Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / fs / notify / inotify / inotify_fsnotify.c
blob8b73332735ba5071f67c5f39b6079c506cdea6f7
1 /*
2 * fs/inotify_user.c - inotify support for userspace
4 * Authors:
5 * John McCutchan <ttb@tentacle.dhs.org>
6 * Robert Love <rml@novell.com>
8 * Copyright (C) 2005 John McCutchan
9 * Copyright 2006 Hewlett-Packard Development Company, L.P.
11 * Copyright (C) 2009 Eric Paris <Red Hat Inc>
12 * inotify was largely rewriten to make use of the fsnotify infrastructure
14 * This program is free software; you can redistribute it and/or modify it
15 * under the terms of the GNU General Public License as published by the
16 * Free Software Foundation; either version 2, or (at your option) any
17 * later version.
19 * This program is distributed in the hope that it will be useful, but
20 * WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 * General Public License for more details.
25 #include <linux/dcache.h> /* d_unlinked */
26 #include <linux/fs.h> /* struct inode */
27 #include <linux/fsnotify_backend.h>
28 #include <linux/inotify.h>
29 #include <linux/path.h> /* struct path */
30 #include <linux/slab.h> /* kmem_* */
31 #include <linux/types.h>
32 #include <linux/sched.h>
33 #include <linux/sched/user.h>
35 #include "inotify.h"
38 * Check if 2 events contain the same information.
40 static bool event_compare(struct fsnotify_event *old_fsn,
41 struct fsnotify_event *new_fsn)
43 struct inotify_event_info *old, *new;
45 if (old_fsn->mask & FS_IN_IGNORED)
46 return false;
47 old = INOTIFY_E(old_fsn);
48 new = INOTIFY_E(new_fsn);
49 if ((old_fsn->mask == new_fsn->mask) &&
50 (old_fsn->inode == new_fsn->inode) &&
51 (old->name_len == new->name_len) &&
52 (!old->name_len || !strcmp(old->name, new->name)))
53 return true;
54 return false;
57 static int inotify_merge(struct list_head *list,
58 struct fsnotify_event *event)
60 struct fsnotify_event *last_event;
62 last_event = list_entry(list->prev, struct fsnotify_event, list);
63 return event_compare(last_event, event);
66 int inotify_handle_event(struct fsnotify_group *group,
67 struct inode *inode,
68 struct fsnotify_mark *inode_mark,
69 struct fsnotify_mark *vfsmount_mark,
70 u32 mask, const void *data, int data_type,
71 const unsigned char *file_name, u32 cookie,
72 struct fsnotify_iter_info *iter_info)
74 struct inotify_inode_mark *i_mark;
75 struct inotify_event_info *event;
76 struct fsnotify_event *fsn_event;
77 int ret;
78 int len = 0;
79 int alloc_len = sizeof(struct inotify_event_info);
81 BUG_ON(vfsmount_mark);
83 if ((inode_mark->mask & FS_EXCL_UNLINK) &&
84 (data_type == FSNOTIFY_EVENT_PATH)) {
85 const struct path *path = data;
87 if (d_unlinked(path->dentry))
88 return 0;
90 if (file_name) {
91 len = strlen(file_name);
92 alloc_len += len + 1;
95 pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode,
96 mask);
98 i_mark = container_of(inode_mark, struct inotify_inode_mark,
99 fsn_mark);
101 event = kmalloc(alloc_len, GFP_KERNEL);
102 if (unlikely(!event))
103 return -ENOMEM;
105 fsn_event = &event->fse;
106 fsnotify_init_event(fsn_event, inode, mask);
107 event->wd = i_mark->wd;
108 event->sync_cookie = cookie;
109 event->name_len = len;
110 if (len)
111 strcpy(event->name, file_name);
113 ret = fsnotify_add_event(group, fsn_event, inotify_merge);
114 if (ret) {
115 /* Our event wasn't used in the end. Free it. */
116 fsnotify_destroy_event(group, fsn_event);
119 if (inode_mark->mask & IN_ONESHOT)
120 fsnotify_destroy_mark(inode_mark, group);
122 return 0;
125 static void inotify_freeing_mark(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group)
127 inotify_ignored_and_remove_idr(fsn_mark, group);
131 * This is NEVER supposed to be called. Inotify marks should either have been
132 * removed from the idr when the watch was removed or in the
133 * fsnotify_destroy_mark_by_group() call when the inotify instance was being
134 * torn down. This is only called if the idr is about to be freed but there
135 * are still marks in it.
137 static int idr_callback(int id, void *p, void *data)
139 struct fsnotify_mark *fsn_mark;
140 struct inotify_inode_mark *i_mark;
141 static bool warned = false;
143 if (warned)
144 return 0;
146 warned = true;
147 fsn_mark = p;
148 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
150 WARN(1, "inotify closing but id=%d for fsn_mark=%p in group=%p still in "
151 "idr. Probably leaking memory\n", id, p, data);
154 * I'm taking the liberty of assuming that the mark in question is a
155 * valid address and I'm dereferencing it. This might help to figure
156 * out why we got here and the panic is no worse than the original
157 * BUG() that was here.
159 if (fsn_mark)
160 printk(KERN_WARNING "fsn_mark->group=%p wd=%d\n",
161 fsn_mark->group, i_mark->wd);
162 return 0;
165 static void inotify_free_group_priv(struct fsnotify_group *group)
167 /* ideally the idr is empty and we won't hit the BUG in the callback */
168 idr_for_each(&group->inotify_data.idr, idr_callback, group);
169 idr_destroy(&group->inotify_data.idr);
170 if (group->inotify_data.ucounts)
171 dec_inotify_instances(group->inotify_data.ucounts);
174 static void inotify_free_event(struct fsnotify_event *fsn_event)
176 kfree(INOTIFY_E(fsn_event));
179 /* ding dong the mark is dead */
180 static void inotify_free_mark(struct fsnotify_mark *fsn_mark)
182 struct inotify_inode_mark *i_mark;
184 i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
186 kmem_cache_free(inotify_inode_mark_cachep, i_mark);
189 const struct fsnotify_ops inotify_fsnotify_ops = {
190 .handle_event = inotify_handle_event,
191 .free_group_priv = inotify_free_group_priv,
192 .free_event = inotify_free_event,
193 .freeing_mark = inotify_freeing_mark,
194 .free_mark = inotify_free_mark,