This bug results in data corruption with NFS/TCP. Writes are silently dropped
on EWOULDBLOCK (because socket send buffer is full and sockbuf timer fires).
Reviewed by: ups@
VA_MARK_ATIME feature to fix POSIX conformance fore execve() and mmap(),
we thought that it was optimized well enough for the one file system
that supports it (ffs) and harmless for other file systems (except
layered ones which already get the layering for VOP_SETATTR() wrong).
However, nfs_setattr() doesn't do much parameter checking, so when
it gets a combination of parameters that it doesn't understand, it
always does a Setattr RPC. This RPC can't do anything good, and for
VA_MARK_ATIME it is null except for wasting a lot of time.
This is the smallest and easiest to fix of several bugs that have
increased the number of RPCs for kernel builds on nfs by more than
100% since 2004-11-05. The real-time increase depends on network
latency and parallelization and can also be very large (approaching
the same percentage for unparallelized operations like "make depend"
on systems with fast CPUs and high-latency networks).
sync() and sync_fsync() without losing MNT_ASYNC. Add MNTK_ASYNC flag
which is set only when MNT_ASYNC is set and mnt_noasync is zero, and
check that flag instead of MNT_ASYNC before initiating async io.
adds a FS type specific flag indicating that the FS supports shared
vnode lock lookups, adds some logic in vfs_lookup.c to test this flag
and set lock flags appropriately.
- amd on 6.x is a non-starter (without this change). Using amd under
heavy load results in a deadlock (with cascading vnode locks all the
way to the root) very quickly.
- This change should also fix the more general problem of cascading
vnode deadlocks when an NFS server goes down.
Ideally, we wouldn't need these changes, as enabling shared vnode lock
lookups globally would work. Unfortunately, UFS, for example isn't
ready for shared vnode lock lookups, crashing pretty quickly.
This change is the result of discussions with Stephan Uphoff (ups@).
Reviewed by: ups@
synchronized by the lock on the object containing the page.
Transition PG_WANTED and PG_SWAPINPROG to use the new field,
eliminating the need for holding the page queues lock when setting
or clearing these flags. Rename PG_WANTED and PG_SWAPINPROG to
VPO_WANTED and VPO_SWAPINPROG, respectively.
Eliminate the assertion that the page queues lock is held in
vm_page_io_finish().
Eliminate the acquisition and release of the page queues lock
around calls to vm_page_io_finish() in kern_sendfile() and
vfs_unbusy_pages().
set the MTU prior to mounting root via NFS. This is required if the
server supports a higher than default MTU because the client will not
see the responses otherwise.
MFC after: 3 weeks
soreceive(), and sopoll(), which are wrappers for pru_sosend,
pru_soreceive, and pru_sopoll, and are now used univerally by socket
consumers rather than either directly invoking the old so*() functions
or directly invoking the protocol switch method (about an even split
prior to this commit).
This completes an architectural change that was begun in 1996 to permit
protocols to provide substitute implementations, as now used by UDP.
Consumers now uniformly invoke sosend(), soreceive(), and sopoll() to
perform these operations on sockets -- in particular, distributed file
systems and socket system calls.
Architectural head nod: sam, gnn, wollman
in nfs_strategy. Otherwise, for some buffers, signals would be ignored
at the intr mounts.
Reviewed by: mohan
MFC after: 1 month
Approved by: kan (mentor)
except in places dealing with ifaddr creation or destruction; and
in such special places incomplete ifaddrs should never be linked
to system-wide data structures. Therefore we can eliminate all the
superfluous checks for "ifa->ifa_addr != NULL" and get ready
to the system crashing honestly instead of masking possible bugs.
Suggested by: glebius, jhb, ru
If B_NOCACHE is set the pages of vm backed buffers will be invalidated.
However clean buffers can be backed by dirty VM pages so invalidating them
can lead to data loss.
Add support for flush dirty page in the data invalidation function
of some network file systems.
This fixes data losses during vnode recycling (and other code paths
using invalbuf(*,V_SAVE,*,*)) for data written using an mmaped file.
Collaborative effort by: jhb@,mohans@,peter@,ps@,ups@
Reviewed by: tegge@
MFC after: 7 days
client into the kernel by default, and many users won't use NFS,
don't start an extra 4 kernel threads that are unused. Once NFS
becomes active, it will start nfsiod's as it needs them.
We might consider mandating a minimum iod's equal to the number of
active NFS mounts (truncated to some value), which would force some
to remain available without having to create a new one if the file
system is mostly inactive.
PR: 70880
MFC after: 2 weeks
Prodded by: cel
Head nod: peter
Pointed out by: Joe <fbsd_user at a1poweruser dot com>
mimicing the NFS reference implementation.
NFS over TCP does not need fast retransmit timeouts, since network loss
and congestion are managed by the transport (TCP), unlike with NFS over
UDP. A long timeout prevents the unnecessary retransmission of non-
idempotent NFS requests.
Reviewed by: mohans, silby, rees?
Sponsored by: Network Appliance, Incorporated
the estimator to be more easily tuned and maintained.
There should be no functional change except there is now a lower limit
on the retransmit timeout to prevent the client from retransmitting
faster than the server's disks can fill requests, and an upper limit
to prevent the estimator from taking to long to retransmit during a
server outage.
Reviewed by: mohan, kris, silby
Sponsored by: Network Appliance, Incorporated
vnode after vflush() has succeeded. This would cause a dangling vnode
panic at unmount time otherwise. Other filesystems may have this problem
via their VFS_VGET() routines.
Found by: kris
Sponsored by: Isilon Systems, Inc.
The bug was that earlier, if a request was retransmitted,
we would do subsequent retransmits every 10 msecs.
This can cause data corruption under moderate loads by reordering
operations as seen by the client NFS attribute cache, and on the
server side when the retransmission occurs after the original request
has left the duplicate cache, since the operation will be committed
for a second time.
Further work on retransmission handling is needed (e.g. they are still
being done sent too often since they are scaled by HZ, and the size of
the dup cache is too small and easily overwhelmed on busy servers).
Submitted by: mohans
request, the FreeBSD NFS client will quickly back off to a excessively
long wait (days, then weeks) before retrying the request.
Change the behavior of the FreeBSD NFS client to match the behavior of
the reference NFS client implementation (Solaris). This provides a fixed
delay of 10 seconds between each retry by default. A sysctl, called
nfs3_jukebox_delay, is now available to tune the delay. Unlike Solaris,
the sysctl value on FreeBSD is in seconds, rather than in HZ.
Sponsored by: Network Appliance, Incorporated
Reviewed by: rick
Approved by: silby
MFC after: 3 days
The client's READDIRPLUS logic skips the attributes and
filehandle of the ".." entry. If the server doesn't send
attributes but does send a filehandle for "..", the
client's logic doesn't account for the extra "value
follows" field that indicates whether the filehandle is
present, causing the remaining entries in the reply
to be ignored.
Sponsored by: Network Appliance, Inc.
Reviewed by: rick, mohans
Approved by: silby
MFC after: 2 weeks
last few days. I tracked it down to the fact that nfs_reclaim()
is setting vp->v_data to NULL _before_ calling vnode_destroy_object().
After silence from the mailing list I checked further and discovered
that ufs_reclaim() is unique among FreeBSD filesystems for calling
vnode_destroy_object() early, long before tossing v_data or much
of anything else, for that matter. The rest, including NFS, appear
to be identical, as if they were just clones of one original routine.
The enclosed patch fixes all file systems in essentially the same
way, by moving the call to vnode_destroy_object() to early in the
routine (before the call to vfs_hash_remove(), if any). I have
only tested NFS, but I've now run for over eighteen hours with the
patch where I wouldn't get past four or five without it.
Submitted by: Frank Mayhar
Requested by: Mohan Srinivasan
MFC After: 1 week
event of an error, does the right thing, in terms of setting
the error flags in the buf header. That fixes a crash from
bstrategy().
- Treat ETIMEDOUT as a "recoverable" error, causing the buffer
to be re-dirtied. ETIMEDOUT can occur on soft mounts, when
the number of retries are exceeded, and we don't want data loss
in that case.
Submitted by: Mohan Srinivasan
buffers *and* there are no buffers queued up for writing. The bug
was that NMODIFIED was being cleared even while there were buffers
scheduled to be written out, which leads to all sorts of interesting
bugs - one where the file could shrink (because of a post-op getattr
load, say) causing data in buffer(s) queued for write to be tossed,
resulting in data corruption.
Submitted by: Mohan Srinivasan
