Re: ext2 related,two oops with 2.5.12 on ATA66 disk.

From: Andrew Morton (akpm@zip.com.au)
Date: Fri May 03 2002 - 15:55:09 EST


Luigi Genoni wrote:
>
> HI,
>
> this morning, going at work, I found those two oops (repeated a lto of
> times), on the Pentium III 512MB ram, i810 chipset, Maxtor 32049H2 ATA66
> disk.
>
> buffer layer error at buffer.c:1380
>

Yup, thanks. dirty, uptodate, unmapped buffer outside
i_size. I have a few fixes in the works; the below
one should make this go away.

--- 2.5.13/mm/page-writeback.c~writepage-versus-set_page_dirty Fri May 3 00:48:13 2002
+++ 2.5.13-akpm/mm/page-writeback.c Fri May 3 00:48:13 2002
@@ -475,8 +475,13 @@ int __set_page_dirty_buffers(struct page
                 struct buffer_head *bh = head;
 
                 do {
- if (buffer_uptodate(bh))
+ if (buffer_uptodate(bh)) {
+ if (!buffer_mapped(bh))
+ buffer_error();
                                 set_buffer_dirty(bh);
+ } else {
+ buffer_error();
+ }
                         bh = bh->b_this_page;
                 } while (bh != head);
         }
--- 2.5.13/fs/buffer.c~writepage-versus-set_page_dirty Fri May 3 00:48:13 2002
+++ 2.5.13-akpm/fs/buffer.c Fri May 3 00:48:43 2002
@@ -1290,6 +1290,16 @@ static int __block_write_full_page(struc
                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
         }
 
+ /*
+ * Be very careful. We have no exclusion from __set_page_dirty_buffers
+ * here, and the (potentially unmapped) buffers may become dirty at
+ * any time. If a buffer becomes dirty here after we've inspected it
+ * then we just miss that fact, and the page stays dirty.
+ *
+ * Buffers outside i_size may be dirtied by __set_page_dirty_buffers;
+ * handle that here by just cleaning them.
+ */
+
         block = page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
         head = page_buffers(page);
         bh = head;
@@ -1300,8 +1310,7 @@ static int __block_write_full_page(struc
          */
         do {
                 if (block > last_block) {
- if (buffer_dirty(bh))
- buffer_error();
+ clear_buffer_dirty(bh);
                         if (buffer_mapped(bh))
                                 buffer_error();
                         /*
@@ -1329,11 +1338,9 @@ static int __block_write_full_page(struc
 
         do {
                 get_bh(bh);
- if (buffer_dirty(bh)) {
+ if (buffer_mapped(bh) && buffer_dirty(bh)) {
                         lock_buffer(bh);
- if (buffer_dirty(bh)) {
- if (!buffer_mapped(bh))
- buffer_error();
+ if (test_clear_buffer_dirty(bh)) {
                                 if (!buffer_uptodate(bh))
                                         buffer_error();
                                 set_buffer_async_io(bh);
@@ -1355,7 +1362,6 @@ static int __block_write_full_page(struc
         do {
                 struct buffer_head *next = bh->b_this_page;
                 if (buffer_async(bh)) {
- clear_buffer_dirty(bh);
                         submit_bh(WRITE, bh);
                         nr_underway++;
                 }
-
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This archive was generated by hypermail 2b29 : Tue May 07 2002 - 22:00:21 EST