This API has no in-tree consumers at the moment but is useful to at least
one out-of-tree consumer, and naturally complements existing vnode refcount
functions (vholdl(9), vdropl(9)).
Obtained from: kib (sys/ portion)
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D4947
Differential Revision: https://reviews.freebsd.org/D4953
Advance the logical block number to the lblkno of the found block plus
one, instead of incrementing the block number which was used for
lookup. This change skips sparcely populated buffer ranges, similar
to r292325, instead of doing useless lookups.
Do not restart the bnoreuselist() from the start of the range if
buffer lock cannot be obtained without sleep. Only retry lookup and
lock for the same queue and same logical block number.
Reported by: benno
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
buffer for each block number in the range with gbincore(), look up the
next instantiated buffer with the logical block number which is
greater or equal to the next lblkno. This significantly speeds up the
iteration for sparce-populated range.
Move the iteration into new helper bnoreuselist(), which is structured
similarly to flushbuflist().
Reported and tested by: pho
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
the type stability of the buffers memory. Instead of memoizing
pointer to the next buffer and validating it, remember the next
logical block number in the bo list and re-lookup.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
For completeness add a VNASSERT that there are no threads waiting on a
range lock (this was previously checked on every vnode free).
Reported by; Rick Macklem
Fix from: Mateusz Guzik
PR: 204949
on every allocation and fully releases them on every free. These
are not trivial costs: it starts by zeroing a large structure then
initializes a mutex, a lock manager lock, an rw lock, four lists,
and six pointers. And looking at vfs.vnodes_created, these operations
are being done millions of times an hour on a busy machine.
As a performance optimization, this code update uses the uma_init
and uma_fini routines to do these initializations and cleanups only
as the vnodes enter and leave the vnode_zone. With this change the
initializations are only done kern.maxvnodes times at system startup
and then only rarely again. The frees are done only if the vnode_zone
shrinks which never happens in practice. For those curious about the
avoided work, look at the vnode_init() and vnode_fini() functions in
kern/vfs_subr.c to see the code that has been removed from the main
vnode allocation/free path.
Reviewed by: kib
Tested by: Peter Holm
active list, into the header comment for vdrop(), which is the
function that decides whether to leave the vnode on the list. Note
that dirty page write-out in vinactive() is asynchronous.
Discussed with: alc
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
targets. See the comment above wantfreevnodes variable for the
description of the algorithm.
The vfs.vlru_alloc_cache_src sysctl is removed. New code frees
namecache sources as the last chance to satisfy the highest watermark,
instead of selecting the source vnodes randomly. This provides good
enough behaviour to keep vn_fullpath() working in most situations.
The filesystem layout with deep trees, where the removed knob was
required, is thus handled automatically.
Submitted by: bde
Discussed with: mckusick
Tested by: pho
MFC after: 1 month
In poll mode, check for and wake VBAD vnodes. (Vnodes that are VBAD at
registration will never be woken by the RECLAIM trigger.)
Add post-VOP_RECLAIM hook to trigger notes on vnode reclamation. (Vnodes that
were fine at registration but are vgoned while being monitored should signal
waiters.)
Reviewed by: kib
Approved by: markj (mentor)
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D3675
the size of the name cache hash table (mapping file names to vnodes)
and the vnode hash table (mapping mount point and inode number to vnode).
An appropriate locking strategy is the key to changing hash table sizes
while they are in active use.
Reviewed by: kib
Tested by: Peter Holm
Differential Revision: https://reviews.freebsd.org/D2265
MFC after: 2 weeks
reason this didn't result in an unclean shutdown is that devfs ignores
MNT_FORCE flag.
Reviewed by: kib@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3467
It looks like EVFILT_READ and EVFILT_WRITE trigger under the same
conditions as poll()'s POLLRDNORM and POLLWRNORM as described by POSIX.
The only difference is that POLLRDNORM has to be triggered on regular
files unconditionally, whereas EVFILT_READ only triggers when not EOF.
Introduce a new flag, NOTE_FILE_POLL, that can be used to make
EVFILT_READ and EVFILT_WRITE behave identically to poll(). This flag
will be used by cloudlibc's poll() function.
Reviewed by: jmg
Differential Revision: https://reviews.freebsd.org/D3303
Transitions 0->1 and 1->0 (which decide e.g. on putting the vnode on the free
list) of either counter are still guarded with vnode interlock.
Reviewed by: kib (earlier version)
Tested by: pho
Previously vputx would detect the condition and clear the flag.
With this change it is invalid to have both v_usecount > 0 and the flag
set. Assert the condition is met in all revlevant places.
Reviewed by: kib
objects, i.e. for buffer objects which vnode was reclaimed. Buffer
cache cannot write such buffers. Return the error and discard the
buffer immediately on write attempt.
BO_DIRTY now always set during vnode reclamation, since it is used not
only for the INVARIANTS checks. Do allow placement of the clean
buffers on dead bufobj list, otherwise filesystems cannot use bufcache
at all after the devvp reclaim.
Reported and tested by: trasz
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
the active vnode list for the given mount point, with the assumption
that vnodes with dirty pages are active. This is enforced by
vinactive() doing vm_object_page_clean() pass over the vnode pages.
The issue is, if vinactive() cannot be called during vput() due to the
vnode being only shared-locked, we might end up with the dirty pages
for the vnode on the free list. Such vnode is invisible to syncer,
and pages are only cleaned on the vnode reactivation. In other words,
the race results in the broken guarantee that user data, written
through the mmap(2), is written to the disk not later than in 30
seconds after the write.
Fix this by keeping the vnode which is freed but still owing
inactivation, on the active list. When syncer loops find such vnode,
it is deactivated and cleaned by the final vput() call.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Nothing stops a parallel unmount to suceed before the given call to
dounmount() checks and locks the covered vnode. Prevent dounmount()
from acting on the freed (although type-stable) memory by changing the
interface to require the mount point to be referenced. dounmount()
consumes the reference on return, regardless of the sucessfull or
erronous result.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
use VOP_FSYNC() to perform the NFS server's Commit operation.
This patch adds a mnt_kern_flag called MNTK_USES_BCACHE which
is set by file systems that use the buffer cache. If this flag
is not set, the NFS server always does a VOP_FSYNC().
This should be ok for old file system modules that do not set
MNTK_USES_BCACHE, since calling VOP_FSYNC() is correct, although
it might not be optimal for file systems that use the buffer cache.
Reviewed by: kib
MFC after: 2 weeks
prevent errors from yanking devices out from under filesystems. Only
care about special vnodes on devfs, special nodes on other kinds of
filesystems do not have special properties.
Sponsored by: EMC / Isilon Storage Division
Submitted by: Conrad Meyer
MFC after: 1 week
- vfs.recycles counts the number of vnodes forcefully recycled to avoid
exceeding kern.maxvnodes.
- vfs.vnodes_created counts the number of vnodes created by successful
calls to getnewvnode().
Differential Revision: https://reviews.freebsd.org/D1671
Reviewed by: kib
MFC after: 1 week
creating delayed write buffers belonging to the reclaimed vnode. Put
the buffer cleanup code after inactivation.
Add asserts that ensure that buffer queues are empty and add BO_DEAD
flag for bufobj to check that no buffers are added after the cleanup.
BO_DEAD is only used by INVARIANTS-enabled kernels.
Reported and tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
to be called before suspension and after resume, correspondingly. The
syncer_suspend() ensures that all filesystems dirty data and metadata
are saved to the permanent storage, and stops kernel threads which
might modify filesystems. The syncer_resume() restores stopped
threads.
For now, only syncer is stopped. This is needed, because each sync
loop causes superblock updates for UFS.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Some watchdog drivers (like ipmi) need to sleep while patting the watchdog.
See sys/dev/ipmi/ipmi.c:ipmi_wd_event(), which calls malloc(M_WAITOK).
Submitted by: asomers
MFC after: 1 month
Sponsored by: Spectra Logic
MFSpectraBSD: 637548 on 2012/10/04
It could be claimed that two things were reasonable protected by
Giant. One is vfsconf list links, which is converted to the new
dedicated sx vfsconf_sx. Another is vfsconf.vfc_refcount, which is
now updated with atomics.
Note that vfc_refcount still has the same races now as it has under
the Giant, the unload of filesystem modules can happen while the
module is still in use.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
some parts of the checks are in fact redundand in the surrounding
code, and it is more clear what the conditions are by direct testing
of the flags. Two of the three macros were only used in assertions.
In vnlru_free(), all relevant parts of vholdl() were already inlined,
except the increment of v_holdcnt itself. Do not call vholdl() to do
the increment as well, this allows to make assertions in
vholdl()/vhold() more strict.
In v_incr_usecount(), call vholdl() before incrementing other ref
counters. The change is no-op, but it makes less surprising to see
the vnode state in debugger if interrupted inside v_incr_usecount().
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
avoid congestion on global mountlist_mtx mutex in vfs_busyfs(), while
traversing through the list of mount points.
This change significantly improves NFS server scalability, since it had
to do this translation for every request, and the global lock becomes quite
congested.
This code is more optimized for relatively small number of mount points.
On systems with hundreds of active mount points this simple cache may have
many collisions. But the original traversal code in that case should also
behave much worse, so we are not loosing much.
Reviewed by: attilio
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
This allows to mostly avoid lock usage in getnewvnode_[drop_]reserve(),
that reduces number of global vnode_free_list_mtx mutex acquisitions
from 4 to 2 per NFS request on ZFS, improving SMP scalability.
Reviewed by: kib
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
Assert that the hold count has not fallen below the use count, a situation
that would only happen when a vref() (or similar) is erroneously paired
with a vdrop(). This situation has not been observed in the wild, but
could be helpful for someone implementing a new filesystem.
Reviewed by: kib
Approved by: hrs (mentor)
To reduce the diff struct pcu.cnt field was not renamed, so
PCPU_OP(cnt.field) is still used. pc_cnt and pcpu are also used in
kvm(3) and vmstat(8). The goal was to not affect externally used KPI.
Bump __FreeBSD_version_ in case some out-of-tree module/code relies on the
the global cnt variable.
Exp-run revealed no ports using it directly.
No objection from: arch@
Sponsored by: EMC / Isilon Storage Division
really belong to it. Such vnodes, with the pointers to other vnodes
v_objects, are typically instantiated by the bypass filesystems.
Invalidating mappings of other vnode pages and the pages is wrong,
since reclamation of the upper vnode does not imply that lower vnode
is reclaimed too.
One of the consequences of the improper reclamation was destruction of
the wired mappings of the lower vnode pages, triggering miscellaneous
assertions in the VM system.
Reported by: John Marshall <john.marshall@riverwillow.com.au>
Tested by: John Marshall <john.marshall@riverwillow.com.au>, pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Approved by: re (gjb)
with the vnode shared-locked. If upgrade succeeded, the inactivation
can be done immediately, instead of being postponed.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Approved by: re (glebius)
Otherwise, knote keeps a pointer to a vnode which could become invalid
any time.
Reported by: many
Tested by: Patrick Lamaiziere <patfbsd@davenulle.org>
Discussed with: jmg
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Approved by: re (marius)
