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, 3 insertions, 13 deletions

diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 08bf46edf9c4..38de8f234b94 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -32,8 +32,6 @@
 #include <linux/crc-itu-t.h>
 #include <linux/exportfs.h>
 
-enum { UDF_MAX_LINKS = 0xffff };
-
 static inline int udf_match(int len1, const unsigned char *name1, int len2,
                             const unsigned char *name2)
 {
@@ -649,10 +647,6 @@ static int udf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
         struct udf_inode_info *dinfo = UDF_I(dir);
         struct udf_inode_info *iinfo;
 
-        err = -EMLINK;
-        if (dir->i_nlink >= UDF_MAX_LINKS)
-                goto out;
-
         err = -EIO;
         inode = udf_new_inode(dir, S_IFDIR | mode, &err);
         if (!inode)
@@ -1032,9 +1026,6 @@ static int udf_link(struct dentry *old_dentry, struct inode *dir,
         struct fileIdentDesc cfi, *fi;
         int err;
 
-        if (inode->i_nlink >= UDF_MAX_LINKS)
-                return -EMLINK;
-
         fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err);
         if (!fi) {
                 return err;
@@ -1126,10 +1117,6 @@ static int udf_rename(struct inode *old_dir, struct dentry *old_dentry,
                 if (udf_get_lb_pblock(old_inode->i_sb, &tloc, 0) !=
                                 old_dir->i_ino)
                         goto end_rename;
-
-                retval = -EMLINK;
-                if (!new_inode && new_dir->i_nlink >= UDF_MAX_LINKS)
-                        goto end_rename;
         }
         if (!nfi) {
                 nfi = udf_add_entry(new_dir, new_dentry, &nfibh, &ncfi,
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: