Commit 495e8677 authored Nov 19, 2010 by Josef Bacik Committed by Chris Mason Nov 21, 2010

Btrfs: hold i_mutex when calling btrfs_log_dentry_safe

Since we walk up the path logging all of the parts of the inode's path, we need
to hold i_mutex to make sure that the inode is not renamed while we're logging
everything. btrfs_log_dentry_safe does dget_parent and all of that jazz, but we
may get unexpected results if the rename changes the inode's location while
we're higher up the path logging those dentries, so do this for safety reasons.
Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

parent 6a912213

fs/btrfs/file.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -1047,8 +1047,14 @@ out:

		if ((file->f_flags & O_DSYNC) \|\| IS_SYNC(inode)) {
		trans = btrfs_start_transaction(root, 0);
		if (IS_ERR(trans)) {
		num_written = PTR_ERR(trans);
		goto done;
		}
		mutex_lock(&inode->i_mutex);
		ret = btrfs_log_dentry_safe(trans, root,
		file->f_dentry);
		mutex_unlock(&inode->i_mutex);
		if (ret == 0) {
		ret = btrfs_sync_log(trans, root);
		if (ret == 0)
		@@ -1067,6 +1073,7 @@ out:
		(start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
		}
		}
		done:
		current->backing_dev_info = NULL;
		return num_written ? num_written : err;
		}

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