changes in r246417 were incomplete as they did not add explicit calls to
sigdeferstop() around all the places that previously passed SBDRY to
_sleep(). In addition, nfs_getcacheblk() could trigger a write RPC from
getblk() resulting in sigdeferstop() recursing. Rather than manually
deferring stop signals in specific places, change the VFS_*() and VOP_*()
methods to defer stop signals for filesystems which request this behavior
via a new VFCF_SBDRY flag. Note that this has to be a VFC flag rather than
a MNTK flag so that it works properly with VFS_MOUNT() when the mount is
not yet fully constructed. For now, only the NFS clients are set this new
flag in VFS_SET().
A few other related changes:
- Add an assertion to ensure that TDF_SBDRY doesn't leak to userland.
- When a lookup request uses VOP_READLINK() to follow a symlink, mark
the request as being on behalf of the thread performing the lookup
(cnp_thread) rather than using a NULL thread pointer. This causes
NFS to properly handle signals during this VOP on an interruptible
mount.
PR: kern/176179
Reported by: Russell Cattelan (sigdeferstop() recursion)
Reviewed by: kib
MFC after: 1 month
write is a disk write request that tells the disk that the buffer
being written must be committed to the media along with any writes
that preceeded it before any future blocks may be written to the drive.
Barrier writes are provided by adding the functions bbarrierwrite
(bwrite with barrier) and babarrierwrite (bawrite with barrier).
Following a bbarrierwrite the client knows that the requested buffer
is on the media. It does not ensure that buffers written before that
buffer are on the media. It only ensure that buffers written before
that buffer will get to the media before any buffers written after
that buffer. A flush command must be sent to the disk to ensure that
all earlier written buffers are on the media.
Reviewed by: kib
Tested by: Peter Holm
blocking modes described in section 3.4.3 of RFC 2783, allowing the caller
to retrieve the most recent values without blocking, to block for a specified
time, or to block forever.
Reviewed by: discussion on hackers@
now disables read-ahead. It used to effectively restore the system default
readahead hueristic if it had been changed; a negative value now restores
the default.
Reviewed by: kib
every architecture's busdma_machdep.c. It is done by unifying the
bus_dmamap_load_buffer() routines so that they may be called from MI
code. The MD busdma is then given a chance to do any final processing
in the complete() callback.
The cam changes unify the bus_dmamap_load* handling in cam drivers.
The arm and mips implementations are updated to track virtual
addresses for sync(). Previously this was done in a type specific
way. Now it is done in a generic way by recording the list of
virtuals in the map.
Submitted by: jeff (sponsored by EMC/Isilon)
Reviewed by: kan (previous version), scottl,
mjacob (isp(4), no objections for target mode changes)
Discussed with: ian (arm changes)
Tested by: marius (sparc64), mips (jmallet), isci(4) on x86 (jharris),
amd64 (Fabian Keil <freebsd-listen@fabiankeil.de>)
Older entries should be 'before' newer entries in the new buffer too
and there should be no zero-filled gap between them.
Pointed out by: jhb
MFC after: 3 days
X-MFC with: r246282
until child performs exec(). The behaviour is reasonable when a
debugger is the real parent, because the parent is stopped until
exec(), and sending a debugging event to the debugger would deadlock
both parent and child.
On the other hand, when debugger is not the parent of the vforked
child, not sending debugging signals makes it impossible to debug
across vfork.
Fix the issue by declining generating debug signals only when vfork()
was done and child called ptrace(PT_TRACEME). Set a new process flag
P_PPTRACE from the attach code for PT_TRACEME, if P_PPWAIT flag is
set, which indicates that the process was created with vfork() and
still did not execed. Check P_PPTRACE from issignal(), instead of
refusing the trace outright for the P_PPWAIT case. The scope of
P_PPTRACE is exactly contained in the scope of P_PPWAIT.
Found and tested by: zont
Reviewed by: pluknet
MFC after: 2 weeks
Posix requires that open(2) is restartable for SA_RESTART.
For non-posix objects, in particular, devfs nodes, still disable
automatic restart of the opens. The open call to a driver could have
significant side effects for the hardware.
Noted and reviewed by: jilles
Discussed with: bde
MFC after: 2 weeks
cpuset mask for the associated interrupt thread.
The text used above is verbatim from r195249 and the code should now be
in line with the intent of that commit.
195702, 195703, and 195821 prevented a thread from suspending while holding
locks inside of NFS by forcing the thread to fail sleeps with EINTR or
ERESTART but defer the thread suspension to the user boundary. However,
this had the effect that stopping a process during an NFS request could
abort the request and trigger EINTR errors that were visible to userland
processes (previously the thread would have suspended and completed the
request once it was resumed).
This change instead effectively masks stop signals while in the NFS client.
It uses the existing TDF_SBDRY flag to effect this since SIGSTOP cannot
be masked directly. Also, instead of setting PBDRY on individual sleeps,
the NFS client now sets the TDF_SBDRY flag around each NFS request and
stop signals are masked for all sleeps during that region (the previous
change missed sleeps in lockmgr locks). The end result is that stop
signals sent to threads performing an NFS request are completely
ignored until after the NFS request has finished processing and the
thread prepares to return to userland. This restores the behavior of
stop signals being transparent to userland processes while still
preventing threads from suspending while holding NFS locks.
Reviewed by: kib
MFC after: 1 month
Only during very early boot, before malloc(9) is functional (SI_SUB_KMEM),
the static ktr_buf_init is used. Size of the static buffer is determined
by a new kernel option KTR_BOOT_ENTRIES. Its default value is 1024.
This commit builds on top of r243046.
Reviewed by: alc
MFC after: 17 days
And provide kernel compiler version as a sysctl as well.
This is useful while we have gcc and clang cohabitation.
This could be even more useful when we have support
for external toolchains.
In cooperation with: mjg
MFC after: 13 days
in kern_wait6(), which is called by kern_wait(). Remove the redundand
check, introduced in r243136, and add a comment noting this, to make
the code less confusing.
The blank lines are added to properly delineate the scope of the
preceeding comments.
Noted by: "Jukka A. Ukkonen" <jau@iki.fi>
MFC after: 1 week
tunable_mbinit() where it is next to where it is used later.
Change the sysinit level of tunable_mbinit() from SI_SUB_TUNABLES
to SI_SUB_KMEM after the VM is running. This allows to use better
methods to determine the effectively available physical and virtual
memory available to the kernel.
Update comments.
In a second step it can be merged into mbuf_init().
When maxusers was unrestricted and maxfiles was allowed to autotune
much higher the result was that ncallout which was based on maxfiles
and maxproc grew much higher than was needed.
To fix this clip autotuning to the same number we would get with
the old maxusers algorithm which would stop scaling at 384
maxusers.
Growing ncalout higher is not likely to be needed since most consumers
of timeout(9) are gone and any higher value for ncallout causes the
callwheel hashes to be much larger than will even be needed for
most applications.
MFC after: 1 month
Reviewed by: mav
Set the v_hash for a new vnode in the getnewvnode() to the value
calculated based on the vnode structure address. Filesystems using
vfs_hash_insert() override the v_hash using the standard formula of
(inode_number + mnt_hashseed). For other filesystems, the
initialization allows the vfs_hash_index() to provide useful hash too.
Suggested, reviewed and tested by: peter
Sponsored by: The FreeBSD Foundation
MFC after: 5 days
pre-masked hash for the given vnode. The function assumes that
vp->v_hash is initialized by the filesystem vnode instantiation
function. At the moment, it is only done if filesystem uses
vfs_hash_insert().
Reviewed by: peter
Tested by: peter, pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 5 days
mount, which means that is must not be called while the snaplock is
owned. The vfs_write_resume(9) does call the function as the
VFS_SUSP_CLEAN() method, which is too early and falls into the region
still protected by snaplock.
Add yet another flag for the vfs_write_resume_flags() to avoid calling
suspension cleanup handler after the suspend is lifted, and use it in
the ffs_snapshot() call to vfs_write_resume.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
the write start, by adding a variation of the vfs_write_resume(9)
which accepts flags.
Use the new function to prevent a deadlock between parallel suspension
and snapshotting a UFS mount. The ffs_snapshot() code performed
vfs_write_resume() followed by vn_start_write() while owning the
snaplock. If the suspension intervene between resume and
vn_start_write(), the deadlock occured after the suspending thread
tried to lock the snaplock, most typically during the write in the
ffs_copyonwrite().
Reported and tested by: Andreas Longwitz <longwitz@incore.de>
Reviewed by: mckusick
MFC after: 2 weeks
X-MFC-note: make the vfs_write_resume(9) function a macro after the MFC,
in HEAD
case. There is no point in optimizing further the code and use a TRUE
litteral for a path that does heavyweight stuff anyway (like lock acq),
at the price of obfuscated code.
Use the appropriate check where necessary and remove a macro.
Sponsored by: EMC / Isilon storage division
MFC after: 3 days
interrupt context can still be idlethread. At that point, without the
panic condition, it can still happen that idlethread then will try to
acquire some locks to carry on some operations.
Skip the idlethread check on block/sleep lock operations when KDB is
active.
Reported by: jh
Tested by: jh
MFC after: 1 week
When kern_yield() was introduced with the possibility to specify
a new priority, the behaviour changed by not lowering priority at all
in the consumers, making the yielding mechanism highly ineffective for
high priority kthreads like bufdaemon, syncer, vlrudaemon, etc.
There are no evidences that consumers could bear with such change in
semantic and this situation could finally lead to bugs similar to the
ones fixed in r244240.
Re-specify userland pri for kthreads involved.
Tested by: pho
Reviewed by: kib, mdf
MFC after: 1 week
manage a set of power-of-2 sized buffers for bus_dmamem_alloc().
This allows the caller to provide the back-end allocator uma allocator,
allowing full control of the memory pages backing the pool. For
convenience, it provides an optional builtin allocator that provides pages
allocated with the VM_MEMATTR_UNCACHEABLE attribute, for managing pools of
DMA buffers for BUS_DMA_COHERENT or BUS_DMA_NOCACHE.
This also allows the caller to specify a minimum alignment, and it ensures
that all buffers start on a boundary and have a length that's a multiple of
that value, to avoid using buffers that trigger partial cache line flushes.
Submitted by: Ian Lepore <freebsd@damnhippie.dyndns.org>
only returns name, but also vnode of corefile to use.
This simplifies the code and closes few races, especially in %I handling.
Reviewed by: kib
Obtained from: WHEEL Systems
- Use this new format to automatically handle syscalls and VOPs. This
changes the earlier format but is still human readable.
Sponsored by: EMC / Isilon Storage Division
calls and turn it on.
- Do not allow to call them inside jail. [1]
Pointed out by: trasz [1]
Reviewed by: avg
Approved by: kib (mentor)
MFC after: 1 week
This fixed panic where we hold mutex (process lock) and try to obtain sleepable
lock (vnode lock in expand_name()). The panic could occur when %I was used
in kern.corefile.
Additionally we avoid expand_name() overhead when coredumps are disabled.
Obtained from: WHEEL Systems
yields, specify the user priority for the yield. Otherwise, a
higher-priority (kernel) thread could fall into the priority-inversion
with the thread owning the mutex lock.
On single-processor machines or UP kernels, do not loop adaptively
when the next vnode cannot be locked, instead yield unconditionally.
Restructure the iteration initializer and the iterator to remove code
duplication. Put the code to fetch and lock a vnode next to the
current marker, into the mnt_vnode_next_active() function, and use it
instead of repeating the loop.
Reported by: hrs, rmacklem
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
was being copied from the wrong place. This patch fixes that.
This could cause access failures for mapped users, when the group
permissions were needed.
PR: 147998
Submitted by: Christopher Key (cjk32 at cam.ac.uk)
MFC after: 2 weeks
This is an ongoing effort to provide runtime debug information
useful in the field that does not panic existing installations.
This gives us the flexibility needed when shipping images to a
potentially large audience with WITNESS enabled without worrying
about formerly non-fatal LORs hurting a release.
Sponsored by: iXsystems
kern_yield() is problematic than.
The owned mutex is the mount interlock, and it is in fact not needed
to guarantee the stability of the mount list of active vnodes, so fix
the the issue by only taking the mount interlock for MNT_REF and
MNT_REL operations.
While there, augment the unconditional yield by some amount of
spinning [1].
Reported and tested by: pho
Reviewed by: attilio
Submitted by: attilio [1]
MFC after: 3 days
