[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, 7 insertions, 7 deletions

diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c
index 235e77b..14c55ad 100644
--- a/fs/ext3/namei.c
+++ b/fs/ext3/namei.c
@@ -1621,7 +1621,7 @@ static inline void ext3_inc_count(handle_t *handle, struct inode *inode)
 
 static inline void ext3_dec_count(handle_t *handle, struct inode *inode)
 {
-	inode->i_nlink--;
+	drop_nlink(inode);
 }
 
 static int ext3_add_nondir(handle_t *handle,
@@ -1743,7 +1743,7 @@ retry:
 	inode->i_size = EXT3_I(inode)->i_disksize = inode->i_sb->s_blocksize;
 	dir_block = ext3_bread (handle, inode, 0, 1, &err);
 	if (!dir_block) {
-		inode->i_nlink--; /* is this nlink == 0? */
+		drop_nlink(inode); /* is this nlink == 0? */
 		ext3_mark_inode_dirty(handle, inode);
 		iput (inode);
 		goto out_stop;
@@ -2053,7 +2053,7 @@ static int ext3_rmdir (struct inode * dir, struct dentry *dentry)
 	ext3_orphan_add(handle, inode);
 	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
 	ext3_mark_inode_dirty(handle, inode);
-	dir->i_nlink--;
+	drop_nlink(dir);
 	ext3_update_dx_flag(dir);
 	ext3_mark_inode_dirty(handle, dir);
 
@@ -2104,7 +2104,7 @@ static int ext3_unlink(struct inode * dir, struct dentry *dentry)
 	dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
 	ext3_update_dx_flag(dir);
 	ext3_mark_inode_dirty(handle, dir);
-	inode->i_nlink--;
+	drop_nlink(inode);
 	if (!inode->i_nlink)
 		ext3_orphan_add(handle, inode);
 	inode->i_ctime = dir->i_ctime;
@@ -2326,7 +2326,7 @@ static int ext3_rename (struct inode * old_dir, struct dentry *old_dentry,
 	}
 
 	if (new_inode) {
-		new_inode->i_nlink--;
+		drop_nlink(new_inode);
 		new_inode->i_ctime = CURRENT_TIME_SEC;
 	}
 	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
@@ -2337,9 +2337,9 @@ static int ext3_rename (struct inode * old_dir, struct dentry *old_dentry,
 		PARENT_INO(dir_bh->b_data) = cpu_to_le32(new_dir->i_ino);
 		BUFFER_TRACE(dir_bh, "call ext3_journal_dirty_metadata");
 		ext3_journal_dirty_metadata(handle, dir_bh);
-		old_dir->i_nlink--;
+		drop_nlink(old_dir);
 		if (new_inode) {
-			new_inode->i_nlink--;
+			drop_nlink(new_inode);
 		} else {
 			new_dir->i_nlink++;
 			ext3_update_dx_flag(new_dir);