Commit Graph

1049 Commits

Author SHA1 Message Date
Alan Cox
396b3e34b4 Avoid an exclusive acquisition of the object lock on the expected execution
path through the NFS clients' getpages functions.

Introduce vm_pager_free_nonreq().  This function can be used to eliminate
code that is duplicated in many getpages functions.  Also, in contrast to
the code that currently appears in those getpages functions,
vm_pager_free_nonreq() avoids acquiring an exclusive object lock in one
case.

Reviewed by:	kib
MFC after:	6 weeks
Sponsored by:	EMC / Isilon Storage Division
2014-09-14 18:07:55 +00:00
Rick Macklem
cf766161ff For software builds, the NFS client does many small
synchronous (with FILE_SYNC) writes because non-contiguous
byte ranges in the same buffer cache block are being
written. This patch adds a new mount option "noncontigwr"
which allows the non-contiguous byte ranges to be combined,
with the dirty byte range becoming the superset of the bytes
that are dirty, if the file has not been file locked.
This reduces the number of writes significantly for software
builds. The only case where this change might break existing
applications is where an application is writing
non-overlapping byte ranges within the same buffer cache block
of a file from multiple clients concurrently.
Since such an application would normally do file locking on
the file, avoiding the byte range merge for files that have
been file locked should be sufficient for most (maybe all?) cases.

Submitted by:	jhb (earlier version)
Reviewed by:	kib
MFC after:	3 weeks
2013-12-07 23:05:59 +00:00
Attilio Rao
54366c0bd7 - For kernel compiled only with KDTRACE_HOOKS and not any lock debugging
option, unbreak the lock tracing release semantic by embedding
  calls to LOCKSTAT_PROFILE_RELEASE_LOCK() direclty in the inlined
  version of the releasing functions for mutex, rwlock and sxlock.
  Failing to do so skips the lockstat_probe_func invokation for
  unlocking.
- As part of the LOCKSTAT support is inlined in mutex operation, for
  kernel compiled without lock debugging options, potentially every
  consumer must be compiled including opt_kdtrace.h.
  Fix this by moving KDTRACE_HOOKS into opt_global.h and remove the
  dependency by opt_kdtrace.h for all files, as now only KDTRACE_FRAMES
  is linked there and it is only used as a compile-time stub [0].

[0] immediately shows some new bug as DTRACE-derived support for debug
in sfxge is broken and it was never really tested.  As it was not
including correctly opt_kdtrace.h before it was never enabled so it
was kept broken for a while.  Fix this by using a protection stub,
leaving sfxge driver authors the responsibility for fixing it
appropriately [1].

Sponsored by:	EMC / Isilon storage division
Discussed with:	rstone
[0] Reported by:	rstone
[1] Discussed with:	philip
2013-11-25 07:38:45 +00:00
Gleb Smirnoff
76039bc84f The r48589 promised to remove implicit inclusion of if_var.h soon. Prepare
to this event, adding if_var.h to files that do need it. Also, include
all includes that now are included due to implicit pollution via if_var.h

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
2013-10-26 17:58:36 +00:00
Rick Macklem
913df8fd72 A problem with the old NFS client where large writes to large files
would sometimes result in a corrupted file was reported via email.
This problem appears to have been caused by r251719 (reverting
r251719 fixed the problem). Although I have not been able to
reproduce this problem, I suspect it is caused by another thread
increasing np->n_size after the mtx_unlock(&np->n_mtx) but before
the vnode_pager_setsize() call. Since the np->n_mtx mutex serializes
updates to np->n_size, doing the vnode_pager_setsize() with the
mutex locked appears to avoid the problem.
Unfortunately, vnode_pager_setsize() where the new size is smaller,
cannot be called with a mutex held.
This patch returns the semantics to be close to pre-r251719 such that the
call to the vnode_pager_setsize() is only delayed until after the mutex is
unlocked when np->n_size is shrinking. Since the file is growing
when being written, I believe this will fix the corruption.

Reported by:	David G. Lawrence (dg@dglawrence.com)
Tested by:	David G. Lawrence (pending, to happen soon)
Reviewed by:	kib
MFC after:	1 week
2013-07-04 00:54:23 +00:00
Rick Macklem
28be5427f1 A recent version of the oldnfs NFS client in head/current
will crash when doing a large write, since m_get2() would
return NULL. This patch fixes the problem, since nfsm_uiotombuf()
will allocate additional mbufs, as required.

Reported by:	sbruno
Tested by:	sbruno
Discussed with:	glebius
2013-07-01 21:16:19 +00:00
Jeff Roberson
22a722605d - Convert the bufobj lock to rwlock.
- Use a shared bufobj lock in getblk() and inmem().
 - Convert softdep's lk to rwlock to match the bufobj lock.
 - Move INFREECNT to b_flags and protect it with the buf lock.
 - Remove unnecessary locking around bremfree() and BKGRDINPROG.

Sponsored by:	EMC / Isilon Storage Division
Discussed with:	mckusick, kib, mdf
2013-05-31 00:43:41 +00:00
Rick Macklem
4562199350 Add a patch analygous to r248567, r248581, r251079 to the
old NFS client to avoid the panic reported in the PR by
doing the vnode_pager_setsize() call after unlocking the mutex.

PR:		177335
MFC after:	2 weeks
2013-05-29 00:32:49 +00:00
Rick Macklem
64a0e848ab When an NFS unmount occurs, once vflush() writes the last dirty
buffer for the last vnode on the mount back to the server, it
returns. At that point, the code continues with the unmount,
including freeing up the nfs specific part of the mount structure.
It is possible that an nfsiod thread will try to check for an
empty I/O queue in the nfs specific part of the mount structure
after it has been free'd by the unmount. This patch avoids this problem by
setting the iodmount entries for the mount back to NULL while holding the
mutex in the unmount and checking the appropriate entry is non-NULL after
acquiring the mutex in the nfsiod thread.

Reported and tested by:	pho
Reviewed by:	kib
MFC after:	2 weeks
2013-04-18 23:20:16 +00:00
Rick Macklem
175b3f31d3 Both NFS clients can deadlock when using the "rdirplus" mount
option. This can occur when an nfsiod thread that already holds
a buffer lock attempts to acquire a vnode lock on an entry in
the directory (a LOR) when another thread holding the vnode lock
is waiting on an nfsiod thread. This patch avoids the deadlock by disabling
readahead for this case, so the nfsiod threads never do readdirplus.
Since readaheads for directories need the directory offset cookie
from the previous read, they cannot normally happen in parallel.
As such, testing by jhb@ and myself didn't find any performance
degredation when this patch is applied. If there is a case where
this results in a significant performance degradation, mounting
without the "rdirplus" option can be done to re-enable readahead
for directories.

Reported and tested by:	jhb
Reviewed by:	jhb
MFC after:	2 weeks
2013-04-18 13:09:04 +00:00
Ed Maste
96ecfd9813 Fix remainder calculation when biosize is not a power of 2
In common configurations biosize is a power of two, but is not required to
be so.  Thanks to markj@ for spotting an additional case beyond my original
patch.

Reviewed by: rmacklem@
2013-03-19 13:06:11 +00:00
John Baldwin
3b14c753ff Revert 195703 and 195821 as this special stop handling in NFS is now
implemented via VFCF_SBDRY rather than passing PBDRY to individual
sleep calls.
2013-03-13 21:06:03 +00:00
Gleb Smirnoff
41a7572b26 Functions m_getm2() and m_get2() have different order of arguments,
and that can drive someone crazy. While m_get2() is young and not
documented yet, change its order of arguments to match m_getm2().

Sorry for churn, but better now than later.
2013-03-12 13:42:47 +00:00
Gleb Smirnoff
8e7e03d327 - Use m_get2() instead of nfsm_reqhead().
- Use m_get(), m_getcl() instead of historic macros.

Sponsored by:	Nginx, Inc.
2013-03-12 12:23:47 +00:00
Attilio Rao
89f6b8632c Switch the vm_object mutex to be a rwlock. This will enable in the
future further optimizations where the vm_object lock will be held
in read mode most of the time the page cache resident pool of pages
are accessed for reading purposes.

The change is mostly mechanical but few notes are reported:
* The KPI changes as follow:
  - VM_OBJECT_LOCK() -> VM_OBJECT_WLOCK()
  - VM_OBJECT_TRYLOCK() -> VM_OBJECT_TRYWLOCK()
  - VM_OBJECT_UNLOCK() -> VM_OBJECT_WUNLOCK()
  - VM_OBJECT_LOCK_ASSERT(MA_OWNED) -> VM_OBJECT_ASSERT_WLOCKED()
    (in order to avoid visibility of implementation details)
  - The read-mode operations are added:
    VM_OBJECT_RLOCK(), VM_OBJECT_TRYRLOCK(), VM_OBJECT_RUNLOCK(),
    VM_OBJECT_ASSERT_RLOCKED(), VM_OBJECT_ASSERT_LOCKED()
* The vm/vm_pager.h namespace pollution avoidance (forcing requiring
  sys/mutex.h in consumers directly to cater its inlining functions
  using VM_OBJECT_LOCK()) imposes that all the vm/vm_pager.h
  consumers now must include also sys/rwlock.h.
* zfs requires a quite convoluted fix to include FreeBSD rwlocks into
  the compat layer because the name clash between FreeBSD and solaris
  versions must be avoided.
  At this purpose zfs redefines the vm_object locking functions
  directly, isolating the FreeBSD components in specific compat stubs.

The KPI results heavilly broken by this commit.  Thirdy part ports must
be updated accordingly (I can think off-hand of VirtualBox, for example).

Sponsored by:	EMC / Isilon storage division
Reviewed by:	jeff
Reviewed by:	pjd (ZFS specific review)
Discussed with:	alc
Tested by:	pho
2013-03-09 02:32:23 +00:00
John Baldwin
593efaf9f7 Further refine the handling of stop signals in the NFS client. The
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
2013-02-21 19:02:50 +00:00
John Baldwin
a120a7a3cd Rework the handling of stop signals in the NFS client. The changes in
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
2013-02-06 17:06:51 +00:00
John Baldwin
a89a2c8ba4 Further cleanups to use of timestamps in NFS:
- Use NFSD_MONOSEC (which maps to time_uptime) instead of the seconds
  portion of wall-time stamps to manage timeouts on events.
- Remove unused nd_starttime from the per-request structure in the new
  NFS server.
- Use nanotime() for the modification time on a delegation to get as
  precise a time as possible.
- Use time_second instead of extracting the second from a call to
  getmicrotime().

Submitted by:	bde (3)
Reviewed by:	bde, rmacklem
MFC after:	2 weeks
2013-01-25 15:25:24 +00:00
John Baldwin
d177f14da9 Use vfs_timestamp() to set file timestamps rather than invoking
getmicrotime() or getnanotime() directly in NFS.

Reviewed by:	rmacklem, bde
MFC after:	1 week
2013-01-18 18:43:38 +00:00
John Baldwin
5055536eec Use the VA_UTIMES_NULL flag to detect when NULL was passed to utimes()
instead of comparing the desired time against the current time as a
heuristic.

Reviewed by:	rmacklem
MFC after:	1 week
2013-01-16 21:52:31 +00:00
John Baldwin
6910d7a0d8 - More properly handle interrupted NFS requests on an interruptible mount
by returning an error of EINTR rather than EACCES.
- While here, bring back some (but not all) of the NFS RPC statistics lost
  when krpc was committed.

Reviewed by:	rmacklem
MFC after:	1 week
2013-01-15 22:08:17 +00:00
Rick Macklem
1f60bfd822 Move the NFSv4.1 client patches over from projects/nfsv4.1-client
to head. I don't think the NFS client behaviour will change unless
the new "minorversion=1" mount option is used. It includes basic
NFSv4.1 support plus support for pNFS using the Files Layout only.
All problems detecting during an NFSv4.1 Bakeathon testing event
in June 2012 have been resolved in this code and it has been tested
against the NFSv4.1 server available to me.
Although not reviewed, I believe that kib@ has looked at it.
2012-12-08 22:52:39 +00:00
Gleb Smirnoff
eb1b1807af Mechanically substitute flags from historic mbuf allocator with
malloc(9) flags within sys.

Exceptions:

- sys/contrib not touched
- sys/mbuf.h edited manually
2012-12-05 08:04:20 +00:00
Attilio Rao
c6e0355cee r16312 is not any longer real since many years (likely since when VFS
received granular locking) but the comment present in UFS has been
copied all over other filesystems code incorrectly for several times.

Removes comments that makes no sense now.

Reviewed by:	kib
MFC after:	3 days
2012-11-19 22:43:45 +00:00
Attilio Rao
bc2258da88 Complete MPSAFE VFS interface and remove MNTK_MPSAFE flag.
Porters should refer to __FreeBSD_version 1000021 for this change as
it may have happened at the same timeframe.
2012-11-09 18:02:25 +00:00
Konstantin Belousov
b6c00483e9 Do not leave invalid pages in the object after the short read for a
network file systems (not only NFS proper). Short reads cause pages
other then the requested one, which were not filled by read response,
to stay invalid.

Change the vm_page_readahead_finish() interface to not take the error
code, but instead to make a decision to free or to (de)activate the
page only by its validity. As result, not requested invalid pages are
freed even if the read RPC indicated success.

Noted and reviewed by:	alc
MFC after:	1 week
2012-08-14 11:45:47 +00:00
Konstantin Belousov
1c771f9222 After the PHYS_TO_VM_PAGE() function was de-inlined, the main reason
to pull vm_param.h was removed.  Other big dependency of vm_page.h on
vm_param.h are PA_LOCK* definitions, which are only needed for
in-kernel code, because modules use KBI-safe functions to lock the
pages.

Stop including vm_param.h into vm_page.h. Include vm_param.h
explicitely for the kernel code which needs it.

Suggested and reviewed by:	alc
MFC after:    2 weeks
2012-08-05 14:11:42 +00:00
Konstantin Belousov
0055cbd3c5 Reduce code duplication and exposure of direct access to struct
vm_page oflags by providing helper function
vm_page_readahead_finish(), which handles completed reads for pages
with indexes other then the requested one, for VOP_GETPAGES().

Reviewed by:	alc
MFC after:	1 week
2012-08-04 18:16:43 +00:00
Rick Macklem
7af1242a34 PR# 165923 reported intermittent write failures for dirty
memory mapped pages being written back on an NFS mount.
Since any thread can call VOP_PUTPAGES() to write back a
dirty page, the credentials of that thread may not have
write access to the file on an NFS server. (Often the uid
is 0, which may be mapped to "nobody" in the NFS server.)
Although there is no completely correct fix for this
(NFS servers check access on every write RPC instead of at
open/mmap time), this patch avoids the common cases by
holding onto a credential that recently opened the file
for writing and uses that credential for the write RPCs
being done by VOP_PUTPAGES() for both NFS clients.

Tested by:	Joel Ray Holveck (joelh at juniper.net)
PR:		kern/165923
Reviewed by:	kib
MFC after:	2 weeks
2012-05-12 12:02:51 +00:00
Kirk McKusick
550da26ab1 Fix mount mutex handling missed in r234386. 2012-05-10 21:38:48 +00:00
Sergey Kandaurov
54d642ad7d Fix mount mutex handling missed in r234386. 2012-05-05 09:34:35 +00:00
Edward Tomasz Napierala
c52fd858ae Remove unused thread argument from vtruncbuf().
Reviewed by:	kib
2012-04-23 13:21:28 +00:00
Kirk McKusick
71469bb38f Replace the MNT_VNODE_FOREACH interface with MNT_VNODE_FOREACH_ALL.
The primary changes are that the user of the interface no longer
needs to manage the mount-mutex locking and that the vnode that
is returned has its mutex locked (thus avoiding the need to check
to see if its is DOOMED or other possible end of life senarios).

To minimize compatibility issues for third-party developers, the
old MNT_VNODE_FOREACH interface will remain available so that this
change can be MFC'ed to 9. Following the MFC to 9, MNT_VNODE_FOREACH
will be removed in head.

The reason for this update is to prepare for the addition of the
MNT_VNODE_FOREACH_ACTIVE interface that will loop over just the
active vnodes associated with a mount point (typically less than
1% of the vnodes associated with the mount point).

Reviewed by: kib
Tested by:   Peter Holm
MFC after:   2 weeks
2012-04-17 16:28:22 +00:00
Konstantin Belousov
b80dcb55aa Remove fifo.h. The only used function declaration from the header is
migrated to sys/vnode.h.

Submitted by:	gianni
2012-03-11 12:19:58 +00:00
Rick Macklem
5e99212d36 Post r230394, the Lookup RPC counts for both NFS clients increased
significantly. Upon investigation this was caused by name cache
misses for lookups of "..". For name cache entries for non-".."
directories, the cache entry serves double duty. It maps both the
named directory plus ".." for the parent of the directory. As such,
two ctime values (one for each of the directory and its parent) need
to be saved in the name cache entry.
This patch adds an entry for ctime of the parent directory to the
name cache. It also adds an additional uma zone for large entries
with this time value, in order to minimize memory wastage.
As well, it fixes a couple of cases where the mtime of the parent
directory was being saved instead of ctime for positive name cache
entries. With this patch, Lookup RPC counts return to values similar
to pre-r230394 kernels.

Reported by:	bde
Discussed with:	kib
Reviewed by:	jhb
MFC after:	2 weeks
2012-03-03 01:06:54 +00:00
Rick Macklem
4cf7d12840 Fix the NFS clients so that they use copyin() instead of bcopy(),
when doing direct I/O. This direct I/O code is not enabled by default.

Submitted by:	kib (earlier version)
Reviewed by:	kib
MFC after:	1 week
2012-03-01 03:53:07 +00:00
John Baldwin
52c746eacc Adjust the nfs_skip_wcc_data_onerr setting so that it does not block
post-op attributes for ENOENT errors now that the name caching logic
depends on working post-op attributes.

MFC after:	2 weeks
2012-02-24 17:26:06 +00:00
Konstantin Belousov
526d0bd547 Fix found places where uio_resid is truncated to int.
Add the sysctl debug.iosize_max_clamp, enabled by default. Setting the
sysctl to zero allows to perform the SSIZE_MAX-sized i/o requests from
the usermode.

Discussed with:	bde, das (previous versions)
MFC after:	1 month
2012-02-21 01:05:12 +00:00
Bjoern A. Zeeb
9dba179d5e IFC @231845
Sponsored by:	Cisco Systems, Inc.
2012-02-17 00:27:48 +00:00
John Baldwin
bf40d24a3f Rename cache_lookup_times() to cache_lookup() and retire the old API and
ABI stub for cache_lookup().
2012-02-06 17:00:28 +00:00
Konstantin Belousov
c480f781ea Current implementations of sync(2) and syncer vnode fsync() VOP uses
mnt_noasync counter to temporary remove MNTK_ASYNC mount option, which
is needed to guarantee a synchronous completion of the initiated i/o
before syscall or VOP return.  Global removal of MNTK_ASYNC option is
harmful because not only i/o started from corresponding thread becomes
synchronous, but all i/o is synchronous on the filesystem which is
initiated during sync(2) or syncer activity.

Instead of removing MNTK_ASYNC from mnt_kern_flag, provide a local
thread flag to disable async i/o for current thread only. Use the
opportunity to move DOINGASYNC() macro into sys/vnode.h and
consistently use it through places which tested for MNTK_ASYNC.

Some testing demonstrated 60-70% improvements in run time for the
metadata-intensive operations on async-mounted UFS volumes, but still
with great deviation due to other reasons.

Reviewed by:	mckusick
Tested by:	scottl
MFC after:	2 weeks
2012-02-06 11:04:36 +00:00
Bjoern A. Zeeb
81d5d46b3c Add multi-FIB IPv6 support to the core network stack supplementing
the original IPv4 implementation from r178888:

- Use RT_DEFAULT_FIB in the IPv4 implementation where noticed.
- Use rt*fib() KPI with explicit RT_DEFAULT_FIB where applicable in
  the NFS code.
- Use the new in6_rt* KPI in TCP, gif(4), and the IPv6 network stack
  where applicable.
- Split in6_rtqtimo() and in6_mtutimo() as done in IPv4 and equally
  prevent multiple initializations of callouts in in6_inithead().
- Use wrapper functions where needed to preserve the current KPI to
  ease MFCs.  Use BURN_BRIDGES to indicate expected future cleanup.
- Fix (related) comments (both technical or style).
- Convert to rtinit() where applicable and only use custom loops where
  currently not possible otherwise.
- Multicast group, most neighbor discovery address actions and faith(4)
  are locked to the default FIB.  Individual IPv6 addresses will only
  appear in the default FIB, however redirect information and prefixes
  of connected subnets are automatically propagated to all FIBs by
  default (mimicking IPv4 behavior as closely as possible).

Sponsored by:	Cisco Systems, Inc.
2012-02-03 13:08:44 +00:00
Rick Macklem
87b633678b When a "mount -u" switches an NFS mount point from TCP to UDP,
any thread doing an I/O RPC with a transfer size greater than
NFS_UDPMAXDATA will be hung indefinitely, retrying the RPC.
After a discussion on freebsd-fs@, I decided to add a warning
message for this case, as suggested by Jeremy Chadwick.

Suggested by:	freebsd at jdc.parodius.com (Jeremy Chadwick)
MFC after:	2 weeks
2012-01-31 03:58:26 +00:00
Rick Macklem
7f763fc39c A problem with respect to data read through the buffer cache for both
NFS clients was reported to freebsd-fs@ under the subject "NFS
corruption in recent HEAD" on Nov. 26, 2011. This problem occurred when
a TCP mounted root fs was changed to using UDP. I believe that this
problem was caused by the change in mnt_stat.f_iosize that occurred
because rsize was decreased to the maximum supported by UDP. This
patch fixes the problem by using v_bufobj.bo_bsize instead of f_iosize,
since the latter is set to f_iosize when the vnode is allocated, but
does not change for a given vnode when f_iosize changes.

Reported by:	pjd
Reviewed by:	kib
MFC after:	2 weeks
2012-01-27 02:46:12 +00:00
Rick Macklem
0149d177fb Revert r230516, since it doesn't really fix the problem. 2012-01-26 00:07:34 +00:00
Konstantin Belousov
d5210589b7 Fix remaining calls to cache_enter() in both NFS clients to provide
appropriate timestamps.  Restore the assertions which verify that
NCF_TS is set when timestamp is asked for.

Reviewed by:  jhb (previous version)
MFC after:    2 weeks
2012-01-25 20:48:20 +00:00
John Baldwin
0b17c7bea5 Add a timeout on positive name cache entries in the NFS client. That is,
we will only trust a positive name cache entry for a specified amount of
time before falling back to a LOOKUP RPC, even if the ctime for the file
handle matches the cached copy in the name cache entry.  The timeout is
configured via a new 'nametimeo' mount option and defaults to 60 seconds.
It may be set to zero to disable positive name caching entirely.

Reviewed by:	rmacklem
MFC after:	1 week
2012-01-25 20:05:58 +00:00
Rick Macklem
6403723880 If a mount -u is done to either NFS client that switches it
from TCP to UDP and the rsize/wsize/readdirsize is greater
than NFS_MAXDGRAMDATA, it is possible for a thread doing an
I/O RPC to get stuck repeatedly doing retries. This happens
because the RPC will use a resize/wsize/readdirsize that won't
work for UDP and, as such, it will keep failing indefinitely.
This patch returns an error for this case, to avoid the problem.
A discussion on freebsd-fs@ seemed to indicate that returning
an error was preferable to silently ignoring the "udp"/"mntudp"
option.
This problem was discovered while investigating a problem reported
by pjd@ via email.

MFC after:	2 weeks
2012-01-25 00:22:53 +00:00
John Baldwin
5aefb4cbbf Close a race in NFS lookup processing that could result in stale name cache
entries on one client when a directory was renamed on another client.  The
root cause for the stale entry being trusted is that each per-vnode nfsnode
structure has a single 'n_ctime' timestamp used to validate positive name
cache entries.  However, if there are multiple entries for a single vnode,
they all share a single timestamp.  To fix this, extend the name cache
to allow filesystems to optionally store a timestamp value in each name
cache entry.  The NFS clients now fetch the timestamp associated with
each name cache entry and use that to validate cache hits instead of the
timestamps previously stored in the nfsnode.  Another part of the fix is
that the NFS clients now use timestamps from the post-op attributes of
RPCs when adding name cache entries rather than pulling the timestamps out
of the file's attribute cache.  The latter is subject to races with other
lookups updating the attribute cache concurrently.  Some more details:
- Add a variant of nfsm_postop_attr() to the old NFS client that can return
  a vattr structure with a copy of the post-op attributes.
- Handle lookups of "." as a special case in the NFS clients since the name
  cache does not store name cache entries for ".", so we cannot get a
  useful timestamp.  It didn't really make much sense to recheck the
  attributes on the the directory to validate the namecache hit for "."
  anyway.
- ABI compat shims for the name cache routines are present in this commit
  so that it is safe to MFC.

MFC after:	2 weeks
2012-01-20 20:02:01 +00:00
Kirk McKusick
cc672d3599 Make sure all intermediate variables holding mount flags (mnt_flag)
and that all internal kernel calls passing mount flags are declared
as uint64_t so that flags in the top 32-bits are not lost.

MFC after: 2 weeks
2012-01-17 01:08:01 +00:00