*/
static void netfs_clear_unread(struct netfs_io_subrequest *subreq)
{
- struct iov_iter iter;
-
- iov_iter_xarray(&iter, READ, &subreq->rreq->mapping->i_pages,
- subreq->start + subreq->transferred,
- subreq->len - subreq->transferred);
- iov_iter_zero(iov_iter_count(&iter), &iter);
+ iov_iter_zero(iov_iter_count(&subreq->io_iter), &subreq->io_iter);
}
static void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error,
enum netfs_read_from_hole read_hole)
{
struct netfs_cache_resources *cres = &rreq->cache_resources;
- struct iov_iter iter;
netfs_stat(&netfs_n_rh_read);
- iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages,
- subreq->start + subreq->transferred,
- subreq->len - subreq->transferred);
-
- cres->ops->read(cres, subreq->start, &iter, read_hole,
+ cres->ops->read(cres, subreq->start, &subreq->io_iter, read_hole,
netfs_cache_read_terminated, subreq);
}
struct netfs_io_subrequest *subreq)
{
netfs_stat(&netfs_n_rh_download);
+ if (iov_iter_count(&subreq->io_iter) != subreq->len - subreq->transferred)
+ pr_warn("R=%08x[%u] ITER PRE-MISMATCH %zx != %zx-%zx %lx\n",
+ rreq->debug_id, subreq->debug_index,
+ iov_iter_count(&subreq->io_iter), subreq->len,
+ subreq->transferred, subreq->flags);
rreq->netfs_ops->issue_read(subreq);
}
if (have_unlocked && folio_index(folio) <= unlocked)
continue;
unlocked = folio_index(folio);
+ trace_netfs_folio(folio, netfs_folio_trace_end_copy);
folio_end_fscache(folio);
have_unlocked = true;
}
continue;
}
- iov_iter_xarray(&iter, WRITE, &rreq->mapping->i_pages,
+ iov_iter_xarray(&iter, ITER_SOURCE, &rreq->mapping->i_pages,
subreq->start, subreq->len);
atomic_inc(&rreq->nr_copy_ops);
netfs_read_from_server(rreq, subreq);
}
+/*
+ * Reset the subrequest iterator prior to resubmission.
+ */
+static void netfs_reset_subreq_iter(struct netfs_io_request *rreq,
+ struct netfs_io_subrequest *subreq)
+{
+ size_t remaining = subreq->len - subreq->transferred;
+ size_t count = iov_iter_count(&subreq->io_iter);
+
+ if (count == remaining)
+ return;
+
+ _debug("R=%08x[%u] ITER RESUB-MISMATCH %zx != %zx-%zx-%llx %x\n",
+ rreq->debug_id, subreq->debug_index,
+ iov_iter_count(&subreq->io_iter), subreq->transferred,
+ subreq->len, rreq->i_size,
+ subreq->io_iter.iter_type);
+
+ if (count < remaining)
+ iov_iter_revert(&subreq->io_iter, remaining - count);
+ else
+ iov_iter_advance(&subreq->io_iter, count - remaining);
+}
+
/*
* Resubmit any short or failed operations. Returns true if we got the rreq
* ref back.
trace_netfs_sreq(subreq, netfs_sreq_trace_download_instead);
netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
atomic_inc(&rreq->nr_outstanding);
+ netfs_reset_subreq_iter(rreq, subreq);
netfs_read_from_server(rreq, subreq);
} else if (test_bit(NETFS_SREQ_SHORT_IO, &subreq->flags)) {
netfs_rreq_short_read(rreq, subreq);
netfs_rreq_unlock_folios(rreq);
+ trace_netfs_rreq(rreq, netfs_rreq_trace_wake_ip);
clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
wake_up_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS);
struct netfs_io_request *rreq = subreq->rreq;
int u;
- _enter("[%u]{%llx,%lx},%zd",
- subreq->debug_index, subreq->start, subreq->flags,
- transferred_or_error);
+ _enter("R=%x[%x]{%llx,%lx},%zd",
+ rreq->debug_id, subreq->debug_index,
+ subreq->start, subreq->flags, transferred_or_error);
switch (subreq->source) {
case NETFS_READ_FROM_CACHE:
*/
static enum netfs_io_source
netfs_rreq_prepare_read(struct netfs_io_request *rreq,
- struct netfs_io_subrequest *subreq)
+ struct netfs_io_subrequest *subreq,
+ struct iov_iter *io_iter)
{
enum netfs_io_source source;
+ size_t lsize;
_enter("%llx-%llx,%llx", subreq->start, subreq->start + subreq->len, rreq->i_size);
source = NETFS_INVALID_READ;
goto out;
}
+
+ if (subreq->max_nr_segs) {
+ lsize = netfs_limit_iter(io_iter, 0, subreq->len,
+ subreq->max_nr_segs);
+ if (subreq->len > lsize) {
+ subreq->len = lsize;
+ trace_netfs_sreq(subreq, netfs_sreq_trace_limited);
+ }
+ }
}
- if (WARN_ON(subreq->len == 0))
+ if (subreq->len > rreq->len)
+ pr_warn("R=%08x[%u] SREQ>RREQ %zx > %zx\n",
+ rreq->debug_id, subreq->debug_index,
+ subreq->len, rreq->len);
+
+ if (WARN_ON(subreq->len == 0)) {
source = NETFS_INVALID_READ;
+ goto out;
+ }
+
+ subreq->source = source;
+ trace_netfs_sreq(subreq, netfs_sreq_trace_prepare);
+ subreq->io_iter = *io_iter;
+ iov_iter_truncate(&subreq->io_iter, subreq->len);
+ iov_iter_advance(io_iter, subreq->len);
out:
subreq->source = source;
trace_netfs_sreq(subreq, netfs_sreq_trace_prepare);
* Slice off a piece of a read request and submit an I/O request for it.
*/
static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq,
+ struct iov_iter *io_iter,
unsigned int *_debug_index)
{
struct netfs_io_subrequest *subreq;
* (the starts must coincide), in which case, we go around the loop
* again and ask it to download the next piece.
*/
- source = netfs_rreq_prepare_read(rreq, subreq);
+ source = netfs_rreq_prepare_read(rreq, subreq, io_iter);
if (source == NETFS_INVALID_READ)
goto subreq_failed;
*/
int netfs_begin_read(struct netfs_io_request *rreq, bool sync)
{
+ struct iov_iter io_iter;
unsigned int debug_index = 0;
int ret;
if (rreq->len == 0) {
pr_err("Zero-sized read [R=%x]\n", rreq->debug_id);
- netfs_put_request(rreq, false, netfs_rreq_trace_put_zero_len);
return -EIO;
}
- INIT_WORK(&rreq->work, netfs_rreq_work);
+ rreq->io_iter = rreq->iter;
- if (sync)
- netfs_get_request(rreq, netfs_rreq_trace_get_hold);
+ INIT_WORK(&rreq->work, netfs_rreq_work);
/* Chop the read into slices according to what the cache and the netfs
* want and submit each one.
*/
+ netfs_get_request(rreq, netfs_rreq_trace_get_for_outstanding);
atomic_set(&rreq->nr_outstanding, 1);
+ io_iter = rreq->io_iter;
do {
- if (!netfs_rreq_submit_slice(rreq, &debug_index))
+ if (!netfs_rreq_submit_slice(rreq, &io_iter, &debug_index))
break;
} while (rreq->submitted < rreq->len);
if (sync) {
- /* Keep nr_outstanding incremented so that the ref always belongs to
- * us, and the service code isn't punted off to a random thread pool to
- * process.
+ /* Keep nr_outstanding incremented so that the ref always
+ * belongs to us, and the service code isn't punted off to a
+ * random thread pool to process. Note that this might start
+ * further work, such as writing to the cache.
*/
- for (;;) {
- wait_var_event(&rreq->nr_outstanding,
- atomic_read(&rreq->nr_outstanding) == 1);
+ wait_var_event(&rreq->nr_outstanding,
+ atomic_read(&rreq->nr_outstanding) == 1);
+ if (atomic_dec_and_test(&rreq->nr_outstanding))
netfs_rreq_assess(rreq, false);
- if (!test_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags))
- break;
- cond_resched();
- }
+
+ trace_netfs_rreq(rreq, netfs_rreq_trace_wait_ip);
+ wait_on_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS,
+ TASK_UNINTERRUPTIBLE);
ret = rreq->error;
if (ret == 0 && rreq->submitted < rreq->len) {
trace_netfs_failure(rreq, NULL, ret, netfs_fail_short_read);
ret = -EIO;
}
- netfs_put_request(rreq, false, netfs_rreq_trace_put_hold);
} else {
/* If we decrement nr_outstanding to 0, the ref belongs to us. */
if (atomic_dec_and_test(&rreq->nr_outstanding))
projects / linux-2.6-block.git / blobdiff