vfs: check i_nlink limits in vfs_{mkdir,rename_dir,link}

New field of struct super_block - ->s_max_links.  Maximal allowed
value of ->i_nlink or 0; in the latter case all checks still need
to be done in ->link/->mkdir/->rename instances.  Note that this
limit applies both to directoris and to non-directories.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 2 insertions, 13 deletions

diff --git a/fs/ufs/namei.c b/fs/ufs/namei.c
index 38cac199edff..a2281cadefa1 100644
--- a/fs/ufs/namei.c
+++ b/fs/ufs/namei.c
@@ -166,10 +166,6 @@ static int ufs_link (struct dentry * old_dentry, struct inode * dir,
         int error;
 
         lock_ufs(dir->i_sb);
-        if (inode->i_nlink >= UFS_LINK_MAX) {
-                unlock_ufs(dir->i_sb);
-                return -EMLINK;
-        }
 
         inode->i_ctime = CURRENT_TIME_SEC;
         inode_inc_link_count(inode);
@@ -183,10 +179,7 @@ static int ufs_link (struct dentry * old_dentry, struct inode * dir,
 static int ufs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
 {
         struct inode * inode;
-        int err = -EMLINK;
-
-        if (dir->i_nlink >= UFS_LINK_MAX)
-                goto out;
+        int err;
 
         lock_ufs(dir->i_sb);
         inode_inc_link_count(dir);
@@ -305,11 +298,6 @@ static int ufs_rename(struct inode *old_dir, struct dentry *old_dentry,
                         drop_nlink(new_inode);
                 inode_dec_link_count(new_inode);
         } else {
-                if (dir_de) {
-                        err = -EMLINK;
-                        if (new_dir->i_nlink >= UFS_LINK_MAX)
-                                goto out_dir;
-                }
                 err = ufs_add_link(new_dentry, old_inode);
                 if (err)
                         goto out_dir;
diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index 5246ee3e5607..ec25d09fcaa8 100644
--- a/fs/ufs/super.c
+++ b/fs/ufs/super.c
@@ -1157,6 +1157,7 @@ magic_found:
                             "fast symlink size (%u)\n", uspi->s_maxsymlinklen);
                 uspi->s_maxsymlinklen = maxsymlen;
         }
+        sb->s_max_links = UFS_LINK_MAX;
 
         inode = ufs_iget(sb, UFS_ROOTINO);
         if (IS_ERR(inode)) {