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-rw-r--r--fs/notify/fsnotify.c92
1 files changed, 70 insertions, 22 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 23b5cfbeed50..a61aaa710825 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -21,6 +21,7 @@
21#include <linux/gfp.h> 21#include <linux/gfp.h>
22#include <linux/init.h> 22#include <linux/init.h>
23#include <linux/module.h> 23#include <linux/module.h>
24#include <linux/mount.h>
24#include <linux/srcu.h> 25#include <linux/srcu.h>
25 26
26#include <linux/fsnotify_backend.h> 27#include <linux/fsnotify_backend.h>
@@ -134,6 +135,45 @@ void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
134} 135}
135EXPORT_SYMBOL_GPL(__fsnotify_parent); 136EXPORT_SYMBOL_GPL(__fsnotify_parent);
136 137
138static void send_to_group(__u32 mask,
139 struct fsnotify_group *group,
140 void *data, int data_is, const char *file_name,
141 u32 cookie, struct fsnotify_event **event,
142 struct inode *to_tell)
143{
144 if (!group->ops->should_send_event(group, to_tell, mask,
145 data, data_is))
146 return;
147 if (!*event) {
148 *event = fsnotify_create_event(to_tell, mask, data,
149 data_is, file_name,
150 cookie, GFP_KERNEL);
151 /*
152 * shit, we OOM'd and now we can't tell, maybe
153 * someday someone else will want to do something
154 * here
155 */
156 if (!*event)
157 return;
158 }
159 group->ops->handle_event(group, *event);
160}
161
162static bool needed_by_vfsmount(__u32 test_mask, void *data, int data_is)
163{
164 struct path *path;
165
166 if (data_is == FSNOTIFY_EVENT_PATH)
167 path = (struct path *)data;
168 else if (data_is == FSNOTIFY_EVENT_FILE)
169 path = &((struct file *)data)->f_path;
170 else
171 return false;
172
173 /* hook in this when mnt->mnt_fsnotify_mask is defined */
174 /* return (test_mask & path->mnt->mnt_fsnotify_mask); */
175 return false;
176}
137/* 177/*
138 * This is the main call to fsnotify. The VFS calls into hook specific functions 178 * This is the main call to fsnotify. The VFS calls into hook specific functions
139 * in linux/fsnotify.h. Those functions then in turn call here. Here will call 179 * in linux/fsnotify.h. Those functions then in turn call here. Here will call
@@ -148,38 +188,46 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const
148 /* global tests shouldn't care about events on child only the specific event */ 188 /* global tests shouldn't care about events on child only the specific event */
149 __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD); 189 __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
150 190
151 if (list_empty(&fsnotify_inode_groups)) 191 /* if no fsnotify listeners, nothing to do */
152 return; 192 if (list_empty(&fsnotify_inode_groups) &&
193 list_empty(&fsnotify_vfsmount_groups))
194 return;
195
196 /* if none of the directed listeners or vfsmount listeners care */
197 if (!(test_mask & fsnotify_inode_mask) &&
198 !(test_mask & fsnotify_vfsmount_mask))
199 return;
200
201 /* if this inode's directed listeners don't care and nothing on the vfsmount
202 * listeners list cares, nothing to do */
203 if (!(test_mask & to_tell->i_fsnotify_mask) &&
204 !needed_by_vfsmount(test_mask, data, data_is))
205 return;
153 206
154 if (!(test_mask & fsnotify_inode_mask))
155 return;
156
157 if (!(test_mask & to_tell->i_fsnotify_mask))
158 return;
159 /* 207 /*
160 * SRCU!! the groups list is very very much read only and the path is 208 * SRCU!! the groups list is very very much read only and the path is
161 * very hot. The VAST majority of events are not going to need to do 209 * very hot. The VAST majority of events are not going to need to do
162 * anything other than walk the list so it's crazy to pre-allocate. 210 * anything other than walk the list so it's crazy to pre-allocate.
163 */ 211 */
164 idx = srcu_read_lock(&fsnotify_grp_srcu); 212 idx = srcu_read_lock(&fsnotify_grp_srcu);
165 list_for_each_entry_rcu(group, &fsnotify_inode_groups, inode_group_list) { 213
166 if (test_mask & group->mask) { 214 if (test_mask & to_tell->i_fsnotify_mask) {
167 if (!group->ops->should_send_event(group, to_tell, mask, 215 list_for_each_entry_rcu(group, &fsnotify_inode_groups, inode_group_list) {
168 data, data_is)) 216 if (test_mask & group->mask) {
169 continue; 217 send_to_group(mask, group, data, data_is,
170 if (!event) { 218 file_name, cookie, &event, to_tell);
171 event = fsnotify_create_event(to_tell, mask, data,
172 data_is, file_name, cookie,
173 GFP_KERNEL);
174 /* shit, we OOM'd and now we can't tell, maybe
175 * someday someone else will want to do something
176 * here */
177 if (!event)
178 break;
179 } 219 }
180 group->ops->handle_event(group, event);
181 } 220 }
182 } 221 }
222 if (needed_by_vfsmount(test_mask, data, data_is)) {
223 list_for_each_entry_rcu(group, &fsnotify_vfsmount_groups, vfsmount_group_list) {
224 if (test_mask & group->mask) {
225 send_to_group(mask, group, data, data_is,
226 file_name, cookie, &event, to_tell);
227 }
228 }
229 }
230
183 srcu_read_unlock(&fsnotify_grp_srcu, idx); 231 srcu_read_unlock(&fsnotify_grp_srcu, idx);
184 /* 232 /*
185 * fsnotify_create_event() took a reference so the event can't be cleaned 233 * fsnotify_create_event() took a reference so the event can't be cleaned