The patch titled
mm: write_cache_pages writepage error fix
has been added to the -mm tree. Its filename is
mm-write_cache_pages-writepage-error-fix.patch
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------------------------------------------------------
Subject: mm: write_cache_pages writepage error fix
From: Nick Piggin <npiggin@xxxxxxx>
In write_cache_pages, if ret signals a real error, but we still have some
pages left in the pagevec, done would be set to 1, but the remaining pages
would continue to be processed and ret will be overwritten in the process.
It could easily be overwritten with success, and thus success will be
returned even if there is an error. Thus the caller is told all writes
succeeded, wheras in reality some did not.
Fix this by bailing immediately if there is an error, and retaining the
first error code.
This is a data integrity bug.
Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
Cc: Chris Mason <chris.mason@xxxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: jim owens <jowens@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page-writeback.c | 24 +++++++++++++++++++-----
1 file changed, 19 insertions(+), 5 deletions(-)
diff -puN mm/page-writeback.c~mm-write_cache_pages-writepage-error-fix mm/page-writeback.c
--- a/mm/page-writeback.c~mm-write_cache_pages-writepage-error-fix
+++ a/mm/page-writeback.c
@@ -944,12 +944,26 @@ retry:
}
ret = (*writepage)(page, wbc, data);
+ if (unlikely(ret)) {
+ if (ret == AOP_WRITEPAGE_ACTIVATE) {
+ unlock_page(page);
+ ret = 0;
+ } else {
+ /*
+ * done_index is set past this page,
+ * so media errors will not choke
+ * background writeout for the entire
+ * file. This has consequences for
+ * range_cyclic semantics (ie. it may
+ * not be suitable for data integrity
+ * writeout).
+ */
+ done = 1;
+ break;
+ }
+ }
- if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE)) {
- unlock_page(page);
- ret = 0;
- }
- if (ret || (--nr_to_write <= 0))
+ if (--nr_to_write <= 0)
done = 1;
if (wbc->nonblocking && bdi_write_congested(bdi)) {
wbc->encountered_congestion = 1;
_
Patches currently in -mm which might be from npiggin@xxxxxxx are
mm-increase-the-default-mlock-limit-from-32k-to-64k.patch
fs-remove-prepare_write-commit_write.patch
linux-next.patch
mm-dont-mark_page_accessed-in-fault-path.patch
mm-invoke-oom-killer-from-page-fault.patch
mm-invoke-oom-killer-from-page-fault-fix.patch
mm-invoke-oom-killer-from-page-fault-fix-fix-2.patch
mm-write_cache_pages-cyclic-fix.patch
mm-write_cache_pages-cyclic-fix-fix.patch
mm-write_cache_pages-early-loop-termination.patch
mm-write_cache_pages-writepage-error-fix.patch
mm-write_cache_pages-integrity-fix.patch
mm-write_cache_pages-cleanups.patch
mm-write_cache_pages-optimise-page-cleaning.patch
mm-write_cache_pages-terminate-quickly.patch
mm-write_cache_pages-more-terminate-quickly.patch
mm-do_sync_mapping_range-integrity-fix.patch
reiser4.patch
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