1 files changed, 71 insertions, 38 deletions

diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index ff27a2965844..f30d9bbc2e1b 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -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
@@ -365,6 +364,17 @@ static int inotify_find_inode(const char __user *dirname, struct path *path, uns
         return error;
 }
 
+static void inotify_remove_from_idr(struct fsnotify_group *group,
+                                    struct inotify_inode_mark_entry *ientry)
+{
+        struct idr *idr;
+
+        spin_lock(&group->inotify_data.idr_lock);
+        idr = &group->inotify_data.idr;
+        idr_remove(idr, ientry->wd);
+        spin_unlock(&group->inotify_data.idr_lock);
+        ientry->wd = -1;
+}
 /*
  * Send IN_IGNORED for this wd, remove this wd from the idr, and drop the
  * internal reference help on the mark because it is in the idr.
@@ -373,13 +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;
-        struct idr *idr;
+
+        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;
 
@@ -388,7 +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))
@@ -396,14 +412,16 @@ 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 */
-        spin_lock(&group->inotify_data.idr_lock);
-        idr = &group->inotify_data.idr;
-        idr_remove(idr, ientry->wd);
-        spin_unlock(&group->inotify_data.idr_lock);
+        inotify_remove_from_idr(group, ientry);
 
         /* removed from idr, drop that reference */
         fsnotify_put_mark(entry);
+
+        atomic_dec(&group->inotify_data.user->inotify_watches);
 }
 
 /* ding dong the mark is dead */
@@ -418,6 +436,7 @@ static int inotify_update_watch(struct fsnotify_group *group, struct inode *inod
 {
         struct fsnotify_mark_entry *entry = NULL;
         struct inotify_inode_mark_entry *ientry;
+        struct inotify_inode_mark_entry *tmp_ientry;
         int ret = 0;
         int add = (arg & IN_MASK_ADD);
         __u32 mask;
@@ -428,54 +447,66 @@ static int inotify_update_watch(struct fsnotify_group *group, struct inode *inod
         if (unlikely(!mask))
                 return -EINVAL;
 
-        ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL);
-        if (unlikely(!ientry))
+        tmp_ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL);
+        if (unlikely(!tmp_ientry))
                 return -ENOMEM;
         /* we set the mask at the end after attaching it */
-        fsnotify_init_mark(&ientry->fsn_entry, inotify_free_mark);
-        ientry->wd = 0;
+        fsnotify_init_mark(&tmp_ientry->fsn_entry, inotify_free_mark);
+        tmp_ientry->wd = -1;
 
 find_entry:
         spin_lock(&inode->i_lock);
         entry = fsnotify_find_mark_entry(group, inode);
         spin_unlock(&inode->i_lock);
         if (entry) {
-                kmem_cache_free(inotify_inode_mark_cachep, ientry);
                 ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
         } else {
-                if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches) {
-                        ret = -ENOSPC;
-                        goto out_err;
-                }
-
-                ret = fsnotify_add_mark(&ientry->fsn_entry, group, inode);
-                if (ret == -EEXIST)
-                        goto find_entry;
-                else if (ret)
+                ret = -ENOSPC;
+                if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches)
                         goto out_err;
-
-                entry = &ientry->fsn_entry;
 retry:
                 ret = -ENOMEM;
                 if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL)))
                         goto out_err;
 
                 spin_lock(&group->inotify_data.idr_lock);
-                /* if entry is added to the idr we keep the reference obtained
-                 * through fsnotify_mark_add.  remember to drop this reference
-                 * when entry is removed from idr */
-                ret = idr_get_new_above(&group->inotify_data.idr, entry,
-                                        ++group->inotify_data.last_wd,
-                                        &ientry->wd);
+                ret = idr_get_new_above(&group->inotify_data.idr, &tmp_ientry->fsn_entry,
+                                        group->inotify_data.last_wd,
+                                        &tmp_ientry->wd);
                 spin_unlock(&group->inotify_data.idr_lock);
                 if (ret) {
                         if (ret == -EAGAIN)
                                 goto retry;
                         goto out_err;
                 }
+
+                ret = fsnotify_add_mark(&tmp_ientry->fsn_entry, group, inode);
+                if (ret) {
+                        inotify_remove_from_idr(group, tmp_ientry);
+                        if (ret == -EEXIST)
+                                goto find_entry;
+                        goto out_err;
+                }
+
+                /* tmp_ientry has been added to the inode, so we are all set up.
+                 * now we just need to make sure tmp_ientry doesn't get freed and
+                 * we need to set up entry and ientry so the generic code can
+                 * do its thing. */
+                ientry = tmp_ientry;
+                entry = &ientry->fsn_entry;
+                tmp_ientry = NULL;
+
                 atomic_inc(&group->inotify_data.user->inotify_watches);
+
+                /* update the idr hint */
+                group->inotify_data.last_wd = ientry->wd;
+
+                /* we put the mark on the idr, take a reference */
+                fsnotify_get_mark(entry);
         }
 
+        ret = ientry->wd;
+
         spin_lock(&entry->lock);
 
         old_mask = entry->mask;
@@ -506,14 +537,19 @@ retry:
                         fsnotify_recalc_group_mask(group);
         }
 
-        return ientry->wd;
+        /* this either matches fsnotify_find_mark_entry, or init_mark_entry
+         * depending on which path we took... */
+        fsnotify_put_mark(entry);
 
 out_err:
-        /* see this isn't supposed to happen, just kill the watch */
-        if (entry) {
-                fsnotify_destroy_mark_by_entry(entry);
-                fsnotify_put_mark(entry);
+        /* could be an error, could be that we found an existing mark */
+        if (tmp_ientry) {
+                /* on the idr but didn't make it on the inode */
+                if (tmp_ientry->wd != -1)
+                        inotify_remove_from_idr(group, tmp_ientry);
+                kmem_cache_free(inotify_inode_mark_cachep, tmp_ientry);
         }
+
         return ret;
 }
 
@@ -721,9 +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;