XFS - Revision history

Raion at 05:55, 25 December 2025

2025-12-25T05:55:46Z

← Older revision		Revision as of 05:55, 25 December 2025
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	'''XFS''' is a high-performance journaling file system created to replace [[EFS]] on IRIX, first appearing in [[IRIX 6.0 and 6.1\|IRIX 6.1]]. XFS increased volume size, marked a move from a synchronous filesystem to a journaled filesystem, and		'''XFS''' is a high-performance journaling file system created to replace [[EFS]] on IRIX, first appearing in [[IRIX 6.0 and 6.1\|IRIX 6.1]]. XFS increased volume size, marked a move from a synchronous filesystem to a journaled filesystem, and has since become a mainstay filesystem on GNU/Linux.

	== History ==		== History ==

Raion at 17:01, 5 October 2025

2025-10-05T17:01:32Z

← Older revision		Revision as of 17:01, 5 October 2025
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	The modern driver will write a header with a type, which will be interpreted as the start offset tag, but in reality is a type. This will break the filesystem under IRIX, and it's not correct per XFS either.		The modern driver will write a header with a type, which will be interpreted as the start offset tag, but in reality is a type. This will break the filesystem under IRIX, and it's not correct per XFS either.

			== Works Cited ==
	[[Category: Filesystems]]		[[Category: Filesystems]]

Raion at 17:00, 5 October 2025

2025-10-05T17:00:53Z

← Older revision		Revision as of 17:00, 5 October 2025
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	Since XFS was eventually moved to GNU/Linux for primary development, it has moved onto directory structure v3, v4 and v5, all of which are incompatible. Directory structure v2 support, the last IRIX supported version, was removed in kernel 3.17. All versions of GNU/Linux using a later kernel are unable to safely do anything to an XFS system.		Since XFS was eventually moved to GNU/Linux for primary development, it has moved onto directory structure v3, v4 and v5, all of which are incompatible. Directory structure v2 support, the last IRIX supported version, was removed in kernel 3.17. All versions of GNU/Linux using a later kernel are unable to safely do anything to an XFS system.

	From the source code:		From the source code<ref>https://github.com/torvalds/linux/blob/5792664070c62479b088e4909000582de3686396/fs/xfs/xfs_dir2_format.h</ref>:
	* Version 3 includes:		* Version 3 includes:
	*		*

Raion at 04:33, 4 October 2025

2025-10-04T04:33:09Z

← Older revision		Revision as of 04:33, 4 October 2025
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	} xfs_dir2_data_entry_t;		} xfs_dir2_data_entry_t;
	The modern driver will write a header with a type, which will be interpreted as the start offset tag, but in reality is a type. This will break the filesystem under IRIX, and it's not correct per XFS either.		The modern driver will write a header with a type, which will be interpreted as the start offset tag, but in reality is a type. This will break the filesystem under IRIX, and it's not correct per XFS either.

			[[Category: Filesystems]]

Raion at 04:30, 4 October 2025

2025-10-04T04:30:04Z

← Older revision		Revision as of 04:30, 4 October 2025
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	XFS is a high performance ~~filesystem introduced~~ in IRIX 5.3 and IRIX 6.~~0 to replace [[EFS~~]], a synchronous filesystem that ~~lacked performance~~, ~~stability~~ and ~~size capabilities afforded~~ by XFS.		'''XFS''' is a high-performance journaling file system created to replace [[EFS]] on IRIX, first appearing in [[IRIX 6.0 and 6.1\|IRIX 6.1]]. XFS increased volume size, marked a move from a synchronous filesystem to a journaled filesystem, and

			== History ==
			XFS is among the oldest journaling file systems available for UNIX systems, and has a mature, stable and well-debugged codebase. Development of XFS was started by Silicon Graphics in 1993, with first deployment being seen on IRIX 6.1 in 1994. The filesystem was later released under the GNU General Public License in May 2000, and ported to GNU/Linux, with the first distribution support appearing in 2001/2002.

			== Specifications ==

			=== Capacity ===
			XFS is a 64-bit file system. It supports a maximum file system size of 8 binary exabytes minus one byte, though this is subject to block limits imposed by the host operating system. IRIX is known to support up to 8 terabyte volumes.
			{\| class="wikitable"
			\|+
			\|Directory Structure
			\|B+ Trees
			\|-
			\|File Contents
			\|B+ Trees
			\|-
			\|Max Volume Size
			\|8 Terabytes
			\|-
			\|Max File Size
			\|4 Terabytes
			\|-
			\|Max Filename Length
			\|255 Bytes
			\|}

			== Interoperability with Linux XFS ==
			'''A modern GNU/Linux distribution is unable to safely read or write to XFS volumes created by IRIX. Data loss will occur!'''

			Since XFS was eventually moved to GNU/Linux for primary development, it has moved onto directory structure v3, v4 and v5, all of which are incompatible. Directory structure v2 support, the last IRIX supported version, was removed in kernel 3.17. All versions of GNU/Linux using a later kernel are unable to safely do anything to an XFS system.

			From the source code:
			* Version 3 includes:
			*
			* - a larger block header for CRC and identification purposes and so the
			* offsets of all the structures inside the blocks are different.
			*
			* - new magic numbers to be able to detect the v2/v3 types on the fly.
			*/
			This implies that the v2 and v3 headers are different. We later see in the code:
			/*
			* define a structure for all the verification fields we are adding to the
			* directory block structures. This will be used in several structures.
			* The magic number must be the first entry to align with all the dir2
			* structures so we determine how to decode them just by the magic number.
			*/
			struct xfs_dir3_blk_hdr {
			__be32 magic; /* magic number */
			__be32 crc; /* CRC of block */
			__be64 blkno; /* first block of the buffer */
			__be64 lsn; /* sequence number of last write */
			uuid_t uuid; /* filesystem we belong to */
			__be64 owner; /* inode that owns the block */
			};
			The headers are different. Per GitHub dev rozjin, if a v3 or later only driver tries to write to XFS v2:
			/*
			* Active entry in a data block.
			*
			* Aligned to 8 bytes. After the variable length name field there is a
			* 2 byte tag field, which can be accessed using xfs_dir3_data_entry_tag_p.
			*
			* For dir3 structures, there is file type field between the name and the tag.
			* This can only be manipulated by helper functions. It is packed hard against
			* the end of the name so any padding for rounding is between the file type and
			* the tag.
			*/
			typedef struct xfs_dir2_data_entry {
			__be64 inumber; /* inode number */
			__u8 namelen; /* name length */
			__u8 name[]; /* name bytes, no null */
			/* __u8 filetype; / / type of inode we point to */
			/* __be16 tag; / / starting offset of us */
			} xfs_dir2_data_entry_t;
			The modern driver will write a header with a type, which will be interpreted as the start offset tag, but in reality is a type. This will break the filesystem under IRIX, and it's not correct per XFS either.

Raion: Created page with "XFS is a high performance filesystem introduced in IRIX 5.3 and IRIX 6.0 to replace EFS, a synchronous filesystem that lacked performance, stability and size capabilities afforded by XFS."

2025-09-21T03:34:27Z

Created page with "XFS is a high performance filesystem introduced in IRIX 5.3 and IRIX 6.0 to replace EFS, a synchronous filesystem that lacked performance, stability and size capabilities afforded by XFS."

New page

XFS is a high performance filesystem introduced in IRIX 5.3 and IRIX 6.0 to replace [[EFS]], a synchronous filesystem that lacked performance, stability and size capabilities afforded by XFS.