diff options
Diffstat (limited to 'fs/dcache.c')
-rw-r--r-- | fs/dcache.c | 481 |
1 files changed, 201 insertions, 280 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index ca02c13a84aa..15bc5f602be1 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -44,7 +44,7 @@ /* * Usage: * dcache->d_inode->i_lock protects: - * - i_dentry, d_alias, d_inode of aliases + * - i_dentry, d_u.d_alias, d_inode of aliases * dcache_hash_bucket lock protects: * - the dcache hash table * s_anon bl list spinlock protects: @@ -59,7 +59,7 @@ * - d_unhashed() * - d_parent and d_subdirs * - childrens' d_child and d_parent - * - d_alias, d_inode + * - d_u.d_alias, d_inode * * Ordering: * dentry->d_inode->i_lock @@ -106,8 +106,7 @@ static inline struct hlist_bl_head *d_hash(const struct dentry *parent, unsigned int hash) { hash += (unsigned long) parent / L1_CACHE_BYTES; - hash = hash + (hash >> d_hash_shift); - return dentry_hashtable + (hash & d_hash_mask); + return dentry_hashtable + hash_32(hash, d_hash_shift); } /* Statistics gathering. */ @@ -240,22 +239,13 @@ static void __d_free(struct rcu_head *head) { struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu); - WARN_ON(!hlist_unhashed(&dentry->d_alias)); if (dname_external(dentry)) kfree(dentry->d_name.name); kmem_cache_free(dentry_cache, dentry); } -/* - * no locks, please. - */ -static void d_free(struct dentry *dentry) +static void dentry_free(struct dentry *dentry) { - BUG_ON((int)dentry->d_lockref.count > 0); - this_cpu_dec(nr_dentry); - if (dentry->d_op && dentry->d_op->d_release) - dentry->d_op->d_release(dentry); - /* if dentry was never visible to RCU, immediate free is OK */ if (!(dentry->d_flags & DCACHE_RCUACCESS)) __d_free(&dentry->d_u.d_rcu); @@ -289,7 +279,7 @@ static void dentry_iput(struct dentry * dentry) struct inode *inode = dentry->d_inode; if (inode) { dentry->d_inode = NULL; - hlist_del_init(&dentry->d_alias); + hlist_del_init(&dentry->d_u.d_alias); spin_unlock(&dentry->d_lock); spin_unlock(&inode->i_lock); if (!inode->i_nlink) @@ -314,7 +304,7 @@ static void dentry_unlink_inode(struct dentry * dentry) struct inode *inode = dentry->d_inode; __d_clear_type(dentry); dentry->d_inode = NULL; - hlist_del_init(&dentry->d_alias); + hlist_del_init(&dentry->d_u.d_alias); dentry_rcuwalk_barrier(dentry); spin_unlock(&dentry->d_lock); spin_unlock(&inode->i_lock); @@ -403,56 +393,6 @@ static void dentry_lru_add(struct dentry *dentry) d_lru_add(dentry); } -/* - * Remove a dentry with references from the LRU. - * - * If we are on the shrink list, then we can get to try_prune_one_dentry() and - * lose our last reference through the parent walk. In this case, we need to - * remove ourselves from the shrink list, not the LRU. - */ -static void dentry_lru_del(struct dentry *dentry) -{ - if (dentry->d_flags & DCACHE_LRU_LIST) { - if (dentry->d_flags & DCACHE_SHRINK_LIST) - return d_shrink_del(dentry); - d_lru_del(dentry); - } -} - -/** - * d_kill - kill dentry and return parent - * @dentry: dentry to kill - * @parent: parent dentry - * - * The dentry must already be unhashed and removed from the LRU. - * - * If this is the root of the dentry tree, return NULL. - * - * dentry->d_lock and parent->d_lock must be held by caller, and are dropped by - * d_kill. - */ -static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent) - __releases(dentry->d_lock) - __releases(parent->d_lock) - __releases(dentry->d_inode->i_lock) -{ - list_del(&dentry->d_u.d_child); - /* - * Inform d_walk() that we are no longer attached to the - * dentry tree - */ - dentry->d_flags |= DCACHE_DENTRY_KILLED; - if (parent) - spin_unlock(&parent->d_lock); - dentry_iput(dentry); - /* - * dentry_iput drops the locks, at which point nobody (except - * transient RCU lookups) can reach this dentry. - */ - d_free(dentry); - return parent; -} - /** * d_drop - drop a dentry * @dentry: dentry to drop @@ -510,7 +450,14 @@ dentry_kill(struct dentry *dentry, int unlock_on_failure) __releases(dentry->d_lock) { struct inode *inode; - struct dentry *parent; + struct dentry *parent = NULL; + bool can_free = true; + + if (unlikely(dentry->d_flags & DCACHE_DENTRY_KILLED)) { + can_free = dentry->d_flags & DCACHE_MAY_FREE; + spin_unlock(&dentry->d_lock); + goto out; + } inode = dentry->d_inode; if (inode && !spin_trylock(&inode->i_lock)) { @@ -521,9 +468,7 @@ relock: } return dentry; /* try again with same dentry */ } - if (IS_ROOT(dentry)) - parent = NULL; - else + if (!IS_ROOT(dentry)) parent = dentry->d_parent; if (parent && !spin_trylock(&parent->d_lock)) { if (inode) @@ -543,10 +488,40 @@ relock: if ((dentry->d_flags & DCACHE_OP_PRUNE) && !d_unhashed(dentry)) dentry->d_op->d_prune(dentry); - dentry_lru_del(dentry); + if (dentry->d_flags & DCACHE_LRU_LIST) { + if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) + d_lru_del(dentry); + } /* if it was on the hash then remove it */ __d_drop(dentry); - return d_kill(dentry, parent); + __list_del_entry(&dentry->d_child); + /* + * Inform d_walk() that we are no longer attached to the + * dentry tree + */ + dentry->d_flags |= DCACHE_DENTRY_KILLED; + if (parent) + spin_unlock(&parent->d_lock); + dentry_iput(dentry); + /* + * dentry_iput drops the locks, at which point nobody (except + * transient RCU lookups) can reach this dentry. + */ + BUG_ON((int)dentry->d_lockref.count > 0); + this_cpu_dec(nr_dentry); + if (dentry->d_op && dentry->d_op->d_release) + dentry->d_op->d_release(dentry); + + spin_lock(&dentry->d_lock); + if (dentry->d_flags & DCACHE_SHRINK_LIST) { + dentry->d_flags |= DCACHE_MAY_FREE; + can_free = false; + } + spin_unlock(&dentry->d_lock); +out: + if (likely(can_free)) + dentry_free(dentry); + return parent; } /* @@ -588,6 +563,9 @@ repeat: if (unlikely(d_unhashed(dentry))) goto kill_it; + if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED)) + goto kill_it; + if (unlikely(dentry->d_flags & DCACHE_OP_DELETE)) { if (dentry->d_op->d_delete(dentry)) goto kill_it; @@ -738,7 +716,7 @@ static struct dentry *__d_find_alias(struct inode *inode, int want_discon) again: discon_alias = NULL; - hlist_for_each_entry(alias, &inode->i_dentry, d_alias) { + hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { spin_lock(&alias->d_lock); if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) { if (IS_ROOT(alias) && @@ -791,7 +769,7 @@ void d_prune_aliases(struct inode *inode) struct dentry *dentry; restart: spin_lock(&inode->i_lock); - hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) { + hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) { spin_lock(&dentry->d_lock); if (!dentry->d_lockref.count) { /* @@ -815,65 +793,13 @@ restart: } EXPORT_SYMBOL(d_prune_aliases); -/* - * Try to throw away a dentry - free the inode, dput the parent. - * Requires dentry->d_lock is held, and dentry->d_count == 0. - * Releases dentry->d_lock. - * - * This may fail if locks cannot be acquired no problem, just try again. - */ -static struct dentry * try_prune_one_dentry(struct dentry *dentry) - __releases(dentry->d_lock) -{ - struct dentry *parent; - - parent = dentry_kill(dentry, 0); - /* - * If dentry_kill returns NULL, we have nothing more to do. - * if it returns the same dentry, trylocks failed. In either - * case, just loop again. - * - * Otherwise, we need to prune ancestors too. This is necessary - * to prevent quadratic behavior of shrink_dcache_parent(), but - * is also expected to be beneficial in reducing dentry cache - * fragmentation. - */ - if (!parent) - return NULL; - if (parent == dentry) - return dentry; - - /* Prune ancestors. */ - dentry = parent; - while (dentry) { - if (lockref_put_or_lock(&dentry->d_lockref)) - return NULL; - dentry = dentry_kill(dentry, 1); - } - return NULL; -} - static void shrink_dentry_list(struct list_head *list) { - struct dentry *dentry; - - rcu_read_lock(); - for (;;) { - dentry = list_entry_rcu(list->prev, struct dentry, d_lru); - if (&dentry->d_lru == list) - break; /* empty */ + struct dentry *dentry, *parent; - /* - * Get the dentry lock, and re-verify that the dentry is - * this on the shrinking list. If it is, we know that - * DCACHE_SHRINK_LIST and DCACHE_LRU_LIST are set. - */ + while (!list_empty(list)) { + dentry = list_entry(list->prev, struct dentry, d_lru); spin_lock(&dentry->d_lock); - if (dentry != list_entry(list->prev, struct dentry, d_lru)) { - spin_unlock(&dentry->d_lock); - continue; - } - /* * The dispose list is isolated and dentries are not accounted * to the LRU here, so we can simply remove it from the list @@ -885,30 +811,38 @@ static void shrink_dentry_list(struct list_head *list) * We found an inuse dentry which was not removed from * the LRU because of laziness during lookup. Do not free it. */ - if (dentry->d_lockref.count) { + if ((int)dentry->d_lockref.count > 0) { spin_unlock(&dentry->d_lock); continue; } - rcu_read_unlock(); + parent = dentry_kill(dentry, 0); /* - * If 'try_to_prune()' returns a dentry, it will - * be the same one we passed in, and d_lock will - * have been held the whole time, so it will not - * have been added to any other lists. We failed - * to get the inode lock. - * - * We just add it back to the shrink list. + * If dentry_kill returns NULL, we have nothing more to do. */ - dentry = try_prune_one_dentry(dentry); + if (!parent) + continue; - rcu_read_lock(); - if (dentry) { + if (unlikely(parent == dentry)) { + /* + * trylocks have failed and d_lock has been held the + * whole time, so it could not have been added to any + * other lists. Just add it back to the shrink list. + */ d_shrink_add(dentry, list); spin_unlock(&dentry->d_lock); + continue; } + /* + * We need to prune ancestors too. This is necessary to prevent + * quadratic behavior of shrink_dcache_parent(), but is also + * expected to be beneficial in reducing dentry cache + * fragmentation. + */ + dentry = parent; + while (dentry && !lockref_put_or_lock(&dentry->d_lockref)) + dentry = dentry_kill(dentry, 1); } - rcu_read_unlock(); } static enum lru_status @@ -1092,7 +1026,7 @@ repeat: resume: while (next != &this_parent->d_subdirs) { struct list_head *tmp = next; - struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); + struct dentry *dentry = list_entry(tmp, struct dentry, d_child); next = tmp->next; spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); @@ -1124,33 +1058,31 @@ resume: /* * All done at this level ... ascend and resume the search. */ + rcu_read_lock(); +ascend: if (this_parent != parent) { struct dentry *child = this_parent; this_parent = child->d_parent; - rcu_read_lock(); spin_unlock(&child->d_lock); spin_lock(&this_parent->d_lock); - /* - * might go back up the wrong parent if we have had a rename - * or deletion - */ - if (this_parent != child->d_parent || - (child->d_flags & DCACHE_DENTRY_KILLED) || - need_seqretry(&rename_lock, seq)) { - spin_unlock(&this_parent->d_lock); - rcu_read_unlock(); + /* might go back up the wrong parent if we have had a rename. */ + if (need_seqretry(&rename_lock, seq)) goto rename_retry; - } + /* go into the first sibling still alive */ + do { + next = child->d_child.next; + if (next == &this_parent->d_subdirs) + goto ascend; + child = list_entry(next, struct dentry, d_child); + } while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED)); rcu_read_unlock(); - next = child->d_u.d_child.next; goto resume; } - if (need_seqretry(&rename_lock, seq)) { - spin_unlock(&this_parent->d_lock); + if (need_seqretry(&rename_lock, seq)) goto rename_retry; - } + rcu_read_unlock(); if (finish) finish(data); @@ -1160,6 +1092,9 @@ out_unlock: return; rename_retry: + spin_unlock(&this_parent->d_lock); + rcu_read_unlock(); + BUG_ON(seq & 1); if (!retry) return; seq = 1; @@ -1261,34 +1196,23 @@ static enum d_walk_ret select_collect(void *_data, struct dentry *dentry) if (data->start == dentry) goto out; - /* - * move only zero ref count dentries to the dispose list. - * - * Those which are presently on the shrink list, being processed - * by shrink_dentry_list(), shouldn't be moved. Otherwise the - * loop in shrink_dcache_parent() might not make any progress - * and loop forever. - */ - if (dentry->d_lockref.count) { - dentry_lru_del(dentry); - } else if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) { - /* - * We can't use d_lru_shrink_move() because we - * need to get the global LRU lock and do the - * LRU accounting. - */ - d_lru_del(dentry); - d_shrink_add(dentry, &data->dispose); + if (dentry->d_flags & DCACHE_SHRINK_LIST) { data->found++; - ret = D_WALK_NORETRY; + } else { + if (dentry->d_flags & DCACHE_LRU_LIST) + d_lru_del(dentry); + if (!dentry->d_lockref.count) { + d_shrink_add(dentry, &data->dispose); + data->found++; + } } /* * We can return to the caller if we have found some (this * ensures forward progress). We'll be coming back to find * the rest. */ - if (data->found && need_resched()) - ret = D_WALK_QUIT; + if (!list_empty(&data->dispose)) + ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY; out: return ret; } @@ -1318,45 +1242,35 @@ void shrink_dcache_parent(struct dentry *parent) } EXPORT_SYMBOL(shrink_dcache_parent); -static enum d_walk_ret umount_collect(void *_data, struct dentry *dentry) +static enum d_walk_ret umount_check(void *_data, struct dentry *dentry) { - struct select_data *data = _data; - enum d_walk_ret ret = D_WALK_CONTINUE; + /* it has busy descendents; complain about those instead */ + if (!list_empty(&dentry->d_subdirs)) + return D_WALK_CONTINUE; - if (dentry->d_lockref.count) { - dentry_lru_del(dentry); - if (likely(!list_empty(&dentry->d_subdirs))) - goto out; - if (dentry == data->start && dentry->d_lockref.count == 1) - goto out; - printk(KERN_ERR - "BUG: Dentry %p{i=%lx,n=%s}" - " still in use (%d)" - " [unmount of %s %s]\n", + /* root with refcount 1 is fine */ + if (dentry == _data && dentry->d_lockref.count == 1) + return D_WALK_CONTINUE; + + printk(KERN_ERR "BUG: Dentry %p{i=%lx,n=%pd} " + " still in use (%d) [unmount of %s %s]\n", dentry, dentry->d_inode ? dentry->d_inode->i_ino : 0UL, - dentry->d_name.name, + dentry, dentry->d_lockref.count, dentry->d_sb->s_type->name, dentry->d_sb->s_id); - BUG(); - } else if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) { - /* - * We can't use d_lru_shrink_move() because we - * need to get the global LRU lock and do the - * LRU accounting. - */ - if (dentry->d_flags & DCACHE_LRU_LIST) - d_lru_del(dentry); - d_shrink_add(dentry, &data->dispose); - data->found++; - ret = D_WALK_NORETRY; - } -out: - if (data->found && need_resched()) - ret = D_WALK_QUIT; - return ret; + WARN_ON(1); + return D_WALK_CONTINUE; +} + +static void do_one_tree(struct dentry *dentry) +{ + shrink_dcache_parent(dentry); + d_walk(dentry, dentry, umount_check, NULL); + d_drop(dentry); + dput(dentry); } /* @@ -1366,40 +1280,15 @@ void shrink_dcache_for_umount(struct super_block *sb) { struct dentry *dentry; - if (down_read_trylock(&sb->s_umount)) - BUG(); + WARN(down_read_trylock(&sb->s_umount), "s_umount should've been locked"); dentry = sb->s_root; sb->s_root = NULL; - for (;;) { - struct select_data data; - - INIT_LIST_HEAD(&data.dispose); - data.start = dentry; - data.found = 0; - - d_walk(dentry, &data, umount_collect, NULL); - if (!data.found) - break; - - shrink_dentry_list(&data.dispose); - cond_resched(); - } - d_drop(dentry); - dput(dentry); + do_one_tree(dentry); while (!hlist_bl_empty(&sb->s_anon)) { - struct select_data data; - dentry = hlist_bl_entry(hlist_bl_first(&sb->s_anon), struct dentry, d_hash); - - INIT_LIST_HEAD(&data.dispose); - data.start = NULL; - data.found = 0; - - d_walk(dentry, &data, umount_collect, NULL); - if (data.found) - shrink_dentry_list(&data.dispose); - cond_resched(); + dentry = dget(hlist_bl_entry(hlist_bl_first(&sb->s_anon), struct dentry, d_hash)); + do_one_tree(dentry); } } @@ -1525,8 +1414,8 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) INIT_HLIST_BL_NODE(&dentry->d_hash); INIT_LIST_HEAD(&dentry->d_lru); INIT_LIST_HEAD(&dentry->d_subdirs); - INIT_HLIST_NODE(&dentry->d_alias); - INIT_LIST_HEAD(&dentry->d_u.d_child); + INIT_HLIST_NODE(&dentry->d_u.d_alias); + INIT_LIST_HEAD(&dentry->d_child); d_set_d_op(dentry, dentry->d_sb->s_d_op); this_cpu_inc(nr_dentry); @@ -1556,7 +1445,7 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name) */ __dget_dlock(parent); dentry->d_parent = parent; - list_add(&dentry->d_u.d_child, &parent->d_subdirs); + list_add(&dentry->d_child, &parent->d_subdirs); spin_unlock(&parent->d_lock); return dentry; @@ -1647,10 +1536,9 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode) unsigned add_flags = d_flags_for_inode(inode); spin_lock(&dentry->d_lock); - dentry->d_flags &= ~DCACHE_ENTRY_TYPE; - dentry->d_flags |= add_flags; + __d_set_type(dentry, add_flags); if (inode) - hlist_add_head(&dentry->d_alias, &inode->i_dentry); + hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry); dentry->d_inode = inode; dentry_rcuwalk_barrier(dentry); spin_unlock(&dentry->d_lock); @@ -1674,7 +1562,7 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode) void d_instantiate(struct dentry *entry, struct inode * inode) { - BUG_ON(!hlist_unhashed(&entry->d_alias)); + BUG_ON(!hlist_unhashed(&entry->d_u.d_alias)); if (inode) spin_lock(&inode->i_lock); __d_instantiate(entry, inode); @@ -1713,7 +1601,7 @@ static struct dentry *__d_instantiate_unique(struct dentry *entry, return NULL; } - hlist_for_each_entry(alias, &inode->i_dentry, d_alias) { + hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { /* * Don't need alias->d_lock here, because aliases with * d_parent == entry->d_parent are not subject to name or @@ -1739,7 +1627,7 @@ struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode) { struct dentry *result; - BUG_ON(!hlist_unhashed(&entry->d_alias)); + BUG_ON(!hlist_unhashed(&entry->d_u.d_alias)); if (inode) spin_lock(&inode->i_lock); @@ -1770,7 +1658,7 @@ EXPORT_SYMBOL(d_instantiate_unique); */ int d_instantiate_no_diralias(struct dentry *entry, struct inode *inode) { - BUG_ON(!hlist_unhashed(&entry->d_alias)); + BUG_ON(!hlist_unhashed(&entry->d_u.d_alias)); spin_lock(&inode->i_lock); if (S_ISDIR(inode->i_mode) && !hlist_empty(&inode->i_dentry)) { @@ -1809,7 +1697,7 @@ static struct dentry * __d_find_any_alias(struct inode *inode) if (hlist_empty(&inode->i_dentry)) return NULL; - alias = hlist_entry(inode->i_dentry.first, struct dentry, d_alias); + alias = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias); __dget(alias); return alias; } @@ -1886,7 +1774,7 @@ struct dentry *d_obtain_alias(struct inode *inode) spin_lock(&tmp->d_lock); tmp->d_inode = inode; tmp->d_flags |= add_flags; - hlist_add_head(&tmp->d_alias, &inode->i_dentry); + hlist_add_head(&tmp->d_u.d_alias, &inode->i_dentry); hlist_bl_lock(&tmp->d_sb->s_anon); hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon); hlist_bl_unlock(&tmp->d_sb->s_anon); @@ -2329,7 +2217,7 @@ int d_validate(struct dentry *dentry, struct dentry *dparent) struct dentry *child; spin_lock(&dparent->d_lock); - list_for_each_entry(child, &dparent->d_subdirs, d_u.d_child) { + list_for_each_entry(child, &dparent->d_subdirs, d_child) { if (dentry == child) { spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); __dget_dlock(dentry); @@ -2483,12 +2371,14 @@ static void switch_names(struct dentry *dentry, struct dentry *target) dentry->d_name.name = dentry->d_iname; } else { /* - * Both are internal. Just copy target to dentry + * Both are internal. */ - memcpy(dentry->d_iname, target->d_name.name, - target->d_name.len + 1); - dentry->d_name.len = target->d_name.len; - return; + unsigned int i; + BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long))); + for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) { + swap(((long *) &dentry->d_iname)[i], + ((long *) &target->d_iname)[i]); + } } } swap(dentry->d_name.len, target->d_name.len); @@ -2545,13 +2435,15 @@ static void dentry_unlock_parents_for_move(struct dentry *dentry, * __d_move - move a dentry * @dentry: entry to move * @target: new dentry + * @exchange: exchange the two dentries * * Update the dcache to reflect the move of a file name. Negative * dcache entries should not be moved in this way. Caller must hold * rename_lock, the i_mutex of the source and target directories, * and the sb->s_vfs_rename_mutex if they differ. See lock_rename(). */ -static void __d_move(struct dentry * dentry, struct dentry * target) +static void __d_move(struct dentry *dentry, struct dentry *target, + bool exchange) { if (!dentry->d_inode) printk(KERN_WARNING "VFS: moving negative dcache entry\n"); @@ -2573,11 +2465,18 @@ static void __d_move(struct dentry * dentry, struct dentry * target) __d_drop(dentry); __d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash)); - /* Unhash the target: dput() will then get rid of it */ + /* + * Unhash the target (d_delete() is not usable here). If exchanging + * the two dentries, then rehash onto the other's hash queue. + */ __d_drop(target); + if (exchange) { + __d_rehash(target, + d_hash(dentry->d_parent, dentry->d_name.hash)); + } - list_del(&dentry->d_u.d_child); - list_del(&target->d_u.d_child); + list_del(&dentry->d_child); + list_del(&target->d_child); /* Switch the names.. */ switch_names(dentry, target); @@ -2587,20 +2486,22 @@ static void __d_move(struct dentry * dentry, struct dentry * target) if (IS_ROOT(dentry)) { dentry->d_parent = target->d_parent; target->d_parent = target; - INIT_LIST_HEAD(&target->d_u.d_child); + INIT_LIST_HEAD(&target->d_child); } else { swap(dentry->d_parent, target->d_parent); /* And add them back to the (new) parent lists */ - list_add(&target->d_u.d_child, &target->d_parent->d_subdirs); + list_add(&target->d_child, &target->d_parent->d_subdirs); } - list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); + list_add(&dentry->d_child, &dentry->d_parent->d_subdirs); write_seqcount_end(&target->d_seq); write_seqcount_end(&dentry->d_seq); dentry_unlock_parents_for_move(dentry, target); + if (exchange) + fsnotify_d_move(target); spin_unlock(&target->d_lock); fsnotify_d_move(dentry); spin_unlock(&dentry->d_lock); @@ -2618,11 +2519,30 @@ static void __d_move(struct dentry * dentry, struct dentry * target) void d_move(struct dentry *dentry, struct dentry *target) { write_seqlock(&rename_lock); - __d_move(dentry, target); + __d_move(dentry, target, false); write_sequnlock(&rename_lock); } EXPORT_SYMBOL(d_move); +/* + * d_exchange - exchange two dentries + * @dentry1: first dentry + * @dentry2: second dentry + */ +void d_exchange(struct dentry *dentry1, struct dentry *dentry2) +{ + write_seqlock(&rename_lock); + + WARN_ON(!dentry1->d_inode); + WARN_ON(!dentry2->d_inode); + WARN_ON(IS_ROOT(dentry1)); + WARN_ON(IS_ROOT(dentry2)); + + __d_move(dentry1, dentry2, true); + + write_sequnlock(&rename_lock); +} + /** * d_ancestor - search for an ancestor * @p1: ancestor dentry @@ -2670,7 +2590,7 @@ static struct dentry *__d_unalias(struct inode *inode, m2 = &alias->d_parent->d_inode->i_mutex; out_unalias: if (likely(!d_mountpoint(alias))) { - __d_move(alias, dentry); + __d_move(alias, dentry, false); ret = alias; } out_err: @@ -2702,9 +2622,9 @@ static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon) swap(dentry->d_name.hash, anon->d_name.hash); dentry->d_parent = dentry; - list_del_init(&dentry->d_u.d_child); + list_del_init(&dentry->d_child); anon->d_parent = dparent; - list_move(&anon->d_u.d_child, &dparent->d_subdirs); + list_move(&anon->d_child, &dparent->d_subdirs); write_seqcount_end(&dentry->d_seq); write_seqcount_end(&anon->d_seq); @@ -2826,6 +2746,9 @@ static int prepend(char **buffer, int *buflen, const char *str, int namelen) * the beginning of the name. The sequence number check at the caller will * retry it again when a d_move() does happen. So any garbage in the buffer * due to mismatched pointer and length will be discarded. + * + * Data dependency barrier is needed to make sure that we see that terminating + * NUL. Alpha strikes again, film at 11... */ static int prepend_name(char **buffer, int *buflen, struct qstr *name) { @@ -2833,6 +2756,8 @@ static int prepend_name(char **buffer, int *buflen, struct qstr *name) u32 dlen = ACCESS_ONCE(name->len); char *p; + smp_read_barrier_depends(); + *buflen -= dlen + 1; if (*buflen < 0) return -ENAMETOOLONG; @@ -2894,6 +2819,13 @@ restart: if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) { struct mount *parent = ACCESS_ONCE(mnt->mnt_parent); + /* Escaped? */ + if (dentry != vfsmnt->mnt_root) { + bptr = *buffer; + blen = *buflen; + error = 3; + break; + } /* Global root? */ if (mnt != parent) { dentry = ACCESS_ONCE(mnt->mnt_mountpoint); @@ -2901,17 +2833,6 @@ restart: vfsmnt = &mnt->mnt; continue; } - /* - * Filesystems needing to implement special "root names" - * should do so with ->d_dname() - */ - if (IS_ROOT(dentry) && - (dentry->d_name.len != 1 || - dentry->d_name.name[0] != '/')) { - WARN(1, "Root dentry has weird name <%.*s>\n", - (int) dentry->d_name.len, - dentry->d_name.name); - } if (!error) error = is_mounted(vfsmnt) ? 1 : 2; break; @@ -3330,7 +3251,7 @@ void d_tmpfile(struct dentry *dentry, struct inode *inode) { inode_dec_link_count(inode); BUG_ON(dentry->d_name.name != dentry->d_iname || - !hlist_unhashed(&dentry->d_alias) || + !hlist_unhashed(&dentry->d_u.d_alias) || !d_unlinked(dentry)); spin_lock(&dentry->d_parent->d_lock); spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |