Comments
Patch
@@ -203,11 +203,12 @@ static void ext4_end_bio(struct bio *bio, int error)
for (i = 0; i < io_end->num_io_pages; i++) {
struct page *page = io_end->pages[i]->p_page;
struct buffer_head *bh, *head;
- int partial_write = 0;
head = page_buffers(page);
- if (error)
+ if (error) {
SetPageError(page);
+ set_bit(AS_EIO, &page->mapping->flags);
+ }
BUG_ON(!head);
if (head->b_size != PAGE_CACHE_SIZE) {
loff_t offset;
@@ -220,29 +221,14 @@ static void ext4_end_bio(struct bio *bio, int error)
(offset+bh->b_size <= io_end_offset)) {
if (error)
buffer_io_error(bh);
-
}
- if (buffer_delay(bh))
- partial_write = 1;
- else if (!buffer_mapped(bh))
+ if (!buffer_mapped(bh))
clear_buffer_dirty(bh);
- else if (buffer_dirty(bh))
- partial_write = 1;
offset += bh->b_size;
bh = bh->b_this_page;
} while (bh != head);
}
- /*
- * If this is a partial write which happened to make
- * all buffers uptodate then we can optimize away a
- * bogus readpage() for the next read(). Here we
- * 'discover' whether the page went uptodate as a
- * result of this (potentially partial) write.
- */
- if (!partial_write)
- SetPageUptodate(page);
-
put_io_page(io_end->pages[i]);
}
io_end->num_io_pages = 0;
In the bio completion routine, we should not be setting PageUptodate at all -- it's set at sys_write() time, and is unaffected by success/failure of the write to disk. This can cause a page corruption bug when block size < page size if we have only written a single block -- we might end up setting the entire PageUptodate, which will cause subsequent reads to get bad data. This commit also fixes ext4_end_bio() to set AS_EIO in the page->mapping->flags on error, which was left out by mistake. Signed-off-by: Curt Wohlgemuth <curtw@google.com> Reported-by: Jim Meyering <jim@meyering.net> Reported-by: Hugh Dickins <hughd@google.com> Cc: Mingming Cao <cmm@us.ibm.com> --- Changlog since v1: - Added commit message text about setting AS_EIO for the page on error. - Continue to loop over all BHs in a page and emit unique errors for each of them. --- fs/ext4/page-io.c | 22 ++++------------------ 1 files changed, 4 insertions(+), 18 deletions(-)