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[PATCH 03/13] FS-Cache: Validate page mapping pointer value | |
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Add information to indicate whether page->mapping should have a value or not,
and to log a warning if it is wrong.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---
fs/cachefiles/rdwr.c | 26 +++++++++++++++++---------
fs/fscache/page.c | 36 +++++++++++++++++++++++++++++++++---
include/linux/fscache-cache.h | 6 ++++--
3 files changed, 54 insertions(+), 14 deletions(-)
diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
index 0186fc1..e8c3766 100644
--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -177,7 +177,7 @@ static void cachefiles_read_copier(struct fscache_operation *_op)
if (PageUptodate(monitor->back_page)) {
copy_highpage(monitor->netfs_page, monitor->back_page);
fscache_mark_page_cached(monitor->op,
- monitor->netfs_page);
+ monitor->netfs_page, true);
error = 0;
} else if (!PageError(monitor->back_page)) {
/* the page has probably been truncated */
@@ -334,7 +334,7 @@ backing_page_already_present:
backing_page_already_uptodate:
_debug("- uptodate");
- fscache_mark_page_cached(op, netpage);
+ fscache_mark_page_cached(op, netpage, true);
copy_highpage(netpage, backpage);
fscache_end_io(op, netpage, 0);
@@ -446,7 +446,7 @@ int cachefiles_read_or_alloc_page(struct fscache_retrieval *op,
&pagevec);
} else if (cachefiles_has_space(cache, 0, 1) == 0) {
/* there's space in the cache we can use */
- fscache_mark_page_cached(op, page);
+ fscache_mark_page_cached(op, page, true);
ret = -ENODATA;
} else {
ret = -ENOBUFS;
@@ -622,7 +622,7 @@ static int cachefiles_read_backing_file(struct cachefiles_object *object,
page_cache_release(backpage);
backpage = NULL;
- fscache_mark_page_cached(op, netpage);
+ fscache_mark_page_cached(op, netpage, true);
page_cache_get(netpage);
if (!pagevec_add(&lru_pvec, netpage))
@@ -704,6 +704,14 @@ int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op,
object->fscache.debug_id, atomic_read(&op->op.usage),
*nr_pages);
+ {
+ struct page *q, *_q;
+ list_for_each_entry_safe(q, _q, pages, lru) {
+ ASSERT(!q->mapping);
+ ASSERT(!PageFsCache(q));
+ }
+ }
+
if (!object->backer)
return -ENOBUFS;
@@ -757,13 +765,13 @@ int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op,
(*nr_pages)--;
nrbackpages++;
} else if (space && pagevec_add(&pagevec, page) == 0) {
- fscache_mark_pages_cached(op, &pagevec);
+ fscache_mark_pages_cached(op, &pagevec, false);
ret = -ENODATA;
}
}
if (pagevec_count(&pagevec) > 0)
- fscache_mark_pages_cached(op, &pagevec);
+ fscache_mark_pages_cached(op, &pagevec, false);
if (list_empty(pages))
ret = 0;
@@ -809,7 +817,7 @@ int cachefiles_allocate_page(struct fscache_retrieval *op,
ret = cachefiles_has_space(cache, 0, 1);
if (ret == 0)
- fscache_mark_page_cached(op, page);
+ fscache_mark_page_cached(op, page, true);
else
ret = -ENOBUFS;
@@ -852,11 +860,11 @@ int cachefiles_allocate_pages(struct fscache_retrieval *op,
list_for_each_entry(page, pages, lru) {
if (pagevec_add(&pagevec, page) == 0)
- fscache_mark_pages_cached(op, &pagevec);
+ fscache_mark_pages_cached(op, &pagevec, false);
}
if (pagevec_count(&pagevec) > 0)
- fscache_mark_pages_cached(op, &pagevec);
+ fscache_mark_pages_cached(op, &pagevec, false);
ret = -ENODATA;
} else {
ret = -ENOBUFS;
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index d7c663c..5e793b5 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -918,11 +918,13 @@ 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
+ * @should_have_mapping: True if the pages should have a mapping set
*
* 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)
+void fscache_mark_page_cached(struct fscache_retrieval *op, struct page *page,
+ bool should_have_mapping)
{
struct fscache_cookie *cookie = op->op.object->cookie;
@@ -941,6 +943,31 @@ void fscache_mark_page_cached(struct fscache_retrieval *op, struct page *page)
cookie->def->name, page->index);
}
}
+ if (should_have_mapping && !page->mapping) {
+ static bool once_only;
+ if (!once_only) {
+ once_only = 1;
+ printk(KERN_ALERT
+ "FSC: page:%p count:%d mapcount:%d NO_MAPPING"
+ " index:%#lx\n",
+ page, page_count(page), page_mapcount(page),
+ page->index);
+ WARN_ON(1);
+ }
+ }
+
+ if (!should_have_mapping && page->mapping) {
+ static bool once_only;
+ if (!once_only) {
+ once_only = 1;
+ printk(KERN_ALERT
+ "FSC: page:%p count:%d mapcount:%d MAPPING:%p"
+ " index:%#lx\n",
+ page, page_count(page), page_mapcount(page),
+ page->mapping, page->index);
+ WARN_ON(1);
+ }
+ }
if (cookie->def->mark_page_cached)
cookie->def->mark_page_cached(cookie->netfs_data,
@@ -952,17 +979,20 @@ 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
+ * @should_have_mapping: True if the pages should have a mapping set
*
* Mark a bunch of netfs pages as being cached. After this is called,
* the netfs must call fscache_uncache_page() to remove the mark.
*/
void fscache_mark_pages_cached(struct fscache_retrieval *op,
- struct pagevec *pagevec)
+ struct pagevec *pagevec,
+ bool should_have_mapping)
{
unsigned long loop;
for (loop = 0; loop < pagevec->nr; loop++)
- fscache_mark_page_cached(op, pagevec->pages[loop]);
+ fscache_mark_page_cached(op, pagevec->pages[loop],
+ should_have_mapping);
pagevec_reinit(pagevec);
}
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index 485c011..ae155f1 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -505,10 +505,12 @@ extern void fscache_withdraw_cache(struct fscache_cache *cache);
extern void fscache_io_error(struct fscache_cache *cache);
extern void fscache_mark_page_cached(struct fscache_retrieval *op,
- struct page *page);
+ struct page *page,
+ bool should_have_mapping);
extern void fscache_mark_pages_cached(struct fscache_retrieval *op,
- struct pagevec *pagevec);
+ struct pagevec *pagevec,
+ bool should_have_mapping);
extern bool fscache_object_sleep_till_congested(signed long *timeoutp);
--
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