Commit 5f3481e9 authored Sep 05, 2009 by Christoph Hellwig Committed by Theodore Ts'o Sep 05, 2009

ext4: fix cache flush in ext4_sync_file



We need to flush the write cache unconditionally in ->fsync, otherwise
writes into already allocated blocks can get lost.  Writes into fully
allocated files are very common when using disk images for
virtualization, and without this fix can easily lose data after
an fdatasync, which is the typical implementation for a cache flush on
the virtual drive.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

parent d0646f7b

fs/ext4/fsync.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -92,9 +92,9 @@ int ext4_sync_file(struct file file, struct dentry dentry, int datasync)
		.nr_to_write = 0, /* sys_fsync did this */
		};
		ret = sync_inode(inode, &wbc);
		if (journal && (journal->j_flags & JBD2_BARRIER))
		blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
		}
		out:
		if (journal && (journal->j_flags & JBD2_BARRIER))
		blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
		return ret;
		}

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