Samsung releases new exFAT driver for Linux kernel

Samsung suggested for inclusion in the Linux kernel, a set of patches with the implementation of a new exFAT driver based on the current “sdfat” codebase developed for Samsung Android smartphone firmware. If the patches are accepted, they will be included in the Linux 5.6 kernel, which is expected to be released in 2-3 months. Compared to the exFAT driver previously added to the kernel, the new driver delivers a performance boost of around 10%.

The main differences between the edition of the sdfat driver for the main Linux kernel and the driver used by Samsung in Android are:

• The code with the implementation of the VFAT file system has been removed, since this file system is already separately supported in the kernel (fs/fat);
• Driver renamed from sdfat to exfat;
• The code has been refactored. Source texts are given to the requirements for coding for the Linux kernel;
• Metadata operations such as creating files, searching for file system elements (lookup) and determining the contents of a directory (readdir) have been optimized.
• Bugs identified during additional testing have been fixed.

Recall that after Microsoft опубликовала public specifications and allowed royalty-free use of exFAT patents in Linux, an exFAT driver, also developed by Samsung but based on legacy code (version 1.2.9). Enthusiasts from Android firmware was ported new sdFAT (2.x) driver, but Samsung decided to promote this driver to the mainstream Linux kernel on its own. In addition, Paragon Software has opened alternative driver, previously shipped in the proprietary driver suite.

The exFAT file system was created by Microsoft to address the limitations of FAT32 when used on large flash drives. Support for the exFAT file system was introduced in Windows Vista Service Pack 1 and Windows XP with Service Pack 2. The maximum file size compared to FAT32 was expanded from 4 GB to 16 exabytes, the maximum partition size limit of 32 GB was removed, to reduce fragmentation and increase speed, a bitmap of free blocks has been introduced, the limit on the number of files in one directory has been raised to 65 thousand, and the ability to store ACLs has been provided.

Source: opennet.ru