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path: root/fs/notify/inotify/inotify_user.c
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Diffstat (limited to 'fs/notify/inotify/inotify_user.c')
-rw-r--r--fs/notify/inotify/inotify_user.c255
1 files changed, 175 insertions, 80 deletions
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index ff27a296584..0e781bc88d1 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -47,9 +47,6 @@
static struct vfsmount *inotify_mnt __read_mostly;
-/* this just sits here and wastes global memory. used to just pad userspace messages with zeros */
-static struct inotify_event nul_inotify_event;
-
/* these are configurable via /proc/sys/fs/inotify/ */
static int inotify_max_user_instances __read_mostly;
static int inotify_max_queued_events __read_mostly;
@@ -57,7 +54,6 @@ 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
@@ -200,8 +196,10 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
inotify_free_event_priv(fsn_priv);
}
- /* round up event->name_len so it is a multiple of event_size */
- name_len = roundup(event->name_len, event_size);
+ /* round up event->name_len so it is a multiple of event_size
+ * plus an extra byte for the terminating '\0'.
+ */
+ name_len = roundup(event->name_len + 1, event_size);
inotify_event.len = name_len;
inotify_event.mask = inotify_mask_to_arg(event->mask);
@@ -225,8 +223,8 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
return -EFAULT;
buf += event->name_len;
- /* fill userspace with 0's from nul_inotify_event */
- if (copy_to_user(buf, &nul_inotify_event, len_to_zero))
+ /* fill userspace with 0's */
+ if (clear_user(buf, len_to_zero))
return -EFAULT;
buf += len_to_zero;
event_size += name_len;
@@ -366,20 +364,71 @@ static int inotify_find_inode(const char __user *dirname, struct path *path, uns
}
/*
- * 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.
+ * Remove the mark from the idr (if present) and drop the reference
+ * on the mark because it was in the idr.
+ */
+static void inotify_remove_from_idr(struct fsnotify_group *group,
+ struct inotify_inode_mark_entry *ientry)
+{
+ struct idr *idr;
+ struct fsnotify_mark_entry *entry;
+ struct inotify_inode_mark_entry *found_ientry;
+ int wd;
+
+ spin_lock(&group->inotify_data.idr_lock);
+ idr = &group->inotify_data.idr;
+ wd = ientry->wd;
+
+ if (wd == -1)
+ goto out;
+
+ entry = idr_find(&group->inotify_data.idr, wd);
+ if (unlikely(!entry))
+ goto out;
+
+ found_ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
+ if (unlikely(found_ientry != ientry)) {
+ /* We found an entry in the idr with the right wd, but it's
+ * not the entry we were told to remove. eparis seriously
+ * fucked up somewhere. */
+ WARN_ON(1);
+ ientry->wd = -1;
+ goto out;
+ }
+
+ /* One ref for being in the idr, one ref held by the caller */
+ BUG_ON(atomic_read(&entry->refcnt) < 2);
+
+ idr_remove(idr, wd);
+ ientry->wd = -1;
+
+ /* removed from the idr, drop that ref */
+ fsnotify_put_mark(entry);
+out:
+ spin_unlock(&group->inotify_data.idr_lock);
+}
+
+/*
+ * Send IN_IGNORED for this wd, remove this wd from the idr.
*/
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;
+ int ret;
+
+ 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;
@@ -388,22 +437,19 @@ 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);
-
- /* did the private data get added? */
- if (list_empty(&fsn_event_priv->event_list))
+ ret = fsnotify_add_notify_event(group, ignored_event, fsn_event_priv);
+ if (ret)
inotify_free_event_priv(fsn_event_priv);
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 */
@@ -414,67 +460,29 @@ static void inotify_free_mark(struct fsnotify_mark_entry *entry)
kmem_cache_free(inotify_inode_mark_cachep, ientry);
}
-static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg)
+static int inotify_update_existing_watch(struct fsnotify_group *group,
+ struct inode *inode,
+ u32 arg)
{
- struct fsnotify_mark_entry *entry = NULL;
+ struct fsnotify_mark_entry *entry;
struct inotify_inode_mark_entry *ientry;
- int ret = 0;
- int add = (arg & IN_MASK_ADD);
- __u32 mask;
__u32 old_mask, new_mask;
+ __u32 mask;
+ int add = (arg & IN_MASK_ADD);
+ int ret;
/* don't allow invalid bits: we don't want flags set */
mask = inotify_arg_to_mask(arg);
if (unlikely(!mask))
return -EINVAL;
- ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL);
- if (unlikely(!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;
-
-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)
- goto out_err;
+ if (!entry)
+ return -ENOENT;
- 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);
- spin_unlock(&group->inotify_data.idr_lock);
- if (ret) {
- if (ret == -EAGAIN)
- goto retry;
- goto out_err;
- }
- atomic_inc(&group->inotify_data.user->inotify_watches);
- }
+ ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
spin_lock(&entry->lock);
@@ -506,14 +514,104 @@ retry:
fsnotify_recalc_group_mask(group);
}
- return ientry->wd;
+ /* return the wd */
+ ret = ientry->wd;
-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);
+ /* match the get from fsnotify_find_mark_entry() */
+ fsnotify_put_mark(entry);
+
+ return ret;
+}
+
+static int inotify_new_watch(struct fsnotify_group *group,
+ struct inode *inode,
+ u32 arg)
+{
+ struct inotify_inode_mark_entry *tmp_ientry;
+ __u32 mask;
+ int ret;
+
+ /* don't allow invalid bits: we don't want flags set */
+ mask = inotify_arg_to_mask(arg);
+ if (unlikely(!mask))
+ return -EINVAL;
+
+ tmp_ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL);
+ if (unlikely(!tmp_ientry))
+ return -ENOMEM;
+
+ fsnotify_init_mark(&tmp_ientry->fsn_entry, inotify_free_mark);
+ tmp_ientry->fsn_entry.mask = mask;
+ tmp_ientry->wd = -1;
+
+ ret = -ENOSPC;
+ if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches)
+ goto out_err;
+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, &tmp_ientry->fsn_entry,
+ group->inotify_data.last_wd,
+ &tmp_ientry->wd);
+ spin_unlock(&group->inotify_data.idr_lock);
+ if (ret) {
+ /* idr was out of memory allocate and try again */
+ if (ret == -EAGAIN)
+ goto retry;
+ goto out_err;
+ }
+
+ /* we put the mark on the idr, take a reference */
+ fsnotify_get_mark(&tmp_ientry->fsn_entry);
+
+ /* we are on the idr, now get on the inode */
+ ret = fsnotify_add_mark(&tmp_ientry->fsn_entry, group, inode);
+ if (ret) {
+ /* we failed to get on the inode, get off the idr */
+ inotify_remove_from_idr(group, tmp_ientry);
+ goto out_err;
}
+
+ /* update the idr hint, who cares about races, it's just a hint */
+ group->inotify_data.last_wd = tmp_ientry->wd;
+
+ /* increment the number of watches the user has */
+ atomic_inc(&group->inotify_data.user->inotify_watches);
+
+ /* return the watch descriptor for this new entry */
+ ret = tmp_ientry->wd;
+
+ /* match the ref from fsnotify_init_markentry() */
+ fsnotify_put_mark(&tmp_ientry->fsn_entry);
+
+out_err:
+ if (ret < 0)
+ kmem_cache_free(inotify_inode_mark_cachep, tmp_ientry);
+
+ return ret;
+}
+
+static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg)
+{
+ int ret = 0;
+
+retry:
+ /* try to update and existing watch with the new arg */
+ ret = inotify_update_existing_watch(group, inode, arg);
+ /* no mark present, try to add a new one */
+ if (ret == -ENOENT)
+ ret = inotify_new_watch(group, inode, arg);
+ /*
+ * inotify_new_watch could race with another thread which did an
+ * inotify_new_watch between the update_existing and the add watch
+ * here, go back and try to update an existing mark again.
+ */
+ if (ret == -EEXIST)
+ goto retry;
+
return ret;
}
@@ -532,7 +630,7 @@ static struct fsnotify_group *inotify_new_group(struct user_struct *user, unsign
spin_lock_init(&group->inotify_data.idr_lock);
idr_init(&group->inotify_data.idr);
- group->inotify_data.last_wd = 0;
+ group->inotify_data.last_wd = 1;
group->inotify_data.user = user;
group->inotify_data.fa = NULL;
@@ -721,9 +819,6 @@ 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;