1 /* 2 * fs/inotify_user.c - inotify support for userspace 3 * 4 * Authors: 5 * John McCutchan <ttb@tentacle.dhs.org> 6 * Robert Love <rml@novell.com> 7 * 8 * Copyright (C) 2005 John McCutchan 9 * Copyright 2006 Hewlett-Packard Development Company, L.P. 10 * 11 * Copyright (C) 2009 Eric Paris <Red Hat Inc> 12 * inotify was largely rewriten to make use of the fsnotify infrastructure 13 * 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. 18 * 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. 23 */ 24 25 #include <linux/fs.h> /* struct inode */ 26 #include <linux/fsnotify_backend.h> 27 #include <linux/inotify.h> 28 #include <linux/path.h> /* struct path */ 29 #include <linux/slab.h> /* kmem_* */ 30 #include <linux/types.h> 31 32 #include "inotify.h" 33 34 static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event) 35 { 36 struct fsnotify_mark_entry *entry; 37 struct inotify_inode_mark_entry *ientry; 38 struct inode *to_tell; 39 struct inotify_event_private_data *event_priv; 40 struct fsnotify_event_private_data *fsn_event_priv; 41 int wd, ret; 42 43 to_tell = event->to_tell; 44 45 spin_lock(&to_tell->i_lock); 46 entry = fsnotify_find_mark_entry(group, to_tell); 47 spin_unlock(&to_tell->i_lock); 48 /* race with watch removal? We already passes should_send */ 49 if (unlikely(!entry)) 50 return 0; 51 ientry = container_of(entry, struct inotify_inode_mark_entry, 52 fsn_entry); 53 wd = ientry->wd; 54 55 event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL); 56 if (unlikely(!event_priv)) 57 return -ENOMEM; 58 59 fsn_event_priv = &event_priv->fsnotify_event_priv_data; 60 61 fsn_event_priv->group = group; 62 event_priv->wd = wd; 63 64 ret = fsnotify_add_notify_event(group, event, fsn_event_priv); 65 /* EEXIST is not an error */ 66 if (ret == -EEXIST) 67 ret = 0; 68 69 /* did event_priv get attached? */ 70 if (list_empty(&fsn_event_priv->event_list)) 71 inotify_free_event_priv(fsn_event_priv); 72 73 /* 74 * If we hold the entry until after the event is on the queue 75 * IN_IGNORED won't be able to pass this event in the queue 76 */ 77 fsnotify_put_mark(entry); 78 79 return ret; 80 } 81 82 static void inotify_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group) 83 { 84 inotify_ignored_and_remove_idr(entry, group); 85 } 86 87 static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask) 88 { 89 struct fsnotify_mark_entry *entry; 90 bool send; 91 92 spin_lock(&inode->i_lock); 93 entry = fsnotify_find_mark_entry(group, inode); 94 spin_unlock(&inode->i_lock); 95 if (!entry) 96 return false; 97 98 mask = (mask & ~FS_EVENT_ON_CHILD); 99 send = (entry->mask & mask); 100 101 /* find took a reference */ 102 fsnotify_put_mark(entry); 103 104 return send; 105 } 106 107 static int idr_callback(int id, void *p, void *data) 108 { 109 BUG(); 110 return 0; 111 } 112 113 static void inotify_free_group_priv(struct fsnotify_group *group) 114 { 115 /* ideally the idr is empty and we won't hit the BUG in teh callback */ 116 idr_for_each(&group->inotify_data.idr, idr_callback, NULL); 117 idr_remove_all(&group->inotify_data.idr); 118 idr_destroy(&group->inotify_data.idr); 119 } 120 121 void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv) 122 { 123 struct inotify_event_private_data *event_priv; 124 125 126 event_priv = container_of(fsn_event_priv, struct inotify_event_private_data, 127 fsnotify_event_priv_data); 128 129 kmem_cache_free(event_priv_cachep, event_priv); 130 } 131 132 const struct fsnotify_ops inotify_fsnotify_ops = { 133 .handle_event = inotify_handle_event, 134 .should_send_event = inotify_should_send_event, 135 .free_group_priv = inotify_free_group_priv, 136 .free_event_priv = inotify_free_event_priv, 137 .freeing_mark = inotify_freeing_mark, 138 }; 139