blob: 9ce062218de9cf2559c02b92a7a201224d1d67fc [file] [log] [blame]
Eric Paris3be25f42009-05-21 17:01:26 -04001/*
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
Eric Paris3be25f42009-05-21 17:01:26 -040019#include <linux/fs.h>
20#include <linux/init.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/mutex.h>
Eric Paris3be25f42009-05-21 17:01:26 -040024#include <linux/spinlock.h>
25
Arun Sharma600634972011-07-26 16:09:06 -070026#include <linux/atomic.h>
Eric Paris3be25f42009-05-21 17:01:26 -040027
28#include <linux/fsnotify_backend.h>
29#include "fsnotify.h"
30
Dave Chinner55fa6092011-03-22 22:23:40 +110031#include "../internal.h"
32
Eric Paris3be25f42009-05-21 17:01:26 -040033/*
34 * Recalculate the mask of events relevant to a given inode locked.
35 */
36static void fsnotify_recalc_inode_mask_locked(struct inode *inode)
37{
Eric Paris841bdc12009-12-17 21:24:24 -050038 struct fsnotify_mark *mark;
Eric Paris3be25f42009-05-21 17:01:26 -040039 __u32 new_mask = 0;
40
41 assert_spin_locked(&inode->i_lock);
42
Sasha Levinb67bfe02013-02-27 17:06:00 -080043 hlist_for_each_entry(mark, &inode->i_fsnotify_marks, i.i_list)
Eric Paris841bdc12009-12-17 21:24:24 -050044 new_mask |= mark->mask;
Eric Paris3be25f42009-05-21 17:01:26 -040045 inode->i_fsnotify_mask = new_mask;
46}
47
48/*
49 * Recalculate the inode->i_fsnotify_mask, or the mask of all FS_* event types
50 * any notifier is interested in hearing for this inode.
51 */
52void fsnotify_recalc_inode_mask(struct inode *inode)
53{
54 spin_lock(&inode->i_lock);
55 fsnotify_recalc_inode_mask_locked(inode);
56 spin_unlock(&inode->i_lock);
Eric Parisc28f7e52009-05-21 17:01:29 -040057
58 __fsnotify_update_child_dentry_flags(inode);
Eric Paris3be25f42009-05-21 17:01:26 -040059}
60
Eric Paris5444e292009-12-17 21:24:27 -050061void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark)
Eric Paris3be25f42009-05-21 17:01:26 -040062{
Eric Paris5444e292009-12-17 21:24:27 -050063 struct inode *inode = mark->i.inode;
Eric Paris3be25f42009-05-21 17:01:26 -040064
Lino Sanfilippo986ab092011-06-14 17:29:50 +020065 BUG_ON(!mutex_is_locked(&mark->group->mark_mutex));
Eric Paris5444e292009-12-17 21:24:27 -050066 assert_spin_locked(&mark->lock);
Eric Paris3be25f42009-05-21 17:01:26 -040067
Eric Paris3be25f42009-05-21 17:01:26 -040068 spin_lock(&inode->i_lock);
69
Eric Parisa4c6e992010-07-28 10:18:38 -040070 hlist_del_init_rcu(&mark->i.i_list);
Eric Paris841bdc12009-12-17 21:24:24 -050071 mark->i.inode = NULL;
Eric Paris3be25f42009-05-21 17:01:26 -040072
73 /*
Eric Parise61ce862009-12-17 21:24:24 -050074 * this mark is now off the inode->i_fsnotify_marks list and we
Eric Paris3be25f42009-05-21 17:01:26 -040075 * hold the inode->i_lock, so this is the perfect time to update the
76 * inode->i_fsnotify_mask
77 */
78 fsnotify_recalc_inode_mask_locked(inode);
79
80 spin_unlock(&inode->i_lock);
Eric Paris3be25f42009-05-21 17:01:26 -040081}
82
83/*
84 * Given an inode, destroy all of the marks associated with that inode.
85 */
86void fsnotify_clear_marks_by_inode(struct inode *inode)
87{
Eric Paris841bdc12009-12-17 21:24:24 -050088 struct fsnotify_mark *mark, *lmark;
Sasha Levinb67bfe02013-02-27 17:06:00 -080089 struct hlist_node *n;
Eric Paris3be25f42009-05-21 17:01:26 -040090 LIST_HEAD(free_list);
91
92 spin_lock(&inode->i_lock);
Sasha Levinb67bfe02013-02-27 17:06:00 -080093 hlist_for_each_entry_safe(mark, n, &inode->i_fsnotify_marks, i.i_list) {
Eric Paris841bdc12009-12-17 21:24:24 -050094 list_add(&mark->i.free_i_list, &free_list);
Eric Parisa4c6e992010-07-28 10:18:38 -040095 hlist_del_init_rcu(&mark->i.i_list);
Eric Paris841bdc12009-12-17 21:24:24 -050096 fsnotify_get_mark(mark);
Eric Paris3be25f42009-05-21 17:01:26 -040097 }
98 spin_unlock(&inode->i_lock);
99
Eric Paris841bdc12009-12-17 21:24:24 -0500100 list_for_each_entry_safe(mark, lmark, &free_list, i.free_i_list) {
Lino Sanfilippoe2a29942011-06-14 17:29:51 +0200101 struct fsnotify_group *group;
102
103 spin_lock(&mark->lock);
104 fsnotify_get_group(mark->group);
105 group = mark->group;
106 spin_unlock(&mark->lock);
107
108 fsnotify_destroy_mark(mark, group);
Eric Paris841bdc12009-12-17 21:24:24 -0500109 fsnotify_put_mark(mark);
Lino Sanfilippoe2a29942011-06-14 17:29:51 +0200110 fsnotify_put_group(group);
Eric Paris3be25f42009-05-21 17:01:26 -0400111 }
112}
113
114/*
Eric Paris4d926042009-12-17 21:24:34 -0500115 * Given a group clear all of the inode marks associated with that group.
116 */
117void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group)
118{
119 fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_INODE);
120}
121
122/*
Eric Paris3be25f42009-05-21 17:01:26 -0400123 * given a group and inode, find the mark associated with that combination.
124 * if found take a reference to that mark and return it, else return NULL
125 */
Tushar Beheraac5f1212012-12-17 15:59:40 -0800126static struct fsnotify_mark *fsnotify_find_inode_mark_locked(
127 struct fsnotify_group *group,
128 struct inode *inode)
Eric Paris3be25f42009-05-21 17:01:26 -0400129{
Eric Paris841bdc12009-12-17 21:24:24 -0500130 struct fsnotify_mark *mark;
Eric Paris3be25f42009-05-21 17:01:26 -0400131
132 assert_spin_locked(&inode->i_lock);
133
Sasha Levinb67bfe02013-02-27 17:06:00 -0800134 hlist_for_each_entry(mark, &inode->i_fsnotify_marks, i.i_list) {
Eric Paris841bdc12009-12-17 21:24:24 -0500135 if (mark->group == group) {
136 fsnotify_get_mark(mark);
137 return mark;
Eric Paris3be25f42009-05-21 17:01:26 -0400138 }
139 }
140 return NULL;
141}
142
143/*
Andreas Gruenbacher35566082009-12-17 21:24:25 -0500144 * given a group and inode, find the mark associated with that combination.
145 * if found take a reference to that mark and return it, else return NULL
Eric Paris3be25f42009-05-21 17:01:26 -0400146 */
Eric Paris5444e292009-12-17 21:24:27 -0500147struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group,
148 struct inode *inode)
Eric Paris3be25f42009-05-21 17:01:26 -0400149{
Andreas Gruenbacher35566082009-12-17 21:24:25 -0500150 struct fsnotify_mark *mark;
151
152 spin_lock(&inode->i_lock);
Eric Paris5444e292009-12-17 21:24:27 -0500153 mark = fsnotify_find_inode_mark_locked(group, inode);
Andreas Gruenbacher35566082009-12-17 21:24:25 -0500154 spin_unlock(&inode->i_lock);
155
156 return mark;
Eric Paris3be25f42009-05-21 17:01:26 -0400157}
158
159/*
Eric Paris90b1e7a2009-12-17 21:24:33 -0500160 * If we are setting a mark mask on an inode mark we should pin the inode
161 * in memory.
Eric Paris3be25f42009-05-21 17:01:26 -0400162 */
Eric Paris90b1e7a2009-12-17 21:24:33 -0500163void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark,
164 __u32 mask)
Eric Paris3be25f42009-05-21 17:01:26 -0400165{
Eric Paris90b1e7a2009-12-17 21:24:33 -0500166 struct inode *inode;
167
168 assert_spin_locked(&mark->lock);
169
170 if (mask &&
171 mark->i.inode &&
172 !(mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) {
173 mark->flags |= FSNOTIFY_MARK_FLAG_OBJECT_PINNED;
174 inode = igrab(mark->i.inode);
175 /*
176 * we shouldn't be able to get here if the inode wasn't
177 * already safely held in memory. But bug in case it
178 * ever is wrong.
179 */
180 BUG_ON(!inode);
181 }
182}
183
184/*
Eric Paris0c6532e2010-07-28 10:18:38 -0400185 * Attach an initialized mark to a given inode.
Eric Paris3be25f42009-05-21 17:01:26 -0400186 * These marks may be used for the fsnotify backend to determine which
Eric Paris0c6532e2010-07-28 10:18:38 -0400187 * event types should be delivered to which group and for which inodes. These
Eric Paris6ad2d4e2010-10-28 17:21:56 -0400188 * marks are ordered according to priority, highest number first, and then by
189 * the group's location in memory.
Eric Paris3be25f42009-05-21 17:01:26 -0400190 */
Eric Paris5444e292009-12-17 21:24:27 -0500191int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
192 struct fsnotify_group *group, struct inode *inode,
193 int allow_dups)
Eric Paris3be25f42009-05-21 17:01:26 -0400194{
Sasha Levinb67bfe02013-02-27 17:06:00 -0800195 struct fsnotify_mark *lmark, *last = NULL;
Eric Paris3be25f42009-05-21 17:01:26 -0400196 int ret = 0;
197
Eric Paris700307a2010-07-28 10:18:38 -0400198 mark->flags |= FSNOTIFY_MARK_FLAG_INODE;
Eric Paris1ef5f132009-05-21 17:01:54 -0400199
Lino Sanfilippo986ab092011-06-14 17:29:50 +0200200 BUG_ON(!mutex_is_locked(&group->mark_mutex));
Eric Paris5444e292009-12-17 21:24:27 -0500201 assert_spin_locked(&mark->lock);
Eric Paris71314852009-12-17 21:24:23 -0500202
Eric Paris3be25f42009-05-21 17:01:26 -0400203 spin_lock(&inode->i_lock);
204
Eric Paris0c6532e2010-07-28 10:18:38 -0400205 mark->i.inode = inode;
Eric Paris9f0d7932009-09-11 13:03:19 -0400206
Eric Paris0c6532e2010-07-28 10:18:38 -0400207 /* is mark the first mark? */
208 if (hlist_empty(&inode->i_fsnotify_marks)) {
Eric Parisa4c6e992010-07-28 10:18:38 -0400209 hlist_add_head_rcu(&mark->i.i_list, &inode->i_fsnotify_marks);
Eric Paris0c6532e2010-07-28 10:18:38 -0400210 goto out;
Eric Paris3be25f42009-05-21 17:01:26 -0400211 }
212
Eric Paris0c6532e2010-07-28 10:18:38 -0400213 /* should mark be in the middle of the current list? */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800214 hlist_for_each_entry(lmark, &inode->i_fsnotify_marks, i.i_list) {
215 last = lmark;
Eric Paris3be25f42009-05-21 17:01:26 -0400216
Eric Paris0c6532e2010-07-28 10:18:38 -0400217 if ((lmark->group == group) && !allow_dups) {
218 ret = -EEXIST;
219 goto out;
220 }
221
Eric Paris6ad2d4e2010-10-28 17:21:56 -0400222 if (mark->group->priority < lmark->group->priority)
223 continue;
224
225 if ((mark->group->priority == lmark->group->priority) &&
226 (mark->group < lmark->group))
Eric Paris0c6532e2010-07-28 10:18:38 -0400227 continue;
228
Eric Parisa4c6e992010-07-28 10:18:38 -0400229 hlist_add_before_rcu(&mark->i.i_list, &lmark->i.i_list);
Eric Paris0c6532e2010-07-28 10:18:38 -0400230 goto out;
231 }
232
233 BUG_ON(last == NULL);
234 /* mark should be the last entry. last is the current last entry */
Ken Helias1d023282014-08-06 16:09:16 -0700235 hlist_add_behind_rcu(&mark->i.i_list, &last->i.i_list);
Eric Paris0c6532e2010-07-28 10:18:38 -0400236out:
237 fsnotify_recalc_inode_mask_locked(inode);
Eric Paris3be25f42009-05-21 17:01:26 -0400238 spin_unlock(&inode->i_lock);
Eric Paris3be25f42009-05-21 17:01:26 -0400239
240 return ret;
241}
Eric Paris164bc612009-05-21 17:01:58 -0400242
243/**
244 * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes.
245 * @list: list of inodes being unmounted (sb->s_inodes)
246 *
Dave Chinner55fa6092011-03-22 22:23:40 +1100247 * Called during unmount with no locks held, so needs to be safe against
248 * concurrent modifiers. We temporarily drop inode_sb_list_lock and CAN block.
Eric Paris164bc612009-05-21 17:01:58 -0400249 */
250void fsnotify_unmount_inodes(struct list_head *list)
251{
252 struct inode *inode, *next_i, *need_iput = NULL;
253
Dave Chinner55fa6092011-03-22 22:23:40 +1100254 spin_lock(&inode_sb_list_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400255 list_for_each_entry_safe(inode, next_i, list, i_sb_list) {
256 struct inode *need_iput_tmp;
257
258 /*
Al Viroa4ffdde2010-06-02 17:38:30 -0400259 * We cannot __iget() an inode in state I_FREEING,
Eric Paris164bc612009-05-21 17:01:58 -0400260 * I_WILL_FREE, or I_NEW which is fine because by that point
261 * the inode cannot have any associated watches.
262 */
Dave Chinner250df6e2011-03-22 22:23:36 +1100263 spin_lock(&inode->i_lock);
264 if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
265 spin_unlock(&inode->i_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400266 continue;
Dave Chinner250df6e2011-03-22 22:23:36 +1100267 }
Eric Paris164bc612009-05-21 17:01:58 -0400268
269 /*
270 * If i_count is zero, the inode cannot have any watches and
271 * doing an __iget/iput with MS_ACTIVE clear would actually
272 * evict all inodes with zero i_count from icache which is
273 * unnecessarily violent and may in fact be illegal to do.
274 */
Dave Chinner250df6e2011-03-22 22:23:36 +1100275 if (!atomic_read(&inode->i_count)) {
276 spin_unlock(&inode->i_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400277 continue;
Dave Chinner250df6e2011-03-22 22:23:36 +1100278 }
Eric Paris164bc612009-05-21 17:01:58 -0400279
280 need_iput_tmp = need_iput;
281 need_iput = NULL;
282
283 /* In case fsnotify_inode_delete() drops a reference. */
284 if (inode != need_iput_tmp)
285 __iget(inode);
286 else
287 need_iput_tmp = NULL;
Dave Chinner250df6e2011-03-22 22:23:36 +1100288 spin_unlock(&inode->i_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400289
290 /* In case the dropping of a reference would nuke next_i. */
291 if ((&next_i->i_sb_list != list) &&
Dave Chinner250df6e2011-03-22 22:23:36 +1100292 atomic_read(&next_i->i_count)) {
293 spin_lock(&next_i->i_lock);
294 if (!(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
295 __iget(next_i);
296 need_iput = next_i;
297 }
298 spin_unlock(&next_i->i_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400299 }
300
301 /*
Dave Chinner55fa6092011-03-22 22:23:40 +1100302 * We can safely drop inode_sb_list_lock here because we hold
Eric Paris164bc612009-05-21 17:01:58 -0400303 * references on both inode and next_i. Also no new inodes
Dave Chinner55fa6092011-03-22 22:23:40 +1100304 * will be added since the umount has begun.
Eric Paris164bc612009-05-21 17:01:58 -0400305 */
Dave Chinner55fa6092011-03-22 22:23:40 +1100306 spin_unlock(&inode_sb_list_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400307
308 if (need_iput_tmp)
309 iput(need_iput_tmp);
310
311 /* for each watch, send FS_UNMOUNT and then remove it */
312 fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
313
314 fsnotify_inode_delete(inode);
315
316 iput(inode);
317
Dave Chinner55fa6092011-03-22 22:23:40 +1100318 spin_lock(&inode_sb_list_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400319 }
Dave Chinner55fa6092011-03-22 22:23:40 +1100320 spin_unlock(&inode_sb_list_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400321}