1.. SPDX-License-Identifier: GPL-2.0 2 3==================== 4Read/Write HPFS 2.09 5==================== 6 71998-2004, Mikulas Patocka 8 9:email: mikulas@artax.karlin.mff.cuni.cz 10:homepage: https://artax.karlin.mff.cuni.cz/~mikulas/vyplody/hpfs/index-e.cgi 11 12Credits 13======= 14Chris Smith, 1993, original read-only HPFS, some code and hpfs structures file 15 is taken from it 16 17Jacques Gelinas, MSDos mmap, Inspired by fs/nfs/mmap.c (Jon Tombs 15 Aug 1993) 18 19Werner Almesberger, 1992, 1993, MSDos option parser & CR/LF conversion 20 21Mount options 22 23uid=xxx,gid=xxx,umask=xxx (default uid=gid=0 umask=default_system_umask) 24 Set owner/group/mode for files that do not have it specified in extended 25 attributes. Mode is inverted umask - for example umask 027 gives owner 26 all permission, group read permission and anybody else no access. Note 27 that for files mode is anded with 0666. If you want files to have 'x' 28 rights, you must use extended attributes. 29case=lower,asis (default asis) 30 File name lowercasing in readdir. 31conv=binary,text,auto (default binary) 32 CR/LF -> LF conversion, if auto, decision is made according to extension 33 - there is a list of text extensions (I thing it's better to not convert 34 text file than to damage binary file). If you want to change that list, 35 change it in the source. Original readonly HPFS contained some strange 36 heuristic algorithm that I removed. I thing it's danger to let the 37 computer decide whether file is text or binary. For example, DJGPP 38 binaries contain small text message at the beginning and they could be 39 misidentified and damaged under some circumstances. 40check=none,normal,strict (default normal) 41 Check level. Selecting none will cause only little speedup and big 42 danger. I tried to write it so that it won't crash if check=normal on 43 corrupted filesystems. check=strict means many superfluous checks - 44 used for debugging (for example it checks if file is allocated in 45 bitmaps when accessing it). 46errors=continue,remount-ro,panic (default remount-ro) 47 Behaviour when filesystem errors found. 48chkdsk=no,errors,always (default errors) 49 When to mark filesystem dirty so that OS/2 checks it. 50eas=no,ro,rw (default rw) 51 What to do with extended attributes. 'no' - ignore them and use always 52 values specified in uid/gid/mode options. 'ro' - read extended 53 attributes but do not create them. 'rw' - create extended attributes 54 when you use chmod/chown/chgrp/mknod/ln -s on the filesystem. 55timeshift=(-)nnn (default 0) 56 Shifts the time by nnn seconds. For example, if you see under linux 57 one hour more, than under os/2, use timeshift=-3600. 58 59 60File names 61========== 62 63As in OS/2, filenames are case insensitive. However, shell thinks that names 64are case sensitive, so for example when you create a file FOO, you can use 65'cat FOO', 'cat Foo', 'cat foo' or 'cat F*' but not 'cat f*'. Note, that you 66also won't be able to compile linux kernel (and maybe other things) on HPFS 67because kernel creates different files with names like bootsect.S and 68bootsect.s. When searching for file thats name has characters >= 128, codepages 69are used - see below. 70OS/2 ignores dots and spaces at the end of file name, so this driver does as 71well. If you create 'a. ...', the file 'a' will be created, but you can still 72access it under names 'a.', 'a..', 'a . . . ' etc. 73 74 75Extended attributes 76=================== 77 78On HPFS partitions, OS/2 can associate to each file a special information called 79extended attributes. Extended attributes are pairs of (key,value) where key is 80an ascii string identifying that attribute and value is any string of bytes of 81variable length. OS/2 stores window and icon positions and file types there. So 82why not use it for unix-specific info like file owner or access rights? This 83driver can do it. If you chown/chgrp/chmod on a hpfs partition, extended 84attributes with keys "UID", "GID" or "MODE" and 2-byte values are created. Only 85that extended attributes those value differs from defaults specified in mount 86options are created. Once created, the extended attributes are never deleted, 87they're just changed. It means that when your default uid=0 and you type 88something like 'chown luser file; chown root file' the file will contain 89extended attribute UID=0. And when you umount the fs and mount it again with 90uid=luser_uid, the file will be still owned by root! If you chmod file to 444, 91extended attribute "MODE" will not be set, this special case is done by setting 92read-only flag. When you mknod a block or char device, besides "MODE", the 93special 4-byte extended attribute "DEV" will be created containing the device 94number. Currently this driver cannot resize extended attributes - it means 95that if somebody (I don't know who?) has set "UID", "GID", "MODE" or "DEV" 96attributes with different sizes, they won't be rewritten and changing these 97values doesn't work. 98 99 100Symlinks 101======== 102 103You can do symlinks on HPFS partition, symlinks are achieved by setting extended 104attribute named "SYMLINK" with symlink value. Like on ext2, you can chown and 105chgrp symlinks but I don't know what is it good for. chmoding symlink results 106in chmoding file where symlink points. These symlinks are just for Linux use and 107incompatible with OS/2. OS/2 PmShell symlinks are not supported because they are 108stored in very crazy way. They tried to do it so that link changes when file is 109moved ... sometimes it works. But the link is partly stored in directory 110extended attributes and partly in OS2SYS.INI. I don't want (and don't know how) 111to analyze or change OS2SYS.INI. 112 113 114Codepages 115========= 116 117HPFS can contain several uppercasing tables for several codepages and each 118file has a pointer to codepage its name is in. However OS/2 was created in 119America where people don't care much about codepages and so multiple codepages 120support is quite buggy. I have Czech OS/2 working in codepage 852 on my disk. 121Once I booted English OS/2 working in cp 850 and I created a file on my 852 122partition. It marked file name codepage as 850 - good. But when I again booted 123Czech OS/2, the file was completely inaccessible under any name. It seems that 124OS/2 uppercases the search pattern with its system code page (852) and file 125name it's comparing to with its code page (850). These could never match. Is it 126really what IBM developers wanted? But problems continued. When I created in 127Czech OS/2 another file in that directory, that file was inaccessible too. OS/2 128probably uses different uppercasing method when searching where to place a file 129(note, that files in HPFS directory must be sorted) and when searching for 130a file. Finally when I opened this directory in PmShell, PmShell crashed (the 131funny thing was that, when rebooted, PmShell tried to reopen this directory 132again :-). chkdsk happily ignores these errors and only low-level disk 133modification saved me. Never mix different language versions of OS/2 on one 134system although HPFS was designed to allow that. 135OK, I could implement complex codepage support to this driver but I think it 136would cause more problems than benefit with such buggy implementation in OS/2. 137So this driver simply uses first codepage it finds for uppercasing and 138lowercasing no matter what's file codepage index. Usually all file names are in 139this codepage - if you don't try to do what I described above :-) 140 141 142Known bugs 143========== 144 145HPFS386 on OS/2 server is not supported. HPFS386 installed on normal OS/2 client 146should work. If you have OS/2 server, use only read-only mode. I don't know how 147to handle some HPFS386 structures like access control list or extended perm 148list, I don't know how to delete them when file is deleted and how to not 149overwrite them with extended attributes. Send me some info on these structures 150and I'll make it. However, this driver should detect presence of HPFS386 151structures, remount read-only and not destroy them (I hope). 152 153When there's not enough space for extended attributes, they will be truncated 154and no error is returned. 155 156OS/2 can't access files if the path is longer than about 256 chars but this 157driver allows you to do it. chkdsk ignores such errors. 158 159Sometimes you won't be able to delete some files on a very full filesystem 160(returning error ENOSPC). That's because file in non-leaf node in directory tree 161(one directory, if it's large, has dirents in tree on HPFS) must be replaced 162with another node when deleted. And that new file might have larger name than 163the old one so the new name doesn't fit in directory node (dnode). And that 164would result in directory tree splitting, that takes disk space. Workaround is 165to delete other files that are leaf (probability that the file is non-leaf is 166about 1/50) or to truncate file first to make some space. 167You encounter this problem only if you have many directories so that 168preallocated directory band is full i.e.:: 169 170 number_of_directories / size_of_filesystem_in_mb > 4. 171 172You can't delete open directories. 173 174You can't rename over directories (what is it good for?). 175 176Renaming files so that only case changes doesn't work. This driver supports it 177but vfs doesn't. Something like 'mv file FILE' won't work. 178 179All atimes and directory mtimes are not updated. That's because of performance 180reasons. If you extremely wish to update them, let me know, I'll write it (but 181it will be slow). 182 183When the system is out of memory and swap, it may slightly corrupt filesystem 184(lost files, unbalanced directories). (I guess all filesystem may do it). 185 186When compiled, you get warning: function declaration isn't a prototype. Does 187anybody know what does it mean? 188 189 190What does "unbalanced tree" message mean? 191========================================= 192 193Old versions of this driver created sometimes unbalanced dnode trees. OS/2 194chkdsk doesn't scream if the tree is unbalanced (and sometimes creates 195unbalanced trees too :-) but both HPFS and HPFS386 contain bug that it rarely 196crashes when the tree is not balanced. This driver handles unbalanced trees 197correctly and writes warning if it finds them. If you see this message, this is 198probably because of directories created with old version of this driver. 199Workaround is to move all files from that directory to another and then back 200again. Do it in Linux, not OS/2! If you see this message in directory that is 201whole created by this driver, it is BUG - let me know about it. 202 203 204Bugs in OS/2 205============ 206 207When you have two (or more) lost directories pointing each to other, chkdsk 208locks up when repairing filesystem. 209 210Sometimes (I think it's random) when you create a file with one-char name under 211OS/2, OS/2 marks it as 'long'. chkdsk then removes this flag saying "Minor fs 212error corrected". 213 214File names like "a .b" are marked as 'long' by OS/2 but chkdsk "corrects" it and 215marks them as short (and writes "minor fs error corrected"). This bug is not in 216HPFS386. 217 218Codepage bugs described above 219============================= 220 221If you don't install fixpacks, there are many, many more... 222 223 224History 225======= 226 227====== ========================================================================= 2280.90 First public release 2290.91 Fixed bug that caused shooting to memory when write_inode was called on 230 open inode (rarely happened) 2310.92 Fixed a little memory leak in freeing directory inodes 2320.93 Fixed bug that locked up the machine when there were too many filenames 233 with first 15 characters same 234 Fixed write_file to zero file when writing behind file end 2350.94 Fixed a little memory leak when trying to delete busy file or directory 2360.95 Fixed a bug that i_hpfs_parent_dir was not updated when moving files 2371.90 First version for 2.1.1xx kernels 2381.91 Fixed a bug that chk_sectors failed when sectors were at the end of disk 239 Fixed a race-condition when write_inode is called while deleting file 240 Fixed a bug that could possibly happen (with very low probability) when 241 using 0xff in filenames. 242 243 Rewritten locking to avoid race-conditions 244 245 Mount option 'eas' now works 246 247 Fsync no longer returns error 248 249 Files beginning with '.' are marked hidden 250 251 Remount support added 252 253 Alloc is not so slow when filesystem becomes full 254 255 Atimes are no more updated because it slows down operation 256 257 Code cleanup (removed all commented debug prints) 2581.92 Corrected a bug when sync was called just before closing file 2591.93 Modified, so that it works with kernels >= 2.1.131, I don't know if it 260 works with previous versions 261 262 Fixed a possible problem with disks > 64G (but I don't have one, so I can't 263 test it) 264 265 Fixed a file overflow at 2G 266 267 Added new option 'timeshift' 268 269 Changed behaviour on HPFS386: It is now possible to operate on HPFS386 in 270 read-only mode 271 272 Fixed a bug that slowed down alloc and prevented allocating 100% space 273 (this bug was not destructive) 2741.94 Added workaround for one bug in Linux 275 276 Fixed one buffer leak 277 278 Fixed some incompatibilities with large extended attributes (but it's still 279 not 100% ok, I have no info on it and OS/2 doesn't want to create them) 280 281 Rewritten allocation 282 283 Fixed a bug with i_blocks (du sometimes didn't display correct values) 284 285 Directories have no longer archive attribute set (some programs don't like 286 it) 287 288 Fixed a bug that it set badly one flag in large anode tree (it was not 289 destructive) 2901.95 Fixed one buffer leak, that could happen on corrupted filesystem 291 292 Fixed one bug in allocation in 1.94 2931.96 Added workaround for one bug in OS/2 (HPFS locked up, HPFS386 reported 294 error sometimes when opening directories in PMSHELL) 295 296 Fixed a possible bitmap race 297 298 Fixed possible problem on large disks 299 300 You can now delete open files 301 302 Fixed a nondestructive race in rename 3031.97 Support for HPFS v3 (on large partitions) 304 305 ZFixed a bug that it didn't allow creation of files > 128M 306 (it should be 2G) 3071.97.1 Changed names of global symbols 308 309 Fixed a bug when chmoding or chowning root directory 3101.98 Fixed a deadlock when using old_readdir 311 Better directory handling; workaround for "unbalanced tree" bug in OS/2 3121.99 Corrected a possible problem when there's not enough space while deleting 313 file 314 315 Now it tries to truncate the file if there's not enough space when 316 deleting 317 318 Removed a lot of redundant code 3192.00 Fixed a bug in rename (it was there since 1.96) 320 Better anti-fragmentation strategy 3212.01 Fixed problem with directory listing over NFS 322 323 Directory lseek now checks for proper parameters 324 325 Fixed race-condition in buffer code - it is in all filesystems in Linux; 326 when reading device (cat /dev/hda) while creating files on it, files 327 could be damaged 3282.02 Workaround for bug in breada in Linux. breada could cause accesses beyond 329 end of partition 3302.03 Char, block devices and pipes are correctly created 331 332 Fixed non-crashing race in unlink (Alexander Viro) 333 334 Now it works with Japanese version of OS/2 3352.04 Fixed error when ftruncate used to extend file 3362.05 Fixed crash when got mount parameters without = 337 338 Fixed crash when allocation of anode failed due to full disk 339 340 Fixed some crashes when block io or inode allocation failed 3412.06 Fixed some crash on corrupted disk structures 342 343 Better allocation strategy 344 345 Reschedule points added so that it doesn't lock CPU long time 346 347 It should work in read-only mode on Warp Server 3482.07 More fixes for Warp Server. Now it really works 3492.08 Creating new files is not so slow on large disks 350 351 An attempt to sync deleted file does not generate filesystem error 3522.09 Fixed error on extremely fragmented files 353====== ========================================================================= 354