Commit Graph

841 Commits

Author SHA1 Message Date
Jeff Layton
91885258e8 nfsd: don't break lease while servicing a COMMIT
This is the second attempt to fix the problem whereby a COMMIT call
causes a lease break and triggers a possible deadlock.

The problem is that nfsd attempts to break a lease on a COMMIT call.
This triggers a delegation recall if the lease is held for a delegation.
If the client is the one holding the delegation and it's the same one on
which it's issuing the COMMIT, then it can't return that delegation
until the COMMIT is complete. But, nfsd won't complete the COMMIT until
the delegation is returned. The client and server are essentially
deadlocked until the state is marked bad (due to the client not
responding on the callback channel).

The first patch attempted to deal with this by eliminating the open of
the file altogether and simply had nfsd_commit pass a NULL file pointer
to the vfs_fsync_range. That would conflict with some work in progress
by Christoph Hellwig to clean up the fsync interface, so this patch
takes a different approach.

This declares a new NFSD_MAY_NOT_BREAK_LEASE access flag that indicates
to nfsd_open that it should not break any leases when opening the file,
and has nfsd_commit set that flag on the nfsd_open call.

For now, this patch leaves nfsd_commit opening the file with write
access since I'm not clear on what sort of access would be more
appropriate.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-03-22 15:37:53 -04:00
NeilBrown
61f8603d93 nfsd: factor out hash functions for export caches.
Both the _lookup and the _update functions for these two caches
independently calculate the hash of the key.
So factor out that code for improved reuse.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-03-16 18:05:11 -04:00
J. Bruce Fields
e739cf1da4 Merge commit 'v2.6.34-rc1' into for-2.6.35-incoming 2010-03-09 17:22:08 -05:00
J. Bruce Fields
e7b184f199 nfsd4: document lease/grace-period limits
The current documentation here is out of date, and not quite right.

(Future work: some user documentation would be useful.)

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-03-06 15:02:10 -05:00
J. Bruce Fields
efc4bb4fdd nfsd4: allow setting grace period time
Allow explicit configuration of the grace period time as well as the
lease period time.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-03-06 15:02:08 -05:00
J. Bruce Fields
f013574014 nfsd4: reshuffle lease-setting code to allow reuse
We'll soon allow setting the grace period, so we'll want to share this
code.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-03-06 15:02:03 -05:00
J. Bruce Fields
f958a1320f nfsd4: remove unnecessary lease-setting function
This is another layer of indirection that doesn't really buy us
anything.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-03-06 15:02:03 -05:00
J. Bruce Fields
e46b498c84 nfsd4: simplify lease/grace interaction
The original code here assumed we'd allow the user to change the lease
any time, but only allow the change to take effect on restart.  Since
then we modified the code to allow setting the lease on when the server
is down.  Update the rest of the code to reflect that fact, clarify
variable names, and add document.

Also, the code insisted that the grace period always be the longer of
the old and new lease periods, but that's overly conservative--as long
as it lasts at least the old lease period, old clients should still know
to recover in time.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-03-06 15:02:02 -05:00
J. Bruce Fields
cf07d2ea43 nfsd4: simplify references to nfsd4 lease time
Instead of accessing the lease time directly, some users call
nfs4_lease_time(), and some a macro, NFSD_LEASE_TIME, defined as
nfs4_lease_time().  Neither layer of indirection serves any purpose.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-03-06 15:02:01 -05:00
Linus Torvalds
05c5cb31ec Merge branch 'for-2.6.34' of git://linux-nfs.org/~bfields/linux
* 'for-2.6.34' of git://linux-nfs.org/~bfields/linux: (22 commits)
  nfsd4: fix minor memory leak
  svcrpc: treat uid's as unsigned
  nfsd: ensure sockets are closed on error
  Revert "sunrpc: move the close processing after do recvfrom method"
  Revert "sunrpc: fix peername failed on closed listener"
  sunrpc: remove unnecessary svc_xprt_put
  NFSD: NFSv4 callback client should use RPC_TASK_SOFTCONN
  xfs_export_operations.commit_metadata
  commit_metadata export operation replacing nfsd_sync_dir
  lockd: don't clear sm_monitored on nsm_reboot_lookup
  lockd: release reference to nsm_handle in nlm_host_rebooted
  nfsd: Use vfs_fsync_range() in nfsd_commit
  NFSD: Create PF_INET6 listener in write_ports
  SUNRPC: NFS kernel APIs shouldn't return ENOENT for "transport not found"
  SUNRPC: Bury "#ifdef IPV6" in svc_create_xprt()
  NFSD: Support AF_INET6 in svc_addsock() function
  SUNRPC: Use rpc_pton() in ip_map_parse()
  nfsd: 4.1 has an rfc number
  nfsd41: Create the recovery entry for the NFSv4.1 client
  nfsd: use vfs_fsync for non-directories
  ...
2010-03-06 11:31:38 -08:00
Wu Fengguang
42e4960868 vfs: take f_lock on modifying f_mode after open time
We'll introduce FMODE_RANDOM which will be runtime modified.  So protect
all runtime modification to f_mode with f_lock to avoid races.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: <stable@kernel.org>			[2.6.33.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 11:26:25 -08:00
Linus Torvalds
e213e26ab3 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs-2.6
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs-2.6: (33 commits)
  quota: stop using QUOTA_OK / NO_QUOTA
  dquot: cleanup dquot initialize routine
  dquot: move dquot initialization responsibility into the filesystem
  dquot: cleanup dquot drop routine
  dquot: move dquot drop responsibility into the filesystem
  dquot: cleanup dquot transfer routine
  dquot: move dquot transfer responsibility into the filesystem
  dquot: cleanup inode allocation / freeing routines
  dquot: cleanup space allocation / freeing routines
  ext3: add writepage sanity checks
  ext3: Truncate allocated blocks if direct IO write fails to update i_size
  quota: Properly invalidate caches even for filesystems with blocksize < pagesize
  quota: generalize quota transfer interface
  quota: sb_quota state flags cleanup
  jbd: Delay discarding buffers in journal_unmap_buffer
  ext3: quota_write cross block boundary behaviour
  quota: drop permission checks from xfs_fs_set_xstate/xfs_fs_set_xquota
  quota: split out compat_sys_quotactl support from quota.c
  quota: split out netlink notification support from quota.c
  quota: remove invalid optimization from quota_sync_all
  ...

Fixed trivial conflicts in fs/namei.c and fs/ufs/inode.c
2010-03-05 13:20:53 -08:00
Christoph Hellwig
907f4554e2 dquot: move dquot initialization responsibility into the filesystem
Currently various places in the VFS call vfs_dq_init directly.  This means
we tie the quota code into the VFS.  Get rid of that and make the
filesystem responsible for the initialization.   For most metadata operations
this is a straight forward move into the methods, but for truncate and
open it's a bit more complicated.

For truncate we currently only call vfs_dq_init for the sys_truncate case
because open already takes care of it for ftruncate and open(O_TRUNC) - the
new code causes an additional vfs_dq_init for those which is harmless.

For open the initialization is moved from do_filp_open into the open method,
which means it happens slightly earlier now, and only for regular files.
The latter is fine because we don't need to initialize it for operations
on special files, and we already do it as part of the namespace operations
for directories.

Add a dquot_file_open helper that filesystems that support generic quotas
can use to fill in ->open.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
2010-03-05 00:20:30 +01:00
J. Bruce Fields
4ea41e2de5 Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs into for-2.6.34-incoming
Resolve merge conflict in fs/xfs/linux-2.6/xfs_export.c.
2010-03-04 12:04:51 -05:00
J. Bruce Fields
8d75da8afd nfsd4: fix minor memory leak
There's no need to allocate this cred more than once.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-03-03 16:13:29 -05:00
Al Viro
462d60577a fix NFS4 handling of mountpoint stat
RFC says we need to follow the chain of mounts if there's more
than one stacked on that point.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-03-03 14:07:57 -05:00
Al Viro
8737c9305b Switch may_open() and break_lease() to passing O_...
... instead of mixing FMODE_ and O_

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-03-03 13:00:21 -05:00
Chuck Lever
58255a4e3c NFSD: NFSv4 callback client should use RPC_TASK_SOFTCONN
The server's callback client should stop trying to connect to the
client's callback server as soon as it gets ECONNREFUSED.

The NFS server's callback client does not call rpc_ping(), but appears
to have it's own "ping" procedure, so it wasn't covered by commit
caabea8a.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-02-24 17:50:28 -08:00
Ben Myers
f501912a35 commit_metadata export operation replacing nfsd_sync_dir
- Add commit_metadata export_operation to allow the underlying filesystem to
decide how to commit an inode most efficiently.

- Usage of nfsd_sync_dir and write_inode_now has been replaced with the
commit_metadata function that takes a svc_fh.

- The commit_metadata function calls the commit_metadata export_op if it's
there, or else falls back to sync_inode instead of fsync and write_inode_now
because only metadata need be synced here.

- nfsd4_sync_rec_dir now uses vfs_fsync so that commit_metadata can be static

Signed-off-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-02-20 13:13:44 -08:00
Chuck Ebbert
aeaa5ccd64 vfs: don't call ima_file_check() unconditionally in nfsd_open()
commit 1e41568d73 ("Take ima_path_check()
in nfsd past dentry_open() in nfsd_open()") moved this code back to its
original location but missed the "else".

Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-02-20 00:47:31 -05:00
Linus Torvalds
deb0c98c7f Merge branch 'for-2.6.33' of git://linux-nfs.org/~bfields/linux
* 'for-2.6.33' of git://linux-nfs.org/~bfields/linux:
  Revert "nfsd4: fix error return when pseudoroot missing"
2010-02-08 17:08:01 -08:00
J. Bruce Fields
260c64d235 Revert "nfsd4: fix error return when pseudoroot missing"
Commit f39bde24b2 fixed the error return from PUTROOTFH in the
case where there is no pseudofilesystem.

This is really a case we shouldn't hit on a correctly configured server:
in the absence of a root filehandle, there's no point accepting version
4 NFS rpc calls at all.

But the shared responsibility between kernel and userspace here means
the kernel on its own can't eliminate the possiblity of this happening.
And we have indeed gotten this wrong in distro's, so new client-side
mount code that attempts to negotiate v4 by default first has to work
around this case.

Therefore when commit f39bde24b2 arrived at roughly the same
time as the new v4-default mount code, which explicitly checked only for
the previous error, the result was previously fine mounts suddenly
failing.

We'll fix both sides for now: revert the error change, and make the
client-side mount workaround more robust.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-02-08 15:25:23 -05:00
Mimi Zohar
9bbb6cad01 ima: rename ima_path_check to ima_file_check
ima_path_check actually deals with files!  call it ima_file_check instead.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-02-07 03:06:22 -05:00
Mimi Zohar
8eb988c70e fix ima breakage
The "Untangling ima mess, part 2 with counters" patch messed
up the counters.  Based on conversations with Al Viro, this patch
streamlines ima_path_check() by removing the counter maintaince.
The counters are now updated independently, from measuring the file,
in __dentry_open() and alloc_file() by calling ima_counts_get().
ima_path_check() is called from nfsd and do_filp_open().
It also did not measure all files that should have been measured.
Reason: ima_path_check() got bogus value passed as mask.
[AV: mea culpa]
[AV: add missing nfsd bits]

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-02-07 03:06:22 -05:00
Al Viro
1e41568d73 Take ima_path_check() in nfsd past dentry_open() in nfsd_open()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-02-07 03:06:22 -05:00
Trond Myklebust
aa696a6f34 nfsd: Use vfs_fsync_range() in nfsd_commit
The NFS COMMIT operation allows the client to specify the exact byte range
that it wishes to sync to disk in order to optimise server performance.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-01-29 18:53:11 -05:00
Chuck Lever
37498292aa NFSD: Create PF_INET6 listener in write_ports
Try to create a PF_INET6 listener for NFSD, if IPv6 is enabled in the
kernel.

Make sure nfsd_serv's reference count is decreased if
__write_ports_addxprt() failed to create a listener.  See
__write_ports_addfd().

Our current plan is to rely on rpc.nfsd to create appropriate IPv6
listeners when server-side NFS/IPv6 support is desired.  Legacy
behavior, via the write_threads or write_svc kernel APIs, will remain
the same -- only IPv4 listeners are created.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[bfields@citi.umich.edu: Move error-handling code to end]
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-01-27 17:01:08 -05:00
Chuck Lever
6871790815 SUNRPC: NFS kernel APIs shouldn't return ENOENT for "transport not found"
write_ports() converts svc_create_xprt()'s ENOENT error return to
EPROTONOSUPPORT so that rpc.nfsd (in user space) can report an error
message that makes sense.

It turns out that several of the other kernel APIs rpc.nfsd use can
also return ENOENT from svc_create_xprt(), by way of lockd_up().

On the client side, an NFSv2 or NFSv3 mount request can also return
the result of lockd_up().  This error may also be returned during an
NFSv4 mount request, since the NFSv4 callback service uses
svc_create_xprt() to create the callback listener.  An ENOENT error
return results in a confusing error message from the mount command.

Let's have svc_create_xprt() return EPROTONOSUPPORT instead of ENOENT.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-01-26 17:59:21 -05:00
Ricardo Labiaga
8b8aae4009 nfsd41: Create the recovery entry for the NFSv4.1 client
Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-01-14 12:24:46 -05:00
Christoph Hellwig
6a68f89ee1 nfsd: use vfs_fsync for non-directories
Instead of opencoding the fsync calling sequence use vfs_fsync.  This also
gets rid of the useless i_mutex over the data writeout.

Consolidate the remaining special code for syncing directories and document
it's quirks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-01-13 09:42:26 -05:00
Ricardo Labiaga
de3cab793c nfsd4: Use FIRST_NFS4_OP in nfsd4_decode_compound()
Since we're checking for LAST_NFS4_OP, use FIRST_NFS4_OP to be consistent.

Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-01-13 09:42:26 -05:00
Ricardo Labiaga
c551866e64 nfsd41: nfsd4_decode_compound() does not recognize all ops
The server incorrectly assumes that the operations in the
array start with value 0.  The first operation (OP_ACCESS)
has a value of 3, causing the check in nfsd4_decode_compound
to be off.

Instead of comparing that the operation number is less than
the number of elements in the array, the server should verify
that it is less than the maximum valid operation number
defined by LAST_NFS4_OP.

Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-01-13 09:42:26 -05:00
Linus Torvalds
93939f4e5d Merge branch 'for-2.6.33' of git://linux-nfs.org/~bfields/linux
* 'for-2.6.33' of git://linux-nfs.org/~bfields/linux:
  sunrpc: fix peername failed on closed listener
  nfsd: make sure data is on disk before calling ->fsync
  nfsd: fix "insecure" export option
2010-01-06 18:10:15 -08:00
Christoph Hellwig
7211a4e859 nfsd: make sure data is on disk before calling ->fsync
nfsd is not using vfs_fsync, so I missed it when changing the calling
convention during the 2.6.32 window.  This patch fixes it to not only
start the data writeout, but also wait for it to complete before calling
into ->fsync.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2010-01-06 17:37:26 -05:00
J. Bruce Fields
3d354cbc43 nfsd: fix "insecure" export option
A typo in 12045a6ee9 "nfsd: let "insecure" flag vary by
pseudoflavor" reversed the sense of the "insecure" flag.

Reported-by: Michael Guntsche <mike@it-loops.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-20 20:19:51 -08:00
J. Bruce Fields
f69ac2f5a3 nfsd: fix "insecure" export option
A typo in 12045a6ee9 "nfsd: let "insecure" flag vary by
pseudoflavor" reversed the sense of the "insecure" flag.

Reported-by: Michael Guntsche <mike@it-loops.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-12-20 10:22:58 -05:00
Linus Torvalds
bac5e54c29 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (38 commits)
  direct I/O fallback sync simplification
  ocfs: stop using do_sync_mapping_range
  cleanup blockdev_direct_IO locking
  make generic_acl slightly more generic
  sanitize xattr handler prototypes
  libfs: move EXPORT_SYMBOL for d_alloc_name
  vfs: force reval of target when following LAST_BIND symlinks (try #7)
  ima: limit imbalance msg
  Untangling ima mess, part 3: kill dead code in ima
  Untangling ima mess, part 2: deal with counters
  Untangling ima mess, part 1: alloc_file()
  O_TRUNC open shouldn't fail after file truncation
  ima: call ima_inode_free ima_inode_free
  IMA: clean up the IMA counts updating code
  ima: only insert at inode creation time
  ima: valid return code from ima_inode_alloc
  fs: move get_empty_filp() deffinition to internal.h
  Sanitize exec_permission_lite()
  Kill cached_lookup() and real_lookup()
  Kill path_lookup_open()
  ...

Trivial conflicts in fs/direct-io.c
2009-12-16 12:04:02 -08:00
Al Viro
1429b3eca2 Untangling ima mess, part 3: kill dead code in ima
Kill the 'update' argument of ima_path_check(), kill
dead code in ima.

Current rules: ima counters are bumped at the same time
when the file switches from put_filp() fodder to fput()
one.  Which happens exactly in two places - alloc_file()
and __dentry_open().  Nothing else needs to do that at
all.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16 12:16:47 -05:00
Al Viro
b65a9cfc2c Untangling ima mess, part 2: deal with counters
* do ima_get_count() in __dentry_open()
* stop doing that in followups
* move ima_path_check() to right after nameidata_to_filp()
* don't bump counters on it

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16 12:16:47 -05:00
J. Bruce Fields
7663dacd92 nfsd: remove pointless paths in file headers
The new .h files have paths at the top that are now out of date.  While
we're here, just remove all of those from fs/nfsd; they never served any
purpose.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-12-15 15:01:47 -05:00
J. Bruce Fields
1557aca790 nfsd: move most of nfsfh.h to fs/nfsd
Most of this can be trivially moved to a private header as well.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-12-15 15:01:46 -05:00
J. Bruce Fields
774b147828 nfsd: make V4ROOT exports read-only
I can't see any use for writeable V4ROOT exports.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-12-15 15:01:44 -05:00
Steve Dickson
03a816b46d nfsd: restrict filehandles accepted in V4ROOT case
On V4ROOT exports, only accept filehandles that are the *root* of some
export.  This allows mountd to allow or deny access to individual
directories and symlinks on the pseudofilesystem.

Note that the checks in readdir and lookup are not enough, since a
malicious host with access to the network could guess filehandles that
they weren't able to obtain through lookup or readdir.

Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-12-15 14:07:24 -05:00
J. Bruce Fields
f2ca7153ca nfsd: allow exports of symlinks
We want to allow exports of symlinks, to allow mountd to communicate to
the kernel which symlinks lead to exports, and hence which symlinks need
to be visible on the pseudofilesystem.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-12-15 14:07:24 -05:00
J. Bruce Fields
3227fa41ab nfsd: filter readdir results in V4ROOT case
As with lookup, we treat every boject as a mountpoint and pretend it
doesn't exist if it isn't exported.

The preexisting code here is confusing, but I haven't yet figured out
how to make it clearer.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-12-15 14:07:24 -05:00
J. Bruce Fields
82ead7fe41 nfsd: filter lookup results in V4ROOT case
We treat every object as a mountpoint and pretend it doesn't exist if
it isn't exported.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-12-15 14:07:23 -05:00
J. Bruce Fields
3b6cee7bc4 nfsd4: don't continue "under" mounts in V4ROOT case
If /A/mount/point/ has filesystem "B" mounted on top of it, and if "A"
is exported, but not "B", then the nfs server has always returned to the
client a filehandle for the mountpoint, instead of for the root of "B",
allowing the client to see the subtree of "A" that would otherwise be
hidden by B.

Disable this behavior in the case of V4ROOT exports; we implement the
path restrictions of V4ROOT exports by treating *every* directory as if
it were a mountpoint, and allowing traversal *only* if the new directory
is exported.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-12-15 14:07:23 -05:00
Steve Dickson
eb4c86c6a5 nfsd: introduce export flag for v4 pseudoroot
NFSv4 differs from v2 and v3 in that it presents a single unified
filesystem tree, whereas v2 and v3 exported multiple filesystem (whose
roots could be found using a separate mount protocol).

Our original NFSv4 server implementation asked the administrator to
designate a single filesystem as the NFSv4 root, then to mount
filesystems they wished to export underneath.  (Often using bind mounts
of already-existing filesystems.)

This was conceptually simple, and allowed easy implementation, but
created a serious obstacle to upgrading between v2/v3: since the paths
to v4 filesystems were different, administrators would have to adjust
all the paths in client-side mount commands when switching to v4.

Various workarounds are possible.  For example, the administrator could
export "/" and designate it as the v4 root.  However, the security risks
of that approach are obvious, and in any case we shouldn't be requiring
the administrator to take extra steps to fix this problem; instead, the
server should present consistent paths across different versions by
default.

These patches take a modified version of that approach: we provide a new
export option which exports only a subset of a filesystem.  With this
flag, it becomes safe for mountd to export "/" by default, with no need
for additional configuration.

We begin just by defining the new flag.

Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-12-15 14:00:40 -05:00
J. Bruce Fields
12045a6ee9 nfsd: let "insecure" flag vary by pseudoflavor
This was an oversight; it should be among the export flags that can be
allowed to vary by pseudoflavor.  This allows an administrator to (for
example) allow auth_sys mounts only from low ports, but allow auth_krb5
mounts to use any port.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-12-14 19:08:58 -05:00
J. Bruce Fields
e8e8753f7a nfsd: new interface to advertise export features
Soon we will add the new V4ROOT flag, and allow the INSECURE flag to
vary by pseudoflavor.  It would be useful for nfs-utils (for example,
for improved exportfs error reporting) to be able to know when this
happens.  Use this new interface for that purpose.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-12-14 18:51:29 -05:00