ext4: sync the directory inode in ext4_sync_parent() (0893ed45) · Commits · 戴 / test

ext4 has taken the stance that, in the absence of a journal, when an fsync/fdatasync of an inode is done, the parent directory should be sync'ed if this inode entry is new. ext4_sync_parent(), which implements this, does indeed sync the dirent pages for parent directories, but it does not sync the directory *inode*. This patch fixes this. Also now return error status from ext4_sync_parent(). I tested this using a power fail test, which panics a machine running a file server getting requests from a client. Without this patch, on about every other test run, the server is missing many, many files that had been synced. With this patch, on > 6 runs, I see zero files being lost. Google-Bug-Id: 4179519 Signed-off-by:

Curt Wohlgemuth <curtw@google.com> Signed-off-by:

"Theodore Ts'o" <tytso@mit.edu>

fs/ext4/fsync.c

+14 −3

Original line number	Diff line number	Diff line
		@@ -125,9 +125,11 @@ extern int ext4_flush_completed_IO(struct inode *inode)
		* the parent directory's parent as well, and so on recursively, if
		* they are also freshly created.
		*/
		static void ext4_sync_parent(struct inode *inode)
		static int ext4_sync_parent(struct inode *inode)
		{
		struct writeback_control wbc;
		struct dentry *dentry = NULL;
		int ret = 0;

		while (inode && ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY)) {
		ext4_clear_inode_state(inode, EXT4_STATE_NEWENTRY);
		@@ -136,8 +138,17 @@ static void ext4_sync_parent(struct inode *inode)
		if (!dentry \|\| !dentry->d_parent \|\| !dentry->d_parent->d_inode)
		break;
		inode = dentry->d_parent->d_inode;
		sync_mapping_buffers(inode->i_mapping);
		ret = sync_mapping_buffers(inode->i_mapping);
		if (ret)
		break;
		memset(&wbc, 0, sizeof(wbc));
		wbc.sync_mode = WB_SYNC_ALL;
		wbc.nr_to_write = 0; /* only write out the inode */
		ret = sync_inode(inode, &wbc);
		if (ret)
		break;
		}
		return ret;
		}

		/*
		@@ -176,7 +187,7 @@ int ext4_sync_file(struct file *file, int datasync)
		if (!journal) {
		ret = generic_file_fsync(file, datasync);
		if (!ret && !list_empty(&inode->i_dentry))
		ext4_sync_parent(inode);
		ret = ext4_sync_parent(inode);
		goto out;
		}

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