f24c7c359e
Currently, there are several places in zvol_id where the program logic returns particular errno values, or even particular ioctl return values, as the program exit status, rather than a straightforward system of explicit zero on success and explicit nonzero value(s) on failure. This is problematic for multiple reasons. One particularly interesting problem that can arise, is that if any of these values happens to have all 8 least significant bits unset (i.e., it is a positive or negative multiple of 256), then although the C program sees a nonzero int value (presumed to be a failure exit status), the actual exit status as seen by the system is only the bottom 8 bits of that integer: zero. This can happen in practice, and I have encountered it myself. In a particularly weird situation, the zvol_open code in the zfs kernel module was behaving in such a manner that it caused the open() syscall to fail and for errno to be set to a kernel-private value (ERESTARTSYS, which happens to be defined as 512). It turns out that 512 is evenly divisible by 256; or, in other words, its least significant 8 bits are all-zero. So even though zvol_id believed it was returning a nonzero (failure) exit status of 512, the system modulo'd that value by 256, resulting in the actual exit status visible by other programs being 0! This actually-zero (non-failure) exit status caused problems: udev believed that the program was operating successfully, when in fact it was attempting to indicate failure via a nonzero exit status integer. Combined with another problem, this led to the creation of nonsense symlinks for zvol dev nodes by udev. Let's get rid of all this problematic logic, and simply return EXIT_SUCCESS (0) is everything went fine, and EXIT_FAILURE (1) if anything went wrong. Additionally, let's clarify some of the variable names (error is similar to errno, etc) and clean up the overall program flow a bit. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com> Signed-off-by: Justin Gottula <justin@jgottula.com> Closes #12302 |
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README.md
OpenZFS is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the OpenZFS community. This repository contains the code for running OpenZFS on Linux and FreeBSD.
Official Resources
- Documentation - for using and developing this repo
- ZoL Site - Linux release info & links
- Mailing lists
- OpenZFS site - for conference videos and info on other platforms (illumos, OSX, Windows, etc)
Installation
Full documentation for installing OpenZFS on your favorite operating system can be found at the Getting Started Page.
Contribute & Develop
We have a separate document with contribution guidelines.
We have a Code of Conduct.
Release
OpenZFS is released under a CDDL license.
For more details see the NOTICE, LICENSE and COPYRIGHT files; UCRL-CODE-235197
Supported Kernels
- The
METAfile contains the officially recognized supported Linux kernel versions. - Supported FreeBSD versions are any supported branches and releases starting from 12.2-RELEASE.