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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-18 18:50:12 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-18 18:50:12 +0000
commit8665bd53f2f2e27e5511d90428cb3f60e6d0ce15 (patch)
tree8d58900dc0ebd4a3011f92c128d2fe45bc7c4bf2 /fs/netfs/fscache_io.c
parentAdding debian version 6.7.12-1. (diff)
downloadlinux-8665bd53f2f2e27e5511d90428cb3f60e6d0ce15.tar.xz
linux-8665bd53f2f2e27e5511d90428cb3f60e6d0ce15.zip
Merging upstream version 6.8.9.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/netfs/fscache_io.c')
-rw-r--r--fs/netfs/fscache_io.c287
1 files changed, 287 insertions, 0 deletions
diff --git a/fs/netfs/fscache_io.c b/fs/netfs/fscache_io.c
new file mode 100644
index 0000000000..ad572f7ee8
--- /dev/null
+++ b/fs/netfs/fscache_io.c
@@ -0,0 +1,287 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Cache data I/O routines
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+#define FSCACHE_DEBUG_LEVEL OPERATION
+#include <linux/fscache-cache.h>
+#include <linux/uio.h>
+#include <linux/bvec.h>
+#include <linux/slab.h>
+#include <linux/uio.h>
+#include "internal.h"
+
+/**
+ * fscache_wait_for_operation - Wait for an object become accessible
+ * @cres: The cache resources for the operation being performed
+ * @want_state: The minimum state the object must be at
+ *
+ * See if the target cache object is at the specified minimum state of
+ * accessibility yet, and if not, wait for it.
+ */
+bool fscache_wait_for_operation(struct netfs_cache_resources *cres,
+ enum fscache_want_state want_state)
+{
+ struct fscache_cookie *cookie = fscache_cres_cookie(cres);
+ enum fscache_cookie_state state;
+
+again:
+ if (!fscache_cache_is_live(cookie->volume->cache)) {
+ _leave(" [broken]");
+ return false;
+ }
+
+ state = fscache_cookie_state(cookie);
+ _enter("c=%08x{%u},%x", cookie->debug_id, state, want_state);
+
+ switch (state) {
+ case FSCACHE_COOKIE_STATE_CREATING:
+ case FSCACHE_COOKIE_STATE_INVALIDATING:
+ if (want_state == FSCACHE_WANT_PARAMS)
+ goto ready; /* There can be no content */
+ fallthrough;
+ case FSCACHE_COOKIE_STATE_LOOKING_UP:
+ case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
+ wait_var_event(&cookie->state,
+ fscache_cookie_state(cookie) != state);
+ goto again;
+
+ case FSCACHE_COOKIE_STATE_ACTIVE:
+ goto ready;
+ case FSCACHE_COOKIE_STATE_DROPPED:
+ case FSCACHE_COOKIE_STATE_RELINQUISHING:
+ default:
+ _leave(" [not live]");
+ return false;
+ }
+
+ready:
+ if (!cres->cache_priv2)
+ return cookie->volume->cache->ops->begin_operation(cres, want_state);
+ return true;
+}
+EXPORT_SYMBOL(fscache_wait_for_operation);
+
+/*
+ * Begin an I/O operation on the cache, waiting till we reach the right state.
+ *
+ * Attaches the resources required to the operation resources record.
+ */
+static int fscache_begin_operation(struct netfs_cache_resources *cres,
+ struct fscache_cookie *cookie,
+ enum fscache_want_state want_state,
+ enum fscache_access_trace why)
+{
+ enum fscache_cookie_state state;
+ long timeo;
+ bool once_only = false;
+
+ cres->ops = NULL;
+ cres->cache_priv = cookie;
+ cres->cache_priv2 = NULL;
+ cres->debug_id = cookie->debug_id;
+ cres->inval_counter = cookie->inval_counter;
+
+ if (!fscache_begin_cookie_access(cookie, why))
+ return -ENOBUFS;
+
+again:
+ spin_lock(&cookie->lock);
+
+ state = fscache_cookie_state(cookie);
+ _enter("c=%08x{%u},%x", cookie->debug_id, state, want_state);
+
+ switch (state) {
+ case FSCACHE_COOKIE_STATE_LOOKING_UP:
+ case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
+ case FSCACHE_COOKIE_STATE_INVALIDATING:
+ goto wait_for_file_wrangling;
+ case FSCACHE_COOKIE_STATE_CREATING:
+ if (want_state == FSCACHE_WANT_PARAMS)
+ goto ready; /* There can be no content */
+ goto wait_for_file_wrangling;
+ case FSCACHE_COOKIE_STATE_ACTIVE:
+ goto ready;
+ case FSCACHE_COOKIE_STATE_DROPPED:
+ case FSCACHE_COOKIE_STATE_RELINQUISHING:
+ WARN(1, "Can't use cookie in state %u\n", cookie->state);
+ goto not_live;
+ default:
+ goto not_live;
+ }
+
+ready:
+ spin_unlock(&cookie->lock);
+ if (!cookie->volume->cache->ops->begin_operation(cres, want_state))
+ goto failed;
+ return 0;
+
+wait_for_file_wrangling:
+ spin_unlock(&cookie->lock);
+ trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref),
+ atomic_read(&cookie->n_accesses),
+ fscache_access_io_wait);
+ timeo = wait_var_event_timeout(&cookie->state,
+ fscache_cookie_state(cookie) != state, 20 * HZ);
+ if (timeo <= 1 && !once_only) {
+ pr_warn("%s: cookie state change wait timed out: cookie->state=%u state=%u",
+ __func__, fscache_cookie_state(cookie), state);
+ fscache_print_cookie(cookie, 'O');
+ once_only = true;
+ }
+ goto again;
+
+not_live:
+ spin_unlock(&cookie->lock);
+failed:
+ cres->cache_priv = NULL;
+ cres->ops = NULL;
+ fscache_end_cookie_access(cookie, fscache_access_io_not_live);
+ _leave(" = -ENOBUFS");
+ return -ENOBUFS;
+}
+
+int __fscache_begin_read_operation(struct netfs_cache_resources *cres,
+ struct fscache_cookie *cookie)
+{
+ return fscache_begin_operation(cres, cookie, FSCACHE_WANT_PARAMS,
+ fscache_access_io_read);
+}
+EXPORT_SYMBOL(__fscache_begin_read_operation);
+
+int __fscache_begin_write_operation(struct netfs_cache_resources *cres,
+ struct fscache_cookie *cookie)
+{
+ return fscache_begin_operation(cres, cookie, FSCACHE_WANT_PARAMS,
+ fscache_access_io_write);
+}
+EXPORT_SYMBOL(__fscache_begin_write_operation);
+
+struct fscache_write_request {
+ struct netfs_cache_resources cache_resources;
+ struct address_space *mapping;
+ loff_t start;
+ size_t len;
+ bool set_bits;
+ netfs_io_terminated_t term_func;
+ void *term_func_priv;
+};
+
+void __fscache_clear_page_bits(struct address_space *mapping,
+ loff_t start, size_t len)
+{
+ pgoff_t first = start / PAGE_SIZE;
+ pgoff_t last = (start + len - 1) / PAGE_SIZE;
+ struct page *page;
+
+ if (len) {
+ XA_STATE(xas, &mapping->i_pages, first);
+
+ rcu_read_lock();
+ xas_for_each(&xas, page, last) {
+ end_page_fscache(page);
+ }
+ rcu_read_unlock();
+ }
+}
+EXPORT_SYMBOL(__fscache_clear_page_bits);
+
+/*
+ * Deal with the completion of writing the data to the cache.
+ */
+static void fscache_wreq_done(void *priv, ssize_t transferred_or_error,
+ bool was_async)
+{
+ struct fscache_write_request *wreq = priv;
+
+ fscache_clear_page_bits(wreq->mapping, wreq->start, wreq->len,
+ wreq->set_bits);
+
+ if (wreq->term_func)
+ wreq->term_func(wreq->term_func_priv, transferred_or_error,
+ was_async);
+ fscache_end_operation(&wreq->cache_resources);
+ kfree(wreq);
+}
+
+void __fscache_write_to_cache(struct fscache_cookie *cookie,
+ struct address_space *mapping,
+ loff_t start, size_t len, loff_t i_size,
+ netfs_io_terminated_t term_func,
+ void *term_func_priv,
+ bool cond)
+{
+ struct fscache_write_request *wreq;
+ struct netfs_cache_resources *cres;
+ struct iov_iter iter;
+ int ret = -ENOBUFS;
+
+ if (len == 0)
+ goto abandon;
+
+ _enter("%llx,%zx", start, len);
+
+ wreq = kzalloc(sizeof(struct fscache_write_request), GFP_NOFS);
+ if (!wreq)
+ goto abandon;
+ wreq->mapping = mapping;
+ wreq->start = start;
+ wreq->len = len;
+ wreq->set_bits = cond;
+ wreq->term_func = term_func;
+ wreq->term_func_priv = term_func_priv;
+
+ cres = &wreq->cache_resources;
+ if (fscache_begin_operation(cres, cookie, FSCACHE_WANT_WRITE,
+ fscache_access_io_write) < 0)
+ goto abandon_free;
+
+ ret = cres->ops->prepare_write(cres, &start, &len, len, i_size, false);
+ if (ret < 0)
+ goto abandon_end;
+
+ /* TODO: Consider clearing page bits now for space the write isn't
+ * covering. This is more complicated than it appears when THPs are
+ * taken into account.
+ */
+
+ iov_iter_xarray(&iter, ITER_SOURCE, &mapping->i_pages, start, len);
+ fscache_write(cres, start, &iter, fscache_wreq_done, wreq);
+ return;
+
+abandon_end:
+ return fscache_wreq_done(wreq, ret, false);
+abandon_free:
+ kfree(wreq);
+abandon:
+ fscache_clear_page_bits(mapping, start, len, cond);
+ if (term_func)
+ term_func(term_func_priv, ret, false);
+}
+EXPORT_SYMBOL(__fscache_write_to_cache);
+
+/*
+ * Change the size of a backing object.
+ */
+void __fscache_resize_cookie(struct fscache_cookie *cookie, loff_t new_size)
+{
+ struct netfs_cache_resources cres;
+
+ trace_fscache_resize(cookie, new_size);
+ if (fscache_begin_operation(&cres, cookie, FSCACHE_WANT_WRITE,
+ fscache_access_io_resize) == 0) {
+ fscache_stat(&fscache_n_resizes);
+ set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &cookie->flags);
+
+ /* We cannot defer a resize as we need to do it inside the
+ * netfs's inode lock so that we're serialised with respect to
+ * writes.
+ */
+ cookie->volume->cache->ops->resize_cookie(&cres, new_size);
+ fscache_end_operation(&cres);
+ } else {
+ fscache_stat(&fscache_n_resizes_null);
+ }
+}
+EXPORT_SYMBOL(__fscache_resize_cookie);