fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlers

Btrfs needs to be able to control how filemap_write_and_wait_range() is called
in fsync to make it less of a painful operation, so push down taking i_mutex and
the calling of filemap_write_and_wait() down into the ->fsync() handlers.  Some
file systems can drop taking the i_mutex altogether it seems, like ext3 and
ocfs2.  For correctness sake I just pushed everything down in all cases to make
sure that we keep the current behavior the same for everybody, and then each
individual fs maintainer can make up their mind about what to do from there.
Thanks,

Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 11 insertions, 2 deletions

diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index d6857523336d..38184e360932 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -392,7 +392,8 @@ int hfsplus_cat_read_inode(struct inode *, struct hfs_find_data *);
 int hfsplus_cat_write_inode(struct inode *);
 struct inode *hfsplus_new_inode(struct super_block *, int);
 void hfsplus_delete_inode(struct inode *);
-int hfsplus_file_fsync(struct file *file, int datasync);
+int hfsplus_file_fsync(struct file *file, loff_t start, loff_t end,
+                       int datasync);
 
 /* ioctl.c */
 long hfsplus_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index 5b1cb98741cc..30486e01d003 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -308,13 +308,19 @@ static int hfsplus_setattr(struct dentry *dentry, struct iattr *attr)
         return 0;
 }
 
-int hfsplus_file_fsync(struct file *file, int datasync)
+int hfsplus_file_fsync(struct file *file, loff_t start, loff_t end,
+                       int datasync)
 {
         struct inode *inode = file->f_mapping->host;
         struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
         struct hfsplus_sb_info *sbi = HFSPLUS_SB(inode->i_sb);
         int error = 0, error2;
 
+        error = filemap_write_and_wait_range(inode->i_mapping, start, end);
+        if (error)
+                return error;
+        mutex_lock(&inode->i_mutex);
+
         /*
          * Sync inode metadata into the catalog and extent trees.
          */
@@ -342,6 +348,8 @@ int hfsplus_file_fsync(struct file *file, int datasync)
         if (!test_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags))
                 blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
 
+        mutex_unlock(&inode->i_mutex);
+
         return error;
 }