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takes vfsmount and relative path, does lookup within that vfsmount
(possibly triggering automounts) and returns the result as root
of subtree suitable for return by ->mount() (i.e. a reference to
dentry and an active reference to its superblock grabbed, superblock
locked exclusive).

btrfs and nfs switched to it instead of open-coding the sucker.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Life is much saner if create_mnt_ns(mnt) drops mnt in case of error...
Switch it to such calling conventions, switch callers, fix double mntput() in
fs/nfs/super.c one.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

commit ae50c0b5

 "pnfs: client stats" added additional information to
the output of /proc/self/mountstats. The new functions introduced are
only used in this file and should be marked static.

If CONFIG_NFS_V4_1 is not defined, empty stub functions are used.  If
CONFIG_NFS_V4 is not defined these stub functions are not used at all.
Adding static for the functions results in compile warnings:

fs/nfs/super.c:743: warning: 'show_sessions' defined but not used
fs/nfs/super.c:756: warning: 'show_pnfs' defined but not used

Fix this by adding a #ifdef CONFIG_NFS_V4 guard around the two
show_ functions.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

The concensus seems to be that system calls such as stat() etc should
not trigger an automount.  Neither should the l* versions.

This patch therefore adds a LOOKUP_AUTOMOUNT flag to tag those lookups
that _should_ trigger an automount on the last path element.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
[ Edited to leave out the cases that are already covered by LOOKUP_OPEN,
  LOOKUP_DIRECTORY and LOOKUP_CREATE - all of which also fundamentally
  force automounting for their own reasons   - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Do not allow multiple mounts on same mountpoint when using -o noac

When you normally attempt to mount a share twice on the same mountpoint,
a check in do_add_mount causes it to return an error

# mount localhost:/nfsv3 /mnt
# mount localhost:/nfsv3 /mnt
mount.nfs: /mnt is already mounted or busy

However when using the option 'noac', the user is able to mount the same
share on the same mountpoint multiple times. This happens because a
share mounted with the noac option is automatically assigned the 'sync'
flag MS_SYNCHRONOUS in nfs_initialise_sb(). This flag is set after the
check for already existing superblocks is done in sget(). The check for
the mount flags in nfs_compare_mount_options() does not take into
account the 'sync' flag applied later on in the code path. This means
that when using 'noac', a new superblock structure is assigned for every
new mount of the same share and multiple shares on the same mountpoint
are allowed.

ie.
# mount -onoac localhost:/nfsv3 /mnt
can be run multiple times.

The patch checks for noac and assigns the sync flag before sget() is
called to obtain an already existing superblock structure.
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

A pNFS client auto-negotiates a lot of features (minorversion level,
pNFS layout type, etc.).  This is convenient, but makes certain kinds of
failures hard for a user to detect.

For example, if the client falls back on 4.0, or falls back to MDS IO
because the user didn't connect to the right iscsi disks before
mounting, the only symptoms may be reduced performance, which may not be
noticed till long after the actual failure, and may be difficult for a
user to diagnose.

However, such "failures" may also be perfectly normal in some cases, so
we don't want to spam the system logs with them.

One approach would be to put some more information into
/proc/self/mountstats.
Signed-off-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[pnfs: add commit client stats]
[fixup data types for "ret" variables in pnfs_try_to* inline funcs.]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[fix definition of show_pnfs for !CONFIG_PNFS]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfs41: Fix show_sessions in the not CONFIG_NFS_V4_1 case]
    There is a build error when CONFIG_NFS_V4 is set but
    CONFIG_NFS_V4_1 is *not* set. show_sessions() prototype
    was unbalanced between the two cases.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
[pnfs: super.c remove CONFIG_PNFS]
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>

On a remount, the VFS layer will clear the MS_SYNCHRONOUS bit on the
assumption that the flags on the mount syscall will have it set if the
remounted fs is supposed to keep it.

In the case of "noac" though, MS_SYNCHRONOUS is implied. A remount of
such a mount will lose the MS_SYNCHRONOUS flag since "sync" isn't part
of the mount options.
Reported-by: Max Matveev <makc@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

We were always attempting sec flavor negotiation, even if the user
told us a specific sec flavor to use.  If that sec flavor fails,
we should return an error rather than continuing with sec flavor
negotiation.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

In fs/nfs/super.c::nfs_fs_mount() we test for a NULL 'data':

...
 		if (data == NULL || mntfh == NULL)
 			goto out_free_fh;
...

and then further down in the function we test 'data' again:

...
 			nfs_fscache_get_super_cookie(
 				s, data ? data->fscache_uniq : NULL, NULL);
...

this second check is just dead code since there is no way 'data' could
possibly be NULL here.
We also rely on a non-NULL 'data' in more than one location between these
two tests, further proving the point that the second test is bogus.

This patch removes the dead code.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

The last remaining instances of ->get_sb() can be converted ->mount()
now - nothing in them uses new vfsmount anymore.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

now we can do that - nobody cares about its value anymore.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

a) ->show_devname(m, mnt) - what to put into devname columns in mounts,
mountinfo and mountstats
b) ->show_path(m, mnt) - what to put into relative path column in mountinfo

Leaving those NULL gives old behaviour.  NFS switched to using those.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

part 3: now we have everything to get nfs_path() just by dentry -
just follow to (disconnected) root and pick the rest of the thing
there.

Start killing propagation of struct vfsmount * on the paths that
used to bring it to nfs_path().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

step 1 of ->mnt_devname fixes: make sure we have the value of devname
available in ..._get_root().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Factor out some cut-and-paste code in options parsing.
Saves about 800 bytes on x86-64.
Signed-off-by: Rob Landley <rlandley@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Eliminate two mostly duplicate functions (nfs_parse_simple_hostname()
and nfs_parse_protected_hostname()) and instead just make the calling
function (nfs_parse_devname()) do everything.
Signed-off-by: Rob Landley <rlandley@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This patch make nfsv4 use the generic xattr handling code
to get the nfsv4 acl. This will help us to add richacl
support to nfsv4 in later patches
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

We want to skip VFS applying mode for NFS. So set MS_POSIXACL always
and selectively use umask. Ideally we would want to use umask only
when we don't have inheritable ACEs set. But NFS currently don't
allow to send umask to the server. So this is best what we can do
and this is consistent with NFSv3
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Update: added check for zero value as it was before (note: can't simply check
mountd_port for positive value because it's typeof unsigned short)

Default value for mount server port is set to NFS_UNSPEC_PORT (-1) and will not
be changed during parsing mount options for mound data version 6. This default
value will be showed for mountport in /proc/mounts always since current default
check is for zero value. This small mistake leads to big problem, because
during umount.nfs execution from old user-space utils (at least nfs-utils
1.0.9) this value will be used as the server port to connect to. This request
will be rejected (since port is 65535) and thus nfs mount point can't be
unmounted.

Note from Chuck Lever (chuck.lever@oracle.com): this is only possible if
/etc/mtab is a link to /proc/mounts.  Not all systems have this configuration.
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

  When nfs client(kernel) don't support NFSv4, maybe user build
  kernel without NFSv4, there is a problem.

  Using command "mount SERVER-IP:/nfsv3 /mnt/" to mount NFSv3
  filesystem, mount should should success, but fail and get error:

    "mount.nfs: an incorrect mount option was specified"

  System call mount "nfs"(not "nfs4") with "vers=4",
  if CONFIG_NFS_V4 is not defined, the "vers=4" will be parsed
  as invalid argument and kernel return EINVAL to nfs-utils.

  About that, we really want get EPROTONOSUPPORT rather than
  EINVAL. This path make sure kernel parses argument success,
  and return EPROTONOSUPPORT at nfs_validate_mount_data().
Signed-off-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

The big kernel lock has been removed from all these files at some point,
leaving only the #include.

Remove this too as a cleanup.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Trying to mount NFS (root partition in my case) fails if CONFIG_NFS_V3
is not selected. nfs_validate_mount_data() returns EPROTONOSUPPORT,
because of this check:

#ifndef CONFIG_NFS_V3
	if (args->version == 3)
		goto out_v3_not_compiled;
#endif /* !CONFIG_NFS_V3 */

and args->version was always initialized to 3.

It was working in 2.6.36
Signed-off-by: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Display the status of 'local_lock' mount option in /proc/mounts.
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS clients since 2.6.12 support flock locks by emulating fcntl byte-range
locks. Due to this, some windows applications which seem to use both flock
(share mode lock mapped as flock by Samba) and fcntl locks sequentially on
the same file, can't lock as they falsely assume the file is already locked.
The problem was reported on a setup with windows clients accessing excel files
on a Samba exported share which is originally a NFS mount from a NetApp filer.

Older NFS clients (< 2.6.12) did not see this problem as flock locks were
considered local. To support legacy flock behavior, this patch adds a mount
option "-olocal_lock=" which can take the following values:

   'none'  		- Neither flock locks nor POSIX locks are local
   'flock' 		- flock locks are local
   'posix' 		- fcntl/POSIX locks are local
   'all'		- Both flock locks and POSIX locks are local

Testing:

   - This patch was tested by using -olocal_lock option with different values
     and the NLM calls were noted from the network packet captured.

     'none'  - NLM calls were seen during both flock() and fcntl(), flock lock
   	       was granted, fcntl was denied
     'flock' - no NLM calls for flock(), NLM call was seen for fcntl(),
   	       granted
     'posix' - NLM call was seen for flock() - granted, no NLM call for fcntl()
     'all'   - no NLM calls were seen during both flock() and fcntl()

   - No bugs were seen during NFSv4 locking/unlocking in general and NFSv4
     reboot recovery.

Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Hi,

An NFS client executes a statfs("file", &buff) call.
"file" exists / existed, the client has read / written it,
but it has already closed it.

user_path(pathname, &path) looks up "file" successfully in the
directory-cache  and restarts the aging timer of the directory-entry.
Even if "file" has already been removed from the server, because the
lookupcache=positive option I use, keeps the entries valid for a while.

nfs_statfs() returns ESTALE if "file" has already been removed from the
server.

If the user application repeats the statfs("file", &buff) call, we
are stuck: "file" remains young forever in the directory-cache.
Signed-off-by: Zoltan Menyhart  <Zoltan.Menyhart@bull.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org

Running "cat /proc/mounts" fails to display the "lookupcache" option.
This oversight cost me a bunch of wasted time recently.

The following simple patch fixes it.

CC: stable <stable@kernel.org>
Signed-off-by: Patrick LoPresti <lopresti@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Add a flag so we know if we mounted the NFS server using the legacy
binary interface.  If we used the legacy interface, then we should not
show the mountd options.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Currently, we do not display the minor version mount parameter in the
/proc mount info.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org

- C99 knows about USHRT_MAX/SHRT_MAX/SHRT_MIN, not
  USHORT_MAX/SHORT_MAX/SHORT_MIN.

- Make SHRT_MIN of type s16, not int, for consistency.

[akpm@linux-foundation.org: fix drivers/dma/timb_dma.c]
[akpm@linux-foundation.org: fix security/keys/keyring.c]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Clean up: fscache_uniq takes a string, so it should be included
with the other string mount option definitions, by convention.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Use the new helper functions instead of open coding.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Keep a global count of how many referrals that the current task has
traversed on a path lookup. Return ELOOP if the count exceeds
MAX_NESTED_LINKS.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

With CONFIG_NFS_V4 and data version 4, nfs_get_sb will allocate memory for
export_path in nfs4_validate_text_mount_data, so we need to free it then.
This is addressed in following kmemleak report:

unreferenced object 0xffff88016bf48a50 (size 16):
  comm "mount.nfs", pid 22567, jiffies 4651574704 (age 175471.200s)
  hex dump (first 16 bytes):
    2f 6f 70 74 2f 77 6f 72 6b 00 6b 6b 6b 6b 6b a5  /opt/work.kkkkk.
  backtrace:
    [<ffffffff814b34f9>] kmemleak_alloc+0x60/0xa7
    [<ffffffff81102c76>] kmemleak_alloc_recursive.clone.5+0x1b/0x1d
    [<ffffffff811046b3>] __kmalloc_track_caller+0x18f/0x1b7
    [<ffffffff810e1b08>] kstrndup+0x37/0x54
    [<ffffffffa0336971>] nfs_parse_devname+0x152/0x204 [nfs]
    [<ffffffffa0336af3>] nfs4_validate_text_mount_data+0xd0/0xdc [nfs]
    [<ffffffffa0338deb>] nfs_get_sb+0x325/0x736 [nfs]
    [<ffffffff81113671>] vfs_kern_mount+0xbd/0x17c
    [<ffffffff81113798>] do_kern_mount+0x4d/0xed
    [<ffffffff81129a87>] do_mount+0x787/0x7fe
    [<ffffffff81129b86>] sys_mount+0x88/0xc2
    [<ffffffff81009b42>] system_call_fastpath+0x16/0x1b
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Benny Halevy <bhalevy@panasas.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>