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Diffstat (limited to 'fs/fscache/page.c')
-rw-r--r--fs/fscache/page.c195
1 files changed, 158 insertions, 37 deletions
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index 3f7a59bfa7a..ff000e52072 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -56,6 +56,7 @@ bool __fscache_maybe_release_page(struct fscache_cookie *cookie,
_enter("%p,%p,%x", cookie, page, gfp);
+try_again:
rcu_read_lock();
val = radix_tree_lookup(&cookie->stores, page->index);
if (!val) {
@@ -104,11 +105,19 @@ bool __fscache_maybe_release_page(struct fscache_cookie *cookie,
return true;
page_busy:
- /* we might want to wait here, but that could deadlock the allocator as
- * the work threads writing to the cache may all end up sleeping
- * on memory allocation */
- fscache_stat(&fscache_n_store_vmscan_busy);
- return false;
+ /* We will wait here if we're allowed to, but that could deadlock the
+ * allocator as the work threads writing to the cache may all end up
+ * sleeping on memory allocation, so we may need to impose a timeout
+ * too. */
+ if (!(gfp & __GFP_WAIT)) {
+ fscache_stat(&fscache_n_store_vmscan_busy);
+ return false;
+ }
+
+ fscache_stat(&fscache_n_store_vmscan_wait);
+ __fscache_wait_on_page_write(cookie, page);
+ gfp &= ~__GFP_WAIT;
+ goto try_again;
}
EXPORT_SYMBOL(__fscache_maybe_release_page);
@@ -162,6 +171,7 @@ static void fscache_attr_changed_op(struct fscache_operation *op)
fscache_abort_object(object);
}
+ fscache_op_complete(op, true);
_leave("");
}
@@ -223,6 +233,8 @@ static void fscache_release_retrieval_op(struct fscache_operation *_op)
_enter("{OP%x}", op->op.debug_id);
+ ASSERTCMP(op->n_pages, ==, 0);
+
fscache_hist(fscache_retrieval_histogram, op->start_time);
if (op->context)
fscache_put_context(op->op.object->cookie, op->context);
@@ -291,6 +303,17 @@ static int fscache_wait_for_deferred_lookup(struct fscache_cookie *cookie)
}
/*
+ * Handle cancellation of a pending retrieval op
+ */
+static void fscache_do_cancel_retrieval(struct fscache_operation *_op)
+{
+ struct fscache_retrieval *op =
+ container_of(_op, struct fscache_retrieval, op);
+
+ op->n_pages = 0;
+}
+
+/*
* wait for an object to become active (or dead)
*/
static int fscache_wait_for_retrieval_activation(struct fscache_object *object,
@@ -307,8 +330,8 @@ static int fscache_wait_for_retrieval_activation(struct fscache_object *object,
fscache_stat(stat_op_waits);
if (wait_on_bit(&op->op.flags, FSCACHE_OP_WAITING,
fscache_wait_bit_interruptible,
- TASK_INTERRUPTIBLE) < 0) {
- ret = fscache_cancel_op(&op->op);
+ TASK_INTERRUPTIBLE) != 0) {
+ ret = fscache_cancel_op(&op->op, fscache_do_cancel_retrieval);
if (ret == 0)
return -ERESTARTSYS;
@@ -320,7 +343,14 @@ static int fscache_wait_for_retrieval_activation(struct fscache_object *object,
_debug("<<< GO");
check_if_dead:
+ if (op->op.state == FSCACHE_OP_ST_CANCELLED) {
+ fscache_stat(stat_object_dead);
+ _leave(" = -ENOBUFS [cancelled]");
+ return -ENOBUFS;
+ }
if (unlikely(fscache_object_is_dead(object))) {
+ pr_err("%s() = -ENOBUFS [obj dead %d]\n", __func__, op->op.state);
+ fscache_cancel_op(&op->op, fscache_do_cancel_retrieval);
fscache_stat(stat_object_dead);
return -ENOBUFS;
}
@@ -353,6 +383,11 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
if (hlist_empty(&cookie->backing_objects))
goto nobufs;
+ if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
+ _leave(" = -ENOBUFS [invalidating]");
+ return -ENOBUFS;
+ }
+
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
ASSERTCMP(page, !=, NULL);
@@ -364,6 +399,7 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
_leave(" = -ENOMEM");
return -ENOMEM;
}
+ op->n_pages = 1;
spin_lock(&cookie->lock);
@@ -375,10 +411,10 @@ int __fscache_read_or_alloc_page(struct fscache_cookie *cookie,
ASSERTCMP(object->state, >, FSCACHE_OBJECT_LOOKING_UP);
atomic_inc(&object->n_reads);
- set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
+ __set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
if (fscache_submit_op(object, &op->op) < 0)
- goto nobufs_unlock;
+ goto nobufs_unlock_dec;
spin_unlock(&cookie->lock);
fscache_stat(&fscache_n_retrieval_ops);
@@ -425,6 +461,8 @@ error:
_leave(" = %d", ret);
return ret;
+nobufs_unlock_dec:
+ atomic_dec(&object->n_reads);
nobufs_unlock:
spin_unlock(&cookie->lock);
kfree(op);
@@ -472,6 +510,11 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
if (hlist_empty(&cookie->backing_objects))
goto nobufs;
+ if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
+ _leave(" = -ENOBUFS [invalidating]");
+ return -ENOBUFS;
+ }
+
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
ASSERTCMP(*nr_pages, >, 0);
ASSERT(!list_empty(pages));
@@ -482,6 +525,7 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
op = fscache_alloc_retrieval(mapping, end_io_func, context);
if (!op)
return -ENOMEM;
+ op->n_pages = *nr_pages;
spin_lock(&cookie->lock);
@@ -491,10 +535,10 @@ int __fscache_read_or_alloc_pages(struct fscache_cookie *cookie,
struct fscache_object, cookie_link);
atomic_inc(&object->n_reads);
- set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
+ __set_bit(FSCACHE_OP_DEC_READ_CNT, &op->op.flags);
if (fscache_submit_op(object, &op->op) < 0)
- goto nobufs_unlock;
+ goto nobufs_unlock_dec;
spin_unlock(&cookie->lock);
fscache_stat(&fscache_n_retrieval_ops);
@@ -541,6 +585,8 @@ error:
_leave(" = %d", ret);
return ret;
+nobufs_unlock_dec:
+ atomic_dec(&object->n_reads);
nobufs_unlock:
spin_unlock(&cookie->lock);
kfree(op);
@@ -577,12 +623,18 @@ int __fscache_alloc_page(struct fscache_cookie *cookie,
ASSERTCMP(cookie->def->type, !=, FSCACHE_COOKIE_TYPE_INDEX);
ASSERTCMP(page, !=, NULL);
+ if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
+ _leave(" = -ENOBUFS [invalidating]");
+ return -ENOBUFS;
+ }
+
if (fscache_wait_for_deferred_lookup(cookie) < 0)
return -ERESTARTSYS;
op = fscache_alloc_retrieval(page->mapping, NULL, NULL);
if (!op)
return -ENOMEM;
+ op->n_pages = 1;
spin_lock(&cookie->lock);
@@ -658,9 +710,27 @@ static void fscache_write_op(struct fscache_operation *_op)
spin_lock(&object->lock);
cookie = object->cookie;
- if (!fscache_object_is_active(object) || !cookie) {
+ if (!fscache_object_is_active(object)) {
+ /* If we get here, then the on-disk cache object likely longer
+ * exists, so we should just cancel this write operation.
+ */
+ spin_unlock(&object->lock);
+ fscache_op_complete(&op->op, false);
+ _leave(" [inactive]");
+ return;
+ }
+
+ if (!cookie) {
+ /* If we get here, then the cookie belonging to the object was
+ * detached, probably by the cookie being withdrawn due to
+ * memory pressure, which means that the pages we might write
+ * to the cache from no longer exist - therefore, we can just
+ * cancel this write operation.
+ */
spin_unlock(&object->lock);
- _leave("");
+ fscache_op_complete(&op->op, false);
+ _leave(" [cancel] op{f=%lx s=%u} obj{s=%u f=%lx}",
+ _op->flags, _op->state, object->state, object->flags);
return;
}
@@ -696,6 +766,7 @@ static void fscache_write_op(struct fscache_operation *_op)
fscache_end_page_write(object, page);
if (ret < 0) {
fscache_abort_object(object);
+ fscache_op_complete(&op->op, true);
} else {
fscache_enqueue_operation(&op->op);
}
@@ -710,6 +781,38 @@ superseded:
spin_unlock(&cookie->stores_lock);
clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
spin_unlock(&object->lock);
+ fscache_op_complete(&op->op, true);
+ _leave("");
+}
+
+/*
+ * Clear the pages pending writing for invalidation
+ */
+void fscache_invalidate_writes(struct fscache_cookie *cookie)
+{
+ struct page *page;
+ void *results[16];
+ int n, i;
+
+ _enter("");
+
+ while (spin_lock(&cookie->stores_lock),
+ n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0,
+ ARRAY_SIZE(results),
+ FSCACHE_COOKIE_PENDING_TAG),
+ n > 0) {
+ for (i = n - 1; i >= 0; i--) {
+ page = results[i];
+ radix_tree_delete(&cookie->stores, page->index);
+ }
+
+ spin_unlock(&cookie->stores_lock);
+
+ for (i = n - 1; i >= 0; i--)
+ page_cache_release(results[i]);
+ }
+
+ spin_unlock(&cookie->stores_lock);
_leave("");
}
@@ -759,7 +862,12 @@ int __fscache_write_page(struct fscache_cookie *cookie,
fscache_stat(&fscache_n_stores);
- op = kzalloc(sizeof(*op), GFP_NOIO);
+ if (test_bit(FSCACHE_COOKIE_INVALIDATING, &cookie->flags)) {
+ _leave(" = -ENOBUFS [invalidating]");
+ return -ENOBUFS;
+ }
+
+ op = kzalloc(sizeof(*op), GFP_NOIO | __GFP_NOMEMALLOC | __GFP_NORETRY);
if (!op)
goto nomem;
@@ -915,6 +1023,40 @@ done:
EXPORT_SYMBOL(__fscache_uncache_page);
/**
+ * fscache_mark_page_cached - Mark a page as being cached
+ * @op: The retrieval op pages are being marked for
+ * @page: The page to be marked
+ *
+ * Mark a netfs page as being cached. After this is called, the netfs
+ * must call fscache_uncache_page() to remove the mark.
+ */
+void fscache_mark_page_cached(struct fscache_retrieval *op, struct page *page)
+{
+ struct fscache_cookie *cookie = op->op.object->cookie;
+
+#ifdef CONFIG_FSCACHE_STATS
+ atomic_inc(&fscache_n_marks);
+#endif
+
+ _debug("- mark %p{%lx}", page, page->index);
+ if (TestSetPageFsCache(page)) {
+ static bool once_only;
+ if (!once_only) {
+ once_only = true;
+ printk(KERN_WARNING "FS-Cache:"
+ " Cookie type %s marked page %lx"
+ " multiple times\n",
+ cookie->def->name, page->index);
+ }
+ }
+
+ if (cookie->def->mark_page_cached)
+ cookie->def->mark_page_cached(cookie->netfs_data,
+ op->mapping, page);
+}
+EXPORT_SYMBOL(fscache_mark_page_cached);
+
+/**
* fscache_mark_pages_cached - Mark pages as being cached
* @op: The retrieval op pages are being marked for
* @pagevec: The pages to be marked
@@ -925,32 +1067,11 @@ EXPORT_SYMBOL(__fscache_uncache_page);
void fscache_mark_pages_cached(struct fscache_retrieval *op,
struct pagevec *pagevec)
{
- struct fscache_cookie *cookie = op->op.object->cookie;
unsigned long loop;
-#ifdef CONFIG_FSCACHE_STATS
- atomic_add(pagevec->nr, &fscache_n_marks);
-#endif
-
- for (loop = 0; loop < pagevec->nr; loop++) {
- struct page *page = pagevec->pages[loop];
-
- _debug("- mark %p{%lx}", page, page->index);
- if (TestSetPageFsCache(page)) {
- static bool once_only;
- if (!once_only) {
- once_only = true;
- printk(KERN_WARNING "FS-Cache:"
- " Cookie type %s marked page %lx"
- " multiple times\n",
- cookie->def->name, page->index);
- }
- }
- }
+ for (loop = 0; loop < pagevec->nr; loop++)
+ fscache_mark_page_cached(op, pagevec->pages[loop]);
- if (cookie->def->mark_pages_cached)
- cookie->def->mark_pages_cached(cookie->netfs_data,
- op->mapping, pagevec);
pagevec_reinit(pagevec);
}
EXPORT_SYMBOL(fscache_mark_pages_cached);