mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-18 17:54:13 +08:00
89 lines
2.6 KiB
C
89 lines
2.6 KiB
C
/*
|
|
* linux/fs/ext4/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
|
|
*
|
|
* ext4fs fsync primitive
|
|
*
|
|
* Big-endian to little-endian byte-swapping/bitmaps by
|
|
* David S. Miller (davem@caip.rutgers.edu), 1995
|
|
*
|
|
* Removed unnecessary code duplication for little endian machines
|
|
* and excessive __inline__s.
|
|
* 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>
|
|
#include <linux/fs.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/writeback.h>
|
|
#include <linux/jbd2.h>
|
|
#include <linux/ext4_fs.h>
|
|
#include <linux/ext4_jbd2.h>
|
|
|
|
/*
|
|
* akpm: A new design for ext4_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 ext4_sync_file(struct file * file, struct dentry *dentry, int datasync)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
int ret = 0;
|
|
|
|
J_ASSERT(ext4_journal_current_handle() == NULL);
|
|
|
|
/*
|
|
* data=writeback:
|
|
* The caller's filemap_fdatawrite()/wait will sync the data.
|
|
* sync_inode() will sync the metadata
|
|
*
|
|
* data=ordered:
|
|
* The caller's filemap_fdatawrite() will write the data and
|
|
* sync_inode() will write the inode if it is dirty. Then the caller's
|
|
* filemap_fdatawait() will wait on the pages.
|
|
*
|
|
* data=journal:
|
|
* filemap_fdatawrite won't do anything (the buffers are clean).
|
|
* ext4_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 (ext4_should_journal_data(inode)) {
|
|
ret = ext4_force_commit(inode->i_sb);
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* The VFS has written the file data. If the inode is unaltered
|
|
* then we need not start a commit.
|
|
*/
|
|
if (inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC)) {
|
|
struct writeback_control wbc = {
|
|
.sync_mode = WB_SYNC_ALL,
|
|
.nr_to_write = 0, /* sys_fsync did this */
|
|
};
|
|
ret = sync_inode(inode, &wbc);
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|