1d6910058SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later 2ebc921caSIan Kent /* 3ebc921caSIan Kent * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved 4ebc921caSIan Kent * Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org> 5ebc921caSIan Kent * Copyright 2001-2006 Ian Kent <raven@themaw.net> 6ebc921caSIan Kent */ 7ebc921caSIan Kent 8ebc921caSIan Kent #include "autofs_i.h" 9ebc921caSIan Kent 10ebc921caSIan Kent /* Check if a dentry can be expired */ 11ebc921caSIan Kent static inline int autofs_can_expire(struct dentry *dentry, 12e5c85e1fSIan Kent unsigned long timeout, unsigned int how) 13ebc921caSIan Kent { 14ebc921caSIan Kent struct autofs_info *ino = autofs_dentry_ino(dentry); 15ebc921caSIan Kent 16ebc921caSIan Kent /* dentry in the process of being deleted */ 17ebc921caSIan Kent if (ino == NULL) 18ebc921caSIan Kent return 0; 19ebc921caSIan Kent 20e5c85e1fSIan Kent if (!(how & AUTOFS_EXP_IMMEDIATE)) { 21ebc921caSIan Kent /* Too young to die */ 222fd9944fSIan Kent if (!timeout || time_after(ino->last_used + timeout, jiffies)) 23ebc921caSIan Kent return 0; 24ebc921caSIan Kent } 25ebc921caSIan Kent return 1; 26ebc921caSIan Kent } 27ebc921caSIan Kent 28ebc921caSIan Kent /* Check a mount point for busyness */ 29cbf6898fSIan Kent static int autofs_mount_busy(struct vfsmount *mnt, 30cbf6898fSIan Kent struct dentry *dentry, unsigned int how) 31ebc921caSIan Kent { 32ebc921caSIan Kent struct dentry *top = dentry; 33ebc921caSIan Kent struct path path = {.mnt = mnt, .dentry = dentry}; 34ebc921caSIan Kent int status = 1; 35ebc921caSIan Kent 36ebc921caSIan Kent pr_debug("dentry %p %pd\n", dentry, dentry); 37ebc921caSIan Kent 38ebc921caSIan Kent path_get(&path); 39ebc921caSIan Kent 40ebc921caSIan Kent if (!follow_down_one(&path)) 41ebc921caSIan Kent goto done; 42ebc921caSIan Kent 43ebc921caSIan Kent if (is_autofs_dentry(path.dentry)) { 44ebc921caSIan Kent struct autofs_sb_info *sbi = autofs_sbi(path.dentry->d_sb); 45ebc921caSIan Kent 46ebc921caSIan Kent /* This is an autofs submount, we can't expire it */ 47ebc921caSIan Kent if (autofs_type_indirect(sbi->type)) 48ebc921caSIan Kent goto done; 49ebc921caSIan Kent } 50ebc921caSIan Kent 51cbf6898fSIan Kent /* Not a submount, has a forced expire been requested */ 52cbf6898fSIan Kent if (how & AUTOFS_EXP_FORCED) { 53cbf6898fSIan Kent status = 0; 54cbf6898fSIan Kent goto done; 55cbf6898fSIan Kent } 56cbf6898fSIan Kent 57ebc921caSIan Kent /* Update the expiry counter if fs is busy */ 58ebc921caSIan Kent if (!may_umount_tree(path.mnt)) { 59ebc921caSIan Kent struct autofs_info *ino; 60ebc921caSIan Kent 61ebc921caSIan Kent ino = autofs_dentry_ino(top); 62ebc921caSIan Kent ino->last_used = jiffies; 63ebc921caSIan Kent goto done; 64ebc921caSIan Kent } 65ebc921caSIan Kent 66ebc921caSIan Kent status = 0; 67ebc921caSIan Kent done: 68ebc921caSIan Kent pr_debug("returning = %d\n", status); 69ebc921caSIan Kent path_put(&path); 70ebc921caSIan Kent return status; 71ebc921caSIan Kent } 72ebc921caSIan Kent 73ff09297eSAl Viro /* p->d_lock held */ 74ff09297eSAl Viro static struct dentry *positive_after(struct dentry *p, struct dentry *child) 75ff09297eSAl Viro { 76ff09297eSAl Viro if (child) 77ff09297eSAl Viro child = list_next_entry(child, d_child); 78ff09297eSAl Viro else 79ff09297eSAl Viro child = list_first_entry(&p->d_subdirs, struct dentry, d_child); 80ff09297eSAl Viro 81ff09297eSAl Viro list_for_each_entry_from(child, &p->d_subdirs, d_child) { 82ff09297eSAl Viro spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); 83ff09297eSAl Viro if (simple_positive(child)) { 84ff09297eSAl Viro dget_dlock(child); 85ff09297eSAl Viro spin_unlock(&child->d_lock); 86ff09297eSAl Viro return child; 87ff09297eSAl Viro } 88ff09297eSAl Viro spin_unlock(&child->d_lock); 89ff09297eSAl Viro } 90ff09297eSAl Viro 91ff09297eSAl Viro return NULL; 92ff09297eSAl Viro } 93ff09297eSAl Viro 94ebc921caSIan Kent /* 95ebc921caSIan Kent * Calculate and dget next entry in the subdirs list under root. 96ebc921caSIan Kent */ 97ebc921caSIan Kent static struct dentry *get_next_positive_subdir(struct dentry *prev, 98ebc921caSIan Kent struct dentry *root) 99ebc921caSIan Kent { 100ebc921caSIan Kent struct autofs_sb_info *sbi = autofs_sbi(root->d_sb); 101ebc921caSIan Kent struct dentry *q; 102ebc921caSIan Kent 103ebc921caSIan Kent spin_lock(&sbi->lookup_lock); 104ebc921caSIan Kent spin_lock(&root->d_lock); 105ff09297eSAl Viro q = positive_after(root, prev); 106ebc921caSIan Kent spin_unlock(&root->d_lock); 107ebc921caSIan Kent spin_unlock(&sbi->lookup_lock); 108ebc921caSIan Kent dput(prev); 109ebc921caSIan Kent return q; 110ebc921caSIan Kent } 111ebc921caSIan Kent 112ebc921caSIan Kent /* 113ebc921caSIan Kent * Calculate and dget next entry in top down tree traversal. 114ebc921caSIan Kent */ 115ebc921caSIan Kent static struct dentry *get_next_positive_dentry(struct dentry *prev, 116ebc921caSIan Kent struct dentry *root) 117ebc921caSIan Kent { 118ebc921caSIan Kent struct autofs_sb_info *sbi = autofs_sbi(root->d_sb); 119ff09297eSAl Viro struct dentry *p = prev, *ret = NULL, *d = NULL; 120ebc921caSIan Kent 121ebc921caSIan Kent if (prev == NULL) 122ebc921caSIan Kent return dget(root); 123ebc921caSIan Kent 124ebc921caSIan Kent spin_lock(&sbi->lookup_lock); 125ebc921caSIan Kent spin_lock(&p->d_lock); 126ebc921caSIan Kent while (1) { 127ebc921caSIan Kent struct dentry *parent; 128ebc921caSIan Kent 129ff09297eSAl Viro ret = positive_after(p, d); 130ff09297eSAl Viro if (ret || p == root) 131ebc921caSIan Kent break; 132ff09297eSAl Viro parent = p->d_parent; 133ebc921caSIan Kent spin_unlock(&p->d_lock); 134ff09297eSAl Viro spin_lock(&parent->d_lock); 135ff09297eSAl Viro d = p; 136ff09297eSAl Viro p = parent; 137ebc921caSIan Kent } 138ebc921caSIan Kent spin_unlock(&p->d_lock); 139ebc921caSIan Kent spin_unlock(&sbi->lookup_lock); 140ebc921caSIan Kent dput(prev); 141ebc921caSIan Kent return ret; 142ebc921caSIan Kent } 143ebc921caSIan Kent 144ebc921caSIan Kent /* 145ebc921caSIan Kent * Check a direct mount point for busyness. 146ebc921caSIan Kent * Direct mounts have similar expiry semantics to tree mounts. 147ebc921caSIan Kent * The tree is not busy iff no mountpoints are busy and there are no 148ebc921caSIan Kent * autofs submounts. 149ebc921caSIan Kent */ 150ebc921caSIan Kent static int autofs_direct_busy(struct vfsmount *mnt, 151ebc921caSIan Kent struct dentry *top, 152ebc921caSIan Kent unsigned long timeout, 153e5c85e1fSIan Kent unsigned int how) 154ebc921caSIan Kent { 155ebc921caSIan Kent pr_debug("top %p %pd\n", top, top); 156ebc921caSIan Kent 157cbf6898fSIan Kent /* Forced expire, user space handles busy mounts */ 158cbf6898fSIan Kent if (how & AUTOFS_EXP_FORCED) 159cbf6898fSIan Kent return 0; 160cbf6898fSIan Kent 161ebc921caSIan Kent /* If it's busy update the expiry counters */ 162ebc921caSIan Kent if (!may_umount_tree(mnt)) { 163ebc921caSIan Kent struct autofs_info *ino; 164ebc921caSIan Kent 165ebc921caSIan Kent ino = autofs_dentry_ino(top); 166ebc921caSIan Kent if (ino) 167ebc921caSIan Kent ino->last_used = jiffies; 168ebc921caSIan Kent return 1; 169ebc921caSIan Kent } 170ebc921caSIan Kent 171ebc921caSIan Kent /* Timeout of a direct mount is determined by its top dentry */ 172e5c85e1fSIan Kent if (!autofs_can_expire(top, timeout, how)) 173ebc921caSIan Kent return 1; 174ebc921caSIan Kent 175ebc921caSIan Kent return 0; 176ebc921caSIan Kent } 177ebc921caSIan Kent 178ebc921caSIan Kent /* 179ebc921caSIan Kent * Check a directory tree of mount points for busyness 180ebc921caSIan Kent * The tree is not busy iff no mountpoints are busy 181ebc921caSIan Kent */ 182ebc921caSIan Kent static int autofs_tree_busy(struct vfsmount *mnt, 183ebc921caSIan Kent struct dentry *top, 184ebc921caSIan Kent unsigned long timeout, 185e5c85e1fSIan Kent unsigned int how) 186ebc921caSIan Kent { 187ebc921caSIan Kent struct autofs_info *top_ino = autofs_dentry_ino(top); 188ebc921caSIan Kent struct dentry *p; 189ebc921caSIan Kent 190ebc921caSIan Kent pr_debug("top %p %pd\n", top, top); 191ebc921caSIan Kent 192ebc921caSIan Kent /* Negative dentry - give up */ 193ebc921caSIan Kent if (!simple_positive(top)) 194ebc921caSIan Kent return 1; 195ebc921caSIan Kent 196ebc921caSIan Kent p = NULL; 197ebc921caSIan Kent while ((p = get_next_positive_dentry(p, top))) { 198ebc921caSIan Kent pr_debug("dentry %p %pd\n", p, p); 199ebc921caSIan Kent 200ebc921caSIan Kent /* 201ebc921caSIan Kent * Is someone visiting anywhere in the subtree ? 202ebc921caSIan Kent * If there's no mount we need to check the usage 203ebc921caSIan Kent * count for the autofs dentry. 204ebc921caSIan Kent * If the fs is busy update the expiry counter. 205ebc921caSIan Kent */ 206ebc921caSIan Kent if (d_mountpoint(p)) { 207cbf6898fSIan Kent if (autofs_mount_busy(mnt, p, how)) { 208ebc921caSIan Kent top_ino->last_used = jiffies; 209ebc921caSIan Kent dput(p); 210ebc921caSIan Kent return 1; 211ebc921caSIan Kent } 212ebc921caSIan Kent } else { 213ebc921caSIan Kent struct autofs_info *ino = autofs_dentry_ino(p); 214850d71acSAl Viro unsigned int ino_count = READ_ONCE(ino->count); 215ebc921caSIan Kent 216ebc921caSIan Kent /* allow for dget above and top is already dgot */ 217ebc921caSIan Kent if (p == top) 218ebc921caSIan Kent ino_count += 2; 219ebc921caSIan Kent else 220ebc921caSIan Kent ino_count++; 221ebc921caSIan Kent 222ebc921caSIan Kent if (d_count(p) > ino_count) { 223ebc921caSIan Kent top_ino->last_used = jiffies; 224ebc921caSIan Kent dput(p); 225ebc921caSIan Kent return 1; 226ebc921caSIan Kent } 227ebc921caSIan Kent } 228ebc921caSIan Kent } 229ebc921caSIan Kent 230cbf6898fSIan Kent /* Forced expire, user space handles busy mounts */ 231cbf6898fSIan Kent if (how & AUTOFS_EXP_FORCED) 232cbf6898fSIan Kent return 0; 233cbf6898fSIan Kent 234ebc921caSIan Kent /* Timeout of a tree mount is ultimately determined by its top dentry */ 235e5c85e1fSIan Kent if (!autofs_can_expire(top, timeout, how)) 236ebc921caSIan Kent return 1; 237ebc921caSIan Kent 238ebc921caSIan Kent return 0; 239ebc921caSIan Kent } 240ebc921caSIan Kent 241ebc921caSIan Kent static struct dentry *autofs_check_leaves(struct vfsmount *mnt, 242ebc921caSIan Kent struct dentry *parent, 243ebc921caSIan Kent unsigned long timeout, 244e5c85e1fSIan Kent unsigned int how) 245ebc921caSIan Kent { 246ebc921caSIan Kent struct dentry *p; 247ebc921caSIan Kent 248ebc921caSIan Kent pr_debug("parent %p %pd\n", parent, parent); 249ebc921caSIan Kent 250ebc921caSIan Kent p = NULL; 251ebc921caSIan Kent while ((p = get_next_positive_dentry(p, parent))) { 252ebc921caSIan Kent pr_debug("dentry %p %pd\n", p, p); 253ebc921caSIan Kent 254ebc921caSIan Kent if (d_mountpoint(p)) { 255ebc921caSIan Kent /* Can we umount this guy */ 256cbf6898fSIan Kent if (autofs_mount_busy(mnt, p, how)) 257ebc921caSIan Kent continue; 258ebc921caSIan Kent 259cbf6898fSIan Kent /* This isn't a submount so if a forced expire 260cbf6898fSIan Kent * has been requested, user space handles busy 261cbf6898fSIan Kent * mounts */ 262cbf6898fSIan Kent if (how & AUTOFS_EXP_FORCED) 263cbf6898fSIan Kent return p; 264cbf6898fSIan Kent 265ebc921caSIan Kent /* Can we expire this guy */ 266e5c85e1fSIan Kent if (autofs_can_expire(p, timeout, how)) 267ebc921caSIan Kent return p; 268ebc921caSIan Kent } 269ebc921caSIan Kent } 270ebc921caSIan Kent return NULL; 271ebc921caSIan Kent } 272ebc921caSIan Kent 273ebc921caSIan Kent /* Check if we can expire a direct mount (possibly a tree) */ 2745d30517dSIan Kent static struct dentry *autofs_expire_direct(struct super_block *sb, 275ebc921caSIan Kent struct vfsmount *mnt, 276ebc921caSIan Kent struct autofs_sb_info *sbi, 277e5c85e1fSIan Kent unsigned int how) 278ebc921caSIan Kent { 279ebc921caSIan Kent struct dentry *root = dget(sb->s_root); 280ebc921caSIan Kent struct autofs_info *ino; 281e5c85e1fSIan Kent unsigned long timeout; 282ebc921caSIan Kent 283ebc921caSIan Kent if (!root) 284ebc921caSIan Kent return NULL; 285ebc921caSIan Kent 286ebc921caSIan Kent timeout = sbi->exp_timeout; 287ebc921caSIan Kent 288e5c85e1fSIan Kent if (!autofs_direct_busy(mnt, root, timeout, how)) { 289ebc921caSIan Kent spin_lock(&sbi->fs_lock); 290ebc921caSIan Kent ino = autofs_dentry_ino(root); 291ebc921caSIan Kent /* No point expiring a pending mount */ 292ebc921caSIan Kent if (ino->flags & AUTOFS_INF_PENDING) { 293ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 294ebc921caSIan Kent goto out; 295ebc921caSIan Kent } 296ebc921caSIan Kent ino->flags |= AUTOFS_INF_WANT_EXPIRE; 297ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 298ebc921caSIan Kent synchronize_rcu(); 299e5c85e1fSIan Kent if (!autofs_direct_busy(mnt, root, timeout, how)) { 300ebc921caSIan Kent spin_lock(&sbi->fs_lock); 301ebc921caSIan Kent ino->flags |= AUTOFS_INF_EXPIRING; 302ebc921caSIan Kent init_completion(&ino->expire_complete); 303ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 304ebc921caSIan Kent return root; 305ebc921caSIan Kent } 306ebc921caSIan Kent spin_lock(&sbi->fs_lock); 307ebc921caSIan Kent ino->flags &= ~AUTOFS_INF_WANT_EXPIRE; 308ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 309ebc921caSIan Kent } 310ebc921caSIan Kent out: 311ebc921caSIan Kent dput(root); 312ebc921caSIan Kent 313ebc921caSIan Kent return NULL; 314ebc921caSIan Kent } 315ebc921caSIan Kent 316ebc921caSIan Kent /* Check if 'dentry' should expire, or return a nearby 317ebc921caSIan Kent * dentry that is suitable. 318ebc921caSIan Kent * If returned dentry is different from arg dentry, 319ebc921caSIan Kent * then a dget() reference was taken, else not. 320ebc921caSIan Kent */ 321ebc921caSIan Kent static struct dentry *should_expire(struct dentry *dentry, 322ebc921caSIan Kent struct vfsmount *mnt, 323ebc921caSIan Kent unsigned long timeout, 324e5c85e1fSIan Kent unsigned int how) 325ebc921caSIan Kent { 326ebc921caSIan Kent struct autofs_info *ino = autofs_dentry_ino(dentry); 327ebc921caSIan Kent unsigned int ino_count; 328ebc921caSIan Kent 329ebc921caSIan Kent /* No point expiring a pending mount */ 330ebc921caSIan Kent if (ino->flags & AUTOFS_INF_PENDING) 331ebc921caSIan Kent return NULL; 332ebc921caSIan Kent 333ebc921caSIan Kent /* 334ebc921caSIan Kent * Case 1: (i) indirect mount or top level pseudo direct mount 335ebc921caSIan Kent * (autofs-4.1). 336ebc921caSIan Kent * (ii) indirect mount with offset mount, check the "/" 337ebc921caSIan Kent * offset (autofs-5.0+). 338ebc921caSIan Kent */ 339ebc921caSIan Kent if (d_mountpoint(dentry)) { 340ebc921caSIan Kent pr_debug("checking mountpoint %p %pd\n", dentry, dentry); 341ebc921caSIan Kent 342ebc921caSIan Kent /* Can we umount this guy */ 343cbf6898fSIan Kent if (autofs_mount_busy(mnt, dentry, how)) 344ebc921caSIan Kent return NULL; 345ebc921caSIan Kent 346cbf6898fSIan Kent /* This isn't a submount so if a forced expire 347cbf6898fSIan Kent * has been requested, user space handles busy 348cbf6898fSIan Kent * mounts */ 349cbf6898fSIan Kent if (how & AUTOFS_EXP_FORCED) 350cbf6898fSIan Kent return dentry; 351cbf6898fSIan Kent 352ebc921caSIan Kent /* Can we expire this guy */ 353e5c85e1fSIan Kent if (autofs_can_expire(dentry, timeout, how)) 354ebc921caSIan Kent return dentry; 355ebc921caSIan Kent return NULL; 356ebc921caSIan Kent } 357ebc921caSIan Kent 358*eecf77e0SAl Viro if (d_is_symlink(dentry)) { 359ebc921caSIan Kent pr_debug("checking symlink %p %pd\n", dentry, dentry); 360cbf6898fSIan Kent 361cbf6898fSIan Kent /* Forced expire, user space handles busy mounts */ 362cbf6898fSIan Kent if (how & AUTOFS_EXP_FORCED) 363cbf6898fSIan Kent return dentry; 364cbf6898fSIan Kent 365ebc921caSIan Kent /* 366ebc921caSIan Kent * A symlink can't be "busy" in the usual sense so 367ebc921caSIan Kent * just check last used for expire timeout. 368ebc921caSIan Kent */ 369e5c85e1fSIan Kent if (autofs_can_expire(dentry, timeout, how)) 370ebc921caSIan Kent return dentry; 371ebc921caSIan Kent return NULL; 372ebc921caSIan Kent } 373ebc921caSIan Kent 374ebc921caSIan Kent if (simple_empty(dentry)) 375ebc921caSIan Kent return NULL; 376ebc921caSIan Kent 377ebc921caSIan Kent /* Case 2: tree mount, expire iff entire tree is not busy */ 378e5c85e1fSIan Kent if (!(how & AUTOFS_EXP_LEAVES)) { 379cbf6898fSIan Kent /* Not a forced expire? */ 380cbf6898fSIan Kent if (!(how & AUTOFS_EXP_FORCED)) { 381cbf6898fSIan Kent /* ref-walk currently on this dentry? */ 382850d71acSAl Viro ino_count = READ_ONCE(ino->count) + 1; 383ebc921caSIan Kent if (d_count(dentry) > ino_count) 384ebc921caSIan Kent return NULL; 385cbf6898fSIan Kent } 386ebc921caSIan Kent 387e5c85e1fSIan Kent if (!autofs_tree_busy(mnt, dentry, timeout, how)) 388ebc921caSIan Kent return dentry; 389ebc921caSIan Kent /* 390ebc921caSIan Kent * Case 3: pseudo direct mount, expire individual leaves 391ebc921caSIan Kent * (autofs-4.1). 392ebc921caSIan Kent */ 393ebc921caSIan Kent } else { 394ebc921caSIan Kent struct dentry *expired; 395ebc921caSIan Kent 396cbf6898fSIan Kent /* Not a forced expire? */ 397cbf6898fSIan Kent if (!(how & AUTOFS_EXP_FORCED)) { 398cbf6898fSIan Kent /* ref-walk currently on this dentry? */ 399850d71acSAl Viro ino_count = READ_ONCE(ino->count) + 1; 400ebc921caSIan Kent if (d_count(dentry) > ino_count) 401ebc921caSIan Kent return NULL; 402cbf6898fSIan Kent } 403ebc921caSIan Kent 404e5c85e1fSIan Kent expired = autofs_check_leaves(mnt, dentry, timeout, how); 405ebc921caSIan Kent if (expired) { 406ebc921caSIan Kent if (expired == dentry) 407ebc921caSIan Kent dput(dentry); 408ebc921caSIan Kent return expired; 409ebc921caSIan Kent } 410ebc921caSIan Kent } 411ebc921caSIan Kent return NULL; 412ebc921caSIan Kent } 413ebc921caSIan Kent 414ebc921caSIan Kent /* 415ebc921caSIan Kent * Find an eligible tree to time-out 416ebc921caSIan Kent * A tree is eligible if :- 417ebc921caSIan Kent * - it is unused by any user process 418ebc921caSIan Kent * - it has been unused for exp_timeout time 419ebc921caSIan Kent */ 420571bc35cSIan Kent static struct dentry *autofs_expire_indirect(struct super_block *sb, 421ebc921caSIan Kent struct vfsmount *mnt, 422ebc921caSIan Kent struct autofs_sb_info *sbi, 423e5c85e1fSIan Kent unsigned int how) 424ebc921caSIan Kent { 425ebc921caSIan Kent unsigned long timeout; 426ebc921caSIan Kent struct dentry *root = sb->s_root; 427ebc921caSIan Kent struct dentry *dentry; 428ebc921caSIan Kent struct dentry *expired; 429ebc921caSIan Kent struct dentry *found; 430ebc921caSIan Kent struct autofs_info *ino; 431ebc921caSIan Kent 432ebc921caSIan Kent if (!root) 433ebc921caSIan Kent return NULL; 434ebc921caSIan Kent 435ebc921caSIan Kent timeout = sbi->exp_timeout; 436ebc921caSIan Kent 437ebc921caSIan Kent dentry = NULL; 438ebc921caSIan Kent while ((dentry = get_next_positive_subdir(dentry, root))) { 439ebc921caSIan Kent spin_lock(&sbi->fs_lock); 440ebc921caSIan Kent ino = autofs_dentry_ino(dentry); 441ebc921caSIan Kent if (ino->flags & AUTOFS_INF_WANT_EXPIRE) { 442ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 443ebc921caSIan Kent continue; 444ebc921caSIan Kent } 445ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 446ebc921caSIan Kent 447e5c85e1fSIan Kent expired = should_expire(dentry, mnt, timeout, how); 448ebc921caSIan Kent if (!expired) 449ebc921caSIan Kent continue; 450ebc921caSIan Kent 451ebc921caSIan Kent spin_lock(&sbi->fs_lock); 452ebc921caSIan Kent ino = autofs_dentry_ino(expired); 453ebc921caSIan Kent ino->flags |= AUTOFS_INF_WANT_EXPIRE; 454ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 455ebc921caSIan Kent synchronize_rcu(); 456ebc921caSIan Kent 457ebc921caSIan Kent /* Make sure a reference is not taken on found if 458ebc921caSIan Kent * things have changed. 459ebc921caSIan Kent */ 460e5c85e1fSIan Kent how &= ~AUTOFS_EXP_LEAVES; 461e5c85e1fSIan Kent found = should_expire(expired, mnt, timeout, how); 46203ad0d70SAl Viro if (found != expired) { // something has changed, continue 46303ad0d70SAl Viro dput(found); 464ebc921caSIan Kent goto next; 46503ad0d70SAl Viro } 466ebc921caSIan Kent 467ebc921caSIan Kent if (expired != dentry) 468ebc921caSIan Kent dput(dentry); 469ebc921caSIan Kent 470ebc921caSIan Kent spin_lock(&sbi->fs_lock); 471ebc921caSIan Kent goto found; 472ebc921caSIan Kent next: 473ebc921caSIan Kent spin_lock(&sbi->fs_lock); 474ebc921caSIan Kent ino->flags &= ~AUTOFS_INF_WANT_EXPIRE; 475ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 476ebc921caSIan Kent if (expired != dentry) 477ebc921caSIan Kent dput(expired); 478ebc921caSIan Kent } 479ebc921caSIan Kent return NULL; 480ebc921caSIan Kent 481ebc921caSIan Kent found: 482ebc921caSIan Kent pr_debug("returning %p %pd\n", expired, expired); 483ebc921caSIan Kent ino->flags |= AUTOFS_INF_EXPIRING; 484ebc921caSIan Kent init_completion(&ino->expire_complete); 485ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 486ebc921caSIan Kent return expired; 487ebc921caSIan Kent } 488ebc921caSIan Kent 489ebc921caSIan Kent int autofs_expire_wait(const struct path *path, int rcu_walk) 490ebc921caSIan Kent { 491ebc921caSIan Kent struct dentry *dentry = path->dentry; 492ebc921caSIan Kent struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 493ebc921caSIan Kent struct autofs_info *ino = autofs_dentry_ino(dentry); 494ebc921caSIan Kent int status; 495ebc921caSIan Kent int state; 496ebc921caSIan Kent 497ebc921caSIan Kent /* Block on any pending expire */ 498ebc921caSIan Kent if (!(ino->flags & AUTOFS_INF_WANT_EXPIRE)) 499ebc921caSIan Kent return 0; 500ebc921caSIan Kent if (rcu_walk) 501ebc921caSIan Kent return -ECHILD; 502ebc921caSIan Kent 503ebc921caSIan Kent retry: 504ebc921caSIan Kent spin_lock(&sbi->fs_lock); 505ebc921caSIan Kent state = ino->flags & (AUTOFS_INF_WANT_EXPIRE | AUTOFS_INF_EXPIRING); 506ebc921caSIan Kent if (state == AUTOFS_INF_WANT_EXPIRE) { 507ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 508ebc921caSIan Kent /* 509ebc921caSIan Kent * Possibly being selected for expire, wait until 510ebc921caSIan Kent * it's selected or not. 511ebc921caSIan Kent */ 512ebc921caSIan Kent schedule_timeout_uninterruptible(HZ/10); 513ebc921caSIan Kent goto retry; 514ebc921caSIan Kent } 515ebc921caSIan Kent if (state & AUTOFS_INF_EXPIRING) { 516ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 517ebc921caSIan Kent 518ebc921caSIan Kent pr_debug("waiting for expire %p name=%pd\n", dentry, dentry); 519ebc921caSIan Kent 520ebc921caSIan Kent status = autofs_wait(sbi, path, NFY_NONE); 521ebc921caSIan Kent wait_for_completion(&ino->expire_complete); 522ebc921caSIan Kent 523ebc921caSIan Kent pr_debug("expire done status=%d\n", status); 524ebc921caSIan Kent 525ebc921caSIan Kent if (d_unhashed(dentry)) 526ebc921caSIan Kent return -EAGAIN; 527ebc921caSIan Kent 528ebc921caSIan Kent return status; 529ebc921caSIan Kent } 530ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 531ebc921caSIan Kent 532ebc921caSIan Kent return 0; 533ebc921caSIan Kent } 534ebc921caSIan Kent 535ebc921caSIan Kent /* Perform an expiry operation */ 536ebc921caSIan Kent int autofs_expire_run(struct super_block *sb, 537ebc921caSIan Kent struct vfsmount *mnt, 538ebc921caSIan Kent struct autofs_sb_info *sbi, 539ebc921caSIan Kent struct autofs_packet_expire __user *pkt_p) 540ebc921caSIan Kent { 541ebc921caSIan Kent struct autofs_packet_expire pkt; 542ebc921caSIan Kent struct autofs_info *ino; 543ebc921caSIan Kent struct dentry *dentry; 544ebc921caSIan Kent int ret = 0; 545ebc921caSIan Kent 546ebc921caSIan Kent memset(&pkt, 0, sizeof(pkt)); 547ebc921caSIan Kent 548ebc921caSIan Kent pkt.hdr.proto_version = sbi->version; 549ebc921caSIan Kent pkt.hdr.type = autofs_ptype_expire; 550ebc921caSIan Kent 551ebc921caSIan Kent dentry = autofs_expire_indirect(sb, mnt, sbi, 0); 552ebc921caSIan Kent if (!dentry) 553ebc921caSIan Kent return -EAGAIN; 554ebc921caSIan Kent 555ebc921caSIan Kent pkt.len = dentry->d_name.len; 556ebc921caSIan Kent memcpy(pkt.name, dentry->d_name.name, pkt.len); 557ebc921caSIan Kent pkt.name[pkt.len] = '\0'; 558ebc921caSIan Kent 559ebc921caSIan Kent if (copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire))) 560ebc921caSIan Kent ret = -EFAULT; 561ebc921caSIan Kent 562ebc921caSIan Kent spin_lock(&sbi->fs_lock); 563ebc921caSIan Kent ino = autofs_dentry_ino(dentry); 564ebc921caSIan Kent /* avoid rapid-fire expire attempts if expiry fails */ 5652fd9944fSIan Kent ino->last_used = jiffies; 566ebc921caSIan Kent ino->flags &= ~(AUTOFS_INF_EXPIRING|AUTOFS_INF_WANT_EXPIRE); 567ebc921caSIan Kent complete_all(&ino->expire_complete); 568ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 569ebc921caSIan Kent 57063ce5f55SPan Bian dput(dentry); 57163ce5f55SPan Bian 572ebc921caSIan Kent return ret; 573ebc921caSIan Kent } 574ebc921caSIan Kent 575ebc921caSIan Kent int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, 576e5c85e1fSIan Kent struct autofs_sb_info *sbi, unsigned int how) 577ebc921caSIan Kent { 578ebc921caSIan Kent struct dentry *dentry; 579ebc921caSIan Kent int ret = -EAGAIN; 580ebc921caSIan Kent 581ebc921caSIan Kent if (autofs_type_trigger(sbi->type)) 582e5c85e1fSIan Kent dentry = autofs_expire_direct(sb, mnt, sbi, how); 583ebc921caSIan Kent else 584e5c85e1fSIan Kent dentry = autofs_expire_indirect(sb, mnt, sbi, how); 585ebc921caSIan Kent 586ebc921caSIan Kent if (dentry) { 587ebc921caSIan Kent struct autofs_info *ino = autofs_dentry_ino(dentry); 588ebc921caSIan Kent const struct path path = { .mnt = mnt, .dentry = dentry }; 589ebc921caSIan Kent 590ebc921caSIan Kent /* This is synchronous because it makes the daemon a 591ebc921caSIan Kent * little easier 592ebc921caSIan Kent */ 593ebc921caSIan Kent ret = autofs_wait(sbi, &path, NFY_EXPIRE); 594ebc921caSIan Kent 595ebc921caSIan Kent spin_lock(&sbi->fs_lock); 596ebc921caSIan Kent /* avoid rapid-fire expire attempts if expiry fails */ 5972fd9944fSIan Kent ino->last_used = jiffies; 598ebc921caSIan Kent ino->flags &= ~(AUTOFS_INF_EXPIRING|AUTOFS_INF_WANT_EXPIRE); 599ebc921caSIan Kent complete_all(&ino->expire_complete); 600ebc921caSIan Kent spin_unlock(&sbi->fs_lock); 601ebc921caSIan Kent dput(dentry); 602ebc921caSIan Kent } 603ebc921caSIan Kent 604ebc921caSIan Kent return ret; 605ebc921caSIan Kent } 606ebc921caSIan Kent 607ebc921caSIan Kent /* 608ebc921caSIan Kent * Call repeatedly until it returns -EAGAIN, meaning there's nothing 609ebc921caSIan Kent * more to be done. 610ebc921caSIan Kent */ 611ebc921caSIan Kent int autofs_expire_multi(struct super_block *sb, struct vfsmount *mnt, 612ebc921caSIan Kent struct autofs_sb_info *sbi, int __user *arg) 613ebc921caSIan Kent { 614e5c85e1fSIan Kent unsigned int how = 0; 615ebc921caSIan Kent 616e5c85e1fSIan Kent if (arg && get_user(how, arg)) 617ebc921caSIan Kent return -EFAULT; 618ebc921caSIan Kent 619e5c85e1fSIan Kent return autofs_do_expire_multi(sb, mnt, sbi, how); 620ebc921caSIan Kent } 621