diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ecryptfs/inode.c | 2 | ||||
| -rw-r--r-- | fs/eventpoll.c | 264 | ||||
| -rw-r--r-- | fs/namei.c | 4 | ||||
| -rw-r--r-- | fs/nfs/nfs4proc.c | 23 | ||||
| -rw-r--r-- | fs/nfs/nfs4state.c | 2 | ||||
| -rw-r--r-- | fs/nfs/nfs4xdr.c | 5 | ||||
| -rw-r--r-- | fs/signalfd.c | 15 |
7 files changed, 277 insertions, 38 deletions
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index d2039cafcafb..af11098c3b64 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -1104,6 +1104,8 @@ ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value, } rc = vfs_setxattr(lower_dentry, name, value, size, flags); + if (!rc) + fsstack_copy_attr_all(dentry->d_inode, lower_dentry->d_inode); out: return rc; } diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 53d6a207e93a..34294b931b9f 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -197,6 +197,12 @@ struct eventpoll { /* The user that created the eventpoll descriptor */ struct user_struct *user; + + struct file *file; + + /* used to optimize loop detection check */ + int visited; + struct list_head visited_list_link; }; /* Wait structure used by the poll hooks */ @@ -255,6 +261,15 @@ static struct kmem_cache *epi_cache __read_mostly; /* Slab cache used to allocate "struct eppoll_entry" */ static struct kmem_cache *pwq_cache __read_mostly; +/* Visited nodes during ep_loop_check(), so we can unset them when we finish */ +static LIST_HEAD(visited_list); + +/* + * List of files with newly added links, where we may need to limit the number + * of emanating paths. Protected by the epmutex. + */ +static LIST_HEAD(tfile_check_list); + #ifdef CONFIG_SYSCTL #include <linux/sysctl.h> @@ -276,6 +291,12 @@ ctl_table epoll_table[] = { }; #endif /* CONFIG_SYSCTL */ +static const struct file_operations eventpoll_fops; + +static inline int is_file_epoll(struct file *f) +{ + return f->f_op == &eventpoll_fops; +} /* Setup the structure that is used as key for the RB tree */ static inline void ep_set_ffd(struct epoll_filefd *ffd, @@ -299,6 +320,11 @@ static inline int ep_is_linked(struct list_head *p) return !list_empty(p); } +static inline struct eppoll_entry *ep_pwq_from_wait(wait_queue_t *p) +{ + return container_of(p, struct eppoll_entry, wait); +} + /* Get the "struct epitem" from a wait queue pointer */ static inline struct epitem *ep_item_from_wait(wait_queue_t *p) { @@ -446,6 +472,18 @@ static void ep_poll_safewake(wait_queue_head_t *wq) put_cpu_light(); } +static void ep_remove_wait_queue(struct eppoll_entry *pwq) +{ + wait_queue_head_t *whead; + + rcu_read_lock(); + /* If it is cleared by POLLFREE, it should be rcu-safe */ + whead = rcu_dereference(pwq->whead); + if (whead) + remove_wait_queue(whead, &pwq->wait); + rcu_read_unlock(); +} + /* * This function unregisters poll callbacks from the associated file * descriptor. Must be called with "mtx" held (or "epmutex" if called from @@ -460,7 +498,7 @@ static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi) pwq = list_first_entry(lsthead, struct eppoll_entry, llink); list_del(&pwq->llink); - remove_wait_queue(pwq->whead, &pwq->wait); + ep_remove_wait_queue(pwq); kmem_cache_free(pwq_cache, pwq); } } @@ -711,12 +749,6 @@ static const struct file_operations eventpoll_fops = { .llseek = noop_llseek, }; -/* Fast test to see if the file is an eventpoll file */ -static inline int is_file_epoll(struct file *f) -{ - return f->f_op == &eventpoll_fops; -} - /* * This is called from eventpoll_release() to unlink files from the eventpoll * interface. We need to have this facility to cleanup correctly files that are @@ -827,6 +859,17 @@ static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *k struct epitem *epi = ep_item_from_wait(wait); struct eventpoll *ep = epi->ep; + if ((unsigned long)key & POLLFREE) { + ep_pwq_from_wait(wait)->whead = NULL; + /* + * whead = NULL above can race with ep_remove_wait_queue() + * which can do another remove_wait_queue() after us, so we + * can't use __remove_wait_queue(). whead->lock is held by + * the caller. + */ + list_del_init(&wait->task_list); + } + spin_lock_irqsave(&ep->lock, flags); /* @@ -926,6 +969,99 @@ static void ep_rbtree_insert(struct eventpoll *ep, struct epitem *epi) rb_insert_color(&epi->rbn, &ep->rbr); } + + +#define PATH_ARR_SIZE 5 +/* + * These are the number paths of length 1 to 5, that we are allowing to emanate + * from a single file of interest. For example, we allow 1000 paths of length + * 1, to emanate from each file of interest. This essentially represents the + * potential wakeup paths, which need to be limited in order to avoid massive + * uncontrolled wakeup storms. The common use case should be a single ep which + * is connected to n file sources. In this case each file source has 1 path + * of length 1. Thus, the numbers below should be more than sufficient. These + * path limits are enforced during an EPOLL_CTL_ADD operation, since a modify + * and delete can't add additional paths. Protected by the epmutex. + */ +static const int path_limits[PATH_ARR_SIZE] = { 1000, 500, 100, 50, 10 }; +static int path_count[PATH_ARR_SIZE]; + +static int path_count_inc(int nests) +{ + if (++path_count[nests] > path_limits[nests]) + return -1; + return 0; +} + +static void path_count_init(void) +{ + int i; + + for (i = 0; i < PATH_ARR_SIZE; i++) + path_count[i] = 0; +} + +static int reverse_path_check_proc(void *priv, void *cookie, int call_nests) +{ + int error = 0; + struct file *file = priv; + struct file *child_file; + struct epitem *epi; + + list_for_each_entry(epi, &file->f_ep_links, fllink) { + child_file = epi->ep->file; + if (is_file_epoll(child_file)) { + if (list_empty(&child_file->f_ep_links)) { + if (path_count_inc(call_nests)) { + error = -1; + break; + } + } else { + error = ep_call_nested(&poll_loop_ncalls, + EP_MAX_NESTS, + reverse_path_check_proc, + child_file, child_file, + current); + } + if (error != 0) + break; + } else { + printk(KERN_ERR "reverse_path_check_proc: " + "file is not an ep!\n"); + } + } + return error; +} + +/** + * reverse_path_check - The tfile_check_list is list of file *, which have + * links that are proposed to be newly added. We need to + * make sure that those added links don't add too many + * paths such that we will spend all our time waking up + * eventpoll objects. + * + * Returns: Returns zero if the proposed links don't create too many paths, + * -1 otherwise. + */ +static int reverse_path_check(void) +{ + int length = 0; + int error = 0; + struct file *current_file; + + /* let's call this for all tfiles */ + list_for_each_entry(current_file, &tfile_check_list, f_tfile_llink) { + length++; + path_count_init(); + error = ep_call_nested(&poll_loop_ncalls, EP_MAX_NESTS, + reverse_path_check_proc, current_file, + current_file, current); + if (error) + break; + } + return error; +} + /* * Must be called with "mtx" held. */ @@ -987,6 +1123,11 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event, */ ep_rbtree_insert(ep, epi); + /* now check if we've created too many backpaths */ + error = -EINVAL; + if (reverse_path_check()) + goto error_remove_epi; + /* We have to drop the new item inside our item list to keep track of it */ spin_lock_irqsave(&ep->lock, flags); @@ -1011,6 +1152,14 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event, return 0; +error_remove_epi: + spin_lock(&tfile->f_lock); + if (ep_is_linked(&epi->fllink)) + list_del_init(&epi->fllink); + spin_unlock(&tfile->f_lock); + + rb_erase(&epi->rbn, &ep->rbr); + error_unregister: ep_unregister_pollwait(ep, epi); @@ -1275,18 +1424,36 @@ static int ep_loop_check_proc(void *priv, void *cookie, int call_nests) int error = 0; struct file *file = priv; struct eventpoll *ep = file->private_data; + struct eventpoll *ep_tovisit; struct rb_node *rbp; struct epitem *epi; mutex_lock_nested(&ep->mtx, call_nests + 1); + ep->visited = 1; + list_add(&ep->visited_list_link, &visited_list); for (rbp = rb_first(&ep->rbr); rbp; rbp = rb_next(rbp)) { epi = rb_entry(rbp, struct epitem, rbn); if (unlikely(is_file_epoll(epi->ffd.file))) { + ep_tovisit = epi->ffd.file->private_data; + if (ep_tovisit->visited) + continue; error = ep_call_nested(&poll_loop_ncalls, EP_MAX_NESTS, - ep_loop_check_proc, epi->ffd.file, - epi->ffd.file->private_data, current); + ep_loop_check_proc, epi->ffd.file, + ep_tovisit, current); if (error != 0) break; + } else { + /* + * If we've reached a file that is not associated with + * an ep, then we need to check if the newly added + * links are going to add too many wakeup paths. We do + * this by adding it to the tfile_check_list, if it's + * not already there, and calling reverse_path_check() + * during ep_insert(). + */ + if (list_empty(&epi->ffd.file->f_tfile_llink)) + list_add(&epi->ffd.file->f_tfile_llink, + &tfile_check_list); } } mutex_unlock(&ep->mtx); @@ -1307,8 +1474,31 @@ static int ep_loop_check_proc(void *priv, void *cookie, int call_nests) */ static int ep_loop_check(struct eventpoll *ep, struct file *file) { - return ep_call_nested(&poll_loop_ncalls, EP_MAX_NESTS, + int ret; + struct eventpoll *ep_cur, *ep_next; + + ret = ep_call_nested(&poll_loop_ncalls, EP_MAX_NESTS, ep_loop_check_proc, file, ep, current); + /* clear visited list */ + list_for_each_entry_safe(ep_cur, ep_next, &visited_list, + visited_list_link) { + ep_cur->visited = 0; + list_del(&ep_cur->visited_list_link); + } + return ret; +} + +static void clear_tfile_check_list(void) +{ + struct file *file; + + /* first clear the tfile_check_list */ + while (!list_empty(&tfile_check_list)) { + file = list_first_entry(&tfile_check_list, struct file, + f_tfile_llink); + list_del_init(&file->f_tfile_llink); + } + INIT_LIST_HEAD(&tfile_check_list); } /* @@ -1316,8 +1506,9 @@ static int ep_loop_check(struct eventpoll *ep, struct file *file) */ SYSCALL_DEFINE1(epoll_create1, int, flags) { - int error; + int error, fd; struct eventpoll *ep = NULL; + struct file *file; /* Check the EPOLL_* constant for consistency. */ BUILD_BUG_ON(EPOLL_CLOEXEC != O_CLOEXEC); @@ -1334,11 +1525,25 @@ SYSCALL_DEFINE1(epoll_create1, int, flags) * Creates all the items needed to setup an eventpoll file. That is, * a file structure and a free file descriptor. */ - error = anon_inode_getfd("[eventpoll]", &eventpoll_fops, ep, + fd = get_unused_fd_flags(O_RDWR | (flags & O_CLOEXEC)); + if (fd < 0) { + error = fd; + goto out_free_ep; + } + file = anon_inode_getfile("[eventpoll]", &eventpoll_fops, ep, O_RDWR | (flags & O_CLOEXEC)); - if (error < 0) - ep_free(ep); - + if (IS_ERR(file)) { + error = PTR_ERR(file); + goto out_free_fd; + } + fd_install(fd, file); + ep->file = file; + return fd; + +out_free_fd: + put_unused_fd(fd); +out_free_ep: + ep_free(ep); return error; } @@ -1404,21 +1609,27 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, /* * When we insert an epoll file descriptor, inside another epoll file * descriptor, there is the change of creating closed loops, which are - * better be handled here, than in more critical paths. + * better be handled here, than in more critical paths. While we are + * checking for loops we also determine the list of files reachable + * and hang them on the tfile_check_list, so we can check that we + * haven't created too many possible wakeup paths. * - * We hold epmutex across the loop check and the insert in this case, in - * order to prevent two separate inserts from racing and each doing the - * insert "at the same time" such that ep_loop_check passes on both - * before either one does the insert, thereby creating a cycle. + * We need to hold the epmutex across both ep_insert and ep_remove + * b/c we want to make sure we are looking at a coherent view of + * epoll network. */ - if (unlikely(is_file_epoll(tfile) && op == EPOLL_CTL_ADD)) { + if (op == EPOLL_CTL_ADD || op == EPOLL_CTL_DEL) { mutex_lock(&epmutex); did_lock_epmutex = 1; - error = -ELOOP; - if (ep_loop_check(ep, tfile) != 0) - goto error_tgt_fput; } - + if (op == EPOLL_CTL_ADD) { + if (is_file_epoll(tfile)) { + error = -ELOOP; + if (ep_loop_check(ep, tfile) != 0) + goto error_tgt_fput; + } else + list_add(&tfile->f_tfile_llink, &tfile_check_list); + } mutex_lock_nested(&ep->mtx, 0); @@ -1437,6 +1648,7 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, error = ep_insert(ep, &epds, tfile, fd); } else error = -EEXIST; + clear_tfile_check_list(); break; case EPOLL_CTL_DEL: if (epi) @@ -1455,7 +1667,7 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, mutex_unlock(&ep->mtx); error_tgt_fput: - if (unlikely(did_lock_epmutex)) + if (did_lock_epmutex) mutex_unlock(&epmutex); fput(tfile); diff --git a/fs/namei.c b/fs/namei.c index 5008f01787f5..744e942fbf45 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1094,8 +1094,10 @@ static struct dentry *d_inode_lookup(struct dentry *parent, struct dentry *dentr struct dentry *old; /* Don't create child dentry for a dead directory. */ - if (unlikely(IS_DEADDIR(inode))) + if (unlikely(IS_DEADDIR(inode))) { + dput(dentry); return ERR_PTR(-ENOENT); + } old = inode->i_op->lookup(inode, dentry, nd); if (unlikely(old)) { diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 055d7027f7a9..e52703080c6d 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -3568,8 +3568,8 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu } if (npages > 1) { /* for decoding across pages */ - args.acl_scratch = alloc_page(GFP_KERNEL); - if (!args.acl_scratch) + res.acl_scratch = alloc_page(GFP_KERNEL); + if (!res.acl_scratch) goto out_free; } args.acl_len = npages * PAGE_SIZE; @@ -3605,8 +3605,8 @@ out_free: for (i = 0; i < npages; i++) if (pages[i]) __free_page(pages[i]); - if (args.acl_scratch) - __free_page(args.acl_scratch); + if (res.acl_scratch) + __free_page(res.acl_scratch); return ret; } @@ -4876,8 +4876,10 @@ int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred) clp->cl_rpcclient->cl_auth->au_flavor); res.server_scope = kzalloc(sizeof(struct server_scope), GFP_KERNEL); - if (unlikely(!res.server_scope)) - return -ENOMEM; + if (unlikely(!res.server_scope)) { + status = -ENOMEM; + goto out; + } status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT); if (!status) @@ -4894,12 +4896,13 @@ int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred) clp->server_scope = NULL; } - if (!clp->server_scope) + if (!clp->server_scope) { clp->server_scope = res.server_scope; - else - kfree(res.server_scope); + goto out; + } } - + kfree(res.server_scope); +out: dprintk("<-- %s status= %d\n", __func__, status); return status; } diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index 6a7107ae6b72..a58eed784aed 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -1071,6 +1071,8 @@ void nfs4_schedule_stateid_recovery(const struct nfs_server *server, struct nfs4 { struct nfs_client *clp = server->nfs_client; + if (test_and_clear_bit(NFS_DELEGATED_STATE, &state->flags)) + nfs_async_inode_return_delegation(state->inode, &state->stateid); nfs4_state_mark_reclaim_nograce(clp, state); nfs4_schedule_state_manager(clp); } diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c index dcaf69309d8e..68adab41dbcb 100644 --- a/fs/nfs/nfs4xdr.c +++ b/fs/nfs/nfs4xdr.c @@ -2522,7 +2522,6 @@ static void nfs4_xdr_enc_getacl(struct rpc_rqst *req, struct xdr_stream *xdr, xdr_inline_pages(&req->rq_rcv_buf, replen << 2, args->acl_pages, args->acl_pgbase, args->acl_len); - xdr_set_scratch_buffer(xdr, page_address(args->acl_scratch), PAGE_SIZE); encode_nops(&hdr); } @@ -6034,6 +6033,10 @@ nfs4_xdr_dec_getacl(struct rpc_rqst *rqstp, struct xdr_stream *xdr, struct compound_hdr hdr; int status; + if (res->acl_scratch != NULL) { + void *p = page_address(res->acl_scratch); + xdr_set_scratch_buffer(xdr, p, PAGE_SIZE); + } status = decode_compound_hdr(xdr, &hdr); if (status) goto out; diff --git a/fs/signalfd.c b/fs/signalfd.c index 492465b451dd..7ae2a574cb25 100644 --- a/fs/signalfd.c +++ b/fs/signalfd.c @@ -30,6 +30,21 @@ #include <linux/signalfd.h> #include <linux/syscalls.h> +void signalfd_cleanup(struct sighand_struct *sighand) +{ + wait_queue_head_t *wqh = &sighand->signalfd_wqh; + /* + * The lockless check can race with remove_wait_queue() in progress, + * but in this case its caller should run under rcu_read_lock() and + * sighand_cachep is SLAB_DESTROY_BY_RCU, we can safely return. + */ + if (likely(!waitqueue_active(wqh))) + return; + + /* wait_queue_t->func(POLLFREE) should do remove_wait_queue() */ + wake_up_poll(wqh, POLLHUP | POLLFREE); +} + struct signalfd_ctx { sigset_t sigmask; }; |