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  1. 01 9月, 2017 1 次提交
  3. 30 6月, 2017 2 次提交
  5. 28 5月, 2017 1 次提交
  7. 26 4月, 2017 1 次提交
    • N
      NFS: don't try to cross a mountpount when there isn't one there. · 99bbf6ec
      由 NeilBrown 提交于 
      consider the sequence of commands:
 mkdir -p /import/nfs /import/bind /import/etc
 mount --bind / /import/bind
 mount --make-private /import/bind
 mount --bind /import/etc /import/bind/etc

 exportfs -o rw,no_root_squash,crossmnt,async,no_subtree_check localhost:/
 mount -o vers=4 localhost:/ /import/nfs
 ls -l /import/nfs/etc

You would not expect this to report a stale file handle.
Yet it does.

The manipulations under /import/bind cause the dentry for
/etc to get the DCACHE_MOUNTED flag set, even though nothing
is mounted on /etc.  This causes nfsd to call
nfsd_cross_mnt() even though there is no mountpoint.  So an
upcall to mountd for "/etc" is performed.

The 'crossmnt' flag on the export of / causes mountd to
report that /etc is exported as it is a descendant of /.  It
assumes the kernel wouldn't ask about something that wasn't
a mountpoint.  The filehandle returned identifies the
filesystem and the inode number of /etc.

When this filehandle is presented to rpc.mountd, via
"nfsd.fh", the inode cannot be found associated with any
name in /etc/exports, or with any mountpoint listed by
getmntent().  So rpc.mountd says the filehandle doesn't
exist. Hence ESTALE.

This is fixed by teaching nfsd not to trust DCACHE_MOUNTED
too much.  It is just a hint, not a guarantee.
Change nfsd_mountpoint() to return '1' for a certain mountpoint,
'2' for a possible mountpoint, and 0 otherwise.

Then change nfsd_crossmnt() to check if follow_down()
actually found a mountpount and, if not, to avoid performing
a lookup if the location is not known to certainly require
an export-point.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
      99bbf6ec
  9. 11 4月, 2017 1 次提交
    • N
      sched/core: Remove 'task' parameter and rename tsk_restore_flags() to current_restore_flags() · 717a94b5
      由 NeilBrown 提交于 
      It is not safe for one thread to modify the ->flags
of another thread as there is no locking that can protect
the update.

So tsk_restore_flags(), which takes a task pointer and modifies
the flags, is an invitation to do the wrong thing.

All current users pass "current" as the task, so no developers have
accepted that invitation.  It would be best to ensure it remains
that way.

So rename tsk_restore_flags() to current_restore_flags() and don't
pass in a task_struct pointer.  Always operate on current->flags.
Signed-off-by: NNeilBrown <neilb@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      717a94b5
  11. 21 2月, 2017 2 次提交
    • C
      nfsd: special case truncates some more · 783112f7
      由 Christoph Hellwig 提交于 
      Both the NFS protocols and the Linux VFS use a setattr operation with a
bitmap of attributes to set to set various file attributes including the
file size and the uid/gid.

The Linux syscalls never mix size updates with unrelated updates like
the uid/gid, and some file systems like XFS and GFS2 rely on the fact
that truncates don't update random other attributes, and many other file
systems handle the case but do not update the other attributes in the
same transaction.  NFSD on the other hand passes the attributes it gets
on the wire more or less directly through to the VFS, leading to updates
the file systems don't expect.  XFS at least has an assert on the
allowed attributes, which caught an unusual NFS client setting the size
and group at the same time.

To handle this issue properly this splits the notify_change call in
nfsd_setattr into two separate ones.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Tested-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
      783112f7
    • C
      nfsd: minor nfsd_setattr cleanup · 758e99fe
      由 Christoph Hellwig 提交于 
      Simplify exit paths, size_change use.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: stable@kernel.org
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
      758e99fe
  13. 10 2月, 2017 1 次提交
  15. 01 2月, 2017 4 次提交
  17. 25 12月, 2016 1 次提交
  19. 16 12月, 2016 1 次提交
  21. 09 12月, 2016 1 次提交
  23. 08 10月, 2016 1 次提交
  25. 11 8月, 2016 1 次提交
  27. 05 8月, 2016 8 次提交
  29. 02 5月, 2016 1 次提交
  31. 05 3月, 2016 1 次提交
  33. 23 1月, 2016 1 次提交
    • A
      wrappers for ->i_mutex access · 5955102c
      由 Al Viro 提交于 
      parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      5955102c
  35. 15 1月, 2016 1 次提交
  37. 09 1月, 2016 1 次提交
    • N
      nfsd: don't hold i_mutex over userspace upcalls · bbddca8e
      由 NeilBrown 提交于 
      We need information about exports when crossing mountpoints during
lookup or NFSv4 readdir.  If we don't already have that information
cached, we may have to ask (and wait for) rpc.mountd.

In both cases we currently hold the i_mutex on the parent of the
directory we're asking rpc.mountd about.  We've seen situations where
rpc.mountd performs some operation on that directory that tries to take
the i_mutex again, resulting in deadlock.

With some care, we may be able to avoid that in rpc.mountd.  But it
seems better just to avoid holding a mutex while waiting on userspace.

It appears that lookup_one_len is pretty much the only operation that
needs the i_mutex.  So we could just drop the i_mutex elsewhere and do
something like

	mutex_lock()
	lookup_one_len()
	mutex_unlock()

In many cases though the lookup would have been cached and not required
the i_mutex, so it's more efficient to create a lookup_one_len() variant
that only takes the i_mutex when necessary.
Signed-off-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      bbddca8e
  39. 08 12月, 2015 1 次提交
  41. 13 10月, 2015 1 次提交
  43. 01 9月, 2015 1 次提交
  45. 23 6月, 2015 1 次提交
    • C
      nfsd: take struct file setup fully into nfs4_preprocess_stateid_op · af90f707
      由 Christoph Hellwig 提交于 
      This patch changes nfs4_preprocess_stateid_op so it always returns
a valid struct file if it has been asked for that.  For that we
now allocate a temporary struct file for special stateids, and check
permissions if we got the file structure from the stateid.  This
ensures that all callers will get their handling of special stateids
right, and avoids code duplication.

There is a little wart in here because the read code needs to know
if we allocated a file structure so that it can copy around the
read-ahead parameters.  In the long run we should probably aim to
cache full file structures used with special stateids instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
      af90f707
  47. 20 6月, 2015 1 次提交
  49. 29 5月, 2015 1 次提交
  51. 05 5月, 2015 1 次提交
  53. 16 4月, 2015 1 次提交
  55. 23 2月, 2015 1 次提交
    • D
      VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry) · e36cb0b8
      由 David Howells 提交于 
      Convert the following where appropriate:

 (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry).

 (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry).

 (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry).  This is actually more
     complicated than it appears as some calls should be converted to
     d_can_lookup() instead.  The difference is whether the directory in
     question is a real dir with a ->lookup op or whether it's a fake dir with
     a ->d_automount op.

In some circumstances, we can subsume checks for dentry->d_inode not being
NULL into this, provided we the code isn't in a filesystem that expects
d_inode to be NULL if the dirent really *is* negative (ie. if we're going to
use d_inode() rather than d_backing_inode() to get the inode pointer).

Note that the dentry type field may be set to something other than
DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS
manages the fall-through from a negative dentry to a lower layer.  In such a
case, the dentry type of the negative union dentry is set to the same as the
type of the lower dentry.

However, if you know d_inode is not NULL at the call site, then you can use
the d_is_xxx() functions even in a filesystem.

There is one further complication: a 0,0 chardev dentry may be labelled
DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE.  Strictly, this was
intended for special directory entry types that don't have attached inodes.

The following perl+coccinelle script was used:

use strict;

my @callers;
open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') ||
    die "Can't grep for S_ISDIR and co. callers";
@callers = <$fd>;
close($fd);
unless (@callers) {
    print "No matches\n";
    exit(0);
}

my @cocci = (
    '@@',
    'expression E;',
    '@@',
    '',
    '- S_ISLNK(E->d_inode->i_mode)',
    '+ d_is_symlink(E)',
    '',
    '@@',
    'expression E;',
    '@@',
    '',
    '- S_ISDIR(E->d_inode->i_mode)',
    '+ d_is_dir(E)',
    '',
    '@@',
    'expression E;',
    '@@',
    '',
    '- S_ISREG(E->d_inode->i_mode)',
    '+ d_is_reg(E)' );

my $coccifile = "tmp.sp.cocci";
open($fd, ">$coccifile") || die $coccifile;
print($fd "$_\n") || die $coccifile foreach (@cocci);
close($fd);

foreach my $file (@callers) {
    chomp $file;
    print "Processing ", $file, "\n";
    system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 ||
	die "spatch failed";
}

[AV: overlayfs parts skipped]
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      e36cb0b8