068beacf21
folks running filesystems created on check-hash enabled kernels (which I will call "new") on a non-check-hash enabled kernels (which I will call "old). The idea here is to detect when a filesystem is run on an old kernel and flag the filesystem so that when it gets moved back to a new kernel, it will not start getting a slew of check-hash errors. Back when the UFS version 2 filesystem was created, it added a file flag FS_INDEXDIRS that was to be set on any filesystem that kept some sort of on-disk indexing for directories. The idea was precisely to solve the issue we have today. Specifically that a newer kernel that supported indexing would be able to tell that the filesystem had been run on an older non-indexing kernel and that the indexes should not be used until they had been rebuilt. Since we have never implemented on-disk directory indicies, the FS_INDEXDIRS flag is cleared every time any UFS version 2 filesystem ever created is mounted for writing. This commit repurposes the FS_INDEXDIRS flag as the FS_METACKHASH flag. Thus, the FS_METACKHASH is definitively known to have always been cleared. The FS_INDEXDIRS flag has been moved to a new block of flags that will always be cleared starting with this commit (until they get used to implement some future feature which needs to detect that the filesystem was mounted on a kernel that predates the new feature). If a filesystem with check-hashes enabled is mounted on an old kernel the FS_METACKHASH flag is cleared. When that filesystem is mounted on a new kernel it will see that the FS_METACKHASH has been cleared and clears all of the fs_metackhash flags. To get them re-enabled the user must run fsck (in interactive mode without the -y flag) which will ask for each supported check hash whether it should be rebuilt and enabled. When fsck is run in its default preen mode, it will just ignore the check hashes so they will remain disabled. The kernel has always disabled any check hash functions that it does not support, so as more types of check hashes are added, we will get a non-surprising result. Specifically if filesystems get moved to kernels supporting fewer of the check hashes, those that are not supported will be disabled. If the filesystem is moved back to a kernel with more of the check-hashes available and fsck is run interactively to rebuild them, then their checking will resume. Otherwise just the smaller subset will be checked. A side effect of this commit is that filesystems running with cylinder-group check hashes will stop having them checked until fsck is run to re-enable them (since none of them currently have the FS_METACKHASH flag set). So, if you want check hashes enabled on your filesystems after booting a kernel with these changes, you need to run fsck to enable them. Any newly created filesystems will have check hashes enabled. If in doubt as to whether you have check hashes emabled, run dumpfs and look at the list of enabled flags at the end of the superblock details. |
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| bin | ||
| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| stand | ||
| sys | ||
| targets | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| .arcconfig | ||
| .arclint | ||
| .gitattributes | ||
| .gitignore | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.libcompat | ||
| Makefile.sys.inc | ||
| ObsoleteFiles.inc | ||
| README | ||
| README.md | ||
| UPDATING | ||
FreeBSD Source:
This is the top level of the FreeBSD source directory. This file
was last revised on:
FreeBSD
For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information).
The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree. See build(7) and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html for more information, including setting make(1) variables.
The buildkernel and installkernel targets build and install
the kernel and the modules (see below). Please see the top of
the Makefile in this directory for more information on the
standard build targets and compile-time flags.
Building a kernel is a somewhat more involved process. See build(7), config(8), and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information.
Note: If you want to build and install the kernel with the
buildkernel and installkernel targets, you might need to build
world before. More information is available in the handbook.
The kernel configuration files reside in the sys/<arch>/conf
sub-directory. GENERIC is the default configuration used in release builds.
NOTES contains entries and documentation for all possible
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Source Roadmap:
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cddl Various commands and libraries under the Common Development
and Distribution License.
contrib Packages contributed by 3rd parties.
crypto Cryptography stuff (see crypto/README).
etc Template files for /etc.
gnu Various commands and libraries under the GNU Public License.
Please see gnu/COPYING* for more information.
include System include files.
kerberos5 Kerberos5 (Heimdal) package.
lib System libraries.
libexec System daemons.
release Release building Makefile & associated tools.
rescue Build system for statically linked /rescue utilities.
sbin System commands.
secure Cryptographic libraries and commands.
share Shared resources.
stand Boot loader sources.
sys Kernel sources.
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for additional information.
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For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see:
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