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diff --git a/Documentation/filesystems/hpfs.txt b/Documentation/filesystems/hpfs.txt deleted file mode 100644 index 74630bd504fb..000000000000 --- a/Documentation/filesystems/hpfs.txt +++ /dev/null @@ -1,296 +0,0 @@ -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: |