-This is the implementation of the SystemV/Coherent filesystem for Linux.
It implements all of
- Xenix FS,
- SystemV/386 FS,
- Coherent FS.
-This is version beta 4.
-
To install:
* Answer the 'System V and Coherent filesystem support' question with 'y'
when configuring the kernel.
for this FS on hard disk yet.
-Please report any bugs and suggestions to
- Bruno Haible <haible@ma2s2.mathematik.uni-karlsruhe.de>
- Pascal Haible <haible@izfm.uni-stuttgart.de>
- Krzysztof G. Baranowski <kgb@manjak.knm.org.pl>
+These filesystems are rather similar. Here is a comparison with Minix FS:
+
+* Linux fdisk reports on partitions
+ - Minix FS 0x81 Linux/Minix
+ - Xenix FS ??
+ - SystemV FS ??
+ - Coherent FS 0x08 AIX bootable
+
+* Size of a block or zone (data allocation unit on disk)
+ - Minix FS 1024
+ - Xenix FS 1024 (also 512 ??)
+ - SystemV FS 1024 (also 512 and 2048)
+ - Coherent FS 512
+
+* General layout: all have one boot block, one super block and
+ separate areas for inodes and for directories/data.
+ On SystemV Release 2 FS (e.g. Microport) the first track is reserved and
+ all the block numbers (including the super block) are offset by one track.
+
+* Byte ordering of "short" (16 bit entities) on disk:
+ - Minix FS little endian 0 1
+ - Xenix FS little endian 0 1
+ - SystemV FS little endian 0 1
+ - Coherent FS little endian 0 1
+ Of course, this affects only the file system, not the data of files on it!
+
+* Byte ordering of "long" (32 bit entities) on disk:
+ - Minix FS little endian 0 1 2 3
+ - Xenix FS little endian 0 1 2 3
+ - SystemV FS little endian 0 1 2 3
+ - Coherent FS PDP-11 2 3 0 1
+ Of course, this affects only the file system, not the data of files on it!
+
+* Inode on disk: "short", 0 means non-existent, the root dir ino is:
+ - Minix FS 1
+ - Xenix FS, SystemV FS, Coherent FS 2
+
+* Maximum number of hard links to a file:
+ - Minix FS 250
+ - Xenix FS ??
+ - SystemV FS ??
+ - Coherent FS >=10000
+
+* Free inode management:
+ - Minix FS a bitmap
+ - Xenix FS, SystemV FS, Coherent FS
+ There is a cache of a certain number of free inodes in the super-block.
+ When it is exhausted, new free inodes are found using a linear search.
+
+* Free block management:
+ - Minix FS a bitmap
+ - Xenix FS, SystemV FS, Coherent FS
+ Free blocks are organized in a "free list". Maybe a misleading term,
+ since it is not true that every free block contains a pointer to
+ the next free block. Rather, the free blocks are organized in chunks
+ of limited size, and every now and then a free block contains pointers
+ to the free blocks pertaining to the next chunk; the first of these
+ contains pointers and so on. The list terminates with a "block number"
+ 0 on Xenix FS and SystemV FS, with a block zeroed out on Coherent FS.
+
+* Super-block location:
+ - Minix FS block 1 = bytes 1024..2047
+ - Xenix FS block 1 = bytes 1024..2047
+ - SystemV FS bytes 512..1023
+ - Coherent FS block 1 = bytes 512..1023
+
+* Super-block layout:
+ - Minix FS
+ unsigned short s_ninodes;
+ unsigned short s_nzones;
+ unsigned short s_imap_blocks;
+ unsigned short s_zmap_blocks;
+ unsigned short s_firstdatazone;
+ unsigned short s_log_zone_size;
+ unsigned long s_max_size;
+ unsigned short s_magic;
+ - Xenix FS, SystemV FS, Coherent FS
+ unsigned short s_firstdatazone;
+ unsigned long s_nzones;
+ unsigned short s_fzone_count;
+ unsigned long s_fzones[NICFREE];
+ unsigned short s_finode_count;
+ unsigned short s_finodes[NICINOD];
+ char s_flock;
+ char s_ilock;
+ char s_modified;
+ char s_rdonly;
+ unsigned long s_time;
+ short s_dinfo[4]; -- SystemV FS only
+ unsigned long s_free_zones;
+ unsigned short s_free_inodes;
+ short s_dinfo[4]; -- Xenix FS only
+ unsigned short s_interleave_m,s_interleave_n; -- Coherent FS only
+ char s_fname[6];
+ char s_fpack[6];
+ then they differ considerably:
+ Xenix FS
+ char s_clean;
+ char s_fill[371];
+ long s_magic;
+ long s_type;
+ SystemV FS
+ long s_fill[12 or 14];
+ long s_state;
+ long s_magic;
+ long s_type;
+ Coherent FS
+ unsigned long s_unique;
+ Note that Coherent FS has no magic.
+
+* Inode layout:
+ - Minix FS
+ unsigned short i_mode;
+ unsigned short i_uid;
+ unsigned long i_size;
+ unsigned long i_time;
+ unsigned char i_gid;
+ unsigned char i_nlinks;
+ unsigned short i_zone[7+1+1];
+ - Xenix FS, SystemV FS, Coherent FS
+ unsigned short i_mode;
+ unsigned short i_nlink;
+ unsigned short i_uid;
+ unsigned short i_gid;
+ unsigned long i_size;
+ unsigned char i_zone[3*(10+1+1+1)];
+ unsigned long i_atime;
+ unsigned long i_mtime;
+ unsigned long i_ctime;
+
+* Regular file data blocks are organized as
+ - Minix FS
+ 7 direct blocks
+ 1 indirect block (pointers to blocks)
+ 1 double-indirect block (pointer to pointers to blocks)
+ - Xenix FS, SystemV FS, Coherent FS
+ 10 direct blocks
+ 1 indirect block (pointers to blocks)
+ 1 double-indirect block (pointer to pointers to blocks)
+ 1 triple-indirect block (pointer to pointers to pointers to blocks)
+
+* Inode size, inodes per block
+ - Minix FS 32 32
+ - Xenix FS 64 16
+ - SystemV FS 64 16
+ - Coherent FS 64 8
+
+* Directory entry on disk
+ - Minix FS
+ unsigned short inode;
+ char name[14/30];
+ - Xenix FS, SystemV FS, Coherent FS
+ unsigned short inode;
+ char name[14];
+
+* Dir entry size, dir entries per block
+ - Minix FS 16/32 64/32
+ - Xenix FS 16 64
+ - SystemV FS 16 64
+ - Coherent FS 16 32
+
+* How to implement symbolic links such that the host fsck doesn't scream:
+ - Minix FS normal
+ - Xenix FS kludge: as regular files with chmod 1000
+ - SystemV FS ??
+ - Coherent FS kludge: as regular files with chmod 1000
-Bruno Haible
-<haible@ma2s2.mathematik.uni-karlsruhe.de>
+Notation: We often speak of a "block" but mean a zone (the allocation unit)
+and not the disk driver's notion of "block".
+++ /dev/null
-Mon, 15 Dec 1997 Krzysztof G. Baranowski <kgb@manjak.knm.org.pl>
- * namei.c: struct sysv_dir_inode_operations updated to use dentries.
-
-Fri, 23 Jan 1998 Krzysztof G. Baranowski <kgb@manjak.knm.org.pl>
- * inode.c: corrected 1 track offset setting (in sb->sv_block_base).
- Originally it was overridden (by setting to zero)
- in detected_[xenix,sysv4,sysv2,coherent]. Thanks
- to Andrzej Krzysztofowicz <ankry@mif.pg.gda.pl>
- for identifying the problem.
-
-Tue, 27 Jan 1998 Krzysztof G. Baranowski <kgb@manjak.knm.org.pl>
- * inode.c: added 2048-byte block support to SystemV FS.
- Merged detected_bs[512,1024,2048]() into one function:
- void detected_bs (u_char type, struct super_block *sb).
- Thanks to Andrzej Krzysztofowicz <ankry@mif.pg.gda.pl>
- for the patch.
-
-Wed, 4 Feb 1998 Krzysztof G. Baranowski <kgb@manjak.knm.org.pl>
- * namei.c: removed static subdir(); is_subdir() from dcache.c
- is used instead. Cosmetic changes.
-
-Thu, 3 Dec 1998 Al Viro (viro@parcelfarce.linux.theplanet.co.uk)
- * namei.c (sysv_rmdir):
- Bugectomy: old check for victim being busy
- (inode->i_count) wasn't replaced (with checking
- dentry->d_count) and escaped Linus in the last round
- of changes. Shot and buried.
-
-Wed, 9 Dec 1998 AV
- * namei.c (do_sysv_rename):
- Fixed incorrect check for other owners + race.
- Removed checks that went to VFS.
- * namei.c (sysv_unlink):
- Removed checks that went to VFS.
-
-Thu, 10 Dec 1998 AV
- * namei.c (do_mknod):
- Removed dead code - mknod is never asked to
- create a symlink or directory. Incidentially,
- it wouldn't do it right if it would be called.
-
-Sat, 26 Dec 1998 KGB
- * inode.c (detect_sysv4):
- Added detection of expanded s_type field (0x10,
- 0x20 and 0x30). Forced read-only access in this case.
-
-Sun, 21 Mar 1999 AV
- * namei.c (sysv_link):
- Fixed i_count usage that resulted in dcache corruption.
- * inode.c:
- Filled ->delete_inode() method with sysv_delete_inode().
- sysv_put_inode() is gone, as it tried to do ->delete_
- _inode()'s job.
- * ialloc.c: (sysv_free_inode):
- Fixed race.
-
-Sun, 30 Apr 1999 AV
- * namei.c (sysv_mknod):
- Removed dead code (S_IFREG case is now passed to
- ->create() by VFS).
+++ /dev/null
-Thu Feb 14 2002 Andrew Morton <akpm@zip.com.au>
-
- * dir_commit_chunk(): call writeout_one_page() as well as
- waitfor_one_page() for IS_SYNC directories, so that we
- actually do sync the directory. (forward-port from 2.4).
-
-Thu Feb 7 2002 Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk>
-
- * super.c: switched to ->get_sb()
- * ChangeLog: fixed dates ;-)
-
-2002-01-24 David S. Miller <davem@redhat.com>
-
- * inode.c: Include linux/init.h
-
-Mon Jan 21 2002 Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk>
- * ialloc.c (sysv_new_inode): zero SYSV_I(inode)->i_data out.
- * i_vnode renamed to vfs_inode. Sorry, but let's keep that
- consistent.
-
-Sat Jan 19 2002 Christoph Hellwig <hch@infradead.org>
-
- * include/linux/sysv_fs.h (SYSV_I): Get fs-private inode data using
- list_entry() instead of inode->u.
- * include/linux/sysv_fs_i.h: Add 'struct inode i_vnode' field to
- sysv_inode_info structure.
- * inode.c: Include <linux/slab.h>, implement alloc_inode/destroy_inode
- sop methods, add infrastructure for per-fs inode slab cache.
- * super.c (init_sysv_fs): Initialize inode cache, recover properly
- in the case of failed register_filesystem for V7.
- (exit_sysv_fs): Destroy inode cache.
-
-Sat Jan 19 2002 Christoph Hellwig <hch@infradead.org>
-
- * include/linux/sysv_fs.h: Include <linux/sysv_fs_i.h>, declare SYSV_I().
- * dir.c (sysv_find_entry): Use SYSV_I() instead of ->u.sysv_i to
- access fs-private inode data.
- * ialloc.c (sysv_new_inode): Likewise.
- * inode.c (sysv_read_inode): Likewise.
- (sysv_update_inode): Likewise.
- * itree.c (get_branch): Likewise.
- (sysv_truncate): Likewise.
- * symlink.c (sysv_readlink): Likewise.
- (sysv_follow_link): Likewise.
-
-Fri Jan 4 2002 Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk>
-
- * ialloc.c (sysv_free_inode): Use sb->s_id instead of bdevname().
- * inode.c (sysv_read_inode): Likewise.
- (sysv_update_inode): Likewise.
- (sysv_sync_inode): Likewise.
- * super.c (detect_sysv): Likewise.
- (complete_read_super): Likewise.
- (sysv_read_super): Likewise.
- (v7_read_super): Likewise.
-
-Sun Dec 30 2001 Manfred Spraul <manfred@colorfullife.com>
-
- * dir.c (dir_commit_chunk): Do not set dir->i_version.
- (sysv_readdir): Likewise.
-
-Thu Dec 27 2001 Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk>
-
- * itree.c (get_block): Use map_bh() to fill out bh_result.
-
-Tue Dec 25 2001 Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk>
-
- * super.c (sysv_read_super): Use sb_set_blocksize() to set blocksize.
- (v7_read_super): Likewise.
-
-Tue Nov 27 2001 Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk>
-
- * itree.c (get_block): Change type for iblock argument to sector_t.
- * super.c (sysv_read_super): Set s_blocksize early.
- (v7_read_super): Likewise.
- * balloc.c (sysv_new_block): Use sb_bread(). instead of bread().
- (sysv_count_free_blocks): Likewise.
- * ialloc.c (sysv_raw_inode): Likewise.
- * itree.c (get_branch): Likewise.
- (free_branches): Likewise.
- * super.c (sysv_read_super): Likewise.
- (v7_read_super): Likewise.
-
-Sat Dec 15 2001 Christoph Hellwig <hch@infradead.org>
-
- * inode.c (sysv_read_inode): Mark inode as bad in case of failure.
- * super.c (complete_read_super): Check for bad root inode.
-
-Wed Nov 21 2001 Andrew Morton <andrewm@uow.edu.au>
-
- * file.c (sysv_sync_file): Call fsync_inode_data_buffers.
-
-Fri Oct 26 2001 Christoph Hellwig <hch@infradead.org>
-
- * dir.c, ialloc.c, namei.c, include/linux/sysv_fs_i.h:
- Implement per-Inode lookup offset cache.
- Modelled after Ted's ext2 patch.
-
-Fri Oct 26 2001 Christoph Hellwig <hch@infradead.org>
-
- * inode.c, super.c, include/linux/sysv_fs.h,
- include/linux/sysv_fs_sb.h:
- Remove symlink faking. Noone really wants to use these as
- linux filesystems and native OSes don't support it anyway.
-
-
+++ /dev/null
-This is the implementation of the SystemV/Coherent filesystem for Linux.
-It grew out of separate filesystem implementations
-
- Xenix FS Doug Evans <dje@cygnus.com> June 1992
- SystemV FS Paul B. Monday <pmonday@eecs.wsu.edu> March-June 1993
- Coherent FS B. Haible <haible@ma2s2.mathematik.uni-karlsruhe.de> June 1993
-
-and was merged together in July 1993.
-
-These filesystems are rather similar. Here is a comparison with Minix FS:
-
-* Linux fdisk reports on partitions
- - Minix FS 0x81 Linux/Minix
- - Xenix FS ??
- - SystemV FS ??
- - Coherent FS 0x08 AIX bootable
-
-* Size of a block or zone (data allocation unit on disk)
- - Minix FS 1024
- - Xenix FS 1024 (also 512 ??)
- - SystemV FS 1024 (also 512 and 2048)
- - Coherent FS 512
-
-* General layout: all have one boot block, one super block and
- separate areas for inodes and for directories/data.
- On SystemV Release 2 FS (e.g. Microport) the first track is reserved and
- all the block numbers (including the super block) are offset by one track.
-
-* Byte ordering of "short" (16 bit entities) on disk:
- - Minix FS little endian 0 1
- - Xenix FS little endian 0 1
- - SystemV FS little endian 0 1
- - Coherent FS little endian 0 1
- Of course, this affects only the file system, not the data of files on it!
-
-* Byte ordering of "long" (32 bit entities) on disk:
- - Minix FS little endian 0 1 2 3
- - Xenix FS little endian 0 1 2 3
- - SystemV FS little endian 0 1 2 3
- - Coherent FS PDP-11 2 3 0 1
- Of course, this affects only the file system, not the data of files on it!
-
-* Inode on disk: "short", 0 means non-existent, the root dir ino is:
- - Minix FS 1
- - Xenix FS, SystemV FS, Coherent FS 2
-
-* Maximum number of hard links to a file:
- - Minix FS 250
- - Xenix FS ??
- - SystemV FS ??
- - Coherent FS >=10000
-
-* Free inode management:
- - Minix FS a bitmap
- - Xenix FS, SystemV FS, Coherent FS
- There is a cache of a certain number of free inodes in the super-block.
- When it is exhausted, new free inodes are found using a linear search.
-
-* Free block management:
- - Minix FS a bitmap
- - Xenix FS, SystemV FS, Coherent FS
- Free blocks are organized in a "free list". Maybe a misleading term,
- since it is not true that every free block contains a pointer to
- the next free block. Rather, the free blocks are organized in chunks
- of limited size, and every now and then a free block contains pointers
- to the free blocks pertaining to the next chunk; the first of these
- contains pointers and so on. The list terminates with a "block number"
- 0 on Xenix FS and SystemV FS, with a block zeroed out on Coherent FS.
-
-* Super-block location:
- - Minix FS block 1 = bytes 1024..2047
- - Xenix FS block 1 = bytes 1024..2047
- - SystemV FS bytes 512..1023
- - Coherent FS block 1 = bytes 512..1023
-
-* Super-block layout:
- - Minix FS
- unsigned short s_ninodes;
- unsigned short s_nzones;
- unsigned short s_imap_blocks;
- unsigned short s_zmap_blocks;
- unsigned short s_firstdatazone;
- unsigned short s_log_zone_size;
- unsigned long s_max_size;
- unsigned short s_magic;
- - Xenix FS, SystemV FS, Coherent FS
- unsigned short s_firstdatazone;
- unsigned long s_nzones;
- unsigned short s_fzone_count;
- unsigned long s_fzones[NICFREE];
- unsigned short s_finode_count;
- unsigned short s_finodes[NICINOD];
- char s_flock;
- char s_ilock;
- char s_modified;
- char s_rdonly;
- unsigned long s_time;
- short s_dinfo[4]; -- SystemV FS only
- unsigned long s_free_zones;
- unsigned short s_free_inodes;
- short s_dinfo[4]; -- Xenix FS only
- unsigned short s_interleave_m,s_interleave_n; -- Coherent FS only
- char s_fname[6];
- char s_fpack[6];
- then they differ considerably:
- Xenix FS
- char s_clean;
- char s_fill[371];
- long s_magic;
- long s_type;
- SystemV FS
- long s_fill[12 or 14];
- long s_state;
- long s_magic;
- long s_type;
- Coherent FS
- unsigned long s_unique;
- Note that Coherent FS has no magic.
-
-* Inode layout:
- - Minix FS
- unsigned short i_mode;
- unsigned short i_uid;
- unsigned long i_size;
- unsigned long i_time;
- unsigned char i_gid;
- unsigned char i_nlinks;
- unsigned short i_zone[7+1+1];
- - Xenix FS, SystemV FS, Coherent FS
- unsigned short i_mode;
- unsigned short i_nlink;
- unsigned short i_uid;
- unsigned short i_gid;
- unsigned long i_size;
- unsigned char i_zone[3*(10+1+1+1)];
- unsigned long i_atime;
- unsigned long i_mtime;
- unsigned long i_ctime;
-
-* Regular file data blocks are organized as
- - Minix FS
- 7 direct blocks
- 1 indirect block (pointers to blocks)
- 1 double-indirect block (pointer to pointers to blocks)
- - Xenix FS, SystemV FS, Coherent FS
- 10 direct blocks
- 1 indirect block (pointers to blocks)
- 1 double-indirect block (pointer to pointers to blocks)
- 1 triple-indirect block (pointer to pointers to pointers to blocks)
-
-* Inode size, inodes per block
- - Minix FS 32 32
- - Xenix FS 64 16
- - SystemV FS 64 16
- - Coherent FS 64 8
-
-* Directory entry on disk
- - Minix FS
- unsigned short inode;
- char name[14/30];
- - Xenix FS, SystemV FS, Coherent FS
- unsigned short inode;
- char name[14];
-
-* Dir entry size, dir entries per block
- - Minix FS 16/32 64/32
- - Xenix FS 16 64
- - SystemV FS 16 64
- - Coherent FS 16 32
-
-* How to implement symbolic links such that the host fsck doesn't scream:
- - Minix FS normal
- - Xenix FS kludge: as regular files with chmod 1000
- - SystemV FS ??
- - Coherent FS kludge: as regular files with chmod 1000
-
-
-Notation: We often speak of a "block" but mean a zone (the allocation unit)
-and not the disk driver's notion of "block".
-
-
-Bruno Haible <haible@ma2s2.mathematik.uni-karlsruhe.de>
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff