litmus-rt.git/fs/cachefiles, branch test

VFS: fs/cachefiles: d_backing_inode() annotations

2015-04-15T19:06:59+00:00

Signed-off-by: David Howells 
Signed-off-by: Al Viro

VFS: Cachefiles should perform fs modifications on the top layer only

2015-04-15T19:06:54+00:00

Cachefiles should perform fs modifications (eg. vfs_unlink()) on the top layer
only and should not attempt to alter the lower layer.

Signed-off-by: David Howells 
Signed-off-by: Al Viro

Cachefiles: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversions

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

Fix up the following scripted S_ISDIR/S_ISREG/S_ISLNK conversions (or lack
thereof) in cachefiles:

 (1) Cachefiles mostly wants to use d_can_lookup() rather than d_is_dir() as
     it doesn't want to deal with automounts in its cache.

 (2) Coccinelle didn't find S_IS* expressions in ASSERT() statements in
     cachefiles.

Signed-off-by: David Howells 
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

assorted conversions to %p[dD]

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

Signed-off-by: Al Viro

Merge tag 'fscache-fixes-20141013' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

2014-10-14T06:40:15+00:00

Pull fs-cache fixes from David Howells:
 "Two fixes for bugs in CacheFiles and a cleanup in FS-Cache"

* tag 'fscache-fixes-20141013' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  fs/fscache/object-list.c: use __seq_open_private()
  CacheFiles: Fix incorrect test for in-memory object collision
  CacheFiles: Handle object being killed before being set up

CacheFiles: Fix incorrect test for in-memory object collision

2014-10-13T16:52:21+00:00

When CacheFiles cache objects are in use, they have in-memory representations,
as defined by the cachefiles_object struct.  These are kept in a tree rooted in
the cache and indexed by dentry pointer (since there's a unique mapping between
object index key and dentry).

Collisions can occur between a representation already in the tree and a new
representation being set up because it takes time to dispose of an old
representation - particularly if it must be unlinked or renamed.

When such a collision occurs, cachefiles_mark_object_active() is meant to check
to see if the old, already-present representation is in the process of being
discarded (ie. FSCACHE_OBJECT_IS_LIVE is not set on it) - and, if so, wait for
the representation to be removed (ie. CACHEFILES_OBJECT_ACTIVE is then
cleared).

However, the test for whether the old representation is still live is checking
the new object - which always will be live at this point.  This leads to an
oops looking like:

	CacheFiles: Error: Unexpected object collision
	object: OBJ1b354
	objstate=LOOK_UP_OBJECT fl=8 wbusy=2 ev=0[0]
	ops=0 inp=0 exc=0
	parent=ffff88053f5417c0
	cookie=ffff880538f202a0 [pr=ffff8805381b7160 nd=ffff880509c6eb78 fl=27]
	key=[8] '2490000000000000'
	xobject: OBJ1a600
	xobjstate=DROP_OBJECT fl=70 wbusy=2 ev=0[0]
	xops=0 inp=0 exc=0
	xparent=ffff88053f5417c0
	xcookie=ffff88050f4cbf70 [pr=ffff8805381b7160 nd=          (null) fl=12]
	------------[ cut here ]------------
	kernel BUG at fs/cachefiles/namei.c:200!
	...
	Workqueue: fscache_object fscache_object_work_func [fscache]
	...
	RIP: ... cachefiles_walk_to_object+0x7ea/0x860 [cachefiles]
	...
	Call Trace:
	 [] ? cachefiles_lookup_object+0x58/0x100 [cachefiles]
	 [] ? fscache_look_up_object+0xb9/0x1d0 [fscache]
	 [] ? fscache_parent_ready+0x2d/0x80 [fscache]
	 [] ? fscache_object_work_func+0x92/0x1f0 [fscache]
	 [] ? process_one_work+0x16b/0x400
	 [] ? worker_thread+0x116/0x380
	 [] ? manage_workers.isra.21+0x290/0x290
	 [] ? kthread+0xbc/0xe0
	 [] ? flush_kthread_worker+0x80/0x80
	 [] ? ret_from_fork+0x7c/0xb0
	 [] ? flush_kthread_worker+0x80/0x80

Reported-by: Manuel Schölling 
Signed-off-by: David Howells 
Acked-by: Steve Dickson

cachefiles_write_page(): switch to __kernel_write()

2014-10-09T06:39:05+00:00

Signed-off-by: Al Viro

CacheFiles: Handle object being killed before being set up

2014-09-30T13:50:28+00:00

If a cache object gets killed whilst in the process of being set up - for
instance if the netfs relinquishes the cookie that the object is associated
with - then the object's state machine will transit to the DROP_OBJECT state
without necessarily going through the LOOKUP_OBJECT or CREATE_OBJECT states.

This is a problem for CacheFiles because cachefiles_drop_object() assumes that
object->dentry will be set upon reaching the DROP_OBJECT state and has an
ASSERT() to that effect (see the oops below) - but object->dentry doesn't get
set until the LOOKUP_OBJECT or CREATE_OBJECT states (and not always then if
they fail).

To fix this, just make the dentry cleanup in cachefiles_drop_object()
conditional on the dentry actually being set and remove the assertion.

	CacheFiles: Assertion failed
	------------[ cut here ]------------
	kernel BUG at .../fs/cachefiles/namei.c:425!
	...
	Workqueue: fscache_object fscache_object_work_func [fscache]
	...
	RIP: ... cachefiles_delete_object+0xcd/0x110 [cachefiles]
	...
	Call Trace:
	 [] ? cachefiles_drop_object+0xff/0x130 [cachefiles]
	 [] ? fscache_drop_object+0xd1/0x1d0 [fscache]
	 [] ? fscache_object_work_func+0x87/0x210 [fscache]
	 [] ? process_one_work+0x155/0x450
	 [] ? worker_thread+0x114/0x370
	 [] ? manage_workers.isra.21+0x2c0/0x2c0
	 [] ? kthread+0xbc/0xe0
	 [] ? flush_kthread_worker+0xa0/0xa0
	 [] ? ret_from_fork+0x7c/0xb0
	 [] ? flush_kthread_worker+0xa0/0xa0

Reported-by: Manuel Schölling 
Signed-off-by: David Howells 
Acked-by: Steve Dickson

fs/cachefiles: add missing \n to kerror conversions

2014-09-26T15:10:35+00:00

Commit 0227d6abb378 ("fs/cachefiles: replace kerror by pr_err") didn't
include newline featuring in original kerror definition

Signed-off-by: Fabian Frederick 
Reported-by: David Howells 
Acked-by: David Howells 
Cc: 	[3.16.x]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds