Re: Problems with the max value for create directory

[Toshiyuki Okajima <toshi.okajima@xxxxxxxxxxxxxx>]

Hi,

Zhang Xiliang wrote:
> Hi,
>
> I creat 65537 long directories and failed when the block size is 1024.
>
> # mkfs.ext4dev -b 1024 -I 256 /dev/hda3
> # tune2fs -E test_fs -O extents /dev/hda3
> # mount -t ext4dev /dev/hda3 /mnt
> # ./create_long_dirs 65537 /mnt
>
> The code of create_long_dirs.c:

ext4 filesystem cannot make over 65000 links toward a file.
(ext3 filesystem cannot make over 32000 links toward a file.)
This test makes over 65000 links toward /mnt-directory.
(Creating 65000 sub-directories makes 65000 links toward /mnt-directory.)

static int ext4_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
         handle_t *handle;
         struct inode *inode;
         struct buffer_head *dir_block;
         struct ext4_dir_entry_2 *de;
         int err, retries = 0;

         if (EXT4_DIR_LINK_MAX(dir))
　　　　　^^^^^^^^^^^^^^^^^^^^^^^^^^^　　　　
                 return -EMLINK;

This limit is ext4's specification.

Regards,
Toshiyuki Okajima

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