[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, 12 deletions

diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index ab9a7629d23e..d14d25534aa8 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -878,8 +878,7 @@ static int udf_rmdir(struct inode * dir, struct dentry * dentry)
                         inode->i_nlink);
         inode->i_nlink = 0;
         inode->i_size = 0;
-        mark_inode_dirty(inode);
-        dir->i_nlink --;
+        inode_dec_link_count(inode);
         inode->i_ctime = dir->i_ctime = dir->i_mtime = current_fs_time(dir->i_sb);
         mark_inode_dirty(dir);
 
@@ -923,8 +922,7 @@ static int udf_unlink(struct inode * dir, struct dentry * dentry)
                 goto end_unlink;
         dir->i_ctime = dir->i_mtime = current_fs_time(dir->i_sb);
         mark_inode_dirty(dir);
-        inode->i_nlink--;
-        mark_inode_dirty(inode);
+        inode_dec_link_count(inode);
         inode->i_ctime = dir->i_ctime;
         retval = 0;
 
@@ -1101,8 +1099,7 @@ out:
         return err;
 
 out_no_entry:
-        inode->i_nlink--;
-        mark_inode_dirty(inode);
+        inode_dec_link_count(inode);
         iput(inode);
         goto out;
 }
@@ -1261,9 +1258,8 @@ static int udf_rename (struct inode * old_dir, struct dentry * old_dentry,
 
         if (new_inode)
         {
-                new_inode->i_nlink--;
                 new_inode->i_ctime = current_fs_time(new_inode->i_sb);
-                mark_inode_dirty(new_inode);
+                inode_dec_link_count(new_inode);
         }
         old_dir->i_ctime = old_dir->i_mtime = current_fs_time(old_dir->i_sb);
         mark_inode_dirty(old_dir);
@@ -1279,12 +1275,10 @@ static int udf_rename (struct inode * old_dir, struct dentry * old_dentry,
                 }
                 else
                         mark_buffer_dirty_inode(dir_bh, old_inode);
-                old_dir->i_nlink --;
-                mark_inode_dirty(old_dir);
+                inode_dec_link_count(old_dir);
                 if (new_inode)
                 {
-                        new_inode->i_nlink --;
-                        mark_inode_dirty(new_inode);
+                        inode_dec_link_count(new_inode);
                 }
                 else
                 {