2.6.28-stable review patch. If anyone has any objections, please let us know.
------------------
From: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
(cherry picked from commit 791b7f08954869d7b8ff438f3dac3cfb39778297)
When iterating through the pages which have mapped buffer_heads, we
failed to update the b_state value. This results in allocating blocks
at logical offset 0.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
fs/ext4/inode.c | 56 +++++++++++++++++++++++++++++++++++++++-----------------
1 file changed, 39 insertions(+), 17 deletions(-)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1644,35 +1644,39 @@ struct mpage_da_data {
*/
static int mpage_da_submit_io(struct mpage_da_data *mpd)
{
- struct address_space *mapping = mpd->inode->i_mapping;
- int ret = 0, err, nr_pages, i;
- unsigned long index, end;
- struct pagevec pvec;
long pages_skipped;
+ struct pagevec pvec;
+ unsigned long index, end;
+ int ret = 0, err, nr_pages, i;
+ struct inode *inode = mpd->inode;
+ struct address_space *mapping = inode->i_mapping;
BUG_ON(mpd->next_page <= mpd->first_page);
- pagevec_init(&pvec, 0);
+ /*
+ * We need to start from the first_page to the next_page - 1
+ * to make sure we also write the mapped dirty buffer_heads.
+ * If we look at mpd->lbh.b_blocknr we would only be looking
+ * at the currently mapped buffer_heads.
+ */
index = mpd->first_page;
end = mpd->next_page - 1;
+ pagevec_init(&pvec, 0);
while (index <= end) {
- /*
- * We can use PAGECACHE_TAG_DIRTY lookup here because
- * even though we have cleared the dirty flag on the page
- * We still keep the page in the radix tree with tag
- * PAGECACHE_TAG_DIRTY. See clear_page_dirty_for_io.
- * The PAGECACHE_TAG_DIRTY is cleared in set_page_writeback
- * which is called via the below writepage callback.
- */
- nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
- PAGECACHE_TAG_DIRTY,
- min(end - index,
- (pgoff_t)PAGEVEC_SIZE-1) + 1);
+ nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
if (nr_pages == 0)
break;
for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i];
+ index = page->index;
+ if (index > end)
+ break;
+ index++;
+
+ BUG_ON(!PageLocked(page));
+ BUG_ON(PageWriteback(page));
+
pages_skipped = mpd->wbc->pages_skipped;
err = mapping->a_ops->writepage(page, mpd->wbc);
if (!err && (pages_skipped == mpd->wbc->pages_skipped))
@@ -2086,11 +2090,29 @@ static int __mpage_da_writepage(struct p
bh = head;
do {
BUG_ON(buffer_locked(bh));
+ /*
+ * We need to try to allocate
+ * unmapped blocks in the same page.
+ * Otherwise we won't make progress
+ * with the page in ext4_da_writepage
+ */
if (buffer_dirty(bh) &&
(!buffer_mapped(bh) || buffer_delay(bh))) {
mpage_add_bh_to_extent(mpd, logical, bh);
if (mpd->io_done)
return MPAGE_DA_EXTENT_TAIL;
+ } else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
+ /*
+ * mapped dirty buffer. We need to update
+ * the b_state because we look at
+ * b_state in mpage_da_map_blocks. We don't
+ * update b_size because if we find an
+ * unmapped buffer_head later we need to
+ * use the b_state flag of that buffer_head.
+ */
+ if (mpd->lbh.b_size == 0)
+ mpd->lbh.b_state =
+ bh->b_state & BH_FLAGS;
}
logical++;
} while ((bh = bh->b_this_page) != head);
--
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