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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'o9bffad12009-06-17 11:48:11 -040031
Christoph Hellwig3dcf5452008-04-29 18:13:32 -040032#include "ext4.h"
33#include "ext4_jbd2.h"
Dave Kleikampac27a0e2006-10-11 01:20:50 -070034
Theodore Ts'o9bffad12009-06-17 11:48:11 -040035#include <trace/events/ext4.h>
36
Dave Kleikampac27a0e2006-10-11 01:20:50 -070037/*
Mingming Cao617ba132006-10-11 01:20:53 -070038 * akpm: A new design for ext4_sync_file().
Dave Kleikampac27a0e2006-10-11 01:20:50 -070039 *
40 * This is only called from sys_fsync(), sys_fdatasync() and sys_msync().
41 * There cannot be a transaction open by this task.
42 * Another task could have dirtied this inode. Its data can be in any
43 * state in the journalling system.
44 *
45 * What we do is just kick off a commit and wait on it. This will snapshot the
46 * inode to disk.
Mingming Cao8d5d02e2009-09-28 15:48:29 -040047 *
48 * i_mutex lock is held when entering and exiting this function
Dave Kleikampac27a0e2006-10-11 01:20:50 -070049 */
50
Theodore Ts'oaf5bc922008-09-08 22:25:24 -040051int ext4_sync_file(struct file *file, struct dentry *dentry, int datasync)
Dave Kleikampac27a0e2006-10-11 01:20:50 -070052{
53 struct inode *inode = dentry->d_inode;
Eric Sandeend755fb32008-07-11 19:27:31 -040054 journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
Theodore Ts'ofe188c02009-09-12 13:41:55 -040055 int err, ret = 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -070056
Aneesh Kumar K.Vac398492007-10-16 18:38:25 -040057 J_ASSERT(ext4_journal_current_handle() == NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070058
Theodore Ts'o9bffad12009-06-17 11:48:11 -040059 trace_ext4_sync_file(file, dentry, datasync);
Theodore Ts'oede86cc2008-10-05 20:50:06 -040060
Mingming Cao8d5d02e2009-09-28 15:48:29 -040061 ret = flush_aio_dio_completed_IO(inode);
62 if (ret < 0)
63 goto out;
Dave Kleikampac27a0e2006-10-11 01:20:50 -070064 /*
65 * data=writeback:
66 * The caller's filemap_fdatawrite()/wait will sync the data.
67 * sync_inode() will sync the metadata
68 *
69 * data=ordered:
70 * The caller's filemap_fdatawrite() will write the data and
71 * sync_inode() will write the inode if it is dirty. Then the caller's
72 * filemap_fdatawait() will wait on the pages.
73 *
74 * data=journal:
75 * filemap_fdatawrite won't do anything (the buffers are clean).
Mingming Cao617ba132006-10-11 01:20:53 -070076 * ext4_force_commit will write the file data into the journal and
Dave Kleikampac27a0e2006-10-11 01:20:50 -070077 * will wait on that.
78 * filemap_fdatawait() will encounter a ton of newly-dirtied pages
79 * (they were dirtied by commit). But that's OK - the blocks are
80 * safe in-journal, which is all fsync() needs to ensure.
81 */
Mingming Cao617ba132006-10-11 01:20:53 -070082 if (ext4_should_journal_data(inode)) {
83 ret = ext4_force_commit(inode->i_sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070084 goto out;
85 }
86
Theodore Ts'ofe188c02009-09-12 13:41:55 -040087 if (!journal)
88 ret = sync_mapping_buffers(inode->i_mapping);
89
Hisashi Hifumi53c550e2008-04-17 10:38:59 -040090 if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
91 goto out;
92
Dave Kleikampac27a0e2006-10-11 01:20:50 -070093 /*
94 * The VFS has written the file data. If the inode is unaltered
95 * then we need not start a commit.
96 */
97 if (inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC)) {
98 struct writeback_control wbc = {
99 .sync_mode = WB_SYNC_ALL,
100 .nr_to_write = 0, /* sys_fsync did this */
101 };
Theodore Ts'ofe188c02009-09-12 13:41:55 -0400102 err = sync_inode(inode, &wbc);
103 if (ret == 0)
104 ret = err;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700105 }
106out:
Christoph Hellwig5f3481e2009-09-05 21:42:42 -0400107 if (journal && (journal->j_flags & JBD2_BARRIER))
108 blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700109 return ret;
110}