[PATCH] r/o bind mounts: unlink: monitor i_nlink

When a filesystem decrements i_nlink to zero, it means that a write must be
performed in order to drop the inode from the filesystem.

We're shortly going to have keep filesystems from being remounted r/o between
the time that this i_nlink decrement and that write occurs.

So, add a little helper function to do the decrements.  We'll tie into it in a
bit to note when i_nlink hits zero.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 5 deletions

diff --git a/fs/libfs.c b/fs/libfs.c
index 3793aaa..9204feb 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -275,7 +275,7 @@ int simple_unlink(struct inode *dir, struct dentry *dentry)
 	struct inode *inode = dentry->d_inode;
 
 	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
-	inode->i_nlink--;
+	drop_nlink(inode);
 	dput(dentry);
 	return 0;
 }
@@ -285,9 +285,9 @@ int simple_rmdir(struct inode *dir, struct dentry *dentry)
 	if (!simple_empty(dentry))
 		return -ENOTEMPTY;
 
-	dentry->d_inode->i_nlink--;
+	drop_nlink(dentry->d_inode);
 	simple_unlink(dir, dentry);
-	dir->i_nlink--;
+	drop_nlink(dir);
 	return 0;
 }
 
@@ -303,9 +303,9 @@ int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
 	if (new_dentry->d_inode) {
 		simple_unlink(new_dir, new_dentry);
 		if (they_are_dirs)
-			old_dir->i_nlink--;
+			drop_nlink(old_dir);
 	} else if (they_are_dirs) {
-		old_dir->i_nlink--;
+		drop_nlink(old_dir);
 		new_dir->i_nlink++;
 	}