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/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index ee5b695c99a7..0e4c5c017fba 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1341,6 +1341,7 @@ xfs_fs_fill_super(
         sb->s_blocksize = mp->m_sb.sb_blocksize;
         sb->s_blocksize_bits = ffs(sb->s_blocksize) - 1;
         sb->s_maxbytes = xfs_max_file_offset(sb->s_blocksize_bits);
+        sb->s_max_links = XFS_MAXLINK;
         sb->s_time_gran = 1;
         set_posix_acl_flag(sb);