xfs_fs_vcmn_err can be called under a spinlock, but does a sleeping memory
allocation to create buffer for it's internal sprintf.  Fortunately it's
the only caller of icmn_err, so we can merge the two and have one single
static buffer and spinlock protecting it.  While we're at it make sure
we proper __attribute__ format annotations so that the compiler can detect
mismatched format strings.
Reported-by: NAlexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NEric Sandeen <sandeen@sandeen.net>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Speculative allocation beyond eof doesn't work properly.  It was
broken some time ago after a code cleanup that moved what is now
xfs_iomap_eof_align_last_fsb() and xfs_iomap_eof_want_preallocate()
out of xfs_iomap_write_delay() into separate functions.  The code
used to use the current file size in various checks but got changed
to be max(file_size, i_new_size).  Since i_new_size is the result
of 'offset + count' then in xfs_iomap_eof_want_preallocate() the
check for '(offset + count) <= isize' will always be true.

ie if 'offset + count' is > ip->i_size then isize will be i_new_size
and equal to 'offset + count'.

This change fixes all the places that used to use the current file
size.
Reviewed-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Code does nothing so remove it.
Reviewed-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

We should be using the incore inode size here not the linux inode
size.  The incore inode size is always up to date for directories
whereas the linux inode size is not updated for directories.

We've hit assertions in xfs_bmap() and traced it back to the linux
inode size being zero but the incore size being correct.
Reviewed-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Since v9ses->uid is unsigned, it would seem better to use simple_strtoul that
simple_strtol.

A simplified version of the semantic patch that makes this change is as
follows: (http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r2@
long e;
position p;
@@

e = simple_strtol@p(...)

@@
position p != r2.p;
type T;
T e;
@@

e =
- simple_strtol@p
+ simple_strtoul
  (...)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Acked-by: NEric Van Hensbergen <ericvh@gmail.com>

d_iname is rubbish for long file names.
Use d_name.name in printks instead.
Signed-off-by: NWu Fengguang <wfg@linux.intel.com>
Acked-by: NEric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: NDuane Griffin <duaneg@dghda.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

While testing a kernel with memory poisoning enabled, I saw some warnings
about the redzone getting clobbered when chasing DFS referrals. The
buffer allocation for the unicode converted version of the searchName is
too small and needs to take null termination into account.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Acked-by: NSteve French <sfrench@us.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Define the OCFS2_FEATURE_COMPAT_JBD2 bit in the filesystem header.
Signed-off-by: NJoel Becker <joel.becker@oracle.com>
Signed-off-by: NMark Fasheh <mfasheh@suse.com>

When we create xattr bucket during the process of xattr set, we always
need to update the ocfs2_xattr_search since even if the bucket size is
the same as block size, the offset will change because of the removal
of the ocfs2_xattr_block header.
Signed-off-by: NTao Ma <tao.ma@oracle.com>
Signed-off-by: NMark Fasheh <mfasheh@suse.com>

Preserve any error returned by the bio layer.
Reviewed-by: NEric Sandeen <sandeen@sandeen.net>
Reviewed-by: NTim Shimmin <tes@sgi.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Instead of implementing our own checks use inode_change_ok to check for
necessary permission in setattr.  There is a slight change in behaviour
as inode_change_ok doesn't allow i_mode updates to add the suid or sgid
without superuser privilegues while the old XFS code just stripped away
those bits from the file mode.

(First sent on Semptember 29th)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

XFS has a mode called invisble I/O that doesn't update any of the
timestamps.  It's used for HSM-style applications and exposed through
the nasty open by handle ioctl.

Instead of doing directly assignment of file operations that set an
internal flag for it add a new FMODE_NOCMTIME flag that we can check
in the normal file operations.

(addition of the generic VFS flag has been ACKed by Al as an interims
 solution)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

 - xfs_sb.h add the XFS_SB_VERSION2_PARENTBIT features2 that has been
   around in userspace for some time
 - xfs_inode.h: move a few things out of __KERNEL__ that are needed by
   userspace
 - xfs_mount.h: only include xfs_sync.h under __KERNEL__
 - xfs_inode.c: minor whitespace fixup.  I accidentaly changes this when
   importing this file for use by userspace.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Check for the project ID after attaching all inodes to the transaction.
That way the unlock in the error case is done by the transaction subsystem,
which guaratees that is uses the right flags (which was wrong from day one
of this check), and avoids having special code unlocking an array of inodes
with potential duplicates.  Attaching the inode first is the method used
by xfs_rename and the other namespace methods all other error that require
multiple locked inodes.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <david@fromorbit.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Replace the b_fspriv pointer and it's ugly accessors with a properly types
xfs_mount pointer.  Also switch log reocvery over to it instead of using
b_fspriv for the mount pointer.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <david@fromorbit.com>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Miles Lane tailing /sys files hit a BUG which Pekka Enberg has tracked
to my 966c8c12 sprint_symbol(): use
less stack exposing a bug in slub's list_locations() -
kallsyms_lookup() writes a 0 to namebuf[KSYM_NAME_LEN-1], but that was
beyond the end of page provided.

The 100 slop which list_locations() allows at end of page looks roughly
enough for all the other stuff it might print after the symbol before
it checks again: break out KSYM_SYMBOL_LEN earlier than before.

Latencytop and ftrace and are using KSYM_NAME_LEN buffers where they
need KSYM_SYMBOL_LEN buffers, and vmallocinfo a 2*KSYM_NAME_LEN buffer
where it wants a KSYM_SYMBOL_LEN buffer: fix those before anyone copies
them.

[akpm@linux-foundation.org: ftrace.h needs module.h]
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc Miles Lane <miles.lane@gmail.com>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NSteven Rostedt <srostedt@redhat.com>
Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On umount two event will be dispatched to watcher:

1: inotify_dev_queue_event(.., IN_UNMOUNT,..)
2: remove_watch(watch, dev)
    ->inotify_dev_queue_event(.., IN_IGNORED, ..)

But if watcher has IN_ONESHOT bit set then the watcher will be released
inside first event.  Which result in accessing invalid object later.  IMHO
it is not pure regression.  This bug wasn't triggered while initial
inotify interface testing phase because of another bug in IN_ONESHOT
handling logic :)

  commit ac74c00e
  Author: Ulisses Furquim <ulissesf@gmail.com>
  Date:   Fri Feb 8 04:18:16 2008 -0800
    inotify: fix check for one-shot watches before destroying them
    As the IN_ONESHOT bit is never set when an event is sent we must check it
    in the watch's mask and not in the event's mask.

TESTCASE:
mkdir mnt
mount -ttmpfs none mnt
mkdir mnt/d
./inotify mnt/d&
umount mnt ## << lockup or crash here

TESTSOURCE:
/* gcc -oinotify inotify.c */
#include <stdio.h>
#include <stdlib.h>
#include <sys/inotify.h>

int main(int argc, char **argv)
{
        char buf[1024];
        struct inotify_event *ie;
        char *p;
        int i;
        ssize_t l;

        p = argv[1];
        i = inotify_init();
        inotify_add_watch(i, p, ~0);

        l = read(i, buf, sizeof(buf));
        printf("read %d bytes\n", l);
        ie = (struct inotify_event *) buf;
        printf("event mask: %d\n", ie->mask);
	return 0;
}
Signed-off-by: NDmitri Monakhov <dmonakhov@openvz.org>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Robert Love <rlove@google.com>
Cc: Ulisses Furquim <ulissesf@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The large pages fix from bcf8039e broke 32-bit pagemap by pulling the
pagemap entry code out into a function with the wrong return type.
Pagemap entries are 64 bits on all systems and unsigned long is only 32
bits on 32-bit systems.
Signed-off-by: NMatt Mackall <mpm@selenic.com>
Reported-by: NDoug Graham <dgraham@nortel.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: <stable@kernel.org>		[2.6.26.x, 2.6.27.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Revert

    commit e8ced39d
    Author: Mingming Cao <cmm@us.ibm.com>
    Date:   Fri Jul 11 19:27:31 2008 -0400

        percpu_counter: new function percpu_counter_sum_and_set

As described in

	revert "percpu counter: clean up percpu_counter_sum_and_set()"

the new percpu_counter_sum_and_set() is racy against updates to the
cpu-local accumulators on other CPUs.  Revert that change.

This means that ext4 will be slow again.  But correct.
Reported-by: NEric Dumazet <dada1@cosmosbay.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: <linux-ext4@vger.kernel.org>
Cc: <stable@kernel.org>		[2.6.27.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Revert

    commit 1f7c14c6
    Author: Mingming Cao <cmm@us.ibm.com>
    Date:   Thu Oct 9 12:50:59 2008 -0400

        percpu counter: clean up percpu_counter_sum_and_set()

Before this patch we had the following:

percpu_counter_sum(): return the percpu_counter's value

percpu_counter_sum_and_set(): return the percpu_counter's value, copying
that value into the central value and zeroing the per-cpu counters before
returning.

After this patch, percpu_counter_sum_and_set() has gone, and
percpu_counter_sum() gets the old percpu_counter_sum_and_set()
functionality.

Problem is, as Eric points out, the old percpu_counter_sum_and_set()
functionality was racy and wrong.  It zeroes out counters on "other" cpus,
without holding any locks which will prevent races agaist updates from
those other CPUS.

This patch reverts 1f7c14c6.  This means
that percpu_counter_sum_and_set() still has the race, but
percpu_counter_sum() does not.

Note that this is not a simple revert - ext4 has since started using
percpu_counter_sum() for its dirty_blocks counter as well.

Note that this revert patch changes percpu_counter_sum() semantics.

Before the patch, a call to percpu_counter_sum() will bring the counter's
central counter mostly up-to-date, so a following percpu_counter_read()
will return a close value.

After this patch, a call to percpu_counter_sum() will leave the counter's
central accumulator unaltered, so a subsequent call to
percpu_counter_read() can now return a significantly inaccurate result.

If there is any code in the tree which was introduced after
e8ced39d was merged, and which depends
upon the new percpu_counter_sum() semantics, that code will break.
Reported-by: NEric Dumazet <dada1@cosmosbay.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The patch 6341c393 "tracehook: exec" introduced a small regression in
2.6.27 regarding binfmt_misc exec event reporting.  Since the reporting
is now done in the common search_binary_handler() function, an exec
of a misc binary will result in two (or possibly multiple) exec events
being reported, instead of just a single one, because the misc handler
contains a recursive call to search_binary_handler.

To add to the confusion, if PTRACE_O_TRACEEXEC is not active, the multiple
SIGTRAP signals will in fact cause only a single ptrace intercept, as the
signals are not queued.  However, if PTRACE_O_TRACEEXEC is on, the debugger
will actually see multiple ptrace intercepts (PTRACE_EVENT_EXEC).

The test program included below demonstrates the problem.

This change fixes the bug by calling tracehook_report_exec() only in the
outermost search_binary_handler() call (bprm->recursion_depth == 0).

The additional change to restore bprm->recursion_depth after each binfmt
load_binary call is actually superfluous for this bug, since we test the
value saved on entry to search_binary_handler().  But it keeps the use of
of the depth count to its most obvious expected meaning.  Depending on what
binfmt handlers do in certain cases, there could have been false-positive
tests for recursion limits before this change.

    /* Test program using PTRACE_O_TRACEEXEC.
       This forks and exec's the first argument with the rest of the arguments,
       while ptrace'ing.  It expects to see one PTRACE_EVENT_EXEC stop and
       then a successful exit, with no other signals or events in between.

       Test for kernel doing two PTRACE_EVENT_EXEC stops for a binfmt_misc exec:

       $ gcc -g traceexec.c -o traceexec
       $ sudo sh -c 'echo :test:M::foobar::/bin/cat: > /proc/sys/fs/binfmt_misc/register'
       $ echo 'foobar test' > ./foobar
       $ chmod +x ./foobar
       $ ./traceexec ./foobar; echo $?
       ==> good <==
       foobar test
       0
       $
       ==> bad <==
       foobar test
       unexpected status 0x4057f != 0
       3
       $

    */

    #include <stdio.h>
    #include <sys/types.h>
    #include <sys/wait.h>
    #include <sys/ptrace.h>
    #include <unistd.h>
    #include <signal.h>
    #include <stdlib.h>

    static void
    wait_for (pid_t child, int expect)
    {
      int status;
      pid_t p = wait (&status);
      if (p != child)
	{
	  perror ("wait");
	  exit (2);
	}
      if (status != expect)
	{
	  fprintf (stderr, "unexpected status %#x != %#x\n", status, expect);
	  exit (3);
	}
    }

    int
    main (int argc, char **argv)
    {
      pid_t child = fork ();

      if (child < 0)
	{
	  perror ("fork");
	  return 127;
	}
      else if (child == 0)
	{
	  ptrace (PTRACE_TRACEME);
	  raise (SIGUSR1);
	  execv (argv[1], &argv[1]);
	  perror ("execve");
	  _exit (127);
	}

      wait_for (child, W_STOPCODE (SIGUSR1));

      if (ptrace (PTRACE_SETOPTIONS, child,
		  0L, (void *) (long) PTRACE_O_TRACEEXEC) != 0)
	{
	  perror ("PTRACE_SETOPTIONS");
	  return 4;
	}

      if (ptrace (PTRACE_CONT, child, 0L, 0L) != 0)
	{
	  perror ("PTRACE_CONT");
	  return 5;
	}

      wait_for (child, W_STOPCODE (SIGTRAP | (PTRACE_EVENT_EXEC << 8)));

      if (ptrace (PTRACE_CONT, child, 0L, 0L) != 0)
	{
	  perror ("PTRACE_CONT");
	  return 6;
	}

      wait_for (child, W_EXITCODE (0, 0));

      return 0;
    }
Reported-by: NArnd Bergmann <arnd@arndb.de>
CC: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Signed-off-by: NRoland McGrath <roland@redhat.com>

None of this code appears to be used anywhere so remove it.
Reviewed-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

While 44003728 "[PATCH] switch all filesystems over to
d_obtain_alias" removed some cases where fh_to_dentry() and
fh_to_parent() could return NULL, there are still a few NULL returns
left in individual filesystems.  Thus it was a mistake for that commit
to remove the handling of NULL returns in the callers.

Revert those parts of 44003728 which removed the NULL handling.

(We could, alternatively, modify all implementations to return -ESTALE
instead of NULL, but that proves to require fixing a number of
filesystems, and in some cases it's arguably more natural to return
NULL.)

Thanks to David for original patch and Linus, Christoph, and Hugh for
review.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Cc: David Howells <dhowells@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Changeset a238b790 (Call fasync()
functions without the BKL) introduced a race which could leave
file->f_flags in a state inconsistent with what the underlying
driver/filesystem believes.  Revert that change, and also fix the same
races in ioctl_fioasync() and ioctl_fionbio().

This is a minimal, short-term fix; the real fix will not involve the
BKL.
Reported-by: NOleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: NJonathan Corbet <corbet@lwn.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When project quota is active and is being used for directory tree
quota control, we disallow rename outside the current directory
tree. This requires a check to be made after all the inodes
involved in the rename are locked. We fail to unlock the inodes
correctly if we disallow the rename when the target is outside the
current directory tree. This results in a hang on the next access
to the inodes involved in failed rename.
Reported-by: NArkadiusz Miskiewicz <arekm@maven.pl>
Signed-off-by: NDave Chinner <david@fromorbit.com>
Tested-by: NArkadiusz Miskiewicz <arekm@maven.pl>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Hit this assert because an inode was tagged with XFS_ICI_RECLAIM_TAG but
not XFS_IRECLAIMABLE|XFS_IRECLAIM.  This is because xfs_iget_cache_hit()
first clears XFS_IRECLAIMABLE and then calls __xfs_inode_clear_reclaim_tag()
while only holding the pag_ici_lock in read mode so we can race with
xfs_reclaim_inodes_ag().  Looks like xfs_reclaim_inodes_ag() will do the
right thing anyway so just remove the assert.

Thanks to Christoph for pointing out where the problem was.
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
Reviewed-by: NChristoph Hellwig <hch@infradead.org>

entries_size is probably left over from when we used to pass the
size to kmem_free().
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
Reviewed-by: NChristoph Hellwig <hch@infradead.org>
Reviewed-by: NEric Sandeen <sandeen@sandeen.net>

We check the return value of all other calls to xfs_buf_get_noaddr().
Make sense to do it here too.
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>
Reviewed-by: NChristoph Hellwig <hch@infradead.org>
Reviewed-by: NEric Sandeen <sandeen@sandeen.net>

When project quota is active and is being used for directory tree
quota control, we disallow rename outside the current directory
tree. This requires a check to be made after all the inodes
involved in the rename are locked. We fail to unlock the inodes
correctly if we disallow the rename when the target is outside the
current directory tree. This results in a hang on the next access
to the inodes involved in failed rename.
Reported-by: NArkadiusz Miskiewicz <arekm@maven.pl>
Signed-off-by: NDave Chinner <david@fromorbit.com>
Tested-by: NArkadiusz Miskiewicz <arekm@maven.pl>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NLachlan McIlroy <lachlan@sgi.com>

Update FMODE_NDELAY before each ioctl call so that we can kill the
magic FMODE_NDELAY_NOW.  It would be even better to do this directly
in setfl(), but for that we'd need to have FMODE_NDELAY for all files,
not just block special files.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The way the bd_claim for the FMODE_EXCL case is implemented is rather
confusing.  Clean it up to the most logical style.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Move the inode tracing into xfs_iget.c / xfs_inode.h and kill xfs_vnode.c
now that it's empty.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <david@fromorbit.com>
Signed-off-by: NNiv Sardi <xaiki@sgi.com>

The whole machinery to wait on I/O completion is related to the I/O path
and should be there instead of in xfs_vnode.c.  Also give the functions
more descriptive names.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <david@fromorbit.com>
Signed-off-by: NNiv Sardi <xaiki@sgi.com>

There's just one caller of this helper, and it's much cleaner to just merge
the xfs_do_force_shutdown call into it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <david@fromorbit.com>
Signed-off-by: NNiv Sardi <xaiki@sgi.com>

There's almost nothing left in this function, instead remove the IRELE
on the real times inodes and the call to XFS_QM_UNMOUNT into xfs_unmountfs.

For the regular unmount case that means it now also happenes after dmapi
notification, but otherwise there is no difference in behaviour.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <david@fromorbit.com>
Signed-off-by: NNiv Sardi <xaiki@sgi.com>

Currently we explicitly call xfs_iflush on the quota, real-time and root
inodes from xfs_unmount_flush.  But we just called xfs_sync_inodes with
SYNC_ATTR and do an XFS_bflush aka xfs_flush_buftarg to make sure all inodes
are on disk already, so there is no need for these special cases.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <david@fromorbit.com>
Signed-off-by: NNiv Sardi <xaiki@sgi.com>

Use xfs_trans_ijoin in xfs_trans_iget in case we need to join an inode into
a transaction instead of opencoding it.  Based on a discussion with and an
incomplete patch from Niv Sardi.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <david@fromorbit.com>
Signed-off-by: NNiv Sardi <xaiki@sgi.com>

We never supported shared read-only filesystems, so remove the dead
code left over from IRIX for it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <david@fromorbit.com>
Signed-off-by: NNiv Sardi <xaiki@sgi.com>