Commit Graph

1087 Commits

Author SHA1 Message Date
Justin P. Mattock
70f23fd66b treewide: fix a few typos in comments
- kenrel -> kernel
- whetehr -> whether
- ttt -> tt
- sss -> ss

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-05-10 10:16:21 +02:00
Sachin Prabhu
1574dff899 Open with O_CREAT flag set fails to open existing files on non writable directories
An open on a NFS4 share using the O_CREAT flag on an existing file for
which we have permissions to open but contained in a directory with no
write permissions will fail with EACCES.

A tcpdump shows that the client had set the open mode to UNCHECKED which
indicates that the file should be created if it doesn't exist and
encountering an existing flag is not an error. Since in this case the
file exists and can be opened by the user, the NFS server is wrong in
attempting to check create permissions on the parent directory.

The patch adds a conditional statement to check for create permissions
only if the file doesn't exist.

Signed-off-by: Sachin S. Prabhu <sprabhu@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-04-20 11:03:01 -04:00
OGAWA Hirofumi
a96e5b9080 nfsd4: Fix filp leak
23fcf2ec93 (nfsd4: fix oops on lock failure)

The above patch breaks free path for stp->st_file. If stp was inserted
into sop->so_stateids, we have to free stp->st_file refcount. Because
stp->st_file refcount itself is taken whether or not any refcounts are
taken on the stp->st_file->fi_fds[].

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-04-19 17:31:13 -04:00
J. Bruce Fields
4ee63624fd nfsd4: fix struct file leak on delegation
Introduced by acfdf5c383.

Cc: stable@kernel.org
Reported-by: Gerhard Heift <ml-nfs-linux-20110412-ef47@gheift.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-04-18 13:30:56 -04:00
Linus Torvalds
18770c7c3a Merge branch 'for-2.6.39' of git://linux-nfs.org/~bfields/linux
* 'for-2.6.39' of git://linux-nfs.org/~bfields/linux:
  nfsd4: fix oops on lock failure
  nfsd: fix auth_domain reference leak on nlm operations
2011-04-11 15:45:17 -07:00
J. Bruce Fields
23fcf2ec93 nfsd4: fix oops on lock failure
Lock stateid's can have access_bmap 0 if they were only partially
initialized (due to a failed lock request); handle that case in
free_generic_stateid.

------------[ cut here ]------------
kernel BUG at fs/nfsd/nfs4state.c:380!
invalid opcode: 0000 [#1] SMP
last sysfs file: /sys/kernel/mm/ksm/run
Modules linked in: nfs fscache md4 nls_utf8 cifs ip6table_filter ip6_tables ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat bridge stp llc nfsd lockd nfs_acl auth_rpcgss sunrpc ipv6 ppdev parport_pc parport pcnet32 mii pcspkr microcode i2c_piix4 BusLogic floppy [last unloaded: mperf]

Pid: 1468, comm: nfsd Not tainted 2.6.38+ #120 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform
EIP: 0060:[<e24f180d>] EFLAGS: 00010297 CPU: 0
EIP is at nfs4_access_to_omode+0x1c/0x29 [nfsd]
EAX: ffffffff EBX: dd758120 ECX: 00000000 EDX: 00000004
ESI: dd758120 EDI: ddfe657c EBP: dd54dde0 ESP: dd54dde0
 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Process nfsd (pid: 1468, ti=dd54c000 task=ddc92580 task.ti=dd54c000)
Stack:
 dd54ddf0 e24f19ca 00000000 ddfe6560 dd54de08 e24f1a5d dd758130 deee3a20
 ddfe6560 31270000 dd54df1c e24f52fd 0000000f dd758090 e2505dd0 0be304cf
 dbb51d68 0000000e ddfe657c ddcd8020 dd758130 dd758128 dd7580d8 dd54de68
Call Trace:
 [<e24f19ca>] free_generic_stateid+0x1c/0x3e [nfsd]
 [<e24f1a5d>] release_lockowner+0x71/0x8a [nfsd]
 [<e24f52fd>] nfsd4_lock+0x617/0x66c [nfsd]
 [<e24e57b6>] ? nfsd_setuser+0x199/0x1bb [nfsd]
 [<e24e056c>] ? nfsd_setuser_and_check_port+0x65/0x81 [nfsd]
 [<c07a0052>] ? _cond_resched+0x8/0x1c
 [<c04ca61f>] ? slab_pre_alloc_hook.clone.33+0x23/0x27
 [<c04cac01>] ? kmem_cache_alloc+0x1a/0xd2
 [<c04835a0>] ? __call_rcu+0xd7/0xdd
 [<e24e0dfb>] ? fh_verify+0x401/0x452 [nfsd]
 [<e24f0b61>] ? nfsd4_encode_operation+0x52/0x117 [nfsd]
 [<e24ea0d7>] ? nfsd4_putfh+0x33/0x3b [nfsd]
 [<e24f4ce6>] ? nfsd4_delegreturn+0xd4/0xd4 [nfsd]
 [<e24ea2c9>] nfsd4_proc_compound+0x1ea/0x33e [nfsd]
 [<e24de6ee>] nfsd_dispatch+0xd1/0x1a5 [nfsd]
 [<e1d6e1c7>] svc_process_common+0x282/0x46f [sunrpc]
 [<e1d6e578>] svc_process+0xdc/0xfa [sunrpc]
 [<e24de0fa>] nfsd+0xd6/0x115 [nfsd]
 [<e24de024>] ? nfsd_shutdown+0x24/0x24 [nfsd]
 [<c0454322>] kthread+0x62/0x67
 [<c04542c0>] ? kthread_worker_fn+0x114/0x114
 [<c07a6ebe>] kernel_thread_helper+0x6/0x10
Code: eb 05 b8 00 00 27 4f 8d 65 f4 5b 5e 5f 5d c3 83 e0 03 55 83 f8 02 89 e5 74 17 83 f8 03 74 05 48 75 09 eb 09 b8 02 00 00 00 eb 0b <0f> 0b 31 c0 eb 05 b8 01 00 00 00 5d c3 55 89 e5 57 56 89 d6 8d
EIP: [<e24f180d>] nfs4_access_to_omode+0x1c/0x29 [nfsd] SS:ESP 0068:dd54dde0
---[ end trace 2b0bf6c6557cb284 ]---

The trace route is:

 -> nfsd4_lock()
   -> if (lock->lk_is_new) {
     -> alloc_init_lock_stateid()

        3739: stp->st_access_bmap = 0;

   ->if (status && lock->lk_is_new && lock_sop)
     -> release_lockowner()
      -> free_generic_stateid()
       -> nfs4_access_bmap_to_omode()
          -> nfs4_access_to_omode()

        380: BUG();   *****

This problem was introduced by 0997b17360.

Reported-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Tested-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-04-10 12:21:27 -04:00
Lucas De Marchi
25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
J. Bruce Fields
954032d252 nfsd: fix auth_domain reference leak on nlm operations
This was noticed by users who performed more than 2^32 lock operations
and hence made this counter overflow (eventually leading to
use-after-free's).  Setting rq_client to NULL here means that it won't
later get auth_domain_put() when it should be.

Appears to have been introduced in 2.5.42 by "[PATCH] kNFSd: Move auth
domain lookup into svcauth" which moved most of the rq_client handling
to common svcauth code, but left behind this one line.

Cc: Neil Brown <neilb@suse.de>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-24 23:11:27 -04:00
Linus Torvalds
dc87c55120 Merge branch 'for-2.6.39' of git://linux-nfs.org/~bfields/linux
* 'for-2.6.39' of git://linux-nfs.org/~bfields/linux:
  SUNRPC: Remove resource leak in svc_rdma_send_error()
  nfsd: wrong index used in inner loop
  nfsd4: fix comment and remove unused nfsd4_file fields
  nfs41: make sure nfs server return right ca_maxresponsesize_cached
  nfsd: fix compile error
  svcrpc: fix bad argument in unix_domain_find
  nfsd4: fix struct file leak
  nfsd4: minor nfs4state.c reshuffling
  svcrpc: fix rare race on unix_domain creation
  nfsd41: modify the members value of nfsd4_op_flags
  nfsd: add proc file listing kernel's gss_krb5 enctypes
  gss:krb5 only include enctype numbers in gm_upcall_enctypes
  NFSD, VFS: Remove dead code in nfsd_rename()
  nfsd: kill unused macro definition
  locks: use assign_type()
2011-03-24 08:20:39 -07:00
Al Viro
7cc90cc3ff don't pass 'mounting_here' flag to follow_down()
it's always false now

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-18 09:04:20 -04:00
Mi Jinlong
5a02ab7c3c nfsd: wrong index used in inner loop
We must not use dummy for index.
After the first index, READ32(dummy) will change dummy!!!!

Signed-off-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
[bfields@redhat.com: Trond points out READ_BUF alone is sufficient.]
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-17 13:09:19 -04:00
J. Bruce Fields
cf507b6f8e Merge create_session decoding fix into for-2.6.39
This needs a further fixup!
2011-03-17 13:07:25 -04:00
J. Bruce Fields
9ae78bcc00 nfsd4: fix comment and remove unused nfsd4_file fields
A couple fields here were left over from a previous version of a patch,
and are no longer used.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-17 12:52:33 -04:00
Mi Jinlong
d2b217439f nfs41: make sure nfs server return right ca_maxresponsesize_cached
According to rfc5661,

  ca_maxresponsesize_cached:

     Like ca_maxresponsesize, but the maximum size of a reply that
     will be stored in the reply cache (Section 2.10.6.1).  For each
     channel, the server MAY decrease this value, but MUST NOT
     increase it.

the latest kernel(2.6.38-rc8) may increase the value for ignoring
request's ca_maxresponsesize_cached value. We should not ignore it.

Signed-off-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-16 11:10:22 -04:00
J. Bruce Fields
0a5e5f122c nfsd: fix compile error
"fs/built-in.o: In function `supported_enctypes_show':
nfsctl.c:(.text+0x7beb0): undefined reference to `gss_mech_get_by_name'
nfsctl.c:(.text+0x7bebc): undefined reference to `gss_mech_put'
"

Reported-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-14 20:57:44 -04:00
roel
3ec07aa952 nfsd: wrong index used in inner loop
Index i was already used in the outer loop

Cc: stable@kernel.org
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-08 19:46:10 -05:00
J. Bruce Fields
0997b17360 nfsd4: fix struct file leak
Make sure we properly reference count the struct files that a lock
depends on, and release them when the lock stateid is released.

This fixes a major leak of struct files when using locking over nfsv4.

Cc: stable@kernel.org
Reported-by: Rick Koshi <nfs-bug-report@more-right-rudder.com>
Tested-by: Ivo Přikryl <prikryl@eurosat.cz>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-08 19:38:27 -05:00
J. Bruce Fields
529d7b2a7f nfsd4: minor nfs4state.c reshuffling
Minor cleanup in preparation for a bugfix--moving some code to avoid
forward references, etc.  No change in functionality.

Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-08 19:38:15 -05:00
Mi Jinlong
5ece3cafbd nfsd41: modify the members value of nfsd4_op_flags
The members of nfsd4_op_flags, (ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS)
equals to  ALLOWED_AS_FIRST_OP, maybe that's not what we want.

OP_PUTROOTFH with op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,
can't appears as the first operation with out SEQUENCE ops.

This patch modify the wrong value of ALLOWED_WITHOUT_FH etc which
was introduced by f9bb94c4.

Cc: stable@kernel.org
Reviewed-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-07 12:10:33 -05:00
Kevin Coffman
b0b0c0a26e nfsd: add proc file listing kernel's gss_krb5 enctypes
Add a new proc file which lists the encryption types supported
by the kernel's gss_krb5 code.

Newer MIT Kerberos libraries support the assertion of acceptor
subkeys.  This enctype information allows user-land (svcgssd)
to request that the Kerberos libraries limit the encryption
types that it uses when generating the subkeys.

Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-07 12:06:48 -05:00
Jesper Juhl
46d4cef9cf NFSD, VFS: Remove dead code in nfsd_rename()
Currently we have the following code in fs/nfsd/vfs.c::nfsd_rename() :

	...
	host_err = nfsd_break_lease(odentry->d_inode);
	if (host_err)
		goto out_drop_write;
	if (ndentry->d_inode) {
		host_err = nfsd_break_lease(ndentry->d_inode);
		if (host_err)
			goto out_drop_write;
	}
	if (host_err)
		goto out_drop_write;
	...

'host_err' is guaranteed to be 0 by the time we test 'ndentry->d_inode'.
If 'host_err' becomes != 0 inside the 'if' statement, then we goto
'out_drop_write'. So, after the 'if' statement there is no way that
'host_err' can be anything but 0, so the test afterwards is just dead
code.
This patch removes the dead code.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-07 12:05:14 -05:00
Shan Wei
35079582e7 nfsd: kill unused macro definition
These macros had never been used for several years.
So, remove them.

Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-07 12:05:09 -05:00
J. Bruce Fields
32b007b4e1 nfsd4: fix bad pointer on failure to find delegation
In case of a nonempty list, the return on error here is obviously bogus;
it ends up being a pointer to the list head instead of to any valid
delegation on the list.

In particular, if nfsd4_delegreturn() hits this case, and you're quite unlucky,
then renew_client may oops, and it may take an embarassingly long time to
figure out why.  Facepalm.

BUG: unable to handle kernel NULL pointer dereference at 0000000000000090
IP: [<ffffffff81292965>] nfsd4_delegreturn+0x125/0x200
...

Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-03-07 11:44:53 -05:00
Benny Halevy
2c9c8f36c3 NFSD: fix decode_cb_sequence4resok
Fix bug introduced in patch
85a56480 NFSD: Update XDR decoders in NFSv4 callback client

Although decode_cb_sequence4resok ignores highest slotid and target highest slotid
it must account for their space in their xdr stream when calling xdr_inline_decode

Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-22 15:55:09 -08:00
NeilBrown
47c85291d3 nfsd: correctly handle return value from nfsd_map_name_to_*
These functions return an nfs status, not a host_err.  So don't
try to convert  before returning.

This is a regression introduced by
3c726023402a2f3b28f49b9d90ebf9e71151157d; I fixed up two of the callers,
but missed these two.

Cc: stable@kernel.org
Reported-by: Herbert Poetzl <herbert@13thfloor.at>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-16 18:31:05 -05:00
J. Bruce Fields
83f6b0c182 nfsd: break lease on unlink due to rename
4795bb37ef "nfsd: break lease on unlink,
link, and rename", only broke the lease on the file that was being
renamed, and didn't handle the case where the target path refers to an
already-existing file that will be unlinked by a rename--in that case
the target file should have any leases broken as well.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-14 10:35:19 -05:00
J. Bruce Fields
acfdf5c383 nfsd4: acquire only one lease per file
Instead of acquiring one lease each time another client opens a file,
nfsd can acquire just one lease to represent all of them, and reference
count it to determine when to release it.

This fixes a regression introduced by
c45821d263 "locks: eliminate fl_mylease
callback": after that patch, only the struct file * is used to determine
who owns a given lease.  But since we recently converted the server to
share a single struct file per open, if we acquire multiple leases on
the same file from nfsd, it then becomes impossible on unlocking a lease
to determine which of those leases (all of whom share the same struct
file *) we meant to remove.

Thanks to Takashi Iwai <tiwai@suse.de> for catching a bug in a previous
version of this patch.

Tested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-14 10:35:19 -05:00
J. Bruce Fields
5d926e8c2f nfsd4: modify fi_delegations under recall_lock
Modify fi_delegations only under the recall_lock, allowing us to use
that list on lease breaks.

Also some trivial cleanup to simplify later changes.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-14 10:35:19 -05:00
J. Bruce Fields
65bc58f518 nfsd4: remove unused deleg dprintk's.
These aren't all that useful, and get in the way of the next steps.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-14 10:35:19 -05:00
J. Bruce Fields
edab9782b5 nfsd4: split lease setting into separate function
Splitting some code into a separate function which we'll be adding some
more to.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-14 10:35:18 -05:00
J. Bruce Fields
dd239cc05f nfsd4: fix leak on allocation error
Also share some common exit code.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-14 10:35:18 -05:00
J. Bruce Fields
22d38c4c10 nfsd4: add helper function for lease setup
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-14 10:35:18 -05:00
J. Bruce Fields
6b57d9c86d nfsd4: split up nfsd_break_deleg_cb
We'll be adding some more code here soon.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-14 10:35:18 -05:00
Konstantin Khorenko
3aa6e0aa8a NFSD: memory corruption due to writing beyond the stat array
If nfsd fails to find an exported via NFS file in the readahead cache, it
should increment corresponding nfsdstats counter (ra_depth[10]), but due to a
bug it may instead write to ra_depth[11], corrupting the following field.

In a kernel with NFSDv4 compiled in the corruption takes the form of an
increment of a counter of the number of NFSv4 operation 0's received; since
there is no operation 0, this is harmless.

In a kernel with NFSDv4 disabled it corrupts whatever happens to be in the
memory beyond nfsdstats.

Signed-off-by: Konstantin Khorenko <khorenko@openvz.org>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-14 10:35:18 -05:00
Benny Halevy
0af3f814cc NFSD: use nfserr for status after decode_cb_op_status
Bugs introduced in 85a5648019
"NFSD: Update XDR decoders in NFSv4 callback client"

Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-14 10:35:18 -05:00
J. Bruce Fields
541ce98c10 nfsd: don't leak dentry count on mnt_want_write failure
The exit cleanup isn't quite right here.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-02-14 10:31:08 -05:00
Linus Torvalds
f8206b925f Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (23 commits)
  sanitize vfsmount refcounting changes
  fix old umount_tree() breakage
  autofs4: Merge the remaining dentry ops tables
  Unexport do_add_mount() and add in follow_automount(), not ->d_automount()
  Allow d_manage() to be used in RCU-walk mode
  Remove a further kludge from __do_follow_link()
  autofs4: Bump version
  autofs4: Add v4 pseudo direct mount support
  autofs4: Fix wait validation
  autofs4: Clean up autofs4_free_ino()
  autofs4: Clean up dentry operations
  autofs4: Clean up inode operations
  autofs4: Remove unused code
  autofs4: Add d_manage() dentry operation
  autofs4: Add d_automount() dentry operation
  Remove the automount through follow_link() kludge code from pathwalk
  CIFS: Use d_automount() rather than abusing follow_link()
  NFS: Use d_automount() rather than abusing follow_link()
  AFS: Use d_automount() rather than abusing follow_link()
  Add an AT_NO_AUTOMOUNT flag to suppress terminal automount
  ...
2011-01-16 11:31:50 -08:00
David Howells
cc53ce53c8 Add a dentry op to allow processes to be held during pathwalk transit
Add a dentry op (d_manage) to permit a filesystem to hold a process and make it
sleep when it tries to transit away from one of that filesystem's directories
during a pathwalk.  The operation is keyed off a new dentry flag
(DCACHE_MANAGE_TRANSIT).

The filesystem is allowed to be selective about which processes it holds and
which it permits to continue on or prohibits from transiting from each flagged
directory.  This will allow autofs to hold up client processes whilst letting
its userspace daemon through to maintain the directory or the stuff behind it
or mounted upon it.

The ->d_manage() dentry operation:

	int (*d_manage)(struct path *path, bool mounting_here);

takes a pointer to the directory about to be transited away from and a flag
indicating whether the transit is undertaken by do_add_mount() or
do_move_mount() skipping through a pile of filesystems mounted on a mountpoint.

It should return 0 if successful and to let the process continue on its way;
-EISDIR to prohibit the caller from skipping to overmounted filesystems or
automounting, and to use this directory; or some other error code to return to
the user.

->d_manage() is called with namespace_sem writelocked if mounting_here is true
and no other locks held, so it may sleep.  However, if mounting_here is true,
it may not initiate or wait for a mount or unmount upon the parameter
directory, even if the act is actually performed by userspace.

Within fs/namei.c, follow_managed() is extended to check with d_manage() first
on each managed directory, before transiting away from it or attempting to
automount upon it.

follow_down() is renamed follow_down_one() and should only be used where the
filesystem deliberately intends to avoid management steps (e.g. autofs).

A new follow_down() is added that incorporates the loop done by all other
callers of follow_down() (do_add/move_mount(), autofs and NFSD; whilst AFS, NFS
and CIFS do use it, their use is removed by converting them to use
d_automount()).  The new follow_down() calls d_manage() as appropriate.  It
also takes an extra parameter to indicate if it is being called from mount code
(with namespace_sem writelocked) which it passes to d_manage().  follow_down()
ignores automount points so that it can be used to mount on them.

__follow_mount_rcu() is made to abort rcu-walk mode if it hits a directory with
DCACHE_MANAGE_TRANSIT set on the basis that we're probably going to have to
sleep.  It would be possible to enter d_manage() in rcu-walk mode too, and have
that determine whether to abort or not itself.  That would allow the autofs
daemon to continue on in rcu-walk mode.

Note that DCACHE_MANAGE_TRANSIT on a directory should be cleared when it isn't
required as every tranist from that directory will cause d_manage() to be
invoked.  It can always be set again when necessary.

==========================
WHAT THIS MEANS FOR AUTOFS
==========================

Autofs currently uses the lookup() inode op and the d_revalidate() dentry op to
trigger the automounting of indirect mounts, and both of these can be called
with i_mutex held.

autofs knows that the i_mutex will be held by the caller in lookup(), and so
can drop it before invoking the daemon - but this isn't so for d_revalidate(),
since the lock is only held on _some_ of the code paths that call it.  This
means that autofs can't risk dropping i_mutex from its d_revalidate() function
before it calls the daemon.

The bug could manifest itself as, for example, a process that's trying to
validate an automount dentry that gets made to wait because that dentry is
expired and needs cleaning up:

	mkdir         S ffffffff8014e05a     0 32580  24956
	Call Trace:
	 [<ffffffff885371fd>] :autofs4:autofs4_wait+0x674/0x897
	 [<ffffffff80127f7d>] avc_has_perm+0x46/0x58
	 [<ffffffff8009fdcf>] autoremove_wake_function+0x0/0x2e
	 [<ffffffff88537be6>] :autofs4:autofs4_expire_wait+0x41/0x6b
	 [<ffffffff88535cfc>] :autofs4:autofs4_revalidate+0x91/0x149
	 [<ffffffff80036d96>] __lookup_hash+0xa0/0x12f
	 [<ffffffff80057a2f>] lookup_create+0x46/0x80
	 [<ffffffff800e6e31>] sys_mkdirat+0x56/0xe4

versus the automount daemon which wants to remove that dentry, but can't
because the normal process is holding the i_mutex lock:

	automount     D ffffffff8014e05a     0 32581      1              32561
	Call Trace:
	 [<ffffffff80063c3f>] __mutex_lock_slowpath+0x60/0x9b
	 [<ffffffff8000ccf1>] do_path_lookup+0x2ca/0x2f1
	 [<ffffffff80063c89>] .text.lock.mutex+0xf/0x14
	 [<ffffffff800e6d55>] do_rmdir+0x77/0xde
	 [<ffffffff8005d229>] tracesys+0x71/0xe0
	 [<ffffffff8005d28d>] tracesys+0xd5/0xe0

which means that the system is deadlocked.

This patch allows autofs to hold up normal processes whilst the daemon goes
ahead and does things to the dentry tree behind the automouter point without
risking a deadlock as almost no locks are held in d_manage() and none in
d_automount().

Signed-off-by: David Howells <dhowells@redhat.com>
Was-Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-15 20:07:31 -05:00
Linus Torvalds
18bce371ae Merge branch 'for-2.6.38' of git://linux-nfs.org/~bfields/linux
* 'for-2.6.38' of git://linux-nfs.org/~bfields/linux: (62 commits)
  nfsd4: fix callback restarting
  nfsd: break lease on unlink, link, and rename
  nfsd4: break lease on nfsd setattr
  nfsd: don't support msnfs export option
  nfsd4: initialize cb_per_client
  nfsd4: allow restarting callbacks
  nfsd4: simplify nfsd4_cb_prepare
  nfsd4: give out delegations more quickly in 4.1 case
  nfsd4: add helper function to run callbacks
  nfsd4: make sure sequence flags are set after destroy_session
  nfsd4: re-probe callback on connection loss
  nfsd4: set sequence flag when backchannel is down
  nfsd4: keep finer-grained callback status
  rpc: allow xprt_class->setup to return a preexisting xprt
  rpc: keep backchannel xprt as long as server connection
  rpc: move sk_bc_xprt to svc_xprt
  nfsd4: allow backchannel recovery
  nfsd4: support BIND_CONN_TO_SESSION
  nfsd4: modify session list under cl_lock
  Documentation: fl_mylease no longer exists
  ...

Fix up conflicts in fs/nfsd/vfs.c with the vfs-scale work.  The
vfs-scale work touched some msnfs cases, and this merge removes support
for that entirely, so the conflict was trivial to resolve.
2011-01-14 13:17:26 -08:00
J. Bruce Fields
a8f2800b4f nfsd4: fix callback restarting
Ensure a new callback is added to the client's list of callbacks at most
once.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-01-14 14:51:31 -05:00
J. Bruce Fields
4795bb37ef nfsd: break lease on unlink, link, and rename
Any change to any of the links pointing to an entry should also break
delegations.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-01-13 21:04:09 -05:00
J. Bruce Fields
6a76bebefe nfsd4: break lease on nfsd setattr
Leases (delegations) should really be broken on any metadata change, not
just on size change.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-01-13 21:04:08 -05:00
J. Bruce Fields
9ce137eee4 nfsd: don't support msnfs export option
We've long had these pointless #ifdef MSNFS's sprinkled throughout the
code--pointless because MSNFS is always defined (and we give no config
option to make that easy to change).  So we could just remove the
ifdef's and compile the resulting code unconditionally.

But as long as we're there: why not just rip out this code entirely?
The only purpose is to implement the "msnfs" export option which turns
on Windows-like behavior in some cases, and:

	- the export option isn't documented anywhere;
	- the userland utilities (which would need to be able to parse
	  "msnfs" in an export file) don't support it;
	- I don't know how to maintain this, as I don't know what the
	  proper behavior is; and
	- google shows no evidence that anyone has ever used this.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-01-13 21:04:07 -05:00
J. Bruce Fields
9ee1ba5402 nfsd4: initialize cb_per_client
Otherwise a callback that is aborted before it runs will result in a
list_del on an uninitialized list head.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-01-13 21:04:06 -05:00
Linus Torvalds
275220f0fc Merge branch 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block: (43 commits)
  block: ensure that completion error gets properly traced
  blktrace: add missing probe argument to block_bio_complete
  block cfq: don't use atomic_t for cfq_group
  block cfq: don't use atomic_t for cfq_queue
  block: trace event block fix unassigned field
  block: add internal hd part table references
  block: fix accounting bug on cross partition merges
  kref: add kref_test_and_get
  bio-integrity: mark kintegrityd_wq highpri and CPU intensive
  block: make kblockd_workqueue smarter
  Revert "sd: implement sd_check_events()"
  block: Clean up exit_io_context() source code.
  Fix compile warnings due to missing removal of a 'ret' variable
  fs/block: type signature of major_to_index(int) to major_to_index(unsigned)
  block: convert !IS_ERR(p) && p to !IS_ERR_NOR_NULL(p)
  cfq-iosched: don't check cfqg in choose_service_tree()
  fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors
  cdrom: export cdrom_check_events()
  sd: implement sd_check_events()
  sr: implement sr_check_events()
  ...
2011-01-13 10:45:01 -08:00
Linus Torvalds
b9d919a4ac Merge branch 'nfs-for-2.6.38' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
* 'nfs-for-2.6.38' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6: (89 commits)
  NFS fix the setting of exchange id flag
  NFS: Don't use vm_map_ram() in readdir
  NFSv4: Ensure continued open and lockowner name uniqueness
  NFS: Move cl_delegations to the nfs_server struct
  NFS: Introduce nfs_detach_delegations()
  NFS: Move cl_state_owners and related fields to the nfs_server struct
  NFS: Allow walking nfs_client.cl_superblocks list outside client.c
  pnfs: layout roc code
  pnfs: update nfs4_callback_recallany to handle layouts
  pnfs: add CB_LAYOUTRECALL handling
  pnfs: CB_LAYOUTRECALL xdr code
  pnfs: change lo refcounting to atomic_t
  pnfs: check that partial LAYOUTGET return is ignored
  pnfs: add layout to client list before sending rpc
  pnfs: serialize LAYOUTGET(openstateid)
  pnfs: layoutget rpc code cleanup
  pnfs: change how lsegs are removed from layout list
  pnfs: change layout state seqlock to a spinlock
  pnfs: add prefix to struct pnfs_layout_hdr fields
  pnfs: add prefix to struct pnfs_layout_segment fields
  ...
2011-01-11 15:11:56 -08:00
J. Bruce Fields
5ce8ba25d6 nfsd4: allow restarting callbacks
If we lose the backchannel and then the client repairs the problem,
resend any callbacks.

We use a new cb_done flag to track whether there is still work to be
done for the callback or whether it can be destroyed with the rpc.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-01-11 15:04:11 -05:00
J. Bruce Fields
3ff3600e7e nfsd4: simplify nfsd4_cb_prepare
Remove handling for a nonexistant case (status && !-EAGAIN).

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-01-11 15:04:11 -05:00
J. Bruce Fields
14a24e99f4 nfsd4: give out delegations more quickly in 4.1 case
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-01-11 15:04:11 -05:00
J. Bruce Fields
229b2a0839 nfsd4: add helper function to run callbacks
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-01-11 15:04:11 -05:00