diff options
Diffstat (limited to 'fs/dcache.c')
-rw-r--r-- | fs/dcache.c | 272 |
1 files changed, 85 insertions, 187 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index 3ffef7f4e5cd..e368d4f412f9 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 @@ -252,14 +252,12 @@ 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)); kmem_cache_free(dentry_cache, dentry); } static void __d_free_external(struct rcu_head *head) { struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu); - WARN_ON(!hlist_unhashed(&dentry->d_alias)); kfree(external_name(dentry)); kmem_cache_free(dentry_cache, dentry); } @@ -271,6 +269,7 @@ static inline int dname_external(const struct dentry *dentry) static void dentry_free(struct dentry *dentry) { + WARN_ON(!hlist_unhashed(&dentry->d_u.d_alias)); if (unlikely(dname_external(dentry))) { struct external_name *p = external_name(dentry); if (likely(atomic_dec_and_test(&p->u.count))) { @@ -311,7 +310,7 @@ 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) @@ -336,7 +335,7 @@ 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); @@ -496,7 +495,7 @@ static void __dentry_kill(struct dentry *dentry) } /* if it was on the hash then remove it */ __d_drop(dentry); - list_del(&dentry->d_u.d_child); + __list_del_entry(&dentry->d_child); /* * Inform d_walk() that we are no longer attached to the * dentry tree @@ -722,7 +721,7 @@ static struct dentry *__d_find_alias(struct inode *inode) 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) && @@ -772,12 +771,13 @@ 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) { struct dentry *parent = lock_parent(dentry); if (likely(!dentry->d_lockref.count)) { __dentry_kill(dentry); + dput(parent); goto restart; } if (parent) @@ -1050,7 +1050,7 @@ 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); @@ -1082,33 +1082,31 @@ 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; + next = child->d_child.next; + while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED)) { + if (next == &this_parent->d_subdirs) + goto ascend; + child = list_entry(next, struct dentry, d_child); + next = next->next; } 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); @@ -1118,6 +1116,9 @@ out_unlock: return; rename_retry: + spin_unlock(&this_parent->d_lock); + rcu_read_unlock(); + BUG_ON(seq & 1); if (!retry) return; seq = 1; @@ -1454,8 +1455,8 @@ 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); @@ -1485,7 +1486,7 @@ 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; @@ -1578,7 +1579,7 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode) spin_lock(&dentry->d_lock); __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); @@ -1602,7 +1603,7 @@ 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); @@ -1641,7 +1642,7 @@ 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 @@ -1667,7 +1668,7 @@ 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); @@ -1698,7 +1699,7 @@ 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)) { @@ -1737,7 +1738,7 @@ 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; } @@ -1799,7 +1800,7 @@ static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected) 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); @@ -1888,51 +1889,19 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode, * if not go ahead and create it now. */ found = d_hash_and_lookup(dentry->d_parent, name); - if (unlikely(IS_ERR(found))) - goto err_out; if (!found) { new = d_alloc(dentry->d_parent, name); if (!new) { found = ERR_PTR(-ENOMEM); - goto err_out; - } - - found = d_splice_alias(inode, new); - if (found) { - dput(new); - return found; - } - return new; - } - - /* - * If a matching dentry exists, and it's not negative use it. - * - * Decrement the reference count to balance the iget() done - * earlier on. - */ - if (found->d_inode) { - if (unlikely(found->d_inode != inode)) { - /* This can't happen because bad inodes are unhashed. */ - BUG_ON(!is_bad_inode(inode)); - BUG_ON(!is_bad_inode(found->d_inode)); + } else { + found = d_splice_alias(inode, new); + if (found) { + dput(new); + return found; + } + return new; } - iput(inode); - return found; } - - /* - * Negative dentry: instantiate it unless the inode is a directory and - * already has a dentry. - */ - new = d_splice_alias(inode, found); - if (new) { - dput(found); - found = new; - } - return found; - -err_out: iput(inode); return found; } @@ -2234,7 +2203,7 @@ 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); @@ -2392,6 +2361,8 @@ static void swap_names(struct dentry *dentry, struct dentry *target) */ unsigned int i; BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long))); + kmemcheck_mark_initialized(dentry->d_iname, DNAME_INLINE_LEN); + kmemcheck_mark_initialized(target->d_iname, DNAME_INLINE_LEN); for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) { swap(((long *) &dentry->d_iname)[i], ((long *) &target->d_iname)[i]); @@ -2525,13 +2496,13 @@ static void __d_move(struct dentry *dentry, struct dentry *target, /* splicing a tree */ dentry->d_parent = target->d_parent; target->d_parent = target; - list_del_init(&target->d_u.d_child); - list_move(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); + list_del_init(&target->d_child); + list_move(&dentry->d_child, &dentry->d_parent->d_subdirs); } else { /* swapping two dentries */ swap(dentry->d_parent, target->d_parent); - list_move(&target->d_u.d_child, &target->d_parent->d_subdirs); - list_move(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); + list_move(&target->d_child, &target->d_parent->d_subdirs); + list_move(&dentry->d_child, &dentry->d_parent->d_subdirs); if (exchange) fsnotify_d_move(target); fsnotify_d_move(dentry); @@ -2607,11 +2578,11 @@ struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2) * Note: If ever the locking in lock_rename() changes, then please * remember to update this too... */ -static struct dentry *__d_unalias(struct inode *inode, +static int __d_unalias(struct inode *inode, struct dentry *dentry, struct dentry *alias) { struct mutex *m1 = NULL, *m2 = NULL; - struct dentry *ret = ERR_PTR(-EBUSY); + int ret = -EBUSY; /* If alias and dentry share a parent, then no extra locks required */ if (alias->d_parent == dentry->d_parent) @@ -2626,7 +2597,7 @@ static struct dentry *__d_unalias(struct inode *inode, m2 = &alias->d_parent->d_inode->i_mutex; out_unalias: __d_move(alias, dentry, false); - ret = alias; + ret = 0; out_err: spin_unlock(&inode->i_lock); if (m2) @@ -2661,130 +2632,57 @@ out_err: */ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) { - struct dentry *new = NULL; - if (IS_ERR(inode)) return ERR_CAST(inode); - if (inode && S_ISDIR(inode->i_mode)) { - spin_lock(&inode->i_lock); - new = __d_find_any_alias(inode); - if (new) { - if (!IS_ROOT(new)) { - spin_unlock(&inode->i_lock); - dput(new); - iput(inode); - return ERR_PTR(-EIO); - } - if (d_ancestor(new, dentry)) { - spin_unlock(&inode->i_lock); - dput(new); - iput(inode); - return ERR_PTR(-EIO); - } - write_seqlock(&rename_lock); - __d_move(new, dentry, false); - write_sequnlock(&rename_lock); - spin_unlock(&inode->i_lock); - security_d_instantiate(new, inode); - iput(inode); - } else { - /* already taking inode->i_lock, so d_add() by hand */ - __d_instantiate(dentry, inode); - spin_unlock(&inode->i_lock); - security_d_instantiate(dentry, inode); - d_rehash(dentry); - } - } else { - d_instantiate(dentry, inode); - if (d_unhashed(dentry)) - d_rehash(dentry); - } - return new; -} -EXPORT_SYMBOL(d_splice_alias); - -/** - * d_materialise_unique - introduce an inode into the tree - * @dentry: candidate dentry - * @inode: inode to bind to the dentry, to which aliases may be attached - * - * Introduces an dentry into the tree, substituting an extant disconnected - * root directory alias in its place if there is one. Caller must hold the - * i_mutex of the parent directory. - */ -struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) -{ - struct dentry *actual; - BUG_ON(!d_unhashed(dentry)); if (!inode) { - actual = dentry; __d_instantiate(dentry, NULL); - d_rehash(actual); - goto out_nolock; + goto out; } - spin_lock(&inode->i_lock); - if (S_ISDIR(inode->i_mode)) { - struct dentry *alias; - - /* Does an aliased dentry already exist? */ - alias = __d_find_alias(inode); - if (alias) { - actual = alias; + struct dentry *new = __d_find_any_alias(inode); + if (unlikely(new)) { write_seqlock(&rename_lock); - - if (d_ancestor(alias, dentry)) { - /* Check for loops */ - actual = ERR_PTR(-ELOOP); + if (unlikely(d_ancestor(new, dentry))) { + write_sequnlock(&rename_lock); spin_unlock(&inode->i_lock); - } else if (IS_ROOT(alias)) { - /* Is this an anonymous mountpoint that we - * could splice into our tree? */ - __d_move(alias, dentry, false); + dput(new); + new = ERR_PTR(-ELOOP); + pr_warn_ratelimited( + "VFS: Lookup of '%s' in %s %s" + " would have caused loop\n", + dentry->d_name.name, + inode->i_sb->s_type->name, + inode->i_sb->s_id); + } else if (!IS_ROOT(new)) { + int err = __d_unalias(inode, dentry, new); write_sequnlock(&rename_lock); - goto found; + if (err) { + dput(new); + new = ERR_PTR(err); + } } else { - /* Nope, but we must(!) avoid directory - * aliasing. This drops inode->i_lock */ - actual = __d_unalias(inode, dentry, alias); - } - write_sequnlock(&rename_lock); - if (IS_ERR(actual)) { - if (PTR_ERR(actual) == -ELOOP) - pr_warn_ratelimited( - "VFS: Lookup of '%s' in %s %s" - " would have caused loop\n", - dentry->d_name.name, - inode->i_sb->s_type->name, - inode->i_sb->s_id); - dput(alias); + __d_move(new, dentry, false); + write_sequnlock(&rename_lock); + spin_unlock(&inode->i_lock); + security_d_instantiate(new, inode); } - goto out_nolock; + iput(inode); + return new; } } - - /* Add a unique reference */ - actual = __d_instantiate_unique(dentry, inode); - if (!actual) - actual = dentry; - - d_rehash(actual); -found: + /* already taking inode->i_lock, so d_add() by hand */ + __d_instantiate(dentry, inode); spin_unlock(&inode->i_lock); -out_nolock: - if (actual == dentry) { - security_d_instantiate(dentry, inode); - return NULL; - } - - iput(inode); - return actual; +out: + security_d_instantiate(dentry, inode); + d_rehash(dentry); + return NULL; } -EXPORT_SYMBOL_GPL(d_materialise_unique); +EXPORT_SYMBOL(d_splice_alias); static int prepend(char **buffer, int *buflen, const char *str, int namelen) { @@ -3320,7 +3218,7 @@ 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); |