[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, 6 insertions, 1 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4bb7087..26d3c61 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1225,9 +1225,14 @@ static inline void inode_inc_link_count(struct inode *inode)
 	mark_inode_dirty(inode);
 }
 
-static inline void inode_dec_link_count(struct inode *inode)
+static inline void drop_nlink(struct inode *inode)
 {
 	inode->i_nlink--;
+}
+
+static inline void inode_dec_link_count(struct inode *inode)
+{
+	drop_nlink(inode);
 	mark_inode_dirty(inode);
 }