9c8fabffa2
The Linux 5.16.14 kernel's coccicheck caught this. The semantic patch that caught it was: ./scripts/coccinelle/misc/flexible_array.cocci However, unlike the cases where the GNU zero length array extension had been used, coccicheck would not suggest patches for the older style single member arrays. That was good because blindly changing them would break size calculations in most cases. Therefore, this required care to make sure that we did not break size calculations. In the case of `indirect_split_t`, we use `offsetof(indirect_split_t, is_child[is->is_children])` to calculate size. This might be subtly wrong according to an old mailing list thread: https://inbox.sourceware.org/gcc-prs/20021226123454.27019.qmail@sources.redhat.com/T/ That is because the C99 specification should consider the flexible array members to start at the end of a structure, but compilers prefer to put padding at the end. A suggestion was made to allow compilers to allocate padding after the VLA like compilers already did: http://std.dkuug.dk/JTC1/SC22/WG14/www/docs/n983.htm However, upon thinking about it, whether or not we allocate end of structure padding does not matter, so using offsetof() to calculate the size of the structure is fine, so long as we do not mix it with sizeof() on structures with no array members. In the case that we mix them and padding causes offsetof(struct_t, vla_member[0]) to differ from sizeof(struct_t), we would be doing unsafe operations if we underallocate via `offsetof()` and then overcopy via sizeof(). Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu> Closes #14372 |
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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.