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
Commit 7a606f280a allowed the server to do retries of CB_RECALL
callbacks every couple of seconds. This was needed to allow the
Linux client to re-establish the back channel.
However this patch broke the delegation timeout check, such that
it would just keep retrying CB_RECALLS.
If the client has crashed or been network patitioned from the
server, this continues until the client TCP reconnects to
the server and re-establishes the back channel.
This patch modifies the code such that it still times out the
delegation recall after some minutes, so that the server will
allow the conflicting client request once the delegation times out.
This patch only affects the NFSv4 server when delegations are
enabled and a NFSv4 client that holds a delegation has crashed
or been network partitioned from the server for at least several
minutes when a delegation needs to be recalled.
MFC after: 2 weeks
It looks like I've missed a couple of places where we don't clear
stack-allocated CCBs. Don't panic when that happens, just print
a warning.
This is a temporary measure until I get those cases fixed.
Reviewed By: markj
Sponsored by: NetApp, Inc.
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D30296
Some of them were dereferencing the user pointer before disabling SMAP.
PR: 255591
Reviewed by: kib
Tested by: pitwuu@gmail.com
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D30276
m_pullup(9) frees the mbuf(9) chain in the case of an allocation error.
The mbuf chain must not be freed again in this case.
PR: 255874
Submitted by: <lylgood@foxmail.com>
Approved by: markj
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D30273
Previously, daregister() could have been called before dainit()
initialized the UMA zone. This would trip a KASSERT.
Reported By: pho
Tested By: pho
Sponsored by: NetApp, Inc.
Sponsored by: Klara, Inc.
The gfx_fb_drawrect() is drawing rectangle by pixels, this can be very
slow on some systems. Use Blt() video fill primitive instead.
Testing done: Tested on mac mini 2012 where the issue was revealed
Reviewed by: yuripv
MFC after: 1 week
Replace it with a tutorial hosted on kerberos.org and the classic
"dialogue" from Bill Bryant. The change has been reported and
merged upstream (https://github.com/heimdal/heimdal/commit/7f3445f1b7).
MFC after: 3 days
PR: 251854
Reported by: ktullavik@gmail.com
Submitted by: bjk (upstream github)
Reviewed by: bcr
At some places the ASSERT was inserted before variable declarations are
finished. This is fixed now.
Reported by: kib
Reviewed by: kib
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D30282
This patch makes it possible for CAM to use small CCBs allocated
from an periph-specific UMA zone instead of the usual, huge ones.
The end result is that CCBs issued via da(4) take 544B (size of
ccb_scsiio) instead of the usual 2kB (size of 'union ccb', ~1.5kB,
rounded up by malloc(9)). For ATA it's 272B. We waste less
memory, we avoid zeroing the unused 1kB, and it should be easier
to allocate those CCBs in low memory conditions. It should also
be possible to use uma_zone_reserve(9) to improve behaviour
in low memory conditions even further.
Note that this does not change the size, or the layout, of CCBs
as such. CCBs get allocated in various different ways, in particular
on the stack, and I don't want to redo all that. Instead, this
provides an opt-in mechanism for the periph to declare "my start()
callback is fine with receiving a CCB allocated from this UMA zone".
In other words, most of the code works exactly as it used to; the
change only happens to IOs issued by xpt_run_allockq(), which
is - conveniently - pretty much all that matters for performance.
The reason for doing it this way is that it's pretty small, localized
change, and can be implemented gradually and iteratively: take a
periph, make sure its start() callback only casts the CCBs it takes
to a particular type of CCB, for example ccb_scsiio, and that it only
casts CCBs returned by cam_periph_getccb() to that type, then add UMA
zone for that size, and declare it safe to XPT.
This is disabled by default. Set 'kern.cam.ada.enable_uma_ccbs=1'
and 'kern.cam.da.enable_uma_ccbs=1' tunables to enable it. Testing
is welcome; I will flip the default to enable in two weeks from now.
Reviewed By: imp
Sponsored by: NetApp, Inc.
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D28674
The field nullAddress in struct libalias is never set and never used.
It exists as a placeholder for an unused argument only.
Reviewed by: hselasky
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D30253
libalias is a convolut of various coding styles modified by a series
of different editors enforcing interesting convetions on spacing and
comments.
This patch is a baseline to start with a perfomance rework of
libalias. Upcoming patches should be focus on the code, not on the
style. That's why most annoying style errors should be fixed
beforehand.
Reviewed by: hselasky
Discussed by: emaste
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D30259
The HAVE_ZFS macro was dropped from the Makefile during the OpenZFS
merge, bring it back.
While here, drop unused WARNS setting.
PR: 255616
Reported by: Michael Büker <freebsd@michael-bueker.de>
Submitted by: Michael Büker <freebsd@michael-bueker.de>
Fixes: 9e5787d228
Reviewed by: markj
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D30221
The CTL frontend might have provided a buffer that is smaller than the
FirstBurstLength and thus smaller than the amount of unsolicited data
included in the request PDU. Treat these transfers as an empty
transfer.
Reported by: Jithesh Arakkan @ Chelsio
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D29940
A single union ctl_io can be reused across multiple transfers (in
particular by the ramdisk backend). On a reuse, the reservation
pointer would retain its value from the previous transfer tripping an
assertion.
Reported by: Jithesh Arakkan @ Chelsio
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D29939
- Switch to allocating the cxgbei version of icl_pdu explicitly
as a separate refcounted object allocated via malloc/free
instead of storing it in the bhs mbuf prior to the bhs.
- Support the icl_conn_pdu_queue_cb() method to set a callback
on a PDU to be invoked when the PDU is freed.
- For ICL_NOCOPY buffers, use an external mbuf to manage the
storage for the buffer via m_extaddref(). Each external mbuf
holds a reference on the associated PDU, so the callback is
invoked once all of the external mbufs have been freed.
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D29910
- Only allocate 16K jumbo mbufs if the region of data to be
appended is sufficiently large, and use a loop.
- Use m_getm2() to allocate a chain for data less than 16K, or
if m_getjcl() fails.
- Use ENOMEM as the return value instead of '1' if the hook fails due
to a memory allocation error.
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D29909
A CAM target layer I/O CCB can use a S/G list of virtual address ranges
to describe its data buffer. This change adds zero-copy receive support
for such requests.
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D29908
As a result, CPL_FW4_ACK now returns credits for these work requests.
To support this, page pod work requests are now constructed in special
mbufs similar to "raw" mbufs used for NIC TLS in plain TX queues.
These special mbufs are stored in the ulp_pduq and dispatched in order
with PDU work requests.
Sponsored by: Chelsio Communications
Discussed with: np
Differential Revision: https://reviews.freebsd.org/D29904
update_rtm_from_rc() calls update_rtm_from_info() internally.
The latter one may update provided prtm pointer with a new rtm.
Reassign rtm from prtm afeter calling update_rtm_from_info() to
avoid touching the freed rtm.
PR: 255871
Submitted by: lylgood@foxmail.com
MFC after: 3 days
There are some scenarios where a timer event may be detached when it is
on the process' kqueue timer stop queue. If kqtimer_proc_continue() is
called after that point, it will iterate over the queue and access freed
timer structures.
It is also possible, at least in a multithreaded program, for a stopped
timer event to be scheduled without removing it from the process' stop
queue. Ensure that we do not doubly enqueue the event structure in this
case.
Reported by: syzbot+cea0931bb4e34cd728bd@syzkaller.appspotmail.com
Reported by: syzbot+9e1a2f3734652015998c@syzkaller.appspotmail.com
Reviewed by: kib
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30251
Unlike attended installations, scripted installs did not mount non-ZFS
partitions when ZFS root (via zfsboot) was selected. Since this included
the ESP, the EFI loader was not installed. Copy logic from the
attended-install path to make this work.
PR: 255824, 255081
MFC after: 1 week
Obtained from: Mark Huizer
Enabled driver initialization causes an abort
on the NXP LS1028ARDB platform (without any external
endpoints connected). Temporarily disable qoriq_dw_pci
probe, so that to allow successful booting of the OS.
Submitted by: Lukasz Hajec <lha@semihalf.com>
Obtained from: Semihalf
Sponsored by: Alstom Group
Differential Revision: https://reviews.freebsd.org/D30229
We shouldn't overwrite capability register. Instead, voltages supported
by the controller have to be read from dts, as the hardware doesn't
report correct values.
Submitted by: Lukasz Hajec <lha@semihalf.com>
Reviewed by: manu
Obtained from: Semihalf
Sponsored by: Alstom Group
Differential Revision: https://reviews.freebsd.org/D30123
Add a missing call to mmc_fdt_parse, without it some dts properties
are not parsed.
Submitted by: Lukasz Hajec <lha@semihalf.com>
Reviewed by: manu
Obtained from: Semihalf
Sponsored by: Alstom Group
Differential Revision: https://reviews.freebsd.org/D30122
Add data specific for SoC, including all necessary quirks.
Submitted by: Lukasz Hajec <lha@semihalf.com>
Reviewed by: manu
Obtained from: Semihalf
Sponsored by: Alstom Group
Differential Revision: https://reviews.freebsd.org/D30121
If sending out a packet fails during the loop over all links, the
allocated memory is leaked and not all links receive a copy. This
patch fixes those problems, clarifies a premature abort of the loop,
and fixes a minory style(9) bug.
PR: 255430
Submitted by: Dancho Penev
Tested by: Dancho Penev
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D30008
Hint the compiler, that this update is needed at most once per second.
Only in this case the memory line needs to be written. This will
reduce the amount of cache trashing during forward of most frames.
Suggested by: zec
Approved by: zec
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D28601
On x86, the pmu_events table is the source of truth for finding
supported events. However, events not found there may still be present
in the kernel's static event tables. For example, the pmc.soft(3) events
will never be available from pmu-events.
Update pmc_allocate() to search the legacy event tables if
pmc_pmu_pmcallocate() fails to return a result. This allows both event
sources to be consulted before giving up, thus restoring pmc.soft(3) and
pmc.tsc(3) on x86.
Reviewed by: emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30216
This logic was added for handling some of the complicated relationships
between events and x86 CPU models. Since that logic has been mostly
removed from libpmc(3) in favor of pmu-events, this no longer serves
much of a purpose. Mapping CPU types to event tables is already handled
by the switch statement in pmc_init().
Reviewed by: ray, emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30196
All uses of this macro were removed in e92a1350b5. Remove
cpu_has_iaf_counters as well.
Reviewed by: ray, emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30195
