[PATCH 2/5] ext3: call blkdev_issue_flush on fsync()

Fernando Luis Vázquez Cao
2009-03-30T01:41:12Z

To ensure that bits are truly on-disk after an fsync or fdatasync, we
should force a disk flush explicitly when there is dirty data/metadata
and the journal didn't emit a write barrier (either because metadata is
not being synched or barriers are disabled).

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
---

diff -urNp linux-2.6.29-orig/fs/ext3/fsync.c linux-2.6.29/fs/ext3/fsync.c
--- linux-2.6.29-orig/fs/ext3/fsync.c 2009-03-24 08:12:14.000000000 +0900
+++ linux-2.6.29/fs/ext3/fsync.c 2009-03-28 20:45:40.000000000 +0900
@@ -45,6 +45,8 @@
int ext3_sync_file(struct file * file, struct dentry *dentry, int datasync)
{
struct inode *inode = dentry->d_inode;
+ journal_t *journal = EXT3_SB(inode->i_sb)->s_journal;
+ unsigned long i_state = inode->i_state;
int ret = 0;

J_ASSERT(ext3_journal_current_handle() == NULL);
@@ -69,23 +71,30 @@ int ext3_sync_file(struct file * file, s
*/
if (ext3_should_journal_data(inode)) {
ret = ext3_force_commit(inode->i_sb);
- goto out;
+ if (!(journal->j_flags & JFS_BARRIER))
+ block_flush_device(inode->i_sb);
+ return ret;
}

- if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
- goto out;
+ if (datasync && !(i_state & I_DIRTY_DATASYNC)) {
+ if (i_state & I_DIRTY_PAGES)
+ block_flush_device(inode->i_sb);
+ return ret;
+ }

/*
* 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)) {
+ if (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);
+ if (journal && !(journal->j_flags & JFS_BARRIER))
+ block_flush_device(inode->i_sb);
}
-out:
+
return ret;
}