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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>
Eric Sandeend755fb32008-07-11 19:27:31 -040030#include <linux/blkdev.h>
Theodore Ts'oede86cc2008-10-05 20:50:06 -040031#include <linux/marker.h>
Christoph Hellwig3dcf5452008-04-29 18:13:32 -040032#include "ext4.h"
33#include "ext4_jbd2.h"
Dave Kleikampac27a0e2006-10-11 01:20:50 -070034
35/*
Mingming Cao617ba132006-10-11 01:20:53 -070036 * akpm: A new design for ext4_sync_file().
Dave Kleikampac27a0e2006-10-11 01:20:50 -070037 *
38 * This is only called from sys_fsync(), sys_fdatasync() and sys_msync().
39 * There cannot be a transaction open by this task.
40 * Another task could have dirtied this inode. Its data can be in any
41 * state in the journalling system.
42 *
43 * What we do is just kick off a commit and wait on it. This will snapshot the
44 * inode to disk.
45 */
46
Theodore Ts'oaf5bc922008-09-08 22:25:24 -040047int ext4_sync_file(struct file *file, struct dentry *dentry, int datasync)
Dave Kleikampac27a0e2006-10-11 01:20:50 -070048{
49 struct inode *inode = dentry->d_inode;
Eric Sandeend755fb32008-07-11 19:27:31 -040050 journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
Dave Kleikampac27a0e2006-10-11 01:20:50 -070051 int ret = 0;
52
Aneesh Kumar K.Vac398492007-10-16 18:38:25 -040053 J_ASSERT(ext4_journal_current_handle() == NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070054
Theodore Ts'oede86cc2008-10-05 20:50:06 -040055 trace_mark(ext4_sync_file, "dev %s datasync %d ino %ld parent %ld",
56 inode->i_sb->s_id, datasync, inode->i_ino,
57 dentry->d_parent->d_inode->i_ino);
58
Dave Kleikampac27a0e2006-10-11 01:20:50 -070059 /*
60 * data=writeback:
61 * The caller's filemap_fdatawrite()/wait will sync the data.
62 * sync_inode() will sync the metadata
63 *
64 * data=ordered:
65 * The caller's filemap_fdatawrite() will write the data and
66 * sync_inode() will write the inode if it is dirty. Then the caller's
67 * filemap_fdatawait() will wait on the pages.
68 *
69 * data=journal:
70 * filemap_fdatawrite won't do anything (the buffers are clean).
Mingming Cao617ba132006-10-11 01:20:53 -070071 * ext4_force_commit will write the file data into the journal and
Dave Kleikampac27a0e2006-10-11 01:20:50 -070072 * will wait on that.
73 * filemap_fdatawait() will encounter a ton of newly-dirtied pages
74 * (they were dirtied by commit). But that's OK - the blocks are
75 * safe in-journal, which is all fsync() needs to ensure.
76 */
Mingming Cao617ba132006-10-11 01:20:53 -070077 if (ext4_should_journal_data(inode)) {
78 ret = ext4_force_commit(inode->i_sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070079 goto out;
80 }
81
Hisashi Hifumi53c550e2008-04-17 10:38:59 -040082 if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
83 goto out;
84
Dave Kleikampac27a0e2006-10-11 01:20:50 -070085 /*
86 * The VFS has written the file data. If the inode is unaltered
87 * then we need not start a commit.
88 */
89 if (inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC)) {
90 struct writeback_control wbc = {
91 .sync_mode = WB_SYNC_ALL,
92 .nr_to_write = 0, /* sys_fsync did this */
93 };
94 ret = sync_inode(inode, &wbc);
Eric Sandeend755fb32008-07-11 19:27:31 -040095 if (journal && (journal->j_flags & JBD2_BARRIER))
96 blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070097 }
98out:
99 return ret;
100}