1Read/Write HPFS 2.09 21998-2004, Mikulas Patocka 3 4email: mikulas@artax.karlin.mff.cuni.cz 5homepage: http://artax.karlin.mff.cuni.cz/~mikulas/vyplody/hpfs/index-e.cgi 6 7CREDITS: 8Chris Smith, 1993, original read-only HPFS, some code and hpfs structures file 9 is taken from it 10Jacques Gelinas, MSDos mmap, Inspired by fs/nfs/mmap.c (Jon Tombs 15 Aug 1993) 11Werner Almesberger, 1992, 1993, MSDos option parser & CR/LF conversion 12 13Mount options 14 15uid=xxx,gid=xxx,umask=xxx (default uid=gid=0 umask=default_system_umask) 16 Set owner/group/mode for files that do not have it specified in extended 17 attributes. Mode is inverted umask - for example umask 027 gives owner 18 all permission, group read permission and anybody else no access. Note 19 that for files mode is anded with 0666. If you want files to have 'x' 20 rights, you must use extended attributes. 21case=lower,asis (default asis) 22 File name lowercasing in readdir. 23conv=binary,text,auto (default binary) 24 CR/LF -> LF conversion, if auto, decision is made according to extension 25 - there is a list of text extensions (I thing it's better to not convert 26 text file than to damage binary file). If you want to change that list, 27 change it in the source. Original readonly HPFS contained some strange 28 heuristic algorithm that I removed. I thing it's danger to let the 29 computer decide whether file is text or binary. For example, DJGPP 30 binaries contain small text message at the beginning and they could be 31 misidentified and damaged under some circumstances. 32check=none,normal,strict (default normal) 33 Check level. Selecting none will cause only little speedup and big 34 danger. I tried to write it so that it won't crash if check=normal on 35 corrupted filesystems. check=strict means many superfluous checks - 36 used for debugging (for example it checks if file is allocated in 37 bitmaps when accessing it). 38errors=continue,remount-ro,panic (default remount-ro) 39 Behaviour when filesystem errors found. 40chkdsk=no,errors,always (default errors) 41 When to mark filesystem dirty so that OS/2 checks it. 42eas=no,ro,rw (default rw) 43 What to do with extended attributes. 'no' - ignore them and use always 44 values specified in uid/gid/mode options. 'ro' - read extended 45 attributes but do not create them. 'rw' - create extended attributes 46 when you use chmod/chown/chgrp/mknod/ln -s on the filesystem. 47timeshift=(-)nnn (default 0) 48 Shifts the time by nnn seconds. For example, if you see under linux 49 one hour more, than under os/2, use timeshift=-3600. 50 51 52File names 53 54As in OS/2, filenames are case insensitive. However, shell thinks that names 55are case sensitive, so for example when you create a file FOO, you can use 56'cat FOO', 'cat Foo', 'cat foo' or 'cat F*' but not 'cat f*'. Note, that you 57also won't be able to compile linux kernel (and maybe other things) on HPFS 58because kernel creates different files with names like bootsect.S and 59bootsect.s. When searching for file thats name has characters >= 128, codepages 60are used - see below. 61OS/2 ignores dots and spaces at the end of file name, so this driver does as 62well. If you create 'a. ...', the file 'a' will be created, but you can still 63access it under names 'a.', 'a..', 'a . . . ' etc. 64 65 66Extended attributes 67 68On HPFS partitions, OS/2 can associate to each file a special information called 69extended attributes. Extended attributes are pairs of (key,value) where key is 70an ascii string identifying that attribute and value is any string of bytes of 71variable length. OS/2 stores window and icon positions and file types there. So 72why not use it for unix-specific info like file owner or access rights? This 73driver can do it. If you chown/chgrp/chmod on a hpfs partition, extended 74attributes with keys "UID", "GID" or "MODE" and 2-byte values are created. Only 75that extended attributes those value differs from defaults specified in mount 76options are created. Once created, the extended attributes are never deleted, 77they're just changed. It means that when your default uid=0 and you type 78something like 'chown luser file; chown root file' the file will contain 79extended attribute UID=0. And when you umount the fs and mount it again with 80uid=luser_uid, the file will be still owned by root! If you chmod file to 444, 81extended attribute "MODE" will not be set, this special case is done by setting 82read-only flag. When you mknod a block or char device, besides "MODE", the 83special 4-byte extended attribute "DEV" will be created containing the device 84number. Currently this driver cannot resize extended attributes - it means 85that if somebody (I don't know who?) has set "UID", "GID", "MODE" or "DEV" 86attributes with different sizes, they won't be rewritten and changing these 87values doesn't work. 88 89 90Symlinks 91 92You can do symlinks on HPFS partition, symlinks are achieved by setting extended 93attribute named "SYMLINK" with symlink value. Like on ext2, you can chown and 94chgrp symlinks but I don't know what is it good for. chmoding symlink results 95in chmoding file where symlink points. These symlinks are just for Linux use and 96incompatible with OS/2. OS/2 PmShell symlinks are not supported because they are 97stored in very crazy way. They tried to do it so that link changes when file is 98moved ... sometimes it works. But the link is partly stored in directory 99extended attributes and partly in OS2SYS.INI. I don't want (and don't know how) 100to analyze or change OS2SYS.INI. 101 102 103Codepages 104 105HPFS can contain several uppercasing tables for several codepages and each 106file has a pointer to codepage its name is in. However OS/2 was created in 107America where people don't care much about codepages and so multiple codepages 108support is quite buggy. I have Czech OS/2 working in codepage 852 on my disk. 109Once I booted English OS/2 working in cp 850 and I created a file on my 852 110partition. It marked file name codepage as 850 - good. But when I again booted 111Czech OS/2, the file was completely inaccessible under any name. It seems that 112OS/2 uppercases the search pattern with its system code page (852) and file 113name it's comparing to with its code page (850). These could never match. Is it 114really what IBM developers wanted? But problems continued. When I created in 115Czech OS/2 another file in that directory, that file was inaccessible too. OS/2 116probably uses different uppercasing method when searching where to place a file 117(note, that files in HPFS directory must be sorted) and when searching for 118a file. Finally when I opened this directory in PmShell, PmShell crashed (the 119funny thing was that, when rebooted, PmShell tried to reopen this directory 120again :-). chkdsk happily ignores these errors and only low-level disk 121modification saved me. Never mix different language versions of OS/2 on one 122system although HPFS was designed to allow that. 123OK, I could implement complex codepage support to this driver but I think it 124would cause more problems than benefit with such buggy implementation in OS/2. 125So this driver simply uses first codepage it finds for uppercasing and 126lowercasing no matter what's file codepage index. Usually all file names are in 127this codepage - if you don't try to do what I described above :-) 128 129 130Known bugs 131 132HPFS386 on OS/2 server is not supported. HPFS386 installed on normal OS/2 client 133should work. If you have OS/2 server, use only read-only mode. I don't know how 134to handle some HPFS386 structures like access control list or extended perm 135list, I don't know how to delete them when file is deleted and how to not 136overwrite them with extended attributes. Send me some info on these structures 137and I'll make it. However, this driver should detect presence of HPFS386 138structures, remount read-only and not destroy them (I hope). 139 140When there's not enough space for extended attributes, they will be truncated 141and no error is returned. 142 143OS/2 can't access files if the path is longer than about 256 chars but this 144driver allows you to do it. chkdsk ignores such errors. 145 146Sometimes you won't be able to delete some files on a very full filesystem 147(returning error ENOSPC). That's because file in non-leaf node in directory tree 148(one directory, if it's large, has dirents in tree on HPFS) must be replaced 149with another node when deleted. And that new file might have larger name than 150the old one so the new name doesn't fit in directory node (dnode). And that 151would result in directory tree splitting, that takes disk space. Workaround is 152to delete other files that are leaf (probability that the file is non-leaf is 153about 1/50) or to truncate file first to make some space. 154You encounter this problem only if you have many directories so that 155preallocated directory band is full i.e. 156 number_of_directories / size_of_filesystem_in_mb > 4. 157 158You can't delete open directories. 159 160You can't rename over directories (what is it good for?). 161 162Renaming files so that only case changes doesn't work. This driver supports it 163but vfs doesn't. Something like 'mv file FILE' won't work. 164 165All atimes and directory mtimes are not updated. That's because of performance 166reasons. If you extremely wish to update them, let me know, I'll write it (but 167it will be slow). 168 169When the system is out of memory and swap, it may slightly corrupt filesystem 170(lost files, unbalanced directories). (I guess all filesystem may do it). 171 172When compiled, you get warning: function declaration isn't a prototype. Does 173anybody know what does it mean? 174 175 176What does "unbalanced tree" message mean? 177 178Old versions of this driver created sometimes unbalanced dnode trees. OS/2 179chkdsk doesn't scream if the tree is unbalanced (and sometimes creates 180unbalanced trees too :-) but both HPFS and HPFS386 contain bug that it rarely 181crashes when the tree is not balanced. This driver handles unbalanced trees 182correctly and writes warning if it finds them. If you see this message, this is 183probably because of directories created with old version of this driver. 184Workaround is to move all files from that directory to another and then back 185again. Do it in Linux, not OS/2! If you see this message in directory that is 186whole created by this driver, it is BUG - let me know about it. 187 188 189Bugs in OS/2 190 191When you have two (or more) lost directories pointing each to other, chkdsk 192locks up when repairing filesystem. 193 194Sometimes (I think it's random) when you create a file with one-char name under 195OS/2, OS/2 marks it as 'long'. chkdsk then removes this flag saying "Minor fs 196error corrected". 197 198File names like "a .b" are marked as 'long' by OS/2 but chkdsk "corrects" it and 199marks them as short (and writes "minor fs error corrected"). This bug is not in 200HPFS386. 201 202Codepage bugs described above. 203 204If you don't install fixpacks, there are many, many more... 205 206 207History 208 2090.90 First public release 2100.91 Fixed bug that caused shooting to memory when write_inode was called on 211 open inode (rarely happened) 2120.92 Fixed a little memory leak in freeing directory inodes 2130.93 Fixed bug that locked up the machine when there were too many filenames 214 with first 15 characters same 215 Fixed write_file to zero file when writing behind file end 2160.94 Fixed a little memory leak when trying to delete busy file or directory 2170.95 Fixed a bug that i_hpfs_parent_dir was not updated when moving files 2181.90 First version for 2.1.1xx kernels 2191.91 Fixed a bug that chk_sectors failed when sectors were at the end of disk 220 Fixed a race-condition when write_inode is called while deleting file 221 Fixed a bug that could possibly happen (with very low probability) when 222 using 0xff in filenames 223 Rewritten locking to avoid race-conditions 224 Mount option 'eas' now works 225 Fsync no longer returns error 226 Files beginning with '.' are marked hidden 227 Remount support added 228 Alloc is not so slow when filesystem becomes full 229 Atimes are no more updated because it slows down operation 230 Code cleanup (removed all commented debug prints) 2311.92 Corrected a bug when sync was called just before closing file 2321.93 Modified, so that it works with kernels >= 2.1.131, I don't know if it 233 works with previous versions 234 Fixed a possible problem with disks > 64G (but I don't have one, so I can't 235 test it) 236 Fixed a file overflow at 2G 237 Added new option 'timeshift' 238 Changed behaviour on HPFS386: It is now possible to operate on HPFS386 in 239 read-only mode 240 Fixed a bug that slowed down alloc and prevented allocating 100% space 241 (this bug was not destructive) 2421.94 Added workaround for one bug in Linux 243 Fixed one buffer leak 244 Fixed some incompatibilities with large extended attributes (but it's still 245 not 100% ok, I have no info on it and OS/2 doesn't want to create them) 246 Rewritten allocation 247 Fixed a bug with i_blocks (du sometimes didn't display correct values) 248 Directories have no longer archive attribute set (some programs don't like 249 it) 250 Fixed a bug that it set badly one flag in large anode tree (it was not 251 destructive) 2521.95 Fixed one buffer leak, that could happen on corrupted filesystem 253 Fixed one bug in allocation in 1.94 2541.96 Added workaround for one bug in OS/2 (HPFS locked up, HPFS386 reported 255 error sometimes when opening directories in PMSHELL) 256 Fixed a possible bitmap race 257 Fixed possible problem on large disks 258 You can now delete open files 259 Fixed a nondestructive race in rename 2601.97 Support for HPFS v3 (on large partitions) 261 Fixed a bug that it didn't allow creation of files > 128M (it should be 2G) 2621.97.1 Changed names of global symbols 263 Fixed a bug when chmoding or chowning root directory 2641.98 Fixed a deadlock when using old_readdir 265 Better directory handling; workaround for "unbalanced tree" bug in OS/2 2661.99 Corrected a possible problem when there's not enough space while deleting 267 file 268 Now it tries to truncate the file if there's not enough space when deleting 269 Removed a lot of redundant code 2702.00 Fixed a bug in rename (it was there since 1.96) 271 Better anti-fragmentation strategy 2722.01 Fixed problem with directory listing over NFS 273 Directory lseek now checks for proper parameters 274 Fixed race-condition in buffer code - it is in all filesystems in Linux; 275 when reading device (cat /dev/hda) while creating files on it, files 276 could be damaged 2772.02 Workaround for bug in breada in Linux. breada could cause accesses beyond 278 end of partition 2792.03 Char, block devices and pipes are correctly created 280 Fixed non-crashing race in unlink (Alexander Viro) 281 Now it works with Japanese version of OS/2 2822.04 Fixed error when ftruncate used to extend file 2832.05 Fixed crash when got mount parameters without = 284 Fixed crash when allocation of anode failed due to full disk 285 Fixed some crashes when block io or inode allocation failed 2862.06 Fixed some crash on corrupted disk structures 287 Better allocation strategy 288 Reschedule points added so that it doesn't lock CPU long time 289 It should work in read-only mode on Warp Server 2902.07 More fixes for Warp Server. Now it really works 2912.08 Creating new files is not so slow on large disks 292 An attempt to sync deleted file does not generate filesystem error 2932.09 Fixed error on extremely fragmented files 294 295 296 vim: set textwidth=80: 297