Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify
authorLinus Torvalds <torvalds@linux-foundation.org>
Mon, 27 Jul 2009 22:54:10 +0000 (15:54 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Mon, 27 Jul 2009 22:54:10 +0000 (15:54 -0700)
* 'for-linus' of git://git.infradead.org/users/eparis/notify:
  inotify: use GFP_NOFS under potential memory pressure
  fsnotify: fix inotify tail drop check with path entries
  inotify: check filename before dropping repeat events
  fsnotify: use def_bool in kconfig instead of letting the user choose
  inotify: fix error paths in inotify_update_watch
  inotify: do not leak inode marks in inotify_add_watch
  inotify: drop user watch count when a watch is removed

fs/notify/Kconfig
fs/notify/dnotify/Kconfig
fs/notify/fsnotify.c
fs/notify/inotify/Kconfig
fs/notify/inotify/inotify_user.c
fs/notify/notification.c
include/linux/fsnotify_backend.h

index 31dac7e..dffbb09 100644 (file)
@@ -1,15 +1,5 @@
 config FSNOTIFY
-       bool "Filesystem notification backend"
-       default y
-       ---help---
-          fsnotify is a backend for filesystem notification.  fsnotify does
-          not provide any userspace interface but does provide the basis
-          needed for other notification schemes such as dnotify, inotify,
-          and fanotify.
-
-          Say Y here to enable fsnotify suport.
-
-          If unsure, say Y.
+       def_bool n
 
 source "fs/notify/dnotify/Kconfig"
 source "fs/notify/inotify/Kconfig"
index 904ff8d..f9c1ca1 100644 (file)
@@ -1,6 +1,6 @@
 config DNOTIFY
        bool "Dnotify support"
-       depends on FSNOTIFY
+       select FSNOTIFY
        default y
        help
          Dnotify is a directory-based per-fd file change notification system
index ec2f7bd..037e878 100644 (file)
@@ -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 */
index 5356884..3e56dbf 100644 (file)
@@ -15,7 +15,7 @@ config INOTIFY
 
 config INOTIFY_USER
        bool "Inotify support for userspace"
-       depends on FSNOTIFY
+       select FSNOTIFY
        default y
        ---help---
          Say Y here to enable inotify support for userspace, including the
index ff27a29..f30d9bb 100644 (file)
@@ -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;
index 959b73e..5213685 100644 (file)
@@ -136,18 +136,24 @@ static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new
 {
        if ((old->mask == new->mask) &&
            (old->to_tell == new->to_tell) &&
-           (old->data_type == new->data_type)) {
+           (old->data_type == new->data_type) &&
+           (old->name_len == new->name_len)) {
                switch (old->data_type) {
                case (FSNOTIFY_EVENT_INODE):
-                       if (old->inode == new->inode)
+                       /* remember, after old was put on the wait_q we aren't
+                        * allowed to look at the inode any more, only thing
+                        * left to check was if the file_name is the same */
+                       if (old->name_len &&
+                           !strcmp(old->file_name, new->file_name))
                                return true;
                        break;
                case (FSNOTIFY_EVENT_PATH):
                        if ((old->path.mnt == new->path.mnt) &&
                            (old->path.dentry == new->path.dentry))
                                return true;
+                       break;
                case (FSNOTIFY_EVENT_NONE):
-                       return true;
+                       return false;
                };
        }
        return false;
@@ -339,18 +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;
index 6c3de99..4d6f47b 100644 (file)
@@ -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