fs/aufs/sbinfo.c

   1 /*
   2  * Copyright (C) 2005-2017 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  * superblock private data
  20  */
  21
  22 #include "aufs.h"
  23
  24 /*
  25  * they are necessary regardless sysfs is disabled.
  26  */
  27 void au_si_free(struct kobject *kobj)
  28 {
  29         int i;
  30         struct au_sbinfo *sbinfo;
  31         char *locked __maybe_unused; /* debug only */
  32
  33         sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
  34         for (i = 0; i < AuPlink_NHASH; i++)
  35                 AuDebugOn(!hlist_empty(&sbinfo->si_plink[i].head));
  36         AuDebugOn(atomic_read(&sbinfo->si_nowait.nw_len));
  37
  38         AuDebugOn(percpu_counter_sum(&sbinfo->si_ninodes));
  39         percpu_counter_destroy(&sbinfo->si_ninodes);
  40         AuDebugOn(percpu_counter_sum(&sbinfo->si_nfiles));
  41         percpu_counter_destroy(&sbinfo->si_nfiles);
  42
  43         au_rw_write_lock(&sbinfo->si_rwsem);
  44         au_br_free(sbinfo);
  45         au_rw_write_unlock(&sbinfo->si_rwsem);
  46
  47         kfree(sbinfo->si_branch);
  48         mutex_destroy(&sbinfo->si_xib_mtx);
  49         AuRwDestroy(&sbinfo->si_rwsem);
  50
  51         kfree(sbinfo);
  52 }
  53
  54 int au_si_alloc(struct super_block *sb)
  55 {
  56         int err, i;
  57         struct au_sbinfo *sbinfo;
  58
  59         err = -ENOMEM;
  60         sbinfo = kzalloc(sizeof(*sbinfo), GFP_NOFS);
  61         if (unlikely(!sbinfo))
  62                 goto out;
  63
  64         /* will be reallocated separately */
  65         sbinfo->si_branch = kzalloc(sizeof(*sbinfo->si_branch), GFP_NOFS);
  66         if (unlikely(!sbinfo->si_branch))
  67                 goto out_sbinfo;
  68
  69         err = sysaufs_si_init(sbinfo);
  70         if (unlikely(err))
  71                 goto out_br;
  72
  73         au_nwt_init(&sbinfo->si_nowait);
  74         au_rw_init_wlock(&sbinfo->si_rwsem);
  75
  76         percpu_counter_init(&sbinfo->si_ninodes, 0, GFP_NOFS);
  77         percpu_counter_init(&sbinfo->si_nfiles, 0, GFP_NOFS);
  78
  79         sbinfo->si_bbot = -1;
  80         sbinfo->si_last_br_id = AUFS_BRANCH_MAX / 2;
  81
  82         sbinfo->si_wbr_copyup = AuWbrCopyup_Def;
  83         sbinfo->si_wbr_create = AuWbrCreate_Def;
  84         sbinfo->si_wbr_copyup_ops = au_wbr_copyup_ops + sbinfo->si_wbr_copyup;
  85         sbinfo->si_wbr_create_ops = au_wbr_create_ops + sbinfo->si_wbr_create;
  86
  87         au_fhsm_init(sbinfo);
  88
  89         sbinfo->si_mntflags = au_opts_plink(AuOpt_Def);
  90
  91         sbinfo->si_xino_jiffy = jiffies;
  92         sbinfo->si_xino_expire
  93                 = msecs_to_jiffies(AUFS_XINO_DEF_SEC * MSEC_PER_SEC);
  94         mutex_init(&sbinfo->si_xib_mtx);
  95         sbinfo->si_xino_brid = -1;
  96         /* leave si_xib_last_pindex and si_xib_next_bit */
  97
  98         au_sphl_init(&sbinfo->si_aopen);
  99
 100         sbinfo->si_rdcache = msecs_to_jiffies(AUFS_RDCACHE_DEF * MSEC_PER_SEC);
 101         sbinfo->si_rdblk = AUFS_RDBLK_DEF;
 102         sbinfo->si_rdhash = AUFS_RDHASH_DEF;
 103         sbinfo->si_dirwh = AUFS_DIRWH_DEF;
 104
 105         for (i = 0; i < AuPlink_NHASH; i++)
 106                 au_sphl_init(sbinfo->si_plink + i);
 107         init_waitqueue_head(&sbinfo->si_plink_wq);
 108         spin_lock_init(&sbinfo->si_plink_maint_lock);
 109
 110         au_sphl_init(&sbinfo->si_files);
 111
 112         /* with getattr by default */
 113         sbinfo->si_iop_array = aufs_iop;
 114
 115         /* leave other members for sysaufs and si_mnt. */
 116         sbinfo->si_sb = sb;
 117         sb->s_fs_info = sbinfo;
 118         si_pid_set(sb);
 119         return 0; /* success */
 120
 121 out_br:
 122         kfree(sbinfo->si_branch);
 123 out_sbinfo:
 124         kfree(sbinfo);
 125 out:
 126         return err;
 127 }
 128
 129 int au_sbr_realloc(struct au_sbinfo *sbinfo, int nbr, int may_shrink)
 130 {
 131         int err, sz;
 132         struct au_branch **brp;
 133
 134         AuRwMustWriteLock(&sbinfo->si_rwsem);
 135
 136         err = -ENOMEM;
 137         sz = sizeof(*brp) * (sbinfo->si_bbot + 1);
 138         if (unlikely(!sz))
 139                 sz = sizeof(*brp);
 140         brp = au_kzrealloc(sbinfo->si_branch, sz, sizeof(*brp) * nbr, GFP_NOFS,
 141                            may_shrink);
 142         if (brp) {
 143                 sbinfo->si_branch = brp;
 144                 err = 0;
 145         }
 146
 147         return err;
 148 }
 149
 150 /* ---------------------------------------------------------------------- */
 151
 152 unsigned int au_sigen_inc(struct super_block *sb)
 153 {
 154         unsigned int gen;
 155         struct inode *inode;
 156
 157         SiMustWriteLock(sb);
 158
 159         gen = ++au_sbi(sb)->si_generation;
 160         au_update_digen(sb->s_root);
 161         inode = d_inode(sb->s_root);
 162         au_update_iigen(inode, /*half*/0);
 163         inode->i_version++;
 164         return gen;
 165 }
 166
 167 aufs_bindex_t au_new_br_id(struct super_block *sb)
 168 {
 169         aufs_bindex_t br_id;
 170         int i;
 171         struct au_sbinfo *sbinfo;
 172
 173         SiMustWriteLock(sb);
 174
 175         sbinfo = au_sbi(sb);
 176         for (i = 0; i <= AUFS_BRANCH_MAX; i++) {
 177                 br_id = ++sbinfo->si_last_br_id;
 178                 AuDebugOn(br_id < 0);
 179                 if (br_id && au_br_index(sb, br_id) < 0)
 180                         return br_id;
 181         }
 182
 183         return -1;
 184 }
 185
 186 /* ---------------------------------------------------------------------- */
 187
 188 /* it is ok that new 'nwt' tasks are appended while we are sleeping */
 189 int si_read_lock(struct super_block *sb, int flags)
 190 {
 191         int err;
 192
 193         err = 0;
 194         if (au_ftest_lock(flags, FLUSH))
 195                 au_nwt_flush(&au_sbi(sb)->si_nowait);
 196
 197         si_noflush_read_lock(sb);
 198         err = au_plink_maint(sb, flags);
 199         if (unlikely(err))
 200                 si_read_unlock(sb);
 201
 202         return err;
 203 }
 204
 205 int si_write_lock(struct super_block *sb, int flags)
 206 {
 207         int err;
 208
 209         if (au_ftest_lock(flags, FLUSH))
 210                 au_nwt_flush(&au_sbi(sb)->si_nowait);
 211
 212         si_noflush_write_lock(sb);
 213         err = au_plink_maint(sb, flags);
 214         if (unlikely(err))
 215                 si_write_unlock(sb);
 216
 217         return err;
 218 }
 219
 220 /* dentry and super_block lock. call at entry point */
 221 int aufs_read_lock(struct dentry *dentry, int flags)
 222 {
 223         int err;
 224         struct super_block *sb;
 225
 226         sb = dentry->d_sb;
 227         err = si_read_lock(sb, flags);
 228         if (unlikely(err))
 229                 goto out;
 230
 231         if (au_ftest_lock(flags, DW))
 232                 di_write_lock_child(dentry);
 233         else
 234                 di_read_lock_child(dentry, flags);
 235
 236         if (au_ftest_lock(flags, GEN)) {
 237                 err = au_digen_test(dentry, au_sigen(sb));
 238                 if (!au_opt_test(au_mntflags(sb), UDBA_NONE))
 239                         AuDebugOn(!err && au_dbrange_test(dentry));
 240                 else if (!err)
 241                         err = au_dbrange_test(dentry);
 242                 if (unlikely(err))
 243                         aufs_read_unlock(dentry, flags);
 244         }
 245
 246 out:
 247         return err;
 248 }
 249
 250 void aufs_read_unlock(struct dentry *dentry, int flags)
 251 {
 252         if (au_ftest_lock(flags, DW))
 253                 di_write_unlock(dentry);
 254         else
 255                 di_read_unlock(dentry, flags);
 256         si_read_unlock(dentry->d_sb);
 257 }
 258
 259 void aufs_write_lock(struct dentry *dentry)
 260 {
 261         si_write_lock(dentry->d_sb, AuLock_FLUSH | AuLock_NOPLMW);
 262         di_write_lock_child(dentry);
 263 }
 264
 265 void aufs_write_unlock(struct dentry *dentry)
 266 {
 267         di_write_unlock(dentry);
 268         si_write_unlock(dentry->d_sb);
 269 }
 270
 271 int aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int flags)
 272 {
 273         int err;
 274         unsigned int sigen;
 275         struct super_block *sb;
 276
 277         sb = d1->d_sb;
 278         err = si_read_lock(sb, flags);
 279         if (unlikely(err))
 280                 goto out;
 281
 282         di_write_lock2_child(d1, d2, au_ftest_lock(flags, DIRS));
 283
 284         if (au_ftest_lock(flags, GEN)) {
 285                 sigen = au_sigen(sb);
 286                 err = au_digen_test(d1, sigen);
 287                 AuDebugOn(!err && au_dbrange_test(d1));
 288                 if (!err) {
 289                         err = au_digen_test(d2, sigen);
 290                         AuDebugOn(!err && au_dbrange_test(d2));
 291                 }
 292                 if (unlikely(err))
 293                         aufs_read_and_write_unlock2(d1, d2);
 294         }
 295
 296 out:
 297         return err;
 298 }
 299
 300 void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2)
 301 {
 302         di_write_unlock2(d1, d2);
 303         si_read_unlock(d1->d_sb);
 304 }