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-rw-r--r--mm/filemap.c53
1 files changed, 20 insertions, 33 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 5d5449f3d41c..462cda58a18e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1325,9 +1325,10 @@ struct page *filemap_nopage(struct vm_area_struct *area,
unsigned long size, pgoff;
int did_readaround = 0, majmin = VM_FAULT_MINOR;
+ BUG_ON(!(area->vm_flags & VM_CAN_INVALIDATE));
+
pgoff = ((address-area->vm_start) >> PAGE_CACHE_SHIFT) + area->vm_pgoff;
-retry_all:
size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
if (pgoff >= size)
goto outside_data_content;
@@ -1349,7 +1350,7 @@ retry_all:
* Do we have something in the page cache already?
*/
retry_find:
- page = find_get_page(mapping, pgoff);
+ page = find_lock_page(mapping, pgoff);
if (!page) {
unsigned long ra_pages;
@@ -1383,7 +1384,7 @@ retry_find:
start = pgoff - ra_pages / 2;
do_page_cache_readahead(mapping, file, start, ra_pages);
}
- page = find_get_page(mapping, pgoff);
+ page = find_lock_page(mapping, pgoff);
if (!page)
goto no_cached_page;
}
@@ -1392,13 +1393,19 @@ retry_find:
ra->mmap_hit++;
/*
- * Ok, found a page in the page cache, now we need to check
- * that it's up-to-date.
+ * We have a locked page in the page cache, now we need to check
+ * that it's up-to-date. If not, it is going to be due to an error.
*/
- if (!PageUptodate(page))
+ if (unlikely(!PageUptodate(page)))
goto page_not_uptodate;
-success:
+ /* Must recheck i_size under page lock */
+ size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ if (unlikely(pgoff >= size)) {
+ unlock_page(page);
+ goto outside_data_content;
+ }
+
/*
* Found the page and have a reference on it.
*/
@@ -1440,6 +1447,7 @@ no_cached_page:
return NOPAGE_SIGBUS;
page_not_uptodate:
+ /* IO error path */
if (!did_readaround) {
majmin = VM_FAULT_MAJOR;
count_vm_event(PGMAJFAULT);
@@ -1451,37 +1459,15 @@ page_not_uptodate:
* because there really aren't any performance issues here
* and we need to check for errors.
*/
- lock_page(page);
-
- /* Somebody truncated the page on us? */
- if (!page->mapping) {
- unlock_page(page);
- page_cache_release(page);
- goto retry_all;
- }
-
- /* Somebody else successfully read it in? */
- if (PageUptodate(page)) {
- unlock_page(page);
- goto success;
- }
ClearPageError(page);
error = mapping->a_ops->readpage(file, page);
- if (!error) {
- wait_on_page_locked(page);
- if (PageUptodate(page))
- goto success;
- } else if (error == AOP_TRUNCATED_PAGE) {
- page_cache_release(page);
+ page_cache_release(page);
+
+ if (!error || error == AOP_TRUNCATED_PAGE)
goto retry_find;
- }
- /*
- * Things didn't work out. Return zero to tell the
- * mm layer so, possibly freeing the page cache page first.
- */
+ /* Things didn't work out. Return zero to tell the mm layer so. */
shrink_readahead_size_eio(file, ra);
- page_cache_release(page);
return NOPAGE_SIGBUS;
}
EXPORT_SYMBOL(filemap_nopage);
@@ -1674,6 +1660,7 @@ int generic_file_mmap(struct file * file, struct vm_area_struct * vma)
return -ENOEXEC;
file_accessed(file);
vma->vm_ops = &generic_file_vm_ops;
+ vma->vm_flags |= VM_CAN_INVALIDATE;
return 0;
}