Release 4.15 fs/ext4/fsync.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  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/blkdev.h>

#include "ext4.h"
#include "ext4_jbd2.h"

#include <trace/events/ext4.h>

/*
 * If we're not journaling and this is a just-created file, we have to
 * sync our parent directory (if it was freshly created) since
 * otherwise it will only be written by writeback, leaving a huge
 * window during which a crash may lose the file.  This may apply for
 * the parent directory's parent as well, and so on recursively, if
 * they are also freshly created.
 */


static int ext4_sync_parent(struct inode *inode)
{
	struct dentry *dentry = NULL;
	struct inode *next;
	int ret = 0;

	if (!ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY))
		return 0;
	inode = igrab(inode);
	while (ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY)) {
		ext4_clear_inode_state(inode, EXT4_STATE_NEWENTRY);
		dentry = d_find_any_alias(inode);
		if (!dentry)
			break;
		next = igrab(d_inode(dentry->d_parent));
		dput(dentry);
		if (!next)
			break;
		iput(inode);
		inode = next;
		/*
                 * The directory inode may have gone through rmdir by now. But
                 * the inode itself and its blocks are still allocated (we hold
                 * a reference to the inode so it didn't go through
                 * ext4_evict_inode()) and so we are safe to flush metadata
                 * blocks and the inode.
                 */
		ret = sync_mapping_buffers(inode->i_mapping);
		if (ret)
			break;
		ret = sync_inode_metadata(inode, 1);
		if (ret)
			break;
	}
	iput(inode);
	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Theodore Y. Ts'o
57
38.51%
1
14.29%
Frank Mayhar
56
37.84%
1
14.29%
Curt Wohlgemuth
28
18.92%
1
14.29%
David Howells
3
2.03%
1
14.29%
Guo Chao
2
1.35%
1
14.29%
Jan Kara
1
0.68%
1
14.29%
Al Viro
1
0.68%
1
14.29%
Total
148
100.00%
7
100.00%

/*
 * 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, loff_t start, loff_t end, int datasync)
{
	struct inode *inode = file->f_mapping->host;
	struct ext4_inode_info *ei = EXT4_I(inode);
	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
	int ret = 0, err;
	tid_t commit_tid;
	bool needs_barrier = false;

	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
		return -EIO;

	J_ASSERT(ext4_journal_current_handle() == NULL);

	trace_ext4_sync_file_enter(file, datasync);

	if (sb_rdonly(inode->i_sb)) {
		/* Make sure that we read updated s_mount_flags value */
		smp_rmb();
		if (EXT4_SB(inode->i_sb)->s_mount_flags & EXT4_MF_FS_ABORTED)
			ret = -EROFS;
		goto out;
	}

	if (!journal) {
		ret = __generic_file_fsync(file, start, end, datasync);
		if (!ret)
			ret = ext4_sync_parent(inode);
		if (test_opt(inode->i_sb, BARRIER))
			goto issue_flush;
		goto out;
	}

	ret = file_write_and_wait_range(file, start, end);
	if (ret)
		return ret;
	/*
         * data=writeback,ordered:
         *  The caller's filemap_fdatawrite()/wait will sync the data.
         *  Metadata is in the journal, we wait for proper transaction to
         *  commit here.
         *
         * 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;
	}

	commit_tid = datasync ? ei->i_datasync_tid : ei->i_sync_tid;
	if (journal->j_flags & JBD2_BARRIER &&
	    !jbd2_trans_will_send_data_barrier(journal, commit_tid))
		needs_barrier = true;
	ret = jbd2_complete_transaction(journal, commit_tid);
	if (needs_barrier) {
	issue_flush:
		err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
		if (!ret)
			ret = err;
	}
out:
	trace_ext4_sync_file_exit(inode, ret);
	return ret;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Jan Kara
88
28.21%
4
15.38%
Theodore Y. Ts'o
61
19.55%
7
26.92%
Dave Kleikamp
47
15.06%
1
3.85%
Dmitriy Monakhov
28
8.97%
3
11.54%
Eric Sandeen
27
8.65%
1
3.85%
Jiaying Zhang
20
6.41%
1
3.85%
Frank Mayhar
15
4.81%
1
3.85%
Josef Bacik
8
2.56%
1
3.85%
Christoph Hellwig
4
1.28%
1
3.85%
Mingming Cao
4
1.28%
1
3.85%
David Howells
3
0.96%
1
3.85%
Curt Wohlgemuth
2
0.64%
1
3.85%
Hisashi Hifumi
2
0.64%
1
3.85%
Jeff Layton
2
0.64%
1
3.85%
Aneesh Kumar K.V
1
0.32%
1
3.85%
Total
312
100.00%
26
100.00%

Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Theodore Y. Ts'o
123
25.20%
8
24.24%
Jan Kara
89
18.24%
5
15.15%
Frank Mayhar
72
14.75%
1
3.03%
Dave Kleikamp
63
12.91%
1
3.03%
Eric Sandeen
30
6.15%
1
3.03%
Curt Wohlgemuth
30
6.15%
1
3.03%
Dmitriy Monakhov
28
5.74%
3
9.09%
Jiaying Zhang
20
4.10%
1
3.03%
Josef Bacik
8
1.64%
1
3.03%
David Howells
6
1.23%
2
6.06%
Mingming Cao
5
1.02%
1
3.03%
Christoph Hellwig
4
0.82%
1
3.03%
Hisashi Hifumi
2
0.41%
1
3.03%
Jeff Layton
2
0.41%
1
3.03%
Guo Chao
2
0.41%
1
3.03%
Andrew Lutomirski
1
0.20%
1
3.03%
Al Viro
1
0.20%
1
3.03%
Greg Kroah-Hartman
1
0.20%
1
3.03%
Aneesh Kumar K.V
1
0.20%
1
3.03%
Total
488
100.00%
33
100.00%
Directory: fs/ext4

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