Commit Graph

258674 Commits

Author SHA1 Message Date
Kirk McKusick
fe815b88b5 Fix fsck_ffs Pass 1b error exit "bad inode number 256 to nextinode".
Pass 1b of fsck_ffs runs only when Pass 1 has found duplicate blocks.
Pass 1 only knows that a block is duplicate when it finds the second
instance of its use. The role of Pass 1b is to find the first use
of all the duplicate blocks. It makes a pass over the cylinder groups
looking for these blocks. When moving to the next cylinder group,
Pass 1b failed to properly calculate the starting inode number for
the cylinder group resulting in the above error message when it
tried to read the first inode in the cylinder group.

Reported by:  Px
Tested by:    Px
PR:           255979
MFC after:    3 days
Sponsored by: Netflix
2021-05-19 14:39:24 -07:00
Warner Losh
71a071be1c bsd-family-tree: Add NetBSD 9.2
NetBSD 9.2 was released on May 12, 2021

Submitted by:		Martin Husemann
Sponsored by:		Netflix
2021-05-19 15:31:47 -06:00
Dmitry Chagin
6560ac57ce tcsh: update to version 6.22.04.
Merge commit '174d8b60324d7e8754709f7155e13ca95220b48c' into main.

MFC After:	2 weeks
2021-05-20 00:12:27 +03:00
Dmitry Chagin
6190ff6104 tcsh: cleanup source tree to reduce diff size.
Remove makefiles, configure files and unused at build time files
to reduce the diff size. Otherwise the diff contains a lot of
unnecessary lines what makes reviewing and merging proccess so hard,
especially for re@.

MFC after:	2 weeks
2021-05-20 00:08:25 +03:00
Poul-Henning Kamp
9c10d00bf8 i2c(8): Add interpreted mode for batch/scripted i2c operations 2021-05-19 18:56:59 +00:00
Poul-Henning Kamp
e32b2bcff0 i2c(8): Change default mode to "transfer", which should work everywhere¹
¹ According to @ian
2021-05-19 18:48:28 +00:00
Poul-Henning Kamp
f4583ebabc i2c(8): Polish: sort switches, dont confuse address & offset 2021-05-19 18:47:32 +00:00
Mateusz Guzik
4fe925b81e fdescfs: allow shared locking of root vnode
Eliminates fdescfs from lock profile when running poudriere.
2021-05-19 17:58:54 +00:00
Mateusz Guzik
43999a5cba pseudofs: use vget_prep + vget_finish instead of vget + the interlock 2021-05-19 17:58:42 +00:00
Warner Losh
086feed850 md5: Create md5sum, etc compatible programs
On Linux, there's a similar set of programs to ours, but that end in the
letters 'sum'. These act basically like FreeBSD versions run with the -r
option. Add code so that when the program ends in 'sum' you get the
linux -r behavior. This is enough to make most things that use sha*sum
work correctly (the -c / --check options, as well as the long args are
not implemented). When running with the -sum programs, ignore -t instead
of running internal speed tests and make -c an error.

Reviewed by:		sef, and kp and allanjude (earlier version)
Relnotes:		yes
Sponsored by:		Netflix
Differential Revision:	https://reviews.freebsd.org/D30309
2021-05-19 11:41:53 -06:00
Alexander Motin
4a6830761c Fix packet cbs/ebs conversion.
Each packet is counted as 128 bytes by the code, not 125.  Not sure
what I was thinking about here 14 years ago.  May be just a typo.

Reported by:	Dmitry Luhtionov <dmitryluhtionov@gmail.com>
MFC after:	2 weeks
2021-05-19 11:04:08 -04:00
Eugene Grosbein
f4b38c360e rc.d: unbreak sysctl lastload
/etc/rc.d/securelevel is supposed to run /etc/rc.d/sysctl lastload
late at boot time to apply /etc/sysctl.conf settings that fail
to apply early. However, this does not work in default configuration
because of kern_securelevel_enable="NO" by default.

Add new script /etc/rc.d/sysctl lastload that starts unconditionally.

Reported by:	Marek Zarychta
MFC after:	1 month
2021-05-19 20:02:31 +07:00
Bjoern A. Zeeb
f0a5e81af4 arm64: rockchip, implement the two rk805/808 clocks
While the xin32k clk was implemented in rk3399_cru as a fixed rate
clock, migrate it to rk805 as we will also need the 2nd clock
'rtc_clko_wifi' for SDIO and BT.
Both clocks remain fixed rate, and while the 1st one is always on
(though that is not expressed in the clk framework), the 2nd one
we can toggle on/off.

Reviewed-by:	manu
Tested-by:	manu
MFC-after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D26870
2021-05-19 11:48:11 +00:00
Peter Holm
7de0aa0135 stress2: Added a new "mdconfig -o force" test scenario 2021-05-19 08:22:09 +02:00
Navdeep Parhar
3965469eaa cxgbe(4): Remove some dead code.
MFC after:	3 days
2021-05-18 23:16:03 -07:00
Rick Macklem
fc0dc94029 nfsd: Reduce the callback timeout to 800msec
Recent discussion on the nfsv4@ietf.org mailing list confirmed
that an NFSv4 server should reply to an RPC in less than 1second.
If an NFSv4 RPC requires a delegation be recalled,
the server will attempt a CB_RECALL callback.
If the client is not responsive, the RPC reply will be delayed
until the callback times out.
Without this patch, the timeout is set to 4 seconds (set in
ticks, but used as seconds), resulting in the RPC reply taking over 4sec.
This patch redefines the constant as being in milliseconds and it
implements that for a value of 800msec, to ensure the RPC
reply is sent in less than 1second.

This patch only affects mounts from clients when delegations
are enabled on the server and the client is unresponsive to callbacks.

MFC after:	2 weeks
2021-05-18 16:17:58 -07:00
Rick Macklem
b3d4c70dc6 nfsd: Add support for CLAIM_DELEG_CUR_FH to the NFSv4.1/4.2 Open
The Linux NFSv4.1/4.2 client now uses the CLAIM_DELEG_CUR_FH
variant of the Open operation when delegations are recalled and
the client has a local open of the file.  This patch adds
support for this variant of Open to the NFSv4.1/4.2 server.

This patch only affects mounts from Linux clients when delegations
are enabled on the server.

MFC after:	2 weeks
2021-05-18 15:53:54 -07:00
Zhenlei Huang
3d846e4822 Do not forward datagrams originated by link-local addresses
The current implement of ip_input() reject packets destined for
169.254.0.0/16, but not those original from 169.254.0.0/16 link-local
addresses.

Fix to fully respect RFC 3927 section 2.7.

PR:		255388
Reviewed by:	donner, rgrimes, karels
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D29968
2021-05-18 22:59:46 +02:00
Markus Stoff
63b6a08ce2 ng_parse: IP address parsing in netgraph eating too many characters
Once the final component of the IP address has been parsed, the offset
on the input must not be advanced, as this would remove an unparsed
character from the input.

Submitted by:	Markus Stoff
Reviewed by:	donner
MFC after:	3 weeks
Differential Revision: https://reviews.freebsd.org/D26489
2021-05-18 22:36:28 +02:00
Lutz Donnerhacke
7fd8baee75 test/libalias: Tests for instantiation
In order to modify libalias for performance, the existing
functionality must not change.  Enforce this.

Reviewed by:	kp
MFC after:	1 week
Differential Revision: https://reviews.freebsd.org/D30307
2021-05-18 22:15:39 +02:00
Lv Yunlong
b295c5ddce socket: Release cred reference later in sodealloc()
We dereference so->so_cred to update the per-uid socket buffer
accounting, so the crfree() call must be deferred until after that
point.

PR:		255869
MFC after:	1 week
2021-05-18 15:25:40 -04:00
Mark Johnston
c4a6258d70 dummynet: Fix mbuf tag allocation failure handling
PR:		255875, 255878, 255879, 255880
Reviewed by:	donner, kp
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D30318
2021-05-18 15:25:16 -04:00
Konstantin Belousov
8cf912b017 ttydev_write: prevent stops while terminal is busied
Since busy state is checked by all blocked writes, stopping a process
which waits in ttydisc_write() causes cascade.  Utilize sigdeferstop()
to avoid the issue.

Submitted by:	Jakub Piecuch <j.piecuch96@gmail.com>
PR:	255816
MFC after:	1 week
2021-05-18 20:52:03 +03:00
Mateusz Guzik
cc6f46ac2f vfs: refactor vdrop
In particular move vunlazy into its own routine.
2021-05-18 15:30:28 +00:00
Mateusz Guzik
715fcc0d34 vfs: change vn_freevnodes_* prefix to idiomatic vfs_freevnodes_* 2021-05-18 15:30:28 +00:00
Hans Petter Selasky
e5ff940a81 Propagate down USB explore error codes, so that failures to enumerate USB HUBs
behind USB HUBs are detected and the USB reset counter logic will kick in
preventing enumeration of continuously failing ports.

Submitted by:	phk@
Tested by:	bz@
PR:		237666
MFC after:	1 week
Sponsored by:	Mellanox Technologies // NVIDIA Networking
2021-05-18 16:11:35 +02:00
Hans Petter Selasky
70ffaaa69c Update USB_PORT_RESET_RECOVERY to comply with the USB 2.0 specification which
says it should be max 10 milliseconds.

This may fix some USB enumeration issues:
> usbd_req_re_enumerate: addr=3, set address failed! (USB_ERR_IOERROR, ignored)
> usbd_setup_device_desc: getting device descriptor at addr 3 failed,

Found by:	Zhichao1.Li@dell.com
MFC after:	1 week
Sponsored by:	Mellanox Technologies // NVIDIA Networking
2021-05-18 15:52:41 +02:00
Hans Petter Selasky
00e501d720 Update usb_timings_sysctl_handler() to accept any value for timings between
0 milliseconds and 2 seconds inclusivly. Some style fixes while at it.

The USB specification has minimum values and maximum values,
and not only minimum values.

MFC after:	1 week
Sponsored by:	Mellanox Technologies // NVIDIA Networking
2021-05-18 15:52:41 +02:00
Roger Pau Monné
9e14ac116e x86/xen: further PVHv1 removal cleanup
The AP startup extern variable declarations are not longer needed,
since PVHv2 uses the native AP startup path using the lapic. Remove
the declaration and make the variables static to mp_machdep.c

Sponsored by: Citrix Systems R&D
2021-05-18 10:43:31 +02:00
Goran Mekić
c232fd4b41 sndstat.4: Improve manpage wording
Reviewed by:    bcr, khng
Differential Revision:	https://reviews.freebsd.org/D30027
2021-05-18 15:40:28 +08:00
Colin Percival
b6be9566d2 Fix buffer overflow in preloaded hostuuid cleaning
When a module of type "hostuuid" is provided by the loader,
prison0_init strips any trailing whitespace and ASCII control
characters by (a) adjusting the buffer length, and (b) zeroing out
the characters in question, before storing it as the system's
hostuuid.

The buffer length adjustment was correct, but the zeroing overwrote
one byte higher in memory than intended -- in the typical case,
zeroing one byte past the end of the hostuuid buffer.  Due to the
layout of buffers passed by the boot loader to the kernel, this will
be the first byte of a subsequent buffer.

This was *probably* harmless; prison0_init runs after preloaded kernel
modules have been linked and after the preloaded /boot/entropy cache
has been processed, so in both cases having the first byte overwritten
will not cause problems.  We cannot however rule out the possibility
that other objects which are preloaded by the loader could suffer from
having the first byte overwritten.

Since the zeroing does not in fact serve any purpose, remove it and
trim trailing whitespace and ASCII control characters by adjusting
the buffer length alone.

Fixes:		c3188289 Preload hostuuid for early-boot use
Reviewed by:	kevans, markj
MFC after:	3 days
2021-05-17 20:07:49 -07:00
Colin Percival
330f110bf1 Fix 'hostuuid: preload data malformed' warning
If the preloaded hostuuid value is invalid and verbose booting is
enabled, a warning is printed.  This printf had two bugs:

1. It was missing a trailing \n character.
2. The malformed UUID is printed with %s even though it is not known
to be NUL-terminated.

This commit adds the missing \n and uses %.*s with the (already known)
length of the preloaded UUID to ensure that we don't read past the end
of the buffer.

Reported by:	kevans
Fixes:		c3188289 Preload hostuuid for early-boot use
MFC after:	3 days
2021-05-17 20:07:49 -07:00
John Baldwin
8d2b4b2e7c cxgbe: Cast pointer arguments to trunc_page() to vm_offset_t.
Reported by:	mjg, jenkins, rmacklem
Fixes:		46bee8043e
Sponsored by:	Chelsio Communications
2021-05-17 17:04:22 -07:00
Kirk McKusick
efe145a745 Correct assert added to dump program.
The dump program was exiting with the message:

Assertion failed: (spcl.c_count + blks < TP_NINDIR), function appendextdata, file /usr/src/sbin/dump/traverse.c, line 759.

The problem arose when dumping external attributes.

This assertion was added in this commit with no review by someone
with expertise in the dump program:

    commit 2d518c6518
    Author:     Warner Losh <imp@FreeBSD.org>
    AuthorDate: Mon Jun 11 19:32:36 2018 +0000
    Commit:     Warner Losh <imp@FreeBSD.org>
    CommitDate: Mon Jun 11 19:32:36 2018 +0000

	Add asserts to prevent overflows of c_addr.

It is clearly wrong as the statement immediately above it in the
code which is deciding if the data will fit is:

	if (spcl.c_count + blks > TP_NINDIR)
		return (0);

As is pointed out in the bug report, the assert should be:

	(spcl.c_count + blks <= TP_NINDIR)

This commit corrects the assert. I am sorry that it took so long to
be brought to my attention and get fixed.

Reported by:  Hampton Finger
PR:           244470
MFC after:    3 days
Sponsored by: Netflix
2021-05-17 16:34:53 -07:00
Eugene Grosbein
f5b5de1a32 ipfw: reload sysctl.conf variables if needed
Currently ipfw has multiple components that are not parts
of GENERIC kernel like dummynet etc. They can bring in important
sysctls if enabled with rc.conf(5) and loaded with ipfw startup script
by means of "required_modules" after initial consult
with /etc/sysctl.conf at boot time. Here is an example of one
increasing limit for dummynet hold queues that defaults to 100:

net.inet.ip.dummynet.pipe_slot_limit=1000

This makes it possible to use ipfw/dummynet rules such as:

ipfw pipe 1 config bw 50Mbit/s queue 1000

Such rule is rejected unless above sysctl is applied.
Another example is a group of net.inet.ip.alias.* sysctls
created after libalias.ko loaded as dependency of ipfw_nat.

This is not a problem if corresponding code compiled in custom kernel
so sysctls exist when sysctl.conf is read early or kernel modules
loaded with a loader. This change makes it work also for GENERIC
and modules loaded by means of rc.conf(5) settings.

MFC after:	1 month
2021-05-18 04:03:15 +07:00
Mark Johnston
4224dbf4c7 xen: Remove leftover bits missed in commit ac3ede5371
Fixes:		ac3ede5371 ("x86/xen: remove PVHv1 code")
Reviewed by:	royger
Differential Revision:	https://reviews.freebsd.org/D30316
2021-05-17 13:06:44 -04:00
Kristof Provost
02c44f40f9 dummynet: Remove unused code
We never set 'busy' and never dequeue from the pending mq. Remove this
code.

Reviewed by:	ae
MFC after:	1 week
Sponsored by:	Rubicon Communications, LLC ("Netgate")
Differential Revision:	https://reviews.freebsd.org/D30313
2021-05-17 15:03:55 +02:00
Kristof Provost
45db385545 pf tests: More set skip on <ifgroup> tests
Test the specific case reported in PR 255852. Clearing the skip flag
on groups was broken because pfctl couldn't work out if a kif was a
group or not, because the kernel no longer set the pfik_group pointer.

PR:		255852
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D30285
2021-05-17 13:48:06 +02:00
Kristof Provost
d69cc04014 pf: Set the pfik_group for userspace
Userspace relies on this pointer to work out if the kif is a group or
not. It can't use it for anything else, because it's a pointer to a
kernel address. Substitute 0xfeedc0de for 'true', so that we don't leak
kernel memory addresses to userspace.

PR:		255852
Reviewed by:	donner
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D30284
2021-05-17 13:48:06 +02:00
Justin Hibbits
b2ee069e8c Fix locking in qoriq_gpio
qoriq_gpio_pin_setflags() locks the device mutex, as does
qoriq_gpio_map_gpios(), causing a recursion on non-recursive lock.  This
was missed during testing for 16e549ebe.
2021-05-17 08:46:45 -05:00
Justin Hibbits
ffd21bd289 Make ISA_206_ATOMICS a kernel option
Summary:
To make it easier to build a kernel with PowerISA 2.06 atomics (sub-word
atomics), add a kernel config option.  User space still needs to specify
it as a CFLAG but that seems easier to do than for the kernel config.

Reviewed By: luporl
Differential Revision: https://reviews.freebsd.org/D29809
2021-05-17 08:46:38 -05:00
Justin Hibbits
7ed09a6778 powerpc: Rework IPI message processing
Summary:
There's no need to use a while loop in the IPI handler, the message list
is cached once and processed.  Instead, since the existing code calls
ffs(), sort the handlers, and use a simple 'if' sequence.

Reviewed By: nwhitehorn
Differential Revision: https://reviews.freebsd.org/D30018
2021-05-17 08:26:40 -05:00
Justin Hibbits
9aad27931e powerpc64/radix mmu: Remove dead variable
Remove dead variable from mmu_radix_extract_and_hold().  Based on
r352408 for amd64.
2021-05-17 08:26:39 -05:00
Roger Pau Monné
ac3ede5371 x86/xen: remove PVHv1 code
PVHv1 was officially removed from Xen in 4.9, so just axe the related
code from FreeBSD.

Note FreeBSD supports PVHv2, which is the replacement for PVHv1.

Sponsored by: Citrix Systems R&D
Reviewed by: kib, Elliott Mitchell
Differential Revision: https://reviews.freebsd.org/D30228
2021-05-17 11:41:21 +02:00
Mitchell Horne
2117a66af5 xen: remove hypervisor_info
This was a source of indirection needed to support PVHv1. Now that that
support has been removed, we can eliminate it.

Reviewed by: royger
2021-05-17 10:56:52 +02:00
Mitchell Horne
c93e6ea344 xen: remove support for PVHv1 bootpath
PVHv1 is a legacy interface supported only by Xen versions 4.4 through
4.9.

Reviewed by: royger
2021-05-17 10:56:52 +02:00
Guangyuan Yang
a44489fb51 Add myself (ygy) as a ports committer
Approved by:	lwhsu (mentor)
Differential Revision:	https://reviews.freebsd.org/D30308
2021-05-16 23:54:25 -04:00
Mark Johnston
60cb98a1bd linux: Fix a mistake in commit fb58045145
The change to futex_andl_smap() should have ordered stac before the
load from a user address, otherwise it does not fix anything.

Fixes:	fb58045145 ("linux: Fix SMAP-enabled futex routines")
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
2021-05-16 22:23:14 -04:00
Mark Johnston
5b81e2e1bc virtio_scsi: Zero stack-allocated CCBs
Fixes:	3394d4239b ("cam: allocate CCBs from UMA for SCSI and ATA IO")
Reported by:	syzbot+2e9ce63919709feb3d1c@syzkaller.appspotmail.com
Reviewed by:	trasz
Sponsored by:	The FreeBSD Foundation
2021-05-16 22:20:39 -04:00
Kirk McKusick
9a2fac6ba6 Fix handling of embedded symbolic links (and history lesson).
The original filesystem release (4.2BSD) had no embedded sysmlinks.
Historically symbolic links were just a different type of file, so
the content of the symbolic link was contained in a single disk block
fragment. We observed that most symbolic links were short enough that
they could fit in the area of the inode that normally holds the block
pointers. So we created embedded symlinks where the content of the
link was held in the inode's pointer area thus avoiding the need to
seek and read a data fragment and reducing the pressure on the block
cache. At the time we had only UFS1 with 32-bit block pointers,
so the test for a fastlink was:

	di_size < (NDADDR + NIADDR) * sizeof(daddr_t)

(where daddr_t would be ufs1_daddr_t today).

When embedded symlinks were added, a spare field in the superblock
with a known zero value became fs_maxsymlinklen. New filesystems
set this field to (NDADDR + NIADDR) * sizeof(daddr_t). Embedded
symlinks were assumed when di_size < fs->fs_maxsymlinklen. Thus
filesystems that preceeded this change always read from blocks
(since fs->fs_maxsymlinklen == 0) and newer ones used embedded
symlinks if they fit. Similarly symlinks created on pre-embedded
symlink filesystems always spill into blocks while newer ones will
embed if they fit.

At the same time that the embedded symbolic links were added, the
on-disk directory structure was changed splitting the former
u_int16_t d_namlen into u_int8_t d_type and u_int8_t d_namlen.
Thus fs_maxsymlinklen <= 0 (as used by the OFSFMT() macro) can
be used to distinguish old directory formats. In retrospect that
should have just been an added flag, but we did not realize we
needed to know about that change until it was already in production.

Code was split into ufs/ffs so that the log structured filesystem could
use ufs functionality while doing its own disk layout. This meant
that no ffs superblock fields could be used in the ufs code. Thus
ffs superblock fields that were needed in ufs code had to be copied
to fields in the mount structure. Since ufs_readlink needed to know
if a link was embedded, fs_maxlinklen gets copied to mnt_maxsymlinklen.

The kernel panic that arose to making this fix was triggered when a
disk error created an inode of type symlink with no allocated data
blocks but a large size. When readlink was called the uiomove was
attempted which segment faulted.

static int
ufs_readlink(ap)
	struct vop_readlink_args /* {
		struct vnode *a_vp;
		struct uio *a_uio;
		struct ucred *a_cred;
	} */ *ap;
{
	struct vnode *vp = ap->a_vp;
	struct inode *ip = VTOI(vp);
	doff_t isize;

	isize = ip->i_size;
	if ((isize < vp->v_mount->mnt_maxsymlinklen) ||
	    DIP(ip, i_blocks) == 0) { /* XXX - for old fastlink support */
		return (uiomove(SHORTLINK(ip), isize, ap->a_uio));
	}
	return (VOP_READ(vp, ap->a_uio, 0, ap->a_cred));
}

The second part of the "if" statement that adds

	DIP(ip, i_blocks) == 0) { /* XXX - for old fastlink support */

is problematic. It never appeared in BSD released by Berkeley because
as noted above mnt_maxsymlinklen is 0 for old format filesystems, so
will always fall through to the VOP_READ as it should. I had to dig
back through `git blame' to find that Rodney Grimes added it as
part of ``The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.''
He must have brought it across from an earlier FreeBSD. Unfortunately
the source-control logs for FreeBSD up to the merger with the
AT&T-blessed 4.4BSD-Lite conversion were destroyed as part of the
agreement to let FreeBSD remain unencumbered, so I cannot pin-point
where that line got added on the FreeBSD side.

The one change needed here is that mnt_maxsymlinklen is declared as
an `int' and should be changed to be `u_int64_t'.

This discovery led us to check out the code that deletes symbolic
links. Specifically

	if (vp->v_type == VLNK &&
	    (ip->i_size < vp->v_mount->mnt_maxsymlinklen ||
	     datablocks == 0)) {
		if (length != 0)
			panic("ffs_truncate: partial truncate of symlink");
		bzero(SHORTLINK(ip), (u_int)ip->i_size);
		ip->i_size = 0;
		DIP_SET(ip, i_size, 0);
		UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
		if (needextclean)
			goto extclean;
		return (ffs_update(vp, waitforupdate));
	}

Here too our broken symlink inode with no data blocks allocated
and a large size will segment fault as we are incorrectly using the
test that we have no data blocks to decide that it is an embdedded
symbolic link and attempting to bzero past the end of the inode.
The test for datablocks == 0 is unnecessary as the test for
ip->i_size < vp->v_mount->mnt_maxsymlinklen will do the right
thing in all cases.

The test for datablocks == 0 was added by David Greenman in this commit:

Author: David Greenman <dg@FreeBSD.org>
Date:   Tue Aug 2 13:51:05 1994 +0000

    Completed (hopefully) the kernel support for old style "fastlinks".

    Notes:
	svn path=/head/; revision=1821

I am guessing that he likely earlier added the incorrect test in the
ufs_readlink code.

I asked David if he had any recollection of why he made this change.
Amazingly, he still had a recollection of why he had made a one-line
change more than twenty years ago. And unsurpisingly it was because
he had been stuck between a rock and a hard place.

FreeBSD was up to 1.1.5 before the switch to the 4.4BSD-Lite code
base. Prior to that, there were three years of development in all
areas of the kernel, including the filesystem code, from the combined
set of people including Bill Jolitz, Patchkit contributors, and
FreeBSD Project members. The compatibility issue at hand was caused
by the FASTLINKS patches from Curt Mayer. In merging in the 4.4BSD-Lite
changes David had to find a way to provide compatibility with both
the changes that had been made in FreeBSD 1.1.5 and with 4.4BSD-Lite.
He felt that these changes would provide compatibility with both systems.

In his words:
``My recollection is that the 'FASTLINKS' symlinks support in
FreeBSD-1.x, as implemented by Curt Mayer, worked differently than
4.4BSD. He used a spare field in the inode to duplicately store the
length. When the 4.4BSD-Lite merge was done, the optimized symlinks
support for existing filesystems (those that were initialized in
FreeBSD-1.x) were broken due to the FFS on-disk structure of
4.4BSD-Lite differing from FreeBSD-1.x. My commit was needed to
restore the backward compatibility with FreeBSD-1.x filesystems.
I think it was the best that could be done in the somewhat urgent
circumstances of the post Berkeley-USL settlement. Also, regarding
Rod's massive commit with little explanation, some context: John
Dyson and I did the initial re-port of the 4.4BSD-Lite kernel to
the 386 platform in just 10 days. It was by far the most intense
hacking effort of my life. In addition to the porting of tons of
FreeBSD-1 code, I think we wrote more than 30,000 lines of new code
in that time to deal with the missing pieces and architectural
changes of 4.4BSD-Lite. We didn't make many notes along the way.
There was a lot of pressure to get something out to the rest of the
developer community as fast as possible, so detailed discrete commits
didn't happen - it all came as a giant wad, which is why Rod's
commit message was worded the way it was.''

Reported by:  Chuck Silvers
Tested by:    Chuck Silvers
History by:   David Greenman Lawrence
MFC after:    1 week
Sponsored by: Netflix
2021-05-16 17:04:11 -07:00