[PATCH] f2fs: add fast symlink support

From: Wanpeng Li
Date: Thu Mar 12 2015 - 02:53:57 EST

Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
---
fs/f2fs/f2fs.h | 15 ++++++++++++++
fs/f2fs/file.c | 2 ++
fs/f2fs/inode.c | 9 +++++++--
fs/f2fs/namei.c | 53 +++++++++++++++++++++++++++++++++++++++++++++----
include/linux/f2fs_fs.h | 2 ++
5 files changed, 75 insertions(+), 6 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);
+ 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/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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