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, 3 insertions, 0 deletions

diff --git a/fs/udf/super.c b/fs/udf/super.c
index c09a84daaf50..8d8b25336fbb 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -75,6 +75,8 @@
 
 #define UDF_DEFAULT_BLOCKSIZE 2048
 
+enum { UDF_MAX_LINKS = 0xffff };
+
 /* These are the "meat" - everything else is stuffing */
 static int udf_fill_super(struct super_block *, void *, int);
 static void udf_put_super(struct super_block *);
@@ -2042,6 +2044,7 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
                 goto error_out;
         }
         sb->s_maxbytes = MAX_LFS_FILESIZE;
+        sb->s_max_links = UDF_MAX_LINKS;
         return 0;
 
 error_out: