f2fs: introduce fi->i_sem to protect fi's info

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@samsung.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index e755ee57e042..a9474cd4e0db 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;
 }