fsync.c 2.8 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10
/*
 *  linux/fs/ext3/fsync.c
 *
 *  Copyright (C) 1993  Stephen Tweedie (sct@redhat.com)
 *  from
 *  Copyright (C) 1992  Remy Card (card@masi.ibp.fr)
 *                      Laboratoire MASI - Institut Blaise Pascal
 *                      Universite Pierre et Marie Curie (Paris VI)
 *  from
 *  linux/fs/minix/truncate.c   Copyright (C) 1991, 1992  Linus Torvalds
11
 *
L
Linus Torvalds 已提交
12 13 14 15
 *  ext3fs fsync primitive
 *
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller (davem@caip.rutgers.edu), 1995
16
 *
L
Linus Torvalds 已提交
17
 *  Removed unnecessary code duplication for little endian machines
18
 *  and excessive __inline__s.
L
Linus Torvalds 已提交
19 20 21 22 23 24 25
 *        Andi Kleen, 1997
 *
 * Major simplications and cleanup - we only need to do the metadata, because
 * we can depend on generic_block_fdatasync() to sync the data blocks.
 */

#include <linux/time.h>
26
#include <linux/blkdev.h>
L
Linus Torvalds 已提交
27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/writeback.h>
#include <linux/jbd.h>
#include <linux/ext3_fs.h>
#include <linux/ext3_jbd.h>

/*
 * akpm: A new design for ext3_sync_file().
 *
 * This is only called from sys_fsync(), sys_fdatasync() and sys_msync().
 * There cannot be a transaction open by this task.
 * Another task could have dirtied this inode.  Its data can be in any
 * state in the journalling system.
 *
 * What we do is just kick off a commit and wait on it.  This will snapshot the
 * inode to disk.
 */

int ext3_sync_file(struct file * file, struct dentry *dentry, int datasync)
{
	struct inode *inode = dentry->d_inode;
49 50
	struct ext3_inode_info *ei = EXT3_I(inode);
	journal_t *journal = EXT3_SB(inode->i_sb)->s_journal;
L
Linus Torvalds 已提交
51
	int ret = 0;
52 53 54 55
	tid_t commit_tid;

	if (inode->i_sb->s_flags & MS_RDONLY)
		return 0;
L
Linus Torvalds 已提交
56

57
	J_ASSERT(ext3_journal_current_handle() == NULL);
L
Linus Torvalds 已提交
58 59

	/*
60
	 * data=writeback,ordered:
L
Linus Torvalds 已提交
61
	 *  The caller's filemap_fdatawrite()/wait will sync the data.
62 63
	 *  Metadata is in the journal, we wait for a proper transaction
	 *  to commit here.
L
Linus Torvalds 已提交
64 65 66 67 68 69 70 71 72 73 74 75 76 77
	 *
	 * data=journal:
	 *  filemap_fdatawrite won't do anything (the buffers are clean).
	 *  ext3_force_commit will write the file data into the journal and
	 *  will wait on that.
	 *  filemap_fdatawait() will encounter a ton of newly-dirtied pages
	 *  (they were dirtied by commit).  But that's OK - the blocks are
	 *  safe in-journal, which is all fsync() needs to ensure.
	 */
	if (ext3_should_journal_data(inode)) {
		ret = ext3_force_commit(inode->i_sb);
		goto out;
	}

78 79 80 81
	if (datasync)
		commit_tid = atomic_read(&ei->i_datasync_tid);
	else
		commit_tid = atomic_read(&ei->i_sync_tid);
82

83 84
	if (log_start_commit(journal, commit_tid)) {
		log_wait_commit(journal, commit_tid);
85
		goto out;
L
Linus Torvalds 已提交
86
	}
87

88 89 90 91 92 93 94
	/*
	 * In case we didn't commit a transaction, we have to flush
	 * disk caches manually so that data really is on persistent
	 * storage
	 */
	if (test_opt(inode->i_sb, BARRIER))
		blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
L
Linus Torvalds 已提交
95 96 97
out:
	return ret;
}