diff options
| -rw-r--r-- | fs/fuse/dev.c | 71 | ||||
| -rw-r--r-- | fs/fuse/fuse_i.h | 7 | ||||
| -rw-r--r-- | fs/fuse/inode.c | 16 |
3 files changed, 88 insertions, 6 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index c72e44b58d0..60c222517cc 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -260,11 +260,13 @@ static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED); restore_sigs(&oldset); spin_lock(&fuse_lock); - if (req->state == FUSE_REQ_FINISHED) + if (req->state == FUSE_REQ_FINISHED && !req->interrupted) return; - req->out.h.error = -EINTR; - req->interrupted = 1; + if (!req->interrupted) { + req->out.h.error = -EINTR; + req->interrupted = 1; + } if (req->locked) { /* This is uninterruptible sleep, because data is being copied to/from the buffers of req. During @@ -770,6 +772,10 @@ static ssize_t fuse_dev_writev(struct file *file, const struct iovec *iov, goto err_finish; spin_lock(&fuse_lock); + err = -ENOENT; + if (!fc->connected) + goto err_unlock; + req = request_find(fc, oh.unique); err = -EINVAL; if (!req) @@ -836,7 +842,11 @@ static unsigned fuse_dev_poll(struct file *file, poll_table *wait) return mask; } -/* Abort all requests on the given list (pending or processing) */ +/* + * Abort all requests on the given list (pending or processing) + * + * This function releases and reacquires fuse_lock + */ static void end_requests(struct fuse_conn *fc, struct list_head *head) { while (!list_empty(head)) { @@ -848,6 +858,59 @@ static void end_requests(struct fuse_conn *fc, struct list_head *head) } } +/* + * Abort requests under I/O + * + * The requests are set to interrupted and finished, and the request + * waiter is woken up. This will make request_wait_answer() wait + * until the request is unlocked and then return. + */ +static void end_io_requests(struct fuse_conn *fc) +{ + while (!list_empty(&fc->io)) { + struct fuse_req *req; + req = list_entry(fc->io.next, struct fuse_req, list); + req->interrupted = 1; + req->out.h.error = -ECONNABORTED; + req->state = FUSE_REQ_FINISHED; + list_del_init(&req->list); + wake_up(&req->waitq); + } +} + +/* + * Abort all requests. + * + * Emergency exit in case of a malicious or accidental deadlock, or + * just a hung filesystem. + * + * The same effect is usually achievable through killing the + * filesystem daemon and all users of the filesystem. The exception + * is the combination of an asynchronous request and the tricky + * deadlock (see Documentation/filesystems/fuse.txt). + * + * During the aborting, progression of requests from the pending and + * processing lists onto the io list, and progression of new requests + * onto the pending list is prevented by req->connected being false. + * + * Progression of requests under I/O to the processing list is + * prevented by the req->interrupted flag being true for these + * requests. For this reason requests on the io list must be aborted + * first. + */ +void fuse_abort_conn(struct fuse_conn *fc) +{ + spin_lock(&fuse_lock); + if (fc->connected) { + fc->connected = 0; + end_io_requests(fc); + end_requests(fc, &fc->pending); + end_requests(fc, &fc->processing); + wake_up_all(&fc->waitq); + } + spin_unlock(&fuse_lock); +} + static int fuse_dev_release(struct inode *inode, struct file *file) { struct fuse_conn *fc; diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index bcb453f6811..e6381db41df 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -246,8 +246,8 @@ struct fuse_conn { /** Mount is active */ unsigned mounted : 1; - /** Connection established, cleared on umount and device - release */ + /** Connection established, cleared on umount, connection + abort and device release */ unsigned connected : 1; /** Connection failed (version mismatch) */ @@ -463,6 +463,9 @@ void request_send_background(struct fuse_conn *fc, struct fuse_req *req); */ void fuse_release_background(struct fuse_req *req); +/* Abort all requests */ +void fuse_abort_conn(struct fuse_conn *fc); + /** * Get the attributes of a file */ diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 182235923cd..d359d8de22a 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -196,6 +196,11 @@ struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, return inode; } +static void fuse_umount_begin(struct super_block *sb) +{ + fuse_abort_conn(get_fuse_conn_super(sb)); +} + static void fuse_put_super(struct super_block *sb) { struct fuse_conn *fc = get_fuse_conn_super(sb); @@ -454,6 +459,7 @@ static struct super_operations fuse_super_operations = { .read_inode = fuse_read_inode, .clear_inode = fuse_clear_inode, .put_super = fuse_put_super, + .umount_begin = fuse_umount_begin, .statfs = fuse_statfs, .show_options = fuse_show_options, }; @@ -560,11 +566,21 @@ static ssize_t fuse_conn_waiting_show(struct fuse_conn *fc, char *page) return sprintf(page, "%i\n", atomic_read(&fc->num_waiting)); } +static ssize_t fuse_conn_abort_store(struct fuse_conn *fc, const char *page, + size_t count) +{ + fuse_abort_conn(fc); + return count; +} + static struct fuse_conn_attr fuse_conn_waiting = __ATTR(waiting, 0400, fuse_conn_waiting_show, NULL); +static struct fuse_conn_attr fuse_conn_abort = + __ATTR(abort, 0600, NULL, fuse_conn_abort_store); static struct attribute *fuse_conn_attrs[] = { &fuse_conn_waiting.attr, + &fuse_conn_abort.attr, NULL, }; |