For a LayoutReturn when using the Flexible File Layout,
error reports may be provided in the request.
Sanity check the size of these error reports and
check that they exist before calling nfsrv_flexlayouterr().
Reported by: rtm@lcs.mit.edu
Tested by: rtm@lcs.mit.edu
PR: 260012
MFC after: 2 weeks
For pNFS, Layouts are issued by the server to indicate
where a file's data resides on the DS(s). This patch
adds counters for how many layouts are allocated to
the nfsstatsv1 structure, using two reserved fields.
MFC after: 2 weeks
If a pNFS server's DS runs out of disk space, it replies
NFSERR_NOSPC to the client doing writing. For the Linux
client, it then sends a LayoutError RPC to the MDS server to
tell it about the error and keeps retrying, doing repeated
LayoutGets to the MDS and Write RPCs to the DS. The Linux client is
"stuck" until disk space on the DS is free'd up unless
a subsequent LayoutGet request is sent a NFSERR_NOSPC
reply.
The looping problem still occurs for NFSv4.1 mounts, but no
fix for this is known at this time.
This patch changes the pNFS MDS server to reply to LayoutGet
operations with NFSERR_NOSPC once a LayoutError reports the
problem, until the DS has available space. This keeps the Linux
NFSv4.2 from looping.
Found during recent testing because of issues w.r.t. a DS
being out of space found during a recent IEFT NFSv4 working
group testing event.
MFC after: 2 weeks
If a pNFS server's DS runs out of disk space, it replies
NFSERR_NOSPC to the client doing writing. For the Linux
client, it then sends a LayoutError RPC to the server to
tell it about the error and keeps retrying, doing repeated
LayoutGet and Write RPCs to the DS. The Linux client is
"stuck" until disk space on the DS is free'd up.
For a mirrored server configuration, the first mirror that
ran out of space was taken offline. This does not make
much sense, since the other mirror(s) will run out of space
soon and the fix is a manual cleanup up disk space.
This patch changes the pNFS server to not disable a mirror
for the mirrored case when this occurs.
Further work is needed, since the Linux client expects the
MDS to reply NFSERR_NOSPC to LayoutGets once the DS is out
of space. Without this further change, the above mentioned
looping occurs.
Found during a recent IEFT NFSv4 working group testing event.
MFC after: 2 weeks
Since MAXPHYS now allows the FreeBSD NFS client
to do 1Mbyte I/O operations, add a sysctl called vfs.nfsd.srvmaxio
so that the maximum NFS server I/O size can be set up to 1Mbyte.
The Linux NFS client can also do 1Mbyte I/O operations.
The default of 128Kbytes for the maximum I/O size has
not been changed for two reasons:
- kern.ipc.maxsockbuf must be increased to support 1Mbyte I/O
- The limited benchmarking I can do actually shows a drop in I/O rate
when the I/O size is above 256Kbytes.
However, daveb@spectralogic.com reports seeing an increase
in I/O rate for the 1Mbyte I/O size vs 128Kbytes using a Linux client.
Reviewed by: asomers
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D30826
Linux has had an "nconnect" NFS mount option for some time.
It specifies that N (up to 16) TCP connections are to created for a mount,
instead of just one TCP connection.
A discussion on freebsd-net@ indicated that this could improve
client<-->server network bandwidth, if either the client or server
have one of the following:
- multiple network ports aggregated to-gether with lagg/lacp.
- a fast NIC that is using multiple queues
It does result in using more IP port#s and might increase server
peak load for a client.
One difference from the Linux implementation is that this implementation
uses the first TCP connection for all RPCs composed of small messages
and uses the additional TCP connections for RPCs that normally have
large messages (Read/Readdir/Write). The Linux implementation spreads
all RPCs across all TCP connections in a round robin fashion, whereas
this implementation spreads Read/Readdir/Write across the additional
TCP connections in a round robin fashion.
Reviewed by: markj
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D30970
Michael Dexter <editor@callfortesting.org> reported
a crash in FreeNAS, where the first argument to
clnt_bck_svccall() was no longer valid.
This argument is a pointer to the callback CLIENT
structure, which is free'd when the associated
NFSv4 ClientID is free'd.
This appears to have occurred because a callback
reply was still in the socket receive queue when
the CLIENT structure was free'd.
This patch acquires a reference count on the CLIENT
that is not CLNT_RELEASE()'d until the socket structure
is destroyed. This should guarantee that the CLIENT
structure is still valid when clnt_bck_svccall() is called.
It also adds a check for closed or closing to
clnt_bck_svccall() so that it will not process the callback
RPC reply message after the ClientID is free'd.
Comments by: mav
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D30153
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
Commit 4281bfec36 patched the server so that the
callback session slot would be free'd for reuse when
a callback attempt fails.
However, this can often result in the sequence# for
the session slot to be advanced such that the client
end will reply NFSERR_SEQMISORDERED.
To avoid the NFSERR_SEQMISORDERED client reply,
this patch negates the sequence# advance for the
case where the callback has failed.
The common case is a failed back channel, where
the callback cannot be sent to the client, and
not advancing the sequence# is correct for this
case. For the uncommon case where the client's
reply to the callback is lost, not advancing the
sequence# will indicate to the client that the
next callback is a retry and not a new callback.
But, since the FreeBSD server always sets "csa_cachethis"
false in the callback sequence operation, a retry
and a new callback should be handled the same way
by the client, so this should not matter.
Until you have this patch in your NFSv4.1/4.2 server,
you should consider avoiding the use of delegations.
Even with this patch, interoperation with the
Linux NFSv4.1/4.2 client in kernel versions prior
to 5.3 can result in frequent 15second delays if
delegations are enabled. This occurs because, for
kernels prior to 5.3, the Linux client does a TCP
reconnect every time it sees multiple concurrent
callbacks and then it takes 15seconds to recover
the back channel after doing so.
MFC after: 2 weeks
When the NFSv4.1/4.2 server does a callback to a client
on the back channel, it will use a session slot in the
back channel session. If the back channel has failed,
the callback will fail and, without this patch, the
session slot will not be released.
As more callbacks are attempted, all session slots
can become busy and then the nfsd thread gets stuck
waiting for a back channel session slot.
This patch frees the session slot upon callback
failure to avoid this problem.
Without this patch, the problem can be avoided by leaving
delegations disabled in the NFS server.
MFC after: 2 weeks
At a recent testing event I found out that I had misinterpreted
RFC5661 where it describes the stripe size in the File Layout's
nfl_util field. This patch fixes the pNFS File Layout server
so that it returns the correct value to the NFSv4.1/4.2 pNFS
enabled client.
This affects almost no one, since pNFS server configurations
are rare and the extant pNFS aware NFS clients seemed to
function correctly despite the erroneous stripe size.
It *might* be needed for correct behaviour if a recent
Linux client mounts a FreeBSD pNFS server configuration
that is using File Layout (non-mirrored configuration).
MFC after: 2 weeks
Commit 01ae8969a9 stopped the NFSv4.1/4.2 server from implicitly
binding the back channel to a new TCP connection so that it
conforms to RFC5661, for NFSv4.1/4.2. An effect of this
for the Linux NFS client is that it will do a
BindConnectionToSession when it sees NFSV4SEQ_CBPATHDOWN
set in a sequence reply. This will fix the back channel, but the
first attempt at a callback like CB_RECALL will already have
failed. Without this patch, a CB_RECALL will not be retried
and that can result in a 5 minute delay until the delegation
times out.
This patch modifies the code so that it will retry the
CB_RECALL every couple of seconds, often avoiding the
5 minute delay.
This is not critical for correct behaviour, but avoids
the 5 minute delay for the case where the Linux client
re-binds the back channel via BindConnectionToSession.
MFC after: 2 weeks
Commit 01ae8969a9 stopped the NFSv4.1/4.2 server from implicitly
binding the back channel to a new TCP connection so that it
conforms to RFC5661, for NFSv4.1/4.2. An effect of this
for the Linux NFS client is that it will do a
BindConnectionToSession when it sees NFSV4SEQ_CBPATHDOWN
set in a sequence reply. It will do this for every RPC
reply until it no longer sees the flag.
Without that patch, this will happen until the client does
an Open, which will clear LCL_CBDOWN.
This patch clears LCL_CBDOWN right away, so that
NFSV4SEQ_CBPATHDOWN will no longer be sent to the client
in Sequence replies and the Linux client will not repeat
the BindConnectionToSession RPCs.
This is not critical for correct behaviour, but reduces
RPC overheads for cases where the Open will not be done
for a while.
MFC after: 2 weeks
The NFSv4.1 (and 4.2 on 13) server incorrectly binds
a new TCP connection to the back channel when first
used by an RPC with a Sequence op in it (almost all of them).
RFC5661 specifies that only the fore channel should be bound.
This was done because early clients (including FreeBSD)
did not do the required BindConnectionToSession RPC.
Unfortunately, this breaks the Linux client when the
"nconnects" mount option is used, since the server
may do a callback on the incorrect TCP connection.
This patch converts the server behaviour to that
required by the RFC. It also makes the server test/indicate
failure of the back channel more aggressively.
Until this patch is applied to the server, the
"nconnects" mount option is not recommended for a Linux
NFSv4.1/4.2 client mount to the FreeBSD server.
Reported by: bcodding@redhat.com
Tested by: bcodding@redhat.com
PR: 254560
MFC after: 1 week
Commit 774a36851e fixed the NFS server so that it could handle
ERELOOKUP returns from VOP calls by redoing the operation/RPC.
However, for NFSv4.0, redoing an Open would increment
the open_owner's seqid multiple times, breaking the protocol.
This patch sets a new flag called ND_ERELOOKUP on the RPC when
a redo is in progress. Then the code that increments the seqid
avoids the seqid increment/check when the flag is set, since
it indicates this has already been done for the Open.
using an open_to_lock_owner4 when that lock_owner4 has already
been created by a previous open_to_lock_owner4. This caused the NFS server
to reply NFSERR_INVAL.
For NFSv4.0, this is an error, although the updated NFSv4.0 RFC7530 notes
that the correct error reply is NFSERR_BADSEQID (RFC3530 did not specify
what error to return).
For NFSv4.1, it is not obvious whether or not this is allowed by RFC5661,
but the NFSv4.1 server can handle this case without error.
This patch changes the NFSv4.1 (and NFSv4.2) server to handle multiple
uses of the same lock_owner in open_to_lock_owner so that it now correctly
interoperates with the Linux NFS client.
It also changes the error returned for NFSv4.0 to be NFSERR_BADSEQID.
Thanks go to Bjorn for diagnosing this and testing the patch.
He also provided a program that I could use to reproduce the problem.
Tested by: bj@cebitec.uni-bielefeld.de (Bjorn Fischer)
PR: 249567
Reported by: bj@cebitec.uni-bielefeld.de (Bjorn Fischer)
MFC after: 3 days
Recent testing of the NFS-over-TLS code found a LOR between the mutex lock
used for sessions and the sleep lock used for server side krpc socket
structures in nfsrv_checksequence(). This was fixed by r365789.
A similar bug exists in nfsrv_bindconnsess(), where SVC_RELEASE() is called
while mutexes are held.
This patch applies a fix similar to r365789, moving the SVC_RELEASE() call
down to after the mutexes are released.
This patch fixes the problem by moving the SVC_RELEASE() call in
nfsrv_checksequence() down a few lines to below where the mutex is released.
MFC after: 1 week
Recent testing of the NFS-over-TLS code found a LOR between the mutex lock
used for sessions and the sleep lock used for server side krpc socket
structures.
The code in nfsrv_checksequence() would call SVC_RELEASE() with the mutex
held. Normally this is ok, since all that happens is SVC_RELEASE()
decrements a reference count. However, if the socket has just been shut
down, SVC_RELEASE() drops the reference count to 0 and acquires a sleep
lock during destruction of the server side krpc structure.
This patch fixes the problem by moving the SVC_RELEASE() call in
nfsrv_checksequence() down a few lines to below where the mutex is released.
MFC after: 1 week
asomers@ reported a crash on an NFSv4.0 server with a backtrace of:
kdb_backtrace
vpanic
panic
nfsrv_docallback
nfsrv_checkgetattr
nfsrvd_getattr
nfsrvd_dorpc
nfssvc_program
svc_run_internal
svc_thread_start
fork_exit
fork_trampoline
where the panic message was "docallb", which indicates that a callback
was attempted when the ClientID is unconfirmed.
This would not normally occur, but it is possible to have an unconfirmed
ClientID structure with delegation structure(s) chained off it if the
client were to issue a SetClientID with the same "id" but different
"verifier" after acquiring delegations on the previously confirmed ClientID.
The bug appears to be that nfsrv_checkgetattr() failed to check for
this uncommon case of an unconfirmed ClientID with a delegation structure
that no longer refers to a delegation the client knows about.
This patch adds a check for this case, handling it as if no delegation
exists, which is the case when the above occurs.
Although difficult to reproduce, this change should avoid the panic().
PR: 249127
Reported by: asomers
Reviewed by: asomers
MFC after: 1 week
Differential Revision: https://reviews.freebbsd.org/D26342
For NFSv4.0, the server creates a server->client TCP connection for callbacks.
If the client mount on the server is using TLS, enable TLS for this callback
TCP connection.
TLS connections from clients will not be supported until the kernel RPC
changes are committed.
Since this changes the internal ABI between the NFS kernel modules that
will require a version bump, delete newnfs_trimtrailing(), which is no
longer used.
Since LCL_TLSCB is not yet set, these changes should not have any semantic
affect at this time.
Comparing fsid_t objects requires internal knowledge of the fsid structure
and yet this is duplicated across a number of places in the code.
Simplify by creating a fsidcmp function (macro).
Reviewed by: mjg, rmacklem
Approved by: mav (mentor)
MFC after: 1 week
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D24749
The typedef mbuf_t was used for the Mac OS/X port of the code long ago.
Since this port is no longer used and the use of mbuf_t obscures what
the code does (and is not consistent with style(9)), it is no longer needed.
This patch replaces all instances of mbuf_t with "struct mbuf *", so that
it is no longer used.
This patch should not result in any semantic change.
When the code was ported to Mac OS/X, mbuf handling functions were
converted to using the Mac OS/X accessor functions. For FreeBSD, they
are a simple set of macros in sys/fs/nfs/nfskpiport.h.
Since porting to Mac OS/X is no longer a consideration, replacement of
these macros with the code generated by them makes the code more
readable.
When support for external page mbufs is added as needed by the KERN_TLS,
the patch becomes simpler if done without the macros.
This patch should not result in any semantic change.
Peter reported that his dmesg was getting cluttered with
nfsrv_cache_session: no session
messages when he rebooted his NFS server and they did not seem useful.
He was correct, in that these messages are "normal" and expected when
NFSv4.1 or NFSv4.2 are mounted and the server is rebooted.
This patch silences the printf() during the grace period after a reboot.
It also adds the client IP address to the printf(), so that the message
is more useful if/when it occurs. If this happens outside of the
server's grace period, it does indicate something is not working correctly.
Instead of adding yet another nd_XXX argument, the arguments for
nfsrv_cache_session() were simplified to take a "struct nfsrv_descript *".
Reported by: pen@lysator.liu.se
MFC after: 2 weeks
The PR reported a crash that occurred when a file was removed while
client(s) were actively doing lock operations on it.
Since nfsvno_getvp() will return NULL when the file does not exist,
the bug was obvious and easy to fix via this patch. It is a little
surprising that this wasn't found sooner, but I guess the above
case rarely occurs.
Tested by: iron.udjin@gmail.com
PR: 242768
Reported by: iron.udjin@gmail.com
MFC after: 2 weeks
Filesystems which want to use it in limited capacity can employ the
VOP_UNLOCK_FLAGS macro.
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D21427
None of these case were actually using the variable(s) uninitialized, but
I figured that silencing the warnings via initializing them made sense.
Some of these predated r355677.
This patch adds support for NFSv4.2 (RFC-7862) and Extended Attributes
(RFC-8276) to the NFS client and server.
NFSv4.2 is comprised of several optional features that can be supported
in addition to NFSv4.1. This patch adds the following optional features:
- posix_fadvise(POSIX_FADV_WILLNEED/POSIX_FADV_DONTNEED)
- posix_fallocate()
- intra server file range copying via the copy_file_range(2) syscall
--> Avoiding data tranfer over the wire to/from the NFS client.
- lseek(SEEK_DATA/SEEK_HOLE)
- Extended attribute syscalls for "user" namespace attributes as defined
by RFC-8276.
Although this patch is fairly large, it should not affect support for
the other versions of NFS. However it does add two new sysctls that allow
a sysadmin to limit which minor versions of NFSv4 a server supports, allowing
a sysadmin to disable NFSv4.2.
Unfortunately, when the NFS stats structure was last revised, it was assumed
that there would be no additional operations added beyond what was
specified in RFC-7862. However RFC-8276 did add additional operations,
forcing the NFS stats structure to revised again. It now has extra unused
entries in all arrays, so that future extensions to NFSv4.2 can be
accomodated without revising this structure again.
A future commit will update nfsstat(1) to report counts for the new NFSv4.2
specific operations/procedures.
This patch affects the internal interface between the nfscommon, nfscl and
nfsd modules and, as such, they all must be upgraded simultaneously.
I will do a version bump (although arguably not needed), due to this.
This code has survived a "make universe" but has not been built with a
recent GCC. If you encounter build problems, please email me.
Relnotes: yes
The current vnode layout is not smp-friendly by having frequently read data
avoidably sharing cachelines with very frequently modified fields. In
particular v_iflag inspected for VI_DOOMED can be found in the same line with
v_usecount. Instead make it available in the same cacheline as the v_op, v_data
and v_type which all get read all the time.
v_type is avoidably 4 bytes while the necessary data will easily fit in 1.
Shrinking it frees up 3 bytes, 2 of which get used here to introduce a new
flag field with a new value: VIRF_DOOMED.
Reviewed by: kib, jeff
Differential Revision: https://reviews.freebsd.org/D22715
The "nd" argument for nfsrv_checkdsattr() is no longer used by the function.
This patch deletes it. This allows subsequent patches to delete the "nd"
argument from nfsrv_proxyds(), since it's only use of "nd" was to pass it
to nfsrv_checkdsattr(). The same will then be true for nfsvno_getattr(),
which passes "nd" to nfsrv_proxyds().
Getting rid of the "nd" argument from nfsvno_getattr() avoids confusion
over why it might need "nd".
This patch is trivial and does not have any semantic effect.
Found by inspection while working on the NFSv4.2 server.
PR#223036 reported that INET6 callback addresses were not printed by
nfsdumpstate(8). This kernel patch adds INET6 addresses to the dump structure,
so that nfsdumpstate(8) can print them out, post-r346190.
The patch also includes the addition of #ifdef INET, INET6 as requested
by bz@.
PR: 223036
Reviewed by: bz, rgrimes
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D19839
When coding the pNFS server, I added vn_start_write() calls in nfsrv_copymr()
done while the vnodes were locked, not realizing I had introduced LORs and
possible deadlock when an exported file system on the MDS is suspended.
This patch fixes the LORs by moving the vn_start_write() calls up to before
where the vnodes are locked. For "tvp", the vn_start_write() probaby isn't
necessary, because NFS mounts can't be suspended. However, I think doing
so is harmless.
Thanks go to kib@ for letting me know that I had introduced these LORs.
This patch only affects the behaviour of the pNFS server when pnfsdscopymr(8)
is used to recover a mirrored DS.
After a re-read of the appropriate section of RFC5661, I decided that a
few things should be changed related to LayoutRecall callback handling.
Here are the things fixed by this patch.
- For two of the three cases that LayoutRecall is done, I now think
setting the clora_changed argument false is correct.
- All errors other than NFSERR_DELAY returned by LayoutRecall appear
permanent, so don't retry for any of them. (NFSERR_DELAY is retried by
newnfs_request(), so it is not affected by this patch.)
- Instead of waiting "forever" (actually until the process is SIGTERM'd)
for Layouts to be returned during a mirror copy, fail and return
ENXIO after about 1minute.
Waiting for a <ctrl>C made sense when pnfsdscopymr() was done by itself,
but did not make sense when done via find(1).
This patch only affects the pNFS server.
At least on x86, fhandle_t is a packed structure, so I believe an
assignment will copy all the bits. However, for some current/future
architectures, there might be padding in the structure that doesn't get
copied via an assignment.
Since NFS assumes a file handle is an opaque blob of bits that can be
compared via memcmp()/bcmp(), all the bits including any padding must be
copied.
This patch replaces the assignments with a call to a byte copy function.
Spotted during code inspection.
I believe that a ReclaimComplete with rca_one_fs == TRUE is only
to be used after a file system has been transferred to a different
file server. However, RFC5661 is somewhat vague w.r.t. this and
the ESXi 6.7 client does both a ReclaimComplete with rca_one_fs == TRUE
and one with ReclaimComplete with rca_one_fs == FALSE.
Therefore, just ignore the rca_one_fs == TRUE operation and return
NFS_OK without doing anything instead of replying NFS4ERR_NOTSUPP.
This allows the ESXi 6.7 NFSv4.1 client to do a mount.
After discussion on the NFSv4 IETF working group mailing list, doing this
along with setting a flag to note that a ReclaimComplete with rca_one_fs TRUE
was an appropriate way to handle this.
The flag that indicates that a ReclaimComplete with rca_one_fs == TRUE was
done may be used to disable replies of NFS4ERR_GRACE for non-reclaim
state operations in a future commit.
This patch along with r332790, r334492 and r336357 allow ESXi 6.7 NFSv4.1 mounts
work ok. ESX 6.5 NFSv4.1 mounts do not work well, due to what I believe are
violations of RFC-5661 and should not be used.
Reported by: andreas.nagy@frequentis.com
Tested by: andreas.nagy@frequentis.com, daniel@ftml.net (earlier version)
MFC after: 2 weeks
Relnotes: yes
The ESXi NFSv4.1 client will generate warning messages when the reason for
not issuing a delegation is two. Two refers to a resource limit and I do
not see why it would be considered invalid. However it probably was not the
best choice of reason for not issuing a delegation.
This patch changes the reasons used to ones that the ESXi client doesn't
complain about. This change does not affect the FreeBSD client and does
not appear to affect behaviour of the Linux NFSv4.1 client.
RFC5661 defines these "reasons" but does not give any guidance w.r.t. which
ones are more appropriate to return to a client.
Tested by: andreas.nagy@frequentis.com
PR: 226650
MFC after: 2 weeks
The pnfsdskill(8) command will normally fail if there is no valid mirror
for the DS to be disabled. However, a system administrator may need to
disable a DS which does not have a valid mirror so that the nfsd threads
can be terminated. This patch adds the kernel code needed by pnfsdskill(8)
to implement this "forced" case of disabling a DS.
This patch only affects the pNFS server.
If a mirrored DS is being recovered that has a lot of large sparse files,
pnfsdscopymr(8) would use a lot of space on the recovered mirror since it
would write the "holes" in the file being mirrored.
This patch adds code to check for a "hole" and skip doing the write.
The check is done on a "per PNFSDS_COPYSIZ size block", which is currently 64K.
I think that most file server file systems will be using a blocksize at
least this large. If the file server is using a smaller blocksize and
smaller holes need to be preserved, PNFSDS_COPYSIZ could be decreased.
The block of 0s is malloc()d, since pnfsdcopymr(8) should be an infrequent
occurrence.
an NFSERR_STALE error reported via a LayoutReturn.
The current FreeBSD client can generate these errors for an operational
DS while doing a recovery of a mirror after a mirrored DS has been repaired.
I am not sure why these errors occur, but my best current guess is a race
between the Layout Recall issued by the kernel code run from pnfsdscopymr(8)
and a Read operation on the DS for the file bing copied.
The errors are not fatal, since the client falls back on doing I/O through
the MDS, which can do the I/O successfully as a proxy. (The fact that the
MDS can do this indicates that the file does still exist on the functioning
DS.)
This change only affects the pNFS server and only when a client does a
LayoutReturn with the NFSERR_STALE error report.
The recently added feature of the pNFS server will set an fsid for the
MDS file system to define the file system a DS should store files for.
For a case where a DS handling all file systems has failed, it was possible
for the code to check for a mirror with a specified fs, even though
nfsdev_mdsisset was 0, possibly causing a false successful check for a mirror.
This patch adds a check for nfsdev_mdsisset != 0 to avoid this.
It only affects the pNFS server for a rare case. Found via code inspection.
Without this patch, the pNFS server distributes the data storage files across
all of the specified DSs.
A tester noted that it would be nice if a system administrator could control
which DSs are used to store the file data for a given exported MDS file system.
This patch adds the kernel support to do this. It also makes a slight semantic
change to nfsv4_findmirror(), since some uses of it no longer require that
the DS being searched for have a current mirror.
A patch that will be committed in a few minutes will modify the nfsd daemon
to support this feature.
The patch should only affect sites using the pNFS server (specified via the
"-p" command line option for nfsd.
Suggested by: james.rose@framestore.com
This patch adds a counter that limits the number of disabled mirrored DSs
to mirror level - 1. It also makes a small change that keeps a Write that
has failed with EACCES when attempted by a client to a DS from disabling
the DS.
This patch only affects the pNFS server.
This code merge adds a pNFS service to the NFSv4.1 server. Although it is
a large commit it should not affect behaviour for a non-pNFS NFS server.
Some documentation on how this works can be found at:
http://people.freebsd.org/~rmacklem/pnfs-planb-setup.txt
and will hopefully be turned into a proper document soon.
This is a merge of the kernel code. Userland and man page changes will
come soon, once the dust settles on this merge.
It has passed a "make universe", so I hope it will not cause build problems.
It also adds NFSv4.1 server support for the "current stateid".
Here is a brief overview of the pNFS service:
A pNFS service separates the Read/Write oeprations from all the other NFSv4.1
Metadata operations. It is hoped that this separation allows a pNFS service
to be configured that exceeds the limits of a single NFS server for either
storage capacity and/or I/O bandwidth.
It is possible to configure mirroring within the data servers (DSs) so that
the data storage file for an MDS file will be mirrored on two or more of
the DSs.
When this is used, failure of a DS will not stop the pNFS service and a
failed DS can be recovered once repaired while the pNFS service continues
to operate. Although two way mirroring would be the norm, it is possible
to set a mirroring level of up to four or the number of DSs, whichever is
less.
The Metadata server will always be a single point of failure,
just as a single NFS server is.
A Plan B pNFS service consists of a single MetaData Server (MDS) and K
Data Servers (DS), all of which are recent FreeBSD systems.
Clients will mount the MDS as they would a single NFS server.
When files are created, the MDS creates a file tree identical to what a
single NFS server creates, except that all the regular (VREG) files will
be empty. As such, if you look at the exported tree on the MDS directly
on the MDS server (not via an NFS mount), the files will all be of size 0.
Each of these files will also have two extended attributes in the system
attribute name space:
pnfsd.dsfile - This extended attrbute stores the information that
the MDS needs to find the data storage file(s) on DS(s) for this file.
pnfsd.dsattr - This extended attribute stores the Size, AccessTime, ModifyTime
and Change attributes for the file, so that the MDS doesn't need to
acquire the attributes from the DS for every Getattr operation.
For each regular (VREG) file, the MDS creates a data storage file on one
(or more if mirroring is enabled) of the DSs in one of the "dsNN"
subdirectories. The name of this file is the file handle
of the file on the MDS in hexadecimal so that the name is unique.
The DSs use subdirectories named "ds0" to "dsN" so that no one directory
gets too large. The value of "N" is set via the sysctl vfs.nfsd.dsdirsize
on the MDS, with the default being 20.
For production servers that will store a lot of files, this value should
probably be much larger.
It can be increased when the "nfsd" daemon is not running on the MDS,
once the "dsK" directories are created.
For pNFS aware NFSv4.1 clients, the FreeBSD server will return two pieces
of information to the client that allows it to do I/O directly to the DS.
DeviceInfo - This is relatively static information that defines what a DS
is. The critical bits of information returned by the FreeBSD
server is the IP address of the DS and, for the Flexible
File layout, that NFSv4.1 is to be used and that it is
"tightly coupled".
There is a "deviceid" which identifies the DeviceInfo.
Layout - This is per file and can be recalled by the server when it
is no longer valid. For the FreeBSD server, there is support
for two types of layout, call File and Flexible File layout.
Both allow the client to do I/O on the DS via NFSv4.1 I/O
operations. The Flexible File layout is a more recent variant
that allows specification of mirrors, where the client is
expected to do writes to all mirrors to maintain them in a
consistent state. The Flexible File layout also allows the
client to report I/O errors for a DS back to the MDS.
The Flexible File layout supports two variants referred to as
"tightly coupled" vs "loosely coupled". The FreeBSD server always
uses the "tightly coupled" variant where the client uses the
same credentials to do I/O on the DS as it would on the MDS.
For the "loosely coupled" variant, the layout specifies a
synthetic user/group that the client uses to do I/O on the DS.
The FreeBSD server does not do striping and always returns
layouts for the entire file. The critical information in a layout
is Read vs Read/Writea and DeviceID(s) that identify which
DS(s) the data is stored on.
At this time, the MDS generates File Layout layouts to NFSv4.1 clients
that know how to do pNFS for the non-mirrored DS case unless the sysctl
vfs.nfsd.default_flexfile is set non-zero, in which case Flexible File
layouts are generated.
The mirrored DS configuration always generates Flexible File layouts.
For NFS clients that do not support NFSv4.1 pNFS, all I/O operations
are done against the MDS which acts as a proxy for the appropriate DS(s).
When the MDS receives an I/O RPC, it will do the RPC on the DS as a proxy.
If the DS is on the same machine, the MDS/DS will do the RPC on the DS as
a proxy and so on, until the machine runs out of some resource, such as
session slots or mbufs.
As such, DSs must be separate systems from the MDS.
Tested by: james.rose@framestore.com
Relnotes: yes
Under some fairly unusual circumstances, the Linux NFSv4.1 client is
doing a BindConnectiontoSession operation for TCP connections.
It is also used by the ESXi6.5 NFSv4.1 client.
This patch adds this operation to the NFSv4.1 server.
Reported by: andreas.nagy@frequentis.com
Tested by: andreas.nagy@frequentis.com
MFC after: 2 weeks
If a client did a DestroySession on a session while it was still in use,
the server might try to use the session structure after it is free'd.
I think the client has violated RFC5661 if it does this, but this patch
makes DestroySession block all other nfsd threads so no thread could
be using the session when it is free'd. After the DestroySession, nfsd
threads will not be able to find the session. The patch also adds a check
for nd_sessionid being set, although if that was not the case it would have
been all 0s and unlikely to have a false match.
This might fix the crashes described in PR#228497 for the FreeNAS server.
PR: 228497
MFC after: 1 week
