|Read/Write HPFS 2.09
|1998-2004, Mikulas Patocka
|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
|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.
|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.
|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.
|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.
|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 :-)
|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
|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
|Codepage bugs described above.
|If you don't install fixpacks, there are many, many more...
|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
| Fixed a bug that it set badly one flag in large anode tree (it was not
|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
| 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: