[PATCH 12/17] Unionfs: branch management/configuration fixes

[Erez Zadok <ezk@cs.sunysb.edu>]

Remove unnecessary calls to update branch m/ctimes, and use them only when
needed.  Update branch vfsmounts after operations that could cause a copyup.

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
---
 fs/unionfs/commonfops.c |    9 +++------
 fs/unionfs/copyup.c     |    3 ++-
 fs/unionfs/dentry.c     |    1 +
 fs/unionfs/mmap.c       |   17 ++++-------------
 fs/unionfs/rename.c     |    7 +++++--
 5 files changed, 15 insertions(+), 22 deletions(-)

diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c
index 491e2ff..2add167 100644
--- a/fs/unionfs/commonfops.c
+++ b/fs/unionfs/commonfops.c
@@ -604,6 +604,7 @@ out:
 	}
 out_nofree:
 	if (!err) {
+		unionfs_postcopyup_setmnt(dentry);
 		unionfs_copy_attr_times(inode);
 		unionfs_check_file(file);
 		unionfs_check_inode(inode);
@@ -839,13 +840,9 @@ int unionfs_flush(struct file *file, fl_owner_t id)
 
 	}
 
-	/* on success, update our times */
-	unionfs_copy_attr_times(dentry->d_inode);
-	/* parent time could have changed too (async) */
-	unionfs_copy_attr_times(dentry->d_parent->d_inode);
-
 out:
-	unionfs_check_file(file);
+	if (!err)
+		unionfs_check_file(file);
 	unionfs_unlock_dentry(file->f_path.dentry);
 	unionfs_read_unlock(dentry->d_sb);
 	return err;
diff --git a/fs/unionfs/copyup.c b/fs/unionfs/copyup.c
index 9beac01..f71bddf 100644
--- a/fs/unionfs/copyup.c
+++ b/fs/unionfs/copyup.c
@@ -819,7 +819,8 @@ begin:
 	 * update times of this dentry, but also the parent, because if
 	 * we changed, the parent may have changed too.
 	 */
-	unionfs_copy_attr_times(parent_dentry->d_inode);
+	fsstack_copy_attr_times(parent_dentry->d_inode,
+				lower_parent_dentry->d_inode);
 	unionfs_copy_attr_times(child_dentry->d_inode);
 
 	parent_dentry = child_dentry;
diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c
index 17b297d..a956b94 100644
--- a/fs/unionfs/dentry.c
+++ b/fs/unionfs/dentry.c
@@ -482,6 +482,7 @@ static int unionfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
 	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
 	err = __unionfs_d_revalidate_chain(dentry, nd, false);
 	if (likely(err > 0)) { /* true==1: dentry is valid */
+		unionfs_postcopyup_setmnt(dentry);
 		unionfs_check_dentry(dentry);
 		unionfs_check_nd(nd);
 	}
diff --git a/fs/unionfs/mmap.c b/fs/unionfs/mmap.c
index ad770ac..d6ac61e 100644
--- a/fs/unionfs/mmap.c
+++ b/fs/unionfs/mmap.c
@@ -227,20 +227,11 @@ static int unionfs_prepare_write(struct file *file, struct page *page,
 	int err;
 
 	unionfs_read_lock(file->f_path.dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-	/*
-	 * This is the only place where we unconditionally copy the lower
-	 * attribute times before calling unionfs_file_revalidate.  The
-	 * reason is that our ->write calls do_sync_write which in turn will
-	 * call our ->prepare_write and then ->commit_write.  Before our
-	 * ->write is called, the lower mtimes are in sync, but by the time
-	 * the VFS calls our ->commit_write, the lower mtimes have changed.
-	 * Therefore, the only reasonable time for us to sync up from the
-	 * changed lower mtimes, and avoid an invariant violation warning,
-	 * is here, in ->prepare_write.
-	 */
-	unionfs_copy_attr_times(file->f_path.dentry->d_inode);
 	err = unionfs_file_revalidate(file, true);
-	unionfs_check_file(file);
+	if (!err) {
+		unionfs_copy_attr_times(file->f_path.dentry->d_inode);
+		unionfs_check_file(file);
+	}
 	unionfs_read_unlock(file->f_path.dentry->d_sb);
 
 	return err;
diff --git a/fs/unionfs/rename.c b/fs/unionfs/rename.c
index 5ab13f9..cc16eb2 100644
--- a/fs/unionfs/rename.c
+++ b/fs/unionfs/rename.c
@@ -138,6 +138,11 @@ static int __unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	err = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 			 lower_new_dir_dentry->d_inode, lower_new_dentry);
 out_err_unlock:
+	if (!err) {
+		/* update parent dir times */
+		fsstack_copy_attr_times(old_dir, lower_old_dir_dentry->d_inode);
+		fsstack_copy_attr_times(new_dir, lower_new_dir_dentry->d_inode);
+	}
 	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 	lockdep_on();
 
@@ -526,8 +531,6 @@ int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 		}
 	}
 	/* if all of this renaming succeeded, update our times */
-	unionfs_copy_attr_times(old_dir);
-	unionfs_copy_attr_times(new_dir);
 	unionfs_copy_attr_times(old_dentry->d_inode);
 	unionfs_copy_attr_times(new_dentry->d_inode);
 	unionfs_check_inode(old_dir);
-- 
1.5.2.2