linux-toradex.git/fs/cachefiles, branch v2.6.33.5

CacheFiles: Fix error handling in cachefiles_determine_cache_security()

2010-05-26T21:32:11+00:00

commit 7ac512aa8237c43331ffaf77a4fd8b8d684819ba upstream.

cachefiles_determine_cache_security() is expected to return with a
security override in place.  However, if set_create_files_as() fails, we
fail to do this.  In this case, we should just reinstate the security
override that was set by the caller.

Furthermore, if set_create_files_as() fails, we should dispose of the
new credentials we were in the process of creating.

Signed-off-by: David Howells 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

CacheFiles: Fix a race in cachefiles_delete_object() vs rename

2010-02-20T15:06:35+00:00

cachefiles_delete_object() can race with rename.  It gets the parent directory
of the object it's asked to delete, then locks it - but rename may have changed
the object's parent between the get and the completion of the lock.

However, if such a circumstance is detected, we abandon our attempt to delete
the object - since it's no longer in the index key path, it won't be seen
again by lookups of that key.  The assumption is that cachefilesd may have
culled it by renaming it to the graveyard for later destruction.

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

Untangling ima mess, part 2: deal with counters

2009-12-16T17:16:47+00:00

* do ima_get_count() in __dentry_open()
* stop doing that in followups
* move ima_path_check() to right after nameidata_to_filp()
* don't bump counters on it

Signed-off-by: Al Viro

switch cachefiles to kern_path()

2009-12-16T17:16:44+00:00

Signed-off-by: Al Viro

tree-wide: convert open calls to remove spaces to skip_spaces() lib function

2009-12-15T16:53:32+00:00

Makes use of skip_spaces() defined in lib/string.c for removing leading
spaces from strings all over the tree.

It decreases lib.a code size by 47 bytes and reuses the function tree-wide:
   text    data     bss     dec     hex filename
  64688     584     592   65864   10148 (TOTALS-BEFORE)
  64641     584     592   65817   10119 (TOTALS-AFTER)

Also, while at it, if we see (*str && isspace(*str)), we can be sure to
remove the first condition (*str) as the second one (isspace(*str)) also
evaluates to 0 whenever *str == 0, making it redundant. In other words,
"a char equals zero is never a space".

Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below,
and found occurrences of this pattern on 3 more files:
    drivers/leds/led-class.c
    drivers/leds/ledtrig-timer.c
    drivers/video/output.c

@@
expression str;
@@

( // ignore skip_spaces cases
while (*str &&  isspace(*str)) { \(str++;\|++str;\) }
|
- *str &&
isspace(*str)
)

Signed-off-by: André Goddard Rosa 
Cc: Julia Lawall 
Cc: Martin Schwidefsky 
Cc: Jeff Dike 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Cc: Richard Purdie 
Cc: Neil Brown 
Cc: Kyle McMartin 
Cc: Henrique de Moraes Holschuh 
Cc: David Howells 
Cc: 
Cc: Samuel Ortiz 
Cc: Patrick McHardy 
Cc: Takashi Iwai 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

CacheFiles: Update IMA counters when using dentry_open

2009-12-01T15:35:11+00:00

When IMA is active, using dentry_open without updating the
IMA counters will result in free/open imbalance errors when
fput is eventually called.

Signed-off-by: Marc Dionne 
Signed-off-by: David Howells 
Signed-off-by: Linus Torvalds

CacheFiles: Don't log lookup/create failing with ENOBUFS

2009-11-19T18:12:08+00:00

Don't log the CacheFiles lookup/create object routined failing with ENOBUFS as
under high memory load or high cache load they can do this quite a lot.  This
error simply means that the requested object cannot be created on disk due to
lack of space, or due to failure of the backing filesystem to find sufficient
resources.

Signed-off-by: David Howells

CacheFiles: Catch an overly long wait for an old active object

2009-11-19T18:12:05+00:00

Catch an overly long wait for an old, dying active object when we want to
replace it with a new one.  The probability is that all the slow-work threads
are hogged, and the delete can't get a look in.

What we do instead is:

 (1) if there's nothing in the slow work queue, we sleep until either the dying
     object has finished dying or there is something in the slow work queue
     behind which we can queue our object.

 (2) if there is something in the slow work queue, we return ETIMEDOUT to
     fscache_lookup_object(), which then puts us back on the slow work queue,
     presumably behind the deletion that we're blocked by.  We are then
     deferred for a while until we work our way back through the queue -
     without blocking a slow-work thread unnecessarily.

A backtrace similar to the following may appear in the log without this patch:

	INFO: task kslowd004:5711 blocked for more than 120 seconds.
	"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
	kslowd004     D 0000000000000000     0  5711      2 0x00000080
	 ffff88000340bb80 0000000000000046 ffff88002550d000 0000000000000000
	 ffff88002550d000 0000000000000007 ffff88000340bfd8 ffff88002550d2a8
	 000000000000ddf0 00000000000118c0 00000000000118c0 ffff88002550d2a8
	Call Trace:
	 [] ? trace_hardirqs_on+0xd/0xf
	 [] ? cachefiles_wait_bit+0x0/0xd [cachefiles]
	 [] cachefiles_wait_bit+0x9/0xd [cachefiles]
	 [] __wait_on_bit+0x43/0x76
	 [] ? ext3_xattr_get+0x1ec/0x270
	 [] out_of_line_wait_on_bit+0x69/0x74
	 [] ? cachefiles_wait_bit+0x0/0xd [cachefiles]
	 [] ? wake_bit_function+0x0/0x2e
	 [] cachefiles_mark_object_active+0x203/0x23b [cachefiles]
	 [] cachefiles_walk_to_object+0x558/0x827 [cachefiles]
	 [] cachefiles_lookup_object+0xac/0x12a [cachefiles]
	 [] fscache_lookup_object+0x1c7/0x214 [fscache]
	 [] fscache_object_state_machine+0xa5/0x52d [fscache]
	 [] fscache_object_slow_work_execute+0x5f/0xa0 [fscache]
	 [] slow_work_execute+0x18f/0x2d1
	 [] slow_work_thread+0x1c5/0x308
	 [] ? autoremove_wake_function+0x0/0x34
	 [] ? slow_work_thread+0x0/0x308
	 [] kthread+0x7a/0x82
	 [] child_rip+0xa/0x20
	 [] ? restore_args+0x0/0x30
	 [] ? kthread+0x0/0x82
	 [] ? child_rip+0x0/0x20
	1 lock held by kslowd004/5711:
	 #0:  (&sb->s_type->i_mutex_key#7/1){+.+.+.}, at: [] cachefiles_walk_to_object+0x1b3/0x827 [cachefiles]

Signed-off-by: David Howells

CacheFiles: Better showing of debugging information in active object problems

2009-11-19T18:12:02+00:00

Show more debugging information if cachefiles_mark_object_active() is asked to
activate an active object.

This may happen, for instance, if the netfs tries to register an object with
the same key multiple times.

The code is changed to (a) get the appropriate object lock to protect the
cookie pointer whilst we dereference it, and (b) get and display the cookie key
if available.

Signed-off-by: David Howells

CacheFiles: Mark parent directory locks as I_MUTEX_PARENT to keep lockdep happy

2009-11-19T18:11:58+00:00

Mark parent directory locks as I_MUTEX_PARENT in the callers of
cachefiles_bury_object() so that lockdep doesn't complain when that invokes
vfs_unlink():

=============================================
[ INFO: possible recursive locking detected ]
2.6.32-rc6-cachefs #47
---------------------------------------------
kslowd002/3089 is trying to acquire lock:
 (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [] vfs_unlink+0x8b/0x128

but task is already holding lock:
 (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [] cachefiles_walk_to_object+0x1b0/0x831 [cachefiles]

other info that might help us debug this:
1 lock held by kslowd002/3089:
 #0:  (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [] cachefiles_walk_to_object+0x1b0/0x831 [cachefiles]

stack backtrace:
Pid: 3089, comm: kslowd002 Not tainted 2.6.32-rc6-cachefs #47
Call Trace:
 [] __lock_acquire+0x1649/0x16e3
 [] ? inode_has_perm+0x5f/0x61
 [] lock_acquire+0x57/0x6d
 [] ? vfs_unlink+0x8b/0x128
 [] mutex_lock_nested+0x54/0x292
 [] ? vfs_unlink+0x8b/0x128
 [] ? selinux_inode_permission+0x8e/0x90
 [] ? security_inode_permission+0x1c/0x1e
 [] ? inode_permission+0x99/0xa5
 [] vfs_unlink+0x8b/0x128
 [] ? kfree+0xed/0xf9
 [] cachefiles_bury_object+0xb6/0x420 [cachefiles]
 [] ? trace_hardirqs_on+0xd/0xf
 [] ? cachefiles_check_object_xattr+0x233/0x293 [cachefiles]
 [] cachefiles_walk_to_object+0x4ff/0x831 [cachefiles]
 [] ? finish_task_switch+0x0/0xb2
 [] cachefiles_lookup_object+0xac/0x12a [cachefiles]
 [] fscache_lookup_object+0x1c7/0x214 [fscache]
 [] fscache_object_state_machine+0xa5/0x52d [fscache]
 [] fscache_object_slow_work_execute+0x5f/0xa0 [fscache]
 [] slow_work_execute+0x18f/0x2d1
 [] slow_work_thread+0x1c5/0x308
 [] ? autoremove_wake_function+0x0/0x34
 [] ? slow_work_thread+0x0/0x308
 [] kthread+0x7a/0x82
 [] child_rip+0xa/0x20
 [] ? restore_args+0x0/0x30
 [] ? kthread+0x0/0x82
 [] ? child_rip+0x0/0x20

Signed-off-by: Daivd Howells