[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, 3 insertions, 6 deletions

diff --git a/fs/bfs/dir.c b/fs/bfs/dir.c
index dcf04cb..ce05d16 100644
--- a/fs/bfs/dir.c
+++ b/fs/bfs/dir.c
@@ -117,8 +117,7 @@ static int bfs_create(struct inode * dir, struct dentry * dentry, int mode,
 
 	err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, inode->i_ino);
 	if (err) {
-		inode->i_nlink--;
-		mark_inode_dirty(inode);
+		inode_dec_link_count(inode);
 		iput(inode);
 		unlock_kernel();
 		return err;
@@ -196,9 +195,8 @@ static int bfs_unlink(struct inode * dir, struct dentry * dentry)
 	mark_buffer_dirty(bh);
 	dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
 	mark_inode_dirty(dir);
-	inode->i_nlink--;
 	inode->i_ctime = dir->i_ctime;
-	mark_inode_dirty(inode);
+	inode_dec_link_count(inode);
 	error = 0;
 
 out_brelse:
@@ -249,9 +247,8 @@ static int bfs_rename(struct inode * old_dir, struct dentry * old_dentry,
 	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
 	mark_inode_dirty(old_dir);
 	if (new_inode) {
-		new_inode->i_nlink--;
 		new_inode->i_ctime = CURRENT_TIME_SEC;
-		mark_inode_dirty(new_inode);
+		inode_dec_link_count(new_inode);
 	}
 	mark_buffer_dirty(old_bh);
 	error = 0;