mirror of
https://git.proxmox.com/git/mirror_zfs.git
synced 2025-01-25 01:16:34 +03:00
cecb7487fc
Userland tools such as blkid, grub2-probe and zdb will go through the buffer cache. However, ZFS uses on submit_bio() to bypass the buffer cache when performing IO operations on vdevs for efficiency purposes. This permits the on-disk state and buffer cache to fall out of synchronization. That causes seemingly random failures when tools reading stale metadata from the buffer cache try to access references to data that is no longer there. A particularly bad failure this causes involves grub2-probe, which is used by grub2-mkconfig. Ordinarily, a rootfs might be called rpool/ROOT/gentoo. However, when a failure occurs in grub2-probe, grub2-mkconfig will generate a configuration file containing /ROOT/gentoo, which omits the pool name and causes a boot failure. This is avoidable by calling invalidate_bdev() on each flush, which is a simple way to ensure that all non-dirty pages are wiped. Since userland tools rarely access vdevs directly, this should be a fancy noop >99.999% of the time and have little impact on IO. We could have tried a finer grained approach for the rare instances in which the vdevs are accessed frequently by userland. However, that would require consideration of corner cases and it is not worth the effort. Memory-wise, it would have been better to use a Linux kernel API hook to disable the buffer cache on such devices, but it provides us no way of doing that, so we opt for this approach instead. We should revisit that idea in the future when higher priority issues have been tackled. Signed-off-by: Richard Yao <ryao@gentoo.org> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #2150 |
||
|---|---|---|
| cmd | ||
| config | ||
| dracut | ||
| etc | ||
| include | ||
| lib | ||
| man | ||
| module | ||
| patches | ||
| rpm | ||
| scripts | ||
| udev | ||
| .gitignore | ||
| .gitmodules | ||
| AUTHORS | ||
| autogen.sh | ||
| configure.ac | ||
| copy-builtin | ||
| COPYRIGHT | ||
| DISCLAIMER | ||
| Makefile.am | ||
| META | ||
| OPENSOLARIS.LICENSE | ||
| README.markdown | ||
| zfs-script-config.sh.in | ||
| zfs.release.in | ||
Native ZFS for Linux!
ZFS is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the Illumos community.
ZFS on Linux, which is also known as ZoL, is currently feature complete. It includes fully functional and stable SPA, DMU, ZVOL, and ZPL layers.
Full documentation for installing ZoL on your favorite Linux distribution can be found at: http://zfsonlinux.org