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 <>
parent c05594b6
......@@ -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))
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,
/* shit, we OOM'd and now we can't tell, maybe
* someday someone else will want to do something
* here */
......@@ -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,
if (!ignored_event)
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,
/* matches the reference taken when the event was created */
/* 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;
......@@ -153,7 +153,7 @@ static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new
return true;
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;
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;
......@@ -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);
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