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Message-ID: <20150317172127.GA745@jaegeuk-mac02>
Date: Tue, 17 Mar 2015 10:21:27 -0700
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: Wanpeng Li <wanpeng.li@...ux.intel.com>
Cc: Changman Lee <cm224.lee@...sung.com>,
Chao Yu <chao2.yu@...sung.com>,
linux-f2fs-devel@...ts.sourceforge.net,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] f2fs: add fast symlink support
Hi guys,
Sorry for the delay due to travel.
On Fri, Mar 13, 2015 at 02:33:39PM +0800, Wanpeng Li wrote:
> This patch introduces the improvement fast symlinks to allow storage of
> the target path within inode, thus symlinks with short target paths are
> more accessed quickly. It will fall back to using the original slow
> symlink if the target path exceeds the available inode space.
>
> Signed-off-by: Wanpeng Li <wanpeng.li@...ux.intel.com>
> ---
> v2 -> v3:
> * handle fast symlink in remove_inode_page
> v1 -> v2:
> * set max size of fast symlink according to inline_xattr flag
>
> fs/f2fs/f2fs.h | 15 ++++++++++++++
> fs/f2fs/file.c | 2 ++
> fs/f2fs/inode.c | 9 +++++++--
> fs/f2fs/namei.c | 53 +++++++++++++++++++++++++++++++++++++++++++++----
> fs/f2fs/node.c | 5 +++--
> include/linux/f2fs_fs.h | 2 ++
> 6 files changed, 78 insertions(+), 8 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 511d6cd..3012ea0 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1226,6 +1226,7 @@ enum {
> FI_VOLATILE_FILE, /* indicate volatile file */
> FI_DROP_CACHE, /* drop dirty page cache */
> FI_DATA_EXIST, /* indicate data exists */
> + FI_FAST_SYMLINK, /* indicate fast symlink */
> };
>
> static inline void set_inode_flag(struct f2fs_inode_info *fi, int flag)
> @@ -1262,6 +1263,8 @@ static inline void get_inline_info(struct f2fs_inode_info *fi,
> set_inode_flag(fi, FI_INLINE_DENTRY);
> if (ri->i_inline & F2FS_DATA_EXIST)
> set_inode_flag(fi, FI_DATA_EXIST);
> + if (ri->i_inline & F2FS_FAST_SYMLINK)
> + set_inode_flag(fi, FI_FAST_SYMLINK);
> }
>
> static inline void set_raw_inline(struct f2fs_inode_info *fi,
> @@ -1277,6 +1280,8 @@ static inline void set_raw_inline(struct f2fs_inode_info *fi,
> ri->i_inline |= F2FS_INLINE_DENTRY;
> if (is_inode_flag_set(fi, FI_DATA_EXIST))
> ri->i_inline |= F2FS_DATA_EXIST;
> + if (is_inode_flag_set(fi, FI_FAST_SYMLINK))
> + ri->i_inline |= F2FS_FAST_SYMLINK;
> }
>
> static inline int f2fs_has_inline_xattr(struct inode *inode)
> @@ -1370,6 +1375,15 @@ static inline void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi)
> sbi->sb->s_flags |= MS_RDONLY;
> }
>
> +/*
> + * Test whether an inode is a fast symlink.
> + */
> +static inline int f2fs_inode_is_fast_symlink(struct inode *inode)
> +{
> + return (S_ISLNK(inode->i_mode) &&
> + is_inode_flag_set(F2FS_I(inode), FI_FAST_SYMLINK));
> +}
> +
> #define get_inode_mode(i) \
> ((is_inode_flag_set(F2FS_I(i), FI_ACL_MODE)) ? \
> (F2FS_I(i)->i_acl_mode) : ((i)->i_mode))
> @@ -1746,6 +1760,7 @@ extern const struct address_space_operations f2fs_node_aops;
> extern const struct address_space_operations f2fs_meta_aops;
> extern const struct inode_operations f2fs_dir_inode_operations;
> extern const struct inode_operations f2fs_symlink_inode_operations;
> +extern const struct inode_operations f2fs_fast_symlink_inode_operations;
> extern const struct inode_operations f2fs_special_inode_operations;
> extern struct kmem_cache *inode_entry_slab;
>
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index f1341c7..05a3d4f 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -546,6 +546,8 @@ void f2fs_truncate(struct inode *inode)
> if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
> S_ISLNK(inode->i_mode)))
> return;
> + if (f2fs_inode_is_fast_symlink(inode))
> + return;
>
> trace_f2fs_truncate(inode);
>
> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> index b508744..ec9ad22 100644
> --- a/fs/f2fs/inode.c
> +++ b/fs/f2fs/inode.c
> @@ -13,6 +13,7 @@
> #include <linux/buffer_head.h>
> #include <linux/writeback.h>
> #include <linux/bitops.h>
> +#include <linux/namei.h>
>
> #include "f2fs.h"
> #include "node.h"
> @@ -188,8 +189,12 @@ make_now:
> inode->i_mapping->a_ops = &f2fs_dblock_aops;
> mapping_set_gfp_mask(inode->i_mapping, GFP_F2FS_HIGH_ZERO);
> } else if (S_ISLNK(inode->i_mode)) {
> - inode->i_op = &f2fs_symlink_inode_operations;
> - inode->i_mapping->a_ops = &f2fs_dblock_aops;
> + if (f2fs_inode_is_fast_symlink(inode))
> + inode->i_op = &f2fs_fast_symlink_inode_operations;
> + else {
> + inode->i_op = &f2fs_symlink_inode_operations;
> + inode->i_mapping->a_ops = &f2fs_dblock_aops;
> + }
> } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
> S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
> inode->i_op = &f2fs_special_inode_operations;
> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
> index 1e2ae21..0619909 100644
> --- a/fs/f2fs/namei.c
> +++ b/fs/f2fs/namei.c
> @@ -14,6 +14,7 @@
> #include <linux/sched.h>
> #include <linux/ctype.h>
> #include <linux/dcache.h>
> +#include <linux/namei.h>
>
> #include "f2fs.h"
> #include "node.h"
> @@ -247,6 +248,21 @@ fail:
> return err;
> }
>
> +static void *f2fs_follow_link(struct dentry *dentry, struct nameidata *nd)
> +{
> + struct page *node_page;
> +
> + node_page = get_node_page(F2FS_I_SB(dentry->d_inode),
> + dentry->d_inode->i_ino);
> + if (IS_ERR(node_page)) {
> + nd_set_link(nd, NULL);
> + return NULL;
> + }
> + nd_set_link(nd, (char *)(F2FS_INODE(node_page)->i_addr));
> + f2fs_put_page(node_page, 1);
> + return NULL;
> +}
> +
> static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
> const char *symname)
> {
> @@ -261,16 +277,31 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
> if (IS_ERR(inode))
> return PTR_ERR(inode);
>
> - inode->i_op = &f2fs_symlink_inode_operations;
> - inode->i_mapping->a_ops = &f2fs_dblock_aops;
> -
> f2fs_lock_op(sbi);
> err = f2fs_add_link(dentry, inode);
> if (err)
> goto out;
> f2fs_unlock_op(sbi);
>
> - 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?
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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