The -EIO returned here can end up overriding whatever error is marked in
the address space, and be returned at fsync time, even when there is a
more appropriate error stored in the mapping.

Read errors are also sometimes tracked on a per-page level using
PG_error. Suppose we have a read error on a page, and then that page is
subsequently dirtied by overwriting the whole page. Writeback doesn't
clear PG_error, so we can then end up successfully writing back that
page and still return -EIO on fsync.

Worse yet, PG_error is cleared during a sync() syscall, but the -EIO
return from that is silently discarded. Any subsystem that is relying on
PG_error to report errors during fsync can easily lose writeback errors
due to this. All you need is a stray sync() call to wait for writeback
to complete and you've lost the error.

Since the handling of the PG_error flag is somewhat inconsistent across
subsystems, let's just rely on marking the address space when there are
writeback errors. Change the TestClearPageError call to ClearPageError,
and make __filemap_fdatawait_range a void return function.

Signed-off-by: Jeff Layton <>
 mm/filemap.c | 20 +++++---------------
 1 file changed, 5 insertions(+), 15 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index eaec849ec8e5..ffdc21762e2f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -363,17 +363,16 @@ int filemap_flush(struct address_space *mapping)
-static int __filemap_fdatawait_range(struct address_space *mapping,
+static void __filemap_fdatawait_range(struct address_space *mapping,
                                     loff_t start_byte, loff_t end_byte)
        pgoff_t index = start_byte >> PAGE_SHIFT;
        pgoff_t end = end_byte >> PAGE_SHIFT;
        struct pagevec pvec;
        int nr_pages;
-       int ret = 0;
        if (end_byte < start_byte)
-               goto out;
+               return;
        pagevec_init(&pvec, 0);
        while ((index <= end) &&
@@ -390,14 +389,11 @@ static int __filemap_fdatawait_range(struct address_space 
-                       if (TestClearPageError(page))
-                               ret = -EIO;
+                       ClearPageError(page);
-       return ret;
@@ -414,14 +410,8 @@ static int __filemap_fdatawait_range(struct address_space 
 int filemap_fdatawait_range_since(struct address_space *mapping,
                loff_t start_byte, loff_t end_byte, errseq_t since)
-       int ret, ret2;
-       ret = __filemap_fdatawait_range(mapping, start_byte, end_byte);
-       ret2 = filemap_check_wb_error(mapping, since);
-       if (!ret)
-               ret = ret2;
-       return ret;
+       __filemap_fdatawait_range(mapping, start_byte, end_byte);
+       return filemap_check_wb_error(mapping, since);

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