1 files changed, 49 insertions, 30 deletions

diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index aff4214f16c3..726118a5845b 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -365,6 +365,17 @@ 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.
@@ -375,7 +386,6 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry,
         struct inotify_inode_mark_entry *ientry;
         struct inotify_event_private_data *event_priv;
         struct fsnotify_event_private_data *fsn_event_priv;
-        struct idr *idr;
 
         ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
 
@@ -397,10 +407,7 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry,
 skip_send_ignore:
 
         /* 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);
@@ -420,6 +427,7 @@ 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;
@@ -430,50 +438,60 @@ 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);
-                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);
         }
@@ -514,14 +532,15 @@ retry:
          * depending on which path we took... */
         fsnotify_put_mark(entry);
 
-        return ret;
-
 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;
 }