The patch titled
Subject: fs/mpage.c: fix mpage_writepage() for pages with buffers
has been added to the -mm tree. Its filename is
fix-mpage_writepage-for-pages-with-buffers.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/fix-mpage_writepage-for-pages-with-buffers.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/fix-mpage_writepage-for-pages-with-buffers.patch
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------------------------------------------------------
From: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Subject: fs/mpage.c: fix mpage_writepage() for pages with buffers
When using FAT on a block device which supports rw_page, we can hit
BUG_ON(!PageLocked(page)) in try_to_free_buffers(). This is because we
call clean_buffers() after unlocking the page we've written. Introduce a
new clean_page_buffers() which cleans all buffers associated with a page
and call it from within bdev_write_page().
Link: http://lkml.kernel.org/r/20171006211541.GA7409@xxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Reported-by: Toshi Kani <toshi.kani@xxxxxxx>
Reported-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
Tested-by: Toshi Kani <toshi.kani@xxxxxxx>
Acked-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/block_dev.c | 6 ++++--
fs/mpage.c | 14 +++++++++++---
include/linux/buffer_head.h | 1 +
3 files changed, 16 insertions(+), 5 deletions(-)
diff -puN fs/block_dev.c~fix-mpage_writepage-for-pages-with-buffers fs/block_dev.c
--- a/fs/block_dev.c~fix-mpage_writepage-for-pages-with-buffers
+++ a/fs/block_dev.c
@@ -716,10 +716,12 @@ int bdev_write_page(struct block_device
set_page_writeback(page);
result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, true);
- if (result)
+ if (result) {
end_page_writeback(page);
- else
+ } else {
+ clean_page_buffers(page);
unlock_page(page);
+ }
blk_queue_exit(bdev->bd_queue);
return result;
}
diff -puN fs/mpage.c~fix-mpage_writepage-for-pages-with-buffers fs/mpage.c
--- a/fs/mpage.c~fix-mpage_writepage-for-pages-with-buffers
+++ a/fs/mpage.c
@@ -468,6 +468,16 @@ static void clean_buffers(struct page *p
try_to_free_buffers(page);
}
+/*
+ * For situations where we want to clean all buffers attached to a page.
+ * We don't need to calculate how many buffers are attached to the page,
+ * we just need to specify a number larger than the maximum number of buffers.
+ */
+void clean_page_buffers(struct page *page)
+{
+ clean_buffers(page, PAGE_SIZE);
+}
+
static int __mpage_writepage(struct page *page, struct writeback_control *wbc,
void *data)
{
@@ -605,10 +615,8 @@ alloc_new:
if (bio == NULL) {
if (first_unmapped == blocks_per_page) {
if (!bdev_write_page(bdev, blocks[0] << (blkbits - 9),
- page, wbc)) {
- clean_buffers(page, first_unmapped);
+ page, wbc))
goto out;
- }
}
bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
BIO_MAX_PAGES, GFP_NOFS|__GFP_HIGH);
diff -puN include/linux/buffer_head.h~fix-mpage_writepage-for-pages-with-buffers include/linux/buffer_head.h
--- a/include/linux/buffer_head.h~fix-mpage_writepage-for-pages-with-buffers
+++ a/include/linux/buffer_head.h
@@ -232,6 +232,7 @@ int generic_write_end(struct file *, str
loff_t, unsigned, unsigned,
struct page *, void *);
void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
+void clean_page_buffers(struct page *page);
int cont_write_begin(struct file *, struct address_space *, loff_t,
unsigned, unsigned, struct page **, void **,
get_block_t *, loff_t *);
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
fix-mpage_writepage-for-pages-with-buffers.patch