
>> > >> >> truncate_data_blocks_range(&dn, 1);
>> > >> >>
>> > >> >> /* 0 is possible, after f2fs_new_inode() has failed */
>> > >> >> diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
>> > >> >> index 502f28c..834880c 100644
>> > >> >> --- a/include/linux/f2fs_fs.h
>> > >> >> +++ b/include/linux/f2fs_fs.h
>> > >> >> @@ -178,9 +178,11 @@ struct f2fs_extent {
>> > >> >> #define F2FS_INLINE_DATA 0x02 /* file inline data flag */
>> > >> >> #define F2FS_INLINE_DENTRY 0x04 /* file inline dentry flag */
>> > >> >> #define F2FS_DATA_EXIST 0x08 /* file inline data exist flag */
>> > >> >> +#define F2FS_FAST_SYMLINK 0x10 /* file fast symlink flag */
>> > >> >>
>> > >> >> #define MAX_INLINE_DATA (sizeof(__le32) * (DEF_ADDRS_PER_INODE - \
>> > >> >> F2FS_INLINE_XATTR_ADDRS - 1))
>> > >> >> +#define MAX_FAST_SYMLINK_SIZE (MAX_INLINE_DATA + 1)
>> > >> >>
>> > >> >> struct f2fs_inode {
>> > >> >> __le16 i_mode; /* file mode */
>> > >> >> --
>> > >> >> 1.9.1
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