linux-toradex.git/fs/autofs4, branch v4.0.9

autofs4 copy_dev_ioctl(): keep the value of ->size we'd used for allocation

2015-02-22T16:43:34+00:00

X-Coverup: just ask spender
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro

VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry)

2015-02-22T16:38:41+00:00

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: David Howells 
Signed-off-by: Al Viro

autofs4: Wrong format for printing dentry

2015-02-20T09:56:45+00:00

%pD for struct file*, %pd for struct dentry*.

Fixes: a455589f181e ("assorted conversions to %p[dD]")
Signed-off-by: Rasmus Villemoes 
Signed-off-by: Al Viro

assorted conversions to %p[dD]

2014-11-19T18:01:20+00:00

Signed-off-by: Al Viro

move d_rcu from overlapping d_child to overlapping d_alias

2014-11-03T20:20:29+00:00

Signed-off-by: Al Viro

autofs4: d_manage() should return -EISDIR when appropriate in rcu-walk mode.

2014-10-14T00:18:16+00:00

If rcu-walk mode we don't *have* to return -EISDIR for non-mount-traps
as we will simply drop into REF-walk and handling DCACHE_NEED_AUTOMOUNT
dentrys the slow way.  But it is better if we do when possible.

In 'oz_mode', use the same condition as ref-walk: if not a mountpoint,
then it must be -EISDIR.

In regular mode there are most tests needed.  Most of them can be
performed without taking any spinlocks.  If we find a directory that
isn't obviously empty, and isn't mounted on, we need to call
'simple_empty()' which does take a spinlock.  If this turned out to hurt
performance, some other approach could be found to signal when a
directory is known to be empty.

Signed-off-by: NeilBrown 
Reviewed-by: Ian Kent 
Tested-by: Ian Kent 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

autofs4: avoid taking fs_lock during rcu-walk

2014-10-14T00:18:16+00:00

->fs_lock protects AUTOFS_INF_EXPIRING.  We need to be sure that once
the flag is set, no new references beneath the dentry are taken.  So
rcu-walk currently needs to take fs_lock before checking the flag.  This
hurts performance.

Change the expiry to a two-stage process.  First set AUTOFS_INF_NO_RCU
which forces any path walk into ref-walk mode, then drop the lock and
call synchronize_rcu().  Once that returns we can be sure no rcu-walk is
active beneath the dentry and we can check reference counts again.

Now during an RCU-walk we can test AUTOFS_INF_EXPIRING without taking
the lock as along as we test AUTOFS_INF_NO_RCU too.  If either are set,
we must abort the RCU-walk If neither are set, we know that refcounts
will be tested again after we finish the RCU-walk so we are safe to
continue.

->fs_lock is still taken in d_manage() to check for a non-trap
directory.  That will be resolved in the next patch.

Signed-off-by: NeilBrown 
Reviewed-by: Ian Kent 
Tested-by: Ian Kent 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

autofs4: make "autofs4_can_expire" idempotent.

2014-10-14T00:18:16+00:00

Have a "test" function change the value it is testing can be confusing,
particularly as a future patch will be calling this function twice.

So move the update for 'last_used' to avoid repeat expiry to the place
where the final determination on what to expire is known.

Signed-off-by: NeilBrown 
Reviewed-by: Ian Kent 
Tested-by: Ian Kent 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

autofs4: factor should_expire() out of autofs4_expire_indirect.

2014-10-14T00:18:16+00:00

Future patch will potentially call this twice, so make it separate.

Signed-off-by: NeilBrown 
Reviewed-by: Ian Kent 
Tested-by: Ian Kent 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

autofs4: allow RCU-walk to walk through autofs4

2014-10-14T00:18:16+00:00

This series teaches autofs about RCU-walk so that we don't drop straight
into REF-walk when we hit an autofs directory, and so that we avoid
spinlocks as much as possible when performing an RCU-walk.

This is needed so that the benefits of the recent NFS support for
RCU-walk are fully available when NFS filesystems are automounted.

Patches have been carefully reviewed and tested both with test suites
and in production - thanks a lot to Ian Kent for his support there.

This patch (of 6):

Any attempt to look up a pathname that passes though an autofs4 mount is
currently forced out of RCU-walk into REF-walk.

This can significantly hurt performance of many-thread work loads on
many-core systems, especially if the automounted filesystem supports
RCU-walk but doesn't get to benefit from it.

So if autofs4_d_manage is called with rcu_walk set, only fail with -ECHILD
if it is necessary to wait longer than a spinlock.

Signed-off-by: NeilBrown 
Reviewed-by: Ian Kent 
Tested-by: Ian Kent 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds