This patch fixes typos in various Documentation txts. The patch addresses some +words starting with the letters 'U-Z'. Looks like I made it through the alphabet...just in time to start over again +too! Maybe I can fit more profound fixes into the next round...? Time will +tell. :) Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com> Acked-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Adrian Bunk <bunk@stusta.de>
296 lines
15 KiB
Text
296 lines
15 KiB
Text
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 it's 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 extremly fragmented files
|
|
|
|
|
|
vim: set textwidth=80:
|