Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f44aebcc authored by Eric Paris's avatar Eric Paris
Browse files

inotify: use GFP_NOFS under potential memory pressure 



inotify can have a watchs removed under filesystem reclaim.

=================================
[ INFO: inconsistent lock state ]
2.6.31-rc2 #16
---------------------------------
inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
khubd/217 [HC0[0]:SC0[0]:HE1:SE1] takes:
 (iprune_mutex){+.+.?.}, at: [<c10ba899>] invalidate_inodes+0x20/0xe3
{IN-RECLAIM_FS-W} state was registered at:
  [<c10536ab>] __lock_acquire+0x2c9/0xac4
  [<c1053f45>] lock_acquire+0x9f/0xc2
  [<c1308872>] __mutex_lock_common+0x2d/0x323
  [<c1308c00>] mutex_lock_nested+0x2e/0x36
  [<c10ba6ff>] shrink_icache_memory+0x38/0x1b2
  [<c108bfb6>] shrink_slab+0xe2/0x13c
  [<c108c3e1>] kswapd+0x3d1/0x55d
  [<c10449b5>] kthread+0x66/0x6b
  [<c1003fdf>] kernel_thread_helper+0x7/0x10
  [<ffffffff>] 0xffffffff

Two things are needed to fix this.  First we need a method to tell
fsnotify_create_event() to use GFP_NOFS and second we need to stop using
one global IN_IGNORED event and allocate them one at a time.  This solves
current issues with multiple IN_IGNORED on a queue having tail drop
problems and simplifies the allocations since we don't have to worry about
two tasks opperating on the IGNORED event concurrently.

Signed-off-by: default avatarEric Paris <eparis@redhat.com>
parent c05594b6

fs/notify/fsnotify.c

+3 −1
Original line number Diff line number Diff line
@@ -159,7 +159,9 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const 
			if (!group->ops->should_send_event(group, to_tell, mask))

				continue;

			if (!event) {

				event = fsnotify_create_event(to_tell, mask, data, data_is, file_name, cookie);

				event = fsnotify_create_event(to_tell, mask, data,

							      data_is, file_name, cookie,

							      GFP_KERNEL);

				/* shit, we OOM'd and now we can't tell, maybe

				 * someday someone else will want to do something

				 * here */

fs/notify/inotify/inotify_user.c

+12 −6
Original line number Diff line number Diff line
@@ -57,7 +57,6 @@ int inotify_max_user_watches __read_mostly; 


static struct kmem_cache *inotify_inode_mark_cachep __read_mostly;

struct kmem_cache *event_priv_cachep __read_mostly;

static struct fsnotify_event *inotify_ignored_event;



/*

 * When inotify registers a new group it increments this and uses that
@@ -384,12 +383,19 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry, 
				    struct fsnotify_group *group)

{

	struct inotify_inode_mark_entry *ientry;

	struct fsnotify_event *ignored_event;

	struct inotify_event_private_data *event_priv;

	struct fsnotify_event_private_data *fsn_event_priv;



	ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL,

					      FSNOTIFY_EVENT_NONE, NULL, 0,

					      GFP_NOFS);

	if (!ignored_event)

		return;



	ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);



	event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL);

	event_priv = kmem_cache_alloc(event_priv_cachep, GFP_NOFS);

	if (unlikely(!event_priv))

		goto skip_send_ignore;
@@ -398,7 +404,7 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry, 
	fsn_event_priv->group = group;

	event_priv->wd = ientry->wd;



	fsnotify_add_notify_event(group, inotify_ignored_event, fsn_event_priv);

	fsnotify_add_notify_event(group, ignored_event, fsn_event_priv);



	/* did the private data get added? */

	if (list_empty(&fsn_event_priv->event_list))
@@ -406,6 +412,9 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry, 


skip_send_ignore:



	/* matches the reference taken when the event was created */

	fsnotify_put_event(ignored_event);



	/* remove this entry from the idr */

	inotify_remove_from_idr(group, ientry);
@@ -748,9 +757,6 @@ static int __init inotify_user_setup(void) 


	inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark_entry, SLAB_PANIC);

	event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC);

	inotify_ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL, FSNOTIFY_EVENT_NONE, NULL, 0);

	if (!inotify_ignored_event)

		panic("unable to allocate the inotify ignored event\n");



	inotify_max_queued_events = 16384;

	inotify_max_user_instances = 128;

fs/notify/notification.c

+5 −4
Original line number Diff line number Diff line
@@ -153,7 +153,7 @@ static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new 
				return true;

			break;

		case (FSNOTIFY_EVENT_NONE):

			return true;

			return false;

		};

	}

	return false;
@@ -345,18 +345,19 @@ static void initialize_event(struct fsnotify_event *event) 
 * @name the filename, if available

 */

struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, void *data,

					     int data_type, const char *name, u32 cookie)

					     int data_type, const char *name, u32 cookie,

					     gfp_t gfp)

{

	struct fsnotify_event *event;



	event = kmem_cache_alloc(fsnotify_event_cachep, GFP_KERNEL);

	event = kmem_cache_alloc(fsnotify_event_cachep, gfp);

	if (!event)

		return NULL;



	initialize_event(event);



	if (name) {

		event->file_name = kstrdup(name, GFP_KERNEL);

		event->file_name = kstrdup(name, gfp);

		if (!event->file_name) {

			kmem_cache_free(fsnotify_event_cachep, event);

			return NULL;

include/linux/fsnotify_backend.h

+1 −1
Original line number Diff line number Diff line
@@ -352,7 +352,7 @@ extern void fsnotify_unmount_inodes(struct list_head *list); 
/* put here because inotify does some weird stuff when destroying watches */

extern struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,

						    void *data, int data_is, const char *name,

						    u32 cookie);

						    u32 cookie, gfp_t gfp);



#else