fs/aufs/hfsnotify.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2005-2021 Junjiro R. Okajima
   4  *
   5  * This program, aufs is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 /*
  20  * fsnotify for the lower directories
  21  */
  22
  23 #include "aufs.h"
  24
  25 /* FS_IN_IGNORED is unnecessary */
  26 static const __u32 AuHfsnMask = (FS_MOVED_TO | FS_MOVED_FROM | FS_DELETE
  27                                  | FS_CREATE | FS_EVENT_ON_CHILD);
  28 static DECLARE_WAIT_QUEUE_HEAD(au_hfsn_wq);
  29 static __cacheline_aligned_in_smp atomic64_t au_hfsn_ifree = ATOMIC64_INIT(0);
  30
  31 static void au_hfsn_free_mark(struct fsnotify_mark *mark)
  32 {
  33         struct au_hnotify *hn = container_of(mark, struct au_hnotify,
  34                                              hn_mark);
  35         /* AuDbg("here\n"); */
  36         au_cache_free_hnotify(hn);
  37         smp_mb__before_atomic(); /* for atomic64_dec */
  38         if (atomic64_dec_and_test(&au_hfsn_ifree))
  39                 wake_up(&au_hfsn_wq);
  40 }
  41
  42 static int au_hfsn_alloc(struct au_hinode *hinode)
  43 {
  44         int err;
  45         struct au_hnotify *hn;
  46         struct super_block *sb;
  47         struct au_branch *br;
  48         struct fsnotify_mark *mark;
  49         aufs_bindex_t bindex;
  50
  51         hn = hinode->hi_notify;
  52         sb = hn->hn_aufs_inode->i_sb;
  53         bindex = au_br_index(sb, hinode->hi_id);
  54         br = au_sbr(sb, bindex);
  55         AuDebugOn(!br->br_hfsn);
  56
  57         mark = &hn->hn_mark;
  58         fsnotify_init_mark(mark, br->br_hfsn->hfsn_group);
  59         mark->mask = AuHfsnMask;
  60         /*
  61          * by udba rename or rmdir, aufs assign a new inode to the known
  62          * h_inode, so specify 1 to allow dups.
  63          */
  64         lockdep_off();
  65         err = fsnotify_add_inode_mark(mark, hinode->hi_inode, /*allow_dups*/1);
  66         lockdep_on();
  67
  68         return err;
  69 }
  70
  71 static int au_hfsn_free(struct au_hinode *hinode, struct au_hnotify *hn)
  72 {
  73         struct fsnotify_mark *mark;
  74         unsigned long long ull;
  75         struct fsnotify_group *group;
  76
  77         ull = atomic64_inc_return(&au_hfsn_ifree);
  78         BUG_ON(!ull);
  79
  80         mark = &hn->hn_mark;
  81         spin_lock(&mark->lock);
  82         group = mark->group;
  83         fsnotify_get_group(group);
  84         spin_unlock(&mark->lock);
  85         lockdep_off();
  86         fsnotify_destroy_mark(mark, group);
  87         fsnotify_put_mark(mark);
  88         fsnotify_put_group(group);
  89         lockdep_on();
  90
  91         /* free hn by myself */
  92         return 0;
  93 }
  94
  95 /* ---------------------------------------------------------------------- */
  96
  97 static void au_hfsn_ctl(struct au_hinode *hinode, int do_set)
  98 {
  99         struct fsnotify_mark *mark;
 100
 101         mark = &hinode->hi_notify->hn_mark;
 102         spin_lock(&mark->lock);
 103         if (do_set) {
 104                 AuDebugOn(mark->mask & AuHfsnMask);
 105                 mark->mask |= AuHfsnMask;
 106         } else {
 107                 AuDebugOn(!(mark->mask & AuHfsnMask));
 108                 mark->mask &= ~AuHfsnMask;
 109         }
 110         spin_unlock(&mark->lock);
 111         /* fsnotify_recalc_inode_mask(hinode->hi_inode); */
 112 }
 113
 114 /* ---------------------------------------------------------------------- */
 115
 116 /* #define AuDbgHnotify */
 117 #ifdef AuDbgHnotify
 118 static char *au_hfsn_name(u32 mask)
 119 {
 120 #ifdef CONFIG_AUFS_DEBUG
 121 #define test_ret(flag)                          \
 122         do {                                    \
 123                 if (mask & flag)                \
 124                         return #flag;           \
 125         } while (0)
 126         test_ret(FS_ACCESS);
 127         test_ret(FS_MODIFY);
 128         test_ret(FS_ATTRIB);
 129         test_ret(FS_CLOSE_WRITE);
 130         test_ret(FS_CLOSE_NOWRITE);
 131         test_ret(FS_OPEN);
 132         test_ret(FS_MOVED_FROM);
 133         test_ret(FS_MOVED_TO);
 134         test_ret(FS_CREATE);
 135         test_ret(FS_DELETE);
 136         test_ret(FS_DELETE_SELF);
 137         test_ret(FS_MOVE_SELF);
 138         test_ret(FS_UNMOUNT);
 139         test_ret(FS_Q_OVERFLOW);
 140         test_ret(FS_IN_IGNORED);
 141         test_ret(FS_ISDIR);
 142         test_ret(FS_IN_ONESHOT);
 143         test_ret(FS_EVENT_ON_CHILD);
 144         return "";
 145 #undef test_ret
 146 #else
 147         return "??";
 148 #endif
 149 }
 150 #endif
 151
 152 /* ---------------------------------------------------------------------- */
 153
 154 static void au_hfsn_free_group(struct fsnotify_group *group)
 155 {
 156         struct au_br_hfsnotify *hfsn = group->private;
 157
 158         /* AuDbg("here\n"); */
 159         au_kfree_try_rcu(hfsn);
 160 }
 161
 162 static int au_hfsn_handle_event(struct fsnotify_group *group,
 163                                 u32 mask, const void *data, int data_type,
 164                                 struct inode *dir,
 165                                 const struct qstr *file_name, u32 cookie,
 166                                 struct fsnotify_iter_info *iter_info)
 167 {
 168         int err;
 169         struct au_hnotify *hnotify;
 170         struct inode *h_dir, *h_inode;
 171         struct fsnotify_mark *inode_mark;
 172
 173         AuDebugOn(data_type != FSNOTIFY_EVENT_INODE);
 174
 175         err = 0;
 176         /* if FS_UNMOUNT happens, there must be another bug */
 177         AuDebugOn(mask & FS_UNMOUNT);
 178         if (mask & (FS_IN_IGNORED | FS_UNMOUNT))
 179                 goto out;
 180
 181         h_dir = dir;
 182         h_inode = NULL;
 183 #ifdef AuDbgHnotify
 184         au_debug_on();
 185         if (1 || h_child_qstr.len != sizeof(AUFS_XINO_FNAME) - 1
 186             || strncmp(h_child_qstr.name, AUFS_XINO_FNAME, h_child_qstr.len)) {
 187                 AuDbg("i%lu, mask 0x%x %s, hcname %.*s, hi%lu\n",
 188                       h_dir->i_ino, mask, au_hfsn_name(mask),
 189                       AuLNPair(&h_child_qstr), h_inode ? h_inode->i_ino : 0);
 190                 /* WARN_ON(1); */
 191         }
 192         au_debug_off();
 193 #endif
 194
 195         inode_mark = fsnotify_iter_inode_mark(iter_info);
 196         AuDebugOn(!inode_mark);
 197         hnotify = container_of(inode_mark, struct au_hnotify, hn_mark);
 198         err = au_hnotify(h_dir, hnotify, mask, file_name, h_inode);
 199
 200 out:
 201         return err;
 202 }
 203
 204 static struct fsnotify_ops au_hfsn_ops = {
 205         .handle_event           = au_hfsn_handle_event,
 206         .free_group_priv        = au_hfsn_free_group,
 207         .free_mark              = au_hfsn_free_mark
 208 };
 209
 210 /* ---------------------------------------------------------------------- */
 211
 212 static void au_hfsn_fin_br(struct au_branch *br)
 213 {
 214         struct au_br_hfsnotify *hfsn;
 215
 216         hfsn = br->br_hfsn;
 217         if (hfsn) {
 218                 lockdep_off();
 219                 fsnotify_put_group(hfsn->hfsn_group);
 220                 lockdep_on();
 221         }
 222 }
 223
 224 static int au_hfsn_init_br(struct au_branch *br, int perm)
 225 {
 226         int err;
 227         struct fsnotify_group *group;
 228         struct au_br_hfsnotify *hfsn;
 229
 230         err = 0;
 231         br->br_hfsn = NULL;
 232         if (!au_br_hnotifyable(perm))
 233                 goto out;
 234
 235         err = -ENOMEM;
 236         hfsn = kmalloc(sizeof(*hfsn), GFP_NOFS);
 237         if (unlikely(!hfsn))
 238                 goto out;
 239
 240         err = 0;
 241         group = fsnotify_alloc_group(&au_hfsn_ops);
 242         if (IS_ERR(group)) {
 243                 err = PTR_ERR(group);
 244                 pr_err("fsnotify_alloc_group() failed, %d\n", err);
 245                 goto out_hfsn;
 246         }
 247
 248         group->private = hfsn;
 249         hfsn->hfsn_group = group;
 250         br->br_hfsn = hfsn;
 251         goto out; /* success */
 252
 253 out_hfsn:
 254         au_kfree_try_rcu(hfsn);
 255 out:
 256         return err;
 257 }
 258
 259 static int au_hfsn_reset_br(unsigned int udba, struct au_branch *br, int perm)
 260 {
 261         int err;
 262
 263         err = 0;
 264         if (!br->br_hfsn)
 265                 err = au_hfsn_init_br(br, perm);
 266
 267         return err;
 268 }
 269
 270 /* ---------------------------------------------------------------------- */
 271
 272 static void au_hfsn_fin(void)
 273 {
 274         AuDbg("au_hfsn_ifree %lld\n", (long long)atomic64_read(&au_hfsn_ifree));
 275         wait_event(au_hfsn_wq, !atomic64_read(&au_hfsn_ifree));
 276 }
 277
 278 const struct au_hnotify_op au_hnotify_op = {
 279         .ctl            = au_hfsn_ctl,
 280         .alloc          = au_hfsn_alloc,
 281         .free           = au_hfsn_free,
 282
 283         .fin            = au_hfsn_fin,
 284
 285         .reset_br       = au_hfsn_reset_br,
 286         .fin_br         = au_hfsn_fin_br,
 287         .init_br        = au_hfsn_init_br
 288 };