[PATCH 1/3] f2fs: introduce fi->i_sem to protect fi's info

From: Jaegeuk Kim
Date: Thu Mar 20 2014 - 22:04:14 EST


This patch introduces fi->i_sem to protect fi's info that includes xattr_ver,
pino, i_nlink.
This enables to remove i_mutex during f2fs_sync_file, resulting in performance
improvement when a number of fsync calls are triggered from many concurrent
threads.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx>
---
fs/f2fs/dir.c | 6 ++++++
fs/f2fs/f2fs.h | 1 +
fs/f2fs/file.c | 14 ++++++++++----
fs/f2fs/namei.c | 7 +++++++
fs/f2fs/super.c | 1 +
fs/f2fs/xattr.c | 3 +++
6 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 7c9b17c..972fd0e 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -493,6 +493,7 @@ start:
add_dentry:
f2fs_wait_on_page_writeback(dentry_page, DATA);

+ down_write(&F2FS_I(inode)->i_sem);
page = init_inode_metadata(inode, dir, name);
if (IS_ERR(page)) {
err = PTR_ERR(page);
@@ -515,6 +516,8 @@ add_dentry:

update_parent_metadata(dir, inode, current_depth);
fail:
+ up_write(&F2FS_I(inode)->i_sem);
+
if (is_inode_flag_set(F2FS_I(dir), FI_UPDATE_DIR)) {
update_inode_page(dir);
clear_inode_flag(F2FS_I(dir), FI_UPDATE_DIR);
@@ -559,6 +562,8 @@ void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
if (inode) {
struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);

+ down_write(&F2FS_I(inode)->i_sem);
+
if (S_ISDIR(inode->i_mode)) {
drop_nlink(dir);
update_inode_page(dir);
@@ -569,6 +574,7 @@ void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
drop_nlink(inode);
i_size_write(inode, 0);
}
+ up_write(&F2FS_I(inode)->i_sem);
update_inode_page(inode);

if (inode->i_nlink == 0)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 05c6524..469779a 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -210,6 +210,7 @@ struct f2fs_inode_info {

/* Use below internally in f2fs*/
unsigned long flags; /* use to pass per-file flags */
+ struct rw_semaphore i_sem; /* protect fi info */
atomic_t dirty_dents; /* # of dirty dentry pages */
f2fs_hash_t chash; /* hash value of given file name */
unsigned int clevel; /* maximum level of given file name */
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index e755ee5..a9474cd 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -111,6 +111,7 @@ static int get_parent_ino(struct inode *inode, nid_t *pino)
int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
{
struct inode *inode = file->f_mapping->host;
+ struct f2fs_inode_info *fi = F2FS_I(inode);
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
int ret = 0;
bool need_cp = false;
@@ -133,7 +134,7 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
/* guarantee free sections for fsync */
f2fs_balance_fs(sbi);

- mutex_lock(&inode->i_mutex);
+ down_read(&fi->i_sem);

/*
* Both of fdatasync() and fsync() are able to be recovered from
@@ -150,21 +151,27 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
else if (F2FS_I(inode)->xattr_ver == cur_cp_version(F2FS_CKPT(sbi)))
need_cp = true;

+ up_read(&fi->i_sem);
+
if (need_cp) {
nid_t pino;

- F2FS_I(inode)->xattr_ver = 0;
-
/* all the dirty node pages should be flushed for POR */
ret = f2fs_sync_fs(inode->i_sb, 1);
+
+ down_write(&fi->i_sem);
+ F2FS_I(inode)->xattr_ver = 0;
if (file_wrong_pino(inode) && inode->i_nlink == 1 &&
get_parent_ino(inode, &pino)) {
F2FS_I(inode)->i_pino = pino;
file_got_pino(inode);
+ up_write(&fi->i_sem);
mark_inode_dirty_sync(inode);
ret = f2fs_write_inode(inode, NULL);
if (ret)
goto out;
+ } else {
+ up_write(&fi->i_sem);
}
} else {
/* if there is no written node page, write its inode page */
@@ -180,7 +187,6 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
ret = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
}
out:
- mutex_unlock(&inode->i_mutex);
trace_f2fs_sync_file_exit(inode, need_cp, datasync, ret);
return ret;
}
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 397d459..0cea874 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -424,12 +424,17 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
}

f2fs_set_link(new_dir, new_entry, new_page, old_inode);
+ down_write(&F2FS_I(old_inode)->i_sem);
F2FS_I(old_inode)->i_pino = new_dir->i_ino;
+ up_write(&F2FS_I(old_inode)->i_sem);

new_inode->i_ctime = CURRENT_TIME;
+ down_write(&F2FS_I(new_inode)->i_sem);
if (old_dir_entry)
drop_nlink(new_inode);
drop_nlink(new_inode);
+ up_write(&F2FS_I(new_inode)->i_sem);
+
mark_inode_dirty(new_inode);

if (!new_inode->i_nlink)
@@ -459,7 +464,9 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
if (old_dir != new_dir) {
f2fs_set_link(old_inode, old_dir_entry,
old_dir_page, new_dir);
+ down_write(&F2FS_I(old_inode)->i_sem);
F2FS_I(old_inode)->i_pino = new_dir->i_ino;
+ up_write(&F2FS_I(old_inode)->i_sem);
update_inode_page(old_inode);
} else {
kunmap(old_dir_page);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 34c47b2..89ea046 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -360,6 +360,7 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb)
fi->i_current_depth = 1;
fi->i_advise = 0;
rwlock_init(&fi->ext.ext_lock);
+ init_rwsem(&fi->i_sem);

set_inode_flag(fi, FI_NEW_INODE);

diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index 89d0422..8419130 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -590,7 +590,10 @@ int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
f2fs_balance_fs(sbi);

f2fs_lock_op(sbi);
+ /* protect xattr_ver */
+ down_write(&F2FS_I(inode)->i_sem);
err = __f2fs_setxattr(inode, name_index, name, value, value_len, ipage);
+ up_write(&F2FS_I(inode)->i_sem);
f2fs_unlock_op(sbi);

return err;
--
1.8.4.474.g128a96c

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