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, 12 deletions

diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index 080419814bae..dffb86536285 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -195,9 +195,6 @@ static int ext2_link (struct dentry * old_dentry, struct inode * dir,
         struct inode *inode = old_dentry->d_inode;
         int err;
 
-        if (inode->i_nlink >= EXT2_LINK_MAX)
-                return -EMLINK;
-
         dquot_initialize(dir);
 
         inode->i_ctime = CURRENT_TIME_SEC;
@@ -217,10 +214,7 @@ static int ext2_link (struct dentry * old_dentry, struct inode * dir,
 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
 {
         struct inode * inode;
-        int err = -EMLINK;
-
-        if (dir->i_nlink >= EXT2_LINK_MAX)
-                goto out;
+        int err;
 
         dquot_initialize(dir);
 
@@ -346,11 +340,6 @@ static int ext2_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 >= EXT2_LINK_MAX)
-                                goto out_dir;
-                }
                 err = ext2_add_link(new_dentry, old_inode);
                 if (err)
                         goto out_dir;
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 0090595beb28..9f6766a3ac1e 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -919,6 +919,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
         }
 
         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
+        sb->s_max_links = EXT2_LINK_MAX;
 
         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;