|  | Read/Write HPFS 2.09 | 
|  | 1998-2004, Mikulas Patocka | 
|  |  | 
|  | email: mikulas@artax.karlin.mff.cuni.cz | 
|  | homepage: http://artax.karlin.mff.cuni.cz/~mikulas/vyplody/hpfs/index-e.cgi | 
|  |  | 
|  | CREDITS: | 
|  | Chris Smith, 1993, original read-only HPFS, some code and hpfs structures file | 
|  | is taken from it | 
|  | Jacques Gelinas, MSDos mmap, Inspired by fs/nfs/mmap.c (Jon Tombs 15 Aug 1993) | 
|  | Werner Almesberger, 1992, 1993, MSDos option parser & CR/LF conversion | 
|  |  | 
|  | Mount options | 
|  |  | 
|  | uid=xxx,gid=xxx,umask=xxx (default uid=gid=0 umask=default_system_umask) | 
|  | Set owner/group/mode for files that do not have it specified in extended | 
|  | attributes. Mode is inverted umask - for example umask 027 gives owner | 
|  | all permission, group read permission and anybody else no access. Note | 
|  | that for files mode is anded with 0666. If you want files to have 'x' | 
|  | rights, you must use extended attributes. | 
|  | case=lower,asis (default asis) | 
|  | File name lowercasing in readdir. | 
|  | conv=binary,text,auto (default binary) | 
|  | CR/LF -> LF conversion, if auto, decision is made according to extension | 
|  | - there is a list of text extensions (I thing it's better to not convert | 
|  | text file than to damage binary file). If you want to change that list, | 
|  | change it in the source. Original readonly HPFS contained some strange | 
|  | heuristic algorithm that I removed. I thing it's danger to let the | 
|  | computer decide whether file is text or binary. For example, DJGPP | 
|  | binaries contain small text message at the beginning and they could be | 
|  | misidentified and damaged under some circumstances. | 
|  | check=none,normal,strict (default normal) | 
|  | Check level. Selecting none will cause only little speedup and big | 
|  | danger. I tried to write it so that it won't crash if check=normal on | 
|  | corrupted filesystems. check=strict means many superfluous checks - | 
|  | used for debugging (for example it checks if file is allocated in | 
|  | bitmaps when accessing it). | 
|  | errors=continue,remount-ro,panic (default remount-ro) | 
|  | Behaviour when filesystem errors found. | 
|  | chkdsk=no,errors,always (default errors) | 
|  | When to mark filesystem dirty so that OS/2 checks it. | 
|  | eas=no,ro,rw (default rw) | 
|  | What to do with extended attributes. 'no' - ignore them and use always | 
|  | values specified in uid/gid/mode options. 'ro' - read extended | 
|  | attributes but do not create them. 'rw' - create extended attributes | 
|  | when you use chmod/chown/chgrp/mknod/ln -s on the filesystem. | 
|  | timeshift=(-)nnn (default 0) | 
|  | Shifts the time by nnn seconds. For example, if you see under linux | 
|  | one hour more, than under os/2, use timeshift=-3600. | 
|  |  | 
|  |  | 
|  | File names | 
|  |  | 
|  | As in OS/2, filenames are case insensitive. However, shell thinks that names | 
|  | are case sensitive, so for example when you create a file FOO, you can use | 
|  | 'cat FOO', 'cat Foo', 'cat foo' or 'cat F*' but not 'cat f*'. Note, that you | 
|  | also won't be able to compile linux kernel (and maybe other things) on HPFS | 
|  | because kernel creates different files with names like bootsect.S and | 
|  | bootsect.s. When searching for file thats name has characters >= 128, codepages | 
|  | are used - see below. | 
|  | OS/2 ignores dots and spaces at the end of file name, so this driver does as | 
|  | well. If you create 'a. ...', the file 'a' will be created, but you can still | 
|  | access it under names 'a.', 'a..', 'a .  . . ' etc. | 
|  |  | 
|  |  | 
|  | Extended attributes | 
|  |  | 
|  | On HPFS partitions, OS/2 can associate to each file a special information called | 
|  | extended attributes. Extended attributes are pairs of (key,value) where key is | 
|  | an ascii string identifying that attribute and value is any string of bytes of | 
|  | variable length. OS/2 stores window and icon positions and file types there. So | 
|  | why not use it for unix-specific info like file owner or access rights? This | 
|  | driver can do it. If you chown/chgrp/chmod on a hpfs partition, extended | 
|  | attributes with keys "UID", "GID" or "MODE" and 2-byte values are created. Only | 
|  | that extended attributes those value differs from defaults specified in mount | 
|  | options are created. Once created, the extended attributes are never deleted, | 
|  | they're just changed. It means that when your default uid=0 and you type | 
|  | something like 'chown luser file; chown root file' the file will contain | 
|  | extended attribute UID=0. And when you umount the fs and mount it again with | 
|  | uid=luser_uid, the file will be still owned by root! If you chmod file to 444, | 
|  | extended attribute "MODE" will not be set, this special case is done by setting | 
|  | read-only flag. When you mknod a block or char device, besides "MODE", the | 
|  | special 4-byte extended attribute "DEV" will be created containing the device | 
|  | number. Currently this driver cannot resize extended attributes - it means | 
|  | that if somebody (I don't know who?) has set "UID", "GID", "MODE" or "DEV" | 
|  | attributes with different sizes, they won't be rewritten and changing these | 
|  | values doesn't work. | 
|  |  | 
|  |  | 
|  | Symlinks | 
|  |  | 
|  | You can do symlinks on HPFS partition, symlinks are achieved by setting extended | 
|  | attribute named "SYMLINK" with symlink value. Like on ext2, you can chown and | 
|  | chgrp symlinks but I don't know what is it good for. chmoding symlink results | 
|  | in chmoding file where symlink points. These symlinks are just for Linux use and | 
|  | incompatible with OS/2. OS/2 PmShell symlinks are not supported because they are | 
|  | stored in very crazy way. They tried to do it so that link changes when file is | 
|  | moved ... sometimes it works. But the link is partly stored in directory | 
|  | extended attributes and partly in OS2SYS.INI. I don't want (and don't know how) | 
|  | to analyze or change OS2SYS.INI. | 
|  |  | 
|  |  | 
|  | Codepages | 
|  |  | 
|  | HPFS can contain several uppercasing tables for several codepages and each | 
|  | file has a pointer to codepage its name is in. However OS/2 was created in | 
|  | America where people don't care much about codepages and so multiple codepages | 
|  | support is quite buggy. I have Czech OS/2 working in codepage 852 on my disk. | 
|  | Once I booted English OS/2 working in cp 850 and I created a file on my 852 | 
|  | partition. It marked file name codepage as 850 - good. But when I again booted | 
|  | Czech OS/2, the file was completely inaccessible under any name. It seems that | 
|  | OS/2 uppercases the search pattern with its system code page (852) and file | 
|  | name it's comparing to with its code page (850). These could never match. Is it | 
|  | really what IBM developers wanted? But problems continued. When I created in | 
|  | Czech OS/2 another file in that directory, that file was inaccessible too. OS/2 | 
|  | probably uses different uppercasing method when searching where to place a file | 
|  | (note, that files in HPFS directory must be sorted) and when searching for | 
|  | a file. Finally when I opened this directory in PmShell, PmShell crashed (the | 
|  | funny thing was that, when rebooted, PmShell tried to reopen this directory | 
|  | again :-). chkdsk happily ignores these errors and only low-level disk | 
|  | modification saved me.  Never mix different language versions of OS/2 on one | 
|  | system although HPFS was designed to allow that. | 
|  | OK, I could implement complex codepage support to this driver but I think it | 
|  | would cause more problems than benefit with such buggy implementation in OS/2. | 
|  | So this driver simply uses first codepage it finds for uppercasing and | 
|  | lowercasing no matter what's file codepage index. Usually all file names are in | 
|  | this codepage - if you don't try to do what I described above :-) | 
|  |  | 
|  |  | 
|  | Known bugs | 
|  |  | 
|  | HPFS386 on OS/2 server is not supported. HPFS386 installed on normal OS/2 client | 
|  | should work. If you have OS/2 server, use only read-only mode. I don't know how | 
|  | to handle some HPFS386 structures like access control list or extended perm | 
|  | list, I don't know how to delete them when file is deleted and how to not | 
|  | overwrite them with extended attributes. Send me some info on these structures | 
|  | and I'll make it. However, this driver should detect presence of HPFS386 | 
|  | structures, remount read-only and not destroy them (I hope). | 
|  |  | 
|  | When there's not enough space for extended attributes, they will be truncated | 
|  | and no error is returned. | 
|  |  | 
|  | OS/2 can't access files if the path is longer than about 256 chars but this | 
|  | driver allows you to do it. chkdsk ignores such errors. | 
|  |  | 
|  | Sometimes you won't be able to delete some files on a very full filesystem | 
|  | (returning error ENOSPC). That's because file in non-leaf node in directory tree | 
|  | (one directory, if it's large, has dirents in tree on HPFS) must be replaced | 
|  | with another node when deleted. And that new file might have larger name than | 
|  | the old one so the new name doesn't fit in directory node (dnode). And that | 
|  | would result in directory tree splitting, that takes disk space. Workaround is | 
|  | to delete other files that are leaf (probability that the file is non-leaf is | 
|  | about 1/50) or to truncate file first to make some space. | 
|  | You encounter this problem only if you have many directories so that | 
|  | preallocated directory band is full i.e. | 
|  | number_of_directories / size_of_filesystem_in_mb > 4. | 
|  |  | 
|  | You can't delete open directories. | 
|  |  | 
|  | You can't rename over directories (what is it good for?). | 
|  |  | 
|  | Renaming files so that only case changes doesn't work. This driver supports it | 
|  | but vfs doesn't. Something like 'mv file FILE' won't work. | 
|  |  | 
|  | All atimes and directory mtimes are not updated. That's because of performance | 
|  | reasons. If you extremely wish to update them, let me know, I'll write it (but | 
|  | it will be slow). | 
|  |  | 
|  | When the system is out of memory and swap, it may slightly corrupt filesystem | 
|  | (lost files, unbalanced directories). (I guess all filesystem may do it). | 
|  |  | 
|  | When compiled, you get warning: function declaration isn't a prototype. Does | 
|  | anybody know what does it mean? | 
|  |  | 
|  |  | 
|  | What does "unbalanced tree" message mean? | 
|  |  | 
|  | Old versions of this driver created sometimes unbalanced dnode trees. OS/2 | 
|  | chkdsk doesn't scream if the tree is unbalanced (and sometimes creates | 
|  | unbalanced trees too :-) but both HPFS and HPFS386 contain bug that it rarely | 
|  | crashes when the tree is not balanced. This driver handles unbalanced trees | 
|  | correctly and writes warning if it finds them. If you see this message, this is | 
|  | probably because of directories created with old version of this driver. | 
|  | Workaround is to move all files from that directory to another and then back | 
|  | again. Do it in Linux, not OS/2! If you see this message in directory that is | 
|  | whole created by this driver, it is BUG - let me know about it. | 
|  |  | 
|  |  | 
|  | Bugs in OS/2 | 
|  |  | 
|  | When you have two (or more) lost directories pointing each to other, chkdsk | 
|  | locks up when repairing filesystem. | 
|  |  | 
|  | Sometimes (I think it's random) when you create a file with one-char name under | 
|  | OS/2, OS/2 marks it as 'long'. chkdsk then removes this flag saying "Minor fs | 
|  | error corrected". | 
|  |  | 
|  | File names like "a .b" are marked as 'long' by OS/2 but chkdsk "corrects" it and | 
|  | marks them as short (and writes "minor fs error corrected"). This bug is not in | 
|  | HPFS386. | 
|  |  | 
|  | Codepage bugs described above. | 
|  |  | 
|  | If you don't install fixpacks, there are many, many more... | 
|  |  | 
|  |  | 
|  | History | 
|  |  | 
|  | 0.90 First public release | 
|  | 0.91 Fixed bug that caused shooting to memory when write_inode was called on | 
|  | open inode (rarely happened) | 
|  | 0.92 Fixed a little memory leak in freeing directory inodes | 
|  | 0.93 Fixed bug that locked up the machine when there were too many filenames | 
|  | with first 15 characters same | 
|  | Fixed write_file to zero file when writing behind file end | 
|  | 0.94 Fixed a little memory leak when trying to delete busy file or directory | 
|  | 0.95 Fixed a bug that i_hpfs_parent_dir was not updated when moving files | 
|  | 1.90 First version for 2.1.1xx kernels | 
|  | 1.91 Fixed a bug that chk_sectors failed when sectors were at the end of disk | 
|  | Fixed a race-condition when write_inode is called while deleting file | 
|  | Fixed a bug that could possibly happen (with very low probability) when | 
|  | using 0xff in filenames | 
|  | Rewritten locking to avoid race-conditions | 
|  | Mount option 'eas' now works | 
|  | Fsync no longer returns error | 
|  | Files beginning with '.' are marked hidden | 
|  | Remount support added | 
|  | Alloc is not so slow when filesystem becomes full | 
|  | Atimes are no more updated because it slows down operation | 
|  | Code cleanup (removed all commented debug prints) | 
|  | 1.92 Corrected a bug when sync was called just before closing file | 
|  | 1.93 Modified, so that it works with kernels >= 2.1.131, I don't know if it | 
|  | works with previous versions | 
|  | Fixed a possible problem with disks > 64G (but I don't have one, so I can't | 
|  | test it) | 
|  | Fixed a file overflow at 2G | 
|  | Added new option 'timeshift' | 
|  | Changed behaviour on HPFS386: It is now possible to operate on HPFS386 in | 
|  | read-only mode | 
|  | Fixed a bug that slowed down alloc and prevented allocating 100% space | 
|  | (this bug was not destructive) | 
|  | 1.94 Added workaround for one bug in Linux | 
|  | Fixed one buffer leak | 
|  | Fixed some incompatibilities with large extended attributes (but it's still | 
|  | not 100% ok, I have no info on it and OS/2 doesn't want to create them) | 
|  | Rewritten allocation | 
|  | Fixed a bug with i_blocks (du sometimes didn't display correct values) | 
|  | Directories have no longer archive attribute set (some programs don't like | 
|  | it) | 
|  | Fixed a bug that it set badly one flag in large anode tree (it was not | 
|  | destructive) | 
|  | 1.95 Fixed one buffer leak, that could happen on corrupted filesystem | 
|  | Fixed one bug in allocation in 1.94 | 
|  | 1.96 Added workaround for one bug in OS/2 (HPFS locked up, HPFS386 reported | 
|  | error sometimes when opening directories in PMSHELL) | 
|  | Fixed a possible bitmap race | 
|  | Fixed possible problem on large disks | 
|  | You can now delete open files | 
|  | Fixed a nondestructive race in rename | 
|  | 1.97 Support for HPFS v3 (on large partitions) | 
|  | Fixed a bug that it didn't allow creation of files > 128M (it should be 2G) | 
|  | 1.97.1 Changed names of global symbols | 
|  | Fixed a bug when chmoding or chowning root directory | 
|  | 1.98 Fixed a deadlock when using old_readdir | 
|  | Better directory handling; workaround for "unbalanced tree" bug in OS/2 | 
|  | 1.99 Corrected a possible problem when there's not enough space while deleting | 
|  | file | 
|  | Now it tries to truncate the file if there's not enough space when deleting | 
|  | Removed a lot of redundant code | 
|  | 2.00 Fixed a bug in rename (it was there since 1.96) | 
|  | Better anti-fragmentation strategy | 
|  | 2.01 Fixed problem with directory listing over NFS | 
|  | Directory lseek now checks for proper parameters | 
|  | Fixed race-condition in buffer code - it is in all filesystems in Linux; | 
|  | when reading device (cat /dev/hda) while creating files on it, files | 
|  | could be damaged | 
|  | 2.02 Workaround for bug in breada in Linux. breada could cause accesses beyond | 
|  | end of partition | 
|  | 2.03 Char, block devices and pipes are correctly created | 
|  | Fixed non-crashing race in unlink (Alexander Viro) | 
|  | Now it works with Japanese version of OS/2 | 
|  | 2.04 Fixed error when ftruncate used to extend file | 
|  | 2.05 Fixed crash when got mount parameters without = | 
|  | Fixed crash when allocation of anode failed due to full disk | 
|  | Fixed some crashes when block io or inode allocation failed | 
|  | 2.06 Fixed some crash on corrupted disk structures | 
|  | Better allocation strategy | 
|  | Reschedule points added so that it doesn't lock CPU long time | 
|  | It should work in read-only mode on Warp Server | 
|  | 2.07 More fixes for Warp Server. Now it really works | 
|  | 2.08 Creating new files is not so slow on large disks | 
|  | An attempt to sync deleted file does not generate filesystem error | 
|  | 2.09 Fixed error on extremely fragmented files | 
|  |  | 
|  |  | 
|  | vim: set textwidth=80: |