Hi,
the patch below should be used instead of
ext4-Add-validation-to-jbd-lock-inversion-patch-and.patch
to check whether writepage got all buffers mapped. It duplicates less
code than the original patch and I think there's also nicer separation
between parts doing sanity checks and parts doing real work.
Honza
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
---
ext4: Add checks to writepage()
Add checks to writepage() calls to check that all pages are properly
mapped and not delayed.
Signed-off-by: Jan Kara <jack@xxxxxxx>
Index: linux-2.6-linus/fs/ext4/inode.c
===================================================================
--- linux-2.6-linus.orig/fs/ext4/inode.c
+++ linux-2.6-linus/fs/ext4/inode.c
@@ -1479,6 +1479,11 @@ static int jbd2_journal_dirty_data_fn(ha
return 0;
}
+static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
+{
+ return !buffer_mapped(bh) || buffer_delay(bh);
+}
+
/*
* Note that we don't need to start a transaction unless we're journaling
* data because we should have holes filled from ext4_page_mkwrite(). If
@@ -1582,7 +1587,18 @@ out_put:
static int ext4_ordered_writepage(struct page *page,
struct writeback_control *wbc)
{
+ struct inode *inode = page->mapping->host;
+ loff_t size = i_size_read(inode);
+ loff_t len;
+
J_ASSERT(PageLocked(page));
+ J_ASSERT(page_has_buffers(page));
+ if (page->index == size >> PAGE_CACHE_SHIFT)
+ len = size & ~PAGE_CACHE_MASK;
+ else
+ len = PAGE_CACHE_SIZE;
+ BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
+ ext4_bh_unmapped_or_delay));
/*
* We give up here if we're reentered, because it might be for a
@@ -1611,6 +1627,19 @@ static int __ext4_writeback_writepage(st
static int ext4_writeback_writepage(struct page *page,
struct writeback_control *wbc)
{
+ struct inode *inode = page->mapping->host;
+ loff_t size = i_size_read(inode);
+ loff_t len;
+
+ J_ASSERT(PageLocked(page));
+ J_ASSERT(page_has_buffers(page));
+ if (page->index == size >> PAGE_CACHE_SHIFT)
+ len = size & ~PAGE_CACHE_MASK;
+ else
+ len = PAGE_CACHE_SIZE;
+ BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
+ ext4_bh_unmapped_or_delay));
+
if (!ext4_journal_current_handle())
return __ext4_writeback_writepage(page, wbc);
@@ -1671,10 +1700,23 @@ out:
static int ext4_journalled_writepage(struct page *page,
struct writeback_control *wbc)
{
+ struct inode *inode = page->mapping->host;
+ loff_t size = i_size_read(inode);
+ loff_t len;
+
+ J_ASSERT(PageLocked(page));
+ J_ASSERT(page_has_buffers(page));
+ if (page->index == size >> PAGE_CACHE_SHIFT)
+ len = size & ~PAGE_CACHE_MASK;
+ else
+ len = PAGE_CACHE_SIZE;
+ BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
+ ext4_bh_unmapped_or_delay));
+
if (ext4_journal_current_handle())
goto no_write;
- if (!page_has_buffers(page) || PageChecked(page)) {
+ if (PageChecked(page)) {
/*
* It's mmapped pagecache. Add buffers and journal it. There
* doesn't seem much point in redirtying the page here.
--
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