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, 1 insertions, 3 deletions

diff --git a/fs/logfs/dir.c b/fs/logfs/dir.c
index 3de7a32cadbe..4aea231fc9e6 100644
--- a/fs/logfs/dir.c
+++ b/fs/logfs/dir.c
@@ -558,9 +558,6 @@ static int logfs_link(struct dentry *old_dentry, struct inode *dir,
 {
         struct inode *inode = old_dentry->d_inode;
 
-        if (inode->i_nlink >= LOGFS_LINK_MAX)
-                return -EMLINK;
-
         inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
         ihold(inode);
         inc_nlink(inode);
diff --git a/fs/logfs/super.c b/fs/logfs/super.c
index c9ee7f5d1caf..b1a491a5fe78 100644
--- a/fs/logfs/super.c
+++ b/fs/logfs/super.c
@@ -542,6 +542,7 @@ static struct dentry *logfs_get_sb_device(struct logfs_super *super,
          * the filesystem incompatible with 32bit systems.
          */
         sb->s_maxbytes  = (1ull << 43) - 1;
+        sb->s_max_links = LOGFS_LINK_MAX;
         sb->s_op        = &logfs_super_operations;
         sb->s_flags     = flags | MS_NOATIME;