vfs: Add support to debug umount failures

When umount of a partition fails with EBUSY there is
no indication as to what is keeping the mount point busy.

Add support to print a kernel log showing what files
are open on this mount point.

Also add a new new config option CONFIG_FILE_TABLE_DEBUG to
enable this feature.

Change-Id: Id7a3f5e7291b22ffd0f265848ec0a9757f713561
Signed-off-by: Nikhilesh Reddy <reddyn@codeaurora.org>
Signed-off-by: Ankit Jain <ankijain@codeaurora.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 816b6e8e934e..b5dfe2c5b51e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3379,6 +3379,8 @@ out2:
 				error = -ESTALE;
 		}
 		file = ERR_PTR(error);
+	} else {
+		global_filetable_add(file);
 	}
 	return file;
 }