Eric Paris | 9058652 | 2009-05-21 17:01:20 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation; either version 2, or (at your option) |
| 7 | * any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; see the file COPYING. If not, write to |
| 16 | * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
| 17 | */ |
| 18 | |
| 19 | #include <linux/dcache.h> |
| 20 | #include <linux/fs.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 21 | #include <linux/gfp.h> |
Eric Paris | 9058652 | 2009-05-21 17:01:20 -0400 | [diff] [blame] | 22 | #include <linux/init.h> |
| 23 | #include <linux/module.h> |
Eric Paris | 7131485 | 2009-12-17 21:24:23 -0500 | [diff] [blame] | 24 | #include <linux/mount.h> |
Eric Paris | 9058652 | 2009-05-21 17:01:20 -0400 | [diff] [blame] | 25 | #include <linux/srcu.h> |
| 26 | |
| 27 | #include <linux/fsnotify_backend.h> |
| 28 | #include "fsnotify.h" |
| 29 | |
| 30 | /* |
Eric Paris | 3be25f4 | 2009-05-21 17:01:26 -0400 | [diff] [blame] | 31 | * Clear all of the marks on an inode when it is being evicted from core |
| 32 | */ |
| 33 | void __fsnotify_inode_delete(struct inode *inode) |
| 34 | { |
| 35 | fsnotify_clear_marks_by_inode(inode); |
| 36 | } |
| 37 | EXPORT_SYMBOL_GPL(__fsnotify_inode_delete); |
| 38 | |
Andreas Gruenbacher | ca9c726 | 2009-12-17 21:24:27 -0500 | [diff] [blame] | 39 | void __fsnotify_vfsmount_delete(struct vfsmount *mnt) |
| 40 | { |
| 41 | fsnotify_clear_marks_by_mount(mnt); |
| 42 | } |
| 43 | |
Eric Paris | 3be25f4 | 2009-05-21 17:01:26 -0400 | [diff] [blame] | 44 | /* |
Eric Paris | c28f7e5 | 2009-05-21 17:01:29 -0400 | [diff] [blame] | 45 | * Given an inode, first check if we care what happens to our children. Inotify |
| 46 | * and dnotify both tell their parents about events. If we care about any event |
| 47 | * on a child we run all of our children and set a dentry flag saying that the |
| 48 | * parent cares. Thus when an event happens on a child it can quickly tell if |
| 49 | * if there is a need to find a parent and send the event to the parent. |
| 50 | */ |
| 51 | void __fsnotify_update_child_dentry_flags(struct inode *inode) |
| 52 | { |
| 53 | struct dentry *alias; |
| 54 | int watched; |
| 55 | |
| 56 | if (!S_ISDIR(inode->i_mode)) |
| 57 | return; |
| 58 | |
| 59 | /* determine if the children should tell inode about their events */ |
| 60 | watched = fsnotify_inode_watches_children(inode); |
| 61 | |
| 62 | spin_lock(&dcache_lock); |
| 63 | /* run all of the dentries associated with this inode. Since this is a |
| 64 | * directory, there damn well better only be one item on this list */ |
| 65 | list_for_each_entry(alias, &inode->i_dentry, d_alias) { |
| 66 | struct dentry *child; |
| 67 | |
| 68 | /* run all of the children of the original inode and fix their |
| 69 | * d_flags to indicate parental interest (their parent is the |
| 70 | * original inode) */ |
| 71 | list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) { |
| 72 | if (!child->d_inode) |
| 73 | continue; |
| 74 | |
| 75 | spin_lock(&child->d_lock); |
| 76 | if (watched) |
| 77 | child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED; |
| 78 | else |
| 79 | child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED; |
| 80 | spin_unlock(&child->d_lock); |
| 81 | } |
| 82 | } |
| 83 | spin_unlock(&dcache_lock); |
| 84 | } |
| 85 | |
| 86 | /* Notify this dentry's parent about a child's events. */ |
Eric Paris | 3bcf386 | 2010-07-28 10:18:37 -0400 | [diff] [blame] | 87 | void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask) |
Eric Paris | c28f7e5 | 2009-05-21 17:01:29 -0400 | [diff] [blame] | 88 | { |
| 89 | struct dentry *parent; |
| 90 | struct inode *p_inode; |
| 91 | bool send = false; |
| 92 | bool should_update_children = false; |
| 93 | |
Andreas Gruenbacher | 72acc85 | 2009-12-17 21:24:24 -0500 | [diff] [blame] | 94 | if (!dentry) |
Eric Paris | 3bcf386 | 2010-07-28 10:18:37 -0400 | [diff] [blame] | 95 | dentry = file->f_path.dentry; |
Eric Paris | 28c60e3 | 2009-12-17 21:24:21 -0500 | [diff] [blame] | 96 | |
Eric Paris | c28f7e5 | 2009-05-21 17:01:29 -0400 | [diff] [blame] | 97 | if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED)) |
| 98 | return; |
| 99 | |
| 100 | spin_lock(&dentry->d_lock); |
| 101 | parent = dentry->d_parent; |
| 102 | p_inode = parent->d_inode; |
| 103 | |
| 104 | if (fsnotify_inode_watches_children(p_inode)) { |
| 105 | if (p_inode->i_fsnotify_mask & mask) { |
| 106 | dget(parent); |
| 107 | send = true; |
| 108 | } |
| 109 | } else { |
| 110 | /* |
| 111 | * The parent doesn't care about events on it's children but |
| 112 | * at least one child thought it did. We need to run all the |
| 113 | * children and update their d_flags to let them know p_inode |
| 114 | * doesn't care about them any more. |
| 115 | */ |
| 116 | dget(parent); |
| 117 | should_update_children = true; |
| 118 | } |
| 119 | |
| 120 | spin_unlock(&dentry->d_lock); |
| 121 | |
| 122 | if (send) { |
| 123 | /* we are notifying a parent so come up with the new mask which |
| 124 | * specifies these are events which came from a child. */ |
| 125 | mask |= FS_EVENT_ON_CHILD; |
| 126 | |
Eric Paris | 3bcf386 | 2010-07-28 10:18:37 -0400 | [diff] [blame] | 127 | if (file) |
| 128 | fsnotify(p_inode, mask, file, FSNOTIFY_EVENT_FILE, |
Eric Paris | 28c60e3 | 2009-12-17 21:24:21 -0500 | [diff] [blame] | 129 | dentry->d_name.name, 0); |
| 130 | else |
| 131 | fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE, |
| 132 | dentry->d_name.name, 0); |
Eric Paris | c28f7e5 | 2009-05-21 17:01:29 -0400 | [diff] [blame] | 133 | dput(parent); |
| 134 | } |
| 135 | |
| 136 | if (unlikely(should_update_children)) { |
| 137 | __fsnotify_update_child_dentry_flags(p_inode); |
| 138 | dput(parent); |
| 139 | } |
| 140 | } |
| 141 | EXPORT_SYMBOL_GPL(__fsnotify_parent); |
| 142 | |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 143 | static int send_to_group(struct inode *to_tell, struct vfsmount *mnt, |
| 144 | struct fsnotify_mark *mark, |
| 145 | __u32 mask, void *data, |
| 146 | int data_is, u32 cookie, |
Eric Paris | 3a9b16b | 2010-07-28 10:18:38 -0400 | [diff] [blame] | 147 | const unsigned char *file_name, |
Eric Paris | c4ec54b | 2009-12-17 21:24:34 -0500 | [diff] [blame] | 148 | struct fsnotify_event **event) |
Eric Paris | 7131485 | 2009-12-17 21:24:23 -0500 | [diff] [blame] | 149 | { |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 150 | struct fsnotify_group *group = mark->group; |
| 151 | __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD); |
| 152 | |
Eric Paris | 3a9b16b | 2010-07-28 10:18:38 -0400 | [diff] [blame] | 153 | pr_debug("%s: group=%p to_tell=%p mnt=%p mark=%p mask=%x data=%p" |
| 154 | " data_is=%d cookie=%d event=%p\n", __func__, group, to_tell, |
| 155 | mnt, mark, mask, data, data_is, cookie, *event); |
Eric Paris | 5ba08e2 | 2010-07-28 10:18:37 -0400 | [diff] [blame] | 156 | |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 157 | if ((mask & FS_MODIFY) && |
| 158 | !(mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) |
| 159 | mark->ignored_mask = 0; |
| 160 | |
| 161 | if (!(test_mask & mark->mask & ~mark->ignored_mask)) |
| 162 | return 0; |
| 163 | |
Eric Paris | 2612abb | 2010-07-28 10:18:39 -0400 | [diff] [blame] | 164 | if (group->ops->should_send_event(group, to_tell, mnt, mark, mask, |
| 165 | data, data_is) == false) |
Eric Paris | c4ec54b | 2009-12-17 21:24:34 -0500 | [diff] [blame] | 166 | return 0; |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 167 | |
Eric Paris | 7131485 | 2009-12-17 21:24:23 -0500 | [diff] [blame] | 168 | if (!*event) { |
| 169 | *event = fsnotify_create_event(to_tell, mask, data, |
| 170 | data_is, file_name, |
| 171 | cookie, GFP_KERNEL); |
Eric Paris | 7131485 | 2009-12-17 21:24:23 -0500 | [diff] [blame] | 172 | if (!*event) |
Eric Paris | c4ec54b | 2009-12-17 21:24:34 -0500 | [diff] [blame] | 173 | return -ENOMEM; |
Eric Paris | 7131485 | 2009-12-17 21:24:23 -0500 | [diff] [blame] | 174 | } |
Eric Paris | 3a9b16b | 2010-07-28 10:18:38 -0400 | [diff] [blame] | 175 | return group->ops->handle_event(group, mark, *event); |
Eric Paris | 7131485 | 2009-12-17 21:24:23 -0500 | [diff] [blame] | 176 | } |
| 177 | |
Eric Paris | c28f7e5 | 2009-05-21 17:01:29 -0400 | [diff] [blame] | 178 | /* |
Eric Paris | 9058652 | 2009-05-21 17:01:20 -0400 | [diff] [blame] | 179 | * This is the main call to fsnotify. The VFS calls into hook specific functions |
| 180 | * in linux/fsnotify.h. Those functions then in turn call here. Here will call |
| 181 | * out to all of the registered fsnotify_group. Those groups can then use the |
| 182 | * notification event in whatever means they feel necessary. |
| 183 | */ |
Eric Paris | c4ec54b | 2009-12-17 21:24:34 -0500 | [diff] [blame] | 184 | int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, |
| 185 | const unsigned char *file_name, u32 cookie) |
Eric Paris | 9058652 | 2009-05-21 17:01:20 -0400 | [diff] [blame] | 186 | { |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 187 | struct hlist_node *inode_node, *vfsmount_node; |
| 188 | struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL; |
| 189 | struct fsnotify_group *inode_group, *vfsmount_group; |
Eric Paris | 9058652 | 2009-05-21 17:01:20 -0400 | [diff] [blame] | 190 | struct fsnotify_event *event = NULL; |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 191 | struct vfsmount *mnt; |
Eric Paris | c4ec54b | 2009-12-17 21:24:34 -0500 | [diff] [blame] | 192 | int idx, ret = 0; |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 193 | bool used_inode = false, used_vfsmount = false; |
Eric Paris | e42e277 | 2009-06-11 11:09:47 -0400 | [diff] [blame] | 194 | /* global tests shouldn't care about events on child only the specific event */ |
| 195 | __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD); |
Eric Paris | 9058652 | 2009-05-21 17:01:20 -0400 | [diff] [blame] | 196 | |
Eric Paris | 3bcf386 | 2010-07-28 10:18:37 -0400 | [diff] [blame] | 197 | if (data_is == FSNOTIFY_EVENT_FILE) |
| 198 | mnt = ((struct file *)data)->f_path.mnt; |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 199 | else |
| 200 | mnt = NULL; |
| 201 | |
| 202 | /* |
| 203 | * if this is a modify event we may need to clear the ignored masks |
| 204 | * otherwise return if neither the inode nor the vfsmount care about |
| 205 | * this type of event. |
| 206 | */ |
| 207 | if (!(mask & FS_MODIFY) && |
| 208 | !(test_mask & to_tell->i_fsnotify_mask) && |
| 209 | !(mnt && test_mask & mnt->mnt_fsnotify_mask)) |
| 210 | return 0; |
Eric Paris | 3a9fb89 | 2009-12-17 21:24:23 -0500 | [diff] [blame] | 211 | |
Eric Paris | 75c1be4 | 2010-07-28 10:18:38 -0400 | [diff] [blame] | 212 | idx = srcu_read_lock(&fsnotify_mark_srcu); |
Eric Paris | 7131485 | 2009-12-17 21:24:23 -0500 | [diff] [blame] | 213 | |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 214 | if ((mask & FS_MODIFY) || |
| 215 | (test_mask & to_tell->i_fsnotify_mask)) |
| 216 | inode_node = to_tell->i_fsnotify_marks.first; |
| 217 | else |
| 218 | inode_node = NULL; |
Eric Paris | 75c1be4 | 2010-07-28 10:18:38 -0400 | [diff] [blame] | 219 | |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 220 | if (mnt) { |
| 221 | if ((mask & FS_MODIFY) || |
| 222 | (test_mask & mnt->mnt_fsnotify_mask)) |
| 223 | vfsmount_node = mnt->mnt_fsnotify_marks.first; |
| 224 | else |
| 225 | vfsmount_node = NULL; |
| 226 | } else { |
| 227 | mnt = NULL; |
| 228 | vfsmount_node = NULL; |
Eric Paris | 9058652 | 2009-05-21 17:01:20 -0400 | [diff] [blame] | 229 | } |
Eric Paris | 75c1be4 | 2010-07-28 10:18:38 -0400 | [diff] [blame] | 230 | |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 231 | while (inode_node || vfsmount_node) { |
| 232 | if (inode_node) { |
| 233 | inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu), |
| 234 | struct fsnotify_mark, i.i_list); |
| 235 | inode_group = inode_mark->group; |
| 236 | } else |
| 237 | inode_group = (void *)-1; |
Eric Paris | 75c1be4 | 2010-07-28 10:18:38 -0400 | [diff] [blame] | 238 | |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 239 | if (vfsmount_node) { |
| 240 | vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu), |
| 241 | struct fsnotify_mark, m.m_list); |
| 242 | vfsmount_group = vfsmount_mark->group; |
| 243 | } else |
| 244 | vfsmount_group = (void *)-1; |
Eric Paris | 75c1be4 | 2010-07-28 10:18:38 -0400 | [diff] [blame] | 245 | |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 246 | if (inode_group < vfsmount_group) { |
| 247 | /* handle inode */ |
| 248 | send_to_group(to_tell, NULL, inode_mark, mask, data, |
| 249 | data_is, cookie, file_name, &event); |
| 250 | used_inode = true; |
| 251 | } else if (vfsmount_group < inode_group) { |
| 252 | send_to_group(to_tell, mnt, vfsmount_mark, mask, data, |
| 253 | data_is, cookie, file_name, &event); |
| 254 | used_vfsmount = true; |
| 255 | } else { |
| 256 | send_to_group(to_tell, mnt, vfsmount_mark, mask, data, |
| 257 | data_is, cookie, file_name, &event); |
| 258 | used_vfsmount = true; |
| 259 | send_to_group(to_tell, NULL, inode_mark, mask, data, |
| 260 | data_is, cookie, file_name, &event); |
| 261 | used_inode = true; |
Eric Paris | 7131485 | 2009-12-17 21:24:23 -0500 | [diff] [blame] | 262 | } |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 263 | |
| 264 | if (used_inode) |
| 265 | inode_node = inode_node->next; |
| 266 | if (used_vfsmount) |
| 267 | vfsmount_node = vfsmount_node->next; |
Eric Paris | 7131485 | 2009-12-17 21:24:23 -0500 | [diff] [blame] | 268 | } |
Eric Paris | 613a807 | 2010-07-28 10:18:39 -0400 | [diff] [blame^] | 269 | |
Eric Paris | 75c1be4 | 2010-07-28 10:18:38 -0400 | [diff] [blame] | 270 | srcu_read_unlock(&fsnotify_mark_srcu, idx); |
Eric Paris | 9058652 | 2009-05-21 17:01:20 -0400 | [diff] [blame] | 271 | /* |
| 272 | * fsnotify_create_event() took a reference so the event can't be cleaned |
| 273 | * up while we are still trying to add it to lists, drop that one. |
| 274 | */ |
| 275 | if (event) |
| 276 | fsnotify_put_event(event); |
Eric Paris | c4ec54b | 2009-12-17 21:24:34 -0500 | [diff] [blame] | 277 | |
Jean-Christophe Dubois | 98b5c10 | 2010-03-23 08:08:09 +0100 | [diff] [blame] | 278 | return ret; |
Eric Paris | 9058652 | 2009-05-21 17:01:20 -0400 | [diff] [blame] | 279 | } |
| 280 | EXPORT_SYMBOL_GPL(fsnotify); |
| 281 | |
| 282 | static __init int fsnotify_init(void) |
| 283 | { |
Eric Paris | 75c1be4 | 2010-07-28 10:18:38 -0400 | [diff] [blame] | 284 | int ret; |
| 285 | |
Eric Paris | 20dee62 | 2010-07-28 10:18:37 -0400 | [diff] [blame] | 286 | BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23); |
| 287 | |
Eric Paris | 75c1be4 | 2010-07-28 10:18:38 -0400 | [diff] [blame] | 288 | ret = init_srcu_struct(&fsnotify_mark_srcu); |
| 289 | if (ret) |
| 290 | panic("initializing fsnotify_mark_srcu"); |
| 291 | |
| 292 | return 0; |
Eric Paris | 9058652 | 2009-05-21 17:01:20 -0400 | [diff] [blame] | 293 | } |
Eric Paris | 75c1be4 | 2010-07-28 10:18:38 -0400 | [diff] [blame] | 294 | core_initcall(fsnotify_init); |