diff options
| author | Adrian Bunk <bunk@stusta.de> | 2006-12-06 23:40:01 -0500 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.osdl.org> | 2006-12-07 11:39:44 -0500 |
| commit | 3982cd99c30285ebc71d405cd8530a3dfb7265de (patch) | |
| tree | 288eb99e0c77acb7c58f1820d5579ce161e6a88e | |
| parent | f1a60dbf68061e5a5364cbc723786b355637ffd3 (diff) | |
[PATCH] fs/sysv/: doc cleanup
Remove two different changelog files from fs/sysv/ and merges the INTRO
file into Documentation/filesystems/sysv-fs.txt
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | Documentation/filesystems/sysv-fs.txt | 177 | ||||
| -rw-r--r-- | fs/sysv/CHANGES | 60 | ||||
| -rw-r--r-- | fs/sysv/ChangeLog | 106 | ||||
| -rw-r--r-- | fs/sysv/INTRO | 182 |
4 files changed, 168 insertions, 357 deletions
diff --git a/Documentation/filesystems/sysv-fs.txt b/Documentation/filesystems/sysv-fs.txt index d81722418010..253b50d1328e 100644 --- a/Documentation/filesystems/sysv-fs.txt +++ b/Documentation/filesystems/sysv-fs.txt | |||
| @@ -1,11 +1,8 @@ | |||
| 1 | This is the implementation of the SystemV/Coherent filesystem for Linux. | ||
| 2 | It implements all of | 1 | It implements all of |
| 3 | - Xenix FS, | 2 | - Xenix FS, |
| 4 | - SystemV/386 FS, | 3 | - SystemV/386 FS, |
| 5 | - Coherent FS. | 4 | - Coherent FS. |
| 6 | 5 | ||
| 7 | This is version beta 4. | ||
| 8 | |||
| 9 | To install: | 6 | To install: |
| 10 | * Answer the 'System V and Coherent filesystem support' question with 'y' | 7 | * Answer the 'System V and Coherent filesystem support' question with 'y' |
| 11 | when configuring the kernel. | 8 | when configuring the kernel. |
| @@ -28,11 +25,173 @@ Bugs in the present implementation: | |||
| 28 | for this FS on hard disk yet. | 25 | for this FS on hard disk yet. |
| 29 | 26 | ||
| 30 | 27 | ||
| 31 | Please report any bugs and suggestions to | 28 | These filesystems are rather similar. Here is a comparison with Minix FS: |
| 32 | Bruno Haible <haible@ma2s2.mathematik.uni-karlsruhe.de> | 29 | |
| 33 | Pascal Haible <haible@izfm.uni-stuttgart.de> | 30 | * Linux fdisk reports on partitions |
| 34 | Krzysztof G. Baranowski <kgb@manjak.knm.org.pl> | 31 | - Minix FS 0x81 Linux/Minix |
| 32 | - Xenix FS ?? | ||
| 33 | - SystemV FS ?? | ||
| 34 | - Coherent FS 0x08 AIX bootable | ||
| 35 | |||
| 36 | * Size of a block or zone (data allocation unit on disk) | ||
| 37 | - Minix FS 1024 | ||
| 38 | - Xenix FS 1024 (also 512 ??) | ||
| 39 | - SystemV FS 1024 (also 512 and 2048) | ||
| 40 | - Coherent FS 512 | ||
| 41 | |||
| 42 | * General layout: all have one boot block, one super block and | ||
| 43 | separate areas for inodes and for directories/data. | ||
| 44 | On SystemV Release 2 FS (e.g. Microport) the first track is reserved and | ||
| 45 | all the block numbers (including the super block) are offset by one track. | ||
| 46 | |||
| 47 | * Byte ordering of "short" (16 bit entities) on disk: | ||
| 48 | - Minix FS little endian 0 1 | ||
| 49 | - Xenix FS little endian 0 1 | ||
| 50 | - SystemV FS little endian 0 1 | ||
| 51 | - Coherent FS little endian 0 1 | ||
| 52 | Of course, this affects only the file system, not the data of files on it! | ||
| 53 | |||
| 54 | * Byte ordering of "long" (32 bit entities) on disk: | ||
| 55 | - Minix FS little endian 0 1 2 3 | ||
| 56 | - Xenix FS little endian 0 1 2 3 | ||
| 57 | - SystemV FS little endian 0 1 2 3 | ||
| 58 | - Coherent FS PDP-11 2 3 0 1 | ||
| 59 | Of course, this affects only the file system, not the data of files on it! | ||
| 60 | |||
| 61 | * Inode on disk: "short", 0 means non-existent, the root dir ino is: | ||
| 62 | - Minix FS 1 | ||
| 63 | - Xenix FS, SystemV FS, Coherent FS 2 | ||
| 64 | |||
| 65 | * Maximum number of hard links to a file: | ||
| 66 | - Minix FS 250 | ||
| 67 | - Xenix FS ?? | ||
| 68 | - SystemV FS ?? | ||
| 69 | - Coherent FS >=10000 | ||
| 70 | |||
| 71 | * Free inode management: | ||
| 72 | - Minix FS a bitmap | ||
| 73 | - Xenix FS, SystemV FS, Coherent FS | ||
| 74 | There is a cache of a certain number of free inodes in the super-block. | ||
| 75 | When it is exhausted, new free inodes are found using a linear search. | ||
| 76 | |||
| 77 | * Free block management: | ||
| 78 | - Minix FS a bitmap | ||
| 79 | - Xenix FS, SystemV FS, Coherent FS | ||
| 80 | Free blocks are organized in a "free list". Maybe a misleading term, | ||
| 81 | since it is not true that every free block contains a pointer to | ||
| 82 | the next free block. Rather, the free blocks are organized in chunks | ||
| 83 | of limited size, and every now and then a free block contains pointers | ||
| 84 | to the free blocks pertaining to the next chunk; the first of these | ||
| 85 | contains pointers and so on. The list terminates with a "block number" | ||
| 86 | 0 on Xenix FS and SystemV FS, with a block zeroed out on Coherent FS. | ||
| 87 | |||
| 88 | * Super-block location: | ||
| 89 | - Minix FS block 1 = bytes 1024..2047 | ||
| 90 | - Xenix FS block 1 = bytes 1024..2047 | ||
| 91 | - SystemV FS bytes 512..1023 | ||
| 92 | - Coherent FS block 1 = bytes 512..1023 | ||
| 93 | |||
| 94 | * Super-block layout: | ||
| 95 | - Minix FS | ||
| 96 | unsigned short s_ninodes; | ||
| 97 | unsigned short s_nzones; | ||
| 98 | unsigned short s_imap_blocks; | ||
| 99 | unsigned short s_zmap_blocks; | ||
| 100 | unsigned short s_firstdatazone; | ||
| 101 | unsigned short s_log_zone_size; | ||
| 102 | unsigned long s_max_size; | ||
| 103 | unsigned short s_magic; | ||
| 104 | - Xenix FS, SystemV FS, Coherent FS | ||
| 105 | unsigned short s_firstdatazone; | ||
| 106 | unsigned long s_nzones; | ||
| 107 | unsigned short s_fzone_count; | ||
| 108 | unsigned long s_fzones[NICFREE]; | ||
| 109 | unsigned short s_finode_count; | ||
| 110 | unsigned short s_finodes[NICINOD]; | ||
| 111 | char s_flock; | ||
| 112 | char s_ilock; | ||
| 113 | char s_modified; | ||
| 114 | char s_rdonly; | ||
| 115 | unsigned long s_time; | ||
| 116 | short s_dinfo[4]; -- SystemV FS only | ||
| 117 | unsigned long s_free_zones; | ||
| 118 | unsigned short s_free_inodes; | ||
| 119 | short s_dinfo[4]; -- Xenix FS only | ||
| 120 | unsigned short s_interleave_m,s_interleave_n; -- Coherent FS only | ||
| 121 | char s_fname[6]; | ||
| 122 | char s_fpack[6]; | ||
| 123 | then they differ considerably: | ||
| 124 | Xenix FS | ||
| 125 | char s_clean; | ||
| 126 | char s_fill[371]; | ||
| 127 | long s_magic; | ||
| 128 | long s_type; | ||
| 129 | SystemV FS | ||
| 130 | long s_fill[12 or 14]; | ||
| 131 | long s_state; | ||
| 132 | long s_magic; | ||
| 133 | long s_type; | ||
| 134 | Coherent FS | ||
| 135 | unsigned long s_unique; | ||
| 136 | Note that Coherent FS has no magic. | ||
| 137 | |||
| 138 | * Inode layout: | ||
| 139 | - Minix FS | ||
| 140 | unsigned short i_mode; | ||
| 141 | unsigned short i_uid; | ||
| 142 | unsigned long i_size; | ||
| 143 | unsigned long i_time; | ||
| 144 | unsigned char i_gid; | ||
| 145 | unsigned char i_nlinks; | ||
| 146 | unsigned short i_zone[7+1+1]; | ||
| 147 | - Xenix FS, SystemV FS, Coherent FS | ||
| 148 | unsigned short i_mode; | ||
| 149 | unsigned short i_nlink; | ||
| 150 | unsigned short i_uid; | ||
| 151 | unsigned short i_gid; | ||
| 152 | unsigned long i_size; | ||
| 153 | unsigned char i_zone[3*(10+1+1+1)]; | ||
| 154 | unsigned long i_atime; | ||
| 155 | unsigned long i_mtime; | ||
| 156 | unsigned long i_ctime; | ||
| 157 | |||
| 158 | * Regular file data blocks are organized as | ||
| 159 | - Minix FS | ||
| 160 | 7 direct blocks | ||
| 161 | 1 indirect block (pointers to blocks) | ||
| 162 | 1 double-indirect block (pointer to pointers to blocks) | ||
| 163 | - Xenix FS, SystemV FS, Coherent FS | ||
| 164 | 10 direct blocks | ||
| 165 | 1 indirect block (pointers to blocks) | ||
| 166 | 1 double-indirect block (pointer to pointers to blocks) | ||
| 167 | 1 triple-indirect block (pointer to pointers to pointers to blocks) | ||
| 168 | |||
| 169 | * Inode size, inodes per block | ||
| 170 | - Minix FS 32 32 | ||
| 171 | - Xenix FS 64 16 | ||
| 172 | - SystemV FS 64 16 | ||
| 173 | - Coherent FS 64 8 | ||
| 174 | |||
| 175 | * Directory entry on disk | ||
| 176 | - Minix FS | ||
| 177 | unsigned short inode; | ||
| 178 | char name[14/30]; | ||
| 179 | - Xenix FS, SystemV FS, Coherent FS | ||
| 180 | unsigned short inode; | ||
| 181 | char name[14]; | ||
| 182 | |||
| 183 | * Dir entry size, dir entries per block | ||
| 184 | - Minix FS 16/32 64/32 | ||
| 185 | - Xenix FS 16 64 | ||
| 186 | - SystemV FS 16 64 | ||
| 187 | - Coherent FS 16 32 | ||
| 188 | |||
| 189 | * How to implement symbolic links such that the host fsck doesn't scream: | ||
| 190 | - Minix FS normal | ||
| 191 | - Xenix FS kludge: as regular files with chmod 1000 | ||
| 192 | - SystemV FS ?? | ||
| 193 | - Coherent FS kludge: as regular files with chmod 1000 | ||
| 35 | 194 | ||
| 36 | Bruno Haible | ||
| 37 | <haible@ma2s2.mathematik.uni-karlsruhe.de> | ||
| 38 | 195 | ||
| 196 | Notation: We often speak of a "block" but mean a zone (the allocation unit) | ||
| 197 | and not the disk driver's notion of "block". | ||
diff --git a/fs/sysv/CHANGES b/fs/sysv/CHANGES deleted file mode 100644 index 66ea6e92be66..000000000000 --- a/fs/sysv/CHANGES +++ /dev/null | |||
| @@ -1,60 +0,0 @@ | |||
| 1 | Mon, 15 Dec 1997 Krzysztof G. Baranowski <kgb@manjak.knm.org.pl> | ||
| 2 | * namei.c: struct sysv_dir_inode_operations updated to use dentries. | ||
| 3 | |||
| 4 | Fri, 23 Jan 1998 Krzysztof G. Baranowski <kgb@manjak.knm.org.pl> | ||
| 5 | * inode.c: corrected 1 track offset setting (in sb->sv_block_base). | ||
| 6 | Originally it was overridden (by setting to zero) | ||
| 7 | in detected_[xenix,sysv4,sysv2,coherent]. Thanks | ||
| 8 | to Andrzej Krzysztofowicz <ankry@mif.pg.gda.pl> | ||
| 9 | for identifying the problem. | ||
| 10 | |||
| 11 | Tue, 27 Jan 1998 Krzysztof G. Baranowski <kgb@manjak.knm.org.pl> | ||
| 12 | * inode.c: added 2048-byte block support to SystemV FS. | ||
| 13 | Merged detected_bs[512,1024,2048]() into one function: | ||
| 14 | void detected_bs (u_char type, struct super_block *sb). | ||
| 15 | Thanks to Andrzej Krzysztofowicz <ankry@mif.pg.gda.pl> | ||
| 16 | for the patch. | ||
| 17 | |||
| 18 | Wed, 4 Feb 1998 Krzysztof G. Baranowski <kgb@manjak.knm.org.pl> | ||
| 19 | * namei.c: removed static subdir(); is_subdir() from dcache.c | ||
| 20 | is used instead. Cosmetic changes. | ||
| 21 | |||
| 22 | Thu, 3 Dec 1998 Al Viro (viro@parcelfarce.linux.theplanet.co.uk) | ||
| 23 | * namei.c (sysv_rmdir): | ||
| 24 | Bugectomy: old check for victim being busy | ||
| 25 | (inode->i_count) wasn't replaced (with checking | ||
| 26 | dentry->d_count) and escaped Linus in the last round | ||
| 27 | of changes. Shot and buried. | ||
| 28 | |||
| 29 | Wed, 9 Dec 1998 AV | ||
| 30 | * namei.c (do_sysv_rename): | ||
| 31 | Fixed incorrect check for other owners + race. | ||
| 32 | Removed checks that went to VFS. | ||
| 33 | * namei.c (sysv_unlink): | ||
| 34 | Removed checks that went to VFS. | ||
| 35 | |||
| 36 | Thu, 10 Dec 1998 AV | ||
| 37 | * namei.c (do_mknod): | ||
| 38 | Removed dead code - mknod is never asked to | ||
| 39 | create a symlink or directory. Incidentially, | ||
| 40 | it wouldn't do it right if it would be called. | ||
| 41 | |||
| 42 | Sat, 26 Dec 1998 KGB | ||
| 43 | * inode.c (detect_sysv4): | ||
| 44 | Added detection of expanded s_type field (0x10, | ||
| 45 | 0x20 and 0x30). Forced read-only access in this case. | ||
| 46 | |||
| 47 | Sun, 21 Mar 1999 AV | ||
| 48 | * namei.c (sysv_link): | ||
| 49 | Fixed i_count usage that resulted in dcache corruption. | ||
| 50 | * inode.c: | ||
| 51 | Filled ->delete_inode() method with sysv_delete_inode(). | ||
| 52 | sysv_put_inode() is gone, as it tried to do ->delete_ | ||
| 53 | _inode()'s job. | ||
| 54 | * ialloc.c: (sysv_free_inode): | ||
| 55 | Fixed race. | ||
| 56 | |||
| 57 | Sun, 30 Apr 1999 AV | ||
| 58 | * namei.c (sysv_mknod): | ||
| 59 | Removed dead code (S_IFREG case is now passed to | ||
| 60 | ->create() by VFS). | ||
diff --git a/fs/sysv/ChangeLog b/fs/sysv/ChangeLog deleted file mode 100644 index f403f8b91b80..000000000000 --- a/fs/sysv/ChangeLog +++ /dev/null | |||
| @@ -1,106 +0,0 @@ | |||
| 1 | Thu Feb 14 2002 Andrew Morton <akpm@zip.com.au> | ||
| 2 | |||
| 3 | * dir_commit_chunk(): call writeout_one_page() as well as | ||
| 4 | waitfor_one_page() for IS_SYNC directories, so that we | ||
| 5 | actually do sync the directory. (forward-port from 2.4). | ||
| 6 | |||
| 7 | Thu Feb 7 2002 Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk> | ||
| 8 | |||
| 9 | * super.c: switched to ->get_sb() | ||
| 10 | * ChangeLog: fixed dates ;-) | ||
| 11 | |||
| 12 | 2002-01-24 David S. Miller <davem@redhat.com> | ||
| 13 | |||
| 14 | * inode.c: Include linux/init.h | ||
| 15 | |||
| 16 | Mon Jan 21 2002 Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk> | ||
| 17 | * ialloc.c (sysv_new_inode): zero SYSV_I(inode)->i_data out. | ||
| 18 | * i_vnode renamed to vfs_inode. Sorry, but let's keep that | ||
| 19 | consistent. | ||
| 20 | |||
| 21 | Sat Jan 19 2002 Christoph Hellwig <hch@infradead.org> | ||
| 22 | |||
| 23 | * include/linux/sysv_fs.h (SYSV_I): Get fs-private inode data using | ||
| 24 | list_entry() instead of inode->u. | ||
| 25 | * include/linux/sysv_fs_i.h: Add 'struct inode i_vnode' field to | ||
| 26 | sysv_inode_info structure. | ||
| 27 | * inode.c: Include <linux/slab.h>, implement alloc_inode/destroy_inode | ||
| 28 | sop methods, add infrastructure for per-fs inode slab cache. | ||
| 29 | * super.c (init_sysv_fs): Initialize inode cache, recover properly | ||
| 30 | in the case of failed register_filesystem for V7. | ||
| 31 | (exit_sysv_fs): Destroy inode cache. | ||
| 32 | |||
| 33 | Sat Jan 19 2002 Christoph Hellwig <hch@infradead.org> | ||
| 34 | |||
| 35 | * include/linux/sysv_fs.h: Include <linux/sysv_fs_i.h>, declare SYSV_I(). | ||
| 36 | * dir.c (sysv_find_entry): Use SYSV_I() instead of ->u.sysv_i to | ||
| 37 | access fs-private inode data. | ||
| 38 | * ialloc.c (sysv_new_inode): Likewise. | ||
| 39 | * inode.c (sysv_read_inode): Likewise. | ||
| 40 | (sysv_update_inode): Likewise. | ||
| 41 | * itree.c (get_branch): Likewise. | ||
| 42 | (sysv_truncate): Likewise. | ||
| 43 | * symlink.c (sysv_readlink): Likewise. | ||
| 44 | (sysv_follow_link): Likewise. | ||
| 45 | |||
| 46 | Fri Jan 4 2002 Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk> | ||
| 47 | |||
| 48 | * ialloc.c (sysv_free_inode): Use sb->s_id instead of bdevname(). | ||
| 49 | * inode.c (sysv_read_inode): Likewise. | ||
| 50 | (sysv_update_inode): Likewise. | ||
| 51 | (sysv_sync_inode): Likewise. | ||
| 52 | * super.c (detect_sysv): Likewise. | ||
| 53 | (complete_read_super): Likewise. | ||
| 54 | (sysv_read_super): Likewise. | ||
| 55 | (v7_read_super): Likewise. | ||
| 56 | |||
| 57 | Sun Dec 30 2001 Manfred Spraul <manfred@colorfullife.com> | ||
| 58 | |||
| 59 | * dir.c (dir_commit_chunk): Do not set dir->i_version. | ||
| 60 | (sysv_readdir): Likewise. | ||
| 61 | |||
| 62 | Thu Dec 27 2001 Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk> | ||
| 63 | |||
| 64 | * itree.c (get_block): Use map_bh() to fill out bh_result. | ||
| 65 | |||
| 66 | Tue Dec 25 2001 Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk> | ||
| 67 | |||
| 68 | * super.c (sysv_read_super): Use sb_set_blocksize() to set blocksize. | ||
| 69 | (v7_read_super): Likewise. | ||
| 70 | |||
| 71 | Tue Nov 27 2001 Alexander Viro <viro@parcelfarce.linux.theplanet.co.uk> | ||
| 72 | |||
| 73 | * itree.c (get_block): Change type for iblock argument to sector_t. | ||
| 74 | * super.c (sysv_read_super): Set s_blocksize early. | ||
| 75 | (v7_read_super): Likewise. | ||
| 76 | * balloc.c (sysv_new_block): Use sb_bread(). instead of bread(). | ||
| 77 | (sysv_count_free_blocks): Likewise. | ||
| 78 | * ialloc.c (sysv_raw_inode): Likewise. | ||
| 79 | * itree.c (get_branch): Likewise. | ||
| 80 | (free_branches): Likewise. | ||
| 81 | * super.c (sysv_read_super): Likewise. | ||
| 82 | (v7_read_super): Likewise. | ||
| 83 | |||
| 84 | Sat Dec 15 2001 Christoph Hellwig <hch@infradead.org> | ||
| 85 | |||
| 86 | * inode.c (sysv_read_inode): Mark inode as bad in case of failure. | ||
| 87 | * super.c (complete_read_super): Check for bad root inode. | ||
| 88 | |||
| 89 | Wed Nov 21 2001 Andrew Morton <andrewm@uow.edu.au> | ||
| 90 | |||
| 91 | * file.c (sysv_sync_file): Call fsync_inode_data_buffers. | ||
| 92 | |||
| 93 | Fri Oct 26 2001 Christoph Hellwig <hch@infradead.org> | ||
| 94 | |||
| 95 | * dir.c, ialloc.c, namei.c, include/linux/sysv_fs_i.h: | ||
| 96 | Implement per-Inode lookup offset cache. | ||
| 97 | Modelled after Ted's ext2 patch. | ||
| 98 | |||
| 99 | Fri Oct 26 2001 Christoph Hellwig <hch@infradead.org> | ||
| 100 | |||
| 101 | * inode.c, super.c, include/linux/sysv_fs.h, | ||
| 102 | include/linux/sysv_fs_sb.h: | ||
| 103 | Remove symlink faking. Noone really wants to use these as | ||
| 104 | linux filesystems and native OSes don't support it anyway. | ||
| 105 | |||
| 106 | |||
diff --git a/fs/sysv/INTRO b/fs/sysv/INTRO deleted file mode 100644 index de4e4d17cac6..000000000000 --- a/fs/sysv/INTRO +++ /dev/null | |||
| @@ -1,182 +0,0 @@ | |||
| 1 | This is the implementation of the SystemV/Coherent filesystem for Linux. | ||
| 2 | It grew out of separate filesystem implementations | ||
| 3 | |||
| 4 | Xenix FS Doug Evans <dje@cygnus.com> June 1992 | ||
| 5 | SystemV FS Paul B. Monday <pmonday@eecs.wsu.edu> March-June 1993 | ||
| 6 | Coherent FS B. Haible <haible@ma2s2.mathematik.uni-karlsruhe.de> June 1993 | ||
| 7 | |||
| 8 | and was merged together in July 1993. | ||
| 9 | |||
| 10 | These filesystems are rather similar. Here is a comparison with Minix FS: | ||
| 11 | |||
| 12 | * Linux fdisk reports on partitions | ||
| 13 | - Minix FS 0x81 Linux/Minix | ||
| 14 | - Xenix FS ?? | ||
| 15 | - SystemV FS ?? | ||
| 16 | - Coherent FS 0x08 AIX bootable | ||
| 17 | |||
| 18 | * Size of a block or zone (data allocation unit on disk) | ||
| 19 | - Minix FS 1024 | ||
| 20 | - Xenix FS 1024 (also 512 ??) | ||
| 21 | - SystemV FS 1024 (also 512 and 2048) | ||
| 22 | - Coherent FS 512 | ||
| 23 | |||
| 24 | * General layout: all have one boot block, one super block and | ||
| 25 | separate areas for inodes and for directories/data. | ||
| 26 | On SystemV Release 2 FS (e.g. Microport) the first track is reserved and | ||
| 27 | all the block numbers (including the super block) are offset by one track. | ||
| 28 | |||
| 29 | * Byte ordering of "short" (16 bit entities) on disk: | ||
| 30 | - Minix FS little endian 0 1 | ||
| 31 | - Xenix FS little endian 0 1 | ||
| 32 | - SystemV FS little endian 0 1 | ||
| 33 | - Coherent FS little endian 0 1 | ||
| 34 | Of course, this affects only the file system, not the data of files on it! | ||
| 35 | |||
| 36 | * Byte ordering of "long" (32 bit entities) on disk: | ||
| 37 | - Minix FS little endian 0 1 2 3 | ||
| 38 | - Xenix FS little endian 0 1 2 3 | ||
| 39 | - SystemV FS little endian 0 1 2 3 | ||
| 40 | - Coherent FS PDP-11 2 3 0 1 | ||
| 41 | Of course, this affects only the file system, not the data of files on it! | ||
| 42 | |||
| 43 | * Inode on disk: "short", 0 means non-existent, the root dir ino is: | ||
| 44 | - Minix FS 1 | ||
| 45 | - Xenix FS, SystemV FS, Coherent FS 2 | ||
| 46 | |||
| 47 | * Maximum number of hard links to a file: | ||
| 48 | - Minix FS 250 | ||
| 49 | - Xenix FS ?? | ||
| 50 | - SystemV FS ?? | ||
| 51 | - Coherent FS >=10000 | ||
| 52 | |||
| 53 | * Free inode management: | ||
| 54 | - Minix FS a bitmap | ||
| 55 | - Xenix FS, SystemV FS, Coherent FS | ||
| 56 | There is a cache of a certain number of free inodes in the super-block. | ||
| 57 | When it is exhausted, new free inodes are found using a linear search. | ||
| 58 | |||
| 59 | * Free block management: | ||
| 60 | - Minix FS a bitmap | ||
| 61 | - Xenix FS, SystemV FS, Coherent FS | ||
| 62 | Free blocks are organized in a "free list". Maybe a misleading term, | ||
| 63 | since it is not true that every free block contains a pointer to | ||
| 64 | the next free block. Rather, the free blocks are organized in chunks | ||
| 65 | of limited size, and every now and then a free block contains pointers | ||
| 66 | to the free blocks pertaining to the next chunk; the first of these | ||
| 67 | contains pointers and so on. The list terminates with a "block number" | ||
| 68 | 0 on Xenix FS and SystemV FS, with a block zeroed out on Coherent FS. | ||
| 69 | |||
| 70 | * Super-block location: | ||
| 71 | - Minix FS block 1 = bytes 1024..2047 | ||
| 72 | - Xenix FS block 1 = bytes 1024..2047 | ||
| 73 | - SystemV FS bytes 512..1023 | ||
| 74 | - Coherent FS block 1 = bytes 512..1023 | ||
| 75 | |||
| 76 | * Super-block layout: | ||
| 77 | - Minix FS | ||
| 78 | unsigned short s_ninodes; | ||
| 79 | unsigned short s_nzones; | ||
| 80 | unsigned short s_imap_blocks; | ||
| 81 | unsigned short s_zmap_blocks; | ||
| 82 | unsigned short s_firstdatazone; | ||
| 83 | unsigned short s_log_zone_size; | ||
| 84 | unsigned long s_max_size; | ||
| 85 | unsigned short s_magic; | ||
| 86 | - Xenix FS, SystemV FS, Coherent FS | ||
| 87 | unsigned short s_firstdatazone; | ||
| 88 | unsigned long s_nzones; | ||
| 89 | unsigned short s_fzone_count; | ||
| 90 | unsigned long s_fzones[NICFREE]; | ||
| 91 | unsigned short s_finode_count; | ||
| 92 | unsigned short s_finodes[NICINOD]; | ||
| 93 | char s_flock; | ||
| 94 | char s_ilock; | ||
| 95 | char s_modified; | ||
| 96 | char s_rdonly; | ||
| 97 | unsigned long s_time; | ||
| 98 | short s_dinfo[4]; -- SystemV FS only | ||
| 99 | unsigned long s_free_zones; | ||
| 100 | unsigned short s_free_inodes; | ||
| 101 | short s_dinfo[4]; -- Xenix FS only | ||
| 102 | unsigned short s_interleave_m,s_interleave_n; -- Coherent FS only | ||
| 103 | char s_fname[6]; | ||
| 104 | char s_fpack[6]; | ||
| 105 | then they differ considerably: | ||
| 106 | Xenix FS | ||
| 107 | char s_clean; | ||
| 108 | char s_fill[371]; | ||
| 109 | long s_magic; | ||
| 110 | long s_type; | ||
| 111 | SystemV FS | ||
| 112 | long s_fill[12 or 14]; | ||
| 113 | long s_state; | ||
| 114 | long s_magic; | ||
| 115 | long s_type; | ||
| 116 | Coherent FS | ||
| 117 | unsigned long s_unique; | ||
| 118 | Note that Coherent FS has no magic. | ||
| 119 | |||
| 120 | * Inode layout: | ||
| 121 | - Minix FS | ||
| 122 | unsigned short i_mode; | ||
| 123 | unsigned short i_uid; | ||
| 124 | unsigned long i_size; | ||
| 125 | unsigned long i_time; | ||
| 126 | unsigned char i_gid; | ||
| 127 | unsigned char i_nlinks; | ||
| 128 | unsigned short i_zone[7+1+1]; | ||
| 129 | - Xenix FS, SystemV FS, Coherent FS | ||
| 130 | unsigned short i_mode; | ||
| 131 | unsigned short i_nlink; | ||
| 132 | unsigned short i_uid; | ||
| 133 | unsigned short i_gid; | ||
| 134 | unsigned long i_size; | ||
| 135 | unsigned char i_zone[3*(10+1+1+1)]; | ||
| 136 | unsigned long i_atime; | ||
| 137 | unsigned long i_mtime; | ||
| 138 | unsigned long i_ctime; | ||
| 139 | |||
| 140 | * Regular file data blocks are organized as | ||
| 141 | - Minix FS | ||
| 142 | 7 direct blocks | ||
| 143 | 1 indirect block (pointers to blocks) | ||
| 144 | 1 double-indirect block (pointer to pointers to blocks) | ||
| 145 | - Xenix FS, SystemV FS, Coherent FS | ||
| 146 | 10 direct blocks | ||
| 147 | 1 indirect block (pointers to blocks) | ||
| 148 | 1 double-indirect block (pointer to pointers to blocks) | ||
| 149 | 1 triple-indirect block (pointer to pointers to pointers to blocks) | ||
| 150 | |||
| 151 | * Inode size, inodes per block | ||
| 152 | - Minix FS 32 32 | ||
| 153 | - Xenix FS 64 16 | ||
| 154 | - SystemV FS 64 16 | ||
| 155 | - Coherent FS 64 8 | ||
| 156 | |||
| 157 | * Directory entry on disk | ||
| 158 | - Minix FS | ||
| 159 | unsigned short inode; | ||
| 160 | char name[14/30]; | ||
| 161 | - Xenix FS, SystemV FS, Coherent FS | ||
| 162 | unsigned short inode; | ||
| 163 | char name[14]; | ||
| 164 | |||
| 165 | * Dir entry size, dir entries per block | ||
| 166 | - Minix FS 16/32 64/32 | ||
| 167 | - Xenix FS 16 64 | ||
| 168 | - SystemV FS 16 64 | ||
| 169 | - Coherent FS 16 32 | ||
| 170 | |||
| 171 | * How to implement symbolic links such that the host fsck doesn't scream: | ||
| 172 | - Minix FS normal | ||
| 173 | - Xenix FS kludge: as regular files with chmod 1000 | ||
| 174 | - SystemV FS ?? | ||
| 175 | - Coherent FS kludge: as regular files with chmod 1000 | ||
| 176 | |||
| 177 | |||
| 178 | Notation: We often speak of a "block" but mean a zone (the allocation unit) | ||
| 179 | and not the disk driver's notion of "block". | ||
| 180 | |||
| 181 | |||
| 182 | Bruno Haible <haible@ma2s2.mathematik.uni-karlsruhe.de> | ||
