Changelog

This is the second beta release of the new Chiron FS 1.1 code base. There is one known bug right now. It is the bug related with massive delete described below. There is a fix for it, but it is still in experimental status. Until now, no one has reported failures related to this bug. If you find any bugs, please report them asap, with as many details as you can: what you were doing, what you have installed in the system, the command line you invoked ChironFS, your current directory, etc.

Bugs fixed since ChironFS 1.1.0:

• ChironFS could not locate the correct place where chirctl was when called using the environment variable $PATH to find it. Now chirctl is called in the same way as ChironFS, leaving this work to $PATH searches.

Changes

Since ChironFS 1.1.0

• ChironFS could not locate the correct place where chirctl was when called using the environment variable $PATH to find it. Now chirctl is called in the same way as ChironFS, leaving this work to $PATH searches.

Since ChironFS 1.0.0

• Added the --ctl (or -c) option which allows to mount a pseudo-filesystem (like /proc) to control the behavior of the Chiron filesystem being mounted. Currently, it's only possible to show the status of the replicas and change their status. Dynamically generated nagios plugin scripts are provided too.
• Updated the howto in the chapter 5, explaining the use of the --ctl option.

Since ChironFS 1.0RC9

• Integrated patch sent by Antti Kantee, porting ChironFS to NetBSD.
• Integrated patch sent by Yen-Ming Lee, porting ChironFS to FreeBSD.
• Changed the debug code on *BSD versions to get the same system information that Linux version gets. It is needed because the next ChironFS release will need that info in order to resynchronize failed replicas.
• The version naming convention: now ChironFS will use a Linux Kernel like versioning scheme. So, the upcoming version 1.1.x will be the development version of the upcoming 1.2.x stable one.

Since ChironFS 1.0RC8

• Fixed bug #8 where an unprivileged user was being able to touch a file which it did not have the rights to write. Thanks to Neal Becker for reporting it.
• Fixed a readlink bug, where the number of bytes of the linked filename was being wrong reported.
• Fixed function access, the access were not being checked against the ruid and rgid of the caller process, but of the mounting user.
• Fixed a memory leak bug.

Since ChironFS 1.0RC7

• Fixed a bug reported by email by Patrick Chevalier, where ChironFS was giving wrong error message when the mount point path did not existed. Thanks to him for the report.
• Fixed bug #7 where ChironFS wasn't being specific in the error message. Thanks to Alexandre Fernandes for reporting it.
• Fixed a bug reported by email by Graham Toal where the hash address of the file descriptor table could be a negative number. The hash table function was changed to the Robert Jenkins' 32 bit integer hash function as found in this Twang's doc just adapted to the C language. The 64 bit mix function was taken from there too. The size of the hash table was changed too it was a waste of memory allocating a table of file-max size because file-max is a system wide parameter and if all the file-system would be ChironFSed and with a minimal of two replicas we would need only 33% of the table space. Since the new hash functions are much better distributed and are good enough until 80% of the space used, then I decided to use a file-max proportional allocation, using the maximum power of 2 less than 50% of file-max. The stats showed a low collision rate for 50% of table usage (about 18% of file-max in my box, which means that, using two replicas, I was using 54% of the system file descriptors). I drew an allocation graphic which can be seen in the howto
• Fixed a bug where a chunk of memory was being freed two times (and crashing ChironFS, but it was going exit anyway) when some replica path didn't existed at mount time.
• Fixed an issue when the ulimit were lower than the projected hash table size, just raising the ulimit value, but it only works if the mounting user is root, otherwise the ulimit must be raised through manual configuration of /etc/security/limits.conf.
• Updated the howto with hash, file descriptor and ulimit considerations.

Since ChironFS 1.0RC6

• Fixed bug #6 where files created by another user than the user that mounted ChironFS were owned by the mounting user and not the creator itself. It was a serious security problem. ChironFS was not tracking the creation of the files and, this way, was not changing the ownership of the created file/directory to the uid and gid of the calling process. Now ChironFS calls fuse_context to get that info from the calling process and changes to it right after the creation. Thanks to Neal Becker who reported the bug.
• Implemented an experimental fix for a bug reported by Oleg Bartunov by e-mail, where ChironFS fails to exclude all files when doing massive delete ("rm -Rf" on directories with thousands of files). It happens when a cycle of opendir/readdir/closedir cannot be done in only one call due to lack of space in the readdir buffer and subsequent calls were lacking of synchronization because the system flushed the deletes and updated the directory list. I started to call seekdir using the offset parameter of the readdir. This parameter were being ignored until now as in the example programs of fuse implementations. Now my tests are succesfull. But, Franco Broi reported at the fuse-devel mailing list that a filesystem he is implementing got the same bug. I told him about my fix and he tested with his filesystem and it did NOT work for him. Miklos Szeredi, the author of fuse proposed another fix and it worked for Franco Broi. But when I implemented it in ChironFS, it made my system crash. Franco Broi told me that his filesystem runs on top of NFS. I did not tested ChironFS over NFS, but my fix worked on top of SSHFS. So, I will keep my fix, but in experimental status. Thanks to Oleg Bartunov for reporting the bug.
• Complete rewrite of the debug function. The old ones were a confusing mess. Now there is only one, accepting variable parameters. Thanks to Graham Toal, author of dupfs, from whose code I learnt the techniques to do it.
• Fixed a bug when ChironFS is called with --log option and the logfile pathname is relative and the file itself doesn't exists. In this case, ChironFS was exiting with the "file not found" error. The problem is that when realpath is called with a non-existant path it returns NULL. So I had to get its basedir, call realpath and only then, re-append the basename to it. Thanks to Graham Toal who reported this bug.
• Implemented a priorization system, modifying the simple round-robin that made the load balance on read operations. Now when we have replicas with a too different response time (tipically a local/LAN replica and a remote WAN replica) the system focus the load balance only in the fast replicas. The slow replicas are accessed in read operations only when the fast ones fails. To enable this, the user MUST tell ChironFS which are the slower replicas by prefixing the pathnames with a colon in the command line, for example: "chironfs /real1=:/real2=/real3=/real4=:/real5 /virtual". In this example, ChironFS will give priority to the /real1, /real3 and /real4 and choosing a replica to read using a round-robin load balance algorithm. ChironFS will read from /real2 and /real5 replicas only if /real1, /real3 and /real4 fail and in this case, will choose between /real2 and /real5 unsing the same round-robin algorithm. Of course most of its usage will be something like "chironfs /real1=:/real2 /virtual", but the example was intended to show more details on how ChironFS will handle these situations. Thanks to Maxime Ritter who gave the idea of configuring the priority in the command line.
• Fixed one more memory leak: I was freeing all paths[i].path allocations, but I forgot to free the paths structure itself.

Since ChironFS 1.0RC5

• Fixed a bug with fsync reported both by Oleg Bartunov by e-mail "(...) postgresql 8.2.4 doesn't works. initdb worked fine, but starting fails (...) PANIC: could not fsync control file: No such file or directory (...)" and by William Maddler "(...) I try to save a file from Vim. (...) 'test' E667: Fsync failed (...) File seems to be saved anyhow. I have no problems using nano or echoing to a file.". It was a wrong return value of the function giving to the application a false negative.

• Fixed bug #5 The man page wasn't being copied to the man directory when installing from the source tarball. I needed to redo all the autoconf/automake/autoheader stuff just to discover that I had to put one line at Makefile.am. Anyway, I needed to change the .spec file and my script to build all the packages too.

Since ChironFS 1.0RC4

• Fixed Bug #3. It was a problem with mknod, which can't be called when using sshfs. Instead we open and close the file. Thanks to Alexandre Fernandes for reporting this bug.

• Fixed Bug #4. There was a mismatch in readdir function when testing if the replica is disabled. I used the wrong index variable. Thanks to Alexandre Fernandes for reporting this bug.

• Added lock control and reopening of the log file, so when you logrotate there will be no need to restart (remount) ChironFS, and, this way, no need to stop all the daemons that uses the ChironFS mounts.

• ChironFS now automatically calls FUSE using the direct_io option so we avoid redundant disk caching

• Fixed wrong error message when a failure occurs calling realpath to canonicalize the replica's paths. I was just reporting low memory and so this message was being displayed when the path was wrong. Now I display the errno message

• Added --version and -V option to command line.

Since ChironFS 1.0RC3

• Bug #2 . Thanks to Marek Kotas for reporting this bug.

Since ChironFS 1.0RC2

• Fixing various memory leaks. Thanks to Patrick Prasse who found these bugs and sent a patch fixing all of them.
• Fixing bug #1 reported at the project issues page. Look at bug #1 to see the details. Thanks to Marcelo Squeff who found this bug.

Since ChironFS 1.0RC1

• Correcting file permissions at the creation of the log file. It was world writable. Thanks to Jason Haar who found this bug.

Since ChironFS 0.5

• Luis Otavio de Colla Furquim
  • Adoption of a struct to handle all the data about the replicas. Version 0.5 just used strings to store the pathname to them. Now the system have a status field indicating if it is enabled or disabled and the time when it was disabled. The fields with usage statistics were been defined but they are not used yet.
  • Some write functions were behaving as read functions: they were not writing to all replicas, but to the first available one.
  • Implemented a simple round robin algorithm to load balance the read operations. Version 0.5 was reading everything from the first replica available.
  • Implemented a logging system. This system does not logs all the activity. It logs just when some operation fails but some are succesfull. In this case if the operation is a reading operation Chiron FS logs but does not disable the replica because the replicas are still consistent. But if the operation is for write, then Chiron FS logs the failure AND disable the inconsistent replica.