blob: 07ea8d3e6ea2d2fc6f9c984d2077ac439c3453ac [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
26#include <asm/atomic.h>
27
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 struct hlist_node *pos;
40 __u32 new_mask = 0;
41
42 assert_spin_locked(&inode->i_lock);
43
Eric Paris841bdc12009-12-17 21:24:24 -050044 hlist_for_each_entry(mark, pos, &inode->i_fsnotify_marks, i.i_list)
45 new_mask |= mark->mask;
Eric Paris3be25f42009-05-21 17:01:26 -040046 inode->i_fsnotify_mask = new_mask;
47}
48
49/*
50 * Recalculate the inode->i_fsnotify_mask, or the mask of all FS_* event types
51 * any notifier is interested in hearing for this inode.
52 */
53void fsnotify_recalc_inode_mask(struct inode *inode)
54{
55 spin_lock(&inode->i_lock);
56 fsnotify_recalc_inode_mask_locked(inode);
57 spin_unlock(&inode->i_lock);
Eric Parisc28f7e52009-05-21 17:01:29 -040058
59 __fsnotify_update_child_dentry_flags(inode);
Eric Paris3be25f42009-05-21 17:01:26 -040060}
61
Eric Paris5444e292009-12-17 21:24:27 -050062void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark)
Eric Paris3be25f42009-05-21 17:01:26 -040063{
Eric Paris5444e292009-12-17 21:24:27 -050064 struct inode *inode = mark->i.inode;
Eric Paris3be25f42009-05-21 17:01:26 -040065
Eric Paris5444e292009-12-17 21:24:27 -050066 assert_spin_locked(&mark->lock);
67 assert_spin_locked(&mark->group->mark_lock);
Eric Paris3be25f42009-05-21 17:01:26 -040068
Eric Paris3be25f42009-05-21 17:01:26 -040069 spin_lock(&inode->i_lock);
70
Eric Parisa4c6e992010-07-28 10:18:38 -040071 hlist_del_init_rcu(&mark->i.i_list);
Eric Paris841bdc12009-12-17 21:24:24 -050072 mark->i.inode = NULL;
Eric Paris3be25f42009-05-21 17:01:26 -040073
74 /*
Eric Parise61ce862009-12-17 21:24:24 -050075 * this mark is now off the inode->i_fsnotify_marks list and we
Eric Paris3be25f42009-05-21 17:01:26 -040076 * hold the inode->i_lock, so this is the perfect time to update the
77 * inode->i_fsnotify_mask
78 */
79 fsnotify_recalc_inode_mask_locked(inode);
80
81 spin_unlock(&inode->i_lock);
Eric Paris3be25f42009-05-21 17:01:26 -040082}
83
84/*
85 * Given an inode, destroy all of the marks associated with that inode.
86 */
87void fsnotify_clear_marks_by_inode(struct inode *inode)
88{
Eric Paris841bdc12009-12-17 21:24:24 -050089 struct fsnotify_mark *mark, *lmark;
Eric Paris3be25f42009-05-21 17:01:26 -040090 struct hlist_node *pos, *n;
91 LIST_HEAD(free_list);
92
93 spin_lock(&inode->i_lock);
Eric Paris841bdc12009-12-17 21:24:24 -050094 hlist_for_each_entry_safe(mark, pos, n, &inode->i_fsnotify_marks, i.i_list) {
95 list_add(&mark->i.free_i_list, &free_list);
Eric Parisa4c6e992010-07-28 10:18:38 -040096 hlist_del_init_rcu(&mark->i.i_list);
Eric Paris841bdc12009-12-17 21:24:24 -050097 fsnotify_get_mark(mark);
Eric Paris3be25f42009-05-21 17:01:26 -040098 }
99 spin_unlock(&inode->i_lock);
100
Eric Paris841bdc12009-12-17 21:24:24 -0500101 list_for_each_entry_safe(mark, lmark, &free_list, i.free_i_list) {
102 fsnotify_destroy_mark(mark);
103 fsnotify_put_mark(mark);
Eric Paris3be25f42009-05-21 17:01:26 -0400104 }
105}
106
107/*
Eric Paris4d926042009-12-17 21:24:34 -0500108 * Given a group clear all of the inode marks associated with that group.
109 */
110void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group)
111{
112 fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_INODE);
113}
114
115/*
Eric Paris3be25f42009-05-21 17:01:26 -0400116 * given a group and inode, find the mark associated with that combination.
117 * if found take a reference to that mark and return it, else return NULL
118 */
Eric Paris5444e292009-12-17 21:24:27 -0500119struct fsnotify_mark *fsnotify_find_inode_mark_locked(struct fsnotify_group *group,
120 struct inode *inode)
Eric Paris3be25f42009-05-21 17:01:26 -0400121{
Eric Paris841bdc12009-12-17 21:24:24 -0500122 struct fsnotify_mark *mark;
Eric Paris3be25f42009-05-21 17:01:26 -0400123 struct hlist_node *pos;
124
125 assert_spin_locked(&inode->i_lock);
126
Eric Paris841bdc12009-12-17 21:24:24 -0500127 hlist_for_each_entry(mark, pos, &inode->i_fsnotify_marks, i.i_list) {
128 if (mark->group == group) {
129 fsnotify_get_mark(mark);
130 return mark;
Eric Paris3be25f42009-05-21 17:01:26 -0400131 }
132 }
133 return NULL;
134}
135
136/*
Andreas Gruenbacher35566082009-12-17 21:24:25 -0500137 * given a group and inode, find the mark associated with that combination.
138 * if found take a reference to that mark and return it, else return NULL
Eric Paris3be25f42009-05-21 17:01:26 -0400139 */
Eric Paris5444e292009-12-17 21:24:27 -0500140struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group,
141 struct inode *inode)
Eric Paris3be25f42009-05-21 17:01:26 -0400142{
Andreas Gruenbacher35566082009-12-17 21:24:25 -0500143 struct fsnotify_mark *mark;
144
145 spin_lock(&inode->i_lock);
Eric Paris5444e292009-12-17 21:24:27 -0500146 mark = fsnotify_find_inode_mark_locked(group, inode);
Andreas Gruenbacher35566082009-12-17 21:24:25 -0500147 spin_unlock(&inode->i_lock);
148
149 return mark;
Eric Paris3be25f42009-05-21 17:01:26 -0400150}
151
152/*
Eric Paris90b1e7a2009-12-17 21:24:33 -0500153 * If we are setting a mark mask on an inode mark we should pin the inode
154 * in memory.
Eric Paris3be25f42009-05-21 17:01:26 -0400155 */
Eric Paris90b1e7a2009-12-17 21:24:33 -0500156void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark,
157 __u32 mask)
Eric Paris3be25f42009-05-21 17:01:26 -0400158{
Eric Paris90b1e7a2009-12-17 21:24:33 -0500159 struct inode *inode;
160
161 assert_spin_locked(&mark->lock);
162
163 if (mask &&
164 mark->i.inode &&
165 !(mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) {
166 mark->flags |= FSNOTIFY_MARK_FLAG_OBJECT_PINNED;
167 inode = igrab(mark->i.inode);
168 /*
169 * we shouldn't be able to get here if the inode wasn't
170 * already safely held in memory. But bug in case it
171 * ever is wrong.
172 */
173 BUG_ON(!inode);
174 }
175}
176
177/*
Eric Paris0c6532e2010-07-28 10:18:38 -0400178 * Attach an initialized mark to a given inode.
Eric Paris3be25f42009-05-21 17:01:26 -0400179 * These marks may be used for the fsnotify backend to determine which
Eric Paris0c6532e2010-07-28 10:18:38 -0400180 * event types should be delivered to which group and for which inodes. These
Eric Paris6ad2d4e2010-10-28 17:21:56 -0400181 * marks are ordered according to priority, highest number first, and then by
182 * the group's location in memory.
Eric Paris3be25f42009-05-21 17:01:26 -0400183 */
Eric Paris5444e292009-12-17 21:24:27 -0500184int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
185 struct fsnotify_group *group, struct inode *inode,
186 int allow_dups)
Eric Paris3be25f42009-05-21 17:01:26 -0400187{
Eric Paris0c6532e2010-07-28 10:18:38 -0400188 struct fsnotify_mark *lmark;
189 struct hlist_node *node, *last = NULL;
Eric Paris3be25f42009-05-21 17:01:26 -0400190 int ret = 0;
191
Eric Paris700307a2010-07-28 10:18:38 -0400192 mark->flags |= FSNOTIFY_MARK_FLAG_INODE;
Eric Paris1ef5f132009-05-21 17:01:54 -0400193
Eric Paris5444e292009-12-17 21:24:27 -0500194 assert_spin_locked(&mark->lock);
195 assert_spin_locked(&group->mark_lock);
Eric Paris71314852009-12-17 21:24:23 -0500196
Eric Paris3be25f42009-05-21 17:01:26 -0400197 spin_lock(&inode->i_lock);
198
Eric Paris0c6532e2010-07-28 10:18:38 -0400199 mark->i.inode = inode;
Eric Paris9f0d7932009-09-11 13:03:19 -0400200
Eric Paris0c6532e2010-07-28 10:18:38 -0400201 /* is mark the first mark? */
202 if (hlist_empty(&inode->i_fsnotify_marks)) {
Eric Parisa4c6e992010-07-28 10:18:38 -0400203 hlist_add_head_rcu(&mark->i.i_list, &inode->i_fsnotify_marks);
Eric Paris0c6532e2010-07-28 10:18:38 -0400204 goto out;
Eric Paris3be25f42009-05-21 17:01:26 -0400205 }
206
Eric Paris0c6532e2010-07-28 10:18:38 -0400207 /* should mark be in the middle of the current list? */
208 hlist_for_each_entry(lmark, node, &inode->i_fsnotify_marks, i.i_list) {
209 last = node;
Eric Paris3be25f42009-05-21 17:01:26 -0400210
Eric Paris0c6532e2010-07-28 10:18:38 -0400211 if ((lmark->group == group) && !allow_dups) {
212 ret = -EEXIST;
213 goto out;
214 }
215
Eric Paris6ad2d4e2010-10-28 17:21:56 -0400216 if (mark->group->priority < lmark->group->priority)
217 continue;
218
219 if ((mark->group->priority == lmark->group->priority) &&
220 (mark->group < lmark->group))
Eric Paris0c6532e2010-07-28 10:18:38 -0400221 continue;
222
Eric Parisa4c6e992010-07-28 10:18:38 -0400223 hlist_add_before_rcu(&mark->i.i_list, &lmark->i.i_list);
Eric Paris0c6532e2010-07-28 10:18:38 -0400224 goto out;
225 }
226
227 BUG_ON(last == NULL);
228 /* mark should be the last entry. last is the current last entry */
Eric Parisa4c6e992010-07-28 10:18:38 -0400229 hlist_add_after_rcu(last, &mark->i.i_list);
Eric Paris0c6532e2010-07-28 10:18:38 -0400230out:
231 fsnotify_recalc_inode_mask_locked(inode);
Eric Paris3be25f42009-05-21 17:01:26 -0400232 spin_unlock(&inode->i_lock);
Eric Paris3be25f42009-05-21 17:01:26 -0400233
234 return ret;
235}
Eric Paris164bc612009-05-21 17:01:58 -0400236
237/**
238 * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes.
239 * @list: list of inodes being unmounted (sb->s_inodes)
240 *
Dave Chinner55fa6092011-03-22 22:23:40 +1100241 * Called during unmount with no locks held, so needs to be safe against
242 * concurrent modifiers. We temporarily drop inode_sb_list_lock and CAN block.
Eric Paris164bc612009-05-21 17:01:58 -0400243 */
244void fsnotify_unmount_inodes(struct list_head *list)
245{
246 struct inode *inode, *next_i, *need_iput = NULL;
247
Dave Chinner55fa6092011-03-22 22:23:40 +1100248 spin_lock(&inode_sb_list_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400249 list_for_each_entry_safe(inode, next_i, list, i_sb_list) {
250 struct inode *need_iput_tmp;
251
252 /*
Al Viroa4ffdde2010-06-02 17:38:30 -0400253 * We cannot __iget() an inode in state I_FREEING,
Eric Paris164bc612009-05-21 17:01:58 -0400254 * I_WILL_FREE, or I_NEW which is fine because by that point
255 * the inode cannot have any associated watches.
256 */
Dave Chinner250df6e2011-03-22 22:23:36 +1100257 spin_lock(&inode->i_lock);
258 if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
259 spin_unlock(&inode->i_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400260 continue;
Dave Chinner250df6e2011-03-22 22:23:36 +1100261 }
Eric Paris164bc612009-05-21 17:01:58 -0400262
263 /*
264 * If i_count is zero, the inode cannot have any watches and
265 * doing an __iget/iput with MS_ACTIVE clear would actually
266 * evict all inodes with zero i_count from icache which is
267 * unnecessarily violent and may in fact be illegal to do.
268 */
Dave Chinner250df6e2011-03-22 22:23:36 +1100269 if (!atomic_read(&inode->i_count)) {
270 spin_unlock(&inode->i_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400271 continue;
Dave Chinner250df6e2011-03-22 22:23:36 +1100272 }
Eric Paris164bc612009-05-21 17:01:58 -0400273
274 need_iput_tmp = need_iput;
275 need_iput = NULL;
276
277 /* In case fsnotify_inode_delete() drops a reference. */
278 if (inode != need_iput_tmp)
279 __iget(inode);
280 else
281 need_iput_tmp = NULL;
Dave Chinner250df6e2011-03-22 22:23:36 +1100282 spin_unlock(&inode->i_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400283
284 /* In case the dropping of a reference would nuke next_i. */
285 if ((&next_i->i_sb_list != list) &&
Dave Chinner250df6e2011-03-22 22:23:36 +1100286 atomic_read(&next_i->i_count)) {
287 spin_lock(&next_i->i_lock);
288 if (!(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
289 __iget(next_i);
290 need_iput = next_i;
291 }
292 spin_unlock(&next_i->i_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400293 }
294
295 /*
Dave Chinner55fa6092011-03-22 22:23:40 +1100296 * We can safely drop inode_sb_list_lock here because we hold
Eric Paris164bc612009-05-21 17:01:58 -0400297 * references on both inode and next_i. Also no new inodes
Dave Chinner55fa6092011-03-22 22:23:40 +1100298 * will be added since the umount has begun.
Eric Paris164bc612009-05-21 17:01:58 -0400299 */
Dave Chinner55fa6092011-03-22 22:23:40 +1100300 spin_unlock(&inode_sb_list_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400301
302 if (need_iput_tmp)
303 iput(need_iput_tmp);
304
305 /* for each watch, send FS_UNMOUNT and then remove it */
306 fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
307
308 fsnotify_inode_delete(inode);
309
310 iput(inode);
311
Dave Chinner55fa6092011-03-22 22:23:40 +1100312 spin_lock(&inode_sb_list_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400313 }
Dave Chinner55fa6092011-03-22 22:23:40 +1100314 spin_unlock(&inode_sb_list_lock);
Eric Paris164bc612009-05-21 17:01:58 -0400315}