freebsd kernel with SKQ
fd7c4230b2
part of fixing msdosfs for large sector sizes. One of the fixed bugs was fatal for large sector sizes. 1. The fsinfo block has size 512, but it was misunderstood and declared as having size 1024, with nothing in the second 512 bytes except a signature at the end. The second 512 bytes actually normally (if the file system was created by Windows) consist of a second boot sector which is normally (in WinXP) empty except for a signature -- the normal layout is one boot sector, one fsinfo sector, another boot sector, then these 3 sectors duplicated. However, other layouts are valid. newfs_msdos produces a valid layout with one boot sector, one fsinfo sector, then these 2 sectors duplicated. The signature check for the extra part of the fsinfo was thus normally checking the signature in either the second boot sector or the first boot sector in the copy, and thus accidentally succeeding. The extra signature check would just fail for weirder layouts with 512-byte sectors, and for normal layouts with any other sector size. Remove the extra bytes and the extra signature check. 2. Old versions did i/o to the fsinfo block using size 1024, with the second half only used for the extra signature check on read. This was harmless for sector size 512, and worked accidentally for sector size 1024. The i/o just failed for larger sector sizes. The version being fixed did i/o to the fsinfo block using size fsi_size(pmp) = (1024 << ((pmp)->pm_BlkPerSec >> 2)). This expression makes no sense. It happens to work for sector small sector sizes, but for sector size 32K it gives the preposterous value of 64M and thus causes panics. A sector size of 32768 is necessary for at least some DVD-RW's (where the minimum write size is 32768 although the minimum read size is 2048). Now that the size of the fsinfo block is 512, it always fits in one sector so there is no need for a macro to express it. Just use the sector size where the old code uses 1024. Approved by: re (kensmith) Approved by: nyan (several years ago for a different version of (2)) |
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| bin | ||
| cddl | ||
| compat/opensolaris | ||
| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| ObsoleteFiles.inc | ||
| README | ||
| UPDATING | ||
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, the most commonly used one being ``world'', which rebuilds and installs everything in the FreeBSD system from the source tree except the kernel, the kernel-modules and the contents of /etc. The ``world'' target should only be used in cases where the source tree has not changed from the currently running version. See: http://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, documentation for which can be found at: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html And in the config(8) man page. 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 sample kernel configuration files reside in the sys/<arch>/conf sub-directory (assuming that you've installed the kernel sources), the file named GENERIC being the one used to build your initial installation kernel. The file NOTES contains entries and documentation for all possible devices, not just those commonly used. It is the successor of the ancient LINT file, but in contrast to LINT, it is not buildable as a kernel but a pure reference and documentation file. Source Roadmap: --------------- bin System/user commands. contrib Packages contributed by 3rd parties. crypto Cryptography stuff (see crypto/README). etc Template files for /etc. games Amusements. 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. sys Kernel sources. tools Utilities for regression testing and miscellaneous tasks. usr.bin User commands. usr.sbin System administration commands. For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html