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POSIX_FADV_DONTNEED). The most broken case was for applications that advise for the whole file and then do block-aligned i/o's 1 block at a time. Then advice is sent to VOP_ADVISE() 1 block at a time, but in vop_stdadvise() the 1-block advice was turned into 0-block advice for the buffer cache part. The bugs were caused partly by callers representing the region as (a_start, a_end), where a_end is actually the maximum, and everything else representing the region as (start, end) where 'end' is actually the end (1 after the maximum). The maximum a_end must be rounded up, but was rounded down. Also, rounding to page boundaries was inconsistent. The bugs and fixes have no effect for zfs and other file systems that don't use the buffer cache or the page cache. Most or all file systems currently use the default VOP_FADVISE(), but it finds a null buffer cache and a null page cache for file systems that don't use normal methods. Reviewed by: kib
FreeBSD Source:
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FreeBSD
FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.
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), config(8), https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html, and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information, including setting make(1) variables.
Source Roadmap:
bin System/user commands.
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.
sys/<arch>/conf Kernel configuration files. GENERIC is the configuration
used in release builds. NOTES contains documentation of
all possible entries.
tests Regression tests which can be run by Kyua. See tests/README
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tools Utilities for regression testing and miscellaneous tasks.
usr.bin User commands.
usr.sbin System administration commands.
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