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>

1 files changed, 1 insertions, 0 deletions

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;