fs/aufs/hfsnotify.c

   1 /*
   2  * Copyright (C) 2005-2016 Junjiro R. Okajima
   3  *
   4  * This program, aufs 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 of the License, or
   7  * (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 /*
  19  * fsnotify for the lower directories
  20  */
  21
  22 #include "aufs.h"
  23
  24 /* FS_IN_IGNORED is unnecessary */
  25 static const __u32 AuHfsnMask = (FS_MOVED_TO | FS_MOVED_FROM | FS_DELETE
  26                                  | FS_CREATE | FS_EVENT_ON_CHILD);
  27 static DECLARE_WAIT_QUEUE_HEAD(au_hfsn_wq);
  28 static __cacheline_aligned_in_smp atomic64_t au_hfsn_ifree = ATOMIC64_INIT(0);
  29
  30 static void au_hfsn_free_mark(struct fsnotify_mark *mark)
  31 {
  32         struct au_hnotify *hn = container_of(mark, struct au_hnotify,
  33                                              hn_mark);
  34         /* AuDbg("here\n"); */
  35         au_cache_dfree_hnotify(hn);
  36         smp_mb__before_atomic();
  37         if (atomic64_dec_and_test(&au_hfsn_ifree))
  38                 wake_up(&au_hfsn_wq);
  39 }
  40
  41 static int au_hfsn_alloc(struct au_hinode *hinode)
  42 {
  43         int err;
  44         struct au_hnotify *hn;
  45         struct super_block *sb;
  46         struct au_branch *br;
  47         struct fsnotify_mark *mark;
  48         aufs_bindex_t bindex;
  49
  50         hn = hinode->hi_notify;
  51         sb = hn->hn_aufs_inode->i_sb;
  52         bindex = au_br_index(sb, hinode->hi_id);
  53         br = au_sbr(sb, bindex);
  54         AuDebugOn(!br->br_hfsn);
  55
  56         mark = &hn->hn_mark;
  57         fsnotify_init_mark(mark, au_hfsn_free_mark);
  58         mark->mask = AuHfsnMask;
  59         /*
  60          * by udba rename or rmdir, aufs assign a new inode to the known
  61          * h_inode, so specify 1 to allow dups.
  62          */
  63         lockdep_off();
  64         err = fsnotify_add_mark(mark, br->br_hfsn->hfsn_group, hinode->hi_inode,
  65                                  /*mnt*/NULL, /*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_delayed_kfree(hfsn);
 160 }
 161
 162 static int au_hfsn_handle_event(struct fsnotify_group *group,
 163                                 struct inode *inode,
 164                                 struct fsnotify_mark *inode_mark,
 165                                 struct fsnotify_mark *vfsmount_mark,
 166                                 u32 mask, const void *data, int data_type,
 167                                 const unsigned char *file_name, u32 cookie)
 168 {
 169         int err;
 170         struct au_hnotify *hnotify;
 171         struct inode *h_dir, *h_inode;
 172         struct qstr h_child_qstr = QSTR_INIT(file_name, strlen(file_name));
 173
 174         AuDebugOn(data_type != FSNOTIFY_EVENT_INODE);
 175
 176         err = 0;
 177         /* if FS_UNMOUNT happens, there must be another bug */
 178         AuDebugOn(mask & FS_UNMOUNT);
 179         if (mask & (FS_IN_IGNORED | FS_UNMOUNT))
 180                 goto out;
 181
 182         h_dir = inode;
 183         h_inode = NULL;
 184 #ifdef AuDbgHnotify
 185         au_debug_on();
 186         if (1 || h_child_qstr.len != sizeof(AUFS_XINO_FNAME) - 1
 187             || strncmp(h_child_qstr.name, AUFS_XINO_FNAME, h_child_qstr.len)) {
 188                 AuDbg("i%lu, mask 0x%x %s, hcname %.*s, hi%lu\n",
 189                       h_dir->i_ino, mask, au_hfsn_name(mask),
 190                       AuLNPair(&h_child_qstr), h_inode ? h_inode->i_ino : 0);
 191                 /* WARN_ON(1); */
 192         }
 193         au_debug_off();
 194 #endif
 195
 196         AuDebugOn(!inode_mark);
 197         hnotify = container_of(inode_mark, struct au_hnotify, hn_mark);
 198         err = au_hnotify(h_dir, hnotify, mask, &h_child_qstr, 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 };
 208
 209 /* ---------------------------------------------------------------------- */
 210
 211 static void au_hfsn_fin_br(struct au_branch *br)
 212 {
 213         struct au_br_hfsnotify *hfsn;
 214
 215         hfsn = br->br_hfsn;
 216         if (hfsn) {
 217                 lockdep_off();
 218                 fsnotify_put_group(hfsn->hfsn_group);
 219                 lockdep_on();
 220         }
 221 }
 222
 223 static int au_hfsn_init_br(struct au_branch *br, int perm)
 224 {
 225         int err;
 226         struct fsnotify_group *group;
 227         struct au_br_hfsnotify *hfsn;
 228
 229         err = 0;
 230         br->br_hfsn = NULL;
 231         if (!au_br_hnotifyable(perm))
 232                 goto out;
 233
 234         err = -ENOMEM;
 235         hfsn = kmalloc(sizeof(*hfsn), GFP_NOFS);
 236         if (unlikely(!hfsn))
 237                 goto out;
 238
 239         err = 0;
 240         group = fsnotify_alloc_group(&au_hfsn_ops);
 241         if (IS_ERR(group)) {
 242                 err = PTR_ERR(group);
 243                 pr_err("fsnotify_alloc_group() failed, %d\n", err);
 244                 goto out_hfsn;
 245         }
 246
 247         group->private = hfsn;
 248         hfsn->hfsn_group = group;
 249         br->br_hfsn = hfsn;
 250         goto out; /* success */
 251
 252 out_hfsn:
 253         au_delayed_kfree(hfsn);
 254 out:
 255         return err;
 256 }
 257
 258 static int au_hfsn_reset_br(unsigned int udba, struct au_branch *br, int perm)
 259 {
 260         int err;
 261
 262         err = 0;
 263         if (!br->br_hfsn)
 264                 err = au_hfsn_init_br(br, perm);
 265
 266         return err;
 267 }
 268
 269 /* ---------------------------------------------------------------------- */
 270
 271 static void au_hfsn_fin(void)
 272 {
 273         AuDbg("au_hfsn_ifree %lld\n", (long long)atomic64_read(&au_hfsn_ifree));
 274         wait_event(au_hfsn_wq, !atomic64_read(&au_hfsn_ifree));
 275 }
 276
 277 const struct au_hnotify_op au_hnotify_op = {
 278         .ctl            = au_hfsn_ctl,
 279         .alloc          = au_hfsn_alloc,
 280         .free           = au_hfsn_free,
 281
 282         .fin            = au_hfsn_fin,
 283
 284         .reset_br       = au_hfsn_reset_br,
 285         .fin_br         = au_hfsn_fin_br,
 286         .init_br        = au_hfsn_init_br
 287 };