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Dave Kleikampac27a0e2006-10-11 01:20:50 -07001/*
Mingming Cao617ba132006-10-11 01:20:53 -07002 * linux/fs/ext4/fsync.c
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003 *
4 * Copyright (C) 1993 Stephen Tweedie (sct@redhat.com)
5 * from
6 * Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
7 * Laboratoire MASI - Institut Blaise Pascal
8 * Universite Pierre et Marie Curie (Paris VI)
9 * from
10 * linux/fs/minix/truncate.c Copyright (C) 1991, 1992 Linus Torvalds
11 *
Mingming Cao617ba132006-10-11 01:20:53 -070012 * ext4fs fsync primitive
Dave Kleikampac27a0e2006-10-11 01:20:50 -070013 *
14 * Big-endian to little-endian byte-swapping/bitmaps by
15 * David S. Miller (davem@caip.rutgers.edu), 1995
16 *
17 * Removed unnecessary code duplication for little endian machines
18 * and excessive __inline__s.
19 * Andi Kleen, 1997
20 *
21 * Major simplications and cleanup - we only need to do the metadata, because
22 * we can depend on generic_block_fdatasync() to sync the data blocks.
23 */
24
25#include <linux/time.h>
26#include <linux/fs.h>
27#include <linux/sched.h>
28#include <linux/writeback.h>
Mingming Caodab291a2006-10-11 01:21:01 -070029#include <linux/jbd2.h>
Mingming Cao617ba132006-10-11 01:20:53 -070030#include <linux/ext4_fs.h>
Mingming Caodab291a2006-10-11 01:21:01 -070031#include <linux/ext4_jbd2.h>
Dave Kleikampac27a0e2006-10-11 01:20:50 -070032
33/*
Mingming Cao617ba132006-10-11 01:20:53 -070034 * akpm: A new design for ext4_sync_file().
Dave Kleikampac27a0e2006-10-11 01:20:50 -070035 *
36 * This is only called from sys_fsync(), sys_fdatasync() and sys_msync().
37 * There cannot be a transaction open by this task.
38 * Another task could have dirtied this inode. Its data can be in any
39 * state in the journalling system.
40 *
41 * What we do is just kick off a commit and wait on it. This will snapshot the
42 * inode to disk.
43 */
44
Mingming Cao617ba132006-10-11 01:20:53 -070045int ext4_sync_file(struct file * file, struct dentry *dentry, int datasync)
Dave Kleikampac27a0e2006-10-11 01:20:50 -070046{
47 struct inode *inode = dentry->d_inode;
48 int ret = 0;
49
Mingming Cao617ba132006-10-11 01:20:53 -070050 J_ASSERT(ext4_journal_current_handle() == 0);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070051
52 /*
53 * data=writeback:
54 * The caller's filemap_fdatawrite()/wait will sync the data.
55 * sync_inode() will sync the metadata
56 *
57 * data=ordered:
58 * The caller's filemap_fdatawrite() will write the data and
59 * sync_inode() will write the inode if it is dirty. Then the caller's
60 * filemap_fdatawait() will wait on the pages.
61 *
62 * data=journal:
63 * filemap_fdatawrite won't do anything (the buffers are clean).
Mingming Cao617ba132006-10-11 01:20:53 -070064 * ext4_force_commit will write the file data into the journal and
Dave Kleikampac27a0e2006-10-11 01:20:50 -070065 * will wait on that.
66 * filemap_fdatawait() will encounter a ton of newly-dirtied pages
67 * (they were dirtied by commit). But that's OK - the blocks are
68 * safe in-journal, which is all fsync() needs to ensure.
69 */
Mingming Cao617ba132006-10-11 01:20:53 -070070 if (ext4_should_journal_data(inode)) {
71 ret = ext4_force_commit(inode->i_sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070072 goto out;
73 }
74
75 /*
76 * The VFS has written the file data. If the inode is unaltered
77 * then we need not start a commit.
78 */
79 if (inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC)) {
80 struct writeback_control wbc = {
81 .sync_mode = WB_SYNC_ALL,
82 .nr_to_write = 0, /* sys_fsync did this */
83 };
84 ret = sync_inode(inode, &wbc);
85 }
86out:
87 return ret;
88}