add a vfs_fsync helper

[safe/jmp/linux-2.6] / fs / sync.c

diff --git a/fs/sync.c b/fs/sync.c
index 2967562..0921d6d 100644 (file)
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -75,14 +75,39 @@ int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
        return ret;
 }
 
-long do_fsync(struct file *file, int datasync)
+/**
+ * vfs_fsync - perform a fsync or fdatasync on a file
+ * @file:              file to sync
+ * @dentry:            dentry of @file
+ * @data:              only perform a fdatasync operation
+ *
+ * Write back data and metadata for @file to disk.  If @datasync is
+ * set only metadata needed to access modified file data is written.
+ *
+ * In case this function is called from nfsd @file may be %NULL and
+ * only @dentry is set.  This can only happen when the filesystem
+ * implements the export_operations API.
+ */
+int vfs_fsync(struct file *file, struct dentry *dentry, int datasync)
 {
-       int ret;
-       int err;
-       struct address_space *mapping = file->f_mapping;
+       const struct file_operations *fop;
+       struct address_space *mapping;
+       int err, ret;
+
+       /*
+        * Get mapping and operations from the file in case we have
+        * as file, or get the default values for them in case we
+        * don't have a struct file available.  Damn nfsd..
+        */
+       if (file) {
+               mapping = file->f_mapping;
+               fop = file->f_op;
+       } else {
+               mapping = dentry->d_inode->i_mapping;
+               fop = dentry->d_inode->i_fop;
+       }
 
-       if (!file->f_op || !file->f_op->fsync) {
-               /* Why?  We can still call filemap_fdatawrite */
+       if (!fop || !fop->fsync) {
                ret = -EINVAL;
                goto out;
        }
@@ -94,7 +119,7 @@ long do_fsync(struct file *file, int datasync)
         * livelocks in fsync_buffers_list().
         */
        mutex_lock(&mapping->host->i_mutex);
-       err = file->f_op->fsync(file, file->f_path.dentry, datasync);
+       err = fop->fsync(file, dentry, datasync);
        if (!ret)
                ret = err;
        mutex_unlock(&mapping->host->i_mutex);
@@ -104,15 +129,16 @@ long do_fsync(struct file *file, int datasync)
 out:
        return ret;
 }
+EXPORT_SYMBOL(vfs_fsync);
 
-static long __do_fsync(unsigned int fd, int datasync)
+static int do_fsync(unsigned int fd, int datasync)
 {
        struct file *file;
        int ret = -EBADF;
 
        file = fget(fd);
        if (file) {
-               ret = do_fsync(file, datasync);
+               ret = vfs_fsync(file, file->f_path.dentry, datasync);
                fput(file);
        }
        return ret;
@@ -120,12 +146,12 @@ static long __do_fsync(unsigned int fd, int datasync)
 
 asmlinkage long sys_fsync(unsigned int fd)
 {
-       return __do_fsync(fd, 0);
+       return do_fsync(fd, 0);
 }
 
 asmlinkage long sys_fdatasync(unsigned int fd)
 {
-       return __do_fsync(fd, 1);
+       return do_fsync(fd, 1);
 }
 
 /*